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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Caffeine Consumption Aboard the International Space Station

INTRODUCTION: Caffeine is the most widely used performance-enhancing drug on Earth and astronaut crews have access to liquid coffee. While caffeine is a potent countermeasure to improve alertness and performance, it can also interfere with sleep. This can lead to performance deficits on the following day, driving a cycle of caffeine use to counter the effects of caffeine-induced sleep disruption. Caffeine availability may be limited during future Artemis and/or Mars missions. Accordingly, it is important that we 1) determine the prevalence of caffeine use among astronauts, 2) characterize the impact of caffeine on performance, and 3) characterize the impact of caffeine on sleep. Our aim in this study is to describe the use of caffeine aboard the ISS and begin to examine the relationship between caffeine use and sleep and performance outcomes. METHODS: Daily caffeine consumption was determined from food and beverage intake tracking for 25 astronauts on 6 month International Space Station (ISS) missions. Data were recorded using the ISS Food Intake Tracker iPad App or other detailed recording technique. On average, crew recorded dietary intake on 179.7±68.6 (mean±SD) days inflight. RESULTS: Astronauts consumed 97±92 mg caffeine per day. All astronauts (25/25) in this study consumed caffeine at some point during flight, though the frequency, amounts, and regularity differed across crewmembers. Approximately a quarter of crewmembers were regular caffeine consumers (6/25), i.e., they ingested at least 90 mg caffeine (equivalent to one cup of coffee) on 90% of inflight days.

fatigue↗
NASA NTRSDate not supplied

Global Carbon Consumption Database for Wildland Fire

Fire significantly impacts both human-altered and wild landscapes on national and global scales. Though often devastating, wildland fires naturally reduce fuels, preventing larger wildfires. However, their smoke can harm human health locally and globally. To understand its impact on air quality and health, quantifying the emissions released into the atmosphere is crucial. To accurately model fire emissions, understanding fuel characteristics and burning conditions is crucial, as they vary with the fuelbed type and fire weather. For example, savanna fires have lower carbon loading and intensity but spread quickly, while boreal forest fires burn longer and release more carbon due to higher loading. Hotter, drier conditions increase fuel consumption and smoke plume height. Fire weather and available fuel are the key drivers of emissions.

Emily Gargulinski↗
DOE OSTI2014

System and method for controlling power consumption in a computer system based on user satisfaction

Systems and methods for controlling power consumption in a computer system. For each of a plurality of interactive applications, the method changes a frequency at which a processor of the computer system runs, receives an indication of user satisfaction, determines a relationship between the changed frequency and the user satisfaction of the interactive application, and stores the determined relationship information. The determined relationship can distinguish between different users and different interactive applications. A frequency may be selected from the discrete frequencies at which the processor of the computer system runs based on the determined relationship information for a particular user and a particular interactive application running on the processor of the computer system. The processor may be adapted to run at the selected frequency.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Hydrogen Production and Consumption in the U.S.: The Last 25 Years.

This article was requested by Cryogas International, which is celebrating its 25th anniversary this year. At the title suggests, the article identifies hydrogen consumption in the U.S., broken out by the major contributors to total production. Explanatory information is provided describing the causes underlying the significant changes seen in the summary data.

captive↗
DOE OSTI2017

Systems and methods to reduce reductant consumption in exhaust aftertreament systems

Systems, apparatus and methods are provided for reducing reductant consumption in an exhaust aftertreatment system that includes a first SCR device and a downstream second SCR device, a first reductant injector upstream of the first SCR device, and a second reductant injector between the first and second SCR devices. NOx conversion occurs with reductant injection by the first reductant injector to the first SCR device in a first temperature range and with reductant injection by the second reductant injector to the second SCR device when the temperature of the first SCR device is above a reductant oxidation conversion threshold.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Systems and methods to reduce reductant consumption in exhaust aftertreatment systems

Systems, apparatus and methods are provided for reducing reductant consumption in an exhaust after treatment system that includes a first SCR device and a downstream second SCR device, a first reductant injector upstream of the first SCR device, and a second reductant injector between the first and second SCR devices. NO x conversion occurs with reductant injection by the first reductant injector to the first SCR device in a first temperature range and with reductant injection by the second reductant injector to the second SCR device when the temperature of the first SCR device is above a reductant oxidation conversion threshold.

42 ENGINEERING↗
DOE OSTI2019

Impact of CAV Technologies on Energy Consumption of Advanced Electrified Vehicles

Transportation system simulation is a widely accepted approach to evaluate the impact of transport policy deployment. In developing a transportation system deployment model, the energy impact of the model is extremely valuable for sustainability and validation. It is expected that different penetration levels of Connected-Automated Vehicles (CAVs) will impact the travel behavior due to changes in potential factors such as congestion, miles traveled, etc. Along with such impact analyses, it is also important to further quantify the regional energy impact of CAV deployment under different factors of interest. The objective of this paper is to study the different penetration levels of CAVs deployment in the City of Chicago and how it impacts the energy consumption of electrified vehicles in the future. The paper will further provide a statistical analysis of the results to evaluate the impact of the different penetration levels on the different electrified powertrains used in the study.

Islam, Ehsan Sabri↗
DOE OSTI2018

Development of an Open-Source Life Cycle Baseline for Electricity Consumption in the U.S. - LCAXVIII

This work was presented at the American Center for Life Cycle Assessment (ACLCA) LCAXVIII Conference in Fort Collins, CO on September 25, 2018. EPA, NETL, and the National Renewable Energy Laboratory (NREL) collaborated to develop an open source multifunctional life cycle model to quantify baseline life cycle impacts of U.S. electricity consumption. This presentation discusses the steps that NETL is taking in development of Phase II of the electricity baseline. Specifically, NETL is expanding the spatiotemporal granularity to provide results at multiple levels of aggregation ranging from individual fossil facilities to the aggregated U.S. grid. Phase II will differentiate by individual technologies within fuel types as well as by function in the grid (baseload, cycling, load following, peaking). The supply chain inventory will be expanded with full access to the entire models.

Cooney, Greg↗
DOE OSTI2019

Assessing the Potential of Active Insulation Systems to Reduce Energy Consumption and Enhance Electrical Grid Services

Building envelopes today act as passive systems in a dynamic environment. Traditional energy-saving efforts have mainly tried to improve the performance of building envelope systems by increasing thermal resistance to a set value that reduces energy flow. However, changes in weather and indoor conditions often lead to situations in which a low thermal resistance would decrease energy use. The optimization of thermal resistance that is triggered by changes in temperature, solar radiation, or availability of energy from renewable sources is currently not possible. Controllable active insulation systems (AISs), in which the thermal resistance of the insulation material can be dynamically controlled within a certain range, can expand the capabilities of the building envelope. With AISs the building envelope is no longer only a passive barrier between indoors and outdoors; instead, heat transfer can be controlled. Moreover, when AISs are combined with the thermal mass in the envelope system, these can act as thermal batteries that can be loaded and unloaded on demand. To quantify the benefits of AISs, a literature study of active insulation and achievable thermal conductivity ranges, thermal simulation models, and control logics was performed. Based on this literature study, a simulation model was developed to control the thermal resistance of insulation materials. A methodology to assess the potential of active insulation systems to reduce energy use and enhance electrical grid services was established and applied to identify ideal implementation scenarios for active insulation systems. A significant reduction of total building energy consumption for heating and cooling was found in all climate zones. The savings for the slab-on-ground DOE residential prototype building for eight selected cities in different climate zones range from 4069 kBtu to 8433 kBtu. Depending on the control cooling during peak load hours in Los Angeles could be reduced by more than 80% without a negative impact on thermal comfort conditions.

Antretter, Florian↗
DOE OSTI2021

Transfer-Learnt Energy Models for Predicting Electricity Consumption in Buildings with Limited and Sparse Field Data

Modeling energy consumption is critical for energy-efficient utilization of the electric appliances in a building, smart grid programs (like demand-response), and many other smart home applications. State-of-the-art energy modeling techniques either rely on theoretical models, or extensive instrumentation of the building envelope to gather ``big" data to train a deep neural network. While theoretical models are often limited by their estimation accuracy, it is not always feasible to gather a significant amount of field data. In this paper, we explore transfer learning-based strategies to train much more accurate model for energy estimation when using a sparse field data. We transferred knowledge, in the form of data and parameters, from the simulation framework to the field data. We evaluated the efficacy of our approach on field data collected from six commercial buildings and our results indicate that transfer learning-based models trained over one month data can perform comparative (and in some cases better) than the state-of-the-art machine learning and deep learning solutions.

Jain, Milan↗
DOE OSTI2022

Gated ring oscillator with constant dynamic power consumption

A pure digital ring oscillator with constant power consumption as oscillation frequency is adjusted. Circuit topology includes a multiplexer implemented in NAND gates and a delay element positioned after a path selection NAND gate of that multiplexer such that delay element transistors may not toggle if the non-delaying signal path is selected. Assuming a delay element oscillation frequency f and a total capacitance C, and also assuming a plurality N of delay gates each characterized by a propagation delay t1 and a capacitance C1 such that C=C1*N, the ring oscillator of the present invention is characterized by a C value that is proportional to N and an f value that is inversely proportional to N. Furthermore, each of the N delay gates as well as the input and output gates of the multiplexer are characterized by a common capacitance-to-propagation delay ratio=C1/t1.

Wu, Jinyuan↗
DOE OSTI2023

Gated ring oscillator with constant dynamic power consumption

A pure digital ring oscillator with constant power consumption as oscillation frequency is adjusted. Circuit topology includes a multiplexer implemented in NAND gates and a delay element positioned after a path selection NAND gate of that multiplexer such that delay element transistors may not toggle if the non-delaying signal path is selected. Assuming a delay element oscillation frequency f and a total capacitance C, and also assuming a plurality N of delay gates each characterized by a propagation delay t1 and a capacitance C1 such that C=C1*N, the ring oscillator of the present invention is characterized by a C value that is proportional to N and an f value that is inversely proportional to N. Furthermore, each of the N delay gates as well as the input and output gates of the multiplexer are characterized by a common capacitance-to-propagation delay ratio=C1/t1.

Wu, Jinyuan↗
DOE OSTI2026

Energy Consumption, Performance, and Cost Estimates for Medium and Heavy-Duty Vehicles Based on 2022 Assumptions

Assumptions for this work was collected and the analysis was completed in FY22. This contains information for more than 20 types of medium and heavy duty vehicles. Vehicles with various levels of hybridization, electric and fuel cell powertrains are considered in this work. More details are available in the report published by Argonne accessible from https://vms.taps.anl.gov/research-highlights/u-s-doe-vto-hfto-r-d-benefits/. TechScape, a convenient data visualization tool is also provided by Argonne for this data, accessible from [TechScape Web](https://vms.taps.anl.gov/data/techscape-web-2023/).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Chapter 8: Whole-Building Retrofit with Consumption Data Analysis Evaluation Protocol. The Uniform Methods Project: Methods for Determining Energy Efficiency Savings for Specific Measures

Whole-building retrofits involve the installation of multiple measures. Whole-building retrofit programs take many forms. With a focus on overall building performance, these programs usually begin with an energy audit to identify cost-effective energy efficiency measures for the home. Measures are then installed, either at no cost to the homeowner or partially paid for by rebates and/or financing. The methods described here may also be applied to evaluation of single-measure retrofit programs. Related methods exist for replace-on-failure programs and for new construction, but are not the subject of this chapter.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2017

Pittsburgh 2013 Energy Baseline: Consumption, Trends & Opportunities

The United States (U.S.) Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) are working in conjunction with the City of Pittsburgh (City) to transform how energy is produced, transported, and consumed in the City. This transformation will rely on 21st Century Energy Infrastructure designs, which leverage advanced technology and design techniques to modernize energy infrastructure, create new business models and markets, and expand technology research and development opportunities. Achieving this vision will require developing solutions that are unique to the City: its climate, topography, energy needs, resources, and existing infrastructure.a In this way, the City will demonstrate what the American “City of the Future” looks like, with all its attendant environmental, economic, and job-creation benefits. It will also serve as a template for other cities seeking to reinvent their energy systems.

02 PETROLEUM↗