Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “CHAINS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A systems engineering framework for the optimization of food supply chains under circular economy considerations

The current linear “take-make-waste-extractive” model leads to the depletion of natural resources and environmental degradation. Circular Economy (CE) aims to address these impacts by building supply chains that are restorative, regenerative, and environmentally benign. This can be achieved through the re-utilization of products and materials, the extensive usage of renewable energy sources, and ultimately by closing any open material loops. Such a transition towards environmental, economic and social advancements requires analytical tools for quantitative evaluation of the alternative pathways. Here, in this work, we present a novel CE system engineering framework and decision-making tool for the modeling and optimization of food supply chains. First, the alternative pathways for the production of the desired product and the valorization of wastes and by-products are identified. Then, a Resource-Task-Network representation that captures all these pathways is utilized, based on which a mixed-integer linear programming model is developed. This approach allows the holistic modeling and optimization of the entire food supply chain, taking into account any of its special characteristics, potential constraints as well as different objectives. Considering that typically CE introduces multiple, often conflicting objectives, we deploy here a multi-objective optimization strategy for trade-off analysis. A representative case study for the supply chain of coffee is discussed, illustrating the steps and the applicability of the framework. Single and multi-objective optimization formulations under five different coffee-product demand scenarios are presented. The production of instant coffee as the only final product is shown to be the least energy and environmental efficient scenario. On the contrary, the production solely of whole beans sets a hypothetical upper bound on the optimal energy and environmental utilization. In both problems presented, the amount of energy generated is significant due to the utilization of waste generated for the production of excess energy.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Chlorination of Side Chains: A Strategy for Achieving a High Open Circuit Voltage Over 1.0 V in Benzo[1,2-b:4,5-b']dithiophene-Based Non-Fullerene Solar Cells

Here, a benzo[1,2-b:4,5-b']dithiophene-based donor material with chlorine atoms substituted on its side chains, named PBClT, was designed and developed for application in non-fullerene solar cells to enhance the open-circuit voltage ( V oc ) without decreasing charge carrier transfer in the corresponding blend films. The results demonstrated that the chlorinated PBClT polymer was an efficient donor in non-fullerene polymer solar cells (PSCs) and exhibited a blue-shifted absorbance, resulting in more complementary light absorption with non-fullerene acceptors, such as ITIC. In addition, the chlorine substitution decreased the HOMO level of PBClT, and as a result, the V oc of the corresponding solar cell increased dramatically to 1.01 V, which is much higher than that of the non-chlorine analog, PTB7-Th, with a V oc of approximately 0.82 V. The 2D-GIWAX results illustrated that the PBClT/ITIC blend film exhibited a “face-on” orientation, which suggested that the chlorine substituents on the side chains favored π-π stacking in the direction perpendicular to the electron flow in photovoltaic devices. Furthermore, the PBClT/ITIC blend film showed a π-π stacking distance of 3.85 Å, which was very close to that of its non-chlorine analog blend film with a distance of approximately 3.74 Å. Based on this result, the introduction of multiple chlorine atoms on the conjugated side chains not only adjusted the energy level of the low-band-gap polymer through the electron withdrawing ability of the chlorine atoms but also subtly avoided obvious morphological changes that could result from strong steric hindrance in the main chain of the polymers. The PBClT/ITIC-based PSCs exhibited a maximum PCE of 8.46% with a V oc of 1.01 V, which is an increase in the PCE of approximately 22% compared to the PTB7-Th-based device based on our parallel experiments.

14 SOLAR ENERGY↗
DOE OSTI2018

Alkyl Chain End Group Engineering of Small Molecule Acceptors for Non-Fullerene Organic Solar Cells

Alkyl chain engineering is widely used to prepare high-performance donor materials. However, relatively few studies have been focused on the alkyl chain optimization of acceptor materials. Herein, a series of new A-D-A (acceptor-donor-acceptor) type small molecule acceptors (ITBTR-C2, ITBTR-C4, ITBTR-C6, and ITBTR-C8) with indacenodithieno[3,2-b]thiophene (IDTT) as the core, benzothiadiazole (BT) as the π bridge, and ethyl-, butyl-, hexyl-, and octyl-substituted 2-(1,1-dicyanomethylene) rhodanine as the end groups, respectively, are successfully synthesized to systematically investigate the alkyl substituent effects on the physical, chemical, and electronic properties of A-D-A type small molecule acceptors. All molecules exhibit a strong and broad absorption from 600 to 800 nm as well as similar HOMO and LUMO energy levels. ITBTR-C6 with hexyl substitution showed the highest electron mobility and better phase separation morphology after blending with a donor polymer (PBDB-T). Therefore, inverted bulk heterojunction organic solar cells based on ITBTR-C6:PBDB-T blends exhibit the highest power conversion efficiency (PCE) of 8.26% with an open-circuit voltage ( V OC ) of 0.89 V, a high short-circuit current density ( J SC ) of 15.80 mA/cm2, and a fill factor (FF) of 58.21%, while the PCEs of ITBTR-C2-, ITBTR-C4-, and ITBTR-C8-based devices are 7.04%, 7.43%, and 7.93%, respectively. After solvent vapor and thermal annealing, both the J SC and FF values of the ITBTR-C6-based device further increased, leading to a PCE of 9.29%. Furthermore, the results demonstrate that the alkyl chain substitution of A-D-A type small molecule acceptors is critical, and an appropriate adjustment of the alkyl chains can effectively enhance device performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Poly(lactic acid) Toughening through Chain End Engineering

The intrinsic brittleness of poly(lactic acid) (PLA) has hindered its widespread use in many structural applications. Various strategies have been developed to toughen PLA; however, most of the methods lead to a trade-off in strength or modulus. In this study, a chain end engineering strategy was developed to toughen PLA via an industry-friendly melt processing method. Green acids with multifunctional groups, such as 1,2,3,4-butanetetracarboxylic acid (BTCA), were used to modify PLA chain ends/tails via a melt reaction. We report a remarkable improvement in toughness (16×) was achieved by the addition of a minimal amount of BTCA (0.5%). At the same time, the toughened PLA samples maintained the tensile strength and Young’s modulus of neat PLA, suggesting a unique toughening mechanism that is different from the plasticizing effect. Other acid–based modifiers with different numbers of functional groups were also studied in this work. To understand the toughening, we propose a chain end engineering picture that can improve the toughness via a reduction in the number density of chain ends or defects of entanglement and the formation of long-branch topological structures. This study demonstrates a unique and cost-effective strategy for toughening PLA via scalable melt reaction without sacrificing other mechanical properties of PLA, potentially broadening the applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Water Chain Formation on TiO{sub 2}(110)

The adsorption of water on a reduced rutile TiO{sub 2}(110)-(1×1) surface has been investigated using scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. The STM measurements show that at a temperature of 50 K, an isolated water monomer adsorbs on top of a Ti(5f) atom on the Ti row in agreement with earlier studies. As the coverage increases, water molecules start to form one-dimensional chain structures along the Ti row direction. Supporting DFT calculations show that the formation of an H-bonded one-dimensional water chain is energetically favorable compared to monomer adsorption. In the chain, there are H-bonds between adjacent water molecules, and the water molecules also form H-bonds to neighboring bridging oxygens of TiO{sub 2}(110). Thermal annealing at T = 190 K leads to the formation of longer chains facilitated by the diffusion of water on the surface. The results provide insight into the nature of the hydrogen bonding in the initial stage of wetting of TiO{sub 2}.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Insight from molecular modelling: does the polymer side chain length matter for transport properties of perfluorosulfonic acid membranes?

We present a detailed analysis of the nanostructure of short side chain (SSC) perfluorosulfonic acid membrane and its effect on H{sub 2}O network percolation, H{sub 3}O{sup +} and H{sub 2}O diffusion, and mean residence times of H{sub 3}O{sup +} and H{sub 2}O near SO{sub 3}{sup -} groups based on molecular dynamics simulations. We studied a range of hydration levels ({lambda}) at temperatures of 300 and 360 K, and compare the results to our previous findings in the benchmark Nafion membrane at 300 K. The water channel diameter is about 20% larger in Nafion, while the extent of SO3- clustering is more in SSC membrane. The calculated channel diameter is in excellent agreement with the recently proposed cylindrical water channel model of these membranes. The H{sub 2}O network percolation occurs at comparable hydration levels, and the diffusion coefficients of H{sub 2}O and H{sub 3}O{sup +} are similar in SSC and Nafion membranes. Raising the temperature of the SSC membrane from 300 to 360 K provides a much bigger increase in proton vehicular diffusion coefficient (by a factor of about 4) than changing the side chain length. H3O+ ions are found to exchange more frequently with SO{sub 3}{sup -} partners at the higher temperature. Our key findings are that (a) the hydrophobic-hydrophilic separation in the two membranes is surprisingly similar; (b) at all hydration levels studied, the longer side chain of Nafion is bent and is effectively equivalent to a short side chain in terms of extension into the water domain; and (c) proton transport along the centre of the channel is improbable and vehicular proton transport occurs between SO{sub 3}{sup -} groups. The simulations are validated by good agreement with corresponding experimental values for the simulated membrane density and diffusion coefficients of H{sub 2}O.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2015

From 1D chain to 3D network: A theoretical study on TiO{sub 2} low dimensional structures

We have performed a systematic study on a series of low dimensional TiO{sub 2} nanostructures under density functional theory methods. The geometries, stabilities, growth mechanism, and electronic structures of 1D chain, 2D ring, 2D ring array, and 3D network of TiO{sub 2} nanostructures are analyzed. Based on the Ti{sub 2}O{sub 4} building unit, a series of 1D TiO{sub 2} nano chains and rings can be built. Furthermore, 2D ring array and 3D network nanostructures can be constructed from 1D chains and rings. Among non-periodic TiO{sub 2} chain and ring structures, one series of ring structures is found to be more stable. The geometry model of the 2D ring arrays and 3D network structures in this work has provided a theoretical understanding on the structure information in experiments. Based on these semiconductive low dimensional structures, moreover, it can help to understand and design new hierarchical TiO{sub 2} nanostructure in the future.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Coffee supply chain planning under climate change

The growing demand but uncertain supply makes the sustainability of the coffee industry a shared concern for all participants along the coffee supply chain. This study proposed a decision-making model that comprises the cultivation management, including shade management and annual agriculture management, and the supply chain logistics. A two-stage stochastic program is presented and used within a rolling horizon scheme that periodically updates input data information to deal with uncertainty associated with future climate scenarios. The program minimizes the total expected cost of the entire supply chain of arabica coffee. The study applied the model to the real case study of arabica coffee bean supply to the U.S. market, trying to answer whether arabica coffee supply can meet the U.S. demand from 2022 to 2050 and how to best mitigate any shortage through corporate-farmer partnerships. The results show that the coffee supply will have a 3% shortage in the future; medium-level shade management and more irrigation and fertilization are possible mitigation strategies. These results demonstrate the need for all participants to adopt suitable technologies for the sustainability of global coffee supply chains together.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Spinon continuum in the Heisenberg quantum chain compound Sr 2 ⁢V 3 ⁢O 9

Magnetic excitations in the spin chain candidate Sr 2 ⁢V 3 ⁢O 9 have been investigated by inelastic neutron scattering on a single crystal sample. A spinon continuum with a bandwidth of ~22 meV is observed along the chain formed by alternating magnetic V 4+ and nonmagnetic V 5+ ions, which reveals the importance of the orbital degree of freedom in determining the chain axis as identified by prior electronic structure calculations. Incipient magnetic Bragg peaks due to weak ferromagnetic interchain couplings emerge when approaching the magnetic transition at T N ~ 5.3 K, while the excitations remain gapless within the instrumental resolution. Comparisons to the Bethe ansatz, density matrix renormalization group calculations, and effective field theories confirm Sr 2 ⁢V 3 ⁢O 9 as a host of weakly coupled S = 1/2 chains dominated by antiferromagnetic intrachain interactions of ~7.1(1) meV.

1-dimensional spin chains↗
DOE OSTI2018

Green Design of a Cellulosic Butanol Supply Chain Network: A Case Study of Sorghum Stem Bio-butanol in Missouri

Cellulosic butanol is a very promising renewable fuel to consider for the future transportation market. However, the seasonal availability of the raw materials, high maintenance cost, and high logistical cost of the biomass energy supply chain are the main factors impeding the commercialization and large-scale-production of this energy source. Furthermore, research focusing on an environmental or green supply chain network design of cellulosic butanol has been insufficient. Here, this study focused on designing a green supply chain network for cellulosic butanol. A life cycle analysis was integrated into a multi-objective linear programming model to optimize the cellulosic butanol supply chain network. With the objectives of maximizing the economic profits and minimizing the greenhouse gas emissions, the proposed model can optimize the location and size of a bio-butanol production plant. The mathematical model was applied to a case study in the state of Missouri, and solved the tradeoff between the feedstock and market availabilities of sorghum stem bio-butanol.

09 BIOMASS FUELS↗
DOE OSTI2025

Securing the Modern Grid: Federal Investments, Digitization, and Supply Chain Strategy

Across the United States (U.S.) grid expansion and modernization is underway, paving the way for accelerated load growth and intelligent resource management. Digitization of the grid is supported by several state and federal programs, providing support for utilities installing advanced metering infrastructure (AMI), AI-powered analytics systems, battery energy storage systems (BESS), and distributed energy resource management systems (DERMS) to transform the grid from a one-way power delivery system into an intelligent, responsive network that will enable faster load growth and power expansion of data centers for advanced artificial intelligence (AI) applications. The digital transformation of America's grid presents opportunity for increased efficiency and resiliency but also introduces new digital risks that require careful management. Digital equipment often contains several vulnerabilities such as unencrypted communication protocols, and persistent remote access capabilities that could be exploited to manipulate device settings, coordinate service disruptions, or inject false data into grid operations. These digital risks become particularly important as the grid must rapidly scale to support AI-driven data centers, which the administration has identified as essential for maintaining U.S. technological leadership and economic competitiveness. These vulnerabilities are compounded by supply chain realities: Chinese manufacturers currently produce 70-90% of essential grid components including inverters, batteries, and control systems, with the U.S. lacking domestic manufacturing capacity for critical assets like extra-high voltage transformers. Recent federal legislation has established Foreign Entity of Concern (FEOC) restrictions to address these risks, requiring projects to achieve escalating thresholds of non-FEOC content to receive tax credits while utilities work to expand sourcing channels for their supply chains and strengthen security measures. These restrictions arrive precisely when utilities face unprecedented electricity demand growth driven by the rapid growth in data centers, creating a considerable challenge: rapidly expanding infrastructure while navigating complex compliance requirements while lacking viable alternatives for many critical components. Idaho National Laboratory (INL) and its partners have developed practical approaches to help utilities navigate these intersecting challenges as they leverage federal investment to strengthen and grow the grid. These solutions include Cyber-Informed Engineering (CIE) principles that build resilience directly into systems, the Cirrus tool for secure cloud migration, and enhanced procurement guidance that embeds security requirements throughout equipment lifecycles. Federal initiatives, such as the Technical Assistance for Digital Assurance (TADA) project, provide direct support to utilities implementing these approaches while facilitating knowledge sharing across the industry. While these tools and frameworks cannot eliminate all risks inherent in foreign supply chain dependencies, they offer pragmatic pathways for strengthening security posture without sacrificing the deployment momentum essential to meeting surging electricity demand. Ultimately, securing America's digital energy infrastructure demands dedicated coordination across multiple fronts: building domestic supply chains, implementing robust digital assurance practices, and maintaining the aggressive modernization timeline necessary for reliability, resilience, and energy independence.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2025

Potential Supply Chain and Cost Reduction Strategies for Advanced Nuclear Reactors

This milestone represents a level of effort to provide recommendations for a supply chain plan and establish relationships between advanced reactor companies and large companies in the oil & gas and chemical industries. It represents a starting point to develop the plan with options, general equipment lists, and rough associated cost estimates of major equipment and the associated systems needed. This effort will provide an opportunity to leverage the experience that oil & gas and chemicals companies possess in large capital equipment procurement, modularization, acquisition and installation. Potential supply chain solutions will be discussed and preliminary options for worldwide manufacturers will be elucidated. The goal of this effort will be to leverage the years of accumulated experience in the oil & gas and chemical industries in the area of capital equipment acquisition to understand the potential supply chain options and to reduce potential acquisition costs by optimizing the supply chain options for advanced nuclear reactor modularization, manufacturing and acquisition.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2007

The NASA Human Space Flight Supply Chain, Current and Future

The current NASA Human Space Flight transportation system, the Space Shuttle, is scheduled for final flight in 2010. The Exploration initiative will create a new capability with a combination of existing systems and new flight and ground elements. To fully understand and act on the implications of such change it is necessary to understand what, how, when and where such changes occur and more importantly, how all these interact. This paper presents Human Space Flight, with an emphasis on KSC Launch and Landing, as a Supply Chain of both information and materials. A supply chain methodology for understanding the flow of information and materials is presented. Further, modeling and simulation projects funded by the Exploration initiative to understand the NASA Exploration Supply Chain are explained. Key concepts and their purpose, including the Enterprise, Locations, Physical and Organizational Functional Units, Products, and Resources, are explained. It is shown that the art, science and perspective of Supply Chain Management is not only applicable to such a government & contractor operation, it is also an invaluable approach for understanding, focusing improvement and growth. It is shown that such commercial practice applies to Human Space Flight and is invaluable towards one day creating routine, affordable access to and from space.

supply chain managemen↗
NASA NTRS2019

Utilizing Supply Chain Assessments to Achieve Excellence, Reduce Risks and Improve Processes

Utilizing Supply Chain Assessments to Achieve Excellence, Reduce Risks and Improve Processes Supply Chain Management: Why it is important Strategic Challenge: Supply Chain RisksHistory of supply chain assessments at GoddardExamining case studies on successes and lessons learnedEnabling teams to develop tools to manage GSFC supply chainGaining supplier insight through IT tools that combines supplier data and provides supplier alerts

Risk Management↗
DOE OSTI2018

Blockchain: Next Generation Supply Chain Security for Energy Infrastructure and NERC Critical Infrastructure Protection (CIP) Compliance

The U.S. power grid is a complex system of systems that requires a secure, reliable and trustworthy global supply chain. This is especially true for the grid’s increasing number of networked energy delivery system (EDS) and industrial control systems (ICS) and associated vendors, distributers, integrators and end users. Grid modernization has increased the use of “smart” energy devices that network, digitize, automate and increasingly converge the cyber-physical energy supply chain. In this Energy Internet of Things (EIoT) environment there is an increasing number of both critical cyber assets as well as data speed and size requirements, creating new cyber supply chain security and North American Electric Reliability Corporation (NERC) CIP compliance challenges for utilities, regulators and vendors. In realization of these goals, improvements are needed in the process and technology to better monitor, audit and realize cyber security and compliance goals in complex EIoT environments. This paper explores how blockchain technology may present a disruptive solution to facilitate NERC CIP compliance and increase the security of the electricity infrastructure supply chain through a cryptographically signed distributed ledger that provides increased data provenance, attribution and auditability.

Blockchain, Cyber security, grid cyber, NERC CIP, ↗
DOE OSTI2019

Impact of Li-Ion Battery Recycling on the Supply Chain

With the increasing demand of the lithium ion batteries (LIB), it is expected that supply of some critical metals used in Li-ion batteries such as cobalt and lithium will fall short in the near-term, or their prices could increase significantly in response to the high demand. Besides increasing mining and production activities, we believe that a closed-loop system with recycling at the end-of-life provides a pathway to lower environmental impacts and a source of high value materials that can be used in producing new batteries. This presentation reviews the current state of the LIB manufacturing supply chain, discuses evolution and supply chain issues for cathode and anode materials, addresses some issues associated with battery end-of-life, and sheds light on the importance of LIB recycling from the environmental and value chain perspectives. This presentation also discusses the expected benefits of recycling on the global LIB supply chain.

25 ENERGY STORAGE↗
DOE OSTI2021

Supporting the Li-Ion Battery Supply Chain via PEV Battery Reuse

The electric vehicle market is growing rapidly and there is significant need for lithium ion batteries and their materials. There is growing concern about the supply chain issues of lithium ion batteries in the US as most of the materials and components come from overseas. The concern about supply chain would be even more of a concern as more lithium ion systems will be installed in the renewable grid. By 2025, it is estimated that 3.5 million used PEVs may be retiring worldwide with commutative capacity of around 150 GWh. The question is what the is best way to deal with these batteries: recycle them right away for re-introduction of valuable materials into the battery supply chain or reused and then recycle them. These batteries usually have between 70-80% of their original capacity and studies have shown second use of these batteries are technically and environmentally – the question has been the economic viability. Most of LIBs has been going into the growing electric vehicle market. Rather than using new LIBs in the future grid, the second-life batteries is a significant resource and could alleviate supply chain issues.

47 OTHER INSTRUMENTATION↗
DOE OSTI2024

Developing a Supply Chain Security Program

Amid growing concerns over foreign manufacturing for components and devices deployed in critical energy infrastructure, this research from the national labs will highlight best practices for developing and maintaining a supply chain security program. Tools for asset inventory, tips for developing and maintaining software- and hardware-bills-of-materials (SBOMs and HBOMs), recommended contractual language for vendor agreements, and identification of responsibilities will be shared. We discuss the one-time requirements to enable a successful supply chain security program and the best ways to operationalize this program for maximum impact, including development of robust practices for vulnerability tracking, patch management, and workarounds, with understanding of the reliability and uptime requirements for utilities. The recommendations shared are based on a cyber-informed engineering approach to identification of high-consequence impacts and the engineering controls related to supply chain management that can best mitigate these impacts. This approach allows for prioritization of resources. Additionally, we highlight relative up-front and ongoing costs associated with recommended controls. Viewers will leave with an understanding what a supply chain security program is, and what steps, prioritized for resource-constrained organizations, can build a robust program.

14 SOLAR ENERGY↗