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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.

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At least 919 records · Page 51

Harnessing Ocean Thermal Gradients Using Thermoelectric Based Submersibles for Ocean Power Applications

The urgent need for energy solutions in marine environments has accelerated the development of innovative technologies capable of leveraging natural resources for power generation. This study introduces a buoyancy-driven submersible system designed to harness ocean thermal gradients using thermoelectric generators (TEGs) and phase change materials (PCMs). The technology aims to provide autonomous power to offshore aquaculture farms, unmanned underwater vehicles (UUVs), offshore platform illumination, and ocean sensors, significantly reducing dependence on fossil fuels. Ocean thermal gradients, especially prevalent in mid-latitude regions, exhibit temperature differences between surface and deep waters ranging from 7 degrees Celsius to 30 degrees Celsius depending on seasonal variations. The proposed submersible technology utilizes TEGs to convert thermal energy from these gradients into electrical power, generating between 0.2 and 0.5 watts, while PCMs are employed to store and regulate this energy, ensuring a stable and continuous power supply. The buoyancy-driven mechanism of the submersible enhances its capability to navigate through varying depths, optimizing its exposure to different thermal gradients and maximizing energy harvesting. The performance of this submersible system is analyzed through detailed thermodynamic assessments and computational fluid dynamics (CFD) modeling focused on heat transfer. These analyzes consider real-world ocean temperature profiles and seek to refine the interaction between TEGs and PCMs to optimize energy extraction. The evaluation encompasses several key performance metrics, including power output and energy efficiency. Results confirm the potential of this innovative technology to provide a continuous and reliable power source for marine applications. By demonstrating the feasibility of using ocean thermal gradients for energy generation, this study contributes to the broader efforts of innovation in energy technologies for harsh, remote marine environments. The implementation of such promises is significant advancements in the autonomy of marine operations. The ongoing research will further investigate scalability ensuring that the system can be effectively adapted to various marine settings and operational demands.

16 TIDAL AND WAVE POWER↗

Evolution_and_engineering_of_pathways_for_aromatic_O-demethylation_in_Pseudomonas_putida_KT2440

Biological conversion of lignin from biomass offers a promising strategy for sustainable production of fuels and chemicals. However,aromatic compoundsderived from lignin commonly contain methoxy groups, andO-demethylation of these substrates is often a rate-limiting reaction that influences catabolic efficiency. Severalenzymefamilies catalyze aromaticO-demethylation, but they are rarely comparedin vivoto determine an optimal biocatalytic strategy. Here, two pathways for aromaticO-demethylation were compared inPseudomonas putidaKT2440. The native Rieske non-heme ironmonooxygenase(VanAB) and, separately, a heterologous tetrahydrofolate-dependentdemethylase(LigM) were constitutively expressed inP. putida, and the strains were optimized via adaptive laboratory evolution (ALE) withvanillateas a model substrate. All evolved strains displayed improved growth phenotypes, with the evolved strains harboring the native VanAB pathway exhibiting growth rates ∼1.8x faster than those harboring the heterologous LigM pathway.Enzyme kineticsandtranscriptomicsstudies investigated the contribution of selected mutations toward enhanced utilization of vanillate. The VanAB-overexpressing strains contained the most impactful mutations, including those in VanB, thereductasefor vanillateO-demethylase, PP_3494, a global regulator of vanillate catabolism, andfghA, involved in formaldehydedetoxification. These three mutations were combined into a single strain, which exhibited approximately 5x faster vanillate consumption than the wild-type strain in the first 8 h of cultivation. Overall, this study illuminates the details of vanillate catabolism in the context of two distinct enzymatic mechanisms,yielding a platform strain for efficientO-demethylation of lignin-related aromatic compounds to value-added products. This DOI contains supplementary material associated with the published manuscript.

CBI↗

Design, operation, and critical issues of the U.S. Space Station Freedom propulsion system

The U.S. Space Station Freedom Manned Base (SSFMB) propulsion system is a gaseous hydrogen/oxygen-based system for primary reboost, attitude control, and station contingencies using electrolyzed water as a propellant. A secondary propulsion reboost system employs multipropellant resistojets which utilize the various waste gases generated during normal station operations. The hydrogen/oxygen propulsion system is comprised of several modules which contain thrusters, propellant storage tanks, regulation subsystems, water electrolysis units, electronic controls, and fluid plumbing. The resistojet system is comprised of one module containing the resistojets, regulators, electronic controls, and fluid plumbing. The waste gas propellant storage takes place in the Fluid Management System.

Morano, Joseph S.↗

Autonomous Intelligent Charging/Discharging of Electric Vehicles using Distributed Multi-Agent ADMM Framework for Grid Ancillary Services

The increasing popularity of Electric Vehicles (EVs) in the distribution grid along with technological advancement in EV electronics such as vehicle to grid (V2G) technique has enabled them to participate in grid ancillary services. To achieve this, the EVs need to establish a contract with third-party aggregators and connect to a charging unit, either residential or commercial. At any time they are connected, the EVs can decide to take part in the ancillary services program offered to them by the aggregators. If agreed, the aggregators will use the EVs as a power source capable of charging/discharging power according to the input signal, and in return, they will be compensated. This inter-temporal nature of charging/discharging is also transforming the traditional optimal power flow (OPF) problem into a dynamic OPF problem. This chapter aims at developing a multi-layer time-dependent optimization algorithm to utilize EV potential and provide ancillary services while maximizing its utilization function. Specifically, in the upper layer, an autonomous distributed ADMM algorithm is developed to optimize the cost for charging/discharging EVs while using them to regulate the voltage at each bus in the distribution grid. The distributed ADMM algorithm is also expanded to the lower layer where the individual EVs active and reactive power is controlled for voltage regulation while maintaining the desired state of the charge of the vehicle at the end of the charging period. Here, the effectiveness and performance improvement of the proposed multi-layer algorithm is illustrated through analytical analysis and simulation results.

Rahman, Towfiq↗

Autonomous Intelligent Charging/Discharging of Electric Vehicles using Distributed Multi-Agent ADMM Framework for Grid Ancillary Services

The increasing popularity of Electric Vehicles (EVs) in the distribution grid along with technological advancement in EV electronics such as vehicle to grid (V2G) technique has enabled them to participate in grid ancillary services. To achieve this, the EVs need to establish a contract with third-party aggregators and connect to a charging unit, either residential or commercial. At any time they are connected, the EVs can decide to take part in the ancillary services program offered to them by the aggregators. If agreed, the aggregators will use the EVs as a power source capable of charging/discharging power according to the input signal, and in return, they will be compensated. This inter-temporal nature of charging/discharging is also transforming the traditional optimal power flow (OPF) problem into a dynamic OPF problem. This chapter aims at developing a multi-layer time-dependent optimization algorithm to utilize EV potential and provide ancillary services while maximizing its utilization function. Specifically, in the upper layer, an autonomous distributed ADMM algorithm is developed to optimize the cost for charging/discharging EVs while using them to regulate the voltage at each bus in the distribution grid. The distributed ADMM algorithm is also expanded to the lower layer where the individual EVs active and reactive power is controlled for voltage regulation while maintaining the desired state of the charge of the vehicle at the end of the charging period. The effectiveness and performance improvement of the proposed multi-layer algorithm is illustrated through analytical analysis and simulation results.

Rahman, Towfiq↗

Development of dual‐inducible duet‐expression vectors for tunable gene expression control and CRISPR interference‐based gene repression in Pseudomonas putida KT2440

Summary The development of P. putida as an industrial host requires a sophisticated molecular toolbox for strain improvement, including vectors for gene expression and repression. To augment existing expression plasmids for metabolic engineering, we developed a series of dual‐inducible duet‐expression vectors for P. putida KT2440. A number of inducible promoters (P lac , P tac , P tetR/tetA and P bad ) were used in different combinations to differentially regulate the expression of individual genes. Protein expression was evaluated by measuring the fluorescence of reporter proteins (GFP and RFP). Our experiments demonstrated the use of compatible plasmids, a useful approach to coexpress multiple genes in P. putida KT2440. These duet vectors were modified to generate a fully inducible CRISPR interference system using two catalytically inactive Cas9 variants from S. pasteurianus (dCas9) and S. pyogenes (spdCas9). The utility of developed CRISPRi system(s) was demonstrated by repressing the expression of nine conditionally essential genes, resulting in growth impairment and prolonged lag phase for P. putida KT2440 growth on glucose. Furthermore, the system was shown to be tightly regulated, tunable and to provide a simple way to identify essential genes with an observable phenotype.

59 BASIC BIOLOGICAL SCIENCES↗

Light Regimes Shape Utilization of Extracellular Organic C and N in a Cyanobacterial Biofilm

ABSTRACT Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph organic matter consumption. Cyanobacteria in phototrophic biofilms can reuse extracellular organic carbon, but the metabolic drivers of extracellular processes are surprisingly complex. We investigated the metabolic foundations of organic matter reuse by comparing exoproteome composition and incorporation of 13 C-labeled and 15 N-labeled cyanobacterial extracellular organic matter (EOM) in a unicyanobacterial biofilm incubated using different light regimes. In the light and the dark, cyanobacterial direct organic C assimilation accounted for 32% and 43%, respectively, of all organic C assimilation in the community. Under photosynthesis conditions, we measured increased excretion of extracellular polymeric substances (EPS) and proteins involved in micronutrient transport, suggesting that requirements for micronutrients may drive EOM assimilation during daylight hours. This interpretation was supported by photosynthesis inhibition experiments, in which cyanobacteria incorporated N-rich EOM-derived material. In contrast, under dark, C-starved conditions, cyanobacteria incorporated C-rich EOM-derived organic matter, decreased excretion of EPS, and showed an increased abundance of degradative exoproteins, demonstrating the use of the extracellular domain for C storage. Sequence-structure modeling of one of these exoproteins predicted a specific hydrolytic activity that was subsequently detected, confirming increased EOM degradation in the dark. Associated heterotrophic bacteria increased in abundance and upregulated transport proteins under dark relative to light conditions. Taken together, our results indicate that biofilm cyanobacteria are successful competitors for organic C and N and that cyanobacterial nutrient and energy requirements control the use of EOM. IMPORTANCE Cyanobacteria are globally distributed primary producers, and the fate of their fixed C influences microbial biogeochemical cycling. This fate is complicated by cyanobacterial degradation and assimilation of organic matter, but because cyanobacteria are assumed to be poor competitors for organic matter consumption, regulation of this process is not well tested. In mats and biofilms, this is especially relevant because cyanobacteria produce an extensive organic extracellular matrix, providing the community with a rich source of nutrients. Light is a well-known regulator of cyanobacterial metabolism, so we characterized the effects of light availability on the incorporation of organic matter. Using stable isotope tracing at the single-cell level, we quantified photoautotroph assimilation under different metabolic conditions and integrated the results with proteomics to elucidate metabolic status. We found that cyanobacteria effectively compete for organic matter in the light and the dark and that nutrient requirements and community interactions contribute to cycling of extracellular organic matter.

09 BIOMASS FUELS↗

Global Regulations for Sustainable Battery Recycling: Challenges and Opportunities

With the rapid expansion of transportation electrification worldwide, the demand for electric vehicles (EVs) has increased dramatically, creating new and sustainable growth opportunities for the global economy. However, as the most expensive component of EVs, lithium-ion batteries pose significant sustainability challenges due to raw material consumption and supply chain constrains, as well as the complexities of end-of-life battery disposal and recycling. To address these concerns, many countries are actively establishing regulations to promote sustainable pathways for battery reuse and recycling. Despite these efforts, existing battery recycling regulations remain often inefficient and vary significantly across different countries in legal enforcement, producer responsibility, waste classification, recycling targets, design standards, public engagement, and financial incentives, particularly given the complexities of the global supply chain and resource distribution within the battery industry. Understanding these regulatory differences and establishing a unified framework are therefore crucial to ensuring sustainable and efficient battery recycling. This review provides a comprehensive analysis of the necessity of establishing robust regulations for sustainable development of battery recycling industry. The evolution and refinement of battery recycling regulations are deeply reviewed to identifying persistent gaps and challenges in key countries. Furthermore, we discuss the challenges associated with regulatory enforcement and propose strategies for developing a more cohesive legislative framework to ensure the effective utilization of retired batteries.

25 ENERGY STORAGE↗

Vehicle Efficiency and Tractive Work: Rate of Change for the Past Decade and Accelerated Progress Required for U.S. Fuel Economy and CO 2 Regulations

A major driving force for change in light-duty vehicle design and technology is the National Highway Traffic Safety Administration (NHTSA) and the U.S. Environmental Protection Agency (EPA) joint final rules concerning Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) emissions for model years (MY) 2016 through 2025 passenger cars and light trucks. The chief goal of this current study is to compare the already rapid pace of fuel economy improvement and technological change over the previous decade to the needed rate of change to meet regulations over the next decade. EPA and NHTSA comparisons of the MY 2004 US light-duty vehicle fleet to the MY 2014 fleet shows improved fuel economy (FE) of approximately 28% using the same FE estimating method mandated for CAFE regulations. Future predictions by EPA and NHTSA concerning ensemble fleet fuel economy are examined as an indicator of needed vehicle rate-of-change. A set of 40 same-model vehicle pairs for MY 2005 and MY 2015 is compared to examine changes in energy use and related technological change over the 10 year period. Powertrain improvements measured as increased vehicle efficiency, and vehicle mass-glider improvements measured as decreased tractive work requirements are quantified. The focus is first on conventional gasoline powertrain vehicles which currently dominate the market, with hybrids also examined due to their high potential importance for CAFE compliance. Most hybrid vehicles with significant sales in 2014 were represented in the study. Results show 10 years of progress for the studied vehicle set includes lowered tractive effort of about 5.6% and improved powertrain efficiency of about 16.5%. Further analysis shows that this high rate of past progress must increase by about 50% in order to meet the 2025 CAFE standards. Examination of where certain MY 2015 vehicle compare to CAFE regulations is offered as well as some simple conjecture on what is needed to meet regulations under reasonable assumptions.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

A Cross‐Linked Flexible Metaferroelectrolyte Regulated by 2D/2D Perovskite Heterostructures for High‐Performance Compact Solid‐State Sodium Batteries

Abstract To address the issues of limited ionic conductivity and poor interface stability at room and low temperatures in solid‐state electrolytes, a robust intrinsic ferroelectrolyte or nanoferroelectrolyte strategy for engineering solid‐state flexible ferroelectric composite electrolytes utilizing strongly coupled intrinsic ion conducting 2D/2D sodium‐rich anti‐perovskite (NaRAP)/ferroelectric perovskite heterostructures is introduced. Herein, highly scalable PVDF‐based metaferroelectrolytes with Na 2.99 Ba 0.005 OCl/Ca 2 Na 2 Nb 5 O 16 − (CNNO − ) nanosheets into a ferroelectric poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) matrix, through an in situ cross‐linking and spontaneous bridging method, for compact solid‐state sodium batteries (SSBs), are reported. Benefiting from unique well‐dispersed 3D ferroelectric coupled network and the Na 2.99 Ba 0.005 OCl/CNNO − ‐induced PVDF‐HFP ferroelectric β phase, the Na + flux is regulated, thereby inhibiting Na dendrite growth at the interface. Notably, the optimized PH‐5% NC metaferroelectrolyte exhibits rapid ion transport (1.11 × 10 −4 S cm −1 at 25 °C), a wide electrochemical window (> 4.8V), superior conformal mechanical compatibility, improved flexibility, good elasticity and flame retardancy. The solid‐state Na 3 V 2 (PO 4 ) 3 /PH‐5% NC/Na batteries present a stable cycling performance (remaining 56.4 mAh g −1 after 500 cycles at 1 C) even at 0 °C, potential for cost‐effective, safe, stable and compact SSB energy storage over 600 Wh L −1 , vastly surpassing 365 Wh L −1 of the current commercial sodium‐ion liquid‐electrolyte batteries.

Chemistry↗

Design and Performance of Solar Decathlon 2011 High-Penetration Microgrid: Preprint

The U.S. Department of Energy Solar Decathlon challenges collegiate teams to design, build, and operate solar-powered houses that are cost-effective, energy-efficient, and attractive. The Solar Decathlon 2011 was held in Washington, D.C., from September 23 to October 2, 2011 . A high-penetration microgrid was designed, installed, and operated for the Solar Decathlon 2011 to grid-connect 19 highlyenergy-efficient, solar-powered competition houses to a single utility connection point. The capacity penetration of this microgrid (defined as maximum PV generation divided by maximum system load over a two-week period) was 74% based on 1-minute averaged data. Temporary, ground-laid conductors and electrical distribution equipment were installed to grid-connect the Solar Decathlon village,which included the houses as well as other electrical loads used by the event organizers. While 16 of the houses were connected to the 60 Hz microgrid, three houses from Belgium, China, and New Zealand were supplied with 50 Hz power. The design of the microgrid, including the connection of the houses powered by 50 Hz and a standby diesel generator, is discussed in this paper. In addition to theutility-supplied net energy meters at each house, a microgrid monitoring system was installed to measure and record energy consumption and PV energy production at 1-second intervals at each house. Bidirectional electronic voltage regulators were installed for groups of competition houses, which held the service voltage at each house to acceptable levels. The design and successful performance ofthis high-penetration microgrid is presented from the house, microgrid operator, and utility perspectives.

14 SOLAR ENERGY↗

Carbon Capture, Utilization, and Sequestration: Technology and Policy Status and Opportunities

This paper examines the present state of CCUS and the challenges to widespread deployment in the energy sector. It explores the policy and technology environment for coal-fired power generation and CCUS for energy and industrial uses. It offers an array of actions policymakers and regulators can use to encourage CCUS adoption to extend the life of existing coal-fired power plants while drastically cutting carbon dioxide emissions, illuminating how the coal plant of the future could look.

01 COAL, LIGNITE, AND PEAT↗

Qinghai–tibetan plateau peatland sustainable utilization under anthropogenic disturbances and climate change

Often referred to as the “Third Pole,” China's Qinghai–Tibetan Plateau developed large amounts of peatland owing to its unique alpine environment. As a renewable resource, peat helps to regulate the climate as well as performing other important functions. However, in recent years, intensifying climate change and anthropogenic disturbances have resulted in peatland degradation and consequently made sustainable development of peatland more difficult. This review summarizes peatland ecological and economic functions, including carbon sequestration, biodiversity conservation, energy supplies, and ecotourism. It identifies climate change and anthropogenic disturbances as the two key factors attributing to peatland degradation and ecosystem carbon loss. Current problems in environmental degradation and future challenges in peatland management under the effects of global warming are also discussed and highlighted.

54 ENVIRONMENTAL SCIENCES↗

Utility maximizing dynamic resource management in an oversubscribed energy-constrained heterogeneous computing system

The need for greater performance in high performance computing systems combined with rising costs of electricity to power these systems motivates the need for energy-efficient resource management. Driven by the requirements of the Extreme Scale Systems Center at Oak Ridge National Laboratory, our study addresses the problem of scheduling dynamically-arriving tasks to machines in an oversubscribed and energy-constrained heterogeneous distributed computing environment. Our goal is to maximize total “utility” earned by the system, where the utility of a task is defined by a monotonically-decreasing function that represents the value of completing that task at different times. To address this problem, we design four energy-aware resource allocation heuristics and compare their performance to heuristics from the literature. For our given energy-constrained environment, we also design an energy filtering technique that helps some heuristics regulate their energy consumption by allowing tasks to only consume up to an estimated fair-share of energy. Extensive sensitivity analyses of the heuristics in environments with different levels of heterogeneity show that heuristics with the ability to balance both energy consumption and utility exhibit the best performance because they save energy for use by future tasks.

97 MATHEMATICS AND COMPUTING↗

Optimization of key energy and performance metrics for drug product manufacturing

During the development of pharmaceutical manufacturing processes, detailed systems-based analysis and optimization are required to control and regulate critical quality attributes within specific ranges, to maintain product performance. As discussions on carbon footprint, sustainability, and energy efficiency are gaining prominence, the development and utilization of these concepts in pharmaceutical manufacturing are seldom reported, which limits the potential of pharmaceutical industry in maximizing key energy and performance metrics. Based on an integrated modeling and techno-economic analysis framework previously developed by the authors, this study presents the development of a combined sensitivity analysis and optimization approach to minimize energy consumption while maintaining product quality and meeting operational constraints in a pharmaceutical process. The optimal input process conditions identified were validated against experiments and good agreement resulted between simulated and experimental data. Here, the results also allowed for a comparison of the capital and operational costs for batch and continuous manufacturing schemes under nominal and optimized conditions. Using the nominal batch operations as a basis, the optimized batch operation results in a 71.7% reduction of energy consumption, whereas the optimized continuous case results in an energy saving of 83.3%.

59 BASIC BIOLOGICAL SCIENCES↗

Predicting transcription factor activity using prior biological information

Dysregulation of normal transcription factor activity is a common driver of disease. Therefore, the detection of aberrant transcription factor activity is important to understand disease pathogenesis. We have developed Priori, a method to predict transcription factor activity from RNA sequencing data. Priori has two key advantages over existing methods. First, Priori utilizes literature-supported regulatory information to identify transcription factor-target gene relationships. It then applies linear models to determine the impact of transcription factor regulation on the expression of its target genes. Second, results from a third-party benchmarking pipeline reveals that Priori detects aberrant activity from 124 single-gene perturbation experiments with higher sensitivity and specificity than 11 other methods. We applied Priori and other top-performing methods to predict transcription factor activity from two large primary patient datasets. Our work demonstrates that Priori uniquely discovered significant determinants of survival in breast cancer and identified mediators of drug response in leukemia.

59 BASIC BIOLOGICAL SCIENCES↗

CP26 is not involved in qE- or qZ-type non-photochemical quenching in Arabidopsis

CP26 is a monomeric minor light-harvesting complex of Photosystem II (LHCII) protein located at the interface between LHCII trimers and the PSII core in thylakoid membranes. Previous studies have proposed that CP26 plays a role in non-photochemical quenching (NPQ) in addition to light harvesting. Here, we utilized biophysical and pharmacological approaches to investigate this role using single- and higher-order Arabidopsis (Arabidopsis thaliana) cp26 mutants, examining its relationship to known NPQ regulators (Photosystem II subunit S, PsbS, violaxanthin de-epoxidase, and the pH gradient across the thylakoid membrane). cp26 mutants showed significantly reduced maximum PSII quantum efficiencies (F v /F m ) in darkness, indicating a constitutively quenched state, further confirmed by fluorescence lifetime measurements. Destabilized PSII-LHCII supercomplexes observed in native gel electrophoresis and tighter PSII supercomplex packing were potential causes, with no other antenna proteins capable of rescuing this phenotype. In addition, the cp26 mutants exhibited altered NPQ capacity—modest in single mutants but substantial in double mutants—independent of PsbS and violaxanthin de-epoxidase. Together, these results show that CP26 is not involved in qE or qZ but may primarily play an indirect role in apparent NPQ responses via PSII-LHCII supercomplex organization.

Walter, Julia [University of Cambridge (United Kin↗

Bacteria “Read” Light To Gain a Competitive Advantage

Photosynthesis, the process of converting solar energy into stored chemical bonds, represents the primary mechanism by which biological organisms utilize photons. Light can also be used to activate a number of photosensory compounds and proteins designed to carry out tasks, such as DNA repair, gene regulation, and synchronization with the diurnal cycle. Given that sunlight is incident upon many environments, it is not farfetched to think that life may have evolved other as-yet-undetected mechanisms to profit from solar irradiation. In this issue, Maresca and coworkers detail their observations of light-enhanced growth of several nonphotosynthetic actinobacteria, as well as describe the potential photosensitizer responsible for this phenotype and discuss the regulatory networks involved (J. A. Maresca, J. L. Keffer, P. P. Hempel, S. W. Polson, et al., J Bacteriol 201:e00740-18, 2019,). This study opens the door to many intriguing questions about the use of light as information in nonphotosynthetic biological systems.

59 BASIC BIOLOGICAL SCIENCES↗