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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Fundamentals of Thermal Expansion and Thermal Contraction

Thermal expansion is an important property of substances. Its theoretical prediction has been challenging, particularly in cases the volume decreases with temperature, i.e., thermal contraction or negative thermal expansion at high temperatures. In this paper, a new theory recently developed by the authors has been reviewed and further examined in the framework of fundamental thermodynamics and statistical mechanics. Its applications to cerium with colossal thermal expansion and Fe 3 Pt with thermal contraction in certain temperature ranges are discussed. It is anticipated that this theory is not limited to volume only and can be used to predict a wide range of properties at finite temperatures.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Energy Savings Performance Contracts (ESPC): FEMP Assistance

An ESPC is a working relationship between a Federal agency and an energy service company (ESCO). The ESCO conducts a comprehensive energy audit for the Federal facility and identifies improvements to save energy. In consultation with the Federal agency, the ESCO designs and constructs a project that meets the agency’s needs and arranges the necessary funding. The ESCO guarantees the improvements will generate energy cost savings sufficient to pay for the project over the term of the contract. After the contract ends, all additional cost savings accrue to the agency.

Energy, Savings, Contracts, ESPC, FEMP, Assistance↗
DOE OSTI2013

Utility Energy Services Contracts Guide

The UESC Guide is a compilation of samples and templates developed as a resource to help contracting officers implement task orders for UESCs under existing U.S. General Services Administration areawide contracts.

FEMP↗
DOE OSTI2017

Energy Savings Performance Contract Energy Sales Agreement Toolkit

FEMP developed the Energy Savings Performance Contracting Energy Sales Agreement (ESPC ESA) Toolkit to provide federal agency contracting officers and other acquisition team members with information that will facilitate the timely execution of ESPC ESA projects.

energy sales agreements↗
DOE OSTI2019

Performance Assurance Planning: Continuous Design-Level Performance of Each Energy Conservation Measure in a Utility Energy Service Contract is Fundamental to Achieving Projected Results

Design-level performance of each energy conservation measure (ECM) in an awarded utility energy service contract (UESC) is fundamental to achieving the projected results through the term of the contract and over the life of the measure. Because the authority for a UESC does not require contractual guarantees of energy, water, or cost savings, FEMP developed a protocol for emphasizing sustained performance to help ensure projected savings are realized. The information and templates offered within this paper reflect responsible project management and oversight, align with UESC best practices, and satisfy the conditions for annual scoring provided by the Office of Management and Budget (OMB). OMB memorandum M-12-21 requires, 'energy savings performance assurances,' 'measurement and verification (M&V) of savings through commissioning and retrocommissioing,' and 'competition or an alternatives analysis as part of the selection process.'

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2022

Standardization of Smart Contracts for Energy Markets and Operation

This work presents a formal review of smart contracts, including definitions, technical requirements, and potential power and energy-related use cases. This includes in-depth discussions covering cybersecurity, legality and interoperability goals that must be taken into consideration by potential end-users. The paper presents a first attempt towards the standardization of smart contracts (SCs) within the field of power and energy as a work in progress activity under the IEEE Standards Association (IEEE SA) P2418.5 Working Group. This work also proposes a holistic, language-agnostic reference model that is intended to accelerate the adoption of Distributed Ledger Technology (DLT) by industry stakeholders by providing standardized processes. Finally, the paper discusses key takeaways that must continue to be developed to increase SC usage within the energy industry.

Blockchain, smart contracts, DLT↗
DOE OSTI2013

Maximizing Operational Efficiencies in Waste Management on the Hanford Plateau Remediation Contract in a Down-turned Market - 13484

Recent changes in DOE priorities and funding have pressed DOE and its contractors to look for innovative methods to sustain critical operations at sites across the Complex. At the Hanford Site, DOE Richland Operations and its prime contractor, CH2M Hill Plateau Remediation Company (CHPRC), have completed in-depth assessments of the Plateau Remediation Contract (PRC) operations that compared available funding to mission and operational objectives in an effort to maintain requisite safety and compliance margins while realizing cost savings that meet funding profiles. These assessments included confirmation of current baseline activities, identification of potential efficiencies, barriers to implementation, and potential increased risks associated with implementation. Six operating PRC waste management facilities were evaluated against three possible end-states: complete facility closure, maintaining base operations, and performing minimum safe surveillance and maintenance activities. The costs to completely close evaluated facilities were determined to be prohibitively high and this end-state was quickly dropped from consideration. A summary of the analysis of remaining options by facility, efficiencies identified, impact to risk profiles, and expected cost savings is provided in Table I. The expected cost savings are a result of: - right-sizing and cross-training work crews to address maintenance activities across facilities; - combining and sequencing 'like-moded' operational processes; - cross-cutting emergency planning and preparedness staffing; - resource redistribution and optimization; - reducing areas requiring routine surveillance and inspection. For the efficiencies identified, there are corresponding increases in risk, including a loss of breadth and depth of available resources; lengthened response time to emergent issues; inability to invest in opportunities for improvement (OFIs); potential single-point failures or non-compliancies due to resource scarcity; limited cross-training capability; and reduced capability to respond to changes in DOE priorities. Finally, there are many challenges to achieving these cost savings. With a workforce nearing retirement effective succession planning becomes critical to success and requires establishing a balance between the cost of hiring and training and cost-saving activities. With six active waste management facilities spread across nearly 15 square miles, scheduling and deploying cross-trained surveillance and maintenance teams is a logistical challenge, particularly as the loss of funding has not diminished emphasis by regulatory agencies placed on the safe and compliant performance of DOE and its contractors. As reflected in Table I, efficiencies are currently being implemented on the Hanford Plateau Remediation Contract (PRC) that deliver cost savings that align with the current site budget while maintaining critical capabilities. It is currently estimated that these efficiencies will result in a cost savings of approximately $9 million for FY13 in base and minimum safe operations on the PRC - a cost reduction of more than 13 percent over FY12 and nearly 30 percent over FY09 levels. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

The sodium channel Na X : Possible player in excitation–contraction coupling

Abstract The sodium channel Na X (encoded by the SCN7A gene) was originally identified in the heart and skeletal muscle and is structurally similar to the other voltage‐gated sodium channels but does not appear to be voltage gated. Although Na X is expressed at high levels in cardiac and skeletal muscle, little information exists on the function of Na X in these tissues. Transcriptional profiling of ion channels in the heart in a subset of patients with Brugada syndrome revealed an inverse relationship between the expression of Na X and Na V 1.5 suggesting that, in cardiac myocytes, the expression of these channels may be linked. We propose that Na X plays a role in excitation–contraction coupling based on our experimental observations. Here we show that in cardiac myocytes, Na X is expressed in a striated pattern on the sarcolemma in regions corresponding to the sarcomeric M‐line. Knocking down Na X expression decreased Na V 1.5 mRNA and protein and reduced the inward sodium current ( I Na+ ) following cell depolarization. When the expression of Na V 1.5 was knocked down, ~85% of the I Na+ was reduced consistent with the observations that Na V 1.5 is the main voltage‐gated sodium channel in cardiac muscle and that Na X likely does not directly participate in mediating the I Na+ following depolarization. Silencing Na V 1.5 expression led to significant upregulation of Na X mRNA. Similar to Na V 1.5, Na X protein levels were rapidly downregulated when the intracellular [Ca 2+ ] was increased either by CaCl 2 or caffeine. These data suggest that a relationship exists between Na X and Na V 1.5 and that Na X may play a role in excitation–contraction coupling.

Bogdanovic, Elena↗
DOE OSTI2024

Properties of the contraction map for holographic entanglement entropy inequalities

We present a deterministic way of finding contraction maps for candidate holographic entanglement entropy inequalities modulo choices due to actual degeneracy. We characterize its complexity and give an argument for the completeness of the contraction map proof method as a necessary and sufficient condition for the validity of an entropy inequality for holographic entanglement.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2010

Spatial contraction of the Poincare group and Maxwell's equations in the electric limit

The contraction of the Poincare group with respect to the space translations subgroup gives rise to a group that bears a certain duality relation to the Galilei group, that is, the contraction limit of the Poincare group with respect to the time translations subgroup. In view of this duality, we call the former the dual Galilei group. A rather remarkable feature of the dual Galilei group is that the time translations constitute a central subgroup. Therewith, in unitary irreducible representations (UIRs) of the group, the Hamiltonian appears as a Casimir operator proportional to the identity H = EI, with E (and a spin value s) uniquely characterizing the representation. Hence, a physical system characterized by a UIR of the dual Galilei group displays no non-trivial time evolution. Moreover, the combined U(1) gauge group and the dual Galilei group underlie a non-relativistic limit of Maxwell's equations known as the electric limit. The analysis presented here shows that only electrostatics is possible for the electric limit, wholly in harmony with the trivial nature of time evolution governed by the dual Galilei group.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2026

Sculpting 2D Crystals via Membrane Contractions before and during Solidification

When phospholipids crystallize within the otherwise fluid membranes of giant unilamellar vesicles, the resulting molecularly thin “2D” solids exhibit great variety in their morphology evolution. For example, within membranes containing moderate amounts of the crystallizing component, crystals grow with a fixed morphology depending on vesicle size. Conversely for membranes containing large amounts of the crystallizing species, we find small compact crystals on vesicles of all sizes. However, on large vesicles, growing crystals sprout flower petals that lengthen progressively. These behaviors result from two combined mechanisms: first, like other 2D solids, the shear rigidity of phospholipid crystals renders them intolerant to morphologies with nonzero Gaussian curvature. As a result and especially at elevated membrane tension, the cost of bending elasticity is reduced at the expense of line energy by the formation of flowers as opposed to compact crystals. Second, the composition-dependent tension rise during cooling relaxes via water permeation of the membrane with a time constant scaling as R2. The amount of crystal formed for a small decrease in temperature determines this composition-dependent increase in stress from thermal contractions versus solidification. Surface Evolver computations were motivated using the predicted tension evolution to develop a processing space that maps to experimental observations for initial and growing crystal morphology. Important variable groups are identified, including a scaled ratio of bending to line energy, a vesicle-size-independent group for membrane contractions, and a time constant for stress relaxation. Though processing stresses ultimately relax, the crystal morphology persists well beyond the processing window.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Band Gap Tuning via Lattice Contraction and Octahedral Tilting in Perovskite Materials for Photovoltaics

Tin and lead iodide perovskite semiconductors of the composition AMX 3 , where M is a metal and X is a halide, are leading candidates for high efficiency low cost tandem photovoltaics, in part because they have band gaps that can be tuned over a wide range by compositional substitution. We experimentally identify two competing mechanisms through which the A-site cation influences the band gap of 3D metal halide perovskites. Using a smaller A-site cation can distort the perovskite lattice in two distinct ways: by tilting the MX 6 octahedra or by simply contracting the lattice isotropically. The former effect tends to raise the band gap, while the latter tends to decrease it. Lead iodide perovskites show an increase in band gap upon partial substitution of the larger formamidinium with the smaller cesium, due to octahedral tilting. Perovskites based on tin, which is slightly smaller than lead, show the opposite trend: they show no octahedral tilting upon Cs-substitution but only a contraction of the lattice, leading to progressive reduction of the band gap. We outline a strategy to systematically tune the band gap and valence and conduction band positions of metal halide perovskites through control of the cation composition. Using this strategy, we demonstrate solar cells that harvest light in the infrared up to 1040 nm, reaching a stabilized power conversion efficiency of 17.8%, showing promise for improvements of the bottom cell of all-perovskite tandem solar cells. In conclusion, the mechanisms of cation-based band gap tuning we describe are broadly applicable to 3D metal halide perovskites and will be useful in further development of perovskite semiconductors for optoelectronic applications.

14 SOLAR ENERGY↗
DOE OSTI2017

Colossal Volume Contraction in Strong Polar Perovskites of Pb(Ti,V)O 3

The unique physical property of negative thermal expansion (NTE) is not only interesting for scientific research but also important for practical applications. Chemical modification generally tends to weaken NTE. It remains a challenge to obtain enhanced NTE from currently available materials. Herein, we successfully achieve enhanced NTE in Pb(Ti 1-x V x )O 3 by improving its ferroelectricity. With the chemical substitution of vanadium, lattice tetragonality (c/a) is highly promoted, which is attributed to strong spontaneous polarization, evidenced by the enhanced covalent interaction in the V/Ti-O and Pb-O2 bonds from first principles calculations. As a consequence, Pb(Ti 0.9 V 0.1 )O 3 exhibits a nonlinear and much stronger NTE over a wide temperature range with a volumetric coefficient of thermal expansion α v = -3.76 X 10 -5 /ºC (25-550 ºC). Interestingly, an intrinsic giant volume contraction (~3.7%) was obtained at the composition of Pb(Ti 0.7 V 0.3 )O 3 during the ferroelectric-to-paraelectric phase transition, which represents the highest value ever reported. Such volume contraction is well correlated to the effect of spontaneous volume ferroelectrostriction. This study extends the scope of the NTE family and provides an effective approach to explore new materials with large NTE, such as through adjusting the NTE-related ferroelectric property in the family of ferroelectrics.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Using Financial Contracts to Facilitate Informal Leases Within a Western United States Water Market Based on Prior Appropriation

The ability to reallocate water to higher-value uses during drought is an increasingly important “soft-path” tool for managing water resources in an uncertain future. In most of the Western United States, state-level water market institutions that enable reallocation also impose substantial transaction costs on market participants related to regulatory approval and litigation. These transaction costs can be prohibitive for many participants in terms of both costs and lengthy approval periods, limiting transfers and reducing allocation efficiency, particularly during drought crises periods. This manuscript describes a mechanism to reduce transaction costs by adapting an existing form of informal leases to facilitate quicker and less expensive transfers among market participants. Instead of navigating the formal approval process to lease a water right, informal leases are financial contracts for conservation that enable more junior holders of existing rights to divert water during drought, thereby allowing the formal transfer approval process to be bypassed. The informal leasing approach is tested in the Upper Colorado River Basin, where drought and institutional barriers to transfers lead to frequent shortages for urban rights holders along Colorado's Front Range. Informal leases are facilitated via option contracts that include adaptive triggers and that define volumes of additional, compensatory, releases designed to mitigate impacts to instream flows and third parties. Results suggest that more rapid reallocation of water via informal leases could have resulted in up to $222 million in additional benefits for urban rights holders during the historical period 1950–2013.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2017

Simultaneous electrical recording of cardiac electrophysiology and contraction on chip

Prevailing commercialized cardiac platforms for in vitro drug development utilize planar microelectrode arrays to map action potentials, or impedance sensing to record contraction in real time, but cannot record both functions on the same chip with high spatial resolution. We report a novel cardiac platform that can record cardiac tissue adhesion, electrophysiology, and contractility on the same chip. The platform integrates two independent yet interpenetrating sensor arrays: a microelectrode array for field potential readouts and an interdigitated electrode array for impedance readouts. Together, these arrays provide real-time, non-invasive data acquisition of both cardiac electrophysiology and contractility under physiological conditions and under drug stimuli. Furthermore, we cultured human induced pluripotent stem cell-derived cardiomyocytes as a model system, and used to validate the platform with an excitation–contraction decoupling chemical. Preliminary data using the platform to investigate the effect of the drug norepinephrine are combined with computational efforts. Finally, this platform provides a quantitative and predictive assay system that can potentially be used for comprehensive assessment of cardiac toxicity earlier in the drug discovery process.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Contraction of polymer gels created by the activity of molecular motors

Here, we propose a theory based on non-equilibrium thermodynamics to describe the mechanical behavior of an active polymer gel created by the inclusion of molecular motors in its solvent. When activated, these motors attach to the chains of the polymer network and shorten them creating a global contraction of the gel, which mimics the active behavior of a cytoskeleton. The power generated by these motors is obtained by an ATP hydrolysis reaction, which transduces chemical energy into mechanical work. The latter is described by an increment of strain energy in the gel due to an increased stiffness. This effect is described with an increment of the cross-link density in the polymer network, which reduces its entropy. The theory then considers polymer network swelling and species diffusion to describe the transient passive behavior of the gel. We finally formulate the problem of uniaxial contraction of a slab of gel and compare the results with experiments, showing good agreement.

36 MATERIALS SCIENCE↗