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    <title>Transport Research International Documentation (TRID)</title>
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    <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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Navigating the sustainability transition in aviation: the case of liquid hydrogen aircraft adoption by low-cost airlines</title>
      <link>https://trid.trb.org/View/2679128</link>
      <description><![CDATA[Innovations in lightweight aircraft materials over past decades have made improvements in engine efficiency and aircraft performance. This has allowed the aviation industry to greatly enhance fuel efficiency over the past 50 years. In order to reach its 2050 net-zero environmental target, the industry is exploring additional technologies to reduce the environmental impact, such as alternative aircraft propulsion. Liquid hydrogen aircraft propulsion, due to its high gravimetric energy density and lightweight nature, is a promising option. Low-cost airlines have been identified as a suitable market for the introduction of commercial liquid hydrogen aircraft, covering many short and medium haul flights.]]></description>
      <pubDate>Tue, 30 Jun 2026 16:54:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2679128</guid>
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    <item>
      <title>The challenges of integrating alternative fuels in airport development and how they can be overcome</title>
      <link>https://trid.trb.org/View/2716588</link>
      <description><![CDATA[This paper investigates the challenges, strategies and implications of integrating alternative fuels, particularly sustainable aviation fuels (SAF) and liquid hydrogen, into airport development and operations. It examines both fuels as complementary pathways within aviation’s broader decarbonisation effort, highlighting that while SAF enables a relatively seamless near-term transition through drop-in blends, hydrogen represents a transformative, long-term shift requiring new infrastructure, supply chains and planning paradigms. The paper discusses how airports should adapt their master planning to accommodate uncertain technological timelines, evolving regulations and emerging fuel ecosystems. It identifies scenario-driven, modular master planning as a key tool for de-risking investment decisions and ensuring flexibility as technologies mature. Pilot initiatives such as the Hydrogen Aviation Lab and the GOLIAT project illustrate how empirical testing and cross-sector collaboration can close existing knowledge gaps around liquid hydrogen handling, safety and logistics. Economic considerations and new partnership models are also discussed, as airports move from isolated operational roles to active participation in fuel supply chains. The analysis finds that successful integration of alternative fuels will depend on shared investment frameworks, harmonised regulation and coordinated development of scalable infrastructure across the aviation ecosystem. The paper concludes that while many uncertainties remain, airports must begin preparing now through adaptable infrastructure planning, early demonstration projects and cooperation across industry boundaries. Airports that embrace these strategies will position themselves as key enablers of aviation’s transition towards net zero emissions by 2050. This article is also included in The Business & Management Collection which can be accessed at https://hstalks.com/business/.]]></description>
      <pubDate>Wed, 24 Jun 2026 11:31:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2716588</guid>
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    <item>
      <title>Mitigating resource mismatches-oriented optimal cross-regional green hydrogen supply strategy considering cost and risk</title>
      <link>https://trid.trb.org/View/2604732</link>
      <description><![CDATA[Low-cost green hydrogen can be produced via water electrolysis in regions with abundant renewable energy; however, the geographical mismatch between hydrogen supply and demand necessitates efficient production site and transport mode selection to ensure its cost-effectiveness and safety. This study addresses this challenge by developing the cross-regional hydrogen supply strategies optimization model under hydrogen supply costs and risks minimization goals for the government in areas with limited resources. A wind-solar-battery renewable energy system is proposed for green hydrogen production, incorporating tube trailers, liquid hydrogen trucks, and pipelines as transport options, to jointly determine optimal production site locations and transport routes. A hydrogen risk assessment method is proposed, which combines population density and transportation distance variables with a natural language processing-aided analysis of historical hydrogen accident frequencies. A case study conducted in Chongqing, China, demonstrates the model’s effectiveness through various scenario analyses. The study reveals a trade-off between cost and risk across different hydrogen supply strategies and identifies a negative power-law relationship between the distance of production sites and production costs, indicating that cost savings diminish as transport distances increase. Furthermore, sensitivity analysis is carried out to explore the uncertainties in hydrogen demand, the impacts of extreme heat weather, the technology development of tube-trailer storage and transport, and the policy support for risk and investment mitigation.]]></description>
      <pubDate>Wed, 17 Jun 2026 16:14:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2604732</guid>
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    <item>
      <title>LH₂ Cooling Penalties for Superconducting Motors in a Hydrogen-Powered Regional Aircraft</title>
      <link>https://trid.trb.org/View/2665498</link>
      <description><![CDATA[Liquid hydrogen (LH₂) aircraft concepts offer the potential to provide “free” cryogenic cooling for superconducting motors (SCMs) and cryogenic power electronics (CPEs). This can lead to significant weight reductions by eliminating the need for bulky cryocoolers. However, the LH₂ system’s capacity to provide free cooling varies with aircraft power. Unlike cryocoolers, it is not sufficient to evaluate performance solely at maximum heat load. Instead, detailed heat load profiles must be established and evaluated against the aircraft’s hydrogen consumption profile across the entire mission to detect if there are periods with insufficient cooling capacity. In this article, we perform a detailed study of the amount of hydrogen it takes to compensate for the cooling deficiencies in an SCM with high-temperature superconductor (HTS) armature windings. We also study tradeoffs in the SCM’s slot design. The results show that this SCM can be cooled without excessive hydrogen penalties. The methodology followed in this article has general applicability, and the steps are detailed in equations and summarized in a flowchart.]]></description>
      <pubDate>Fri, 29 May 2026 14:09:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2665498</guid>
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    <item>
      <title>Infrastructure and supply pathways for liquid hydrogen at airports: A technical framework for feasibility and airport master planning</title>
      <link>https://trid.trb.org/View/2681227</link>
      <description><![CDATA[Hydrogen-powered aviation is increasingly considered a promising option for reducing aviation emissions, particularly on regional and short-haul routes. The use of liquid hydrogen (LH2) as an aviation fuel offers significant environmental benefits, but its adoption and integration require the development of new infrastructure at airports, including hydrogen liquefaction facilities. This paper lays the groundwork for assessing the feasibility of onsite hydrogen liquefaction by examining the technical principles, supply chain configurations and spatial requirements of such facilities. The study starts with a comprehensive overview of hydrogen as an aviation fuel, outlines current aircraft developments and compares three LH2 supply pathways: centralised offsite liquefaction, onsite liquefaction from offsite hydrogen, and full onsite production and liquefaction. Drawing on real-world examples from operational liquefaction facilities in South Korea, the US and Canada, this paper presents a generalised layout for airport-based liquefaction facilities, detailing core liquefaction process zones and supporting systems. These zones serve as a planning tool for early-stage spatial assessments, safety zoning and integration of hydrogen liquefaction facilities with existing airport infrastructure. The layout presented in this paper is modular and scalable, allowing airports to adapt infrastructure to varying hydrogen demand and spatial constraints. While current liquefaction plants demonstrate technical feasibility and viability at scales up to 90 tons per day (TPD), this paper explores the practical challenges of implementing such infrastructure at airports. These include gaining access to gaseous hydrogen via backbone networks, energy demands, constrained land availability, safety zoning requirements and regulatory complexity. Rather than resolving these issues, the paper provides a descriptive framework to understand and assess them, supporting airport master planning and future airport feasibility studies. This article is also included in The Business & Management Collection which can be accessed at https://hstalks.com/business/.]]></description>
      <pubDate>Wed, 25 Mar 2026 16:40:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2681227</guid>
    </item>
    <item>
      <title>Hydrogen Leakage Across an Airport Liquid Hydrogen Supply Chain</title>
      <link>https://trid.trb.org/View/2666083</link>
      <description><![CDATA[The use of liquid hydrogen (LH2) in aviation has the potential to substantially reduce greenhouse-gas emissions on short- and medium-haul flights. However, if hydrogen is released into the atmosphere, it can indirectly increase global warming. This study quantifies potential hydrogen releases across the airport supply chain. The system boundary includes five supply chain components: on-site liquefaction, liquid hydrogen storage, apron distribution, aircraft refueling, and the aircraft parking time on the ground. The analysis distinguishes atmospheric releases from losses that are contained or recovered and thus not considered atmospheric leakage. This review provides not only overview of hydrogen losses but also a basis for quantifying leakage rates for airports under different scenarios. The results show that most hydrogen losses can be captured and recovered, achieving near-zero routine emissions for the majority of supply-chain components. Only a small, unavoidable fraction of hydrogen is ultimately released to the atmosphere as leakage.]]></description>
      <pubDate>Mon, 23 Mar 2026 15:15:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2666083</guid>
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    <item>
      <title>A Risk Analysis of the Release of Liquid Hydrogen in Road Tunnels: The Effects of Mechanical Ventilation Combined with Geometric and Traffic Characteristics</title>
      <link>https://trid.trb.org/View/2657951</link>
      <description><![CDATA[The transportation of liquid hydrogen (LH2) via road tankers could prove to be the most cost-effective short-term option for long-distance delivery. However, there are significant risks, particularly in confined spaces like road tunnels. An accidental release of LH2 in these structures is likely to create a flammable hydrogen cloud, the explosion of which generates overpressures whose magnitude depends on several mutually dependent variables, including geometry, traffic, and ventilation. Nevertheless, the combined effect of the above-mentioned variables on user safety in the event of an accidental leakage and explosion of LH2 from a road tanker in a tunnel has yet to be investigated in detail. This study develops 3D CFD models of both the release and explosion of LH2 to address this issue, along with a comprehensive parametric analysis that considers different tunnel lengths, negative and positive longitudinal slopes, traffic volumes, and ventilation types (i.e., natural or longitudinal mechanical). The CFD code used was preliminarily calibrated against experimental literature tests. Subsequently, a risk analysis was carried out using the CFD results in terms of overpressures, which, combined with a probit function, made it possible to estimate the number of potential fatalities. Consequently, a probability matrix of the risk of having a given number (N) of fatalities was built as a function of the tunnel length, ventilation type (i.e., natural or mechanical), longitudinal slope, and traffic volume. The results revealed the benefits of positive gradients as well as of implementing a longitudinal mechanical ventilation system. In contrast, longer tunnels increase the probability of having a given number of fatalities. This study might serve as a reference for tunnel operators in the choice of mitigation measures and/or traffic control strategies to limit the negative consequences of the release of liquid hydrogen in road tunnels.]]></description>
      <pubDate>Wed, 18 Feb 2026 11:59:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2657951</guid>
    </item>
    <item>
      <title>Operational performance in sustainable aviation: an in-depth analysis of turnaround times of future commercial narrowbody liquid hydrogen aircraft</title>
      <link>https://trid.trb.org/View/2540039</link>
      <description><![CDATA[Liquid hydrogen (LH2) aircraft are expected to play a significant role in decarbonising the aviation industry. Their adoption will have multiple operational impacts, one of the most relevant for airlines being associated with the potential changes in turnaround times. This paper quantifies the expected changes in turnaround times of commercial narrowbody LH2 aircraft and assesses the impact of these new turnaround times on airline operational performance using actual empirical data. The main conclusion of this study is that the changes in turnaround times of LH2 aircraft are expected to have a rather marginal impact on airline operational performance, and therefore LH2 aircraft propulsion technology has the potential, following the implementation of the necessary adjustments and accommodations, to be compatible with existing operations. Overall, this study provides multiple new insights valuable for industrial decision-makers in making key strategic decisions regarding the adoption of LH2 aircraft technology.]]></description>
      <pubDate>Wed, 30 Apr 2025 16:58:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2540039</guid>
    </item>
    <item>
      <title>Integrating liquid hydrogen infrastructure at airports: Conclusions from an ecosystem approach at Rotterdam The Hague Airport</title>
      <link>https://trid.trb.org/View/2431723</link>
      <description><![CDATA[Aviation is a contributor to global warming. Hydrogen-powered aircraft are seen as an important option to decarbonise parts of commercial aviation. Airports have a pivotal role in facilitating the development of ground infrastructure. This paper provides a broader perspective on the supply and handling of liquid hydrogen, and necessary airport developments, to enable hydrogen-powered aviation. Hydrogen-related airport development projects at Rotterdam The Hague Airport (RTHA) are presented and discussed, and a detailed overview of the airport’s liquid hydrogen (LH2) storage facility is given. To link the ongoing developments to future needs, a LH2 demand scenario for RTHA is determined for the years 2040 and 2050. Based on this demand, analysis of levelised cost of hydrogen for relevant value chains were conducted. This study exemplifies that the LH2 value chain for an airport depends on individual characteristics of the airport and its surroundings. The hydrogen demand, the airport’s proximity to larger hydrogen hubs (import and/or production hubs) and the availability of local renewable resources, which influence electricity price and hydrogen production and liquefaction costs, are key parameters and heavily influence the airport LH2 value chain. Conceptualisation and future development of hydrogen infrastructure for airport supply should take into account the above factors. LH2 demand at RTHA in the year 2050 is predicted to range between 8–14kt. Under the given electricity price assumptions, local production and liquefaction of hydrogen at the airport is not seen as a viable option, as cost savings can be achieved by making use of the Port of Rotterdam’s large hydrogen production and import cluster nearby. The work shows that trailer-based logistics for both the delivery of LH2 to the airport and subsequent usage of these trailers in the storage and dispensing process at the airport seems the most viable for RTHA (and airports that show similarities). This further indicates that current small-scale LH2 demonstration at airports provides important lessons for scaling up.]]></description>
      <pubDate>Tue, 01 Oct 2024 09:48:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2431723</guid>
    </item>
    <item>
      <title>Multiphase-thermal flow simulation in a straight vacuum-insulated LH2 pipe: Cargo handling system in LH2 carrier</title>
      <link>https://trid.trb.org/View/2350373</link>
      <description><![CDATA[This study numerically evaluates the thermal performance of insulation materials suitable for liquid hydrogen (LH₂) transportation in pipes within a cargo handling system (CHS) of LH₂ carriers and the thermal flow characteristics of LH₂ in these pipes, using a computational fluid dynamics simulation. The design parameters of the LH₂ pipes are established based on cryogenic piping design regulations. A phase change model is employed to predict the onset of nucleate boiling (ONB) points, crucial for understanding the initial bubble formation and its impact on LH₂ flow in the pipes. The authors' findings underscore the importance of accounting for local pressure variations and their influence on boiling points. The study calculates the total volume fraction of vaporized hydrogen in the designed pipe system and assesses its safety by comparing to the lower flammability limit (LFL) of gaseous hydrogen (GH2). The results indicate that the highest vaporization occurs in cases with vacuum-only insulation. The study also estimates the length of the pipe reaching the LFL. In addition, the thermal insulation performance of six different inner filling materials, combined with vacuum insulation, is assessed by comparing the heat transfer to the pipe through the inner layer of the insulation system. Remarkably, vacuum insulation paired with a multilayer Mylar net demonstrates superior thermal performance. The outcomes of this research are anticipated to provide valuable reference material for establishing safety assessment standards in future LH₂ pipe designs.]]></description>
      <pubDate>Wed, 13 Mar 2024 17:04:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2350373</guid>
    </item>
    <item>
      <title>Energy performance evaluation of alternative energy vectors for subsonic long-range tube-wing aircraft</title>
      <link>https://trid.trb.org/View/2100434</link>
      <description><![CDATA[Decarbonising long-range aviation is challenging. This study evaluates the performance of six low-carbon fuels and their realistic impacts on aircraft design for a large long-range passenger aircraft using Breguet’s range equation. Liquid hydrogen (LH₂) and 100 % synthetic paraffin kerosene (SPK) are the only two alternative fuels found to be viable. Using present-day technology, the authors find that the design-point specific energy consumption (SEC, MJ/tonne-km) of tube-wing aircraft powered by LH₂ and 100 % SPK are 11 % higher and 0.2 % lower relative to Jet-A, respectively. At off-design points, SEC of 100 % SPK and LH₂ are always similar to and greater than Jet-A, respectively. LH₂ aircraft SEC decreases with increasing range and is less sensitive beyond 10,000 km. In a first, the authors develop an equation that enables LH₂ aircraft weight-sizing. The authors' results should inform studies on LH₂ and 100 % SPK aircraft operating costs and lifecycle emissions.]]></description>
      <pubDate>Tue, 28 Nov 2023 10:37:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2100434</guid>
    </item>
    <item>
      <title>A Feasibility Study for Quantum Computing Methodologies in Automotive Advanced Material Investigation</title>
      <link>https://trid.trb.org/View/2104513</link>
      <description><![CDATA[Regarding the calculation methodologies for future high performance computing (HPC) in variety of automotive research, quantum computing technologies are one of the promising candidate that could potentially instead conventional multi-core super computers. The functional material design, that idealize high performance electric vehicle or fuel cell electric vehicle, would be a suitable target for this novel HPC technologies. In this article, for the purpose of elucidating the practical possibility of quantum computer algorithms in future, the authors apply quantum gate simulations combining with classical molecular dynamics modelling to reproduce thermodynamic behavior of molecular composite materials. (Quantum gate simulator is as the exact simulator of quantum computer with no harmful quantum noise in limited small sized systems.) Liquid hydrogen, a potential candidate for hydrogen storage, are studied as the simplest case of this benchmark. Notable quantitative improvements of prediction performance in molecular dynamics modelling are obtained.]]></description>
      <pubDate>Thu, 23 Mar 2023 10:20:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2104513</guid>
    </item>
    <item>
      <title>Dual Use of Liquid Hydrogen in a Next-Generation PEMFC-Powered Regional Aircraft With Superconducting Propulsion</title>
      <link>https://trid.trb.org/View/2051282</link>
      <description><![CDATA[In this article, the authors present a comprehensive model framework for a disruptive cryoelectric propulsion system intended for a hydrogen-powered regional aircraft. The main innovation lies in the systematic treatment of all the electrical and thermal components to model the overall system performance. One of the main objectives is to study the feasibility of using the liquid hydrogen (LH₂) fuel to provide cryogenic cooling to the cryoelectric propulsion system and, thereby, enable ultracompact designs. Another aim has been to identify the optimal working point of the fuel cell to minimize the overall propulsion system’s mass. The full mission profile is evaluated to make the analysis as realistic as possible. Analyses are done for three different 2035 scenarios, where available data from the literature are projected to a baseline, conservative, and optimistic scenario. The results show that the total propulsion system’s power density can be as high as 1.63 kW/kg in the optimistic scenario and 0.79 kW/kg in the baseline scenario. In the optimistic scenario, there is also sufficient cryogenic cooling capacity in the hydrogen to secure proper conditions for all components, whereas the dc/dc converter falls outside the defined limit of 110 K in the baseline scenario.]]></description>
      <pubDate>Thu, 15 Dec 2022 14:15:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2051282</guid>
    </item>
    <item>
      <title>A hydrogen fuelled LH2 tanker ship design</title>
      <link>https://trid.trb.org/View/2002395</link>
      <description><![CDATA[This study provides a detailed philosophical view and evaluation of a viable design for a large liquid hydrogen tanker fuelled by liquid hydrogen. Established methods for determining tank sizing, ship stability, and ship characteristics were used to evaluate the preliminary design and performance of the liquefied hydrogen tanker named ‘JAMILA’, designed specifically to transport liquid hydrogen. JAMILA is designed around four large liquid hydrogen tanks with a total capacity of ∼280,000 m3 and uses the boil-off gas for propulsion for the loaded leg of the journey. The ship is 370 m long, 75 m wide, and draws 10.012 m at full load. It has a fully loaded displacement tonnage of 232,000 tonnes to carry 20,000 tonnes of hydrogen. Its propulsion system contains a combined-cycle gas turbine of approximately 50 MW. The volume of the hydrogen cargo pressurised to 0.5 MPa primarily determines the size and displacement of the ship.]]></description>
      <pubDate>Fri, 30 Sep 2022 14:27:30 GMT</pubDate>
      <guid>https://trid.trb.org/View/2002395</guid>
    </item>
    <item>
      <title>Scaling U.S. Zero-Emission Shipping: Potential Hydrogen Demand at Aleutian Islands Ports</title>
      <link>https://trid.trb.org/View/1987504</link>
      <description><![CDATA[The International Council on Clean Transportation (ICCT) has for several years studied the potential for liquid hydrogen (LH₂), produced using renewable electricity, to fuel transpacific container ships. The authors of this Working Paper have calculated that container shipping could yield an annual demand for more than 730,000 tonnes of LH₂ at Pacific ports. The authors study the potential role of Alaska’s Aleutian Islands ports. The authors estimate latent demand from the fishing fleet using the Port of Dutch Harbor, one of the nation’s busiest fishing ports, and the demand from hydrogen-powered transpacific vessels needing an additional refueling stop. This requires new methods to represent fishing vessels’ operations and fuel consumption, which up to now have been inadequately presented. Hydrogen-fueled ships could create a large demand for LH₂ at Aleutian Islands ports. The latent demand is around 10,000 tonnes annually, with a market value of $39 million at assumed 2035 prices. Most of the latent demand is from fishing vessels, and the authors have found that their energy consumption is about 25% higher than previously estimated. In a scenario where transpacific vessels stop at Aleutian ports, the authors find a potential demand of up to 260,000 tonnes, valued at $1 billion. An even larger market of up to $1.6 billion could be secured with maximum early LH₂ adoption, with funding of infrastructure for LH₂ bunkering at Aleutian ports. Because of Alaska’s favorable geography, the great latent LH₂ demand, and renewable energy potential, there is a strong case for federal funding to implement hydrogen bunkering at Aleutian ports. The funding could come from federal programs such as the $2.25 billion marked for port development under the 2021 Bipartisan Infrastructure Law.]]></description>
      <pubDate>Mon, 29 Aug 2022 09:27:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/1987504</guid>
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