The use of hydrogen for aircraft propulsion in view of the fuel crisis

NASA Technical Reports Server (NTRS)

Weiss, S.

1973-01-01

Some factors influencing the technical feasibility of operating a liquid hydrogen-fueled airplane are discussed in light of the projected decrease of fossil fuels. Other sources of energy, such as wind, tidal, solar, and geothermal, are briefly mentioned. In view of projected decreases in available petroleum fuels, interest has been generated in exploiting the potential of liquid hydrogen (LH2) as an aircraft fuel. Cost studies of LH2 production show it to be more expensive than presently used fuels. Regardless of cost considerations, LH2 is viewed as an attractive aircraft fuel because of the potential performance benefits it offers. Accompanying these benefits, however, are many new problems associated with aircraft design and operations; for example, problems related to fuel system design and the handling of LH2 during ground servicing. Some of the factors influencing LH2 fuel tank design, pumping, heat exchange, and flow regulation are discussed.

Kerosene: a review of household uses and their hazards in low- and middle-income countries.

PubMed

Lam, Nicholas L; Smith, Kirk R; Gauthier, Alison; Bates, Michael N

2012-01-01

Kerosene has been an important household fuel since the mid-19th century. In developed countries its use has greatly declined because of electrification. However, in developing countries, kerosene use for cooking and lighting remains widespread. This review focuses on household kerosene uses, mainly in developing countries, their associated emissions, and their hazards. Kerosene is often advocated as a cleaner alternative to solid fuels, biomass and coal, for cooking, and kerosene lamps are frequently used when electricity is unavailable. Globally, an estimated 500 million households still use fuels, particularly kerosene, for lighting. However, there are few studies, study designs and quality are varied, and results are inconsistent. Well-documented kerosene hazards are poisonings, fires, and explosions. Less investigated are exposures to and risks from kerosene's combustion products. Some kerosene-using devices emit substantial amounts of fine particulates, carbon monoxide (CO), nitric oxides (NO(x)), and sulfur dioxide (SO(2)). Studies of kerosene used for cooking or lighting provide some evidence that emissions may impair lung function and increase infectious illness (including tuberculosis), asthma, and cancer risks. However, there are few study designs, quality is varied, and results are inconsistent. Considering the widespread use in the developing world of kerosene, the scarcity of adequate epidemiologic investigations, the potential for harm, and the implications for national energy policies, researchers are strongly encouraged to consider collecting data on household kerosene uses in studies of health in developing countries. Given the potential risks of kerosene, policymakers may consider alternatives to kerosene subsidies, such as shifting support to cleaner technologies for lighting and cooking.

KEROSENE: A REVIEW OF HOUSEHOLD USES AND THEIR HAZARDS IN LOW- AND MIDDLE-INCOME COUNTRIES

PubMed Central

Lam, Nicholas L.; Smith, Kirk R.; Gauthier, Alison; Bates, Michael N.

2013-01-01

Kerosene has been an important household fuel since the mid-19th century. In developed countries its use has greatly declined because of electrification. However, in developing countries, kerosene use for cooking and lighting remains widespread. This review focuses on household kerosene uses, mainly in developing countries, their associated emissions, and their hazards. Kerosene is often advocated as a cleaner alternative to solid fuels, biomass and coal, for cooking, and kerosene lamps are frequently used when electricity is unavailable. Globally, an estimated 500 million households still use fuels, particularly kerosene, for lighting. However, there are few studies, study designs and quality are varied, and results are inconsistent. Well-documented kerosene hazards are poisonings, fires, and explosions. Less investigated are exposures to and risks from kerosene’s combustion products. Some kerosene-using devices emit substantial amounts of fine particulates, carbon monoxide (CO), nitric oxides (NOx), and sulfur dioxide (SO2). Studies of kerosene used for cooking or lighting provide some evidence that emissions may impair lung function and increase infectious illness (including tuberculosis), asthma, and cancer risks. However, there are few study designs, quality is varied, and results are inconsistent. Considering the widespread use in the developing world of kerosene, the scarcity of adequate epidemiologic investigations, the potential for harm, and the implications for national energy policies, researchers are strongly encouraged to consider collecting data on household kerosene uses in studies of health in developing countries. Given the potential risks of kerosene, policymakers may consider alternatives to kerosene subsidies, such as shifting support to cleaner technologies for lighting and cooking. PMID:22934567

Comparative analysis of LWR and FBR spent fuels for nuclear forensics evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Permana, Sidik; Suzuki, Mitsutoshi; Su'ud, Zaki

2012-06-06

Some interesting issues are attributed to nuclide compositions of spent fuels from thermal reactors as well as fast reactors such as a potential to reuse as recycled fuel, and a possible capability to be manage as a fuel for destructive devices. In addition, analysis on nuclear forensics which is related to spent fuel compositions becomes one of the interesting topics to evaluate the origin and the composition of spent fuels from the spent fuel foot-prints. Spent fuel compositions of different fuel types give some typical spent fuel foot prints and can be estimated the origin of source of those spentmore » fuel compositions. Some technics or methods have been developing based on some science and technological capability including experimental and modeling or theoretical aspects of analyses. Some foot-print of nuclear forensics will identify the typical information of spent fuel compositions such as enrichment information, burnup or irradiation time, reactor types as well as the cooling time which is related to the age of spent fuels. This paper intends to evaluate the typical spent fuel compositions of light water (LWR) and fast breeder reactors (FBR) from the view point of some foot prints of nuclear forensics. An established depletion code of ORIGEN is adopted to analyze LWR spent fuel (SF) for several burnup constants and decay times. For analyzing some spent fuel compositions of FBR, some coupling codes such as SLAROM code, JOINT and CITATION codes including JFS-3-J-3.2R as nuclear data library have been adopted. Enriched U-235 fuel composition of oxide type is used for fresh fuel of LWR and a mixed oxide fuel (MOX) for FBR fresh fuel. Those MOX fuels of FBR come from the spent fuels of LWR. Some typical spent fuels from both LWR and FBR will be compared to distinguish some typical foot-prints of SF based on nuclear forensic analysis.« less

Demonstration of fuel switching on oceangoing vessels in the Gulf of Mexico.

PubMed

Browning, Louis; Hartley, Seth; Bandemehr, Angela; Gathright, Kenneth; Miller, Wayne

2012-09-01

Switching fuels from high-sulfur heavy fuel oils (HFO) to lower sulfur marine gas oils (MGO) on an oceangoing vessel (OGV) can substantially reduce both PM and SO(x) ship stack emissions, potentially resulting in significant human health and environmental benefits in Gulf of Mexico port communities. The International Maritime Organization (IMO) established an emission control area (ECA) within 200 nautical miles of the US. and Canadian coastlines and French territories off the coast of Canada with lower fuel sulfur standards effective beginning August 2012, where OGVs will need to switch from HFO to MGO. However some operators and other stakeholders, particularly in the Gulf of Mexico, may be unfamiliar with the benefits and requirements and ship operators may be concerned over potential implications for cost and operations. This first-ever US. Environmental Protection Agency (EPA)-sponsored fuel switching demonstration in the Gulf of Mexico was initiated to showcase the environmental and health benefits of as well as operational issues associated with, fuel switching through the following activities: (1) Fuel switching was conducted on typical container ships operating the Gulf of Mexico, as routine fuel switching has been demonstrated in California in recent years. Two vessels were employed in the demonstration: the Maersk Roubaix, which switched fuels entering Port of Houston, TX, and the Port of Progreso, Mexico, and the Hamburg Süd vessel Cap San Lorenzo, which switched fuels entering the Port of Houston and the Mexican Ports of Veracruz and Altamira. Operational and cost aspects were also noted. (2) Emissions reductions were quantified through both a calculation approach based on fuel use of the Maersk Line vessel Roubaix and in-stack monitoring of emissions from the Hamburg Süd Cap San Lorenzo. Pollutant emissions including PM, SO(x), NO(x), and PM component speciation were sampled during use of both fuels. These observations showed reductions (1-6%) in NO(x) and substantial reductions in PM (50-70%) and SO(x) (> 99%) depending on engine and load. (3) Emission inventories at three ports were calculated. (4) Potential health and environmental benefits to communities and ecosystems in the Gulf of Mexico were estimated through screening-level modeling of air dispersion and atmospheric deposition of ship emissions at the Port of Veracruz to indicate the substantial reductions available through fuel switching. The United States and Canada have recently adopted a North American Emission Control Area that will require a shift from high-sulfur to low-sulfur fuels in the marine transportation sector. Cleaner fuels are expected to reduce sulfur and particulate emissions. This paper verifies the feasibility of such switching operations, the potential to reduce emissions if extended to the Gulf of Mexico, and the associated environmental impacts of these emission reductions inland and to sensitive ecosystems.

Targeting fundamental pathways to disrupt Staphylococcus aureus survival: clinical implications of recent discoveries

PubMed Central

Thomsen, Isaac P.; Liu, George Y.

2018-01-01

The emergence of community-associated methicillin-resistant Staphylococcus aureus during the past decade along with an impending shortage of effective antistaphylococcal antibiotics have fueled impressive advances in our understanding of how S. aureus overcomes the host environment to establish infection. Backed by recent technologic advances, studies have uncovered elaborate metabolic, nutritional, and virulence strategies deployed by S. aureus to survive the restrictive and hostile environment imposed by the host, leading to a plethora of promising antimicrobial approaches that have potential to remedy the antibiotic resistance crisis. In this Review, we highlight some of the critical and recently elucidated bacterial strategies that are potentially amenable to intervention, discuss their relevance to human diseases, and address the translational challenges posed by current animal models. PMID:29515041

Developing Custom Fire Behavior Fuel Models for Mediterranean Wildland-Urban Interfaces in Southern Italy

NASA Astrophysics Data System (ADS)

Elia, Mario; Lafortezza, Raffaele; Lovreglio, Raffaella; Sanesi, Giovanni

2015-09-01

The dramatic increase of fire hazard in wildland-urban interfaces (WUIs) has required more detailed fuel management programs to preserve ecosystem functions and human settlements. Designing effective fuel treatment strategies allows to achieve goals such as resilient landscapes, fire-adapted communities, and ecosystem response. Therefore, obtaining background information on forest fuel parameters and fuel accumulation patterns has become an important first step in planning fuel management interventions. Site-specific fuel inventory data enhance the accuracy of fuel management planning and help forest managers in fuel management decision-making. We have customized four fuel models for WUIs in southern Italy, starting from forest classes of land-cover use and adopting a hierarchical clustering approach. Furthermore, we provide a prediction of the potential fire behavior of our customized fuel models using FlamMap 5 under different weather conditions. The results suggest that fuel model IIIP (Mediterranean maquis) has the most severe fire potential for the 95th percentile weather conditions and the least severe potential fire behavior for the 85th percentile weather conditions. This study shows that it is possible to create customized fuel models directly from fuel inventory data. This achievement has broad implications for land managers, particularly forest managers of the Mediterranean landscape, an ecosystem that is susceptible not only to wildfires but also to the increasing human population and man-made infrastructures.

Developing Custom Fire Behavior Fuel Models for Mediterranean Wildland-Urban Interfaces in Southern Italy.

PubMed

Elia, Mario; Lafortezza, Raffaele; Lovreglio, Raffaella; Sanesi, Giovanni

2015-09-01

The dramatic increase of fire hazard in wildland-urban interfaces (WUIs) has required more detailed fuel management programs to preserve ecosystem functions and human settlements. Designing effective fuel treatment strategies allows to achieve goals such as resilient landscapes, fire-adapted communities, and ecosystem response. Therefore, obtaining background information on forest fuel parameters and fuel accumulation patterns has become an important first step in planning fuel management interventions. Site-specific fuel inventory data enhance the accuracy of fuel management planning and help forest managers in fuel management decision-making. We have customized four fuel models for WUIs in southern Italy, starting from forest classes of land-cover use and adopting a hierarchical clustering approach. Furthermore, we provide a prediction of the potential fire behavior of our customized fuel models using FlamMap 5 under different weather conditions. The results suggest that fuel model IIIP (Mediterranean maquis) has the most severe fire potential for the 95th percentile weather conditions and the least severe potential fire behavior for the 85th percentile weather conditions. This study shows that it is possible to create customized fuel models directly from fuel inventory data. This achievement has broad implications for land managers, particularly forest managers of the Mediterranean landscape, an ecosystem that is susceptible not only to wildfires but also to the increasing human population and man-made infrastructures.

A Consumer-Oriented Control Framework for Performance Analysis in Hybrid Electric Vehicles

DOE PAGES

Shaltout, Mohamed L.; Malikopoulos, Andreas A.; Pannala, Sreekanth; ...

2014-12-09

Hybrid electric vehicles (HEVs) have attracted considerable attention due to their potential to reduce fuel consumption and emissions. Our objective with this paper is to enhance our understanding of the associated tradeoffs among the HEV subsystems, e.g., the engine, the motor, and the battery, and investigate the related implications for fuel consumption and battery capacity and lifetime. Addressing this problem can provide insights on how to prioritize these objectives based on consumers needs and preferences. The results of the proposed optimization approach can also be used to investigate the implications for HEV costs related to ownership and warranty.

Radiotoxicity Characterization of Multi-Recycled Thorium Fuel - 12394

DOE Office of Scientific and Technical Information (OSTI.GOV)

Franceschini, F.; Wenner, M.; Fiorina, C.

2012-07-01

As described in companion papers, Westinghouse is proposing the implementation of a thorium based fuel cycle to burn the transuranic (TRU) contained in the used nuclear fuel. The potential of thorium as a TRU burner is described in another paper presented at this conference. This paper analyzes the long-term impact of thorium on the front-end and backend of the fuel cycle. This is accomplished by an assessment of the isotopic make-up of Th in a closed cycle and its impact on representative metrics, such as radiotoxicity, decay heat and gamma heat. The behavior in both thermal and fast neutron energymore » ranges has been investigated. Irradiation in a Th fuel PWR has been assumed as representative of the thermal range, while a Th fuel fast reactor (FR) has been employed to characterize the behavior in the high-energy range. A comparison with a U-fuel closed-cycle FR has been undertaken in an attempt of a more comprehensive evaluation of each cycle's long-term potential. As the Th fuel undergoes multiple cycles of irradiation, the isotopic composition of the recycled fuel changes. Minor Th isotopes are produced; U-232 and Pa-231 build up; the U vector gradually shifts towards increasing amounts of U-234, U-235 etc., eventually leading to the production of non negligible amounts of TRU isotopes, especially Pu-238. The impact of the recycled fuel isotopic makeup on the in-core behavior is mild, and for some aspects beneficial, i.e. the reactivity swing during irradiation is reduced as the fertile characteristics of the fuel increase. On the other hand, the front and the back-end of the fuel cycle are negatively affected due to the presence of Th-228 and U-232 and the build-up of higher actinides (Pu-238 etc.). The presence of U-232 can also be seen as advantageous as it represents an obstacle to potential proliferators. Notwithstanding the increase in the short-term radiotoxicity and decay heat in the multi-recycled fuel, the Th closed cycle has some potentially substantial advantages compared to the U cycle, such as the smaller actinide radiotoxicity and decay heat for up to 25,000 years after irradiation. In order for these benefits to materialize, the capability to reprocess and remotely manufacture industrial amounts of recycled fuel appears to be the key. Westinghouse is proposing the implementation of a thorium based fuel cycle to burn the TRU contained in the current UNF. The general approach and the potential of thorium as TRU burner is described in other papers presented at this conference. The focus of this paper is to analyze the long-term potential of thorium, once the legacy TRU has been exhausted and the thorium reactor system will become self-sufficient. Therefore, a comparison of Th closed cycle, in fast and thermal neutron energy ranges, vs. U closed cycle, in the fast energy range, has been undertaken. The results presented focus on selected backend and front-end metrics: isotopic actinide composition and potential implications on ingested radiotoxicity, decay heat and gamma heat. The evaluation confirms potential substantial improvements in the backend of the fuel cycle by transitioning to a thorium closed cycle. These benefits are the result of a much lower TRU content, in particular Pu-241, Am-241 and Pu-240, characterizing the Th vs. U actinide inventories, and the ensuing process waste to be disposed. On the other hand, the larger gamma activity of Th recycled fuel, consisting predominantly of hard gammas from U-232's decay products, is a significant challenge for fuel handling, transportation and manufacturing but can be claimed as beneficial for the proliferation resistance of the fuel. It is worth remembering that in our perspective the Th closed cycle and the U closed cycle will follow a transmutation phase which will likely take place over several decades and dictate the technologies required. These will likely include remote fuel manufacturing, regardless of the specific system adopted for the transmutation, which could then be inherited for the ensuing closed cycles. Finally, specific data related to the fuel manufacturing and separation technologies and their performance in the prospected industrial scale deployment, are key for further quantification of the potential merits of the options explored. Further studies in this direction should be warranted before making definitive conclusion. (authors)« less

3D Stagnation instabilities in MagLIF loads on the Z Generator

NASA Astrophysics Data System (ADS)

Jennings, Christopher

2017-10-01

Experiments with Magnetized Liner Inertial Fusion (MagLIF) loads have successfully demonstrated the premise of magnetized fusion. While these experiments are increasingly well diagnosed, many of the measurements (particularly during stagnation) are time integrated, limited in spatial resolution or require additional assumptions to interpret in the context of a structured, rapidly evolving system. As such, there is some ambiguity over what may be limiting performance. Poor laser coupling in preheating the fuel prior to implosion has been suggested as a mechanism. Mix of high Z contaminants that cool the fuel is also a significant concern. In addition, time integrated crystal imaging has shown significant structure in the final fuel assembly indicating potential disruption from instabilities. Understanding the balance between these degradation mechanisms is vital to progress with MagLif. We compare several sets of experimental data with synthetically generated data from systematically varied 3D resistive-MHD simulations to gain insight into the relative contributions of different degradation mechanisms. We demonstrate how some measurements strongly indicate disruption from liner material penetrating into the fuel at stagnation, and discuss the implications this has for how MagLif targets work and scale to larger drive currents. We then explore the extent to which different combinations of instability development, current delivery, high-Z mix into the fuel and initial laser deposition can be differentiated in our existing measurements. Better determining the dominant degradation mechanisms can directly influence the direction we take to improve performance, or our confidence in scaling these targets to higher currents. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. DoE's NNSA under contract DE-NA0003525.

Agricultural policies and biomass fuels

NASA Astrophysics Data System (ADS)

Flaim, S.; Hertzmark, D.

The potentials for biomass energy derived from agricultural products are examined. The production of energy feedstocks from grains is discussed for the example of ethanol production from grain, with consideration given to the beverage process and the wet milling process for obtaining fuel ethanol from grains and sugars, the nonfeedstock costs and energy requirements for ethanol production, the potential net energy gain from ethanol fermentation, the effect of ethanol fuel production on supplies of protein, oils and feed and of ethanol coproducts, net ethanol costs, and alternatives to corn as an ethanol feedstock. Biomass fuel production from crop residues is then considered; the constraints of soil fertility on crop residue removal for energy production are reviewed, residue yields with conventional practices and with reduced tillage are determined, technologies for the direct conversion of cellulose to ethanol and methanol are described, and potential markets for the products of these processes are identified. Implications for agricultural policy of ethanol production from grain and fuel and chemical production from crop residues are also discussed.

Root diseases in coniferous forests of the Inland West: potential implications of fuels treatments

Treesearch

Raini C. Rippy; Jane E. Stewart; Paul J. Zambino; Ned B. Klopfenstein; Joanne M. Tirocke; Mee-Sook Kim; Walter G. Thies

2005-01-01

After nearly 100 years of fire exclusion, introduced pests, and selective harvesting, a change in forest composition has occurred in many Inland West forests of North America. This change in forest structure has frequently been accompanied by increases in root diseases and/or an unprecedented buildup of fuels. Consequently, many forest managers are implementing plans...

Mimics and chameleons in motor neurone disease

PubMed Central

Turner, Martin R; Talbot, Kevin

2013-01-01

The progression of motor neurone disease (MND) is currently irreversible, and the grave implications of diagnosis naturally fuels concern among neurologists over missing a potential mimic disorder. There is no diagnostic test for MND but in reality there are few plausible mimics in routine clinical practice. In the presence of a progressive pure motor disorder, signs such as florid fasciculations, bilateral tongue wasting, the ‘split hand’, head drop, emotionality, and cognitive or behavioural impairment carry high positive predictive value. MND is clinically heterogeneous, however, with some important chameleon-like presentations and considerable variation in clinical course. Lack of confidence about the scope of such variation, or an approach to diagnosis emphasising investigations over clinical common sense, has the potential to exacerbate diagnostic delay in MND and impede timely planning of the care which is essential to maximising quality of life. PMID:23616620

Forum on energy conservation in buildings : implications for transportation

DOT National Transportation Integrated Search

1981-12-01

In a transportation-dependent society constrained by potential : shortages and the high costs of conventional fuels, as well as by : sometimes conflicting national objectives for increased energy : conservation, improved environmental quality, enhanc...

Will CNG threaten your future loads

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

A campaign to promote the use of natural gas as a fleet fuel is described and as a result, CNG conversions are beginning to take hold in some market segments. Only a few months after Ford Motor Co. announced production plans for an LPG-powered line of Granada/Cougar models, it unveiled an alternative-fuels concept car - a short-ranged metro sportscar - that could be ordered by the customer with any of four fuel systems (CNG, propane, ethanol, or methanol) offered on a dedicated or single-fuel basis. By including CNG in its alternative-fuels concept, Ford not only gave a boost to effortsmore » to build a motor fuel load for natural gas, but also indicated that CNG, as well as propane, is a viable alternative to gasoline in some applications. Recent reports of advances in CNG technology that enhance its potential as a motor fuel - together with other reports of at least one US firm launching production of a CNG motor fuel system and of several companies already marketing them - might be cause for the LPG industry to take another look at CNG's competitive potential.« less

Fuel Cell Seminar, 1992: Program and abstracts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-12-31

This year`s theme, ``Fuel Cells: Realizing the Potential,`` focuses on progress being made toward commercial manufacture and use of fuel cell products. Fuel cell power plants are competing for market share in some applications and demonstrations of market entry power plants are proceeding for additional applications. Development activity on fuel cells for transportation is also increasing; fuel cell products have potential in energy and transportation industries, with very favorable environmental impacts. This Seminar has the purpose of fostering communication by providing a forum for the international community interested in development, application, and business opportunities related fuel cells. Over 190 technicalmore » papers are included, the majority being processed for the data base.« less

The use of hydrogen for aircraft propulsion in view of the fuel crisis.

NASA Technical Reports Server (NTRS)

Weiss, S.

1973-01-01

In view of projected decreases in available petroleum fuels, interest has been generated in exploiting the potential of liquid hydrogen (LH2) as an aircraft fuel. Cost studies of LH2 production show it to be more expensive than presently used fuels. Regardless of cost considerations, LH2 is viewed as an attractive aircraft fuel because of the potential performance benefits it offers. Accompanying these benefits, however, are many new problems associated with aircraft design and operations; for example, problems related to fuel system design and the handling of LH2 during ground servicing. Some of the factors influencing LH2 fuel tank design, pumping, heat exchange, and flow regulation are discussed.

Indoor air quality for poor families: new evidence from Bangladesh.

PubMed

Dasgupta, S; Huq, M; Khaliquzzaman, M; Pandey, K; Wheeler, D

2006-12-01

Poor households in Bangladesh depend heavily on wood, dung and other biomass fuels for cooking. This paper provides a detailed analysis of the implications for indoor air pollution (IAP), drawing on new 24-h monitoring data for respirable airborne particulates (PM10). A stratified sample of 236 households was selected in Dhaka and Narayanganj, with a particular focus on fuel use, cooking locations, structural materials, ventilation practices, and other potential determinants of exposure to IAP. At each household, PM10 concentrations in the kitchen and living room were monitored for a 24-h period during December, 2003-February, 2004. Concentrations of 300 microg/m3 or greater are common in our sample, implying widespread exposure to a serious health hazard. A regression analysis for these 236 households was then conducted to explore the relationships between PM10 concentrations, fuel choices and a large set of variables that describe household cooking and ventilation practices, structure characteristics and building materials. As expected, our econometric results indicate that fuel choice significantly affects indoor pollution levels: natural gas and kerosene are significantly cleaner than biomass fuels. However, household-specific factors apparently matter more than fuel choice in determining PM10 concentrations. In some biomass-burning households, concentrations are scarcely higher than in households that use natural gas. Our results suggest that cross-household variation is strongly affected by structural arrangements: cooking locations, construction materials, and ventilation practices. A large variation in PM10 was also found during the 24-h cycle within households. For example, within the 'dirtiest' firewood-using household in our sample, readings over the 24-h cycle vary from 68 to 4864 microg/m3. Such variation occurs because houses can recycle air very quickly in Bangladesh. After the midday meal, when ventilation is common, air quality in many houses goes from very dirty to reasonably clean within an hour. Rapid change also occurs within households: diffusion of pollution from kitchens to living areas is nearly instantaneous in many cases, regardless of internal space configuration, and living-area concentrations are almost always in the same range as kitchen concentrations. By implication, exposure to dangerous indoor pollution levels is not confined to cooking areas. To assess the broader implications for poor Bangladeshi households, we extrapolate our regression results to representative 600 household samples from rural, peri-urban and urban areas in six regions: Rangpur in the north-west, Sylhet in the north-east, Rajshahi and Jessore in the west, Faridpur in the center, and Cox's Bazar in the south-east. Our results indicate great geographic variation, even for households in the same per capita income group. This variation reflects local differences in fuel use and, more significantly, construction practices that affect ventilation. For households with per capita income

Characterizing fuels in treated areas.

Treesearch

Roger D. Ottmar; Clinton S. Wright

2002-01-01

Small-log utilization or thinning operations followed by a fuel treatment such as prescribed fire can be used to change the composition and structure of fuelbeds, thereby mitigating deleterious fire effects and reducing the potential for catastrophic wildfires in some forested landscapes. We are developing a national system, Fuel Characteristic Classification (FCC),...

Alternate aircraft fuels: Prospects and operational implications

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1977-01-01

The potential use of coal-derived aviation fuels was assessed. The studies addressed the prices and thermal efficiencies associated with the production of coal-derived aviation kerosene, liquid methane and liquid hydrogen and the air terminal requirements and subsonic transport performance when utilizing liquid hydrogen. The fuel production studies indicated that liquid methane can be produced at a lower price and with a higher thermal efficiency than aviation kerosene or liquid hydrogen. Ground facilities of liquefaction, storage, distribution and refueling of liquid hydrogen fueled aircraft at airports appear technically feasibile. The aircraft studies indicate modest onboard energy savings for hydrogen compared to conventional fuels. Liquid hydrogen was found to be superior to both aviation kerosene and liquid methane from the standpoint of aircraft engine emissions.

Status of research into lightning effects on aircraft

NASA Technical Reports Server (NTRS)

Plumer, J. A.

1976-01-01

Developments in aircraft lightning protection since 1938 are reviewed. Potential lightning problems resulting from present trends toward the use of electronic controls and composite structures are discussed, along with presently available lightning test procedures for problem assessment. The validity of some procedures is being questioned because of pessimistic results and design implications. An in-flight measurement program is needed to provide statistics on lightning severity at flight altitudes and to enable more realistic tests, and operators are urged to supply researchers with more details on electronic components damaged by lightning strikes. A need for review of certain aspects of fuel system vulnerability is indicated by several recent accidents, and specific areas for examination are identified. New educational materials and standardization activities are also noted.

Characteristics of potential repository wastes. Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-07-01

The LWR spent fuels discussed in Volume 1 of this report comprise about 99% of all domestic non-reprocessed spent fuel. In this report we discuss other types of spent fuels which, although small in relative quantity, consist of a number of diverse types, sizes, and compositions. Many of these fuels are candidates for repository disposal. Some non-LWR spent fuels are currently reprocessed or are scheduled for reprocessing in DOE facilities at the Savannah River Site, Hanford Site, and the Idaho National Engineering Laboratory. It appears likely that the reprocessing of fuels that have been reprocessed in the past will continuemore » and that the resulting high-level wastes will become part of defense HLW. However, it is not entirely clear in some cases whether a given fuel will be reprocessed, especially in cases where pretreatment may be needed before reprocessing, or where the enrichment is not high enough to make reprocessing attractive. Some fuels may be canistered, while others may require special means of disposal. The major categories covered in this chapter include HTGR spent fuel from the Fort St. Vrain and Peach Bottom-1 reactors, research and test reactor fuels, and miscellaneous fuels, and wastes generated from the decommissioning of facilities.« less

100% Renewables as a Focus for Environmental Education

ERIC Educational Resources Information Center

Adlong, William

2012-01-01

The rapid development of renewable energy technologies has a number of implications for environmental educators and educators more generally. The costs of a number of renewable energy technologies are expected to be competitive with fossil fuels within 10-15 years and some installations are competitive already. From 2006-2011 global installations…

Microbial processes influencing the transport, fate and groundwater impacts of fuel ethanol releases.

PubMed

Ma, Jie; Rixey, William G; Alvarez, Pedro J J

2013-06-01

Fuel releases that impact groundwater are a common occurrence, and the growing use of ethanol as a transportation biofuel is increasing the likelihood of encountering ethanol in such releases. Microorganisms play a critical role in the fate of ethanol-blended fuel releases, often determining their region of influence and potential impacts. This review summarizes current understanding on the biogeochemical footprint of such releases and the factors that influence their natural attenuation. Implications for site investigation, risk assessment and remediation strategies are also addressed along with research priorities. Copyright © 2012 Elsevier Ltd. All rights reserved.

Clean fuels from biomass. [cellulose fermentation to methane

NASA Technical Reports Server (NTRS)

Hsu, Y. Y.

1974-01-01

The potential of growing crops as a source of fuels is examined, and it is shown that enough arable land is available in the U.S. so that, even with a modest rate of crop yield, the nation could be supplied by fuel crops. The technologies for fuel conversion are available; however, some R&D efforts are needed for scaling up design. Fuel crop economics are discussed and shown to be nonprohibitive.

Titanium dioxide in fuel cell technology: An overview

NASA Astrophysics Data System (ADS)

Abdullah, N.; Kamarudin, S. K.

2015-03-01

Fuel cell technology is one of the alternative energy sources for the next generation. Although this technology has proven to be one of the main methods for producing new energy sources, fuel cell technology still has some problems that hinder fuel cell commercialization. Recently, new ideas on titanium dioxide are introduced as potential solution in several applications in fuel cell technology. Thus, this article presents an overview on the applications of titanium dioxide and highlights the unique properties and benefits of titanium dioxide in fuel cell technology.

Liquid-phase penetration under unsteady in-cylinder conditions: Soy- and Cuphea-derived biodiesel fuels vs. conventional diesel

USDA-ARS?s Scientific Manuscript database

Accelerated dilution of engine-lubrication oil is a significant potential issue when fueling with biodiesel. Biodiesel produced from some feedstocks is less volatile than conventional diesel, which makes wall-impingement of liquid fuel more likely, a problem that could be exacerbated by advanced in...

Development of on-board fuel metering and sensing system

NASA Astrophysics Data System (ADS)

Hemanth, Y.; Manikanta, B. S. S.; Thangaraja, J.; Bharanidaran, R.

2017-11-01

Usage of biodiesel fuels and their blends with diesel fuel has a potential to reduce the tailpipe emissions and reduce the dependence on crude oil imports. Further, biodiesel fuels exhibit favourable greenhouse gas emission and energy balance characteristics. While fossil fuel technology is well established, the technological implications of biofuels particularly biodiesel is not clearly laid out. Hence, the objective is to provide an on-board metering control in selecting the different proportions of diesel and bio-diesel blends. An on-board fuel metering system is being developed using PID controller, stepper motors and a capacitance sensor. The accuracy was tested with the blends of propanol-1, diesel and are found to be within 1.3% error. The developed unit was tested in a twin cylinder diesel engine with biodiesel blended diesel fuel. There was a marginal increase (5%) in nitric oxide and 14% increase in smoke emission with 10% biodiesel blended diesel at part load conditions.

Potential synergy: the thorium fuel cycle and rare earths processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ault, T.; Wymer, R.; Croff, A.

2013-07-01

The use of thorium in nuclear power programs has been evaluated on a recurring basis. A concern often raised is the lack of 'thorium infrastructure'; however, for at least a part of a potential thorium fuel cycle, this may less of a problem than previously thought. Thorium is frequently encountered in association with rare earth elements and, since the U.S. last systematically evaluated the large-scale use of thorium (the 1970's,) the use of rare earth elements has increased ten-fold to approximately 200,000 metric tons per year. Integration of thorium extraction with rare earth processing has been previously described and top-levelmore » estimates have been done on thorium resource availability; however, since ores and mining operations differ markedly, what is needed is process flowsheet analysis to determine whether a specific mining operation can feasibly produce thorium as a by-product. Also, the collocation of thorium with rare earths means that, even if a thorium product stream is not developed, its presence in mining waste streams needs to be addressed and there are previous instances where this has caused issues. This study analyzes several operational mines, estimates the mines' ability to produce a thorium by-product stream, and discusses some waste management implications of recovering thorium. (authors)« less

Implications of fire management on cultural resources [Chapter 9

Treesearch

Rebecca S. Timmons; Leonard deBano; Kevin C. Ryan

2012-01-01

Previous chapters in this synthesis have identified the important fuel, weather, and fire relationships associated with damage to cultural resources (CR). They have also identified the types of effects commonly encountered in various fire situations and provided some guidance on how to recognize damages and minimize their occurrence. This chapter describes planning...

Air transportation energy efficiency - Alternatives and implications

NASA Technical Reports Server (NTRS)

Williams, L. J.

1976-01-01

Results from recent studies of air transportation energy efficiency alternatives are discussed, along with some of the implications of these alternatives. The fuel-saving alternatives considered include aircraft operation, aircraft modification, derivative aircraft, and new aircraft. In the near-term, energy efficiency improvements should be possible through small improvements in fuel-saving flight procedures, higher density seating, and higher load factors. Additional small near-term improvements could be obtained through aircraft modifications, such as the relatively inexpensive drag reduction modifications. Derivatives of existing aircraft could meet the requirements for new aircraft and provide energy improvements until advanced technology is available to justify the cost of a completely new design. In order to obtain significant improvements in energy efficiency, new aircraft must truly exploit advanced technology in such areas as aerodynamics, composite structures, active controls, and advanced propulsion.

Feasibility and Design Implications of Fuel Cell Power for Sealift Ships

DTIC Science & Technology

2010-01-01

Feasibility and Design Implications of Fuel Cell Power for Sealift Ships Jing Suna, John Stebeb, and Colen Kennellb a Department of Naval...studies published so far have focused on ship service power or on propulsion power for small vessels with moderate power requirements. Using a ... a large military cargo ship. A notional solid oxide fuel cell (SOFC) module is proposed and the implications of the technology on fuel savings and

Liquid phase products and solid deposit formation from thermally stressed model jet fuels

NASA Technical Reports Server (NTRS)

Kim, W. S.; Bittker, D. A.

1984-01-01

The relationship between solid deposit formation and liquid degradation product concentration was studied for the high temperature (400 C) stressing of three hydrocarbon model fuels. A Jet Fuel Thermal Oxidation Tester was used to simulate actual engine fuel system conditions. The effects of fuel type, dissolved oxygen concentration, and hot surface contact time (reaction time) were studied. Effects of reaction time and removal of dissolved oxygen on deposit formation were found to be different for n-dodecane and for 2-ethylnaphthalene. When ten percent tetralin is added to n-dodecane to give a simpler model of an actual jet fuel, the tetralin inhibits both the deposit formation and the degradation of n-dodecane. For 2-ethylnaphthalene primary product analyses indicate a possible self-inhibition at long reaction times of the secondary reactions which form the deposit precursors. The mechanism of the primary breakdown of these fuels is suggested and the primary products which participate in these precursor-forming reactions are identified. Some implications of the results to the thermal degradation of real jet fuels are given.

Marine applications for fuel cell technology: A technical memorandum

NASA Astrophysics Data System (ADS)

1986-02-01

To date, almost no attention was given to the potential marine applications for fuel cell technologies. Some of the benefits that fuel cells may offer to the utility industry may also apply to marine use. At a 1 day workshop the Office of Technology Assessment found fuel cells to offer advantages in applications requiring quiet operations, applications where throttle settings are constantly changed, and for small submarines. Fuel cells are not expected to penetrate marine markets until they become firmly established in the commercial utility section.

Nuclear Energy Advanced Modeling and Simulation (NEAMS) Accident Tolerant Fuels High Impact Problem: Coordinate Multiscale U 3Si 2 Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gamble, K. A.; Hales, J. D.; Miao, Y.

Since the events at the Fukushima-Daiichi nuclear power plant in March 2011 significant research has unfolded at national laboratories, universities and other institutions into alternative materials that have potential enhanced accident tolerance when compared to traditional \\uo~fuel zircaloy clad fuel rods. One of the potential replacement fuels is uranium silicide (\\usi) for its higher thermal conductivity and uranium density. The lower melting temperature is of potential concern during postulated accident conditions. Another disadvantage for \\usi~ is the lack of experimental data under power reactor conditions. Due to the aggressive development schedule for inserting some of the potential materials into leadmore » test assemblies or rods by 2022~\\cite{bragg-sitton_2014} multiscale multiphysics modeling approaches have been used to provide insight into these materials. \\\\ \

Assessing the Global Potential and Regional Implications of Promoting Bioenergy

EPA Science Inventory

There is no simple answer to the question “are materials from bio-based feedstocks environmentally, and socially, preferable?” Bioenergy as an alternative energy source might be effective in reducing fossil fuel use, slowing global warming effects, and providing increased revenue...

Assessing the global potential and regional implications of promoting bio-energy

EPA Science Inventory

There is no simple answer to the question “are materials from bio-based feedstocks environmentally, and socially, preferable?” Bioenergy as an alternative energy source might be effective in reducing fossil fuel use, slowing global warming effects, and providing increased revenue...

The fractalline properties of experimentally simulated PWR fuel crud

NASA Astrophysics Data System (ADS)

Dumnernchanvanit, I.; Mishra, V. K.; Zhang, N. Q.; Robertson, S.; Delmore, A.; Mota, G.; Hussey, D.; Wang, G.; Byers, W. A.; Short, M. P.

2018-02-01

The buildup of fouling deposits on nuclear fuel rods, known as crud, continues to challenge the worldwide fleet of light water reactors (LWRs). Crud may cause serious operational problems for LWRs, including axial power shifts, accelerated fuel clad corrosion, increased primary circuit radiation dose rates, and in some instances has led directly to fuel failure. Numerous studies continue to attempt to model and predict the effects of crud, but each makes critical assumptions regarding how to treat the complex, porous microstructure of crud and its resultant effects on temperature, pressure, and crud chemistry. In this study, we demonstrate that crud is indeed a fractalline porous medium using flowing loop experiments, validating the most recent models of its effects on LWR fuel cladding. This crud is shown to match that in other LWR-prototypical facilities through a porosity-fractal dimension scaling law. Implications of this result range from post-mortem analysis of the effects of crud on reactor fuel performance, to utilizing crud's fractalline dimensions to quantify the effectiveness of anti-fouling measures.

Artificial Photosystem I and II: Highly Selective solar fuels and tandem photocatalysis

NASA Astrophysics Data System (ADS)

Ding, Yuchen; Castellanos, Ignacio; Cerkovnik, Logan; Nagpal, Prashant

2014-03-01

Artificial photosynthesis, or generation of solar fuels from CO2/H2O, can provide an important alternative for rising CO2 emission and renewable energy generation. In our recent work, composite photocatalysts (CPCs) made from widebandgap nanotubes and different QDs were used to mimic Photosystem II (PS680) and I (PS700), respectively. By tuning the redox potentials using the size, composition and energy band alignment of QDs, we demonstrate highly selective (>90%) and efficient production of ethane, ethanol and acetaldehyde as solar fuels with different wavelengths of light. We also show that this selectivity is a result of precise energy band alignments (using cationic/anionic doping of nanotubes, QD size etc.), confirmed using measurements of electronic density of states, and alignment of higher redox potentials with hot-carriers can also lead to hot-carrier photocatalysis. This wavelength-selective CPCs can have important implications for inexpensive production of solar fuels including alkanes, alcohols, aldehydes and hydrogen, and making tandem structures (red, green, blue) with three CPCs, allowing almost full visible spectrum (410 ~ 730nm) utilization with different fuels produced simultaneously.

Ethanol distribution, dispensing, and use: analysis of a portion of the biomass-to-biofuels supply chain using system dynamics.

PubMed

Vimmerstedt, Laura J; Bush, Brian; Peterson, Steve

2012-01-01

The Energy Independence and Security Act of 2007 targets use of 36 billion gallons of biofuels per year by 2022. Achieving this may require substantial changes to current transportation fuel systems for distribution, dispensing, and use in vehicles. The U.S. Department of Energy and the National Renewable Energy Laboratory designed a system dynamics approach to help focus government action by determining what supply chain changes would have the greatest potential to accelerate biofuels deployment. The National Renewable Energy Laboratory developed the Biomass Scenario Model, a system dynamics model which represents the primary system effects and dependencies in the biomass-to-biofuels supply chain. The model provides a framework for developing scenarios and conducting biofuels policy analysis. This paper focuses on the downstream portion of the supply chain-represented in the distribution logistics, dispensing station, and fuel utilization, and vehicle modules of the Biomass Scenario Model. This model initially focused on ethanol, but has since been expanded to include other biofuels. Some portions of this system are represented dynamically with major interactions and feedbacks, especially those related to a dispensing station owner's decision whether to offer ethanol fuel and a consumer's choice whether to purchase that fuel. Other portions of the system are modeled with little or no dynamics; the vehicle choices of consumers are represented as discrete scenarios. This paper explores conditions needed to sustain an ethanol fuel market and identifies implications of these findings for program and policy goals. A large, economically sustainable ethanol fuel market (or other biofuel market) requires low end-user fuel price relative to gasoline and sufficient producer payment, which are difficult to achieve simultaneously. Other requirements (different for ethanol vs. other biofuel markets) include the need for infrastructure for distribution and dispensing and widespread use of high ethanol blends in flexible-fuel vehicles.

Ethanol Distribution, Dispensing, and Use: Analysis of a Portion of the Biomass-to-Biofuels Supply Chain Using System Dynamics

PubMed Central

Vimmerstedt, Laura J.; Bush, Brian; Peterson, Steve

2012-01-01

The Energy Independence and Security Act of 2007 targets use of 36 billion gallons of biofuels per year by 2022. Achieving this may require substantial changes to current transportation fuel systems for distribution, dispensing, and use in vehicles. The U.S. Department of Energy and the National Renewable Energy Laboratory designed a system dynamics approach to help focus government action by determining what supply chain changes would have the greatest potential to accelerate biofuels deployment. The National Renewable Energy Laboratory developed the Biomass Scenario Model, a system dynamics model which represents the primary system effects and dependencies in the biomass-to-biofuels supply chain. The model provides a framework for developing scenarios and conducting biofuels policy analysis. This paper focuses on the downstream portion of the supply chain–represented in the distribution logistics, dispensing station, and fuel utilization, and vehicle modules of the Biomass Scenario Model. This model initially focused on ethanol, but has since been expanded to include other biofuels. Some portions of this system are represented dynamically with major interactions and feedbacks, especially those related to a dispensing station owner’s decision whether to offer ethanol fuel and a consumer’s choice whether to purchase that fuel. Other portions of the system are modeled with little or no dynamics; the vehicle choices of consumers are represented as discrete scenarios. This paper explores conditions needed to sustain an ethanol fuel market and identifies implications of these findings for program and policy goals. A large, economically sustainable ethanol fuel market (or other biofuel market) requires low end-user fuel price relative to gasoline and sufficient producer payment, which are difficult to achieve simultaneously. Other requirements (different for ethanol vs. other biofuel markets) include the need for infrastructure for distribution and dispensing and widespread use of high ethanol blends in flexible-fuel vehicles. PMID:22606230

Integrating social and value dimensions into sustainability assessment of lignocellulosic biofuels

PubMed Central

Raman, Sujatha; Mohr, Alison; Helliwell, Richard; Ribeiro, Barbara; Shortall, Orla; Smith, Robert; Millar, Kate

2015-01-01

The paper clarifies the social and value dimensions for integrated sustainability assessments of lignocellulosic biofuels. We develop a responsible innovation approach, looking at technology impacts and implementation challenges, assumptions and value conflicts influencing how impacts are identified and assessed, and different visions for future development. We identify three distinct value-based visions. From a techno-economic perspective, lignocellulosic biofuels can contribute to energy security with improved GHG implications and fewer sustainability problems than fossil fuels and first-generation biofuels, especially when biomass is domestically sourced. From socio-economic and cultural-economic perspectives, there are concerns about the capacity to support UK-sourced feedstocks in a global agri-economy, difficulties monitoring large-scale supply chains and their potential for distributing impacts unfairly, and tensions between domestic sourcing and established legacies of farming. To respond to these concerns, we identify the potential for moving away from a one-size-fits-all biofuel/biorefinery model to regionally-tailored bioenergy configurations that might lower large-scale uses of land for meat, reduce monocultures and fossil-energy needs of farming and diversify business models. These configurations could explore ways of reconciling some conflicts between food, fuel and feed (by mixing feed crops with lignocellulosic material for fuel, combining livestock grazing with energy crops, or using crops such as miscanthus to manage land that is no longer arable); different bioenergy applications (with on-farm use of feedstocks for heat and power and for commercial biofuel production); and climate change objectives and pressures on farming. Findings are based on stakeholder interviews, literature synthesis and discussions with an expert advisory group. PMID:26664147

Integrating social and value dimensions into sustainability assessment of lignocellulosic biofuels.

PubMed

Raman, Sujatha; Mohr, Alison; Helliwell, Richard; Ribeiro, Barbara; Shortall, Orla; Smith, Robert; Millar, Kate

2015-11-01

The paper clarifies the social and value dimensions for integrated sustainability assessments of lignocellulosic biofuels. We develop a responsible innovation approach, looking at technology impacts and implementation challenges, assumptions and value conflicts influencing how impacts are identified and assessed, and different visions for future development. We identify three distinct value-based visions. From a techno-economic perspective, lignocellulosic biofuels can contribute to energy security with improved GHG implications and fewer sustainability problems than fossil fuels and first-generation biofuels, especially when biomass is domestically sourced. From socio-economic and cultural-economic perspectives, there are concerns about the capacity to support UK-sourced feedstocks in a global agri-economy, difficulties monitoring large-scale supply chains and their potential for distributing impacts unfairly, and tensions between domestic sourcing and established legacies of farming. To respond to these concerns, we identify the potential for moving away from a one-size-fits-all biofuel/biorefinery model to regionally-tailored bioenergy configurations that might lower large-scale uses of land for meat, reduce monocultures and fossil-energy needs of farming and diversify business models. These configurations could explore ways of reconciling some conflicts between food, fuel and feed (by mixing feed crops with lignocellulosic material for fuel, combining livestock grazing with energy crops, or using crops such as miscanthus to manage land that is no longer arable); different bioenergy applications (with on-farm use of feedstocks for heat and power and for commercial biofuel production); and climate change objectives and pressures on farming. Findings are based on stakeholder interviews, literature synthesis and discussions with an expert advisory group.

U.S.-South Korea Relations

DTIC Science & Technology

2013-04-26

reprocessed to make new fuel using a type of reprocessing called pyroprocessing .66 The United States and South Korea are jointly researching pyroprocessing ...solutions to spent fuel disposal. Spent fuel disposal is a key policy issue for South Korean officials, and some see pyroprocessing as a potential solution...proponents of pyroprocessing see it as a way to advance energy independence for South Korea. 66

Temperatures below leaf litter during winter prescribed burns: implications for litter-roosting bats

Treesearch

Roger W. Perry; Virginia L. McDaniel

2015-01-01

Some bat species, including eastern red bats (Lasiurus borealis), roost for short periods beneath leaf litter on the forest floor during winter in the south-eastern USA, a region subjected to frequent fire. The variability in fuel consumption, the heterogeneous nature of burns, and the effects of litter and duff moisture on forest-floor...

Transition to Ultra-Low-Sulfur Diesel Fuel: Effects on Prices and Supply, The

EIA Publications

2001-01-01

This report discusses the implications of the new regulations for vehicle fuel efficiency and examines the technology, production, distribution, and cost implications of supplying diesel fuel to meet the new standards.

Family environmental and dietary implications for low-level prenatal lead exposure in Wujiang City, China.

PubMed

Yan, Jin; Gao, Zhenyan; Wang, Ju; Ma, Wenjuan; Ying, Xiaolan; Zhou, Cancan; Yan, Chonghuai

2018-05-01

To explore the potential environmental and dietary factors during pregnancy affecting low-level prenatal lead exposure, we conducted a longitudinal study in Wujiang City, China. A total of 1976 mother-infant pairs were included from 2009 to 2010. An interviewed questionnaire was conducted and cord blood samples were collected. The geometric means of cord blood lead level was 30.3 μg/L (95% CI, 29.8-30.8) with 99.24% below 100 μg/L. Maternal age, passive smoking, and living in the countryside were significantly associated with cord blood lead concentrations. Multiple logistic models showed that some family environmental factors including using firewood and electricity as kitchen fuel were positively correlated with increased cord blood lead levels. Among dietary sources recorded in this study, meat consumption (> 3 times/week), fish consumption (1-3 times/week), vegetables consumption (> 1 times/day), and fruit intake (> 1 times/day) had inverse relationship with cord blood lead levels. In general, our findings may have important implications for family environmental and dietary direction during pregnancy to decrease prenatal lead exposure.

Fuel Cells: A Real Option for Unmanned Aerial Vehicles Propulsion

PubMed Central

2014-01-01

The possibility of implementing fuel cell technology in Unmanned Aerial Vehicle (UAV) propulsion systems is considered. Potential advantages of the Proton Exchange Membrane or Polymer Electrolyte Membrane (PEMFC) and Direct Methanol Fuel Cells (DMFC), their fuels (hydrogen and methanol), and their storage systems are revised from technical and environmental standpoints. Some operating commercial applications are described. Main constraints for these kinds of fuel cells are analyzed in order to elucidate the viability of future developments. Since the low power density is the main problem of fuel cells, hybridization with electric batteries, necessary in most cases, is also explored. PMID:24600326

Purpose and applications [Chapter 1

Treesearch

Nicholas L. Crookston

2003-01-01

The Fire and Fuels Extension (FFE) to the Forest Vegetation Simulator (FVS) simulates fuel dynamics and potential fire behavior over time, in the context of stand development and management. This chapter provides an introduction to the model by illustrating its purpose and chronicling some of the applications it has supported.

Safety consequences of local initiating events in an LMFBR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, R.M.; Marr, W.W.; Padilla, A. Jr.

1975-12-01

The potential for fuel-failure propagation in an LMFBR at or near normal conditions is examined. Results are presented to support the conclusion that although individual fuel-pin failure may occur, rapid failure-propagation spreading among a large number of fuel pins in a subassembly is unlikely in an operating LMFBR. This conclusion is supported by operating experience, mechanistic analyses of failure-propagation phenomena, and experiments. In addition, some of the consequences of continued operation with defected fuel are considered.

PLUTONIUM METALLIC FUELS FOR FAST REACTORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

STAN, MARIUS; HECKER, SIEGFRIED S.

2007-02-07

Early interest in metallic plutonium fuels for fast reactors led to much research on plutonium alloy systems including binary solid solutions with the addition of aluminum, gallium, or zirconium and low-melting eutectic alloys with iron and nickel or cobalt. There was also interest in ternaries of these elements with plutonium and cerium. The solid solution and eutectic alloys have most unusual properties, including negative thermal expansion in some solid-solution alloys and the highest viscosity known for liquid metals in the Pu-Fe system. Although metallic fuels have many potential advantages over ceramic fuels, the early attempts were unsuccessful because these fuelsmore » suffered from high swelling rates during burn up and high smearing densities. The liquid metal fuels experienced excessive corrosion. Subsequent work on higher-melting U-PuZr metallic fuels was much more promising. In light of the recent rebirth of interest in fast reactors, we review some of the key properties of the early fuels and discuss the challenges presented by the ternary alloys.« less

Recent Immigrant Settlement in the Nonmetropolitan United States: Evidence from Internal Census Data

ERIC Educational Resources Information Center

Donato, Katharine M.; Tolbert, Charles M., II; Nucci, Alfred; Kawano, Yukio

2007-01-01

In the 1990s, studies have documented widespread growth of immigrants in U.S. communities not known as common destinations in the past. This trend has fueled population growth in some nonmetropolitan areas and offset population decline in other areas. In this paper, we examine the implications of recent foreign born in-migration for rural America.…

Limitations of Commercializing Fuel Cell Technologies

NASA Astrophysics Data System (ADS)

Nordin, Normayati

2010-06-01

Fuel cell is the technology that, nowadays, is deemed having a great potential to be used in supplying energy. Basically, fuel cells can be categorized particularly by the kind of employed electrolyte. Several fuel cells types which are currently identified having huge potential to be utilized, namely, Solid Oxide Fuel Cells (SOFC), Molten Carbonate Fuel Cells (MCFC), Alkaline Fuel Cells (AFC), Phosphoric Acid Fuel Cells (PAFC), Polymer Electron Membrane Fuel Cell (PEMFC), Direct Methanol Fuel Cells (DMFC) and Regenerative Fuel Cells (RFC). In general, each of these fuel cells types has their own characteristics and specifications which assign the capability and suitability of them to be utilized for any particular applications. Stationary power generations and transport applications are the two most significant applications currently aimed for the fuel cell market. It is generally accepted that there are lots of advantages if fuel cells can be excessively commercialized primarily in context of environmental concerns and energy security. Nevertheless, this is a demanding task to be accomplished, as there is some gap in fuel cells technology itself which needs a major enhancement. It can be concluded, from the previous study, cost, durability and performance are identified as the main limitations to be firstly overcome in enabling fuel cells technology become viable for the market.

Life Cycle Assessment of Cookstoves and Fuels in India ...

EPA Pesticide Factsheets

This presentation was requested by the Global Alliance to augment they scheduled to present update on the use of LCA to better understand implications of future policy that consider all pollutants including criteria, air toxics, and other pollutants impacting air quality concerns in these countries. EPA research quantitatively demonstrates through the application of LCA that both cooking fuel mix substitutions and stove technology upgrades provide promising avenues for reducing particulate matter and black carbon emissions. India’s continued reliance on crop residue and dung contributes disproportionately to particulate matter and black carbon environmental impacts. The greatest environmental benefit in China can be realized by promoting fuel mix substitutions or stove technology improvements to replace the combustion of coal powder in traditional stoves. Kenya and Ghana would benefit from adoption of improved stove designs for both firewood and charcoal fuel. Use of improved charcoal kiln technology also has the potential to significantly reduce the impact of charcoal use and production. The study generally demonstrates the positive relative environmental results associated with LPG and natural gas, which show a limited tendency to shift environmental burdens away from indoor air pollutants and to other impact categories such as fossil fuel depletion, freshwater eutrophication, and terrestrial acidification potential when substituted for traditional fuels. T

Essays on alternative energy policies affecting the US transportation sector

NASA Astrophysics Data System (ADS)

O'Rear, Eric G.

This dissertation encompasses three essays evaluating the impacts of different policies targeting the greenhouse gas (GHG) emissions, fuel demands, etc. of the transportation sector. Though there are some similarities across the three chapters, each essay stands alone as an independent work. The 2010 US EPA MARKAL model is used in each essay to evaluate policy effects. Essay 1 focuses on the recent increases in Corporate Average Fuel Economy (CAFE) standards, and the implications of a "rebound effect." These increases are compared to a carbon tax generating similar reductions in system-wide emissions. As anticipated, the largest reductions in fuel use by light-duty vehicles (LDV) and emissions are achieved under CAFE. Consideration of the rebound effect does little to distort CAFE benefits. Our work validates many economists' belief that a carbon tax is a more efficient approach. However, because the tax takes advantage of cheaper abatement opportunities in other sectors, reductions in transportation emissions will be much lower than what we observe with CAFE. Essay 2 compares CAFE increases with what some economists suggest would be a much more "efficient" alternative -- a system-wide oil tax internalizing some environmental externalities. Because oil taxes are likely to be implemented in addition to CAFE standards, we consider a combined policy case reflecting this. Our supplementary analysis approximates the appropriate tax rates to produce similar reductions in oil demands as CAFE (CAFE-equivalent tax rates). We discover that taxes result in greater and more cost-effective reductions in system-wide emissions and net oil imports than CAFE. The current fuel tax system is compared to three versions of a national vehicle miles traveled (VMT) tax charged to all LDVs in Essay 3. VMT taxes directly charge motorists for each mile driven and help to correct the problem of eroding tax revenues given the failure of today's fuel taxes to adjust with inflation. Results suggest that VMT taxes generate more revenue than our existing fuel tax structure, but do so at the expense of the LDV fleet becoming less fuel-inefficient. If stringent enough, VMT taxes can lead to some rather noticeable reductions in miles driven, fuel use, and emissions.

Implications of Outside-the-Box Technologies on Future Space Exploration and Colonization

NASA Astrophysics Data System (ADS)

Loder, Theodore C.

2003-01-01

In general, planning for future manned space exploration either to the moon, Mars, or an asteroid has depended on a somewhat linear extrapolation of our present technologies. Two major prohibitive cost issues regarding such planning are payload lift and in-flight energy generation. The costs of these in both engineering and actual flight costs, coupled with the planning necessary to carry out such exploration have prevented us from actively moving forward. Although, it will be worthwhile to continue to plan for such exploration using ``present'' technologies, I recommend that planning be concerned mainly with mission strategies and goals utilizing both present technology and totally new energy breakthroughs. There are presently in research and development an entire suite of relevant outside-the-box technologies which will include both zero point energy generation and antigravity technologies that will replace our present solar/nuclear/fuel cell energy technologies and liquid/solid fuel rockets. This paper describes some of these technologies, the physics behind them and their potential use for manned space exploration. The companies and countries that first incorporate these technologies into their space programs will lead the way in exploring and colonizing space.

AN INTEGRATED ASSESSMENT OF THE IMPACTS OF HYDROGEN ECONOMY ON TRANSPORTATION, ENERGY USE, AND AIR EMISSIONS

EPA Science Inventory

This paper presents an analysis of the potential energy, economic and environmental implications of hydrogen fuel cell vehicle (H2-FCV) penetration into the U.S. light duty vehicle fleet. The approach, which uses the U.S. EPA MARKet ALlocation technology database and model, allow...

Mobility Fuels for the Navy.

DTIC Science & Technology

1982-01-01

aircraft powered by gas turbines through the year 2000. The study also predicted that some types of diesels and steam powerplants could potentially...figure 3. Diesels are more efficient even at high- power settings. CHANGES TO FUELS Interrelationships between the price and quality of fuel have...emaIcal Physics 20 (1979) pp. 6446- PP 252 899), AD) A061 938 Nunn, Wolter R.. -Poeltion Finding with Prior Kowledge of .Eonrience Parameters," 5 pp., Jun

Mechanosensing Potentials Gate Fuel Consumption in a Bipedal DNA Nanowalker

NASA Astrophysics Data System (ADS)

Tee, Shern Ren; Hu, Xinpeng; Loh, Iong Ying; Wang, Zhisong

2018-03-01

A bipedal DNA nanowalker was recently reported to convert chemical energy into directional motion autonomously and efficiently. To elucidate its chemomechanical coupling mechanisms, three-dimensional molecular modeling is used to obtain coarse-grained foot-track binding potentials of the DNA nanowalker via unbiased and biased sampling techniques (for the potentials' basin and high-energy edges, respectively). The binding state that is protected against fuel-induced dissociation responds asymmetrically to forward versus backward forces, unlike the unprotected state, demonstrating a mechanosensing capability to gate fuel binding. Despite complex DNA mechanics, the foot-track potential exhibits a surprisingly neat three-part profile, offering some general guidelines to rationally design efficient nanowalkers. Subsequent modeling of the bipedal walker attached to the track gives estimates of the free energy for each bipedal state, showing how the mechanosensing foot-track binding breaks the symmetry between the rear and front feet, enabling the rear foot to be selectively dissociated by fuel and generating efficient chemomechanical coupling.

Logistics and Capability Implications of a Bradley Fighting Vehicle with a Fuel Cell Auxiliary Power Unit

DTIC Science & Technology

2003-10-13

04ANNUAL-524 Logistics and Capability Implications of a Bradley Fighting Vehicle with a Fuel Cell Auxiliary Power Unit Joseph Conover, Harry...used or the main engines are restarted. Integration of a solid oxide fuel cell (SOFC) auxiliary power unit into a military vehicle has the...presented which show the fuel usage and capability impacts of incorporating a fuel cell APU into the electrical system of a Bradley M2A3 Diesel

Mutagenicity and Lung Toxicity of Smoldering vs. Flaming Emissions from Various Biomass Fuels: Implications for Health Effects from Wildland Fires.

PubMed

Kim, Yong Ho; Warren, Sarah H; Krantz, Q Todd; King, Charly; Jaskot, Richard; Preston, William T; George, Barbara J; Hays, Michael D; Landis, Matthew S; Higuchi, Mark; DeMarini, David M; Gilmour, M Ian

2018-01-24

The increasing size and frequency of wildland fires are leading to greater potential for cardiopulmonary disease and cancer in exposed populations; however, little is known about how the types of fuel and combustion phases affect these adverse outcomes. We evaluated the mutagenicity and lung toxicity of particulate matter (PM) from flaming vs. smoldering phases of five biomass fuels, and compared results by equal mass or emission factors (EFs) derived from amount of fuel consumed. A quartz-tube furnace coupled to a multistage cryotrap was employed to collect smoke condensate from flaming and smoldering combustion of red oak, peat, pine needles, pine, and eucalyptus. Samples were analyzed chemically and assessed for acute lung toxicity in mice and mutagenicity in Salmonella . The average combustion efficiency was 73 and 98% for the smoldering and flaming phases, respectively. On an equal mass basis, PM from eucalyptus and peat burned under flaming conditions induced significant lung toxicity potencies (neutrophil/mass of PM) compared to smoldering PM, whereas high levels of mutagenicity potencies were observed for flaming pine and peat PM compared to smoldering PM. When effects were adjusted for EF, the smoldering eucalyptus PM had the highest lung toxicity EF (neutrophil/mass of fuel burned), whereas smoldering pine and pine needles had the highest mutagenicity EF. These latter values were approximately 5, 10, and 30 times greater than those reported for open burning of agricultural plastic, woodburning cookstoves, and some municipal waste combustors, respectively. PM from different fuels and combustion phases have appreciable differences in lung toxic and mutagenic potency, and on a mass basis, flaming samples are more active, whereas smoldering samples have greater effect when EFs are taken into account. Knowledge of the differential toxicity of biomass emissions will contribute to more accurate hazard assessment of biomass smoke exposures. https://doi.org/10.1289/EHP2200.

Acute nutritional ketosis: implications for exercise performance and metabolism

PubMed Central

2014-01-01

Ketone bodies acetoacetate (AcAc) and D-β-hydroxybutyrate (βHB) may provide an alternative carbon source to fuel exercise when delivered acutely in nutritional form. The metabolic actions of ketone bodies are based on sound evolutionary principles to prolong survival during caloric deprivation. By harnessing the potential of these metabolic actions during exercise, athletic performance could be influenced, providing a useful model for the application of ketosis in therapeutic conditions. This article examines the energetic implications of ketone body utilisation with particular reference to exercise metabolism and substrate energetics. PMID:25379174

Meta-analysis and Harmonization of Life Cycle Assessment Studies for Algae Biofuels.

PubMed

Tu, Qingshi; Eckelman, Matthew; Zimmerman, Julie

2017-09-05

Algae biodiesel (BioD) and renewable diesel (RD) have been recognized as potential solutions to mitigating fossil-fuel consumption and the associated environmental issues. Life cycle assessment (LCA) has been used by many researchers to evaluate the potential environmental impacts of these algae-derived fuels, yielding a wide range of results and, in some cases, even differing on indicating whether these fuels are preferred to petroleum-derived fuels or not. This meta-analysis reviews the methodological preferences and results for energy consumption, greenhouse gas emissions, and water consumption for 54 LCA studies that considered algae BioD and RD. The significant variation in reported results can be primarily attributed to the difference in scope, assumptions, and data sources. To minimize the variation in life cycle inventory calculations, a harmonized inventory data set including both nominal and uncertainty data is calculated for each stage of the algae-derived fuel life cycle.

Characteristics people consider when evaluating forest landscape attractiveness: fuel management implications

Treesearch

Melinda Merrick; Joanne Vining

2006-01-01

In this study, we were able to gain a better understanding of which elements people observe when they are making decisions about the relative attractiveness of a forest. Of primary consideration to participants were the specific characteristics of the vegetation, especially forest health, and the experiential potential for the forest scenes. Participants fairly often...

Biomass and nitrogen dynamics of four plantation tree species receiving irrigation and fertilization

Treesearch

W. Rusty Cobb; Rodney E. Will; Richard F. Daniels; Marshall A. Jacobson

2010-01-01

In addition to fiber and wood production, there has been renewed interest in using forest biomass for energy production through both direct combustion and through technologies to produce liquid fuels from wood. In addition, growth and productivity of forests have important potential implications in terms of carbon sequestration and carbon credits because growth is...

Solid Fuel Use for Household Cooking: Country and Regional Estimates for 1980–2010

PubMed Central

Bonjour, Sophie; Adair-Rohani, Heather; Wolf, Jennyfer; Bruce, Nigel G.; Mehta, Sumi; Lahiff, Maureen; Rehfuess, Eva A.; Mishra, Vinod; Smith, Kirk R.

2013-01-01

Background: Exposure to household air pollution from cooking with solid fuels in simple stoves is a major health risk. Modeling reliable estimates of solid fuel use is needed for monitoring trends and informing policy. Objectives: In order to revise the disease burden attributed to household air pollution for the Global Burden of Disease 2010 project and for international reporting purposes, we estimated annual trends in the world population using solid fuels. Methods: We developed a multilevel model based on national survey data on primary cooking fuel. Results: The proportion of households relying mainly on solid fuels for cooking has decreased from 62% (95% CI: 58, 66%) to 41% (95% CI: 37, 44%) between 1980 and 2010. Yet because of population growth, the actual number of persons exposed has remained stable at around 2.8 billion during three decades. Solid fuel use is most prevalent in Africa and Southeast Asia where > 60% of households cook with solid fuels. In other regions, primary solid fuel use ranges from 46% in the Western Pacific, to 35% in the Eastern Mediterranean and < 20% in the Americas and Europe. Conclusion: Multilevel modeling is a suitable technique for deriving reliable solid-fuel use estimates. Worldwide, the proportion of households cooking mainly with solid fuels is decreasing. The absolute number of persons using solid fuels, however, has remained steady globally and is increasing in some regions. Surveys require enhancement to better capture the health implications of new technologies and multiple fuel use. PMID:23674502

Influence of methane emissions and vehicle efficiency on the climate implications of heavy-duty natural gas trucks.

PubMed

Camuzeaux, Jonathan R; Alvarez, Ramón A; Brooks, Susanne A; Browne, Joshua B; Sterner, Thomas

2015-06-02

While natural gas produces lower carbon dioxide emissions than diesel during combustion, if enough methane is emitted across the fuel cycle, then switching a heavy-duty truck fleet from diesel to natural gas can produce net climate damages (more radiative forcing) for decades. Using the Technology Warming Potential methodology, we assess the climate implications of a diesel to natural gas switch in heavy-duty trucks. We consider spark ignition (SI) and high-pressure direct injection (HPDI) natural gas engines and compressed and liquefied natural gas. Given uncertainty surrounding several key assumptions and the potential for technology to evolve, results are evaluated for a range of inputs for well-to-pump natural gas loss rates, vehicle efficiency, and pump-to-wheels (in-use) methane emissions. Using reference case assumptions reflecting currently available data, we find that converting heavy-duty truck fleets leads to damages to the climate for several decades: around 70-90 years for the SI cases, and 50 years for the more efficient HPDI. Our range of results indicates that these fuel switches have the potential to produce climate benefits on all time frames, but combinations of significant well-to-wheels methane emissions reductions and natural gas vehicle efficiency improvements would be required.

Utilization of waste cooking oil as an alternative fuel for Turkey.

PubMed

Arslan, Ridvan; Ulusoy, Yahya

2017-04-03

This study is based on three essential considerations concerning biodiesel obtained from waste cooking oil: diesel engine emissions of biodiesel produced from waste cooking oil, its potential in Turkey, and policies of the Turkish government about environmentally friendly alternative fuels. Emission tests have been realized with 35.8 kW, four-cylinder, four-stroke, direct injection diesel tractor engine. Test results are compared with Euro non-road emission standards for diesel fuel and five different blends of biodiesel production from waste cooking oil. The results of the experimental study show that the best blends are B10 and B20 as they show the lowest emission level. The other dimensions of the study include potential analysis of waste cooking oil as diesel fuels, referring to fuel price policies applied in the past, and proposed future policies about the same issues. It was also outlined some conclusions and recommendations in connection with recycling of waste oils as alternative fuels.

Catalytic transformations of biomass substrates using mixed metal oxides derived from substituted hydrotalcites

NASA Astrophysics Data System (ADS)

Macala, Gerald Stephen, II

Fueled by seemingly endless reserves of cheap and easily accessible fossil energy, the industrial age has brought to the developed world tremendous advances in human health and well being. Unfortunately the burning of fossil fuels has also been implicated in increasing atmospheric CO2 concentrations and global climate change. Concerns about short-term and long-term supply further build a case for the need for alternative energy sources. Biomass derived materials are a tantalizing source of fuels and fine chemicals. Unlike petroleum derived hydrocarbons, biomass can be both renewable and carbon neutral. Crops can be regenerated annually or even more often in tropical climates, and since the captured carbon originates as atmospheric CO2, the overall cycle has the potential to be nearly carbon neutral regardless of the final fate of the carbon. In contrast to petroleum derived hydrocarbons, which can often be made more valuable by adding functionality, biomass derived materials are already highly functionalized and can usually be made more valuable by selective removal of functionality. The development of robust catalysts capable of selective defuntionalization of biomass derived substrates remains an important challenge with potentially enormous economic and societal impact. In addition to being robust and selective, catalysts should preferably be heterogeneous to allow for easier removal and regeneration after the reaction is complete. New materials consisting of Mg-Al hydrotalcite-like structures, with a limiting percentage of Mg or Al substituted with other M2+ or M3+ cations, were synthesized by a co-precipitation process in basic aqueous solution with carbonate as counterion. Calcination of these materials at 460 °C resulted in evolution of CO2 and water and yielded high surface area mixed metal oxides with enhanced reactivity. Materials were characterized by ICP for elemental analysis, XRD for structural information, XPS for surface elemental analysis and TEM for morphology. Substituting some of the Al for ferric ion resulted in enhanced basicity and enhanced reactivity towards transesterification of seed oil and the model compound triacetin. Substituting some of the Mg for cupric ion resulted in a transfer hydrogenation catalyst capable of single pot dehydrogenation of methanol and hydrogenation of the model compound dihydrobenzofuran.

Safeguards Considerations for Thorium Fuel Cycles

DOE PAGES

Worrall, Louise G.; Worrall, Andrew; Flanagan, George F.; ...

2016-04-21

We report that by around 2025, thorium-based fuel cycles are likely to be deployed internationally. States such as China and India are pursuing research, development, and deployment pathways toward a number of commercial-scale thorium fuel cycles, and they are already building test reactors and the associated fuel cycle infrastructure. In the future, the potential exists for these emerging programs to sell, export, and deploy thorium fuel cycle technology in other states. Without technically adequate international safeguards protocols and measures in place, any future potential clandestine misuse of these fuel cycles could go undetected, compromising the deterrent value of these protocolsmore » and measures. The development of safeguards approaches for thorium-based fuel cycles is therefore a matter of some urgency. Yet, the focus of the international safeguards community remains mainly on safeguarding conventional 235U- and 239Pu-based fuel cycles while the safeguards challenges of thorium-uranium fuel cycles remain largely uninvestigated. This raises the following question: Is the International Atomic Energy Agency and international safeguards system ready for thorium fuel cycles? Furthermore, is the safeguards technology of today sufficiently mature to meet the verification challenges posed by thorium-based fuel cycles? In defining these and other related research questions, the objectives of this paper are to identify key safeguards considerations for thorium-based fuel cycles and to call for an early dialogue between the international safeguards and the nuclear fuel cycle communities to prepare for the potential safeguards challenges associated with these fuel cycles. In this paper, it is concluded that directed research and development programs are required to meet the identified safeguards challenges and to take timely action in preparation for the international deployment of thorium fuel cycles.« less

The genus Shewanella: from the briny depths below to human pathogen.

PubMed

Janda, J Michael; Abbott, Sharon L

2014-11-01

The genus Shewanella is currently composed of more than 50 species that inhabit a range of marine environs and ecosystems. Several members of this genus, including S. oneidensis, have been identified that could potentially play key roles in environmental processes such as bioremediation of toxic elements and heavy metals and serving as microbial fuel cells. In contrast to this beneficial role, shewanellae are increasingly being implicated as human pathogens in persons exposed through occupational or recreational activities to marine niches containing shewanellae. Documented illnesses linked to Shewanella include skin and soft tissue infections, bacteremia, and otitis media. At present, it is unclear exactly how many Shewanella species are truly bona fide human pathogens. Recent advances in the taxonomy and phylogenetic relatedness of members of this genus, however, support the concept that most human infections are caused by a single species, S. algae. Some phylogenetic data further suggest that some current members of the genus are not true Shewanella species sensu stricto. The current review summarizes our present knowledge of the distribution, epidemiology, disease spectrum, and identification of microbial species focusing on a clinical perspective.

Optimising boiler performance.

PubMed

Mayoh, Paul

2009-01-01

Soaring fuel costs continue to put the squeeze on already tight health service budgets. Yet it is estimated that combining established good practice with improved technologies could save between 10% and 30% of fuel costs for boilers. Paul Mayoh, UK technical manager at Spirax Sarco, examines some of the practical measures that healthcare organisations can take to gain their share of these potential savings.

Chemical composition of gas-phase organic carbon emissions from motor vehicles and implications for ozone production.

PubMed

Gentner, Drew R; Worton, David R; Isaacman, Gabriel; Davis, Laura C; Dallmann, Timothy R; Wood, Ezra C; Herndon, Scott C; Goldstein, Allen H; Harley, Robert A

2013-10-15

Motor vehicles are major sources of gas-phase organic carbon, which includes volatile organic compounds (VOCs) and other compounds with lower vapor pressures. These emissions react in the atmosphere, leading to the formation of ozone and secondary organic aerosol (SOA). With more chemical detail than previous studies, we report emission factors for over 230 compounds from gasoline and diesel vehicles via two methods. First we use speciated measurements of exhaust emissions from on-road vehicles in summer 2010. Second, we use a fuel composition-based approach to quantify uncombusted fuel components in exhaust using the emission factor for total uncombusted fuel in exhaust together with detailed chemical characterization of liquid fuel samples. There is good agreement between the two methods except for products of incomplete combustion, which are not present in uncombusted fuels and comprise 32 ± 2% of gasoline exhaust and 26 ± 1% of diesel exhaust by mass. We calculate and compare ozone production potentials of diesel exhaust, gasoline exhaust, and nontailpipe gasoline emissions. Per mass emitted, the gas-phase organic compounds in gasoline exhaust have the largest potential impact on ozone production with over half of the ozone formation due to products of incomplete combustion (e.g., alkenes and oxygenated VOCs). When combined with data on gasoline and diesel fuel sales in the U.S., these results indicate that gasoline sources are responsible for 69-96% of emissions and 79-97% of the ozone formation potential from gas-phase organic carbon emitted by motor vehicles.

Obesity Paradox in Lung Cancer Prognosis: Evolving Biological Insights and Clinical Implications.

PubMed

Zhang, Xueli; Liu, Yamin; Shao, Hua; Zheng, Xiao

2017-10-01

The survival rate of lung cancer remains low despite the progress of surgery and chemotherapy. With the increasing comorbidity of obesity in patients with lung cancer, new challenges are emerging in the management of this patient population. A key issue of interest is the prognostic effect of obesity on surgical and chemotherapeutic outcomes in patients with lung cancer, which is fueled by the growing observation of survival benefits in overweight or obese patients. This unexpected inverse relationship between obesity and lung cancer mortality, called the obesity paradox, remains poorly understood. The evolving insights into the heterogeneity of obesity phenotypes and associated biological connections with lung cancer progression in recent years may help explain some of the seemingly paradoxical relationship, and well-designed clinical studies looking at the causal role of obesity-associated molecules are expected. Here, we examine potential biological mechanisms behind the protective effects of obesity in lung cancer. We highlight the need to clarify the clinical implications of this relationship toward an updated intervention strategy in the clinical care of patients with lung cancer and obesity. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

Examining land use change and cooking fuel-use in Uganda: implications and potential win-win scenarios for policy and carbon financing

NASA Astrophysics Data System (ADS)

Brunner, Nicole; Semmens, Darius; Hawbaker, Todd

2016-04-01

Uganda is one of the world's most biodiverse countries, yet also one of the poorest. Human dependence on natural resources, especially from forests, is most pronounced in developing countries such as Uganda, where many people live in poverty and rely on fuel wood for cooking. These demands often compete with conservation efforts aimed at protecting forests and biodiversity. An understanding of trends in forest condition and local community use of forests is necessary to explore the implications of changing environmental conditions on the sustainability of Uganda's forests and forest-related socioeconomic activities. A human-environment framework is applied to this research by comparing environmental layers derived from remotely sensed imagery with socioeconomic data acquired from household surveys. Statistical modeling was used to explain the relationship between household characteristics (e.g., fuel use) and environmental characteristics (e.g., land cover change) and to quantify the role of spatial arrangement or pattern in understanding human-environment relationships (e.g., access and distance). The findings show that distance from protected forests is related to changes in household fuel type. For example, increases in charcoal as the primary cooking fuel is observed in households a closer distance to protected forests. This change is likely due to access to forest resources. The results of this study could inform policies aimed at protecting forests as well as protecting the interests of people in proximity to protected forests.

The origin of organic pollutants from the combustion of alternative fuels: Phase IV report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, P.H.; Dellinger, B.; Sidhu, S.K.

As part of the US-DOE`s on-going interest in the use of alternative automotive fuels, the University of Dayton Research Institute has been conducting research on pollutant emissions resulting from the combustion of candidate fuels. This research, under the direction and sponsorship of the NREL, has been concerned primarily with the combustion of compressed natural gas, liquefied petroleum gas (LPG), methanol, and ethanol. In the first 24 months of this program, studies of the oxygen rich, stoichiometric, and fuel-rich thermal degradation of these fuels in the temperature range of 300 to 1100{degrees}C at atmospheric pressure and for reaction times of 1.0more » and 2.0 s were completed. Trace organic products were identified and quantified for each fuel as a function of temperature. The results of these studies agreed well with the results of tail-pipe emission studies in that the types and quantity of emissions measured in both the laboratory and engine tests were shown to be very similar under certain operating conditions. However, some chemicals were observed in the laboratory studies that were not observed in the engine studies and vice versa. This result is important in that it has implications concerning the origin of these emissions. Experiments concerning the NO perturbed oxidation of methanol, M85, ethanol, and E85 indicated the presence of complex oxidation chemistry. At mild temperatures, NO addition resulted in enhanced fuel conversion. At elevated temperatures, an inhibitory effect was observed through increased yields of both partial oxidation and pyrolysis-type reaction products. Comparison of flow reactor product distributions with engine test results generally indicated improved comparisons when NO was added to the fuel. Analysis of secondary components of alcohol fuels resulted in some unexpected observations. Several previously unidentified species were observed in these experiments which may impact atmospheric reactivity assessments of these fuels.« less

Evaluation of chosen fruit seeds oils as potential biofuel

NASA Astrophysics Data System (ADS)

Agbede, O. O.; Alade, A. O.; Adebayo, G. A.; Salam, K. K.; Bakare, T.

2012-04-01

Oils available in mango, tangerine and African star seeds were extracted and characterized to determine their fuel worthiness for biofuel production. Furthermore, the fuel properties of the three oils were within the range observed for some common oil seeds like rapeseed, soybean and sunflower, which are widely sourced for the production of biodiesel on an industrial scale. The low iodine values of the oil extend their applications as non-drying oil for lubrication purposes, however, the fuel properties exhibited by the oils enlist them as potential oil seeds for the production of biofuel and further research on the improvement of their properties will make them suitable biofuel of high economic values.

Polymer electrolyte fuel cells for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, T.E.; Wilson, M.S.; Garzon, F.H.

1993-01-01

The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received incrming attention during the last few years. This increased attention has been fueled by a combination of significant technical advances in this field and by the initiation of some projects for the demonstration of a complete, PEFC-based power system in a bus or in a passenger car. Such demonstration pretieds reflect an increased faith of industry in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential Nevertheless, large scalemore » transportation applications of PEFCs requim a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve cost effective, highly performing PEFC stack and power system. We describe in this contribution some recent results of work performed within the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed transportation applications of PEFCs.« less

Polymer electrolyte fuel cells for transportation applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, T.E.; Wilson, M.S.; Garzon, F.H.

1993-03-01

The application of the polymer electrolyte fuel cell (PEFC) as a primary power source in electric vehicles has received incrming attention during the last few years. This increased attention has been fueled by a combination of significant technical advances in this field and by the initiation of some projects for the demonstration of a complete, PEFC-based power system in a bus or in a passenger car. Such demonstration pretieds reflect an increased faith of industry in the potential of this technology for transportation applications, or, at least, in the need for a detailed evaluation of this potential Nevertheless, large scalemore » transportation applications of PEFCs requim a continued concerted effort of research on catalysis, materials and components, combined with the engineering efforts addressing the complete power system. This is required to achieve cost effective, highly performing PEFC stack and power system. We describe in this contribution some recent results of work performed within the Core Research PEFC Program at Los Alamos National Laboratory, which has addressed transportation applications of PEFCs.« less

Chapter 11 - Post-hurricane fuel dynamics and implications for fire behavior (Project SO-EM-F-12-01)

Treesearch

Shanyue Guan; G. Geoff. Wang

2018-01-01

Hurricanes have long been a powerful and recurring disturbance in many coastal forest ecosystems. Intense hurricanes often produce a large amount of dead fuels in their affected forests. How the post-hurricane fuel complex changes with time, due todecomposition and management such as salvage, and its implications for fire behavior remain largely unknown....

Causes and Mitigation of Fuel Pilot Operated Valve Pilot Seal Extrusion in Space Shuttle Orbiter Primary RCS Thrusters

NASA Technical Reports Server (NTRS)

Waller, Jess M.; Roth, Tim E.; Saulsberry, Regor L.; Haney, William A.; Kelly, Terence S; Forsyth, Bradley S.

2004-01-01

Extrusion of a polytetrafluoroethylene (PTFE) pilot seal located in the Space Shuttle Orbiter Primary Reaction Control Subsystem (PRCS) thruster fuel valve has been implicated in 68 ground and on-orbit fuel valve failures. A rash of six extrusion-related in-flight anomalies over a six-mission span from December 2001 to October 2002 led to heightened activity at various NASA centers, and the formation of a multidisciplinary team to solve the problem. Empirical and theoretical approaches were used. For example, thermomechanical analysis (TMA) and exposure tests showed that some extrusion is produced by thermal cycling; however, a review of thruster service histories did not reveal a strong link between thermal cycling and extrusion. Calculations showed that the amount of observed extrusion often exceeded the amount allowed by thermally-induced stress relief. Failure analysis of failed hardware also revealed the presence of fuel-oxidizer reaction product (FORP) inside the fuel valve pilot seal cavity, and differential scanning calorimetry (DSC) showed that the FORP was intimately associated with the pilot seal material. Component-level exposure tests showed that FORP of similar composition could be produced by adjacent oxidizer valve leakage in the absence of thruster firing. Specific gravity data showed that extruded fuel valve pilot seals were less dense than new pilot seals or oxidizer valve pilot seals, indicating permanent modification of the PTFE occurred during service. It is concluded that some thermally-induced extrusion is unavoidable; however, oxidizer leakage-induced extrusion is mostly avoidable and can be mitigated. Several engineering level mitigation strategies are discussed.

Fuels and chemicals from biomass using solar thermal energy

NASA Technical Reports Server (NTRS)

Giori, G.; Leitheiser, R.; Wayman, M.

1981-01-01

The significant nearer term opportunities for the application of solar thermal energy to the manufacture of fuels and chemicals from biomass are summarized, with some comments on resource availability, market potential and economics. Consideration is given to the production of furfural from agricultural residues, and the role of furfural and its derivatives as a replacement for petrochemicals in the plastics industry.

Effects of bark beetle attack on canopy fuel flammability and crown fire potential in lodgepole pine and Engelmann spruce forests

Treesearch

Wesley G. Page; Martin E. Alexander; Michael J. Jenkins

2015-01-01

Large wildland fires in conifer forests typically involve some degree of crowning, with their initiation and propagation dependent upon several characteristics of the canopy fuels. Recent outbreaks of mountain pine beetle (Dendroctonus ponderosae Hopkins) in lodgepole pine (Pinus contorta Dougl. var. latifolia E ngelm.) forests and spruce beetle (Dendroctonus...

Ototoxic potential of JP-8 and a Fischer-Tropsch synthetic jet fuel following subacute inhalation exposure in rats.

PubMed

Fechter, Laurence D; Gearhart, Caroline A; Fulton, Sherry

2010-07-01

This study was undertaken to identify the ototoxic potential of two jet fuels presented alone and in combination with noise. Rats were exposed via a subacute inhalation paradigm to JP-8 jet fuel, a kerosene-based fuel refined from petroleum, and a synthetic fuel produced by the Fischer-Tropsch (FT) process. Although JP-8 contains small ( approximately 5%) concentrations of aromatic hydrocarbons some of which known to be ototoxic, the synthetic fuel does not. The objectives of this study were to identify a lowest observed adverse effect level and a no observed adverse effect level for each jet fuel and to provide some preliminary, but admittedly, indirect evidence concerning the possible role of the aromatic hydrocarbon component of petroleum-based jet fuel on hearing. Rats (n = 5-19) received inhalation exposure to JP-8 or to FT fuel for 4 h/day on five consecutive days at doses of 500, 1000, and 2000 mg/m(3). Additional groups were exposed to various fuel concentrations followed by 1 h of an octave band of noise, noise alone, or no exposure to fuel or noise. Significant dose-related impairment in the distortion product otoacoustic emissions (DPOAE) was seen in subjects exposed to combined JP-8 plus noise exposure when JP-8 levels of at least 1000 mg/m(3) were presented. No noticeable impairment was observed at JP-8 levels of 500 mg/m(3) + noise. In contrast to the effects of JP-8 on noise-induced hearing loss, FT exposure had no effect by itself or in combination with noise exposure even at the highest exposure level tested. Despite an observed loss in DPOAE amplitude seen only when JP-8 and noise were combined, there was no loss in auditory threshold or increase in hair cell loss in any exposure group.

Synthetic and Biomass Alternate Fueling in Aviation

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Bushnell, D. M.

2009-01-01

While transportation fueling can accommodate a broad range of alternate fuels, aviation fueling needs are specific, such as the fuel not freezing at altitude or become too viscous to flow properly or of low bulk energy density that shortens range. The fuel must also be compatible with legacy aircraft, some of which are more than 50 years old. Worldwide, the aviation industry alone uses some 85-95 billion gallons of hydrocarbon-based fossil fuel each year, which is about 10% of the transportation industry. US civil aviation alone consumes nearly 14 billion gallons. The enormity of the problem becomes overwhelming, and the aviation industry is taking alternate fueling issues very seriously. Biofuels (algae, cyanobacteria, halophytes, weeds that use wastelands, wastewater and seatwater), when properly sourced, have the capacity to be drop-in fuel replacements for petroleum fuels. As such, biojet from such sources solves the aviation CO2 emissions issue without the downsides of 'conventional' biofuels, such as competing with food and fresh water resources. Of the many current fundamental problems, the major biofuel problem is cost. Both research and development and creative engineering are required to reduce these biofuels costs. Research is also ongoing in several 'improvement' areas including refining/processing and biologics with greater disease resistance, greater bio-oil productivity, reduced water/nutrient requirements, etc. The authors' current research is aimed at aiding industry efforts in several areas. They are considering different modeling approaches, growth media and refining approaches, different biologic feedstocks, methods of sequestering carbon in the processes, fuel certification for aviation use and, overall, ensuring that biofuels are feasible from all aspects - operability, capacity, carbon cycle and financial. The authors are also providing common discussion grounds/opportunities for the various parties, disciplines and concerned organization to share both issues and potential ways for moving forward, and overall, trying to educate those concerned about the innate limitations of 'conventional' biofuels and the solutions provided by non-traditional feedstocks that used waste lands/water or saline/salt water have an immense capacity potential.

Continental-scale enrichment of atmospheric 14CO2 from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO2

NASA Astrophysics Data System (ADS)

Graven, H. D.; Gruber, N.

2011-12-01

The 14C-free fossil carbon added to atmospheric CO2 by combustion dilutes the atmospheric 14C/C ratio (Δ14C), potentially providing a means to verify fossil CO2 emissions calculated using economic inventories. However, sources of 14C from nuclear power generation and spent fuel reprocessing can counteract this dilution and may bias 14C/C-based estimates of fossil fuel-derived CO2 if these nuclear influences are not correctly accounted for. Previous studies have examined nuclear influences on local scales, but the potential for continental-scale influences on Δ14C has not yet been explored. We estimate annual 14C emissions from each nuclear site in the world and conduct an Eulerian transport modeling study to investigate the continental-scale, steady-state gradients of Δ14C caused by nuclear activities and fossil fuel combustion. Over large regions of Europe, North America and East Asia, nuclear enrichment may offset at least 20% of the fossil fuel dilution in Δ14C, corresponding to potential biases of more than -0.25 ppm in the CO2 attributed to fossil fuel emissions, larger than the bias from plant and soil respiration in some areas. Model grid cells including high 14C-release reactors or fuel reprocessing sites showed much larger nuclear enrichment, despite the coarse model resolution of 1.8°×1.8°. The recent growth of nuclear 14C emissions increased the potential nuclear bias over 1985-2005, suggesting that changing nuclear activities may complicate the use of Δ14C observations to identify trends in fossil fuel emissions. The magnitude of the potential nuclear bias is largely independent of the choice of reference station in the context of continental-scale Eulerian transport and inversion studies, but could potentially be reduced by an appropriate choice of reference station in the context of local-scale assessments.

Housing and respiratory health at older ages.

PubMed

Webb, E; Blane, D; de Vries, Robert

2013-03-01

A large proportion of the population of England live in substandard housing. Previous research has suggested that poor-quality housing, particularly in terms of cold temperatures, mould, and damp, poses a health risk, particularly for older people. The present study aimed to examine the association between housing conditions and objectively measured respiratory health in a large general population sample of older people in England. Data on housing conditions, respiratory health and relevant covariates were obtained from the second wave of the English Longitudinal Study of Ageing. Multivariate regression methods were used to test the association between contemporary housing conditions and respiratory health while accounting for the potential effect of other factors; including social class, previous life-course housing conditions and childhood respiratory health. Older people who were in fuel poverty or who did not live in a home they owned had significantly worse respiratory health as measured by peak expiratory flow rates. After accounting for covariates, these factors had no effect on any other measures of respiratory health. Self-reported housing problems were not consistently associated with respiratory health. The housing conditions of older people in England, particularly those associated with fuel poverty and living in rented accommodation, may be harmful to some aspects of respiratory health. This has implications for upcoming UK government housing and energy policy decisions.

Scenarios for Low Carbon and Low Water Electric Power Plant Operations: Implications for Upstream Water Use.

PubMed

Dodder, Rebecca S; Barnwell, Jessica T; Yelverton, William H

2016-11-01

Electric sector water use, in particular for thermoelectric operations, is a critical component of the water-energy nexus. On a life cycle basis per unit of electricity generated, operational (e.g., cooling system) water use is substantially higher than water demands for the fuel cycle (e.g., natural gas and coal) and power plant manufacturing (e.g., equipment and construction). However, could shifting toward low carbon and low water electric power operations create trade-offs across the electricity life cycle? We compare business-as-usual with scenarios of carbon reductions and water constraints using the MARKet ALlocation (MARKAL) energy system model. Our scenarios show that, for water withdrawals, the trade-offs are minimal: operational water use accounts for over 95% of life cycle withdrawals. For water consumption, however, this analysis identifies potential trade-offs under some scenarios. Nationally, water use for the fuel cycle and power plant manufacturing can reach up to 26% of the total life cycle consumption. In the western United States, nonoperational consumption can even exceed operational demands. In particular, water use for biomass feedstock irrigation and manufacturing/construction of solar power facilities could increase with high deployment. As the United States moves toward lower carbon electric power operations, consideration of shifting water demands can help avoid unintended consequences.

Baseline measurements of ethene in 2002: Implications for increased ethanol use and biomass burning on air quality and ecosystems

NASA Astrophysics Data System (ADS)

Gaffney, Jeffrey S.; Marley, Nancy A.; Blake, Donald R.

2012-09-01

While it is well known that combustion of ethanol as a biofuel will lead to enhanced emissions of methane, ethene (ethylene), acetaldehyde, formaldehyde, and oxides of nitrogen (primarily NO) when compared to gasoline alone, especially during cold starts or if catalytic converters are not operating properly, the impacts of increases in atmospheric ethene levels from combustion of fuels with higher ethanol content has not received much attention. Ethene is a well known and potent plant growth hormone and exposure to agricultural crops and natural vegetation results in yield reductions especially when combined with higher levels of PAN and ozone also expected from the increased use of ethanol/gasoline blends. We report here some baseline measurements of ethene obtained in 2002 in the southwestern and south central United States. These data indicate that current ethene background levels are less than 1 ppb. Anticipated increases in fuel ethanol content of E30 or greater is expected to lead to higher atmospheric levels of ethene on regional scales due to its atmospheric lifetime of 1.5-3 days. These background measurements are discussed in light of the potential enhancement of ethene levels expected from the anticipated increases in ethanol use as a renewable biofuel.

Biofuel alternatives to ethanol: pumping the microbial well

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortman, J. L.; Chhabra, Swapnil; Mukhopadhyay, Aindrila

Engineered microorganisms are currently used for the production of food products, pharmaceuticals, ethanol fuel and more. Even so, the enormous potential of this technology has yet to be fully exploited. The need for sustainable sources of transportation fuels has gener-ated a tremendous interest in technologies that enable biofuel production. Decades of work have produced a considerable knowledge-base for the physiology and pathway engineering of microbes, making microbial engineering an ideal strategy for producing biofuel. Although ethanol currently dominates the biofuel mar-ket, some of its inherent physical properties make it a less than ideal product. To highlight additional options, we reviewmore » advances in microbial engineering for the production of other potential fuel molecules, using a variety of biosynthetic pathways.« less

Biofuel alternatives to ethanol: pumping the microbial well

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortman, J.L.; Chhabra, Swapnil; Mukhopadhyay, Aindrila

2009-08-19

Engineered microorganisms are currently used for the production of food products, pharmaceuticals, ethanol fuel and more. Even so, the enormous potential of this technology has yet to be fully exploited. The need for sustainable sources of transportation fuels has generated a tremendous interest in technologies that enable biofuel production. Decades of work have produced a considerable knowledge-base for the physiology and pathway engineering of microbes, making microbial engineering an ideal strategy for producing biofuel. Although ethanol currently dominates the biofuel market, some of its inherent physical properties make it a less than ideal product. To highlight additional options, we reviewmore » advances in microbial engineering for the production of other potential fuel molecules, using a variety of biosynthetic pathways.« less

Alternative energy sources

NASA Astrophysics Data System (ADS)

Todd, R. W.

1982-04-01

Renewable energy sources and their potential contribution for solving energy needs are presented. Centralized supply technologies include those alternative fuels derived from biomass using solar energy, (supplying 57% of the energy supply in some countries), and those using directly collected solar energy to manufacture a fuel. Fuel utilization effects can be doubled by using combined heat and power stations, and other major sources include wind, wave, tidal, and solar. In terms of local supply technology, wood burning appliances are becoming more popular, and methane is being used for heating and to fuel spark ignition engines. Geothermal low temperature heating exists worldwide at a capacity of 7.2 GW, supplying heat, particularly in Hungary, parts of the U.S.S.R., and Iceland, and a geothermal research program has been established in the United States. Sweden has a potential hydroelectric capacity of 600 MW, and the United States has a 100 GW capacity. Many of these technologies are already cost effective.

Automobiles and global warming: Alternative fuels and other options for carbon dioxide emissions reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagar, A.D.

Automobiles are a source of considerable pollution at the global level, including a significant fraction of the total greenhouse gas emissions. Alternative fuels have received some attention as potential options to curtail the carbon dioxide emissions from motor vehicles. This article discusses the feasibility and desirability (from a technical as well as a broader environmental perspective) of the large-scale production and use of alternative fuels as a strategy to mitigate automotive carbon dioxide emissions. Other options such as improving vehicle efficiency and switching to more efficient modes of passenger transportation are also discussed. These latter options offer an effective andmore » immediate way to tackle the greenhouse and other pollutant emission from automobiles, especially as the limitations of currently available alternative fuels and the technological and other constraints for potential future alternatives are revealed.« less

The potential pyrophoricity of BMI-SPEC and aluminum plate spent fuels retrieved from underwater storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebner, M.A.

1996-08-01

Physical/chemical factors in U metal and hydride combustion, particularly pyrophoricity in ambient environment, were evaluated for BMI-SPEC and UAl{sub x} plate fuels. Some metal fuels may be highly reactive (spontaneously igniting in air) due to high specific surface area, high decay heat, or a high U hydride content from corrosion during underwater storage. However, for the BMI-SPEC and the aluminum plate fuels, this reactivity is too low to present a realistic threat of uncontrolled spontaneous combustion at ambient conditions. While residual U hydride is expected in these corroded fuels, the hydride levels are expected to be too low and themore » configuration too unfavorable to ignite the fuel meat when the fuels are retrieved from the basin and dried. Furthermore the composition and microstructure of the UAl{sub x} fuels further mitigate that risk.« less

Candida keroseneae sp. nov., a novel contaminant of aviation kerosene.

PubMed

Buddie, A G; Bridge, P D; Kelley, J; Ryan, M J

2011-01-01

To characterize and identify a novel contaminant of aviation fuel. Micro-organisms (yeasts and bacteria) were isolated from samples of aviation fuel. A yeast that proved to have been unrecorded previously was isolated from more than one fuel sample. This novel yeast proved to be a new species of Candida and is described here. Ribosomal RNA gene sequence analyses of internal transcribed spacer (ITS) regions (including 5·8S subunit) plus the 26S D1/D2 domains showed the strains to cluster within the Candida membranifaciens clade nearest to, but distinct from, Candida tumulicola. Phenotypic tests were identical for both isolates. Physiological and biochemical tests supported their position as a separate taxon. The yeast was assessed for its effect on the main constituent hydrocarbons of aviation fuel. Two strains (IMI 395605(T) and IMI 395606) belonging to the novel yeast species, Candida keroseneae, were isolated from samples of aircraft fuel (kerosene), characterized and described herein with reference to their potential as contaminants of aviation fuel. As a result of isolating a novel yeast from aviation fuel, the implications for microbial contamination of such fuel should be considered more widely than previously thought. © 2010 CAB International. Letters in Applied Microbiology © 2010 The Society for Applied Microbiology.

Rating hydrogen as a potential aviation fuel

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1980-01-01

The viability of liquid hydrogen, liquid methane, and synthetic aviation kerosene as future alternate fuels for transport aircraft is analyzed, and the results of a comparative assessment are given in terms of cost, energy resource utilization, areas of fuel production, transmission airport facilities, and ultimate use in the aircraft. Important safety (fires) and some environmental aspects (CO2 balance) are also described. It is concluded that fuel price estimates indicate the price of synthetic aviation kerosene (synjet) would be approximately half of the price calculated for liquid hydrogen and somewhat less than that of liquid methane, with synjet from oil shale reported to be the least expensive.

Methane Hydrates: More Than a Viable Aviation Fuel Feedstock Option

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.

2007-01-01

Demand for hydrocarbon fuels is steadily increasing, and greenhouse gas emissions continue to rise unabated with the energy demand. Alternate fuels will be coming on line to meet that demand. This report examines the recovering of methane from methane hydrates for fuel to meet this demand rather than permitting its natural release into the environment, which will be detrimental to the planet. Some background on the nature, vast sizes, and stability of sedimentary and permafrost formations of hydrates are discussed. A few examples of the severe problems associated with methane recovery from these hydrates are presented along with the potential impact on the environment and coastal waters. Future availability of methane from hydrates may become an attractive option for aviation fueling, and so future aircraft design associated with methane fueling is considered.

A Shift in the International Security Environment: Potential Implications for Defense - Issues for Congress

DTIC Science & Technology

2016-06-08

Affairs June 8, 2016 Congressional Research Service 7-5700 www.crs.gov R43838 A Shift in the International Security Environment: Potential...Implications for Defense Congressional Research Service Summary World events have led some observers, starting in late 2013, to conclude that the...Defense Congressional Research Service Contents Introduction

Professional Advanced Research and Analysis

NASA Technical Reports Server (NTRS)

Coulman, George A.

1996-01-01

Reported here is a summary of studies examining some problems in an energy conversion system. Regenerative fuel cell systems have been suggested for future manned space missions, but to meet the needed specific power requirements substantial improvements in the state-of-the-art technologies are needed. Similar improvements are needed, with emphasis on cost reduction in addition to higher conversion efficiency, for fuel cell systems that have potential for terrestrial applications. Polymer Electrolyte Membrane (PEM) fuel cells have been identified as promising candidates for development that would lead to the desired cost reduction and increased efficiency.

The British Nuclear Deterrent After the Cold War,

DTIC Science & Technology

1995-01-01

Scope for Further Franco-British Cooperation 86 Attitudes of Friends and Allies 9° 7 . SOME POLICY IMPLICATIONS 94 A " Blessing in Disguise" for...on French decision, and French decision alone." 94 SOME POLICY IMPLICATIONS A " BLESSING IN DISGUISE" FOR EUROPEAN SECURITY It is time to take...but those disposing of any form of "weapon of mass i:LVictor A. Utgoff, "The Biotechnology Revolution and Its Potential Military Implications ," in

Potential of global croplands and bioenergy crops for climate change mitigation through deployment for enhanced weathering.

PubMed

Kantola, Ilsa B; Masters, Michael D; Beerling, David J; Long, Stephen P; DeLucia, Evan H

2017-04-01

Conventional row crop agriculture for both food and fuel is a source of carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) to the atmosphere, and intensifying production on agricultural land increases the potential for soil C loss and soil acidification due to fertilizer use. Enhanced weathering (EW) in agricultural soils-applying crushed silicate rock as a soil amendment-is a method for combating global climate change while increasing nutrient availability to plants. EW uses land that is already producing food and fuel to sequester carbon (C), and reduces N 2 O loss through pH buffering. As biofuel use increases, EW in bioenergy crops offers the opportunity to sequester CO 2 while reducing fossil fuel combustion. Uncertainties remain in the long-term effects and global implications of large-scale efforts to directly manipulate Earth's atmospheric CO 2 composition, but EW in agricultural lands is an opportunity to employ these soils to sequester atmospheric C while benefitting crop production and the global climate. © 2017 The Author(s).

Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival

USGS Publications Warehouse

Collins, Brandon M.; Das, Adrian J.; Battles, John J.; Fry, Danny L.; Krasnow, Kevin D.; Stephens, Scott L.

2014-01-01

Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively depending on the specific elements examined, as well as treatment type, timing, and intensity. In this study, we use overstory tree growth responses, measured seven years after the most common fuel treatments, to estimate forest health. Across the five species analyzed, observed mortality and future vulnerability were consistently low in the mechanical-only treatment. Fire-only was similar to the control for all species except Douglas-fir, while mechanical-plus-fire had high observed mortality and future vulnerability for white fir and sugar pine. Given that overstory trees largely dictate the function of forests and services they provide (e.g., wildlife habitat, carbon sequestration, soil stability) these results have implications for understanding longer-term impacts of common fuel treatments on forest resilience.

Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival.

PubMed

Collins, Brandon M; Das, Adrian J; Battles, John J; Fry, Danny L; Krasnow, Kevin D; Stephens, Scott L

Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively depending on the specific elements examined, as well as treatment type, timing, and intensity. In this study, we use overstory tree growth responses, measured seven years after the most common fuel treatments, to estimate forest health. Across the five species analyzed, observed mortality and future vulnerability were consistently low in the mechanical- only treatment. Fire-only was similar to the control for all species except Douglas-fir, while mechanical-plus-fire had high observed mortality and future vulnerability for white fir and sugar pine. Given that overstory trees largely dictate the function of forests and services they provide (e.g., wildlife habitat, carbon sequestration, soil stability) these results have implications for understanding longer-term impacts of common fuel treatments on forest resilience.

Reducing residential solid fuel combustion through electrified space heating leads to substantial air quality, health and climate benefits in China's Beijing-Tianjin-Hebei region

NASA Astrophysics Data System (ADS)

Yang, J.; Mauzerall, D. L.

2017-12-01

During periods of high pollution in winter, household space heating can contribute more than half of PM2.5 concentrations in China's Beijing-Tianjin-Hebei (BTH) region. The majority of rural households and some urban households in the region still heat with small stoves and solid fuels such as raw coal, coal briquettes and biomass. Thus, reducing emissions from residential space heating has become a top priority of the Chinese government's air pollution mitigation plan. Electrified space heating is a promising alternative to solid fuel. However, there is little analysis of the air quality and climate implications of choosing various electrified heating devices and utilizing different electricity sources. Here we conduct an integrated assessment of the air quality, human health and climate implications of various electrified heating scenarios in the BTH region using the Weather Research and Forecasting model with Chemistry. We use the Multi-resolution Emission Inventory for China for the year 2012 as our base case and design two electrification scenarios in which either direct resistance heaters or air source heat pumps are installed to replace all household heating stoves. We initially assume all electrified heating devices use electricity from supercritical coal-fired power plants. We find that installing air source heat pumps reduces CO2 emissions and premature deaths due to PM2.5 pollution more than resistance heaters, relative to the base case. The increased health and climate benefits of heat pumps occur because they have a higher heat conversion efficiency and thus require less electricity for space heating than resistance heaters. We also find that with the same heat pump installation, a hybrid electricity source (40% of the electricity generated from renewable sources and the rest from coal) further reduces both CO2 emissions and premature deaths than using electricity only from coal. Our study demonstrates the air pollution and CO2 mitigation potential and public health benefits of using electrified space heating. In particular, we find air source heat pumps could bring more climate and health benefits than direct resistance heaters. Our results also support policies to integrate renewable energy sources with the reduction of solid fuel combustion for residential space heating.

Constraints on gene patent protection fuel secrecy concerns: a qualitative study

PubMed Central

Guerrini, Christi J; McGuire, Amy L; Majumder, Mary A; Bollinger, Juli M; Rowan, Paul J

2017-01-01

Abstract Concern is mounting that innovators are responding to recent changes in patent eligibility by increasingly choosing to protect their discoveries as trade secrets. Due to the clandestine nature of trade secrets, it is impossible to quantify the extent to which innovators actually elect to protect their inventions as trade secrets rather than patents. Nevertheless, interest in each strategy may be gauged through qualitative means. We conducted semi-structured interviews of legal and scientific experts (n = 30) to understand the effect of recent patent eligibility changes on interest in patenting and trade secrecy of genetic innovations. Interview data indicate that secrecy may have increased in strategic appeal relative to patent protection in some areas of genetic innovation, although the actual election of secrecy strategies is often limited as a practical matter. The data also suggest that the burden of navigating the new intellectual property landscape may be falling disproportionately on those who translate gene-based discoveries into clinical applications. Some interviewees expressed concern about the normative implications of secrecy on advancements in and access to genetic medicine. Our findings are potentially relevant to policy proposals intended to restore some of the legal protection that was lost as a result of recent changes to patent eligibility, including amending the federal patent statute and expanding regulatory exclusivities for some genetic technologies. PMID:29868184

Greenland Inland Traverse (GrIT): 2010 Mobility Performance and Implications

DTIC Science & Technology

2011-10-01

solar irradiance were also measured. The right-hand bladder sled (Fig. 5), designated Sled2, had black- rubber covers ( EPDM roofing material) wrapped...CRREL TR-11-16 ix tion only). Sled2 had thin, black- rubber covers over the bladders to in- crease solar gain. Some performance improvement...Pole Station from McMurdo Station, a distance of 1030 miles, using large, rubber -track tractors to haul fuel and cargo over the snow on flexible

The Defense Acquisition Workforce Growth Initiative: Changing Workforce Characteristics and the Implications for Workforce Retention

DTIC Science & Technology

2017-01-01

entrants’ prior work experience . This dissertation utilizes DoD personnel data to (1) describe civilian DAW cohorts in terms of past work experience and...illustrate how the hiring surge has changed cohort past-work- experience characteristics; (2) evaluate how prior work experience relates to retention...growth initiative was fueled mainly by outside hires with no prior DoD experience , and some evidence suggests that these DoD newcomers—in general

Impact of fuel quality regulation and speed reductions on shipping emissions: implications for climate and air quality.

PubMed

Lack, Daniel A; Cappa, Christopher D; Langridge, Justin; Bahreini, Roya; Buffaloe, Gina; Brock, Charles; Cerully, Kate; Coffman, Derek; Hayden, Katherine; Holloway, John; Lerner, Brian; Massoli, Paola; Li, Shao-Meng; McLaren, Robert; Middlebrook, Ann M; Moore, Richard; Nenes, Athanasios; Nuaaman, Ibraheem; Onasch, Timothy B; Peischl, Jeff; Perring, Anne; Quinn, Patricia K; Ryerson, Tom; Schwartz, Joshua P; Spackman, Ryan; Wofsy, Steven C; Worsnop, Doug; Xiang, Bin; Williams, Eric

2011-10-15

Atmospheric emissions of gas and particulate matter from a large ocean-going container vessel were sampled as it slowed and switched from high-sulfur to low-sulfur fuel as it transited into regulated coastal waters of California. Reduction in emission factors (EFs) of sulfur dioxide (SO₂), particulate matter, particulate sulfate and cloud condensation nuclei were substantial (≥ 90%). EFs for particulate organic matter decreased by 70%. Black carbon (BC) EFs were reduced by 41%. When the measured emission reductions, brought about by compliance with the California fuel quality regulation and participation in the vessel speed reduction (VSR) program, are placed in a broader context, warming from reductions in the indirect effect of SO₄ would dominate any radiative changes due to the emissions changes. Within regulated waters absolute emission reductions exceed 88% for almost all measured gas and particle phase species. The analysis presented provides direct estimations of the emissions reductions that can be realized by California fuel quality regulation and VSR program, in addition to providing new information relevant to potential health and climate impact of reduced fuel sulfur content, fuel quality and vessel speed reductions.

Reliability considerations of a fuel cell backup power system for telecom applications

NASA Astrophysics Data System (ADS)

Serincan, Mustafa Fazil

2016-03-01

A commercial fuel cell backup power unit is tested in real life operating conditions at a base station of a Turkish telecom operator. The fuel cell system responds to 256 of 260 electric power outages successfully, providing the required power to the base station. Reliability of the fuel cell backup power unit is found to be 98.5% at the system level. On the other hand, a qualitative reliability analysis at the component level is carried out. Implications of the power management algorithm on reliability is discussed. Moreover, integration of the backup power unit to the base station ecosystem is reviewed in the context of reliability. Impact of inverter design on the stability of the output power is outlined. Significant current harmonics are encountered when a generic inverter is used. However, ripples are attenuated significantly when a custom design inverter is used. Further, fault conditions are considered for real world case studies such as running out of hydrogen, a malfunction in the system, or an unprecedented operating scheme. Some design guidelines are suggested for hybridization of the backup power unit for an uninterrupted operation.

Potential Occupational Exposures and Health Risks Associated with Biomass-Based Power Generation.

PubMed

Rohr, Annette C; Campleman, Sharan L; Long, Christopher M; Peterson, Michael K; Weatherstone, Susan; Quick, Will; Lewis, Ari

2015-07-22

Biomass is increasingly being used for power generation; however, assessment of potential occupational health and safety (OH&S) concerns related to usage of biomass fuels in combustion-based generation remains limited. We reviewed the available literature on known and potential OH&S issues associated with biomass-based fuel usage for electricity generation at the utility scale. We considered three potential exposure scenarios--pre-combustion exposure to material associated with the fuel, exposure to combustion products, and post-combustion exposure to ash and residues. Testing of dust, fungal and bacterial levels at two power stations was also undertaken. Results indicated that dust concentrations within biomass plants can be extremely variable, with peak levels in some areas exceeding occupational exposure limits for wood dust and general inhalable dust. Fungal spore types, identified as common environmental species, were higher than in outdoor air. Our review suggests that pre-combustion risks, including bioaerosols and biogenic organics, should be considered further. Combustion and post-combustion risks appear similar to current fossil-based combustion. In light of limited available information, additional studies at power plants utilizing a variety of technologies and biomass fuels are recommended.

Potential Occupational Exposures and Health Risks Associated with Biomass-Based Power Generation

PubMed Central

Rohr, Annette C.; Campleman, Sharan L.; Long, Christopher M.; Peterson, Michael K.; Weatherstone, Susan; Quick, Will; Lewis, Ari

2015-01-01

Biomass is increasingly being used for power generation; however, assessment of potential occupational health and safety (OH&S) concerns related to usage of biomass fuels in combustion-based generation remains limited. We reviewed the available literature on known and potential OH&S issues associated with biomass-based fuel usage for electricity generation at the utility scale. We considered three potential exposure scenarios—pre-combustion exposure to material associated with the fuel, exposure to combustion products, and post-combustion exposure to ash and residues. Testing of dust, fungal and bacterial levels at two power stations was also undertaken. Results indicated that dust concentrations within biomass plants can be extremely variable, with peak levels in some areas exceeding occupational exposure limits for wood dust and general inhalable dust. Fungal spore types, identified as common environmental species, were higher than in outdoor air. Our review suggests that pre-combustion risks, including bioaerosols and biogenic organics, should be considered further. Combustion and post-combustion risks appear similar to current fossil-based combustion. In light of limited available information, additional studies at power plants utilizing a variety of technologies and biomass fuels are recommended. PMID:26206568

Fuel cells at the crossroads : attitudes regarding the investment climate for the US fuel cell industry and a projection of industry job creation potential.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

2004-05-27

Fuel Cells at the Crossroads examines financial community and fuel cell industry views on the investment climate for the fuel cell industry. It also explores the investment history of the US fuel cell industry and projects potential future job creation. The scope of the study included the transportation, stationary power generation and portable sectors. Interviews were conducted with industry and financial experts. The results of the interviews provide a snapshot of industry perspective just prior to President Bush's endorsement of a hydrogen economy in his 2003 State of the Union address. In April 2003, we conducted a spot check tomore » test whether the State of the Union address had changed opinions. We found little change among the financial and investment communities, but some guarded new optimism among industry leaders. The general outlook of our sample was cautiously hopeful. There is no question, however, that the current climate is one of great uncertainty, particularly when compared with the enthusiasm that existed just a few years ago. Among other things: (1) Respondents generally believed that the energy industry will undergo profound change over the next few decades, resulting in some form of hydrogen economy. They acknowledged, however, that huge technology and cost hurdles must be overcome to achieve a hydrogen economy. (2) Respondents were worried about the future of the industry, including timeframes for market development, foreign competition, technical problems, and the current poor investment environment. (3) Respondents generally believed that the US federal government must provide strong leadership to ensure American leadership in the fuel cell industry. They believe that governments in Europe and Japan are highly committed to fuel cells, thus providing European and Japanese companies with significant advantages. (4) Respondents frequently mentioned several areas of concern, including the situation in Iraq, the increased commitment to fuel cells in Europe, and recent actions by Toyota and Honda.« less

Heat Recuperator Engineering for an ARL Liquid-Fueled Thermophotovoltaic Power Source Demonstrator

DTIC Science & Technology

2014-09-01

using logistics and multiple other fuels. Some potential technologies include thermoelectric , thermophotovoltaic (TPV), and thermionic. For these... thermoelectric , thermophotovoltaic (TPV), and thermionic. For these technologies, thermal efficiency is critical to achieve high energy density and thermal-to... thermoelectric and TPV. The exhaust gas will be above this temperature, but more than 50% of the thermal power of the combustor can be lost to the exhaust

Dangerous (toxic) atmospheres in UK wood pellet and wood chip fuel storage.

PubMed

Simpson, Andrew T; Hemingway, Michael A; Seymour, Cliff

2016-09-01

There is growing use of wood pellet and wood chip boilers in the UK. Elsewhere fatalities have been reported, caused by carbon monoxide poisoning following entry into wood pellet storage areas. The aim of this work was to obtain information on how safely these two fuels are being stored in the UK. Site visits were made to six small-scale boiler systems and one large-scale pellet warehouse, to assess storage practice, risk management systems and controls, user knowledge, and potential for exposure to dangerous atmospheres. Real time measurements were made of gases in the store rooms and during laboratory tests on pellets and chips. Volatile organic compounds (VOCs) emitted and the microbiological content of the fuel was also determined. Knowledge of the hazards associated with these fuels, including confined space entry, was found to be limited at the smaller sites, but greater at the large pellet warehouse. There has been limited risk communication between companies supplying and maintaining boilers, those manufacturing and supplying fuel, and users. Risk is controlled by restricting access to the store rooms with locked entries; some store rooms have warning signs and carbon monoxide alarms. Nevertheless, some store rooms are accessed for inspection and maintenance. Laboratory tests showed that potentially dangerous atmospheres of carbon monoxide and carbon dioxide, with depleted levels of oxygen may be generated by these fuels, but this was not observed at the sites visited. Unplanned ventilation within store rooms was thought to be reducing the build-up of dangerous atmospheres. Microbiological contamination was confined to wood chips.

Dangerous (toxic) atmospheres in UK wood pellet and wood chip fuel storage

PubMed Central

Simpson, Andrew T.; Hemingway, Michael A.; Seymour, Cliff

2016-01-01

ABSTRACT There is growing use of wood pellet and wood chip boilers in the UK. Elsewhere fatalities have been reported, caused by carbon monoxide poisoning following entry into wood pellet storage areas. The aim of this work was to obtain information on how safely these two fuels are being stored in the UK. Site visits were made to six small-scale boiler systems and one large-scale pellet warehouse, to assess storage practice, risk management systems and controls, user knowledge, and potential for exposure to dangerous atmospheres. Real time measurements were made of gases in the store rooms and during laboratory tests on pellets and chips. Volatile organic compounds (VOCs) emitted and the microbiological content of the fuel was also determined. Knowledge of the hazards associated with these fuels, including confined space entry, was found to be limited at the smaller sites, but greater at the large pellet warehouse. There has been limited risk communication between companies supplying and maintaining boilers, those manufacturing and supplying fuel, and users. Risk is controlled by restricting access to the store rooms with locked entries; some store rooms have warning signs and carbon monoxide alarms. Nevertheless, some store rooms are accessed for inspection and maintenance. Laboratory tests showed that potentially dangerous atmospheres of carbon monoxide and carbon dioxide, with depleted levels of oxygen may be generated by these fuels, but this was not observed at the sites visited. Unplanned ventilation within store rooms was thought to be reducing the build-up of dangerous atmospheres. Microbiological contamination was confined to wood chips. PMID:27030057

The climate responsibilities of the fossil fuel industry: why the Paris Agreement goals require an end to growth

NASA Astrophysics Data System (ADS)

Trout, K.; Muttitt, G.; Kretzmann, S.; Stockman, L.; Doukas, A.

2017-12-01

In December 2015, governments agreed in Paris to limit global average temperature rise to well below 2°C, and to aim to limit it to 1.5°C, compared to pre-industrial levels. Achieving these goals would require greenhouse gas emissions to reach net zero early in the second half of this century, and consequently most fossil fuel use to be phased out. This has clear implications for fossil fuel industry, and shines light on what should be expected of the industry in its business decisions - complementing the discussion of the industry's role in the scientific debate. This presentation shares the results to date of ongoing research into the committed emissions from oilfields, gasfields and coal mines, compared to carbon budgets. Building on prior work on fossil fuel reserves (notably Meinshausen 2009), our research focuses just on the developed reserves, from already-producing fields and mines. We estimate developed reserves of oil and gas using industry databases, and of coal using analysis by the International Energy Agency, and compare with carbon budgets published in the IPCC's 5th Assessment Report. The key findings are that: Developed reserves of oil, gas, and coal are more than we can afford to burn while keeping likely warming below 2°C. Developed reserves of oil and gas alone would take the world beyond 1.5°C. The implications are that development of any new fields or mines will either push the world beyond agreed climate limits, or cause some existing extraction assets to become stranded. This suggests that fossil fuel companies should stop developing new infrastructure, and governments should oversee a managed decline of the industry over the coming decades, combined with an upscaling of clean energy, as existing fossil fuel reserves are depleted.

Physiological tolerance and stoichiometric potential of cyanobacteria for hydrocarbon fuel production.

PubMed

Kämäräinen, Jari; Knoop, Henning; Stanford, Natalie J; Guerrero, Fernando; Akhtar, M Kalim; Aro, Eva-Mari; Steuer, Ralf; Jones, Patrik R

2012-11-30

Cyanobacteria are capable of directly converting sunlight, carbon dioxide and water into hydrocarbon fuel or precursors thereof. Many biological and non-biological factors will influence the ability of such a production system to become economically sustainable. We evaluated two factors in engineerable cyanobacteria which could potentially limit economic sustainability: (i) tolerance of the host to the intended end-product, and (ii) stoichiometric potential for production. Alcohols, when externally added, inhibited growth the most, followed by aldehydes and acids, whilst alkanes were the least inhibitory. The growth inhibition became progressively greater with increasing chain-length for alcohols, whilst the intermediate C6 alkane caused more inhibition than both C3 and C11 alkane. Synechocystis sp. PCC 6803 was more tolerant to some of the tested chemicals than Synechococcus elongatus PCC 7942, particularly ethanol and undecane. Stoichiometric evaluation of the potential yields suggested that there is no difference in the potential productivity of harvestable energy between any of the studied fuels, with the exception of ethylene, for which maximal stoichiometric yield is considerably lower. In summary, it was concluded that alkanes would constitute the best choice metabolic end-product for fuel production using cyanobacteria if high-yielding strains can be developed. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of refractory-metal-clad uranium nitride and uranium dioxide fuel pins after irradiation for times up to 10 450 hours at 990 C

NASA Technical Reports Server (NTRS)

Bowles, K. J.; Gluyas, R. E.

1975-01-01

The effects of some materials variables on the irradiation performance of fuel pins for a lithium-cooled space power reactor design concept were examined. The variables studied were UN fuel density, fuel composition, and cladding alloy. All pins were irradiated at about 990 C in a thermal neutron environment to the design fuel burnup. An 85-percent dense UN fuel gave the best overall results in meeting the operational goals. The T-111 cladding on all specimens was embrittled, possibly by hydrogen in the case of the UN fuel and by uranium and oxygen in the case of the UO2 fuel. Tests with Cb-1Zr cladding indicate potential use of this cladding material. The UO2 fueled specimens met the operational goals of less than 1 percent cladding strain, but other factors make UO2 less attractive than low-density UN for the contemplated space power reactor use.

Untangling the confusion around land carbon science and climate change mitigation policy

NASA Astrophysics Data System (ADS)

Mackey, Brendan; Prentice, I. Colin; Steffen, Will; House, Joanna I.; Lindenmayer, David; Keith, Heather; Berry, Sandra

2013-06-01

Depletion of ecosystem carbon stocks is a significant source of atmospheric CO2 and reducing land-based emissions and maintaining land carbon stocks contributes to climate change mitigation. We summarize current understanding about human perturbation of the global carbon cycle, examine three scientific issues and consider implications for the interpretation of international climate change policy decisions, concluding that considering carbon storage on land as a means to 'offset' CO2 emissions from burning fossil fuels (an idea with wide currency) is scientifically flawed. The capacity of terrestrial ecosystems to store carbon is finite and the current sequestration potential primarily reflects depletion due to past land use. Avoiding emissions from land carbon stocks and refilling depleted stocks reduces atmospheric CO2 concentration, but the maximum amount of this reduction is equivalent to only a small fraction of potential fossil fuel emissions.

Impact of organosulfur content on diesel fuel stability and implications for carbon steel corrosion.

PubMed

Lyles, Christopher N; Aktas, Deniz F; Duncan, Kathleen E; Callaghan, Amy V; Stevenson, Bradley S; Suflita, Joseph M

2013-06-04

Ultralow sulfur diesel (ULSD) fuel has been integrated into the worldwide fuel infrastructure to help meet a variety of environmental regulations. However, desulfurization alters the properties of diesel fuel in ways that could potentially impact its biological stability. Fuel desulfurization might predispose ULSD to biodeterioration relative to sulfur-rich fuels and in marine systems accelerate rates of sulfate reduction, sulfide production, and carbon steel biocorrosion. To test such prospects, an inoculum from a seawater-compensated ballast tank was amended with fuel from the same ship or with refinery fractions of ULSD, low- (LSD), and high sulfur diesel (HSD) and monitored for sulfate depletion. The rates of sulfate removal in incubations amended with the refinery fuels were elevated relative to the fuel-unamended controls but statistically indistinguishable (∼50 μM SO4/day), but they were found to be roughly twice as fast (∼100 μM SO4/day) when the ship's own diesel was used as a source of carbon and energy. Thus, anaerobic hydrocarbon metabolism likely occurred in these incubations regardless of fuel sulfur content. Microbial community structure from each incubation was also largely independent of the fuel amendment type, based on molecular analysis of 16S rRNA sequences. Two other inocula known to catalyze anaerobic hydrocarbon metabolism showed no differences in fuel-associated sulfate reduction or methanogenesis rates between ULSD, LSD, and HSD. These findings suggest that the stability of diesel is independent of the fuel organosulfur compound status and reasons for the accelerated biocorrosion associated with the use of ULSD should be sought elsewhere.

Life cycle environmental impacts of three products derived from wild-caught Antarctic krill (Euphausia superba).

PubMed

Parker, Robert W R; Tyedmers, Peter H

2012-05-01

Concern has been voiced in recent years regarding the environmental implications of the Antarctic krill fishery. Attention has focused primarily on ecological concerns, whereas other environmental aspects, including potentially globally problematic emissions and material and energy demands, have not been examined in detail. Here we apply life cycle assessment to measure the contributions of krill meal, oil, and omega-3 capsules to global warming, ozone depletion, acidification, eutrophication, energy use, and biotic resource use. Supply chains of one krill fishing and processing company, Aker BioMarine of Norway, were assessed. Impacts of krill products were found to be driven primarily by the combustion of fossil fuels onboard the fishing vessel and a transport/resupply vessel. Approximately 190 L of fuel are burned per tonne of raw krill landed, markedly higher than fuel inputs to reduction fisheries targeting other species. In contrast, the biotic resource use associated with extracting krill is relatively low compared to that of other reduction fisheries. Results of this study provide insight into the broader environmental implications of the krill fishery, comparisons between products derived from krill and other species targeted for reduction, opportunities for improving the fishery's performance, and a baseline against which to measure future performance. © 2012 American Chemical Society

Support schemes and ownership structures - the policy context for fuel cell based micro-combined heat and power

NASA Astrophysics Data System (ADS)

Schroeder, Sascha Thorsten; Costa, Ana; Obé, Elisabeth

In recent years, fuel cell based micro-combined heat and power (mCHP) has received increasing attention due to its potential contribution to European energy policy goals, i.e., sustainability, competitiveness and security of supply. Besides technical advances, regulatory framework and ownership structures are of crucial importance in order to achieve greater diffusion of the technology in residential applications. This paper analyses the interplay of policy and ownership structures for the future deployment of mCHP. Furthermore, it regards the three country cases Denmark, France and Portugal. Firstly, the implications of different kinds of support schemes on investment risk and the diffusion of a technology are explained conceptually. Secondly, ownership arrangements are addressed. Then, a cross-country comparison on present support schemes for mCHP and competing technologies discusses the national implementation of European legislation in Denmark, France and Portugal. Finally, resulting implications for ownership arrangements on the choice of support scheme are explained. From a conceptual point of view, investment support, feed-in tariffs and price premiums are the most appropriate schemes for fuel cell mCHP. This can be used for improved analysis of operational strategies. The interaction of this plethora of elements necessitates careful balancing from a private- and socio-economic point of view.

Observation of Flat Electron Temperature Profiles in the Lithium Tokamak Experiment

DOE PAGES

Boyle, D. P.; Majeski, R.; Schmitt, J. C.; ...

2017-07-05

It has been predicted for over a decade that low-recycling plasma-facing components in fusion devices would allow high edge temperatures and flat or nearly flat temperature profiles. In recent experiments with lithium wall coatings in the Lithium Tokamak Experiment (LTX), a hot edge ( > 200 eV ) and flat electron temperature profiles have been measured following the termination of external fueling. In this work, reduced recycling was demonstrated by retention of ~ 60% of the injected hydrogen in the walls following the discharge. Electron energy confinement followed typical Ohmic confinement scaling during fueling, but did not decrease with densitymore » after fueling terminated, ultimately exceeding the scaling by ~ 200% . Lastly, achievement of the low-recycling, hot edge regime has been an important goal of LTX and lithium plasma-facing component research in general, as it has potentially significant implications for the operation, design, and cost of fusion devices.« less

Observation of Flat Electron Temperature Profiles in the Lithium Tokamak Experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyle, D. P.; Majeski, R.; Schmitt, J. C.

It has been predicted for over a decade that low-recycling plasma-facing components in fusion devices would allow high edge temperatures and flat or nearly flat temperature profiles. In recent experiments with lithium wall coatings in the Lithium Tokamak Experiment (LTX), a hot edge ( > 200 eV ) and flat electron temperature profiles have been measured following the termination of external fueling. In this work, reduced recycling was demonstrated by retention of ~ 60% of the injected hydrogen in the walls following the discharge. Electron energy confinement followed typical Ohmic confinement scaling during fueling, but did not decrease with densitymore » after fueling terminated, ultimately exceeding the scaling by ~ 200% . Lastly, achievement of the low-recycling, hot edge regime has been an important goal of LTX and lithium plasma-facing component research in general, as it has potentially significant implications for the operation, design, and cost of fusion devices.« less

Bioenergy for sustainable development: An African context

NASA Astrophysics Data System (ADS)

Mangoyana, Robert Blessing

This paper assesses the sustainability concerns of bioenergy systems against the prevailing and potential long term conditions in Sub-Saharan Africa with a special attention on agricultural and forestry waste, and cultivated bioenergy sources. Existing knowledge and processes about bioenergy systems are brought into a “sustainability framework” to support debate and decisions about the implementation of bioenergy systems in the region. Bioenergy systems have been recommended based on the potential to (i) meet domestic energy demand and reduce fuel importation (ii) diversify rural economies and create employment (iii) reduce poverty, and (iv) provide net energy gains and positive environmental impacts. However, biofuels will compete with food crops for land, labour, capital and entrepreneurial skills. Moreover the environmental benefits of some feedstocks are questionable. These challenges are, however, surmountable. It is concluded that biomass energy production could be an effective way to achieve sustainable development for bioenergy pathways that (i) are less land intensive, (ii) have positive net energy gains and environmental benefits, and (iii) provide local socio-economic benefits. Feasibility evaluations which put these issues into perspective are vital for sustainable application of agricultural and forest based bioenergy systems in Sub-Saharan Africa. Such evaluations should consider the long run potential of biofuels accounting for demographic, economic and technological changes and the related implications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Yeon Soo; Jeong, G. Y.; Sohn, D. -S.

U-Mo/Al dispersion fuel is currently under development in the DOE’s Material Management and Minimization program to convert HEU-fueled research reactors to LEU-fueled reactors. In some demanding conditions in high-power and high-performance reactors, large pores form in the interaction layers between the U-Mo fuel particles and the Al matrix, which pose a potential to cause fuel failure. In this study, comprehension of the formation and growth of these pores was explored. As a product, a model to predict pore growth and porosity increase was developed. Well-characterized in-pile data from reduced-size plates were used to fit the model parameters. A data setmore » of full-sized plates, independent and distinctively different from those used to fit the model parameters, was used to examine the accuracy of the model.« less

Evaluation of advanced lift concepts and potential fuel conservation for short-haul aircraft

NASA Technical Reports Server (NTRS)

Sweet, H. S.; Renshaw, J. H.; Bowden, M. K.

1975-01-01

The effect of different field lengths, cruise requirements, noise level, and engine cycle characteristics on minimizing fuel consumption and minimizing operating cost at high fuel prices were evaluated for some advanced short-haul aircraft. The conceptual aircraft were designed for 148 passengers using the upper surface-internally blown jet flap, the augmentor wing, and the mechanical flap lift systems. Advanced conceptual STOL engines were evaluated as well as a near-term turbofan and turboprop engine. Emphasis was given to designs meeting noise levels equivalent to 95-100 EPNdB at 152 m (500 ft) sideline.

Neurophysiological, metabolic and cellular compartments that drive neurovascular coupling and neuroimaging signals

PubMed Central

Moreno, Andrea; Jego, Pierrick; de la Cruz, Feliberto; Canals, Santiago

2013-01-01

Complete understanding of the mechanisms that coordinate work and energy supply of the brain, the so called neurovascular coupling, is fundamental to interpreting brain energetics and their influence on neuronal coding strategies, but also to interpreting signals obtained from brain imaging techniques such as functional magnetic resonance imaging. Interactions between neuronal activity and cerebral blood flow regulation are largely compartmentalized. First, there exists a functional compartmentalization in which glutamatergic peri-synaptic activity and its electrophysiological events occur in close proximity to vascular responses. Second, the metabolic processes that fuel peri-synaptic activity are partially segregated between glycolytic and oxidative compartments. Finally, there is cellular segregation between astrocytic and neuronal compartments, which has potentially important implications on neurovascular coupling. Experimental data is progressively showing a tight interaction between the products of energy consumption and neurotransmission-driven signaling molecules that regulate blood flow. Here, we review some of these issues in light of recent findings with special attention to the neuron-glia interplay on the generation of neuroimaging signals. PMID:23543907

Ocean acidification: the other CO2 problem.

PubMed

Doney, Scott C; Fabry, Victoria J; Feely, Richard A; Kleypas, Joan A

2009-01-01

Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms (both calcifying and noncalcifying). The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research. Although ocean pH has varied in the geological past, paleo-events may be only imperfect analogs to current conditions.

Strategies for Reversing the Effects of Metabolic Disorders Induced as a Consequence of Developmental Programming

PubMed Central

Vickers, M. H.; Sloboda, D. M.

2012-01-01

Obesity and the metabolic syndrome have reached epidemic proportions worldwide with far-reaching health care and economic implications. The rapid increase in the prevalence of these disorders suggests that environmental and behavioral influences, rather than genetic causes, are fueling the epidemic. The developmental origins of health and disease hypothesis has highlighted the link between the periconceptual, fetal, and early infant phases of life and the subsequent development of metabolic disorders in later life. In particular, the impact of poor maternal nutrition on susceptibility to later life metabolic disease in offspring is now well documented. Several studies have now shown, at least in experimental animal models, that some components of the metabolic syndrome, induced as a consequence of developmental programming, are potentially reversible by nutritional or targeted therapeutic interventions during windows of developmental plasticity. This review will focus on critical windows of development and possible therapeutic avenues that may reduce metabolic and obesogenic risk following an adverse early life environment. PMID:22783205

Jumps in electric potential and in temperature at the electrode surfaces of the solid oxide fuel cell

NASA Astrophysics Data System (ADS)

Kjelstrup, S.; Bedeaux, D.

1997-02-01

The electric potential profile and the temperature profile across a formation cell have been derived for the first time, using irreversible thermodynamics for bulk and surface systems. The method was demonstrated with the solid oxide fuel cell. The expression for the cell potential reduces to the classical formula when we assume equilibrium for polarized oxygen atoms across the electrolyte. Using data from the literature, we show for some likely assumptions, how the cell potential is generated at the anode, and how the energy is dissipated throughout the cell. The thermal gradient amounts to 5 × 10 8 Km -1 when the current density is 10 4 Am -2 and the thermal resistance of the surface scales like the electrical resistance.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion.

PubMed

Ren, G; Yan, J; Liu, J; Lan, K; Chen, Y H; Huo, W Y; Fan, Z; Zhang, X; Zheng, J; Chen, Z; Jiang, W; Chen, L; Tang, Q; Yuan, Z; Wang, F; Jiang, S; Ding, Y; Zhang, W; He, X T

2017-04-21

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 10^{14}-10^{15}  W/cm^{2} intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Y_{n} to be related to the laser energy E_{L}, the hohlraum radius R_{h}, and the pulse duration τ through a scaling law of Y_{n}∝(E_{L}/R_{h}^{1.2}τ^{0.2})^{2.5}. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

NASA Astrophysics Data System (ADS)

Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

2017-04-01

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

An evaluation of negative-emission transportation-energy systems for the US

NASA Astrophysics Data System (ADS)

Larson, E. D.; Meerman, J. C.

2017-12-01

We present technical, economic, and carbon footprint evaluations of alternative technological pathways for negative emissions transportation energy from sustainably-sourced lignocellulosic biomass in the U.S. We combine the understanding of alternative technological pathways with spatially-resolved projections of the sustainable supply of lignocellulosic biomass and with future demands for transportation services to provide insights on the extent to which biomass-based energy might be able to help meet mid-century U.S. transportation energy needs and carbon mitigation targets. Biomass conversion routes included in our evaluations are biochemical, biocatalytic, thermocatalytic hydropyrolysis, and thermochemical gasification/synthesis to produce liquid fuels fungible with petroleum-derived fuels, and thermochemical conversion to hydrogen (for fuel cell vehicles) or electricity (for battery electric vehicles). Lifecycle net negative emissions are achieved for each system via soil carbon buildup during biomass production and/or capture of CO2 at the conversion facility and underground storage. Co-processing of some fossil fuel is considered in some cases to improve economics. For self-consistency in the analysis across systems, a common set of technical, economic and carbon footprint input parameters are adopted. Capital cost estimates are harmonized by taking into account scale of facilities, level of engineering details available in generating a cost estimate, and the technology readiness level (TRL) of components and the process as a whole. Implications for economics of future commercial plants are investigated, considering alternative prospective reductions in capital and operating costs (via "learning by doing") and alternative carbon mitigation policies.

Progress in understanding fission-product behaviour in coated uranium-dioxide fuel particles

NASA Astrophysics Data System (ADS)

Barrachin, M.; Dubourg, R.; Kissane, M. P.; Ozrin, V.

2009-03-01

Supported by results of calculations performed with two analytical tools (MFPR, which takes account of physical and chemical mechanisms in calculating the chemical forms and physical locations of fission products in UO2, and MEPHISTA, a thermodynamic database), this paper presents an investigation of some important aspects of the fuel microstructure and chemical evolutions of irradiated TRISO particles. The following main conclusions can be identified with respect to irradiated TRISO fuel: first, the relatively low oxygen potential within the fuel particles with respect to PWR fuel leads to chemical speciation that is not typical of PWR fuels, e.g., the relatively volatile behaviour of barium; secondly, the safety-critical fission-product caesium is released from the urania kernel but the buffer and pyrolytic-carbon coatings could form an important chemical barrier to further migration (i.e., formation of carbides). Finally, significant releases of fission gases from the urania kernel are expected even in nominal conditions.

Cyanoborohydride-based ionic liquids as green aerospace bipropellant fuels.

PubMed

Zhang, Qinghua; Yin, Ping; Zhang, Jiaheng; Shreeve, Jean'ne M

2014-06-02

In propellant systems, the most common bipropellants are composed of two chemicals, a fuel (or reducer) and an oxidizer. Currently, the choices for propellant fuels rely mainly on hydrazine and its methylated derivatives, even though they are extremely toxic, highly volatile, sensitive to adiabatic compression (risk of detonation), and, therefore, difficult to handle. With this background, the search for alternative green propellant fuels has been an urgent goal of space science. In this study, a new family of cyanoborohydride-based ionic liquids (ILs) with properties and performances comparable to hydrazine derivatives were designed and synthesized. These new ILs as bipropellant fuels, have some unique advantages including negligible vapor pressure, ultra-short ignition delay (ID) time, and reduced synthetic and storage costs, thereby showing great application potential as environmentally friendly fuels in bipropellant formulations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Land cover, more than monthly fire weather, drives fire-size distribution in Southern Québec forests: Implications for fire risk management

PubMed Central

Marchal, Jean; Cumming, Steve G.; McIntire, Eliot J. B.

2017-01-01

Fire activity in North American forests is expected to increase substantially with climate change. This would represent a growing risk to human settlements and industrial infrastructure proximal to forests, and to the forest products industry. We modelled fire size distributions in southern Québec as functions of fire weather and land cover, thus explicitly integrating some of the biotic interactions and feedbacks in a forest-wildfire system. We found that, contrary to expectations, land-cover and not fire weather was the primary driver of fire size in our study region. Fires were highly selective on fuel-type under a wide range of fire weather conditions: specifically, deciduous forest, lakes and to a lesser extent recently burned areas decreased the expected fire size in their vicinity compared to conifer forest. This has large implications for fire risk management in that fuels management could reduce fire risk over the long term. Our results imply, for example, that if 30% of a conifer-dominated landscape were converted to hardwoods, the probability of a given fire, occurring in that landscape under mean fire weather conditions, exceeding 100,000 ha would be reduced by a factor of 21. A similarly marked but slightly smaller effect size would be expected under extreme fire weather conditions. We attribute the decrease in expected fire size that occurs in recently burned areas to fuel availability limitations on fires spread. Because regenerating burned conifer stands often pass through a deciduous stage, this would also act as a negative biotic feedback whereby the occurrence of fires limits the size of nearby future for some period of time. Our parameter estimates imply that changes in vegetation flammability or fuel availability after fires would tend to counteract shifts in the fire size distribution favoring larger fires that are expected under climate warming. Ecological forecasts from models neglecting these feedbacks may markedly overestimate the consequences of climate warming on fire activity, and could be misleading. Assessments of vulnerability to climate change, and subsequent adaptation strategies, are directly dependent on integrated ecological forecasts. Thus, we stress the need to explicitly incorporate land-cover’s direct effects and feedbacks in simulation models of coupled climate–fire–fuels systems. PMID:28609467

Land cover, more than monthly fire weather, drives fire-size distribution in Southern Québec forests: Implications for fire risk management.

PubMed

Marchal, Jean; Cumming, Steve G; McIntire, Eliot J B

2017-01-01

Fire activity in North American forests is expected to increase substantially with climate change. This would represent a growing risk to human settlements and industrial infrastructure proximal to forests, and to the forest products industry. We modelled fire size distributions in southern Québec as functions of fire weather and land cover, thus explicitly integrating some of the biotic interactions and feedbacks in a forest-wildfire system. We found that, contrary to expectations, land-cover and not fire weather was the primary driver of fire size in our study region. Fires were highly selective on fuel-type under a wide range of fire weather conditions: specifically, deciduous forest, lakes and to a lesser extent recently burned areas decreased the expected fire size in their vicinity compared to conifer forest. This has large implications for fire risk management in that fuels management could reduce fire risk over the long term. Our results imply, for example, that if 30% of a conifer-dominated landscape were converted to hardwoods, the probability of a given fire, occurring in that landscape under mean fire weather conditions, exceeding 100,000 ha would be reduced by a factor of 21. A similarly marked but slightly smaller effect size would be expected under extreme fire weather conditions. We attribute the decrease in expected fire size that occurs in recently burned areas to fuel availability limitations on fires spread. Because regenerating burned conifer stands often pass through a deciduous stage, this would also act as a negative biotic feedback whereby the occurrence of fires limits the size of nearby future for some period of time. Our parameter estimates imply that changes in vegetation flammability or fuel availability after fires would tend to counteract shifts in the fire size distribution favoring larger fires that are expected under climate warming. Ecological forecasts from models neglecting these feedbacks may markedly overestimate the consequences of climate warming on fire activity, and could be misleading. Assessments of vulnerability to climate change, and subsequent adaptation strategies, are directly dependent on integrated ecological forecasts. Thus, we stress the need to explicitly incorporate land-cover's direct effects and feedbacks in simulation models of coupled climate-fire-fuels systems.

Lignin depolymerization and upgrading via fast pyrolysis and electrocatalysis for the production of liquid fuels and value-added products

NASA Astrophysics Data System (ADS)

Garedew, Mahlet

The production of liquid hydrocarbon fuels from biomass is needed to replace fossil fuels, which are decreasing in supply at an unsustainable rate. Renewable fuels also address the rising levels of greenhouse gases, an issue for which the Intergovernmental Panel on Climate Change implicated humanity in 2013. In response, the Energy Independence and Security Act (EISA) mandates the production of 21 billion gallons of advanced biofuels by 2022. Biomass fast pyrolysis (BFP) uses heat (400-600 °C) without oxygen to convert biomass to liquids fuel precursors offering an alternative to fossil fuels and a means to meet the EISA mandate. The major product, bio-oil, can be further upgraded to liquid hydrocarbon fuels, while biochar can serve as a solid fuel or soil amendment. The combustible gas co-product is typically burned for process heat. Though the most valuable of the pyrolysis products, the liquid bio-oil is highly oxygenated, corrosive, low in energy content and unstable during storage. As a means of improving bio-oil properties, electrocatalytic hydrogenation (ECH) is employed to reduce and deoxygenate reactive compounds. This work specifically focuses on lignin as a feed material for BFP. As lignin comprises up to 30% of the mass and 40% of the energy stored in biomass, it offers great potential for the production of liquid fuels and value-added products by utilizing fast pyrolysis as a conversion method coupled with electrocatalysis as an upgrading method.

Tradable credits system design and cost savings for a national low carbon fuel standard for road transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, Jonathan; Leiby, Paul N.

2012-06-11

This research examines the economic implications of different designs for a national low carbon fuel standard (NLCFS) for the road transportation sector. A NLCFS based on the average Carbon Intensity (CI) of all fuels sold in the gasoline and diesel markets will generate an incentive for fuel suppliers to reduce the measured CI of their petroleum fuels. The economic impacts of a NLCFS are fundamentally determined by: the availability of low carbon fuels; the compliance path; the reference level CI of the fuel baseline; and the degree of flexibility in the credit system. To quantitatively examine the implications of amore » NLCFS, we created the Transportation Regulation and Credit Trading (TRACT) Model. With TRACT, we model a NLCFS credit trading system among profit maximizing fuel suppliers for light- and heavy-duty vehicle fuel use for the United States from 2012 - 2030. Given the wide range of cost and availability of biofuels, we find that credit trading across gasoline and diesel fuel markets combined with credit banking can significantly reduce compliance costs and stabilize credit prices. We make policy recommendations on how to combine a NLCFS with other existing regulations for transportation fuels.« less

In utero fuel homeostasis: Lessons for a clinician.

PubMed

Rao, P N Suman; Shashidhar, A; Ashok, C

2013-01-01

Fetus exists in a complex, dynamic, and yet intriguing symbiosis with its mother as far as fuel metabolism is concerned. Though the dependence on maternal fuel is nearly complete to cater for its high requirement, the fetus is capable of some metabolism of its own. The first half of gestation is a period of maternal anabolism and storage whereas the second half results in exponential fetal growth where maternal stores are mobilized. Glucose is the primary substrate for energy production in the fetus though capable of utilizing alternate sources like lactate, ketoacids, amino acids, fatty acids, and glycogen as fuel under special circumstances. Key transporters like glucose transporters (GLUT) are responsible for preferential transfers, which are in turn regulated by complex interaction of maternal and fetal hormones. Amino acids are preferentially utilized for growth and essential fatty acids for development of brain and retina. Insulin, insulin like growth factors, glucagon, catecholamines, and letpin are the hormones implicated in this fascinating process. Hormonal regulation of metabolic substrate utilization and anabolism in the fetus is secondary to the supply of nutrient substrates. The knowledge of fuel homeostasis is crucial for a clinician caring for pregnant women and neonates to manage disorders of metabolism (diabetes), growth (intrauterine growth restriction), and transitional adaptation (hypoglycemia).

Corrosion testing of candidates for the alkaline fuel cell cathode

NASA Technical Reports Server (NTRS)

Singer, Joseph; Fielder, William L.

1990-01-01

Current/voltage data have been obtained for specially made corrosion electrodes of some oxides and of gold materials for the purpose of developing a screening test of catalysts and supports for use at the cathode of the alkaline fuel cell. The data consist of measurements of current at fixed potentials and cyclic voltammograms. These data will have to be correlated with longtime performance data in order to evaluate fully this approach to corrosion screening.

Dimethyl ether (DME) as an alternative fuel

NASA Astrophysics Data System (ADS)

Semelsberger, Troy A.; Borup, Rodney L.; Greene, Howard L.

With ever growing concerns on environmental pollution, energy security, and future oil supplies, the global community is seeking non-petroleum based alternative fuels, along with more advanced energy technologies (e.g., fuel cells) to increase the efficiency of energy use. The most promising alternative fuel will be the fuel that has the greatest impact on society. The major impact areas include well-to-wheel greenhouse gas emissions, non-petroleum feed stocks, well-to-wheel efficiencies, fuel versatility, infrastructure, availability, economics, and safety. Compared to some of the other leading alternative fuel candidates (i.e., methane, methanol, ethanol, and Fischer-Tropsch fuels), dimethyl ether appears to have the largest potential impact on society, and should be considered as the fuel of choice for eliminating the dependency on petroleum. DME can be used as a clean high-efficiency compression ignition fuel with reduced NO x, SO x, and particulate matter, it can be efficiently reformed to hydrogen at low temperatures, and does not have large issues with toxicity, production, infrastructure, and transportation as do various other fuels. The literature relevant to DME use is reviewed and summarized to demonstrate the viability of DME as an alternative fuel.

Factors influencing fire behaviour in shrublands of different stand ages and the implications for using prescribed burning to reduce wildfire risk.

PubMed

Baeza, M J; De Luís, M; Raventós, J; Escarré, A

2002-06-01

Fire behaviour under experimental conditions is described in nine Mediterranean gorse shrublands ranging from 3-12 years of age with different fuel loads. Significant differences in the fire-line intensity, fuel load and rate of fire spread have been found to be related to the stage of development of the communities. Fire spread is correlated with fuel moisture using multiple regression techniques. Differences in fuel moisture between mature and young communities under moderate weather conditions have been found. The lower moisture content identified in the mature shrubland is due both to the decreasing moisture content of senescent shrubland in some species, mainly in live fractions of Ulex parviflorus Pour. fuel, and to a substantial increase in dead fuel fractions with low percentages of moisture content. The result is that the older the shrubland is, the greater will be the decrease in the total moisture content of the vegetation. In these moderate weather conditions, the fire intensity of the mature community was as high as the maximum intensity recommended for prescribed fires. This fact seems to indicate that, even under moderate conditions, prescribed burning as an alternative management tool in the mature shrubland must always take into account fuel control; on the other hand, this technique could be applied more easily when the shrubland is at an intermediate growth stage (4-5 years of age). Therefore, more frequent low-intensity prescribed fires are indicated to abate the risk of catastrophic fire.

The COPERNIC3 project: how AREVA is successfully developing an advanced global fuel rod performance code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garnier, Ch.; Mailhe, P.; Sontheimer, F.

2007-07-01

Fuel performance is a key factor for minimizing operating costs in nuclear plants. One of the important aspects of fuel performance is fuel rod design, based upon reliable tools able to verify the safety of current fuel solutions, prevent potential issues in new core managements and guide the invention of tomorrow's fuels. AREVA is developing its future global fuel rod code COPERNIC3, which is able to calculate the thermal-mechanical behavior of advanced fuel rods in nuclear plants. Some of the best practices to achieve this goal are described, by reviewing the three pillars of a fuel rod code: the database,more » the modelling and the computer and numerical aspects. At first, the COPERNIC3 database content is described, accompanied by the tools developed to effectively exploit the data. Then is given an overview of the main modelling aspects, by emphasizing the thermal, fission gas release and mechanical sub-models. In the last part, numerical solutions are detailed in order to increase the computational performance of the code, with a presentation of software configuration management solutions. (authors)« less

Can biofuels be a solution to climate change? The implications of land use change-related emissions for policy

PubMed Central

Khanna, Madhu; Crago, Christine L.; Black, Mairi

2011-01-01

Biofuels have gained increasing attention as an alternative to fossil fuels for several reasons, one of which is their potential to reduce the greenhouse gas (GHG) emissions from the transportation sector. Recent studies have questioned the validity of claims about the potential of biofuels to reduce GHG emissions relative to the liquid fossil fuels they are replacing when emissions owing to direct (DLUC) and indirect land use changes (ILUC) that accompany biofuels are included in the life cycle GHG intensity of biofuels. Studies estimate that the GHG emissions released from ILUC could more than offset the direct GHG savings by producing biofuels and replacing liquid fossil fuels and create a ‘carbon debt’ with a long payback period. The estimates of this payback period, however, vary widely across biofuels from different feedstocks and even for a single biofuel across different modelling assumptions. In the case of corn ethanol, this payback period is found to range from 15 to 200 years. We discuss the challenges in estimating the ILUC effect of a biofuel and differences across biofuels, and its sensitivity to the assumptions and policy scenarios considered by different economic models. We also discuss the implications of ILUC for designing policies that promote biofuels and seek to reduce GHG emissions. In a first-best setting, a global carbon tax is needed to set both DLUC and ILUC emissions to their optimal levels. However, it is unclear whether unilateral GHG mitigation policies, even if they penalize the ILUC-related emissions, would increase social welfare and lead to optimal emission levels. In the absence of a global carbon tax, incentivizing sustainable land use practices through certification standards, government regulations and market-based pressures may be a viable option for reducing ILUC. PMID:22482030

Can biofuels be a solution to climate change? The implications of land use change-related emissions for policy.

PubMed

Khanna, Madhu; Crago, Christine L; Black, Mairi

2011-04-06

Biofuels have gained increasing attention as an alternative to fossil fuels for several reasons, one of which is their potential to reduce the greenhouse gas (GHG) emissions from the transportation sector. Recent studies have questioned the validity of claims about the potential of biofuels to reduce GHG emissions relative to the liquid fossil fuels they are replacing when emissions owing to direct (DLUC) and indirect land use changes (ILUC) that accompany biofuels are included in the life cycle GHG intensity of biofuels. Studies estimate that the GHG emissions released from ILUC could more than offset the direct GHG savings by producing biofuels and replacing liquid fossil fuels and create a 'carbon debt' with a long payback period. The estimates of this payback period, however, vary widely across biofuels from different feedstocks and even for a single biofuel across different modelling assumptions. In the case of corn ethanol, this payback period is found to range from 15 to 200 years. We discuss the challenges in estimating the ILUC effect of a biofuel and differences across biofuels, and its sensitivity to the assumptions and policy scenarios considered by different economic models. We also discuss the implications of ILUC for designing policies that promote biofuels and seek to reduce GHG emissions. In a first-best setting, a global carbon tax is needed to set both DLUC and ILUC emissions to their optimal levels. However, it is unclear whether unilateral GHG mitigation policies, even if they penalize the ILUC-related emissions, would increase social welfare and lead to optimal emission levels. In the absence of a global carbon tax, incentivizing sustainable land use practices through certification standards, government regulations and market-based pressures may be a viable option for reducing ILUC.

Historic Patterns of CO{sub 2} Emissions from Fossil Fuels: Implications for Stabilization of Emissions

DOE R&D Accomplishments Database

Andres, R. J.; Marland, G.

1994-06-01

This paper examines the historical record of greenhouse gas emissions since 1950, reviews the prospects for emissions into the future, and projects what would be the short-term outcome if the stated targets of the FCCC were in fact achieved. The examination focuses on the most important of the greenhouse gases, CO{sub 2}. The extensive record of historic CO{sub 2} emissions is explored to ascertain if it is an adequate basis for useful extrapolation into the near future. Global carbon dioxide emissions from fossil fuel consumption have been documented. Emissions grew at 4.3% per year from 1950 until the time of the 1973 oil crisis. Another disruption in growth followed the oil price increases of 1979. Global total emissions have been increasing steadily since the 1982-1983 minimum and have grown by more than 20% since then. At present, emission Of CO{sub 2} from fossil fuel burning is dominated by a few countries: the U.S., the former Soviet Union, China, the developed countries of Europe and Japan. Only 20 countries emit 84% of emissions from all countries. However, rates of growth in many of the developed countries are now very low. In contrast, energy use has grown rapidly over the last 20 years in some of the large, developing economies. Emissions from fossil fuel consumption are now nearly 4 times those from land use change and are the primary cause of measured increases in the atmospheric concentration of CO{sub 2}. The increasing concentration of atmospheric CO{sub 2} has led to rising concern about the possibility of impending changes in the global climate system. In an effort to limit or mitigate potential negative effects of global climate change, 154 countries signed the United Nations Framework Convention on Climate Change (FCCC) in Rio de Janeiro in June, 1992. The FCCC asks all countries to conduct an inventory of their current greenhouse gas emissions setting non-binding targets.

Simulating the potential effects of plug-in hybrid electric vehicles on the energy budget and tax revenues for Onondaga County, New York

NASA Astrophysics Data System (ADS)

Balogh, Stephen B.

My objectives were to predict the energetic effects of a large increase in plug-in hybrid electric vehicles (PHEV) and their implications on fuel tax collections in Onondaga County. I examined two alternative taxation policies. To do so, I built a model of county energy consumption based on prorated state-level energy consumption data and census data. I used two scenarios to estimate energy consumption trends over the next 30 years and the effects of PHEV on energy use and fuel tax revenues. I found that PHEV can reduce county gasoline consumption, but they would curtail fuel tax revenues and increase residential electricity demand. A one-cent per VMT tax on PHEV users provides insufficient revenue to replace reduced fuel tax collection. A sales tax on electricity consumption generates sufficient replacement revenue at low PHEV market shares. However, at higher shares, the tax on electricity use would exceed the current county tax rate. Keywords: electricity, energy, gasoline, New York State, Onondaga County, plug-in hybrid electric vehicles, transportation model, tax policy

Water footprint of U.S. transportation fuels.

PubMed

Scown, Corinne D; Horvath, Arpad; McKone, Thomas E

2011-04-01

In the modern global economy, water and energy are fundamentally connected. Water already plays a major role in electricity generation and, with biofuels and electricity poised to gain a significant share of the transportation fuel market, water will become significantly more important for transportation energy as well. This research provides insight into the potential changes in water use resulting from increased biofuel or electricity production for transportation energy, as well as the greenhouse gas and freshwater implications. It is shown that when characterizing the water impact of transportation energy, incorporating indirect water use and defensible allocation techniques have a major impact on the final results, with anywhere between an 82% increase and a 250% decrease in the water footprint if evaporative losses from hydroelectric power are excluded. The greenhouse gas impact results indicate that placing cellulosic biorefineries in areas where water must be supplied using alternative means, such as desalination, wastewater recycling, or importation can increase the fuel's total greenhouse gas footprint by up to 47%. The results also show that the production of ethanol and petroleum fuels burden already overpumped aquifers, whereas electricity production is far less dependent on groundwater.

Implications of ``peak oil'' for atmospheric CO2 and climate

NASA Astrophysics Data System (ADS)

Kharecha, Pushker A.; Hansen, James E.

2008-09-01

Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming. The amounts of "proven" and potential fossil fuel reserves are uncertain and debated. Regardless of the true values, society has flexibility in the degree to which it chooses to exploit these reserves, especially unconventional fossil fuels and those located in extreme or pristine environments. If conventional oil production peaks within the next few decades, it may have a large effect on future atmospheric CO2 and climate change, depending upon subsequent energy choices. Assuming that proven oil and gas reserves do not greatly exceed estimates of the Energy Information Administration, and recent trends are toward lower estimates, we show that it is feasible to keep atmospheric CO2 from exceeding about 450 ppm by 2100, provided that emissions from coal, unconventional fossil fuels, and land use are constrained. Coal-fired power plants without sequestration must be phased out before midcentury to achieve this CO2 limit. It is also important to "stretch" conventional oil reserves via energy conservation and efficiency, thus averting strong pressures to extract liquid fuels from coal or unconventional fossil fuels while clean technologies are being developed for the era "beyond fossil fuels". We argue that a rising price on carbon emissions is needed to discourage conversion of the vast fossil resources into usable reserves, and to keep CO2 beneath the 450 ppm ceiling.

Hige Compression Ratio Turbo Gasoline Engine Operation Using Alcohol Enhancement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heywood, John; Jo, Young Suk; Lewis, Raymond

The overall objective of this project was to quantify the potential for improving the performance and efficiency of gasoline engine technology by use of alcohols to suppress knock. Knock-free operation is obtained by direct injection of a second “anti-knock” fuel such as ethanol, which suppresses knock when, with gasoline fuel, knock would occur. Suppressing knock enables increased turbocharging, engine downsizing, and use of higher compression ratios throughout the engine’s operating map. This project combined engine testing and simulation to define knock onset conditions, with different mixtures of gasoline and alcohol, and with this information quantify the potential for improving themore » efficiency of turbocharged gasoline spark-ignition engines, and the on-vehicle fuel consumption reductions that could then be realized. The more focused objectives of this project were therefore to: Determine engine efficiency with aggressive turbocharging and downsizing and high compression ratio (up to a compression ratio of 13.5:1) over the engine’s operating range; Determine the knock limits of a turbocharged and downsized engine as a function of engine speed and load; Determine the amount of the knock-suppressing alcohol fuel consumed, through the use of various alcohol-gasoline and alcohol-water gasoline blends, for different driving cycles, relative to the gasoline consumed; Determine implications of using alcohol-boosted engines, with their higher efficiency operation, in both light-duty and medium-duty vehicle sectors.« less

Life cycle economic and environmental implications of using nanocomposites in automobiles.

PubMed

Lloyd, Shannon M; Lave, Lester B

2003-08-01

By reducing the energy and materials required to provide goods and services, nanotechnology has the potential to provide more appealing products while improving environmental performance and sustainability. Whether and how soon this potential could be realized depends on phrasing the right research and development (R&D) questions and pursuing commercialization intelligently. A sufficiently broad perspective at the outset is required to understand economic and technical feasibility, estimate life cycle environmental implications, and minimize unanticipated negative impacts. The rapid rise in federally funded nanotechnology R&D dictates that consideration of societal benefits will have a large role in setting the R&D agenda. We estimate potential selected economic and environmental impacts associated with the use of nanotechnology in the automotive industry. In particular, we project the material processing and fuel economy benefits associated with using a clay-polypropylene nanocomposite instead of steel or aluminum in light-duty vehicle body panels. Although the manufacturing cost is currently higher, a life cycle analysis shows potential benefits in reducing energy use and environment discharges by using a nanocomposite design.

Projected Growth in Small-Scale, Fossil-Fueled Distributed Generation: Potential Implications for the U.S. Greenhouse Gas Inventory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eberle, Annika; Heath, Garvin A

The generation capacity of small-scale (less than one megawatt) fossil-fueled electricity in the United States is anticipated to grow by threefold to twenty-fold from 2015 to 2040. However, in adherence with internationally agreed upon carbon accounting methods, the Environmental Protection Agency's (EPA's) U.S. Greenhouse Inventory (GHGI) does not currently attribute greenhouse gases (GHGs) from these small-scale distributed generation sources to the electric power sector and instead accounts for these emissions in the sector that uses the distributed generation (e.g., the commercial sector). In addition, no other federal electric-sector GHG emission data product produced by the EPA or the U.S. Energymore » Information Administration (EIA) can attribute these emissions to electricity. We reviewed the technical documentation for eight federal electric-sector GHG emission data products, interviewed the data product owners, collected their GHG emission estimates, and analyzed projections for growth in fossil-fueled distributed generation. We show that, by 2040, these small-scale generators could account for at least about 1%- 5% of total CO2 emissions from the U.S. electric power sector. If these emissions fall outside the electric power sector, the United States may not be able to completely and accurately track changes in electricity-related CO2 emissions, which could impact how the country sets GHG reduction targets and allocates mitigation resources. Because small-scale, fossil-fueled distributed generation is expected to grow in other countries as well, the results of this work also have implications for global carbon accounting.« less

Technical and economic feasibility of alternative fuel use in process heaters and small boilers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1980-02-01

The technical and economic feasibility of using alternate fuels - fuels other than oil and natural gas - in combustors not regulated by the Powerplant and Industrial Fuel Use Act of 1978 (FUA) was evaluated. FUA requires coal or alternate fuel use in most large new boilers and in some existing boilers. Section 747 of FUA authorizes a study of the potential for reduced oil and gas use in combustors not subject to the act: small industrial boilers with capacities less than 100 MMBtu/hr, and process heat applications. Alternative fuel use in combustors not regulated by FUA was examined andmore » the impact of several measures to encourage the substitution of alternative fuels in these combustors was analyzed. The primary processes in which significant fuel savings can be achieved are identified. Since feedstock uses of oil and natural gas are considered raw materials, not fuels, feedstock applications are not examined in this analysis. The combustors evaluated in this study comprise approximately 45% of the fuel demand projected in 1990. These uses would account for more than 3.5 million barrels per day equivalent fuel demand in 1990.« less

Implications of the spatial dynamics of fire spread for the bistability of savanna and forest.

PubMed

Schertzer, E; Staver, A C; Levin, S A

2015-01-01

The role of fire in expanding the global distribution of savanna is well recognized. Empirical observations and modeling suggest that fire spread has a threshold response to fuel-layer continuity, which sets up a positive feedback that maintains savanna-forest bistability. However, modeling has so far failed to examine fire spread as a spatial process that interacts with vegetation. Here, we use simple, well-supported assumptions about fire spread as an infection process and its effects on trees to ask whether spatial dynamics qualitatively change the potential for savanna-forest bistability. We show that the spatial effects of fire spread are the fundamental reason that bistability is possible: because fire spread is an infection process, it exhibits a threshold response to fuel continuity followed by a rapid increase in fire size. Other ecological processes affecting fire spread may also contribute including temporal variability in demography or fire spread. Finally, including the potential for spatial aggregation increases the potential both for savanna-forest bistability and for savanna and forest to coexist in a landscape mosaic.

Environmental implications of iron fuel borne catalysts and their effects on diesel particulate formation and composition

EPA Science Inventory

Metal fuel borne catalysts can be used with diesel fuels to effectively reduce engine out particle mass emissions. Mixed with the fuel, the metals become incorporated as nanometer-scale occlusions with soot during its formation and are available to promote in-cylinder soot oxida...

Nanostructure enzyme assemblies for biomass conversion

USDA-ARS?s Scientific Manuscript database

Biomass represents a vast resource for production of the world’s fuel and chemical feedstock needs. The use of enzymes to effect these bioconversions offers an alternative that is potentially more specific and environmentally-friendly than harsher chemical methodologies. Some species of anaerobic ...

The challenges and opportunities for integration of solar syngas production with liquid fuel synthesis

NASA Astrophysics Data System (ADS)

Hinkley, James T.; McNaughton, Robbie K.; Pye, John; Saw, Woei; Stechel, Ellen B.

2016-05-01

Reforming of methane is practiced on a vast scale globally for the production of syngas as a precursor for the production of many commodities, including hydrogen, ammonia and synthetic liquid fuels. Solar reforming can reduce the greenhouse gas intensity of syngas production by up to about 40% by using solar thermal energy to provide the endothermic heat of reaction, traditionally supplied by combustion of some of the feed. This has the potential to enable the production of solar derived synthetic fuels as drop in replacements for conventional fuels with significantly lower CO2 intensity than conventional gas to liquids (GTL) processes. However, the intermittent nature of the solar resource - both diurnal and seasonal - poses significant challenges for such a concept, which relies on synthesis processes that typically run continuously on very stable feed compositions. We find that the integration of solar syngas production to a GTL process is a non-trivial exercise, with the ability to turn down the capacity of the GTL synthesis section, and indeed to suspend operations for short periods without significant detriment to product quality or process operability, likely to be a key driver for the commercial implementation of solar liquid fuels. Projected costs for liquid fuel synthesis suggest that solar reforming and small scale gas to liquid synthesis can potentially compete with conventional oil derived transport fuels in the short to medium term.

Modeling and optimization of a typical fuel cell-heat engine hybrid system and its parametric design criteria

NASA Astrophysics Data System (ADS)

Zhao, Yingru; Chen, Jincan

A theoretical modeling approach is presented, which describes the behavior of a typical fuel cell-heat engine hybrid system in steady-state operating condition based on an existing solid oxide fuel cell model, to provide useful fundamental design characteristics as well as potential critical problems. The different sources of irreversible losses, such as the electrochemical reaction, electric resistances, finite-rate heat transfer between the fuel cell and the heat engine, and heat-leak from the fuel cell to the environment are specified and investigated. Energy and entropy analyses are used to indicate the multi-irreversible losses and to assess the work potentials of the hybrid system. Expressions for the power output and efficiency of the hybrid system are derived and the performance characteristics of the system are presented and discussed in detail. The effects of the design parameters and operating conditions on the system performance are studied numerically. It is found that there exist certain optimum criteria for some important parameters. The results obtained here may provide a theoretical basis for both the optimal design and operation of real fuel cell-heat engine hybrid systems. This new approach can be easily extended to other fuel cell hybrid systems to develop irreversible models suitable for the investigation and optimization of similar energy conversion settings and electrochemistry systems.

Hybrid Vehicle Technologies and their potential for reducing oil use

NASA Astrophysics Data System (ADS)

German, John

2006-04-01

Vehicles with hybrid gasoline-electric powertrains are starting to gain market share. Current hybrid vehicles add an electric motor, battery pack, and power electronics to the conventional powertrain. A variety of engine/motor configurations are possible, each with advantages and disadvantages. In general, efficiency is improved due to engine shut-off at idle, capture of energy during deceleration that is normally lost as heat in the brakes, downsizing of the conventional engine, and, in some cases, propulsion on the electric motor alone. Ongoing increases in hybrid market share are dependent on cost reduction, especially the battery pack, efficiency synergies with other vehicle technologies, use of the high electric power to provide features desired by customers, and future fuel price and availability. Potential barriers include historically low fuel prices, high discounting of the fuel savings by new vehicle purchasers, competing technologies, and tradeoffs with other factors desired by customers, such as performance, utility, safety, and luxury features.

Hydrogen production from algal biomass - Advances, challenges and prospects.

PubMed

Show, Kuan-Yeow; Yan, Yuegen; Ling, Ming; Ye, Guoxiang; Li, Ting; Lee, Duu-Jong

2018-06-01

Extensive effort is being made to explore renewable energy in replacing fossil fuels. Biohydrogen is a promising future fuel because of its clean and high energy content. A challenging issue in establishing hydrogen economy is sustainability. Biohydrogen has the potential for renewable biofuel, and could replace current hydrogen production through fossil fuel thermo-chemical processes. A promising source of biohydrogen is conversion from algal biomass, which is abundant, clean and renewable. Unlike other well-developed biofuels such as bioethanol and biodiesel, production of hydrogen from algal biomass is still in the early stage of development. There are a variety of technologies for algal hydrogen production, and some laboratory- and pilot-scale systems have demonstrated a good potential for full-scale implementation. This work presents an elucidation on development in biohydrogen encompassing biological pathways, bioreactor designs and operation and techno-economic evaluation. Challenges and prospects of biohydrogen production are also outlined. Copyright © 2018 Elsevier Ltd. All rights reserved.

Climate Change Implications to the Global Security Environment, U.S. Interests, and Future Naval Operations

DTIC Science & Technology

2011-03-14

humanitarian and disaster relief operations, which the Navy increasingly is called upon to respond. In my research, I found that the U.S. Gover ;unent...dependent upon tourism will be affected disproportionately economically. A country’s political. climate can quickly and drastically change in a health... tourism , and the potential fuel savings for commercial shipping by transiting the Northern Sea during ice-free conditions make the Arctic particularly

Innovative Approaches to Fuel-Air Mixing and Combustion in Airbreathing Hypersonic Engines

NASA Astrophysics Data System (ADS)

MacLeod, C.

This paper describes some innovative methods for achieving enhanced fuel-air mixing and combustion in Scramjet-like spaceplane engines. A multimodal approach to the problem is discussed; this involves using several concurrent methods of forced mixing. The paper concentrates on Electromagnetic Activation (EMA) and Electrostatic Attraction as suitable techniques for this purpose - although several other potential methods are also discussed. Previously published empirical data is used to draw conclusions about the likely effectiveness of the system and possible engine topologies are outlined.

Review of betavoltaic energy conversion

NASA Astrophysics Data System (ADS)

Olsen, Larry C.

1993-05-01

Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for fabricating Pm-147 fueled batteries by the author in the early 1970's is reviewed. Finally, the potential performance of advanced betavoltaic power sources is considered.

Review of betavoltaic energy conversion

NASA Technical Reports Server (NTRS)

Olsen, Larry C.

1993-01-01

Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for fabricating Pm-147 fueled batteries by the author in the early 1970's is reviewed. Finally, the potential performance of advanced betavoltaic power sources is considered.

Review of Jet Fuel Life Cycle Assessment Methods and Sustainability Metrics

DOT National Transportation Integrated Search

2015-12-01

The primary aim of this study is to help aviation jet fuel purchasers (primarily commercial airlines and the U.S. military) to understand the sustainability implications of their jet fuel purchases and provide guidelines for procuring sustainable fue...

The Fukushima Nuclear Event and its Implications for Nuclear Power

NASA Astrophysics Data System (ADS)

Golay, Michael

2011-11-01

The combined strong earthquake and super tsunami of 12 March 2011 at the Fukushima nuclear power plant imposed the most severe challenges ever experienced at such a facility. Information regarding the plant response and status remains uncertain, but it is clear that severe damage has been sustained, that the plant staff have responded creatively and that the offsite implications are unlikely to be seriously threatening to the health, if not the prosperity, of the surrounding population. Reexamination of the regulatory constraints of nuclear power will occur worldwide, and some changes are likely; particularly concerning reliance upon active systems for achieving critical safety functions and concerning treatments of used reactor fuel. Whether worldwide expansion of the nuclear power economy will be slowed in the long run is perhaps unlikely and worth discussion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardiner, D. P.; Bardon, M. F.; Clark, W.

This study assessed differences in headspace flammability for summertime gasolines and new high-ethanol content fuel blends. The results apply to vehicle fuel tanks and underground storage tanks. Ambient temperature and fuel formulation effects on headspace vapor flammability of ethanol/gasoline blends were evaluated. Depending on the degree of tank filling, fuel type, and ambient temperature, fuel vapors in a tank can be flammable or non-flammable. Pure gasoline vapors in tanks generally are too rich to be flammable unless ambient temperatures are extremely low. High percentages of ethanol blended with gasoline can be less volatile than pure gasoline and can produce flammablemore » headspace vapors at common ambient temperatures. The study supports refinements of fuel ethanol volatility specifications and shows potential consequences of using noncompliant fuels. E85 is flammable at low temperatures; denatured ethanol is flammable at warmer temperatures. If both are stored at the same location, one or both of the tanks' headspace vapors will be flammable over a wide range of ambient temperatures. This is relevant to allowing consumers to splash -blend ethanol and gasoline at fueling stations. Fuels compliant with ASTM volatility specifications are relatively safe, but the E85 samples tested indicate that some ethanol fuels may produce flammable vapors.« less

Fuel Sustainability And Actinide Production Of Doping Minor Actinide In Water-Cooled Thorium Reactor

NASA Astrophysics Data System (ADS)

Permana, Sidik

2017-07-01

Fuel sustainability of nuclear energy is coming from an optimum fuel utilization of the reactor and fuel breeding program. Fuel cycle option becomes more important for fuel cycle utilization as well as fuel sustainability capability of the reactor. One of the important issues for recycle fuel option is nuclear proliferation resistance issue due to production plutonium. To reduce the proliferation resistance level, some barriers were used such as matrial barrier of nuclear fuel based on isotopic composition of even mass number of plutonium isotope. Analysis on nuclear fuel sustainability and actinide production composition based on water-cooled thorium reactor system has been done and all actinide composition are recycled into the reactor as a basic fuel cycle scheme. Some important parameters are evaluated such as doping composition of minor actinide (MA) and volume ratio of moderator to fuel (MFR). Some feasible parameters of breeding gains have been obtained by additional MA doping and some less moderation to fuel ratios (MFR). The system shows that plutonium and MA are obtained low compositions and it obtains some higher productions of even mass plutonium, which is mainly Pu-238 composition, as a control material to protect plutonium to be used as explosive devices.

End product yields from the extraruminal fermentation of various polysaccharide, protein and nucleic acid components of biofuels feedstocks.

PubMed

Weimer, Paul J

2011-02-01

"Extraruminal" fermentations employing in vitro incubation of mixed ruminal bacterial consortia, are capable of converting a complex array of biomass materials to mixtures of volatile fatty acids (VFA), methane, and carbon dioxide. Most of the potential energy in the biomass feedstock is retained in the VFA products, which are potential reactants for electrochemical conversion to hydrocarbon fuels. Quantitative data on VFA yields and proportions from biomass components are necessary for determining industrial feasibility, but such measurements have not been systematically reported. VFA yields and proportions were determined for a variety of carbohydrates, proteins and nucleic acids. Carbohydrates yielded primarily acetic and propionic acids, while proteins also yielded a more favorable product mix (longer average chain length and branched chain VFAs). Addition of certain co-substrates (e.g., glycerol) favorably improved the VFA product mix. The results have implications for hydrocarbon fuel generation from biomass materials by hybrid fermentation/chemical processes. Published by Elsevier Ltd.

Hydrogen and advanced aerospace materials

NASA Technical Reports Server (NTRS)

Nelson, Howard G.

1988-01-01

The hydrogen embrittlement is briefly reviewed and discussed in terms of specific structural materials considered for use on a generic, hydrogen-fueled, hypersonic aerospace vehicle. A few unusual hydrogen-material incompatibility concerns are identified and some solution methodologies are discussed that could potentially lessen these concerns.

High-resolution observations of combustion in heterogeneous surface fuels

Treesearch

E. Louise Loudermilk; Gary L. Achtemeier; Joseph J. O' Brien; J. Kevin Hiers; Benjamin S. Hornsby

2014-01-01

In ecosystems with frequent surface fires, fire and fuel heterogeneity at relevant scales have been largely ignored. This could be because complete burns give an impression of homogeneity, or due to the difficulty in capturing fine-scale variation in fuel characteristics and fire behaviour. Fire movement between patches of fuel can have implications for modelling fire...

Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

NASA Astrophysics Data System (ADS)

Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

2011-11-01

Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

Thermodynamic analysis of biofuels as fuels for high temperature fuel cells

NASA Astrophysics Data System (ADS)

Milewski, Jarosław; Bujalski, Wojciech; Lewandowski, Janusz

2013-02-01

Based on mathematical modeling and numerical simulations, applicativity of various biofuels on high temperature fuel cell performance are presented. Governing equations of high temperature fuel cell modeling are given. Adequate simulators of both solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) have been done and described. Performance of these fuel cells with different biofuels is shown. Some characteristics are given and described. Advantages and disadvantages of various biofuels from the system performance point of view are pointed out. An analysis of various biofuels as potential fuels for SOFC and MCFC is presented. The results are compared with both methane and hydrogen as the reference fuels. The biofuels are characterized by both lower efficiency and lower fuel utilization factors compared with methane. The presented results are based on a 0D mathematical model in the design point calculation. The governing equations of the model are also presented. Technical and financial analysis of high temperature fuel cells (SOFC and MCFC) are shown. High temperature fuel cells can be fed by biofuels like: biogas, bioethanol, and biomethanol. Operational costs and possible incomes of those installation types were estimated and analyzed. A comparison against classic power generation units is shown. A basic indicator net present value (NPV) for projects was estimated and commented.

Elevated production of NH4NO3 from the photochemical processing of vehicle exhaust: Implications for air quality in the Seoul Metropolitan Region

NASA Astrophysics Data System (ADS)

Link, Michael F.; Kim, Jounghwa; Park, Gyutae; Lee, Taehyoung; Park, Taehyun; Babar, Zaeem Bin; Sung, Kijae; Kim, Pilho; Kang, Seokwon; Kim, Jeong Soo; Choi, Yongjoo; Son, Jihawn; Lim, Ho-Jin; Farmer, Delphine K.

2017-05-01

A vehicle fleet representative of passenger vehicles driven in the Seoul Metropolitan Region was investigated for primary emissions and secondary chemistry. Exhaust was photochemically oxidized in a flow reactor to determine the ammonium nitrate (NH4NO3) aerosol formation potential from vehicles of gasoline, diesel and liquid petroleum gasoline (LPG) fuel types. Secondary formation of aerosol NH4NO3, was larger than primary emissions for all vehicle fuel types except diesel, for which negligible secondary NH4NO3 production was observed. Although diesel vehicles emitted more primary nitrogen oxides than other vehicle types, ammonia emitted from gasoline and liquid petroleum gasoline fuels types limited the secondary production of NH4NO3. The results suggest that gasoline and liquid petroleum gasoline vehicles with three-way catalysts could be an important source of ammonia for NH4NO3 aerosol formation in ammonia-limited environments, including the Seoul Metropolitan Region.

Survey of US fuel ethanol plants.

PubMed

Saunders, J A; Rosentrater, K A

2009-07-01

The ethanol industry is growing in response to increased consumer demands for fuel as well as the renewable fuel standard. Corn ethanol processing creates the following products: 1/3 ethanol, 1/3 distillers grains, and 1/3 carbon dioxide. As the production of ethanol increases so does the generation of its coproducts, and viable uses continually need to be developed. A survey was mailed to operational US ethanol plants to determine current practices. It inquired about processes, equipment used, end products, and desired future directions for coproducts. Results indicated that approximately one-third of plant managers surveyed expressed a willingness to alter current drying time and temperature if it could result in a higher quality coproduct. Other managers indicated hesitation, based on lack of economic incentives, potential cost and return, and capital required. Respondents also reported the desire to use their coproducts in some of the following products: fuels, extrusion, pellets, plastics, and human food applications. These results provide a snapshot of the industry, and indicate that operational changes to the current production of DDGS must be based upon the potential for positive economic returns.

Irradiation behavior of the interaction product of U-Mo fuel particle dispersion in an Al matrix

NASA Astrophysics Data System (ADS)

Kim, Yeon Soo; Hofman, G. L.

2012-06-01

Irradiation performance of U-Mo fuel particles dispersed in Al matrix is stable in terms of fuel swelling and is suitable for the conversion of research and test reactors from highly enriched uranium (HEU) to low enriched uranium (LEU). However, tests of the fuel at high temperatures and high burnups revealed obstacles caused by the interaction layers forming between the fuel particle and matrix. In some cases, fission gas filled pores grow and interconnect in the interdiffusion layer resulting in fuel plate failure. Postirradiation observations are made to examine the behavior of the interdiffusion layers. The interdiffusion layers show a fluid-like behavior characteristic of amorphous materials. In the amorphous interdiffusion layers, fission gas diffusivity is high and the material viscosity is low so that the fission gas pores readily form and grow. Based on the observations, a pore formation mechanism is proposed and potential remedies to suppress the pore growth are also introduced.

Polluted Pathways: Mechanisms of Metabolic Disruption by Endocrine Disrupting Chemicals.

PubMed

Mimoto, Mizuho S; Nadal, Angel; Sargis, Robert M

2017-06-01

Environmental toxicants are increasingly implicated in the global decline in metabolic health. Focusing on diabetes, herein, the molecular and cellular mechanisms by which metabolism disrupting chemicals (MDCs) impair energy homeostasis are discussed. Emerging data implicate MDC perturbations in a variety of pathways as contributors to metabolic disease pathogenesis, with effects in diverse tissues regulating fuel utilization. Potentiation of traditional metabolic risk factors, such as caloric excess, and emerging threats to metabolism, such as disruptions in circadian rhythms, are important areas of current and future MDC research. Increasing evidence also implicates deleterious effects of MDCs on metabolic programming that occur during vulnerable developmental windows, such as in utero and early post-natal life as well as pregnancy. Recent insights into the mechanisms by which MDCs alter energy homeostasis will advance the field's ability to predict interactions with classical metabolic disease risk factors and empower studies utilizing targeted therapeutics to treat MDC-mediated diabetes.

Making the Surface Fleet Green: The DOTMLPF, Policy, and Cost Implications of Using Biofuel in Surface Ships

DTIC Science & Technology

2012-12-01

Navy’s Ships Renewable Fuels Evaluation, 2011) ..25 Table 4. Diesel Injector Component Testing (From U.S. Navy Biofuel Test and Qualification Update...components, including shipboard quality assurance instruments, fuel injector nozzles , fuel nozzle atomization, fuel nozzle fouling, carbon deposition...Leung, Turgeon, & Williams, 2011, p. 7). Table 4 lists the results from component testing conducted on various diesel engine fuel injectors using

Electrocatalysis of borohydride oxidation: a review of density functional theory approach combined with experimental validation.

PubMed

Escaño, Mary Clare Sison; Arevalo, Ryan Lacdao; Gyenge, Elod; Kasai, Hideaki

2014-09-03

The electrocatalysis of borohydride oxidation is a complex, up-to-eight-electron transfer process, which is essential for development of efficient direct borohydride fuel cells. Here we review the progress achieved by density functional theory (DFT) calculations in explaining the adsorption of BH4(-) on various catalyst surfaces, with implications for electrocatalyst screening and selection. Wherever possible, we correlate the theoretical predictions with experimental findings, in order to validate the proposed models and to identify potential directions for further advancements.

Electrocatalysis of borohydride oxidation: a review of density functional theory approach combined with experimental validation

NASA Astrophysics Data System (ADS)

Sison Escaño, Mary Clare; Lacdao Arevalo, Ryan; Gyenge, Elod; Kasai, Hideaki

2014-09-01

The electrocatalysis of borohydride oxidation is a complex, up-to-eight-electron transfer process, which is essential for development of efficient direct borohydride fuel cells. Here we review the progress achieved by density functional theory (DFT) calculations in explaining the adsorption of BH4- on various catalyst surfaces, with implications for electrocatalyst screening and selection. Wherever possible, we correlate the theoretical predictions with experimental findings, in order to validate the proposed models and to identify potential directions for further advancements.

Microstructural Characterization of a Mg Matrix U-Mo Dispersion Fuel Plate Irradiated in the Advanced Test Reactor to High Fission Density: SEM Results

NASA Astrophysics Data System (ADS)

Keiser, Dennis D.; Jue, Jan-Fong; Miller, Brandon D.; Gan, Jian; Robinson, Adam B.; Medvedev, Pavel G.; Madden, James W.; Moore, Glenn A.

2016-06-01

Low-enriched (U-235 <20 pct) U-Mo dispersion fuel is being developed for use in research and test reactors. In most cases, fuel plates with Al or Al-Si alloy matrices have been tested in the Advanced Test Reactor to support this development. In addition, fuel plates with Mg as the matrix have also been tested. The benefit of using Mg as the matrix is that it potentially will not chemically interact with the U-Mo fuel particles during fabrication or irradiation, whereas with Al and Al-Si alloys such interactions will occur. Fuel plate R9R010 is a Mg matrix fuel plate that was aggressively irradiated in ATR. This fuel plate was irradiated as part of the RERTR-8 experiment at high temperature, high fission rate, and high power, up to high fission density. This paper describes the results of the scanning electron microscopy (SEM) analysis of an irradiated fuel plate using polished samples and those produced with a focused ion beam. A follow-up paper will discuss the results of transmission electron microscopy (TEM) analysis. Using SEM, it was observed that even at very aggressive irradiation conditions, negligible chemical interaction occurred between the irradiated U-7Mo fuel particles and Mg matrix; no interconnection of fission gas bubbles from fuel particle to fuel particle was observed; the interconnected fission gas bubbles that were observed in the irradiated U-7Mo particles resulted in some transport of solid fission products to the U-7Mo/Mg interface; the presence of microstructural pathways in some U-9.1 Mo particles that could allow for transport of fission gases did not result in the apparent presence of large porosity at the U-7Mo/Mg interface; and, the Mg-Al interaction layers that were present at the Mg matrix/Al 6061 cladding interface exhibited good radiation stability, i.e. no large pores.

Logistics and operations implications of manual control of spacecraft docking maneuvers

NASA Technical Reports Server (NTRS)

Brody, Adam R.; Ellis, Stephen R.

1991-01-01

The implications of logistics and operations on the manual control of spacecraft docking are discussed. The results of simulation studies to investigate fuel and time cost tradeoffs are reviewed and discussed. Comparisons of acceleration control and pulse control are presented to evaluate the effects of astronauts being instructed to use pulse mode for fuel conservation. The applications of the findings to moon and Mars missions are addressed.

Fuel Cycle Performance of Thermal Spectrum Small Modular Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Worrall, Andrew; Todosow, Michael

2016-01-01

Small modular reactors may offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of small modular reactors on the nuclear fuel cycle and fuel cycle performance. The focus of this paper is on the fuel cycle impacts of light water small modular reactors in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy Office of Nuclear Energy Fuel Cycle Options Campaign. Challenges with small modular reactors include:more » increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burn-up in the reactor and the fuel cycle performance. This paper summarizes the results of an expert elicitation focused on developing a list of the factors relevant to small modular reactor fuel, core, and operation that will impact fuel cycle performance. Preliminary scoping analyses were performed using a regulatory-grade reactor core simulator. The hypothetical light water small modular reactor considered in these preliminary scoping studies is a cartridge type one-batch core with 4.9% enrichment. Some core parameters, such as the size of the reactor and general assembly layout, are similar to an example small modular reactor concept from industry. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burn-up of the reactor. Fuel cycle performance metrics for a small modular reactor are compared to a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. Metrics performance for a small modular reactor are degraded for mass of spent nuclear fuel and high level waste disposed, mass of depleted uranium disposed, land use per energy generated, and carbon emission per energy generated« less

Screening of advanced cladding materials and UN-U3Si5 fuel

NASA Astrophysics Data System (ADS)

Brown, Nicholas R.; Todosow, Michael; Cuadra, Arantxa

2015-07-01

In the aftermath of Fukushima, a focus of the DOE-NE Advanced Fuels Campaign has been the development of advanced nuclear fuel and cladding options with the potential for improved performance in an accident. Uranium dioxide (UO2) fuels with various advanced cladding materials were analyzed to provide a reference for cladding performance impacts. For advanced cladding options with UO2 fuel, most of the cladding materials have some reactivity and discharge burn-up penalty (in GWd/t). Silicon carbide is one exception in that the reactor physics performance is predicted to be very similar to zirconium alloy cladding. Most candidate claddings performed similar to UO2-Zr fuel-cladding in terms of safety coefficients. The clear exception is that Mo-based materials were identified as potentially challenging from a reactor physics perspective due to high resonance absorption. This paper also includes evaluation of UN-U3Si5 fuels with Kanthal AF or APMT cladding. The objective of the U3Si5 phase in the UN-U3Si5 fuel concept is to shield the nitride phase from water. It was shown that UN-U3Si5 fuels with Kanthal AF or APMT cladding have similar reactor physics and fuel management performance over a wide parameter space of phase fractions when compared to UO2-Zr fuel-cladding. There will be a marginal penalty in discharge burn-up (in GWd/t) and the sensitivity to 14N content in UN ceramic composites is high. Analysis of the rim effect due to self-shielding in the fuel shows that the UN-based ceramic fuels are not expected to have significantly different relative burn-up distributions at discharge relative to the UO2 reference fuel. However, the overall harder spectrum in the UN ceramic composite fuels increases transuranic build-up, which will increase long-term activity in a once-thru fuel cycle but is expected to be a significant advantage in a fuel cycle with continuous recycling of transuranic material. It is recognized that the fuel and cladding properties assumed in these assessments are preliminary, and that additional data are necessary for these materials, most significantly under irradiation.

Investigation into the Implications of Fuel Cell Shipboard Integration into the T-AGOS 19 Class

DTIC Science & Technology

2012-02-01

with each defined by its fundamental electrolyte: i. Alkali Fuel Cells (AFC) ii. Polymer Exchange Membrane ( PEM ) iii. Phosphoric Acid Fuel Cells ...of the PEM family (High Temperature – HTPEM and Direct Methanol Fuel Cells – DMFC) were assessed against a range of basic ship requirements...of Stationary PEM Fuel Cell Systems”, DOE hydrogen program 2010 annual report. [11] US Energy Information Administration, “EIA - Weekly Retail

Wind Energy Deployment in Isolated Islanded Power Systems: Challenges & Realities (Poster)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baring-Gould, I.

Rising costs of fuels, energy surety, and the carbon impacts of diesel fuel are driving remote and islanded communities dependent on diesel power generation to look for alternatives. Over the past few years, interest in using wind energy to reduce diesel fuel consumption has increased dramatically, potentially providing economic, environmental, social, and security benefits to the energy supply of isolated and islanded communities. However, the task of implementing such systems has remained elusive and subject to many cases of lower-than-expected performance. This poster describes the current status of integrating higher contribution wind technology into islanded power systems, the progress ofmore » recent initiatives implemented by the U.S. Department of Energy and Interior, and some of the lingering technical and commercial challenges. Operating experience from a number of power systems is described. The worldwide market for wind development in islanded communities (some of these supplying large domestic loads) provides a strong market niche for the wind industry, even in the midst of a slow global recovery.« less

Survey of advanced nuclear technologies for potential applications of sonoprocessing.

PubMed

Rubio, Floren; Blandford, Edward D; Bond, Leonard J

2016-09-01

Ultrasonics has been used in many industrial applications for both sensing at low power and processing at higher power. Generally, the high power applications fall within the categories of liquid stream degassing, impurity separation, and sonochemical enhancement of chemical processes. Examples of such industrial applications include metal production, food processing, chemical production, and pharmaceutical production. There are many nuclear process streams that have similar physical and chemical processes to those applications listed above. These nuclear processes could potentially benefit from the use of high-power ultrasonics. There are also potential benefits to applying these techniques in advanced nuclear fuel cycle processes, and these benefits have not been fully investigated. Currently the dominant use of ultrasonic technology in the nuclear industry has been using low power ultrasonics for non-destructive testing/evaluation (NDT/NDE), where it is primarily used for inspections and for characterizing material degradation. Because there has been very little consideration given to how sonoprocessing can potentially improve efficiency and add value to important process streams throughout the nuclear fuel cycle, there are numerous opportunities for improvement in current and future nuclear technologies. In this paper, the relevant fundamental theory underlying sonoprocessing is highlighted, and some potential applications to advanced nuclear technologies throughout the nuclear fuel cycle are discussed. Copyright © 2016 Elsevier B.V. All rights reserved.

Preliminary Estimates of the Potential for Carbon Mitigation in European Soils Through No-Till Farming

DOE Data Explorer

Smith, P. [University of Aberdeen, Aberdeen, UK; Powlson, D. [University of Aberdeen, Aberdeen, UK; Glendining, M. [University of Aberdeen, Aberdeen, UK; Smith, J. [University of Aberdeen, Aberdeen, UK

2003-01-01

in this paper we estimate the European potential for carbon mitigation of no-till farming using results from European tillage experiments. Our calculations suggest some potential in terms of (a) reduced agricultural fossil fuel emissions, and (b) increased soil carbon sequestration. We estimate that 100% conversion to no-till farming would be likely to sequester about 23 Tg C y^–11 in the European Union or about 43 Tg C y^–1 in the wider Europe (excluding the former Soviet Union). In addition, up to 3.2 Tg C y^–1 could be saved in agricultural fossil fuel emissions. Compared to estimates of the potential for carbon sequestration of other carbon mitigation options, no-till agriculture shows nearly twice the potential of scenarios whereby soils are amended with organic materials. Our calculations suggest that 100% conversion to no-till agriculture in Europe could mitigate all fossil fuel-carbon emissions from agriculture in Europe. However, this is equivalent to only about 4.1% of total anthropogenic CO2-carbon produced annually in Europe (excluding the former Soviet Union) which in turn is equivalent to about 0.8% of global annual anthropogenic CO2-carbon emissions.

Water yield and hydrology

Treesearch

Pamela J. Edwards; Charles A. Troendle

2012-01-01

Investigations of hydrologic responses resulting from reducing vegetation density are fairly common throughout the Eastern United States. Although most studies have focused on the potential for increasing water yields or documenting effects from intensive practices that far exceed what would be done for fuel-reduction objectives, data from some less-intensive...

Climate impacts of air quality policy: switching to a natural gas-fueled public transportation system in New Delhi.

PubMed

Reynolds, Conor C O; Kandlikar, Milind

2008-08-15

Between 2001 and 2003, public transport vehicles in New Delhi were required to switch their fuel to natural gas in an attemptto reduce their air pollution impacts. This study examines the climatic impacts of New Delhi's fuel switching policy, and outlines implications for such efforts in rapidly industrializing countries. Natural gas is mostly composed of methane, an important greenhouse gas. Emitted aerosols (black carbon, particulate organic carbon, and sulfate) also cause radiative forcing. We find that methane and black carbon emissions are critical contributors to the change in carbon dioxide equivalent [CO2(e)] emissions. In New Delhi, the switch to natural gas results in a 30% increase in CO2(e) when the impact of aerosols is not considered. However, when aerosol emissions are taken into account in our model, the net effect of the switch is estimated to be a 10% reduction in CO2(e), and there may be as much as a 30% reduction in CO2(e). There is significant potential for emissions reductions through the United Nations Framework Convention on Climate Change (UNFCCC) Clean Development Mechanism for such fuel switching projects.

Local and systemic toxicity of JP-8 from cutaneous exposures.

PubMed

McDougal, James N; Rogers, James V

2004-04-01

Jet propellant-8 (JP-8) jet fuel is a version of commercial jet fuel, Jet A, and is a complex mixture of primarily aliphatic (but also aromatic) hydrocarbons that varies in composition from batch to batch. There is potential for dermal exposure to jet fuels with personnel involved in aircraft refueling and maintenance operations as well as ground personnel. Cutaneous exposures have the potential to cause skin irritation, sensitization or skin cancer. JP-8 has been shown to be irritating and causes molecular changes in the skin of laboratory animals. The mechanisms of some of these effects have been investigated in intact skin and cultured skin cells. Hydrocarbons have also been shown to cause skin cancer with repeated application to the skin. Additionally, there is concern about systemic toxicity from dermal exposures to jet fuels, such as JP-8. Assessing risks from systemic absorption of hydrocarbon components is complex because most of the components are present in the mixture in small quantities (less than 1%). The effect of the fuel as a vehicle, different rates of penetration through the skin and different target organ toxicities all complicate the assessment of the hazards of cutaneous exposures. The purpose of this manuscript is to review studies of local and systemic toxicity of JP-8.

Fuel level sensor based on polymer optical fiber Bragg gratings for aircraft applications

NASA Astrophysics Data System (ADS)

Marques, C. A. F.; Pospori, A.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

2016-04-01

Safety in civil aviation is increasingly important due to the increase in flight routes and their more challenging nature. Like other important systems in aircraft, fuel level monitoring is always a technical challenge. The most frequently used level sensors in aircraft fuel systems are based on capacitive, ultrasonic and electric techniques, however they suffer from intrinsic safety concerns in explosive environments combined with issues relating to reliability and maintainability. In the last few years, optical fiber liquid level sensors (OFLLSs) have been reported to be safe and reliable and present many advantages for aircraft fuel measurement. Different OFLLSs have been developed, such as the pressure type, float type, optical radar type, TIR type and side-leaking type. Amongst these, many types of OFLLSs based on fiber gratings have been demonstrated. However, these sensors have not been commercialized because they exhibit some drawbacks: low sensitivity, limited range, long-term instability, or limited resolution. In addition, any sensors that involve direct interaction of the optical field with the fuel (either by launching light into the fuel tank or via the evanescent field of a fiber-guided mode) must be able to cope with the potential build up of contamination - often bacterial - on the optical surface. In this paper, a fuel level sensor based on microstructured polymer optical fiber Bragg gratings (mPOFBGs), including poly (methyl methacrylate) (PMMA) and TOPAS fibers, embedded in diaphragms is investigated in detail. The mPOFBGs are embedded in two different types of diaphragms and their performance is investigated with aviation fuel for the first time, in contrast to our previous works, where water was used. Our new system exhibits a high performance when compared with other previously published in the literature, making it a potentially useful tool for aircraft fuel monitoring.

Diesel engine performance and emissions with fuels derived from waste tyres.

PubMed

Verma, Puneet; Zare, Ali; Jafari, Mohammad; Bodisco, Timothy A; Rainey, Thomas; Ristovski, Zoran D; Brown, Richard J

2018-02-06

The disposal of waste rubber and scrap tyres is a significant issue globally; disposal into stockpiles and landfill poses a serious threat to the environment, in addition to creating ecological problems. Fuel production from tyre waste could form part of the solution to this global issue. Therefore, this paper studies the potential of fuels derived from waste tyres as alternatives to diesel. Production methods and the influence of reactor operating parameters (such as reactor temperature and catalyst type) on oil yield are outlined. These have a major effect on the performance and emission characteristics of diesel engines when using tyre derived fuels. In general, tyre derived fuels increase the brake specific fuel consumption and decrease the brake thermal efficiency. The majority of studies indicate that NOx emissions increase with waste tyre derived fuels; however, a few studies have reported the opposite trend. A similar increasing trend has been observed for CO and CO 2 emissions. Although most studies reported an increase in HC emission owing to lower cetane number and higher density, some studies have reported reduced HC emissions. It has been found that the higher aromatic content in such fuels can lead to increased particulate matter emissions.

Investigation into the Implications of Fuel Cell Shipboard Integration into the T-AGOS 19 Class

DTIC Science & Technology

2012-02-01

with each defined by its fundamental electrolyte: i. Alkali Fuel Cells (AFC) ii. Polymer Exchange Membrane ( PEM ) iii. Phosphoric Acid Fuel Cells ...of the PEM family (High Temperature – HTPEM and Direct Methanol Fuel Cells – DMFC) were assessed against a range of basic ship requirements...of fuel cell stacks in 100+kW power range for realistic marine applications, two technologies can be quickly discounted, namely – AFC, DMFC. PEM

Autoxidation of jet fuels: Implications for modeling and thermal stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heneghan, S.P.; Chin, L.P.

1995-05-01

The study and modeling of jet fuel thermal deposition is dependent on an understanding of and ability to model the oxidation chemistry. Global modeling of jet fuel oxidation is complicated by several facts. First, liquid jet fuels are hard to heat rapidly and fuels may begin to oxidize during the heat-up phase. Non-isothermal conditions can be accounted for but the evaluation of temperature versus time is difficult. Second, the jet fuels are a mixture of many compounds that may oxidize at different rates. Third, jet fuel oxidation may be autoaccelerating through the decomposition of the oxidation products. Attempts to modelmore » the deposition of jet fuels in two different flowing systems showed the inadequacy of a simple two-parameter global Arrhenius oxidation rate constant. Discarding previous assumptions about the form of the global rate constants results in a four parameter model (which accounts for autoacceleration). This paper discusses the source of the rate constant form and the meaning of each parameter. One of these parameters is associated with the pre-exponential of the autoxidation chain length. This value is expected to vary inversely to thermal stability. We calculate the parameters for two different fuels and discuss the implication to thermal and oxidative stability of the fuels. Finally, we discuss the effect of non-Arrhenius behavior on current modeling of deposition efforts.« less

Biomass conservation potential of pottery/ceramic lined Mamta Stove: An improved stove promoted under National Programme on Improved Cookstoves in India

DOE Office of Scientific and Technical Information (OSTI.GOV)

George, R.; Yadla, V.L.

1995-10-01

To combat biomass scarcity and ensure a cleaner cooking environment with less drudgery, among other things, a variety of improved stoves are promoted under National Programme on Improved Cookstoves (NPIC). Mamta Stove (MS) is one among such improved stoves. An indepth study was undertaken covering a sample of twenty-five rural families with the primary objective of assessing fuel saving potential of MS under field conditions through Kitchen Performance Test (KPT). Conventional stove (CS) used in almost all the families was shielded horse-shoe shaped stove with a negligible proportion using three stone open fire. Nearly 88% depended only on zero privatemore » cost fuels. The mean number of persons for whom the stoves were used on the days of field measurements in case of CS and MS were 5.6 and 5.7 respectively with an SD of 1.16 and standard adult equivalent (SAE) was approximately 4. Cooking pots included a concave roasting pan, a deep frying pan and flat bottomed pots. The mean daily fuel consumption on CS and MS were estimated to be 4.88 kg and 3.75 kg respective, thereby, resulting in fuel saving to the tune of 24% on MS. The paper discusses at length the design features of CS and MS, meal pattern, cooking habits, need for user training, consumerism in the area of cooking and stove technology, economics of switching over to MS and policy implications of commercialization of hitherto subsidized stove program. Further, salient characteristics of high and low cooking fuel consumers on MS are presented to bring to limelight their profile.« less

Near-Infrared Imaging for Spatial Mapping of Organic Content in Petroleum Source Rocks

NASA Astrophysics Data System (ADS)

Mehmani, Y.; Burnham, A. K.; Vanden Berg, M. D.; Tchelepi, H.

2017-12-01

Natural gas from unconventional petroleum source rocks (shales) plays a key role in our transition towards sustainable low-carbon energy production. The potential for carbon storage (in adsorbed state) in these formations further aligns with efforts to mitigate climate change. Optimizing production and development from these resources requires knowledge of the hydro-thermo-mechanical properties of the rock, which are often strong functions of organic content. This work demonstrates the potential of near-infrared (NIR) spectral imaging in mapping the spatial distribution of organic content with O(100µm) resolution on cores that can span several hundred feet in depth (Mehmani et al., 2017). We validate our approach for the immature oil shale of the Green River Formation (GRF), USA, and show its applicability potential in other formations. The method is a generalization of a previously developed optical approach specialized to the GRF (Mehmani et al., 2016a). The implications of this work for spatial mapping of hydro-thermo-mechanical properties of excavated cores, in particular thermal conductivity, are discussed (Mehmani et al., 2016b). References:Mehmani, Y., A.K. Burnham, M.D. Vanden Berg, H. Tchelepi, "Quantification of organic content in shales via near-infrared imaging: Green River Formation." Fuel, (2017). Mehmani, Y., A.K. Burnham, M.D. Vanden Berg, F. Gelin, and H. Tchelepi. "Quantification of kerogen content in organic-rich shales from optical photographs." Fuel, (2016a). Mehmani, Y., A.K. Burnham, H. Tchelepi, "From optics to upscaled thermal conductivity: Green River oil shale." Fuel, (2016b).

Combined Heat and Power Market Potential for Opportunity Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, David; Lemar, Paul

This report estimates the potential for opportunity fuel combined heat and power (CHP) applications in the United States, and provides estimates for the technical and economic market potential compared to those included in an earlier report. An opportunity fuel is any type of fuel that is not widely used when compared to traditional fossil fuels. Opportunity fuels primarily consist of biomass fuels, industrial waste products and fossil fuel derivatives. These fuels have the potential to be an economically viable source of power generation in various CHP applications.

The thermolysin family (M4) of enzymes: therapeutic and biotechnological potential.

PubMed

Adekoya, Olayiwola A; Sylte, Ingebrigt

2009-01-01

Zinc containing peptidases are widely distributed in nature and have important roles in many physiological processes. M4 family comprises numerous zinc-dependent metallopeptidases that hydrolyze peptide bonds. A large number of these enzymes are implicated as virulence factors of the microorganisms that produce them and are therefore potential drug targets. Some enzymes of the family are able to function at the extremes of temperatures, and some function in organic solvents. Thereby enzymes of the thermolysin family have an innovative potential for biotechnological applications.

The virtual revolution: implications for academe.

PubMed

Pardue, S L

2001-05-01

The global expansion and acceptance of the Internet as been unprecedented. The emergence of the potential for distance learning (DL) has altered the way in which faculty, university administrators, and for-profit corporations view the educational process. In 1998, nearly 80% of public 4-yr institutions offered some DL courses. However, DL courses in agriculture and natural resources represented less than 1% of the total enrollment. Like any technology that ushers in a new era of change, DL has attracted enthusiastic supporters and detractors. Few view DL with neutrality. It is this divergence of opinion that has fueled the debate over the academic value of DL. A valid evaluation of the educational benefits or deficiencies of DL may require additional long-term studies. For some academic traditionalists, DL is viewed as the fusion of education and commerce and borders on the repugnant. Others embrace DL not only because it may provide a source of much needed revenue, but also because it allows for the low-cost delivery of information to a nontraditional pool of students. Well-funded, private, for-profit organizations and universities have developed a number of DL models. Some hybrid DL models exist in which public institutions have created independent for-profit corporations to develop and distribute their web-based courses. The question is not if DL will be a part of the educational landscape; it surely will. The challenge is to define the role DL can most effectively fulfill.

Bio-analytical applications of microbial fuel cell-based biosensors for onsite water quality monitoring.

PubMed

ElMekawy, A; Hegab, H M; Pant, D; Saint, C P

2018-01-01

Globally, sustainable provision of high-quality safe water is a major challenge of the 21st century. Various chemical and biological monitoring analytics are presently utilized to guarantee the availability of high-quality water. However, these techniques still face some challenges including high costs, complex design and onsite and online limitations. The recent technology of using microbial fuel cell (MFC)-based biosensors holds outstanding potential for the rapid and real-time monitoring of water source quality. MFCs have the advantages of simplicity in design and efficiency for onsite sensing. Even though some sensing applications of MFCs were previously studied, e.g. biochemical oxygen demand sensor, recently numerous research groups around the world have presented new practical applications of this technique, which combine multidisciplinary scientific knowledge in materials science, microbiology and electrochemistry fields. This review presents the most updated research on the utilization of MFCs as potential biosensors for monitoring water quality and considers the range of potentially toxic analytes that have so far been detected using this methodology. The advantages of MFCs over established technology are also considered as well as future work required to establish their routine use. © 2017 The Society for Applied Microbiology.

75 FR 45167 - Notice of Public Workshop on a Potential Rulemaking for Spent Nuclear Fuel Reprocessing Facilities

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-02

... more sophisticated reprocessing technology. During the Bush Administration, the Global Nuclear Energy... Associated with the Global Nuclear Energy Partnership,'' dated June 27, 2007 (ADAMS ML071800084), directed... on some Global Nuclear Energy Partnership (GNEP) initiatives had waned and it appeared appropriate to...

Microbiological and engineering aspects of biohydrogen production.

PubMed

Hallenbeck, Patrick C; Ghosh, Dipankar; Skonieczny, Monika T; Yargeau, Viviane

2009-03-01

Dramatically rising oil prices and increasing awareness of the dire environmental consequences of fossil fuel use, including startling effects of climate change, are refocusing attention worldwide on the search for alternative fuels. Hydrogen is poised to become an important future energy carrier. Renewable hydrogen production is pivotal in making it a truly sustainable replacement for fossil fuels, and for realizing its full potential in reducing greenhouse gas emissions. One attractive option is to produce hydrogen through microbial fermentation. This process would use readily available wastes as well as presently unutilized bioresources, including enormous supplies of agricultural and forestry wastes. These potential energy sources are currently not well exploited, and in addition, pose environmental problems. However, fuels are relatively low value products, placing severe constraints on any production process. Therefore, means must be sought to maximize yields and rates of hydrogen production while at the same time minimizing energy and capital inputs to the bioprocess. Here we review the various attributes of the characterized hydrogen producing bacteria as well as the preparation and properties of mixed microflora that have been shown to convert various substrates to hydrogen. Factors affecting yields and rates are highlighted and some avenues for increasing these parameters are explored. On the engineering side, we review the potential waste pre-treatment technologies and discuss the relevant bioprocess parameters, possible reactor configurations, including emerging technologies, and how engineering design-directed research might provide insight into the exploitation of the significant energy potential of biomass resources.

Evaluation Tests of Select Fuel Additives for Potential Use in U.S. Army Corps of Engineers Diesel Engines

DTIC Science & Technology

2016-07-01

DOER) program, diesel fuel additives were tested to evaluate their potential for reducing diesel fuel consumption and cost. Four fuel additives were...tested to evaluate their potential for reducing diesel fuel consumption and cost: • An ethanol injection system • Envirofuels Diesel Fuel Catalyst...reduction in select operation conditions, only the ethanol injection system consistently showed potential to reduce diesel fuel consumption , which may be

Study of active cooling for supersonic transports

NASA Technical Reports Server (NTRS)

Brewer, G. D.; Morris, R. E.

1975-01-01

The potential benefits of using the fuel heat sink of hydrogen fueled supersonic transports for cooling large portions of the aircraft wing and fuselage are examined. The heat transfer would be accomplished by using an intermediate fluid such as an ethylene glycol-water solution. Some of the advantages of the system are: (1) reduced costs by using aluminum in place of titanium, (2) reduced cabin heat loads, and (3) more favorable environmental conditions for the aircraft systems. A liquid hydrogen fueled, Mach 2.7 supersonic transport aircraft design was used for the reference uncooled vehicle. The cooled aircraft designs were analyzed to determine their heat sink capability, the extent and location of feasible cooled surfaces, and the coolant passage size and spacing.

New Temperature Monitoring Devices for High-Temperature Irradiation Experiments in the High Flux Reactor Petten

NASA Astrophysics Data System (ADS)

Laurie, M.; Futterer, M. A.; Lapetite, J. M.; Fourrez, S.; Morice, R.

2011-10-01

Within the European High Temperature Reactor Technology Network (HTR-TN) and related projects a number of HTR fuel irradiations are planned in the High Flux Reactor Petten (HFR), The Netherlands, with the objective to explore the potential of recently produced fuel for even higher temperature and burn-up. Irradiating fuel under defined conditions to extremely high burn-ups will provide a better understanding of fission product release and failure mechanisms if particle failure occurs. After an overview of the irradiation rigs used in the HFR, this paper sums up data collected from previous irradiation tests in terms of thermocouple data. Some R&D for further improvement of thermocouples and other on-line instrumentation will be outlined.

Assessing Household Solid Fuel Use: Multiple Implications for the Millennium Development Goals

PubMed Central

Rehfuess, Eva; Mehta, Sumi; Prüss-Üstün, Annette

2006-01-01

Objective The World Health Organization is the agency responsible for reporting the Millennium Development Goal (MDG) indicator “percentage of population using solid fuels.” In this article, we present the results of a comprehensive assessment of solid fuel use, conducted in 2005, and discuss the implications of our findings in the context of achieving the MDGs. Methods For 93 countries, solid fuel use data were compiled from recent national censuses or household surveys. For the 36 countries where no data were available, the indicator was modeled. For 52 upper-middle or high-income countries, the indicator was assumed to be < 5%. Results According to our assessment, 52% of the world’s population uses solid fuels. This percentage varies widely between countries and regions, ranging from 77%, 74%, and 74% in Sub-Saharan Africa, Southeast Asia, and the Western Pacific Region, respectively, to 36% in the Eastern Mediterranean Region, 16% in Latin America and the Caribbean and in Central and Eastern Europe. In most industrialized countries, solid fuel use falls to the < 5% mark. Discussion Although the “percentage of population using solid fuels” is classified as an indicator to measure progress towards MDG 7, reliance on traditional household energy practices has distinct implications for most of the MDGs, notably MDGs 4 and 5. There is an urgent need for development agendas to recognize the fundamental role that household energy plays in improving child and maternal health and fostering economic and social development. PMID:16507460

Immunotoxicity evaluation of jet a jet fuel in female rats after 28-day dermal exposure.

PubMed

Mann, Cynthia M; Peachee, Vanessa L; Trimmer, Gary W; Lee, Ji-Eun; Twerdok, Lorraine E; White, Kimber L

2008-01-01

The potential for jet fuel to modulate immune functions has been reported in mice following dermal, inhalation, and oral routes of exposure; however, a functional evaluation of the immune system in rats following jet fuel exposure has not been conducted. In this study potential effects of commercial jet fuel (Jet A) on the rat immune system were assessed using a battery of functional assays developed to screen potential immunotoxic compounds. Jet A was applied to the unoccluded skin of 6- to 7-wk-old female Crl:CD (SD)IGS BR rats at doses of 165, 330, or 495 mg/kg/d for 28 d. Mineral oil was used as a vehicle to mitigate irritation resulting from repeated exposure to jet fuel. Cyclophosphamide and anti-asialo GM1 were used as positive controls for immunotoxic effects. In contrast to reported immunotoxic effects of jet fuel in mice, dermal exposure of rats to Jet A did not result in alterations in spleen or thymus weights, splenic lymphocyte subpopulations, immunoglobulin (Ig) M antibody-forming cell response to the T-dependent antigen, sheep red blood cells (sRBC), spleen cell proliferative response to anti-CD3 antibody, or natural killer (NK) cell activity. In each of the immunotoxicological assays conducted, the positive control produced the expected results, demonstrating the assay was capable of detecting an effect if one had occurred. Based on the immunological parameters evaluated under the experimental conditions of the study, Jet A did not adversely affect immune responses of female rats. It remains to be determined whether the observed difference between this study and some other studies reflects a difference in the immunological response of rats and mice or is the result of other factors.

Compressed Natural Gas Vehicle Maintenance Facility Modification Handbook

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Kay L.; Ramsden, Margo M.; Gonzales, John E.

To ensure the safety of personnel and facilities, vehicle maintenance facilities are required by law and by guidelines of the National Fire Protection Association (NFPA) and the International Fire Code (IFC) to exhibit certain design features. They are also required to be fitted with certain fire protection equipment and devices because of the potential for fire or explosion in the event of fuel leakage or spills. All fuels have an explosion or fire potential if specific conditions are present. The hazard presented by liquid fuels, such as gasoline and diesel, results from the spillage of these liquids and subsequent ignitionmore » of vapors, causing a fire or explosion. Facilities that maintain liquid-fueled vehicles and implement appropriate safety measures are protected with ventilation systems designed to capture liquid fuel vapors at or near floor level. To minimize the potential for ignition in the event of a spill, receptacles, electrical fixtures, and hot-work operations, such as welding, are located outside of these areas. Compressed natural gas (CNG) is composed of methane with slight amounts of heavier simple hydrocarbons. Maintenance facilities that maintain CNG vehicles indoors must be protected against fire and explosion. However, the means of ensuring safety are different from those employed for liquid fuels because of the gaseous nature of methane and the fact that it is lighter than air. Because CNG is lighter than air, a release will rise to the ceiling of the maintenance facility and quickly dissipate rather than remaining at or near floor level like liquid fuel vapors. Although some of the means of protection for CNG vehicle maintenance facilities are similar to those used for liquid-fueled vehicles (ventilation and elimination of ignition sources), the types and placement of the protection equipment are different because of the behavior of the different fuels. The nature of gaseous methane may also require additional safeguards, such as combustible gas detectors and control systems, or specialized space heating, which are not needed in facilities servicing liquid-fuel vehicles. This handbook covers maintenance facilities that service CNG-fueled vehicles. Although similar requirements are mandated for liquefied natural gas (LNG) or liquefied petroleum gas (LPG) fueled vehicles, LNG and LPG are not covered in this handbook.« less

Solar energy to biofuels.

PubMed

Agrawal, Rakesh; Singh, Navneet R

2010-01-01

In a solar economy, sustainably available biomass holds the potential to be an excellent nonfossil source of high energy density transportation fuel. However, if sustainably available biomass cannot supply the liquid fuel need for the entire transport sector, alternatives must be sought. This article reviews biomass to liquid fuel conversion processes that treat biomass primarily as a carbon source and boost liquid fuel production substantially by using supplementary energy that is recovered from solar energy at much higher efficiencies than the biomass itself. The need to develop technologies for an energy-efficient future sustainable transport sector infrastructure that will use different forms of energy, such as electricity, H(2), and heat, in a synergistic interaction with each other is emphasized. An enabling template for such a future transport infrastructure is presented. An advantage of the use of such a template is that it reduces the land area needed to propel an entire transport sector. Also, some solutions for the transition period that synergistically combine biomass with fossil fuels are briefly discussed.

The Carbon Cycle: Implications for Climate Change and Congress

DTIC Science & Technology

2008-03-13

burning of fossil fuels, deforestation , and other land use activities, have significantly altered the carbon cycle. As a result, atmospheric...80% of human-related CO2 emissions results from fossil fuel combustion, and 20% from land use change (primarily deforestation ). Fossil fuel burning...warming the planet. At present, the oceans and land surface are acting as sinks for CO2 emitted from fossil fuel combustion and deforestation , but

Nitrous oxide emissions control by reburning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rutar, T.; Kramlich, J.C.; Malte, P.C.

1996-12-01

Fluidized bed coal combustors emit much higher concentrations of nitrous oxide (N{sub 2}O) than do most other combustion systems. This is of concern because N{sub 2}O is highly stable in the atmosphere, and may contribute to both the greenhouse effect and to stratospheric ozone depletion. In this article laboratory results are presented on N{sub 2}O removal by the reburning (i.e., afterburning) method. The destruction of N{sub 2}O is observed during contact between hot flue gases containing N{sub 2}O and various reburning fuels. A laboratory combustion reactor is used to sequentially generate the hot combustion gas, and to put this gasmore » in contact with N{sub 2}O and reburning fuel under well-characterized conditions. The initial N{sub 2}O in the primary combustion products is between 200 and 350 ppmv (dry). The temperature of the primary combustion products is varied between 1,080 and 1,370 K, and the oxygen level of these gases is varied between 3.3 and 4.8% (dry). Five reburning fuels are tested. The rank order of reburning effectiveness (based on equal heat input by the reburning fuels) is H{sub 2} > CH{sub 4} > C{sub 2}H{sub 4} and C{sub 2}H{sub 6} > CO. Experiments are also performed with the primary combustor operated fuel rich. Without any reburning fuel added, removal of large amounts of N{sub 2}O are obtained when the fuel-air equivalence ratio of the primary combustion is about 1.1. The experimental results are presented, discussed, and compared to chemical kinetic modeling. Also, some discussions of the practical implications is presented.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, A.; Repac, B.; Gonder, J.

This poster presents initial estimates of the net energy impacts of automated vehicles (AVs). Automated vehicle technologies are increasingly recognized as having potential to decrease carbon dioxide emissions and petroleum consumption through mechanisms such as improved efficiency, better routing, lower traffic congestion, and by enabling advanced technologies. However, some effects of AVs could conceivably increase fuel consumption through possible effects such as longer distances traveled, increased use of transportation by underserved groups, and increased travel speeds. The net effect on petroleum use and climate change is still uncertain. To make an aggregate system estimate, we first collect best estimates formore » the energy impacts of approximately ten effects of AVs. We then use a modified Kaya Identity approach to estimate the range of aggregate effects and avoid double counting. We find that depending on numerous factors, there is a wide range of potential energy impacts. Adoption of automated personal or shared vehicles can lead to significant fuel savings but has potential for backfire.« less

Multiple Irradiation Capsule Experiment (MICE)-3B Irradiation Test of Space Fuel Specimens in the Advanced Test Reactor (ATR) - Close Out Documentation for Naval Reactors (NR) Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Chen; CM Regan; D. Noe

2006-01-09

Few data exist for UO{sub 2} or UN within the notional design space for the Prometheus-1 reactor (low fission rate, high temperature, long duration). As such, basic testing is required to validate predictions (and in some cases determine) performance aspects of these fuels. Therefore, the MICE-3B test of UO{sub 2} pellets was designed to provide data on gas release, unrestrained swelling, and restrained swelling at the upper range of fission rates expected for a space reactor. These data would be compared with model predictions and used to determine adequacy of a space reactor design basis relative to fission gas releasemore » and swelling of UO{sub 2} fuel and to assess potential pellet-clad interactions. A primary goal of an irradiation test for UN fuel was to assess performance issues currently associated with this fuel type such as gas release, swelling and transient performance. Information learned from this effort may have enabled use of UN fuel for future applications.« less

Overpressure resulting from combustion of explosive gas in an unconfined geometry

NASA Astrophysics Data System (ADS)

Urtiew, P. A.

1982-02-01

In preparation for a series of large scale spill tests of liquefied gaseous fuels, the problem of designing safe storage facilities for the fuels as part of a proposed spill test facility arose. The design had to take into account the potential hazards associated with large quantities of fuel, including the hazard of overpressures which develop during various modes of combustion or explosion. The overpressure question, the results of which are presented, was studied. All the pertinent information on overpressure that is available in the open literature is summarized and is presented in a form that can be readily converted into design criteria for the fuel storage facility. Various modes of combustion are reviewed and categorized according to their capability of producing sizable overpressures, and some comments are made on how deviations from the ideal situations considered in analytical studies will affect the results.

Quantifying the air quality-CO2 tradeoff potential for airports

NASA Astrophysics Data System (ADS)

Ashok, Akshay; Dedoussi, Irene C.; Yim, Steve H. L.; Balakrishnan, Hamsa; Barrett, Steven R. H.

2014-12-01

Aircraft movements on the airport surface are responsible for CO2 emissions that contribute to climate change and other emissions that affect air quality and human health. While the potential for optimizing aircraft surface movements to minimize CO2 emissions has been assessed, the implications of CO2 emissions minimization for air quality have not been quantified. In this paper, we identify conditions in which there is a tradeoff between CO2 emissions and population exposure to O3 and secondary PM2.5 - i.e. where decreasing fuel burn (which is directly proportional to CO2 emissions) results in increased exposure. Fuel burn and emissions are estimated as a function of thrust setting for five common gas turbine engines at 34 US airports. Regional air quality impacts, which are dominated by ozone and secondary PM2.5, are computed as a function of airport location and time using the adjoint of the GEOS-Chem chemistry-transport model. Tradeoffs between CO2 emissions and population exposure to PM2.5 and O3 occur between 2-18% and 5-60% of the year, respectively, depending on airport location, engine type, and thrust setting. The total duration of tradeoff conditions is 5-12 times longer at maximum thrust operations (typical for takeoff) relative to 4% thrust operations (typical for taxiing). Per kilogram of additional fuel burn at constant thrust setting during tradeoff conditions, reductions in population exposure to PM2.5 and O3 are 6-13% and 32-1060% of the annual average (positive) population exposure per kilogram fuel burn, where the ranges encompass the medians over the 34 airports. For fuel burn increases due to thrust increases (i.e. for constant operating time), reductions in both PM2.5 and O3 exposure are 1.5-6.4 times larger in magnitude than those due to increasing fuel burn at constant thrust (i.e. increasing operating time). Airports with relatively high population exposure reduction potentials - which occur due to a combination of high duration and magnitude of tradeoff conditions - are identified. Our results are the first to quantify the extent of the tradeoff between CO2 emissions and air quality impacts at airports. This raises the possibility of reducing the air quality impacts of airports beyond minimizing fuel burn and/or optimizing for minimum net environmental impact.

Impact of thermal spectrum small modular reactors on performance of once-through nuclear fuel cycles with low-enriched uranium

DOE PAGES

Brown, Nicholas R.; Worrall, Andrew; Todosow, Michael

2016-11-18

Small modular reactors (SMRs) offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of SMRs on nuclear fuel cycle performance. The focus of this paper is the fuel cycle impacts of light water SMRs in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary example reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Options Campaign. The hypothetical light water SMR example case considered in these preliminary scoping studies ismore » a cartridge type one-batch core with slightly less than 5.0% enrichment. Challenges associated with SMRs include increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burnup in the reactor and the fuel cycle performance. This paper summarizes a list of the factors relevant to SMR fuel, core, and operation that will impact fuel cycle performance. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burnup of the reactor. Fuel cycle performance metrics for a hypothetical example SMR are compared with those for a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. The metrics performance for such an SMR is degraded for the mass of spent nuclear fuel and high-level waste disposed of, mass of depleted uranium disposed of, land use per energy generated, and carbon emissions per energy generated. Finally, it is noted that the features of some SMR designs impact three main aspects of fuel cycle performance: (1) small cores which means high leakage (there is a radial and axial component), (2) no boron which means heterogeneous core and extensive use of control rods and BPs, and (3) single batch cores. But not all of the SMR designs have all of these traits. As a result, the approach used in this study is therefore a bounding case and not all SMRs may be affected to the same extent.« less

Forest structure and downed woody debris in boreal, temperate, and tropical forest fragments.

PubMed

Gould, William A; González, Grizelle; Hudak, Andrew T; Hollingsworth, Teresa Nettleton; Hollingsworth, Jamie

2008-12-01

Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically younger) vs. closed canopy (typically older) stands, and size, i.e., small (10-14 ha), medium (33 to 60 ha), and large (100-240 ha) along a climatic gradient of boreal, temperate, and tropical forests. We measured duff, litter, fine and coarse woody debris, standing dead, and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior. The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature, moisture, structure, and fragment size. We found nonlinear relationships of coarse woody debris, fine woody debris, standing dead and live tree biomass with mean annual median temperature. Biomass for these variables was greatest in temperate sites. Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites. In a five-way multivariate analysis of variance we found that temperature, moisture, and age/structure had significant effects on forest floor fuels, downed woody debris, and live tree biomass. Fragment size had an effect on forest floor fuels and live tree biomass. Distance from forest edge had significant effects for only a few subgroups sampled. With some exceptions edges were not distinguishable from interiors in terms of fuels.

Some contributions to energetics by the Lewis Research Center and a review of their potential non-aerospace applications

NASA Technical Reports Server (NTRS)

Graham, R. W.; Gutstein, M. U.

1972-01-01

The primary technology areas are aerospace propulsion, power and materials. As examples in these technologies, the programs in the fields of cryogenics and liquid metals are reviewed and potential non-aerospace applications for the results of these programs are discussed. These include such possibilities as: hydrogen as a non-polluting industrial fuel; more efficient central power stations; and powerplants for advanced ground transportation.

Managing CO{sub 2} emissions in Nigeria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obioh, I.B.; Oluwole, A.F.; Akeredolu, F.A.

The energy resources in Nigeria are nearly equally divided between fossil fuels and biofuels. The increasing pressure on them, following expected increased population growth, may lead to substantial emissions of carbon into the atmosphere. Additionally agricultural and forestry management practices in vogue are those related to savannah burning and rotational bush fallow systems, which have been clearly implicated as important sources of CO{sub 2} and trace gases. An integrated model for the prediction of future CO{sub 2} emissions based on fossil fuels and biomass fuels requirements, rates of deforestation and other land-use indices is presented. This is further based onmore » trends in population and economic growth up to the year 2025, with a base year in 1988. A coupled carbon cycle-climate model based on the contribution of CO{sub 2} and other trace gases is established from the proportions of integrated global warming effects for a 20-year averaging time using the product of global warming potential (GWP) and total emissions. An energy-technology inventory approach to optimal resources management is used as a tool for establishing the future scope of reducing the CO{sub 2} emissions through improved fossil fuel energy efficiencies. Scenarios for reduction based on gradual to swift shifts from biomass to fossil and renewable fuels are presented together with expected policy options required to effect them.« less

KEY RESULTS FROM IRRADIATION AND POST-IRRADIATION EXAMINATION OF AGR-1 UCO TRISO FUEL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demkowicz, Paul A.; Hunn, John D.; Petti, David A.

The AGR-1 irradiation experiment was performed as the first test of tristructural isotropic (TRISO) fuel in the US Advanced Gas Reactor Fuel Development and Qualification Program. The experiment consisted of 72 right cylinder fuel compacts containing approximately 3×105 coated fuel particles with uranium oxide/uranium carbide (UCO) fuel kernels. The fuel was irradiated in the Advanced Test Reactor for a total of 620 effective full power days. Fuel burnup ranged from 11.3 to 19.6% fissions per initial metal atom and time average, volume average irradiation temperatures of the individual compacts ranged from 955 to 1136°C. This paper focuses on key resultsmore » from the irradiation and post-irradiation examination, which revealed a robust fuel with excellent performance characteristics under the conditions tested and have significantly improved the understanding of UCO coated particle fuel irradiation behavior within the US program. The fuel exhibited a very low incidence of TRISO coating failure during irradiation and post-irradiation safety testing at temperatures up to 1800°C. Advanced PIE methods have allowed particles with SiC coating failure to be isolated and meticulously examined, which has elucidated the specific causes of SiC failure in these specimens. The level of fission product release from the fuel during irradiation and post-irradiation safety testing has been studied in detail. Results indicated very low release of krypton and cesium through intact SiC and modest release of europium and strontium, while also confirming the potential for significant silver release through the coatings depending on irradiation conditions. Focused study of fission products within the coating layers of irradiated particles down to nanometer length scales has provided new insights into fission product transport through the coating layers and the role various fission products may have on coating integrity. The broader implications of these results and the application of lessons learned from AGR-1 to fuel fabrication and post-irradiation examination for subsequent fuel irradiation experiments as part of the US fuel program is also discussed.« less

Key results from irradiation and post-irradiation examination of AGR-1 UCO TRISO fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Demkowicz, Paul A.; Hunn, John D.; Petti, David A.

The AGR-1 irradiation experiment was performed as the first test of tristructural isotropic (TRISO) fuel in the US Advanced Gas Reactor Fuel Development and Qualification Program. The experiment consisted of 72 right cylinder fuel compacts containing approximately 3 × 105 coated fuel particles with uranium oxide/uranium carbide (UCO) fuel kernels. The fuel was irradiated in the Advanced Test Reactor for a total of 620 effective full power days. Fuel burnup ranged from 11.3 to 19.6% fissions per initial metal atom and time-average, volume-average irradiation temperatures of the individual compacts ranged from 955 to 1136 °C. This paper focuses on keymore » results from the irradiation and post-irradiation examination, which revealed a robust fuel with excellent performance characteristics under the conditions tested and have significantly improved the understanding of UCO coated particle fuel irradiation behavior. The fuel exhibited zero TRISO coating failures (failure of all three dense coating layers) during irradiation and post-irradiation safety testing at temperatures up to 1700 °C. Advanced PIE methods have allowed particles with SiC coating failure that were discovered to be present in a very-low population to be isolated and meticulously examined, which has elucidated the specific causes of SiC failure in these specimens. The level of fission product release from the fuel during irradiation and post-irradiation safety testing has been studied in detail. Results indicated very low release of krypton and cesium through intact SiC and modest release of europium and strontium, while also confirming the potential for significant silver release through the coatings depending on irradiation conditions. Focused study of fission products within the coating layers of irradiated particles down to nanometer length scales has provided new insights into fission product transport through the coating layers and the role various fission products may have on coating integrity. The broader implications of these results and the application of lessons learned from AGR-1 to fuel fabrication and post-irradiation examination for subsequent fuel irradiation experiments as part of the US fuel program are also discussed.« less

Key results from irradiation and post-irradiation examination of AGR-1 UCO TRISO fuel

DOE PAGES

Demkowicz, Paul A.; Hunn, John D.; Petti, David A.; ...

2017-09-10

The AGR-1 irradiation experiment was performed as the first test of tristructural isotropic (TRISO) fuel in the US Advanced Gas Reactor Fuel Development and Qualification Program. The experiment consisted of 72 right cylinder fuel compacts containing approximately 3 × 105 coated fuel particles with uranium oxide/uranium carbide (UCO) fuel kernels. The fuel was irradiated in the Advanced Test Reactor for a total of 620 effective full power days. Fuel burnup ranged from 11.3 to 19.6% fissions per initial metal atom and time-average, volume-average irradiation temperatures of the individual compacts ranged from 955 to 1136 °C. This paper focuses on keymore » results from the irradiation and post-irradiation examination, which revealed a robust fuel with excellent performance characteristics under the conditions tested and have significantly improved the understanding of UCO coated particle fuel irradiation behavior. The fuel exhibited zero TRISO coating failures (failure of all three dense coating layers) during irradiation and post-irradiation safety testing at temperatures up to 1700 °C. Advanced PIE methods have allowed particles with SiC coating failure that were discovered to be present in a very-low population to be isolated and meticulously examined, which has elucidated the specific causes of SiC failure in these specimens. The level of fission product release from the fuel during irradiation and post-irradiation safety testing has been studied in detail. Results indicated very low release of krypton and cesium through intact SiC and modest release of europium and strontium, while also confirming the potential for significant silver release through the coatings depending on irradiation conditions. Focused study of fission products within the coating layers of irradiated particles down to nanometer length scales has provided new insights into fission product transport through the coating layers and the role various fission products may have on coating integrity. The broader implications of these results and the application of lessons learned from AGR-1 to fuel fabrication and post-irradiation examination for subsequent fuel irradiation experiments as part of the US fuel program are also discussed.« less

A Comparison of the Performance Capabilities of Radioisotope Energy Conversion Systems, Betavoltaic Cells, and other Nuclear Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Steinfelds, Eric V; Prelas, Mark A.; Sudarshan, Loyalka K.

2006-07-01

In this paper we compare the potential performance capabilities of several types of nuclear batteries to the Radioisotope Thermocouple Generators (RTG's) currently in use. There have been theoretical evaluations of, and some experimental testing of, several types of nuclear batteries including Radioisotope Energy Conversion Systems (RECS), Direct Energy Conversion (DEC) systems, and Betavoltaic Power Cells (BPC's). It has been theoretically shown, and to some extent experimentally demonstrated, that RECS, capacitive DEC systems, and possibly BPC's are all potentially capable of efficiencies well above the 9% maximum efficiency demonstrated to date in RTG's customized for deep space probe applications. Even thoughmore » RTG's have proven their reliability and have respectable power to mass ratios, it is desirable to attain efficiencies of at least 25% in typical applications. High fuel efficiency is needed to minimize the quantities of radioisotopic or nuclear fuels in the systems, to maximize power to mass ratios, and to minimize housing requirements. It has been shown that RECS can attain electric power generation efficiencies greater than 18% for devices which use Sr-90 fuel and where the accompanying material is less than roughly twice the mass of the Sr-90 fuel. Other radioisotopic fuels such as Pu-238 or Kr-85 can also be placed into RECS in order to attain efficiencies over 18%. With the likely exception of one fuel investigated by the authors, all of the promising candidates for RECS fuels can attain electric power to mass ratios greater than 15 W kg{sup -1}. It has been claimed recently [1] that the efficiency of tritium-fueled BPC's can be as high as 25%. While this is impressive and tritium has the benefit of being a 'soft' radioisotopic fuel, the silicon wafer that holds the tritium would have to be considerably more massive than the tritium contained within it and immediately adjacent to the wafer. Considering realistic mass requirements for the presence of silicon in the bulk of the wafer, a tritium cell would thus be limited to power to mass ratios <3 W kg{sup -1}. Even RECS designs with more energetic fuels and higher shielding burdens can attain >3 W kg{sup -1} and efficiencies exceeding 20%. Capacitive DEC systems can also offer significant benefits. With larger fuel quantities and larger dimensions, DEC systems can attain power efficiencies >50%. For small nuclear batteries of low or medium power, RECS appear highly desirable since the efficiency of a RECS does not vary with the amount of fuel present nor does it vary with temperature to any significant degree. (authors)« less

Metabolic fuel and clinical implications for female reproduction.

PubMed

Mircea, Carmen N; Lujan, Marla E; Pierson, Roger A

2007-11-01

Reproduction is a physiologically costly process that consumes significant amounts of energy. The physiological mechanisms controlling energy balance are closely linked to fertility. This close relationship ensures that pregnancy and lactation occur only in favourable conditions with respect to energy. The primary metabolic cue that modulates reproduction is the availability of oxidizable fuel. An organism's metabolic status is transmitted to the brain through metabolic fuel detectors. There are many of these detectors at both the peripheral (e.g., leptin, insulin, ghrelin) and central (e.g., neuropeptide Y, melanocortin, orexins) levels. When oxidizable fuel is scarce, the detectors function to inhibit the release of gonadotropin-releasing hormone and luteinizing hormone, thereby altering steroidogenesis, reproductive cyclicity, and sexual behaviour. Infertility can also result when resources are abundant but food intake fails to compensate for increased energy demands. Examples of these conditions in women include anorexia nervosa and exercise-induced amenorrhea. Infertility associated with obesity appears to be less related to an effect of oxidizable fuel on the hypothalamic-pituitary-ovarian axis. Impaired insulin sensitivity may play a role in the etiology of these conditions, but their specific etiology remains unresolved. Research into the metabolic regulation of reproductive function has implications for elucidating mechanisms of impaired pubertal development, nutritional amenorrhea, and obesity-related infertility. A better understanding of these etiologies has far-reaching implications for the prevention and management of reproductive dysfunction and its associated comorbidities.

Managing the Nuclear Fuel Cycle: Policy Implications of Expanding Global Access to Nuclear Power

DTIC Science & Technology

2007-11-01

critical aspect of the nuclear fuel cycle for the United States, where longstanding nonproliferation policy discouraged commercial nuclear fuel...perhaps the most critical question in this decade for strengthening the nuclear nonproliferation regime: how can access to sensitive fuel cycle...process can take advantage of the slight difference in atomic mass between 235U and 238U. The typical enrichment process requires about 10 lbs of uranium

A pilot-scale study of wet torrefaction treatment for upgrading palm oil empty fruit bunches as clean solid fuel

NASA Astrophysics Data System (ADS)

Gusman, M. H.; Sastroredjo, P. N. E.; Prawisudha, P.; Hardianto, T.; Pasek, A. D.

2017-05-01

Less utilized empty fruit bunch (EFB) is seldom used as solid biofuel due to its high alkali content that potentially cause ash deposit called slagging and fouling. This phenomenon could harm biomass-fired power plant equipment. Some pre-treatment of EFB is needed to reduce EFB ash deposit potential. The effect of wet torrefaction pre-treatment in laboratory scale was successfully proven in decreasing slagging and fouling potential while increasing EFB calorific value that could fulfill clean solid fuel criteria. This research focuses on wet torrefaction process that conducted on a pilot scale with the capacity of 250 liters. It was found that wet torrefaction process can improve the product’s calorific value up to 9.41% while reduce its ash content down to 1.01% comparing to the raw EFB. The reduction of ash content also leads to the reduction of slagging and fouling tendency that presents in terms of alkali index. Alkali index is a quantitative method that can be calculated after obtaining metal oxides fraction on solid fuel. Metal oxides could be obtained by using energy dispersive x-ray spectroscopy.

Life Cycle Water Consumption for Shale Gas and Conventional Natural Gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Corrie E.; Horner, Robert M.; Harto, Christopher B.

2013-10-15

Shale gas production represents a large potential source of natural gas for the nation. The scale and rapid growth in shale gas development underscore the need to better understand its environmental implications, including water consumption. This study estimates the water consumed over the life cycle of conventional and shale gas production, accounting for the different stages of production and for flowback water reuse (in the case of shale gas). This study finds that shale gas consumes more water over its life cycle (13–37 L/GJ) than conventional natural gas consumes (9.3–9.6 L/GJ). However, when used as a transportation fuel, shale gasmore » consumes significantly less water than other transportation fuels. When used for electricity generation, the combustion of shale gas adds incrementally to the overall water consumption compared to conventional natural gas. The impact of fuel production, however, is small relative to that of power plant operations. The type of power plant where the natural gas is utilized is far more important than the source of the natural gas.« less

Life cycle water consumption for shale gas and conventional natural gas.

PubMed

Clark, Corrie E; Horner, Robert M; Harto, Christopher B

2013-10-15

Shale gas production represents a large potential source of natural gas for the nation. The scale and rapid growth in shale gas development underscore the need to better understand its environmental implications, including water consumption. This study estimates the water consumed over the life cycle of conventional and shale gas production, accounting for the different stages of production and for flowback water reuse (in the case of shale gas). This study finds that shale gas consumes more water over its life cycle (13-37 L/GJ) than conventional natural gas consumes (9.3-9.6 L/GJ). However, when used as a transportation fuel, shale gas consumes significantly less water than other transportation fuels. When used for electricity generation, the combustion of shale gas adds incrementally to the overall water consumption compared to conventional natural gas. The impact of fuel production, however, is small relative to that of power plant operations. The type of power plant where the natural gas is utilized is far more important than the source of the natural gas.

Compliance by Design: Influence of Acceleration Trade-offs on CO2 Emissions and Costs of Fuel Economy and Greenhouse Gas Regulations.

PubMed

Whitefoot, Kate S; Fowlie, Meredith L; Skerlos, Steven J

2017-09-19

The ability of automakers to improve the fuel economy of vehicles using engineering design modifications that compromise other performance attributes, such as acceleration, is not currently considered when setting fuel economy and greenhouse-gas emission standards for passenger cars and light trucks. We examine the role of these design trade-offs by simulating automaker responses to recently reformed vehicle standards with and without the ability to adjust acceleration performance. Results indicate that acceleration trade-offs can be important in two respects: (1) they can reduce the compliance costs of the standards, and (2) they can significantly reduce emissions associated with a particular level of the standards by mitigating incentives to shift sales toward larger vehicles and light trucks relative to passenger cars. We contrast simulation-based results with observed changes in vehicle attributes under the reformed standards. We find evidence that is consistent with firms using acceleration trade-offs to achieve compliance. Taken together, our analysis suggests that acceleration trade-offs play a role in automaker compliance strategies with potentially large implications for both compliance costs and emissions.

Caution Regarding Exergames: A Skill Acquisition Perspective

ERIC Educational Resources Information Center

Pedersen, Scott J.; Cooley, Paul D.; Cruickshank, Vaughan J.

2017-01-01

Background: The advent of technology use in physical education is upon us. But the implications of using exergames as a substitute for traditional physical education instruction for some students raise questions. Although exergames have the potential to increase energy expenditure and motivation in some children, it is less clear whether they can…

Some peat deposits in Penobscot County, Maine

USGS Publications Warehouse

Cameron, Cornelia Clermont; Anderson, Walter A.

1979-01-01

Twenty of the peat deposits in Penobscot County, Maine contain an estimated 29,282,000 short tons air-dried peat. The peat is chiefly sphagnum moss and reed-sedge of high quality according to ASTM standards for agricultural and horticultural use. Analyses show that this same volume has high fuel value, low sulfur and high hydrogen contents compared with lignite and sub-bituminous coal, which may indicate that it also has potential for fuel use. On the basis of the metallic trace element content, one area within the region containing the 20 deposits has been delineated for further bedrock studies.

Systems for the Intermodal Routing of Spent Nuclear Fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Steven K; Liu, Cheng

The safe and secure movement of spent nuclear fuel from shutdown and active reactor facilities to intermediate or long term storage sites may, in some instances, require the use of several modes of transportation to accomplish the move. To that end, a fully operable multi-modal routing system is being developed within Oak Ridge National Laboratory s (ORNL) WebTRAGIS (Transportation Routing Analysis Geographic Information System). This study aims to provide an overview of multi-modal routing, the existing state of the TRAGIS networks, the source data needs, and the requirements for developing structural relationships between various modes to create a suitable systemmore » for modeling the transport of spent nuclear fuel via a multimodal network. Modern transportation systems are comprised of interconnected, yet separate, modal networks. Efficient transportation networks rely upon the smooth transfer of cargoes at junction points that serve as connectors between modes. A key logistical impediment to the shipment of spent nuclear fuel is the absence of identified or designated transfer locations between transport modes. Understanding the potential network impacts on intermodal transportation of spent nuclear fuel is vital for planning transportation routes from origin to destination. By identifying key locations where modes intersect, routing decisions can be made to prioritize cost savings, optimize transport times and minimize potential risks to the population and environment. In order to facilitate such a process, ORNL began the development of a base intermodal network and associated routing code. The network was developed using previous intermodal networks and information from publicly available data sources to construct a database of potential intermodal transfer locations with likely capability to handle spent nuclear fuel casks. The coding development focused on modifying the existing WebTRAGIS routing code to accommodate intermodal transfers and the selection of prioritization constraints and modifiers to determine route selection. The limitations of the current model and future directions for development are discussed, including the current state of information on possible intermodal transfer locations for spent fuel.« less

Externalities of energy use, analyzed for shipping and electricity generation

NASA Astrophysics Data System (ADS)

Thomson, Heather

Energy use is central to the modern lifestyle, but producing this energy often comes at an environmental cost. The three studies in this paper look at the tradeoffs involved in energy production. The first looks at transitioning marine vessels to natural gas from current distillate fuels. While natural gas will reduce local air pollutants, such as sulfur oxides and particulate matter, the implications for greenhouse gases depend on how the natural gas is extracted, processed, distributed, and used. Applying a "technology warming potential" (TWP) approach, natural gas as a marine fuel achieves climate parity within 30 years for diesel ignited engines, though it could take up to 190 years to reach climate parity with conventional fuels in a spark ignited engine. Movement towards natural gas as a marine fuel continues to progress, and conditions exist in some regions to make a near-term transition to natural gas feasible. The second study looks at externalities associated with electricity generation. The impact on the surrounding community is one concern when siting new electricity generating facilities. A survey was conducted of residents living near an industrial scale wind turbine and a coal-fired power plant to determine their visual and auditory effects on the residents. Results concluded that respondents living near the wind turbine were in favor of the facility. They were willing to pay an average of 2.56 a month to keep the turbine in its current location. Respondents living near the coal plant were opposed to the facility. They were willing to spend 1.82 a month to have the facility removed. The third study presents a cost effectiveness analysis of three of the main fuels used for electricity generation, namely coal, natural gas, and wind. This analysis adds social costs to the private costs traditionally utilized by investors making decisions. It utilizes previous research on visual and auditory amenity and disamenity values as well as recent published studies on the impacts of electricity generation on water use, wildlife, and property values, among others, as well as other impacts well documented in the literature. When literature values were not identical, low, medium, and high values were considered in order to look at the full range of values. On average, the cost of wind power is 0.0332/kWh, natural gas power is 0.1071/kWh, and coal $0.1314/kWh.

Lactate shuttling and lactate use as fuel after traumatic brain injury: metabolic considerations

PubMed Central

Dienel, Gerald A

2014-01-01

Lactate is proposed to be generated by astrocytes during glutamatergic neurotransmission and shuttled to neurons as ‘preferred' oxidative fuel. However, a large body of evidence demonstrates that metabolic changes during activation of living brain disprove essential components of the astrocyte–neuron lactate shuttle model. For example, some glutamate is oxidized to generate ATP after its uptake into astrocytes and neuronal glucose phosphorylation rises during activation and provides pyruvate for oxidation. Extension of the notion that lactate is a preferential fuel into the traumatic brain injury (TBI) field has important clinical implications, and the concept must, therefore, be carefully evaluated before implementation into patient care. Microdialysis studies in TBI patients demonstrate that lactate and pyruvate levels and lactate/pyruvate ratios, along with other data, have important diagnostic value to distinguish between ischemia and mitochondrial dysfunction. Results show that lactate release from human brain to blood predominates over its uptake after TBI, and strong evidence for lactate metabolism is lacking; mitochondrial dysfunction may inhibit lactate oxidation. Claims that exogenous lactate infusion is energetically beneficial for TBI patients are not based on metabolic assays and data are incorrectly interpreted. PMID:25204393

Economic implications of incorporating emission controls to mitigate air pollutants emitted from a modeled hydrocarbon-fuel biorefinery in the United States

DOE PAGES

Bhatt, Arpit; Zhang, Yimin; Davis, Ryan; ...

2016-07-15

The implementation of the US Renewable Fuel Standard is expected to increase the construction and operation of new biofuel facilities. Allowing this industry to grow without adversely affecting air quality is an important sustainability goal sought by multiple stakeholders. However, little is known about how the emission controls potentially required to comply with air quality regulations might impact biorefinery cost and deployment strategies such as siting and sizing. In this study, we use a baseline design for a lignocellulosic hydrocarbon biofuel production process to assess how the integration of emission controls impacts the minimum fuel selling price (MFSP) of themore » biofuel produced. We evaluate the change in MFSP for two cases as compared to the baseline design by incorporating (i) emission controls that ensure compliance with applicable federal air regulations and (ii) advanced control options that could be used to achieve potential best available control technology (BACT) emission limits. Our results indicate that compliance with federal air regulations can be achieved with minimal impact on biofuel cost (~$0.02 per gasoline gallon equivalent (GGE) higher than the baseline price of $5.10 GGE -1). However, if air emissions must be further reduced to meet potential BACT emission limits, the cost could increase nontrivially. For example, the MFSP could increase to $5.50 GGE -1 by adopting advanced emission controls to meet potential boiler BACT limits. Finally, given tradeoffs among emission control costs, permitting requirements, and economies of scale, these results could help inform decisions about biorefinery siting and sizing and mitigate risks associated with air permitting.« less

Understanding Potential Air Emissions from a Cellulosic Biorefinery Producing Renewable Diesel Blendstock.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yimin; Heath, Garvin A.; Renzaglia, Jason

2015-06-22

The Energy Independence and Security Act of 2007, through the Renewable Fuel Standard (RFS), mandates increased use of biofuels, including cellulosic biofuels. The RFS is expected to spur the development of advanced biofuel technologies (e.g., new and innovative biofuel conversion pathways) as well as the construction of biorefineries (refineries that produce biofuels) using these technologies. To develop sustainable cellulosic biofuels, one of the goals of the Bioenergy Technologies Office (BETO) at the Department of Energy is to minimize air pollutants from the entire biofuel supply chain, as stated in their 2014 Multi-Year Program Plan (2014). Although biofuels in general havemore » been found to have lower life cycle greenhouse gas (GHG) emissions compared to petroleum fuels on an energy basis, biomass feedstock production, harvesting, transportation, processing and conversion are expected to emit a wide range of other air pollutants (e.g., criteria air pollutants, hazardous air pollutants), which could affect the environmental benefits of biofuels when displacing petroleum fuels. While it is important for policy makers, air quality planners and regulators, biofuel developers, and investors to understand the potential implications on air quality from a growing biofuel industry, there is a general lack of information and knowledge about the type, fate and magnitude of potential air pollutant emissions from the production of cellulosic biofuels due to the nascent stage of this emerging industry. This analysis assesses potential air pollutant emissions from a hypothetical biorefinery, selected by BETO for further research and development, which uses a biological conversion process of sugars to hydrocarbons to produce infrastructural-compatible renewable diesel blendstock from cellulosic biomass.« less

The Environmental Protection Agency's Safety Standards for Disposal of Spent Nuclear Fuel: Potential Path Forward in Response to the Report of the Blue Ribbon Commission on America's Nuclear Future - 13388

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forinash, Betsy; Schultheisz, Daniel; Peake, Tom

2013-07-01

Following the decision to withdraw the Yucca Mountain license application, the Department of Energy created a Blue Ribbon Commission (BRC) on America's Nuclear Future, tasked with recommending a national strategy to manage the back end of the nuclear fuel cycle. The BRC issued its final report in January 2012, with recommendations covering transportation, storage and disposal of spent nuclear fuel (SNF); potential reprocessing; and supporting institutional measures. The BRC recommendations on disposal of SNF and high-level waste (HLW) are relevant to the U.S. Environmental Protection Agency (EPA), which shares regulatory responsibility with the Nuclear Regulatory Commission (NRC): EPA issues 'generallymore » applicable' performance standards for disposal repositories, which are then implemented in licensing. For disposal, the BRC endorses developing one or more geological repositories, with siting based on an approach that is adaptive, staged and consent-based. The BRC recommends that EPA and NRC work cooperatively to issue generic disposal standards-applying equally to all sites-early in any siting process. EPA previously issued generic disposal standards that apply to all sites other than Yucca Mountain. However, the BRC concluded that the existing regulations should be revisited and revised. The BRC proposes a number of general principles to guide the development of future regulations. EPA continues to review the BRC report and to assess the implications for Agency action, including potential regulatory issues and considerations if EPA develops new or revised generic disposal standards. This review also involves preparatory activities to define potential process and public engagement approaches. (authors)« less

Implications of Sustainability for the United States Light-Duty Transportation Sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gearhart, Chris

Climate change is a problem that must be solved. The primary cause of this problem is burning of fossil fuels to generate energy. A dramatic reduction in carbon emissions must happen soon, and a significant fraction of this reduction must come from the transportation sector. This paper reviews existing literature to assess the consensus of the scientific and engineering communities concerning the potential for the United States' light-duty transportation sector to meet a goal of 80 percent reduction in vehicle emissions and examine what it will take to meet this target. It is unlikely that reducing energy consumption in justmore » vehicles with gasoline-based internal combustion drivetrains will be sufficient to meet GHG emission-reduction targets. This paper explores what additional benefits are possible through the adoption of alternative energy sources, looking at three possible on-vehicle energy carriers: carbon-based fuels, hydrogen, and batteries. potential for the United States' light-duty transportation sector to meet a goal of 80 percent reduction in vehicle emissions and examine what it will take to meet this target. It is unlikely that reducing energy consumption in just vehicles with gasoline-based internal combustion drivetrains will be sufficient to meet GHG emission-reduction targets. This paper explores what additional benefits are possible through the adoption of alternative energy sources, looking at three possible on-vehicle energy carriers: carbon-based fuels, hydrogen, and batteries.« less

Disposal of spent fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blomeke, J O; Ferguson, D E; Croff, A G

1978-01-01

Based on preliminary analyses, spent fuel assemblies are an acceptable form for waste disposal. The following studies appear necessary to bring our knowledge of spent fuel as a final disposal form to a level comparable with that of the solidified wastes from reprocessing: 1. A complete systems analysis is needed of spent fuel disposition from reactor discharge to final isolation in a repository. 2. Since it appears desirable to encase the spent fuel assembly in a metal canister, candidate materials for this container need to be studied. 3. It is highly likely that some ''filler'' material will be needed betweenmore » the fuel elements and the can. 4. Leachability, stability, and waste-rock interaction studies should be carried out on the fuels. The major disadvantages of spent fuel as a disposal form are the lower maximum heat loading, 60 kW/acre versus 150 kW/acre for high-level waste from a reprocessing plant; the greater long-term potential hazard due to the larger quantities of plutonium and uranium introduced into a repository; and the possibility of criticality in case the repository is breached. The major advantages are the lower cost and increased near-term safety resulting from eliminating reprocessing and the treatment and handling of the wastes therefrom.« less

Preliminary fabrication and characterisation of inert matrix and thoria fuels for plutonium disposition in light water reactors

NASA Astrophysics Data System (ADS)

Vettraino, F.; Magnani, G.; La Torretta, T.; Marmo, E.; Coelli, S.; Luzzi, L.; Ossi, P.; Zappa, G.

1999-08-01

The plutonium disposition is presently acknowledged as a most urgent issue at the world level. Inert matrix and thoria fuel concepts for Pu burning in LWRs show good potential in providing effective and ultimate solutions to this issue. In non-fertile (U-free) inert matrix fuel, plutonium oxide is diluted within inert oxides such as stabilised ZrO 2, Al 2O 3, MgO or MgAl 2O 4. Thoria addition, which helps improve neutronic characteristics of inert fuels, appears as a promising variant of U-free fuel. In the context of an R&D activity aimed at assessing the feasibility of the fuel concept above, simulated fuel pellets have been produced both from dry-powder metallurgy and the sol-gel route. Results show that they can be fabricated by matching basic nuclear grade specifications such as the required geometry, density and microstructure. Some characterisation testing dealing with thermo-physical properties, ion irradiation damage and solubility also have been started. Results from thermo-physical measurements at room temperature have been achieved. A main feature stemming from solubility testing outcomes is a very high chemical stability which should render the fuel strongly diversion resistant and suitable for direct final disposal in deep geological repository (once-through solution).

The Potential of Different Concepts of Fast Breeder Reactor for the French Fleet Renewal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Massara, Simone; Tetart, Philippe; Lecarpentier, David

2006-07-01

The performances of different concepts of Fast Breeder Reactor (Na-cooled, He-cooled and Pb-cooled FBR) for the current French fleet renewal are analyzed in the framework of a transition scenario to a 100% FBR fleet at the end of the 21. century. Firstly, the modeling of these three FBR types by means of a semi-analytical approach in TIRELIRE - STRATEGIE, the EDF fuel cycle simulation code, is presented, together with some validation elements against ERANOS, the French reference code system for neutronic FBR analysis (CEA). Afterwards, performances comparisons are made in terms of maximum deployable power, natural uranium consumption and wastemore » production. The results show that the FBR maximum deployable capacity, independently from the FBR technology, is highly sensitive to the fuel cycle options, like the spent nuclear fuel cooling time or the Minor Actinides management strategy. Thus, some of the key parameters defining the dynamic of FBR deployment are highlighted, to inform the orientation of R and D in the development and optimization of these systems. (authors)« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Nicholas R.; Worrall, Andrew; Todosow, Michael

Small modular reactors (SMRs) offer potential benefits, such as enhanced operational flexibility. However, it is vital to understand the holistic impact of SMRs on nuclear fuel cycle performance. The focus of this paper is the fuel cycle impacts of light water SMRs in a once-through fuel cycle with low-enriched uranium fuel. A key objective of this paper is to describe preliminary example reactor core physics and fuel cycle analyses conducted in support of the U.S. Department of Energy, Office of Nuclear Energy, Fuel Cycle Options Campaign. The hypothetical light water SMR example case considered in these preliminary scoping studies ismore » a cartridge type one-batch core with slightly less than 5.0% enrichment. Challenges associated with SMRs include increased neutron leakage, fewer assemblies in the core (and therefore fewer degrees of freedom in the core design), complex enrichment and burnable absorber loadings, full power operation with inserted control rods, the potential for frequent load-following operation, and shortened core height. Each of these will impact the achievable discharge burnup in the reactor and the fuel cycle performance. This paper summarizes a list of the factors relevant to SMR fuel, core, and operation that will impact fuel cycle performance. The high-level issues identified and preliminary scoping calculations in this paper are intended to inform on potential fuel cycle impacts of one-batch thermal spectrum SMRs. In particular, this paper highlights the impact of increased neutron leakage and reduced number of batches on the achievable burnup of the reactor. Fuel cycle performance metrics for a hypothetical example SMR are compared with those for a conventional three-batch light water reactor in the following areas: nuclear waste management, environmental impact, and resource utilization. The metrics performance for such an SMR is degraded for the mass of spent nuclear fuel and high-level waste disposed of, mass of depleted uranium disposed of, land use per energy generated, and carbon emissions per energy generated. Finally, it is noted that the features of some SMR designs impact three main aspects of fuel cycle performance: (1) small cores which means high leakage (there is a radial and axial component), (2) no boron which means heterogeneous core and extensive use of control rods and BPs, and (3) single batch cores. But not all of the SMR designs have all of these traits. As a result, the approach used in this study is therefore a bounding case and not all SMRs may be affected to the same extent.« less

Climate Science and the Responsibilities of Fossil Fuel Companies for Climate Damages and Adaptation

NASA Astrophysics Data System (ADS)

Frumhoff, P. C.; Ekwurzel, B.

2017-12-01

Policymakers in several jurisdictions are now considering whether fossil fuel companies might bear some legal responsibility for climate damages and the costs of adaptation to climate change potentially traceable to the emissions from their marketed products. Here, we explore how scientific research, outreach and direct engagement with industry leaders and shareholders have informed and may continue to inform such developments. We present the results of new climate model research quantifying the contribution of carbon dioxide and methane emissions traced to individual fossil fuel companies to changes in global temperature and sea level; explore the impact of such research and outreach on both legal and broader societal consideration of company responsibility; and discuss the opportunities and challenges for scientists to engage in further work in this area.

Effect of Manganese on some aspects of carbohydrate metabolism in rats. [None

DOE Office of Scientific and Technical Information (OSTI.GOV)

Husain, R.; Mushtaq, M.; Seth, P.K.

1980-10-01

Numerous biochemical and toxicological studies have indicated that chronic exposure to manganese leads to neurological abnormalities. Increasing use of manganese compounds as antiknocks in gasoline and diesel fuel has aroused a great concern over the toxicological potential of this metal and stressed the need for understanding the mechanism of its poisoning. Reports of alerations in the levels of biogenic amines have helped in understanding the basis of neurological disorders. However, little is known about the mechanism by which manganese exposure leads to hypoglycemia in workers. This study deals with the influence of manganese exposure on metabolism of glucose, the chiefmore » fuel of the brain, and some enzymes involved in its oxidation. These studies will provide an assessment of the extent to which manganese affects the various processes controlling carbohydrate metabolism.« less

Light Truck Capabilities, Utility Requirements, and Uses : Implications for Fuel Economy. Final Report

DOT National Transportation Integrated Search

1996-04-01

In April 1994, NHTSA issued an Advanced Notice of Proposed Rule Making (ANPRM) requesting information regarding light truck fuel economy capabilities for model years 1998 through 2006. Subsequently, in the Department of Transportation Appropriations ...

Household income and vehicle fuel economy in California.

DOT National Transportation Integrated Search

2015-11-01

This white paper presents the findings from an analysis of the fiscal implications for vehicle owners of changing from the current : statewide fuel tax to a road user charge (RUC) based on vehicle-miles traveled (VMT). Since 1923, California...

The influence of multiple goals on driving behavior: the case of safety, time saving, and fuel saving.

PubMed

Dogan, Ebru; Steg, Linda; Delhomme, Patricia

2011-09-01

Due to the innate complexity of the task drivers have to manage multiple goals while driving and the importance of certain goals may vary over time leading to priority being given to different goals depending on the circumstances. This study aimed to investigate drivers' behavioral regulation while managing multiple goals during driving. To do so participants drove on urban and rural roads in a driving simulator while trying to manage fuel saving and time saving goals, besides the safety goals that are always present during driving. A between-subjects design was used with one group of drivers managing two goals (safety and fuel saving) and another group managing three goals (safety, fuel saving, and time saving) while driving. Participants were provided continuous feedback on the fuel saving goal via a meter on the dashboard. The results indicate that even when a fuel saving or time saving goal is salient, safety goals are still given highest priority when interactions with other road users take place and when interacting with a traffic light. Additionally, performance on the fuel saving goal diminished for the group that had to manage fuel saving and time saving together. The theoretical implications for a goal hierarchy in driving tasks and practical implications for eco-driving are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Elucidating secondary organic aerosol from diesel and gasoline vehicles through detailed characterization of organic carbon emissions

PubMed Central

Gentner, Drew R.; Isaacman, Gabriel; Worton, David R.; Chan, Arthur W. H.; Dallmann, Timothy R.; Davis, Laura; Liu, Shang; Day, Douglas A.; Russell, Lynn M.; Wilson, Kevin R.; Weber, Robin; Guha, Abhinav; Harley, Robert A.; Goldstein, Allen H.

2012-01-01

Emissions from gasoline and diesel vehicles are predominant anthropogenic sources of reactive gas-phase organic carbon and key precursors to secondary organic aerosol (SOA) in urban areas. Their relative importance for aerosol formation is a controversial issue with implications for air quality control policy and public health. We characterize the chemical composition, mass distribution, and organic aerosol formation potential of emissions from gasoline and diesel vehicles, and find diesel exhaust is seven times more efficient at forming aerosol than gasoline exhaust. However, both sources are important for air quality; depending on a region’s fuel use, diesel is responsible for 65% to 90% of vehicular-derived SOA, with substantial contributions from aromatic and aliphatic hydrocarbons. Including these insights on source characterization and SOA formation will improve regional pollution control policies, fuel regulations, and methodologies for future measurement, laboratory, and modeling studies. PMID:23091031

Aircraft borne combined measurements of the Fukushima radionuclide Xe-133 and fossil fuel combustion generated pollutants in the TIL - Implications for Cyclone induced lift and TIL physical-chemical processes

NASA Astrophysics Data System (ADS)

Arnold, Frank; Schlager, Hans; Simgen, Hardy; Aufmhoff, Heinfried; Baumann, Robert; Lindemann, Sigfried; Rauch, Ludwig; Kaether, Frank; Pirjolla, Liisa; Schumann, Ulrich

2013-04-01

The radionuclide Xe-133, released by the March 2011 nuclear disaster at Fukushima/Daiichi (hereafter FD), represents an ideal tracer for atmospheric transport. We report the, to our best knowledge, only aircraft borne measurements of FD Xe-133 in the Tropopause Inversion Layer (TIL), indicating rapid lift of Xe-133 rich planetary boundary layer air to the TIL. On the same research aircraft (FALCON), we have also conducted on-line measurements of fossil fuel combustion generated pollutant gases (SO2, NOx, HNO3,NOy), which were found to have increased concentrations in the TIL. In addition, we have conducted supporting model simulations of transport, chemical processes, and aerosol processes. Our investigations reveal a potentially important influence of East-Asian cyclone induced pollutants transport to the TIL, particularly influencing aerosol formation in the TIL.

Occupational exposure to hydrazines: treatment of acute central nervous system toxicity.

PubMed

Zelnick, Sanford D; Mattie, David R; Stepaniak, Philip C

2003-12-01

Exposure to hydrazine and hydrazines' alkylated derivatives is an important occupational health issue, which will increase in significance as space applications increase. Despite their widespread usage as rocket fuels in manned and unmanned space and missile systems, serious exposures to hydrazines are rare. While a significant number of experimental studies were performed in the late 1950s through the mid-1960s, conflicting information exists concerning the most appropriate treatment for these exposures. A cross-sectional study evaluating the most common rocket fuels such as hydrazine; 1,1-dimethylhydrazine (UDMH); mono-methylhydrazine (MMH); and Aerozine-50 against the most commonly suggested therapies, such as pyridoxine, traditional antiseizure therapies, and arginine is needed to clarify the treatment implications for human exposure. Treatments that have been useful for hyperammonemic states, such as those for the six inherited urea cycle defects, have significant potential for the improvement of hydrazine exposure treatment.

Elucidating secondary organic aerosol from diesel and gasoline vehicles through detailed characterization of organic carbon emissions.

PubMed

Gentner, Drew R; Isaacman, Gabriel; Worton, David R; Chan, Arthur W H; Dallmann, Timothy R; Davis, Laura; Liu, Shang; Day, Douglas A; Russell, Lynn M; Wilson, Kevin R; Weber, Robin; Guha, Abhinav; Harley, Robert A; Goldstein, Allen H

2012-11-06

Emissions from gasoline and diesel vehicles are predominant anthropogenic sources of reactive gas-phase organic carbon and key precursors to secondary organic aerosol (SOA) in urban areas. Their relative importance for aerosol formation is a controversial issue with implications for air quality control policy and public health. We characterize the chemical composition, mass distribution, and organic aerosol formation potential of emissions from gasoline and diesel vehicles, and find diesel exhaust is seven times more efficient at forming aerosol than gasoline exhaust. However, both sources are important for air quality; depending on a region's fuel use, diesel is responsible for 65% to 90% of vehicular-derived SOA, with substantial contributions from aromatic and aliphatic hydrocarbons. Including these insights on source characterization and SOA formation will improve regional pollution control policies, fuel regulations, and methodologies for future measurement, laboratory, and modeling studies.

Transportation Energy Futures Series. Projected Biomass Utilization for Fuels and Power in a Mature Market

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruth, M.; Mai, T.; Newes, E.

2013-03-01

The viability of biomass as transportation fuel depends upon the allocation of limited resources for fuel, power, and products. By focusing on mature markets, this report identifies how biomass is projected to be most economically used in the long term and the implications for greenhouse gas (GHG) emissions and petroleum use. In order to better understand competition for biomass between these markets and the potential for biofuel as a market-scale alternative to petroleum-based fuels, this report presents results of a micro-economic analysis conducted using the Biomass Allocation and Supply Equilibrium (BASE) modeling tool. The findings indicate that biofuels can outcompetemore » biopower for feedstocks in mature markets if research and development targets are met. The BASE tool was developed for this project to analyze the impact of multiple biomass demand areas on mature energy markets. The model includes domestic supply curves for lignocellulosic biomass resources, corn for ethanol and butanol production, soybeans for biodiesel, and algae for diesel. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Transportation Energy Futures Series: Projected Biomass Utilization for Fuels and Power in a Mature Market

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruth, M.; Mai, T.; Newes, E.

2013-03-01

The viability of biomass as transportation fuel depends upon the allocation of limited resources for fuel, power, and products. By focusing on mature markets, this report identifies how biomass is projected to be most economically used in the long term and the implications for greenhouse gas (GHG) emissions and petroleum use. In order to better understand competition for biomass between these markets and the potential for biofuel as a market-scale alternative to petroleum-based fuels, this report presents results of a micro-economic analysis conducted using the Biomass Allocation and Supply Equilibrium (BASE) modeling tool. The findings indicate that biofuels can outcompetemore » biopower for feedstocks in mature markets if research and development targets are met. The BASE tool was developed for this project to analyze the impact of multiple biomass demand areas on mature energy markets. The model includes domestic supply curves for lignocellulosic biomass resources, corn for ethanol and butanol production, soybeans for biodiesel, and algae for diesel. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Polycyclic Aromatic Hydrocarbon Exposure in Household Air Pollution from Solid Fuel Combustion among the Female Population of Xuanwei and Fuyuan Counties, China

PubMed Central

2015-01-01

Exposure to polycyclic aromatic hydrocarbons (PAHs) from burning “smoky” (bituminous) coal has been implicated as a cause of the high lung cancer incidence in the counties of Xuanwei and Fuyuan, China. Little is known about variations in PAH exposure from throughout the region nor how fuel source and stove design affects exposure. Indoor and personal PAH exposure resulting from solid fuel combustion in Xuanwei and Fuyuan was investigated using repeated 24 h particle bound and gas-phase PAH measurements, which were collected from 163 female residents of Xuanwei and Fuyuan. 549 particle bound (283 indoor and 266 personal) and 193 gas phase (all personal) PAH measurements were collected. Mixed effect models indicated that PAH exposure was up to 6 times higher when burning smoky coal than smokeless coal and varied by up to a factor of 3 between different smoky coal geographic sources. PAH measurements from unventilated firepits were up to 5 times that of ventilated stoves. Exposure also varied between different room sizes and season of measurement. These findings indicate that PAH exposure is modulated by a variety of factors, including fuel type, coal source, and stove design. These findings may provide valuable insight into potential causes of lung cancer in the area. PMID:25393345

Potential for Electrified Vehicles to Contribute to U.S. Petroleum and Climate Goals and Implications for Advanced Biofuels.

PubMed

Meier, Paul J; Cronin, Keith R; Frost, Ethan A; Runge, Troy M; Dale, Bruce E; Reinemann, Douglas J; Detlor, Jennifer

2015-07-21

To examine the national fuel and emissions impacts from increasingly electrified light-duty transportation, we reconstructed the vehicle technology portfolios from two national vehicle studies. Using these vehicle portfolios, we normalized assumptions and examined sensitivity around the rates of electrified vehicle penetration, travel demand growth, and electricity decarbonization. We further examined the impact of substituting low-carbon advanced cellulosic biofuels in place of petroleum. Twenty-seven scenarios were benchmarked against a 50% petroleum-reduction target and an 80% GHG-reduction target. We found that with high rates of electrification (40% of miles traveled) the petroleum-reduction benchmark could be satisfied, even with high travel demand growth. The same highly electrified scenarios, however, could not satisfy 80% GHG-reduction targets, even assuming 80% decarbonized electricity and no growth in travel demand. Regardless of precise consumer vehicle preferences, emissions are a function of the total reliance on electricity versus liquid fuels and the corresponding greenhouse gas intensities of both. We found that at a relatively high rate of electrification (40% of miles and 26% by fuel), an 80% GHG reduction could only be achieved with significant quantities of low-carbon liquid fuel in cases with low or moderate travel demand growth.

Heat Source Characterization In A TREAT Fuel Particle Using Coupled Neutronics Binary Collision Monte-Carlo Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schunert, Sebastian; Schwen, Daniel; Ghassemi, Pedram

This work presents a multi-physics, multi-scale approach to modeling the Transient Test Reactor (TREAT) currently prepared for restart at the Idaho National Laboratory. TREAT fuel is made up of microscopic fuel grains (r ˜ 20µm) dispersed in a graphite matrix. The novelty of this work is in coupling a binary collision Monte-Carlo (BCMC) model to the Finite Element based code Moose for solving a microsopic heat-conduction problem whose driving source is provided by the BCMC model tracking fission fragment energy deposition. This microscopic model is driven by a transient, engineering scale neutronics model coupled to an adiabatic heating model. Themore » macroscopic model provides local power densities and neutron energy spectra to the microscpic model. Currently, no feedback from the microscopic to the macroscopic model is considered. TREAT transient 15 is used to exemplify the capabilities of the multi-physics, multi-scale model, and it is found that the average fuel grain temperature differs from the average graphite temperature by 80 K despite the low-power transient. The large temperature difference has strong implications on the Doppler feedback a potential LEU TREAT core would see, and it underpins the need for multi-physics, multi-scale modeling of a TREAT LEU core.« less

FCRD Transmutation Fuels Handbook 2015

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janney, Dawn Elizabeth; Papesch, Cynthia Ann

2015-09-01

Transmutation of minor actinides such as Np, Am, and Cm in spent nuclear fuel is of international interest because of its potential for reducing the long-term health and safety hazards caused by the radioactivity of the spent fuel. One important approach to transmutation (currently being pursued by the DOE Fuel Cycle Research & Development Advanced Fuels Campaign) involves incorporating the minor actinides into U-Pu-Zr alloys, which can be used as fuel in fast reactors. It is, therefore, important to understand the properties of U-Pu-Zr alloys, both with and without minor actinide additions. In addition to requiring extensive safety precautions, alloysmore » containing U and Pu are difficult to study for numerous reasons, including their complex phase transformations, characteristically sluggish phase-transformation kinetics, tendency to produce experimental results that vary depending on the histories of individual samples, and sensitivity to contaminants such as oxygen in concentrations below a hundred parts per million. Many of the experimental measurements were made before 1980, and the level of documentation for experimental methods and results varies widely. It is, therefore, not surprising that little is known with certainty about U-Pu-Zr alloys, and that general acceptance of results sometimes indicates that there is only a single measurement for a particular property. This handbook summarizes currently available information about U, Pu, Zr, and alloys of two or three of these elements. It contains information about phase diagrams and related information (including phases and phase transformations); heat capacity, entropy, and enthalpy; thermal expansion; and thermal conductivity and diffusivity. In addition to presenting information about materials properties, it attempts to provide information about how well the property is known and how much variation exists between measurements. Although the handbook includes some references to publications about modeling, its primary focus is experimental data. Most of the data has been published elsewhere (although scattered throughout numerous references, some quite obscure); however, some data is presented here for the first time.« less

Modeling Fire Emissions across Central and Southern Italy: Implications for Land and Fire Management

NASA Astrophysics Data System (ADS)

Bacciu, V. M.; Salis, M.; Spano, D.

2015-12-01

Fires play a relevant role in the global and regional carbon cycle, representing a remarkable source of CO2 and other greenhouse gases (GHG) that influence atmosphere budgets and climate. In addition, the wildfire increase projected in Southern Europe due to climate change (CC) and concurrent exacerbation of extreme weather conditions could also lead to a significant rise in GHG. Recently, in the context of the Italian National Adaptation Strategy to Climate Change (SNAC), several approaches were identified as valuable tools to adapt and mitigate the impacts of CC on wildfires, in order to reduce landscape susceptibility and to contribute to the efforts of carbon emission mitigation proposed within the Kyoto protocol. Active forest and fuel management (such as prescribed burning, fuel reduction and removal, weed and flammable shrub control, creation of fuel discontinuity) is recognised to be a key element to adapt and mitigate the impacts of CC on wildfires. Despite this, overall there is a lack of studies about the effectiveness of fire emission mitigation strategies. The current work aims to analyse the potential of a combination of fuel management practices in mitigating emissions from forest fires and evaluate valuable and viable options across Central and Southern Italy. These objectives were achieved throughout a retrospective application of an integrated approach combining a fire emission model (FOFEM - First Order Fire Effect Model) with spatially explicit, comprehensive, and accurate fire, vegetation and weather data for the period 2004-2012. Furthermore, a number of silvicultural techniques were combined to develop several fuel management scenarios and then tested to evaluate their potential in mitigating fire emissions.The preliminary results showed the crucial role of appropriate fuel, fire behavior, and weather data to reduce bias in quantifying the source and the composition of fire emissions and to attain reasonable estimations. Also, the current study highlighted that balanced combination of fuel management techniques could not only be a viable mean to reduce fire emissions but at the same time prevent future wildfires and the related threat to human lives and activities.

The Contribution of Black Carbon to Ice Nucleating Particle Concentrations from Prescribed Burns and Wildfires

NASA Astrophysics Data System (ADS)

Schill, G. P.; DeMott, P. J.; Suski, K. J.; Emerson, E. W.; Rauker, A. M.; Kodros, J.; Levin, E. J.; Hill, T. C. J.; Farmer, D.; Pierce, J. R.; Kreidenweis, S. M.

2017-12-01

Black carbon (BC) has been implicated as a potential immersion-mode ice nucleating particle (INP) because of its relative abundance in the upper troposphere. Furthermore, several field and aircraft measurements have observed positive correlations between BC and INP concentrations. Despite this, the efficiency of BC to act as an immersion-mode INP is poorly constrained. Indeed, previous results from laboratory studies are in conflict, with estimates of BC's impact on INP ranging from no impact to being efficient enough to rival the well-known INP mineral dust. It is, however, becoming clear that the ice nucleation activity of BC may depend on both its fuel type and combustion conditions. For example, previous work has shown that diesel exhaust BC is an extremely poor immersion-mode INP, but laboratory burns of biomass fuels indicate that BC can contribute up to 70% of all INP for some fuel types. Given these dependencies, we propose that sampling from real-world biomass burning sources would provide the most useful new information on the contribution of BC to atmospheric INP. In this work, we will present recent results looking at the sources of INP from prescribed burns and wildfires. To determine the specific contribution of refractory black carbon (rBC) to INP concentrations, we utilized a new technique that couples the Single Particle Soot Photometer (SP2) to the Colorado State University Continuous Flow Diffusion Chamber (CFDC). The SP2 utilizes laser-induced incandescence to quantify rBC mass on a particle-by-particle basis; in doing so, it also selectively destroys rBC particles by heating them to their vaporization temperature. Thus, the SP2 can be used as a selective pre-filter for rBC into the CFDC. Furthermore, we have also used a filter-based technique for measuring INP, the Ice Spectrometer, which can employ pretreatments such as heating and digestion by H2O2 to determine the contribution of heat-labile and organic particles, respectively.

Overview of the U.S. DOE Accident Tolerant Fuel Development Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jon Carmack; Frank Goldner; Shannon M. Bragg-Sitton

2013-09-01

The United States Fuel Cycle Research and Development Advanced Fuels Campaign has been given the responsibility to conduct research and development on enhanced accident tolerant fuels with the goal of performing a lead test assembly or lead test rod irradiation in a commercial reactor by 2022. The Advanced Fuels Campaign has defined fuels with enhanced accident tolerance as those that, in comparison with the standard UO2-Zircaloy system currently used by the nuclear industry, can tolerate loss of active cooling in the reactor core for a considerably longer time period (depending on the LWR system and accident scenario) while maintaining ormore » improving the fuel performance during normal operations and operational transients, as well as design-basis and beyond design-basis events. This paper provides an overview of the FCRD Accident Tolerant Fuel program. The ATF attributes will be presented and discussed. Attributes identified as potentially important to enhance accident tolerance include reduced hydrogen generation (resulting from cladding oxidation), enhanced fission product retention under severe accident conditions, reduced cladding reaction with high-temperature steam, and improved fuel-cladding interaction for enhanced performance under extreme conditions. To demonstrate the enhanced accident tolerance of candidate fuel designs, metrics must be developed and evaluated using a combination of design features for a given LWR design, potential improvements to that design, and the design of an advanced fuel/cladding system. The aforementioned attributes provide qualitative guidance for parameters that will be considered for fuels with enhanced accident tolerance. It may be unnecessary to improve in all attributes and it is likely that some attributes or combination of attributes provide meaningful gains in accident tolerance, while others may provide only marginal benefits. Thus, an initial step in program implementation will be the development of quantitative metrics. A companion paper in these proceedings provides an update on the status of establishing these quantitative metrics for accident tolerant LWR fuel.1 The United States FCRD Advanced Fuels Campaign has embarked on an aggressive schedule for development of enhanced accident tolerant LWR fuels. The goal of developing such a fuel system that can be deployed in the U.S. LWR fleet in the next 10 to 20 years supports the sustainability of clean nuclear power generation in the United States.« less

Catalytic partial oxidation reforming of hydrocarbon fuels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmed, S.

1998-09-21

The polymer electrolyte fuel cell (PEFC) is the primary candidate as the power source for light-duty transportation systems. On-board conversion of fuels (reforming) to supply the required hydrogen has the potential to provide the driving range that is typical of today's automobiles. Petroleum-derived fuels, gasoline or some distillate similar to it, are attractive because of their existing production, distribution, and retailing infrastructure. The fuel may be either petroleum-derived or other alternative fuels such as methanol, ethanol, natural gas, etc. [1]. The ability to use a variety of fuels is also attractive for stationary distributed power generation [2], such as inmore » buildings, or for portable power in remote locations. Argonne National Laboratory has developed a catalytic reactor based on partial oxidation reforming that is suitable for use in light-duty vehicles powered by fuel cells. The reactor has shown the ability to convert a wide variety of fuels to a hydrogen-rich gas at less than 800 C, temperatures that are several hundreds of degrees lower than alternative noncatalytic processes. The fuel may be methanol, ethanol, natural gas, or petroleum-derived fuels that are blends of various hydrocarbons such as paraffins, olefins, aromatics, etc., as in gasoline. This paper will discuss the results obtained from a bench-scale (3-kWe) reactor., where the reforming of gasoline and natural gas generated a product gas that contained 38% and 42% hydrogen on a dry basis at the reformer exit, respectively.« less

Investigation of the environmental implications of the CNT switch through its life cycle

NASA Astrophysics Data System (ADS)

Dahlben, Lindsay Johanna

Carbon nanotubes (CNTs) are unique allotropes of carbon that have high tensile strength, a high Young's modulus, good thermal conductivity, and depending on the CNT chirality can be metallic or semiconducting. These mechanical, thermal, and electrical properties make CNTs an attractive element in electronic applications such as conductive films, photovoltaics, non-volatile memory devices, batteries, sensors, and displays. Although commercialization of CNT-enabled products is increasing, there remains a significant lack of information regarding the health effects and environmental impacts of CNTs. Some studies have even shown that the behavior, toxicity, and persistence of CNTs may differ from bulk heterogeneous carbon. Given these uncertainties, it is prudent to assess the environmental attributes of CNT products and processes now to discover and potentially prevent adverse effects. This study investigates the environmental implications of a non-volatile bi-stable electromechanical CNT switch through its life cycle. Life cycle assessment (LCA) methodology is used to track the environmental impacts of the CNT switch through its fabrication and expected use and end-of-life (EOL) stages. Process parameters, energy consumption, input materials, output emissions, and yield efficiencies are determined for the laboratory and full-scale manufacture environments. The Ecoinvent(TM) inventory database and Eco-indicator 1999(TM) method are utilized for the impact assessment. Results for the fabrication stage are reported for highest contributions to environmental impact such as airborne inorganics, land use, and fossil fuels due to Au refining processes and electricity consumption. Extension of the LCA scope is evaluated for the potential replacement of CNT switches to current field-effect transistors (FETs) in flash memory for a cellular phone application. First-order predictions are made for the functionality and performance of the CNT switch during the use stage through an environmental perspective. Existing cellular phone EOL management options including recycling and direct disposal to landfill and incineration are evaluated for potential limitations, concerns, and environmental releases that may occur from the assimilation of CNT switch-enabled phones into the waste stream. In this manner, potential environmental effects of the CNT switch throughout its life cycle stages can be addressed alongside its technological development to ensure safe, sustainable, and successful CNT products.

Analysis of Cyclic Variability of Heat Release for High-EGR GDI Engine Operation with Observations on Implications for Effective Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaul, Brian C; Wagner, Robert M; Green Jr, Johney Boyd

2013-01-01

Operation of spark-ignition (SI) engines with high levels of charge dilution through exhaust gas recirculation (EGR) achieves significant engine efficiency gains while maintaining stoichiometric operation for compatibility with three-way catalysts. Dilution levels, however, are limited by cyclic variability-including significant numbers of misfires-that becomes more pronounced with increasing dilution. This variability has been shown to have both stochastic and deterministic components. Stochastic effects include turbulence, mixing variations, and the like, while the deterministic effect is primarily due to the nonlinear dependence of flame propagation rates and ignition characteristics on the charge composition, which is influenced by the composition of residual gasesmore » from prior cycles. The presence of determinism implies that an increased understanding the dynamics of such systems could lead to effective control approaches that allow operation near the edge of stability, effectively extending the dilution limit. This nonlinear dependence has been characterized previously for homogeneous charge, port fuel-injected (PFI) SI engines operating fuel-lean as well as with inert diluents such as bottled N2 gas. In this paper, cyclic dispersion in a modern boosted gasoline direct injection (GDI) engine using a cooled external EGR loop is examined, and the potential for improvement with effective control is evaluated through the use of symbol sequence statistics and other techniques from chaos theory. Observations related to the potential implications of these results for control approaches that could effectively enable engine operation at the edge of combustion stability are noted.« less

Eco-hydrological Controls on Litter Moisture Dynamics in Complex Terrain: Implications for Fuel Moisture and Fire Regimes in Temperate Forests

NASA Astrophysics Data System (ADS)

Nyman, P.; Duff, T. J.; Sheridan, G. J.

2016-12-01

Moisture content in litter on the forest floor can control ignition and spread of forest fires. The micrometeorological factors driving variation in litter moisture at the landscape scale are poorly understood, particularly in areas with heterogeneous vegetation and complex terrain. In this research we seek to quantify how climate, vegetation and eco-hydrological feedbacks contribute to variation in net radiation and potential evaporation at the forest floor. Research sites were established at 12 locations in southeast Australia with variable precipitation, solar exposure, and drainage areas. Forests ranged from open woodland to tall temperate forests. We measured solar radiation, air temperature, relative humidity, litter moisture, soil moisture, and litter temperature. Forest structure was characterised using hemispherical photos and LIDAR. Using these data on microclimate and vegetation structure we parameterise a model of daily potential evaporation at the forest floor. Results show that variation in evaporation rates from litter is driven by net radiation and the role of vapour pressure deficit is almost negligible due to high aerodynamic resistance. In open woodlands the net radiation is directly related to short-wave radiation and evaporation remains high despite low temperatures. In the tall wet forests, commonly found along drainage lines and on slopes with polar-facing aspects, the long-wave radiation was just as important as the shortwave radiation. Air temperature is therefore important in determining the flammability of these more productive forests. By implication, in complex terrain with heterogeneous forests, the temperature in the wet parts of the landscape is important in controlling connectivity of fuels and large-scale fire activity.

Tools Developed to Prepare and Stabilize Reactor Spent Fuel for Retrieval from Tile Holes - 12251

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horne, Michael; Clough, Malcolm

Spent fuel from the Chalk River Laboratories (CRL) nuclear reactors is stored in the waste management areas on site. This fuel is contained within carbon steel spent fuel cans that are stored inside vertical carbon steel lined concrete pipes in the ground known as tile holes. The fuel cans have been stored in the tile holes for greater than 30 years. Some of the fuel cans have experienced corrosion which may have affected their structural integrity as well as the potential to form hydrogen gas. In addition to these potential hazards, there was a need to clean contaminated surfaces insidemore » of and around the exposed upper surface of the tile holes. As part of the site waste management remediation plan spent fuel will be retrieved from degraded tile holes, dried, and relocated to a new purpose built above ground storage facility. There have been a number of tools that are required to be developed to ensure spent fuel cans are in a safe condition prior to retrieval and re-location. A series of special purpose tools have been designed and constructed to stabilize the contents of the tile holes, to determine the integrity of the fuel containers and to decontaminate inside and around the tile holes. Described herein are the methods and types of tools used. Tools that have been presented here have been used, or will be used in the near future, in the waste management areas of the CRL Site in preparation for storage of spent fuel in a new above ground facility. The stabilization tools have been demonstrated on mock-up facilities prior to successful use in the field to remove hydrogen gas and uranium hydrides from the fuel cans. A lifting tool has been developed and used successfully in the field to confirm the integrity of the fuel cans for future relocation. A tool using a commercial dry ice blaster has been developed and is ready to start mock-up trials and is scheduled to be used in the field during the summer of 2012. (authors)« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Calvin, Katherine V.; Wise, Marshall A.; Kyle, G. Page

Many papers have shown that bioenergy and land-use are potentially important elements in a strategy to limit anthropogenic climate change. But, significant expansion of bioenergy production can have a large terrestrial footprint. In this paper, we test the implications for land use, the global energy system, carbon cycle, and carbon prices of meeting a specific climate target, using a single fossil fuel and industrial sector policy instrument—the carbon tax, but with five alternative bioenergy and land-use policy architectures. We find that the policies we examined have differing effects on the different segments of the economy. Comprehensive land policies can reducemore » land-use change emissions, increasing allowable emissions in the energy system, but have implications for the cost of food. Bioenergy taxes and constraints, on the other hand, have little effect on food prices, but can result in increased carbon and energy prices.« less

A STUDY OF THE DISCREPANCY BETWEEN FEDERAL AND STATE MEASUREMENTS OF ON-HIGHWAY FUEL CONSUMPTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, HL

2003-08-11

Annual highway fuel taxes are collected by the Treasury Department and placed in the Highway Trust Fund (HTF). There is, however, no direct connection between the taxes collected by the Treasury Department and the gallons of on-highway fuel use, which can lead to a discrepancy between these totals. This study was conducted to determine how much of a discrepancy exists between the total fuel usages estimated based on highway revenue funds as reported by the Treasury Department and the total fuel usages used in the apportionment of the HTF to the States. The analysis was conducted using data from Highwaymore » Statistics Tables MF-27 and FE-9 for the years 1991-2001. It was found that the overall discrepancy is relatively small, mostly within 5% difference. The amount of the discrepancy varies from year to year and varies among the three fuel types (gasoline, gasohol, special fuels). Several potential explanations for these discrepancies were identified, including issues on data, tax measurement, gallon measurement, HTF receipts, and timing. Data anomalies caused by outside forces, such as deferment of tax payments from one fiscal year to the next, can skew fuel tax data. Fuel tax evasion can lead to differences between actual fuel use and fuel taxes collected. Furthermore, differences in data collection and reporting among States can impact fuel use data. Refunds, credits, and transfers from the HTF can impact the total fuel tax receipt data. Timing issues, such as calendar year vs. fiscal year, can also cause some discrepancy between the two data sources.« less

Climate Forcing Growth Rates: Doubling Down on Our Faustian Bargain

NASA Technical Reports Server (NTRS)

Hansen, James; Kharecha, Pushker; Sato, Makiko

2013-01-01

Rahmstorf et al 's (2012) conclusion that observed climate change is comparable to projections, and in some cases exceeds projections, allows further inferences if we can quantify changing climate forcings and compare those with projections. The largest climate forcing is caused by well-mixed long-lived greenhouse gases. Here we illustrate trends of these gases and their climate forcings, and we discuss implications. We focus on quantities that are accurately measured, and we include comparison with fixed scenarios, which helps reduce common misimpressions about how climate forcings are changing. Annual fossil fuel CO2 emissions have shot up in the past decade at about 3/yr, double the rate of the prior three decades (figure 1). The growth rate falls above the range of the IPCC (2001) 'Marker' scenarios, although emissions are still within the entire range considered by the IPCC SRES (2000). The surge in emissions is due to increased coal use (blue curve in figure 1), which now accounts for more than 40 of fossil fuel CO2 emissions.

Evaluating and Addressing Potential Hazards of Fuel Tanks Surviving Atmospheric Reentry

NASA Technical Reports Server (NTRS)

Kelley, Robert L.; Johnson, Nicholas L.

2011-01-01

In order to ensure reentering spacecraft do not pose an undue risk to the Earth's population it is important to design satellites and rocket bodies with end of life considerations in mind. In addition to considering the possible consequences of deorbiting a vehicle, consideration must also be given to the possible risks associated with a vehicle failing to become operational or reach its intended orbit. Based on recovered space debris and numerous reentry survivability analyses, fuel tanks are of particular concern in both of these considerations. Most spacecraft utilize some type of fuel tank as part of their propulsion system. These fuel tanks are most often constructed using stainless steel or titanium and are filled with potentially hazardous substances such as hydrazine and nitrogen tetroxide. For a vehicle which has reached its scheduled end of mission the contents of the tanks are typically depleted. In this scenario the use of stainless steel and titanium results in the tanks posing a risk to people and property do to the high melting point and large heat of ablation of these materials leading to likely survival of the tank during reentry. If a large portion of the fuel is not depleted prior to reentry, there is the added risk of hazardous substance being released when the tank impact the ground. This paper presents a discussion of proactive methods which have been utilized by NASA satellite projects to address the risks associated with fuel tanks reentering the atmosphere. In particular it will address the design of a demiseable fuel tank as well as the evaluation of off the shelf designs which are selected to burst during reentry.

Potential Air Pollutant Emissions and Permitting Classifications for Two Biorefinery Process Designs in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eberle, Annika; Bhatt, Arpit; Zhang, Yimin

Advanced biofuel production facilities (biorefineries), such as those envisioned by the United States (U.S.) Renewable Fuel Standard and U.S. Department of Energy's research and development programs, often lack historical air pollutant emissions data, which can pose challenges for obtaining air emission permits that are required for construction and operation. To help fill this knowledge gap, we perform a thorough regulatory analysis and use engineering process designs to assess the applicability of federal air regulations and quantify air pollutant emissions for two feasibility-level biorefinery designs. We find that without additional emission-control technologies both biorefineries would likely be required to obtain majormore » source permits under the Clean Air Act's New Source Review program. The permitting classification (so-called 'major' or 'minor') has implications for the time and effort required for permitting and therefore affects the cost of capital and the fuel selling price. Consequently, we explore additional technically feasible emission-control technologies and process modifications that have the potential to reduce emissions to achieve a minor source permitting classification. Finally, our analysis of air pollutant emissions and controls can assist biorefinery developers with the air permitting process and inform regulatory agencies about potential permitting pathways for novel biorefinery designs.« less

Health and safety implications of alternative energy technologies. I. Geothermal and biomass

NASA Astrophysics Data System (ADS)

Watson, A. P.; Etnier, E. L.

1981-07-01

An evaluation of potential occupational and public health aspects of geopressure, hydrothermal, hot dry rock, silviculture, crop and animal residues, fermentable plant products, municipal waste, and plantation energy technologies has been performed. Future development of these energy options in the United States will contain hazards that could easily be eliminated by safer equipment design and common-sense attention to operation and maintenance. Occupational exposure to hydrogen sulfide gas occurs near all geothermal sites and wherever organic matter decomposes anaerobically. Respiratory damage has occurred to laborers in geothermal fields, while farm workers have been fatally overcome when employed near agitating liquid manure systems. However, the most frequent and severe of reported injuries to geothermal workers is dermal exposure to caustic sludges produced by H2S abatement systems. Principal health and safety considerations of biomass pathways are directly related to the diffuse nature of solar energy fixation by photosynthesis and subsequent transfer to animal food chains. Since the potential fuel is in an unconcentrated form, cultivation, harvest, and transport are necessarily laborintensive. Thus, a significant potential for occupational injuries and fatalities exists. Of all biomass systems evaluated, direct burning of solid fuels presents the greatest public health risk. Data are presented to characterize the population at risk and the frequency and severity of injuries.

Potential Air Pollutant Emissions and Permitting Classifications for Two Biorefinery Process Designs in the United States

DOE PAGES

Eberle, Annika; Bhatt, Arpit; Zhang, Yimin; ...

2017-04-26

Advanced biofuel production facilities (biorefineries), such as those envisioned by the United States (U.S.) Renewable Fuel Standard and U.S. Department of Energy's research and development programs, often lack historical air pollutant emissions data, which can pose challenges for obtaining air emission permits that are required for construction and operation. To help fill this knowledge gap, we perform a thorough regulatory analysis and use engineering process designs to assess the applicability of federal air regulations and quantify air pollutant emissions for two feasibility-level biorefinery designs. We find that without additional emission-control technologies both biorefineries would likely be required to obtain majormore » source permits under the Clean Air Act's New Source Review program. The permitting classification (so-called 'major' or 'minor') has implications for the time and effort required for permitting and therefore affects the cost of capital and the fuel selling price. Consequently, we explore additional technically feasible emission-control technologies and process modifications that have the potential to reduce emissions to achieve a minor source permitting classification. Finally, our analysis of air pollutant emissions and controls can assist biorefinery developers with the air permitting process and inform regulatory agencies about potential permitting pathways for novel biorefinery designs.« less

Potential Air Pollutant Emissions and Permitting Classifications for Two Biorefinery Process Designs in the United States.

PubMed

Eberle, Annika; Bhatt, Arpit; Zhang, Yimin; Heath, Garvin

2017-06-06

Advanced biofuel production facilities (biorefineries), such as those envisioned by the United States (U.S.) Renewable Fuel Standard and U.S. Department of Energy's research and development programs, often lack historical air pollutant emissions data, which can pose challenges for obtaining air emission permits that are required for construction and operation. To help fill this knowledge gap, we perform a thorough regulatory analysis and use engineering process designs to assess the applicability of federal air regulations and quantify air pollutant emissions for two feasibility-level biorefinery designs. We find that without additional emission-control technologies both biorefineries would likely be required to obtain major source permits under the Clean Air Act's New Source Review program. The permitting classification (so-called "major" or "minor") has implications for the time and effort required for permitting and therefore affects the cost of capital and the fuel selling price. Consequently, we explore additional technically feasible emission-control technologies and process modifications that have the potential to reduce emissions to achieve a minor source permitting classification. Our analysis of air pollutant emissions and controls can assist biorefinery developers with the air permitting process and inform regulatory agencies about potential permitting pathways for novel biorefinery designs.

An Assessment of the Challenges Associated with Individual Battlefield Power: Addressing the Power Budget Burdens of the Warfighter and Squad

DTIC Science & Technology

2014-05-01

Fuel Cells —JP8 Fuel Cells Aerial ResupplyBATMAN Advanced Battery Technologies Conformal Battery Nett Warrior Carried C-IED N at ic k O E C...Advanced Solar Inductive Charging Kinetic Harvesting Fuel Cells JP8 Fuel Cells Aerial ResupplyBATMAN Advanced Battery Technologies Conformal...90 lbs. of some from of energy during the mission  Ideally, this would be some expendable fuel , perhaps for fuel cells  Otherwise it creates

Implications of 'Peak Oil' for Atmospheric CO2 and Climate

NASA Astrophysics Data System (ADS)

Kharecha, P. A.; Hansen, J. E.

2008-12-01

Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming. The amounts of "proven" and potential fossil fuel reserves are uncertain and debated. Regardless of the true values, society has flexibility in the degree to which it chooses to exploit these reserves, especially unconventional fossil fuels and those located in extreme or pristine environments. If conventional oil production peaks within the next few decades, it may have a large effect on future atmospheric CO2 and climate change, depending upon subsequent energy choices. Assuming that proven oil and gas reserves do not greatly exceed estimates of the Energy Information Administration -- and recent trends are toward lower estimates -- we show that it is feasible to keep atmospheric CO2 from exceeding about 450 ppm by 2100, provided that emissions from coal, unconventional fossil fuels, and land use are constrained. Coal-fired facilities without sequestration must be phased out before midcentury to achieve this CO2 limit. It is also important to "stretch" conventional oil reserves via energy conservation and efficiency, thus averting strong pressures to extract liquid fuels from coal or unconventional fossil fuels while clean technologies are being developed for the era "beyond fossil fuels". We argue that a rising price on carbon emissions is needed to discourage conversion of the vast fossil resources into usable reserves, and to keep CO2 below 450 ppm. It is also plausible that CO2 can be returned below 350 ppm by 2100 or sooner, if more aggressive mitigation measures are enacted, most notably a phase-out of global coal emissions by circa 2030 and large- scale reforestation, primarily in the tropics but also in temperate regions.

Chapter 10: Research and Deployment of Renewable Bioenergy Production from Microalgae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Laurens, Lieve M; Glasser, Melodie

Recent progress towards the implementation of renewable bioenergy production has included microalgae, which have potential to significantly contribute to a viable future bioeconomy. In a current challenging energy landscape, where an increased demand for renewable fuels is projected and accompanied by plummeting fossil fuels' prices, economical production of algae-based fuels becomes more challenging. However, in the context of mitigating carbon emissions with the potential of algae to assimilate large quantities of CO2, there is a route to drive carbon sequestration and utilization to support a sustainable and secure global energy future. This chapter places international energy policy in the contextmore » of the current and projected energy landscape. The contribution that algae can make, is summarized as both a conceptual contribution as well as an overview of the commercial infrastructure installed globally. Some of the major recent developments and crucial technology innovations are the results of global government support for the development of algae-based bioenergy, biofuels and bioproduct applications, which have been awarded as public private partnerships and are summarized in this chapter.« less

Microfluidic microbial fuel cells: from membrane to membrane free

NASA Astrophysics Data System (ADS)

Yang, Yang; Ye, Dingding; Li, Jun; Zhu, Xun; Liao, Qiang; Zhang, Biao

2016-08-01

Microfluidic microbial fuel cells (MMFCs) are small carbon-neutral devices that use self-organized bacteria to degrade organic substrates and harness energy from the waste water. Conventional MMFCs have made great strides in the past decade and have overcome some limitations, such as high capital costs and low energy output. A co-laminar flow MFC has been first proposed in 2011 with the potential to be an attractively power source to niche applications. Co-laminar MFCs typically operate without any physical membranes separating the reactants, and bacterial ecosystems can be easily manipulated by regulating the inlet conditions. This paper highlights recent accomplishments in the development of co-laminar MFCs, emphasizing basic principles, mass transport and fluid dynamics including boundary layer theory, entrance conditions and mixing zone issues. Furthermore, the development of current techniques, major challenges and the potential research directions are discussed.

Background qualitative analysis of the European Reference Life Cycle Database (ELCD) energy datasets - part I: fuel datasets.

PubMed

Garraín, Daniel; Fazio, Simone; de la Rúa, Cristina; Recchioni, Marco; Lechón, Yolanda; Mathieux, Fabrice

2015-01-01

The aim of this study is to identify areas of potential improvement of the European Reference Life Cycle Database (ELCD) fuel datasets. The revision is based on the data quality indicators described by the ILCD Handbook, applied on sectorial basis. These indicators evaluate the technological, geographical and time-related representativeness of the dataset and the appropriateness in terms of completeness, precision and methodology. Results show that ELCD fuel datasets have a very good quality in general terms, nevertheless some findings and recommendations in order to improve the quality of Life-Cycle Inventories have been derived. Moreover, these results ensure the quality of the fuel-related datasets to any LCA practitioner, and provide insights related to the limitations and assumptions underlying in the datasets modelling. Giving this information, the LCA practitioner will be able to decide whether the use of the ELCD fuel datasets is appropriate based on the goal and scope of the analysis to be conducted. The methodological approach would be also useful for dataset developers and reviewers, in order to improve the overall DQR of databases.

Indoor air pollution and the lung in low- and medium-income countries.

PubMed

Kurmi, Om P; Lam, Kin Bong Hubert; Ayres, Jon G

2012-07-01

Over half the world's population, mostly from developing countries, use solid fuel for domestic purposes and are exposed to very high concentrations of harmful air pollutants with potential health effects such as respiratory problems, cardiovascular problems, infant mortality and ocular problems. The evidence also suggests that, although the total percentage of people using solid fuel is decreasing, the absolute number is currently increasing. Exposure to smoke from solid fuel burning increases the risk of chronic obstructive pulmonary disease (COPD) and lung cancer in adults, and acute lower respiratory tract infection/pneumonia in children. Despite the heterogeneity among studies, the association between COPD and exposure to smoke produced by burning different types of solid fuel is consistent. However, there is strong evidence that while coal burning is a risk factor for lung cancer, exposure to other biomass fuel smoke is less so. There is some evidence that reduction of smoke exposure using improved cooking stoves reduces the risk of COPD and, possibly, acute lower respiratory infection in children, so approaches to reduce biomass smoke exposure are likely to result in reductions in the global burden of respiratory disease.

Design of fuel cell powered data centers for sufficient reliability and availability

NASA Astrophysics Data System (ADS)

Ritchie, Alexa J.; Brouwer, Jacob

2018-04-01

It is challenging to design a sufficiently reliable fuel cell electrical system for use in data centers, which require 99.9999% uptime. Such a system could lower emissions and increase data center efficiency, but the reliability and availability of such a system must be analyzed and understood. Currently, extensive backup equipment is used to ensure electricity availability. The proposed design alternative uses multiple fuel cell systems each supporting a small number of servers to eliminate backup power equipment provided the fuel cell design has sufficient reliability and availability. Potential system designs are explored for the entire data center and for individual fuel cells. Reliability block diagram analysis of the fuel cell systems was accomplished to understand the reliability of the systems without repair or redundant technologies. From this analysis, it was apparent that redundant components would be necessary. A program was written in MATLAB to show that the desired system reliability could be achieved by a combination of parallel components, regardless of the number of additional components needed. Having shown that the desired reliability was achievable through some combination of components, a dynamic programming analysis was undertaken to assess the ideal allocation of parallel components.

Consumer Convenience and the Availability of Retail Stations as a Market Barrier for Alternative Fuel Vehicles: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melaina, M.; Bremson, J.; Solo, K.

2013-01-01

The availability of retail stations can be a significant barrier to the adoption of alternative fuel light-duty vehicles in household markets. This is especially the case during early market growth when retail stations are likely to be sparse and when vehicles are dedicated in the sense that they can only be fuelled with a new alternative fuel. For some bi-fuel vehicles, which can also fuel with conventional gasoline or diesel, limited availability will not necessarily limit vehicle sales but can limit fuel use. The impact of limited availability on vehicle purchase decisions is largely a function of geographic coverage andmore » consumer perception. In this paper we review previous attempts to quantify the value of availability and present results from two studies that rely upon distinct methodologies. The first study relies upon stated preference data from a discrete choice survey and the second relies upon a station clustering algorithm and a rational actor value of time framework. Results from the two studies provide an estimate of the discrepancy between stated preference cost penalties and a lower bound on potential revealed cost penalties.« less

Biofuel: an alternative to fossil fuel for alleviating world energy and economic crises.

PubMed

Bhattarai, Keshav; Stalick, Wayne M; McKay, Scott; Geme, Gija; Bhattarai, Nimisha

2011-01-01

The time has come when it is desirable to look for alternative energy resources to confront the global energy crisis. Consideration of the increasing environmental problems and the possible crisis of fossil fuel availability at record high prices dictate that some changes will need to occur sooner rather than later. The recent oil spill in the Gulf of Mexico is just another example of the environmental threats that fossil fuels pose. This paper is an attempt to explore various bio-resources such as corn, barley, oat, rice, wheat, sorghum, sugar, safflower, and coniferous and non-coniferous species for the production of biofuels (ethanol and biodiesel). In order to assess the potential production of biofuel, in this paper, countries are organized into three groups based on: (a) geographic areas; (b) economic development; and(c) lending types, as classified by the World Bank. First, the total fossil fuel energy consumption and supply and possible carbon emission from burning fossil fuel is projected for these three groups of countries. Second, the possibility of production of biofuel from grains and vegetative product is projected. Third, a comparison of fossil fuel and biofuel is done to examine energy sustainability issues.

Fuels planning: science synthesis and integration; social issues fact sheet 11: Challenges to collaboration

Treesearch

Christine Esposito

2006-01-01

Bringing the right people into a collaborative process can be difficult. Potential collaborators must all feel they have something to gain to justify investing resources, sharing knowledge, and perhaps compromising on goals and actions. This fact sheet discusses some of the common challenges that individuals, communities, and institutions face in collaboration.

Metabolites from inhalation of aerosolized S-8 synthetic jet fuel in rats.

PubMed

Tremblay, Raphael T; Martin, Sheppard A; Fisher, Jeffrey W

2011-01-01

Alternative fuels are being considered for civilian and military uses. One of these is S-8, a replacement jet fuel synthesized using the Fischer-Tropsch process, which contains no aromatic compounds and is mainly composed of straight and branched alkanes. Metabolites of S-8 fuel in laboratory animals have not been identified. The goal of this study was to identify metabolic products from exposure to aerosolized S-8 and a designed straight-chain alkane/polyaromatic mixture (decane, undecane, dodecane, tridecane, tetradecane, pentadecane, naphthalene, and 2-methylnaphthalene) in male Fischer 344 rats. Collected blood and tissue samples were analyzed for 70 straight and branched alcohols and ketones ranging from 7 to 15 carbons. No fuel metabolites were observed in the blood, lungs, brain, and fat following S-8 exposure. Metabolites were detected in the liver, urine, and feces. Most of the metabolites were 2- and 3-position alcohols and ketones of prominent hydrocarbons with very few 1- or 4-position metabolites. Following exposure to the alkane mixture, metabolites were observed in the blood, liver, and lungs. Interestingly, heavy metabolites (3-tridecanone, 2-tridecanol, and 2-tetradecanol) were observed only in the lung tissues possibly indicating that metabolism occurred in the lungs. With the exception of these heavy metabolites, the metabolic profiles observed in this study are consistent with previous studies reporting on the metabolism of individual alkanes. Further work is needed to determine the potential metabolic interactions of parent, primary, and secondary metabolites and identify more polar metabolites. Some metabolites may have potential use as biomarkers of exposure to fuels.

Do foreign direct investment and renewable energy consumption affect the CO2 emissions? New evidence from a panel ARDL approach to Kyoto Annex countries.

PubMed

Mert, Mehmet; Bölük, Gülden

2016-11-01

This study examines the impact of foreign direct investment (FDI) and the potential of renewable energy consumption on carbon dioxide (CO 2 ) emissions in 21 Kyoto countries using an unbalanced panel data. For this purpose, Environmental Kuznets Curve (EKC) hypothesis was tested using panel cointegration analysis. Panel causality tests show that there are significant long-run causalities from the variables to carbon emissions, renewable energy consumption, fossil fuel energy consumption and inflow foreign direct investments. The results of our model support the pollution haloes hypothesis which states that FDI brings in clean technology and improves the environmental standards. However, an inverted U-shaped relationship (EKC) was not supported by the estimated model for the 21 Kyoto countries. This means that economic growth cannot ensure environmental protection itself or environmental goals cannot await economic growth. Another important finding is that renewable energy consumption decreases carbon emissions. Based on the empirical results, some important policy implications emerge. Kyoto countries should stimulate the FDI inflows and usage of renewable energy consumption to mitigate the air pollution and meet the emission targets. This paper provides new insights into environment and energy policies through FDI inclusion.

Estimating the value of electricity storage in PJM: Arbitrage and some welfare effects

DOE PAGES

Sioshansi, Ramteen; Denholm, Paul; Jenkin, Thomas; ...

2008-10-31

Here, significant increases in prices and price volatility of natural gas and electricity have raised interest in the potential economic opportunities for electricity storage. In this paper, we analyze the arbitrage value of a price-taking storage device in PJM during the six-year period from 2002 to 2007, to understand the impact of fuel prices, transmission constraints, efficiency, storage capacity, and fuel mix. The impact of load-shifting for larger amounts of storage, where reductions in arbitrage are offset by shifts in consumer and producer surplus as well as increases in social welfare from a variety of sources, is also considered.

Great (Flame) Balls of Fire! Structure of Flame Balls at Low Lewis-number-2 (SOFBALL-2)

NASA Technical Reports Server (NTRS)

Ronney, Paul; Weiland, Karen J.; Over, Ann (Technical Monitor)

2002-01-01

Everyone knows that an automobile engine wastes fuel and energy when it runs with a fuel-rich mixture. 'Lean' burning, mixing in more air and less fuel, is better for the environment. But lean mixtures also lead to engine misfiring and rough operation. No one knows the ultimate limits for lean operation, for 'weak' combustion that is friendly to the environment while still moving us around. This is where the accidental verification of a decades-old prediction may have strong implications for designing and running low-emissions engines in the 21st century. In 1944, Soviet physicist Yakov Zeldovich predicted that stationary, spherical flames are possible under limited conditions in lean fuel-air mixtures. Dr. Paul Ronney of the University of Southern California accidentally discovered such 'flame balls' in experiments with lean hydrogen-air mixtures in 1984 during drop-tower experiments that provided just 2.2 seconds of near weightlessness. Experiments aboard NASA's low-g aircraft confirmed the results, but a thorough investigation was hampered by the aircraft's bumpy ride. And stable flame balls can only exist in microgravity. The potential for investigating combustion at the limits of flammability, and the implications for spacecraft fire safety, led to the Structure of Flame Balls at Low Lewis-number (SOFBALL) experiment flown twice aboard the Space Shuttle on the Microgravity Sciences Laboratory-1 (MSL-1) in 1997. Success there led to the planned reflight on STS-107. Flame balls are the weakest fires yet produced in space or on Earth. Typically each flame ball produced only 1 watt of thermal power. By comparison, a birthday candle produces 50 watts. The Lewis-number measures the rate of diffusion of fuel into the flame ball relative to the rate of diffusion of heat away from the flame ball. Lewis-number mixtures conduct heat poorly. Hydrogen and methane are the only fuels that provide low enough Lewis-numbers to produce stable flame balls, and even then only for very weak, barely flammable mixtures. Nevertheless, under these conditions flame balls give scientists the opportunity to test models in one of the simplest combustion experiments possible. SOFBALL-2 science objectives include: Improving our understanding of the flame ball phenomenon; Determining the conditions under which flame balls exist; Testing predictions of flame ball lifetimes; Acquiring more precise data for critical model comparison.

Modeling the effects of pelleting on the logistics of distillers grains shipping.

PubMed

Rosentrater, Kurt A; Kongar, Elif

2009-12-01

The energy security needs of energy importing nations continue to escalate. It is clear that biofuels can help meet some of the increasing need for energy. Theoretically, these can be produced from a variety of biological materials, including agricultural residues (such as corn stover and wheat straw), perennial grasses, legumes, algae, and other biological materials. Currently, however, the most heavily utilized material is corn starch. Industrial fuel ethanol production in the US primarily uses corn, because it is readily converted into fuel at a relatively low cost compared to other biomass sources. The production of corn-based ethanol in the US is dramatically increasing. As the industry continues to grow, the amount of byproducts and coproducts also increases. At the moment, the nonfermentable residues (which are dried and sold as distillers dried grains with solubles--DDGS) are utilized only as livestock feed. The sale of coproducts provides ethanol processors with a substantial revenue source and significantly increases the profitability of the production process. Even though these materials are used to feed animals in local markets, as the size and scope of the industry continues to grow, the need to ship large quantities of coproducts grows as well. This includes both domestic as well as international transportation. Value-added processing options offer the potential to increase the sustainability of each ethanol plant, and thus the industry overall. However, implementation of new technologies will be dependent upon how their costs interact with current processing costs and the logistics of coproduct deliveries. The objective of this study was to examine some of these issues by developing a computer model to determine potential cost ramifications of using various alternative technologies during ethanol processing. This paper focuses specifically on adding a densification unit operation (i.e., pelleting) to produce value-added DDGS at a fuel ethanol manufacturing plant. We have examined the economic implications of pelleting DDGS for varying DDGS production rates (100-1000 tons/d) and pelleting rates (0-100%), for a series of DDGS sales prices ($50-$200/ton). As the proportion of pelleting increases, the cost of transporting DDGS to distant markets drastically declines, because the rail cars can be filled to capacity. For example, at a DDGS sales price of $50/ton, 100% pelleting will reduce shipping costs (both direct and indirect) by 89% compared to shipping the DDGS in bulk form (i.e., no pelleting), whereas at a DDGS sales price of $200/ton, it will reduce costs by over 96%. It is clear that the sustainability of the ethanol industry can be improved by implementing pelleting technology for the coproducts, especially at those plants that ship their DDGS via rail.

Polymer electrolyte fuel cells

NASA Astrophysics Data System (ADS)

Gottesfeld, S.

The recent increase in attention to polymer electrolyte fuel cells (PEFC's) is the result of significant technical advances in this technology and the initiation of some projects for the demonstration of complete PEFC-based power system in a bus or in a passenger car. A PEFC powered vehicle has the potential for zero emission, high energy conversion efficiency and extended range compared to present day battery powered EV's. This paper describes recent achievements in R&D on PEFC's. The major thrust areas have been: (1) demonstration of membrane/electrode assemblies with stable high performance in life tests lasting 4000 hours, employing ultra-low Pt loadings corresponding to only 1/2 oz of Pt for the complete power source of a passenger car; (2) effective remedies for the high sensitivity of the Pt electrocatalyst to impurities in the fuel feed stream; and (3) comprehensive evaluation of the physicochemical properties of membrane and electrodes in the PEFC, clarifying the water management issues and enabling effective codes and diagnostics for this fuel cell.

Removal or storage of environmental pollutants and alternative fuel sources with inorganic adsorbents via host–guest encapsulation

DOE PAGES

Cramer, Alisha J.; Cole, Jacqueline M.

2017-05-08

The ever-increasing demands of the modern world continue to place substantial strain on the environment. To help alleviate the damage done to the natural world, the encapsulation of small molecules or ions (guests) into porous inorganic structural frameworks (hosts) provides a potential remedy for some of the environmental concerns facing us today. These concerns include the removal of harmful pollutants from water or air, the safe entrapment of nuclear waste materials, or the purification and storage of small molecules that act as alternative fuel sources. For this study, we review the trends in using inorganic materials as hostmedia for themore » removal or storage of various wastes and alternative fuels. In conclusion, we cover the treatment of water contaminated with dyes or heavy metals, air pollution alleviation via CO 2, SO x, NO x, and volatile organic compound containment, nuclear waste immobilization, and storage for H 2 and methane as alternative fuels.« less

The Science of Photons to Fuel

NASA Astrophysics Data System (ADS)

Chu, Steven

2008-09-01

Transportation consumes 28% of US energy, and 60% of that is consumed by personal transportation. Because liquid fuels have high energy density, they will be the dominant fuel, until batteries have improved enough to support plug-in cars on an economic basis. Fifty million acres of energy crops plus agricultural wastes can produce roughly half of all of current US consumption of gasoline. Although ethanol from corn has received much attention as a possible substitute for gasoline, other biofuels feedstocks such as perennial grasses and agricultural wastes have greater potential for a much more environmentally friendly substitute for oil. The advantages of grasses over food crops such as corn include higher yield for given water and nutrient inputs; lower soil depletion and fertilizer run-off pollution. The major challenge in biofuels production from perennials is to improve the efficiency of conversion of the plant material to fuel. This paper describes some of the research that is being done to make biofuels from cellulose.

Hypoxia and Redox Signaling on Extracellular Matrix Remodeling: From Mechanisms to Pathological Implications.

PubMed

Labrousse-Arias, David; Martínez-Ruiz, Antonio; Calzada, María J

2017-10-20

The extracellular matrix (ECM) is an essential modulator of cell behavior that influences tissue organization. It has a strong relevance in homeostasis and translational implications for human disease. In addition to ECM structural proteins, matricellular proteins are important regulators of the ECM that are involved in a myriad of different pathologies. Recent Advances: Biochemical studies, animal models, and study of human diseases have contributed to the knowledge of molecular mechanisms involved in remodeling of the ECM, both in homeostasis and disease. Some of them might help in the development of new therapeutic strategies. This review aims to review what is known about some of the most studied matricellular proteins and their regulation by hypoxia and redox signaling, as well as the pathological implications of such regulation. Matricellular proteins have complex regulatory functions and are modulated by hypoxia and redox signaling through diverse mechanisms, in some cases with controversial effects that can be cell or tissue specific and context dependent. Therefore, a better understanding of these regulatory processes would be of great benefit and will open new avenues of considerable therapeutic potential. Characterizing the specific molecular mechanisms that modulate matricellular proteins in pathological processes that involve hypoxia and redox signaling warrants additional consideration to harness the potential therapeutic value of these regulatory proteins. Antioxid. Redox Signal. 27, 802-822.

Invited Review: A review of deterministic effects in cyclic variability of internal combustion engines

DOE PAGES

Finney, Charles E.; Kaul, Brian C.; Daw, C. Stuart; ...

2015-02-18

Here we review developments in the understanding of cycle to cycle variability in internal combustion engines, with a focus on spark-ignited and premixed combustion conditions. Much of the research on cyclic variability has focused on stochastic aspects, that is, features that can be modeled as inherently random with no short term predictability. In some cases, models of this type appear to work very well at describing experimental observations, but the lack of predictability limits control options. Also, even when the statistical properties of the stochastic variations are known, it can be very difficult to discern their underlying physical causes andmore » thus mitigate them. Some recent studies have demonstrated that under some conditions, cyclic combustion variations can have a relatively high degree of low dimensional deterministic structure, which implies some degree of predictability and potential for real time control. These deterministic effects are typically more pronounced near critical stability limits (e.g. near tipping points associated with ignition or flame propagation) such during highly dilute fueling or near the onset of homogeneous charge compression ignition. We review recent progress in experimental and analytical characterization of cyclic variability where low dimensional, deterministic effects have been observed. We describe some theories about the sources of these dynamical features and discuss prospects for interactive control and improved engine designs. In conclusion, taken as a whole, the research summarized here implies that the deterministic component of cyclic variability will become a pivotal issue (and potential opportunity) as engine manufacturers strive to meet aggressive emissions and fuel economy regulations in the coming decades.« less

Implications of electric vehicle penetration on federal and state highway revenues.

DOT National Transportation Integrated Search

2017-02-01

This report summarizes the results of research conducted to determine if current and : near future electric vehicle (EV) sales will have an impact on motor fuel tax revenues as : part of the Federal Highway Trust Fund (HTF). Gasoline and diesel fuel ...

Applying Thermodynamics to Fossil Fuels: Heats of Combustion from Elemental Compositions.

ERIC Educational Resources Information Center

Lloyd, William G.; Davenport, Derek A.

1980-01-01

Discussed are the calculations of heats of combustions of some selected fossil fuel compounds such as some foreign shale oils and United States coals. Heating values for coal- and petroleum-derived fuel oils are also presented. (HM)

Pore growth in U-Mo/Al dispersion fuel

NASA Astrophysics Data System (ADS)

Kim, Yeon Soo; Jeong, G. Y.; Sohn, D.-S.; Jamison, L. M.

2016-09-01

U-Mo/Al dispersion fuel is currently under development in the DOE's Material Management and Minimization program to convert HEU-fueled research reactors to LEU-fueled reactors. In some demanding conditions in high-power and high-performance reactors, large pores form in the interaction layers between the U-Mo fuel particles and the Al matrix, which pose a potential to cause fuel failure. In this study, comprehension of the formation and growth of these pores was explored. As a product, a model to predict pore growth and porosity increase was developed. The model includes three major topics: fission gas release from the U-Mo and the IL to the pores, stress evolution in the fuel meat, and the effect of amorphous IL growth. Well-characterized in-pile data from reduced-size plates were used to fit the model parameters. A data set from full-sized plates, independent and distinctively different from those used to fit the model parameters, was used to examine the accuracy of the model. The model showed fair agreement with the measured data. The model suggested that the growth of the IL has a critical effect on pore growth, as both its material properties and energetics are favorable to pore formation. Therefore, one area of the current effort, focused on suppressing IL growth, appears to be on the right track to improve the performance of this fuel.

Alternate-Fueled Flight: Halophytes, Algae, Bio-, and Synthetic Fuels

NASA Technical Reports Server (NTRS)

Hendricks, R. C.

2012-01-01

Synthetic and biomass fueling are now considered to be near-term aviation alternate fueling. The major impediment is a secure sustainable supply of these fuels at reasonable cost. However, biomass fueling raises major concerns related to uses of common food crops and grasses (some also called "weeds") for processing into aviation fuels. These issues are addressed, and then halophytes and algae are shown to be better suited as sources of aerospace fuels and transportation fueling in general. Some of the history related to alternate fuels use is provided as a guideline for current and planned alternate fuels testing (ground and flight) with emphasis on biofuel blends. It is also noted that lessons learned from terrestrial fueling are applicable to space missions. These materials represent an update (to 2009) and additions to the Workshop on Alternate Fueling Sustainable Supply and Halophyte Summit at Twinsburg, Ohio, October 17 to 18, 2007.

Alternate-Fueled Flight: Halophytes, Algae, Bio-, and Synthetic Fuels

NASA Technical Reports Server (NTRS)

Hendricks, R. C.

2007-01-01

Synthetic and biomass fueling are now considered to be near-term aviation alternate fueling. The major impediment is a secure sustainable supply of these fuels at reasonable cost. However, biomass fueling raises major concerns related to uses of common food crops and grasses (some also called "weeds") for processing into aviation fuels. These issues are addressed, and then halophytes and algae are shown to be better suited as sources of aerospace fuels and transportation fueling in general. Some of the history related to alternate fuels use is provided as a guideline for current and planned alternate fuels testing (ground and flight) with emphasis on biofuel blends. It is also noted that lessons learned from terrestrial fueling are applicable to space missions. These materials represent an update and additions to the Workshop on Alternate Fueling Sustainable Supply and Halophyte Summit at Twinsburg, OH, Oct. 17 to 18, 2007 (ref. 1).

Project Galaxy - Sustianable Resource Supply and Environmental Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Downing, Mark; Wimmer, Robert

2012-03-01

Understanding what it takes to move from a corn-based liquid fuels industry to one that is cellulosic-based requires a complex transition over time. This transition implies, among other things, a shift from annual cropping systems considered under United States Department of Agriculture (USDA) policy as commodity crops, to perennial lignocellulosic crops that are herbaceous and wood-based. Because of changes in land use as well as biomass and other crop supplies, land-based environmental amenities such as water quality, soil health and tilth, air quality, and animal and avian species populations and their diversity change also. Environmental effects are measured as magnitudesmore » (how much they are impacted), and direction of the impact (either positive or negative). By developing a series of quantitative and qualitative metrics, the larger issue of defining relative sustainability may be addressed, and this can be done at a finer detail of regional (scale) and environmental amenity-specific impacts. Although much literature exists about research relevant to specific environmental variables, there is no published, documented, nor research literature on direct application of environmental over-compliance with regards a 'biorefinery.' Our three goals were to (1) understand and quantify bioenergy sustainability and some key environmental effects in a generic set of examples; (2) explain the effort and means to define and quantify specific qualitative environmental measures, and to determine a way to understand changes in these measures over time and what their implications might be; and (3) use these outcomes to evaluate potential sites in any geographic area. This would permit assessment of candidate locations, combined with an understanding of co-production of fuels, chemicals, and electric power, to interpret sustainability measures and the relationship between environmental sustainability and economic sustainability. The process of determining environmental sustainability effects as a result of providing renewable energy is complex. We have only included in this report environmental effects as a result of producing biomass for the biorefinery, and the area represented by the footprint of the biorefinery itself. In doing this, we have defined critical environmental variables (water, soil, air, and flora and fauna) and discussed some measurable indicators used to quantify effects such as nitrate content, soil organic matter, air particulates, and avian species diversity, respectively. We also point out the need to perform specific sustainability risk assessments, and the need to continually evaluate the life cycle inventory with an accompanying life-cycle assessment. Only in this dynamic framework can environmental sustainability be determined, evaluated and assessed, and contrasted with economic sustainability goals of a firm or an industry.« less

National Policy Implications of Storing Nuclear Waste in the Pacific Region,

DTIC Science & Technology

1981-01-01

US Congress, Senate, Committee on Energy and Natural Resources, Pacific Spent Nuclear Fuel Storage , Hearing...selected. 17 One type of shipping cask which has been used to transport spent fuel assemblies to the Nevada Test Site is a leakproof steel cask that can...discussion the following conclusions on the nuclear waste storage issue appear valid. The Reagan decision to reprocess spent fuel has not changed US

An Overview of Electron Acceptors in Microbial Fuel Cells

PubMed Central

Ucar, Deniz; Zhang, Yifeng; Angelidaki, Irini

2017-01-01

Microbial fuel cells (MFC) have recently received increasing attention due to their promising potential in sustainable wastewater treatment and contaminant removal. In general, contaminants can be removed either as an electron donor via microbial catalyzed oxidization at the anode or removed at the cathode as electron acceptors through reduction. Some contaminants can also function as electron mediators at the anode or cathode. While previous studies have done a thorough assessment of electron donors, cathodic electron acceptors and mediators have not been as well described. Oxygen is widely used as an electron acceptor due to its high oxidation potential and ready availability. Recent studies, however, have begun to assess the use of different electron acceptors because of the (1) diversity of redox potential, (2) needs of alternative and more efficient cathode reaction, and (3) expanding of MFC based technologies in different areas. The aim of this review was to evaluate the performance and applicability of various electron acceptors and mediators used in MFCs. This review also evaluated the corresponding performance, advantages and disadvantages, and future potential applications of select electron acceptors (e.g., nitrate, iron, copper, perchlorate) and mediators. PMID:28469607

Issues of Commonality. Volume II. Issue Analysis.

DTIC Science & Technology

1980-12-01

lubricating oil, and residual oil. 68 ° B Diesel fuel and kerosene make up what are known as the middle distillates. Jet fuels are blends from this...group of distillates which include some gasoline and some heavier oils. The range of hydrocarbons selected for this blending determines the "cut" of...the fuel. Wide-cut fuels are blended fram a wide range of hydrocarbons; narrow-cut fuels include only a small range of hydrocarbons from the

Electrocatalyst for alcohol oxidation at fuel cell anodes

DOEpatents

Adzic, Radoslav [East Setauket, NY; Kowal, Andrzej [Cracow, PL

2011-11-02

In some embodiments a ternary electrocatalyst is provided. The electrocatalyst can be used in an anode for oxidizing alcohol in a fuel cell. In some embodiments, the ternary electrocatalyst may include a noble metal particle having a surface decorated with clusters of SnO.sub.2 and Rh. The noble metal particles may include platinum, palladium, ruthenium, iridium, gold, and combinations thereof. In some embodiments, the ternary electrocatalyst includes SnO.sub.2 particles having a surface decorated with clusters of a noble metal and Rh. Some ternary electrocatalysts include noble metal particles with clusters of SnO.sub.2 and Rh at their surfaces. In some embodiments the electrocatalyst particle cores are nanoparticles. Some embodiments of the invention provide a fuel cell including an anode incorporating the ternary electrocatalyst. In some aspects a method of using ternary electrocatalysts of Pt, Rh, and SnO.sub.2 to oxidize an alcohol in a fuel cell is described.

[Research on carbon reduction potential of electric vehicles for low-carbon transportation and its influencing factors].

PubMed

Shi, Xiao-Qing; Li, Xiao-Nuo; Yang, Jian-Xin

2013-01-01

Transportation is the key industry of urban energy consumption and carbon emissions. The transformation of conventional gasoline vehicles to new energy vehicles is an important initiative to realize the goal of developing low-carbon city through energy saving and emissions reduction, while electric vehicles (EV) will play an important role in this transition due to their advantage in energy saving and lower carbon emissions. After reviewing the existing researches on energy saving and emissions reduction of electric vehicles, this paper analyzed the factors affecting carbon emissions reduction. Combining with electric vehicles promotion program in Beijing, the paper analyzed carbon emissions and reduction potential of electric vehicles in six scenarios using the optimized energy consumption related carbon emissions model from the perspective of fuel life cycle. The scenarios included power energy structure, fuel type (energy consumption per 100 km), car type (CO2 emission factor of fuel), urban traffic conditions (speed), coal-power technologies and battery type (weight, energy efficiency). The results showed that the optimized model was able to estimate carbon emissions caused by fuel consumption more reasonably; electric vehicles had an obvious restrictive carbon reduction potential with the fluctuation of 57%-81.2% in the analysis of six influencing factors, while power energy structure and coal-power technologies play decisive roles in life-cycle carbon emissions of electric vehicles with the reduction potential of 78.1% and 81.2%, respectively. Finally, some optimized measures were proposed to reduce transport energy consumption and carbon emissions during electric vehicles promotion including improving energy structure and coal technology, popularizing energy saving technologies and electric vehicles, accelerating the battery R&D and so on. The research provides scientific basis and methods for the policy development for the transition of new energy vehicles in low-carbon transport.

Lubricity of well-characterized jet and broad-cut fuels by ball-on-cylinder machine

NASA Technical Reports Server (NTRS)

Prok, G. M.; Kim, W. S.

1984-01-01

A ball-on-cylinder machine (BOCM) was used to measure the lubricity of fuels. The fuels tested were well-characterized fuels available from other programs at the NASA Lewis Research Center plus some in-house mildly hydroprocessed shale fuels from other programs included Jet-A, ERBS fuel, ERBS blends, and blend stock. The BOCM tests were made before and after clay treatment of some of these fuels with both humidified air and dry nitrogen as the preconditioning and cover gas. As expected, clay treatment always reduced fuel lubricity. Using nitrogen preconditioning and cover gas always resulted in a smaller wear scar diameter than when humidified air was used. Also observed was an indication of lower lubricity with lower boiling range fuels and lower aromatic fuels. Gas chromatographic analysis indicted changes in BOCM-stressed fuels.

Implications of Fuel-Efficient Vehicles on Ride Quality and Passenger Acceptance : Workshop Proceedings, Woods Hole, Massachusetts, September 6-8, 1978

DOT National Transportation Integrated Search

1979-08-01

Four workshops were conducted under the auspices of the Transportation Research Board. The topics of discussion included ride quality and passenger acceptance problems associated with enhanced fuel efficiency of automobiles (Group A) and aircraft (Gr...

Tronto's Notion of "Privileged Irresponsibility" and the Reconceptualisation of Care: Implications for Critical Pedagogies of Emotion in Higher Education

ERIC Educational Resources Information Center

Zembylas, Michalinos; Bozalek, Vivienne; Shefer, Tammy

2014-01-01

This article takes on some of care theorist Joan Tronto's ideas on care and responsibility and asks what implications they have for critical pedagogies in higher education. The authors argue that Tronto's political ethics of care framework enriches the transformative potential of critical pedagogies, because it helps expose how power and…

Implications of sustainability for the United States light-duty transportation sector

DOE PAGES

Gearhart, Chris

2016-08-08

This article reviews existing literature to assess the consensus of the scientific and engineering communities concerning the potential for the United States’ light-duty transportation sector to meet a goal of 80% reduction in vehicle emissions and examine what it will take to meet this target. Climate change is a problem that must be solved. The primary cause of this problem is burning of fossil fuels to generate energy. A dramatic reduction in carbon emissions must happen soon, and a significant fraction of this reduction must come from the transportation sector. This paper reviews existing literature to assess the consensus ofmore » the scientific and engineering communities concerning the potential for the United States' light-duty transportation sector to meet a goal of 80% reduction in vehicle emissions and examine what it will take to meet this target. It is unlikely that reducing energy consumption in just vehicles with gasoline-based internal combustion drivetrains will be sufficient to meet GHG emission-reduction targets. This paper explores what additional benefits are possible through the adoption of alternative energy sources, looking at three possible on-vehicle energy carriers: carbon-based fuels, hydrogen, and batteries.« less

A Model of Carbon Capture and Storage with Demonstration of Global Warming Potential and Fossil Fuel Resource Use Efficiency

NASA Astrophysics Data System (ADS)

Suebsiri, Jitsopa

Increasing greenhouse gas concentration in the atmosphere influences global climate change even though the level of impact is still unclear. Carbon dioxide capture and storage (CCS) is increasingly seen as an important component of broadly based greenhouse gas reduction measures. Although the other greenhouse gases are more potent, the sheer volume of CO 2 makes it dominant in term of its effect in the atmosphere. To understand the implications, CCS activities should be studied from a full life cycle perspective. This thesis outlines the successful achievement of the objectives of this study in conducting life cycle assessment (LCA), reviewing the carbon dioxide implications only, combining two energy systems, coal-fired electrical generations and CO2 used for enhanced oil recovery (EOR). LCA is the primary approach used in this study to create a tool for CCS environmental evaluation. The Boundary Dam Power Station (BDPS) and the Weyburn-Midale CO 2 EOR Project in Saskatchewan, Canada, are studied and adopted as case scenarios to find the potential for effective application of CCS in both energy systems. This study demonstrates two levels of retrofitting of the BDPS, retrofit of unit 3 or retrofit of all units, combined with three options for CO 2 geological storage: deep saline aquifer, CO2 EOR, and a combination of deep saline aquifer storage and CO2 EOR. Energy output is considered the product of combining these two energy resources (coal and oil). Gigajoules (GJ) are used as the fundamental unit of measurement in comparing the combined energy types. The application of this tool effectively demonstrates the results of application of a CCS system concerning global warming potential (GWP) and fossil fuel resource use efficiency. Other environmental impacts could be analyzed with this tool as well. In addition, the results demonstrate that the GWP reduction is directly related to resource use efficiency. This means the lower the GWP of CCS, the lower resource use efficiency as well. Three processes, coal mining, power production including CO2 capture unit operation, and crude oil usage, must be included when the GWP of CCS is calculated. Moreover, the results from the sensitivity analysis of power generation efficiency present not only a significant reduction of GWP, but also a competitive solution for improving or at least preventing the decrease of fossil fuel resource use efficiency when CCS is applied.

Dissolved organic carbon in the precipitation of Seoul, Korea: Implications for global wet depositional flux of fossil-fuel derived organic carbon

NASA Astrophysics Data System (ADS)

Yan, Ge; Kim, Guebuem

2012-11-01

Precipitation was sampled in Seoul over a one-year period from 2009 to 2010 to investigate the sources and fluxes of atmospheric dissolved organic carbon (DOC). The concentrations of DOC varied from 15 μM to 780 μM, with a volume-weighted average of 94 μM. On the basis of correlation analysis using the commonly acknowledged tracers, such as vanadium, the combustion of fossil-fuels was recognized to be the dominant source. With the aid of air mass backward trajectory analyses, we concluded that the primary fraction of DOC in our precipitation samples originated locally in Korea, albeit the frequent long-range transport from eastern and northeastern China might contribute substantially. In light of the relatively invariant organic carbon to sulfur mass ratios in precipitation over Seoul and other urban regions around the world, the global magnitude of wet depositional DOC originating from fossil-fuels was calculated to be 36 ± 10 Tg C yr-1. Our study further underscores the potentially significant environmental impacts that might be brought about by this anthropogenically derived component of organic carbon in the atmosphere.

A Techno-Economic Analysis of Emission Controls on Hydrocarbon Biofuel Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhatt, Arpit; Zhang, Yimin; Davis, Ryan

Biofuels have the potential to reduce our dependency on petroleum-derived transportation fuels and decrease greenhouse gas (GHG) emissions. Although the overall GHG emissions from biofuels are expected to be lower when compared to those of petroleum fuels, the process of converting biomass feedstocks into biofuels emits various air pollutants, which may be subject to federal air quality regulation or emission limits. While prior research has evaluated the technical and economic feasibility of biofuel technologies, gaps still exist in understanding the regulatory issues associated with the biorefineries and their economic implications on biofuel production costs (referred to as minimum fuel sellingmore » price (MFSP) in this study). The aim of our research is to evaluate the economic impact of implementing emission reduction technologies at biorefineries and estimate the cost effectiveness of two primary control technologies that may be required for air permitting purposes. We analyze a lignocellulosic sugars-to-hydrocarbon biofuel production pathway developed by the National Renewable Energy Laboratory (NREL) and implement air emission controls in Aspen Plus to evaluate how they affect the MFSP. Results from this analysis can help inform decisions about biorefinery siting and sizing, as well as mitigate the risks associated with air permitting.« less

Human health impacts of biodiesel use in on-road heavy duty diesel vehicles in Canada.

PubMed

Rouleau, Mathieu; Egyed, Marika; Taylor, Brett; Chen, Jack; Samaali, Mehrez; Davignon, Didier; Morneau, Gilles

2013-11-19

Regulatory requirements for renewable content in diesel fuel have been adopted in Canada. Fatty acid alkyl esters, that is, biodiesel, will likely be used to meet the regulations. However, the impacts on ambient atmospheric pollutant concentrations and human health outcomes associated with the use of biodiesel fuel blends in heavy duty diesel vehicles across Canada have not been evaluated. The objective of this study was to assess the potential human health implications of the widespread use of biodiesel in Canada compared to those from ultralow sulfur diesel (ULSD). The health impacts/benefits resulting from biodiesel use were determined with the Air Quality Benefits Assessment Tool, based on output from the AURAMS air quality modeling system and the MOBILE6.2C on-road vehicle emissions model. Scenarios included runs for ULSD and biodiesel blends with 5 and 20% of biodiesel by volume, and compared their use in 2006 and 2020. Although modeling and data limitations exist, the results of this study suggested that the use of biodiesel fuel blends compared to ULSD was expected to result in very minimal changes in air quality and health benefits/costs across Canada, and these were likely to diminish over time.

Brassica carinata as an alternative oil crop for the production of biodiesel in Italy: engine performance and regulated and unregulated exhaust emissions.

PubMed

Cardone, Massimo; Prati, Maria Vittoria; Rocco, Vittorio; Seggiani, Maurizia; Senatore, Adolfo; Vitoloi, Sandra

2002-11-01

A comparison of the performance of Brassica carinata oil-derived biodiesel with a commercial rapeseed oil-derived biodiesel and petroleum diesel fuel is discussed as regards engine performance and regulated and unregulated exhaust emissions. B. carinata is an oil crop that can be cultivated in coastal areas of central-southern Italy, where it is more difficult to achieve the productivity potentials of Brassica napus (by far the most common rapeseed cultivated in continental Europe). Experimental tests were carried out on a turbocharged direct injection passenger car diesel engine fueled with 100% biodiesel. The unregulated exhaust emissions were characterized by determining the SOOT and soluble organic fraction content in the particulate matter, together with analysis of the content and speciation of polycyclic aromatic hydrocarbons, some of which are potentially carcinogenic, and of carbonyl compounds (aldehydes, ketones) that act as ozone precursors. B. carinata and commercial biodiesel behaved similarly as far as engine performance and regulated and unregulated emissions were concerned. When compared with petroleum diesel fuel, the engine test bench analysis did not show any appreciable variation of output engine torque values, while there was a significant difference in specific fuel consumption data at the lowest loads for the biofuels and petroleum diesel fuel. The biofuels were observed to produce higher levels of NOx concentrations and lower levels of PM with respect to the diesel fuel. The engine heat release analysis conducted shows that there is a potential for increased thermal NOx generation when firing biodiesel with no prior modification to the injection timing. It seems that, for both the biofuels, this behavior is caused by an advanced combustion evolution, which is particularly apparent at the higher loads. When compared with petroleum diesel fuel, biodiesel emissions contain less SOOT, and a greater fraction of the particulate was soluble. The analysis and speciation of the soluble organic fraction of biodiesel particulate suggest that the carcinogenic potential of the biodiesel emissions is probably lower than that of petroleum diesel. Its better adaptivity and productivity in clay and sandy-type soils and in semiarid temperate climate and the fact that the performance of its derived biodiesel is quite similar to commercial biodiesel make B. carinata a promising oil crop that could offer the possibility of exploiting the Mediterranean marginal areas for energetic purposes.

Thickness and Fuel Preheating Effects on Material Flammability in Microgravity from the BASS Experiment

NASA Technical Reports Server (NTRS)

Ferkul, Paul V.; Olson, Sandra L.; Takahashi, Fumiaki; Endo, Makoto; Johnson, Michael C.; T'ien, James S.

2013-01-01

The Burning and Suppression of Solids (BASS) experiment was performed on the International Space Station. Microgravity combustion tests burning thin and thick flat samples, acrylic spheres, and candles were conducted. The samples were mounted inside a small wind tunnel which could impose air flow speeds up to 40 cms. The wind tunnel was installed in the Microgravity Science Glovebox which supplied power, imaging, and a level of containment. The effects of air flow speed, fuel thickness, fuel preheating, and nitrogen dilution on flame appearance, flame growth, and spread rates were determined in both the opposed and concurrent flow configuration. In some cases, a jet of nitrogen was introduced to attempt to extinguish the flame. Microgravity flames were found to be especially sensitive to air flow speed in the range 0 to 5 cms. The gas phase response is much faster compared to the solid and so as the flow speed is changed, the flame responds with almost no delay. At the lowest speeds examined (less than 1 cms) all the flames tended to become dim blue and very stable. However, heat loss at these very low convective rates is small so the flames can burn for a long time. At moderate flow speeds (between about 1 and 5 cms) the flame continually heats the solid fuel resulting in an increasing fuel temperature, higher rate of fuel vaporization, and a stronger, more luminous flame as time progresses. Only the smallest flames burning acrylic slabs appeared to be adversely influenced by solid conductive heat loss, but even these burned for over 5 minutes before self-extinguishing. This has implications for spacecraft fire safety since a tiny flame might be undetected for a long time. While the small flame is not particularly hazardous if it remains small, the danger is that it might flare up if the air convection is suddenly increased or if the flame spreads into another fuel source.

Geography of Existing and Potential Alternative Fuel Markets in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, C.; Hettinger, D.

When deploying alternative fuels, it is paramount to match the right fuel with the right location, in accordance with local market conditions. We used six market indicators to evaluate the existing and potential regional market health for each of the five most commonly deployed alternative fuels: electricity (used by plug-in electric vehicles), biodiesel (blends of B20 and higher), E85 ethanol, compressed natural gas (CNG), and propane. Each market indicator was mapped, combined, and evaluated by industry experts. This process revealed the weight the market indicators should be given, with the proximity of fueling stations being the most important indicator, followedmore » by alternative fuel vehicle density, gasoline prices, state incentives, nearby resources, and finally, environmental benefit. Though markets vary among states, no state received 'weak' potential for all five fuels, indicating that all states have an opportunity to use at least one alternative fuel. California, Illinois, Indiana, Pennsylvania, and Washington appear to have the best potential markets for alternative fuels in general, with each sporting strong markets for four of the fuels. Wyoming showed the least potential, with weak markets for all alternative fuels except for CNG, for which it has a patchy market. Of all the fuels, CNG is promising in the greatest number of states--largely because freight traffic provides potential demand for many far-reaching corridor markets and because the sources of CNG are so widespread geographically.« less

Cell disruption for microalgae biorefineries.

PubMed

Günerken, E; D'Hondt, E; Eppink, M H M; Garcia-Gonzalez, L; Elst, K; Wijffels, R H

2015-01-01

Microalgae are a potential source for various valuable chemicals for commercial applications ranging from nutraceuticals to fuels. Objective in a biorefinery is to utilize biomass ingredients efficiently similarly to petroleum refineries in which oil is fractionated in fuels and a variety of products with higher value. Downstream processes in microalgae biorefineries consist of different steps whereof cell disruption is the most crucial part. To maintain the functionality of algae biochemicals during cell disruption while obtaining high disruption yields is an important challenge. Despite this need, studies on mild disruption of microalgae cells are limited. This review article focuses on the evaluation of conventional and emerging cell disruption technologies, and a comparison thereof with respect to their potential for the future microalgae biorefineries. The discussed techniques are bead milling, high pressure homogenization, high speed homogenization, ultrasonication, microwave treatment, pulsed electric field treatment, non-mechanical cell disruption and some emerging technologies. Copyright © 2015 Elsevier Inc. All rights reserved.

Air pollution and rural biomass fuels in developing countries: A pilot village study in India and implications for research and policy

NASA Astrophysics Data System (ADS)

Smith, Kirk R.; Aggarwal, A. L.; Dave ^✠, R. M.

The results of a pilot study in four Indian villages of personal exposure to total suspended particulates (TSP) and particulate benzo(a)pyrene (BaP) of women cooking on simple stoves using traditional biomass fuels are presented together with socioeconomic and fuel-use determinations. TSP exposures averaged nearly 7 mg m -3 and BaP about 4000 ng m -3 during the cooking period which occupied 10% of the year. The factors affecting indoor air pollution exposures in rural areas of developing countries are categorized and discussed by reference to the few published field measurements. Comparisons are made with other common exposures in urban and occupational settings. The sparse information indicates that rural exposures are relatively high. Subjects for future research are outlined and general policy implications mentioned.

Emissions Scenarios and Fossil-fuel Peaking

NASA Astrophysics Data System (ADS)

Brecha, R.

2008-12-01

Intergovernmental Panel on Climate Change (IPCC) emissions scenarios are based on detailed energy system models in which demographics, technology and economics are used to generate projections of future world energy consumption, and therefore, of greenhouse gas emissions. Built into the assumptions for these scenarios are estimates for ultimately recoverable resources of various fossil fuels. There is a growing chorus of critics who believe that the true extent of recoverable fossil resources is much smaller than the amounts taken as a baseline for the IPCC scenarios. In a climate optimist camp are those who contend that "peak oil" will lead to a switch to renewable energy sources, while others point out that high prices for oil caused by supply limitations could very well lead to a transition to liquid fuels that actually increase total carbon emissions. We examine a third scenario in which high energy prices, which are correlated with increasing infrastructure, exploration and development costs, conspire to limit the potential for making a switch to coal or natural gas for liquid fuels. In addition, the same increasing costs limit the potential for expansion of tar sand and shale oil recovery. In our qualitative model of the energy system, backed by data from short- and medium-term trends, we have a useful way to gain a sense of potential carbon emission bounds. A bound for 21st century emissions is investigated based on two assumptions: first, that extractable fossil-fuel resources follow the trends assumed by "peak oil" adherents, and second, that little is done in the way of climate mitigation policies. If resources, and perhaps more importantly, extraction rates, of fossil fuels are limited compared to assumptions in the emissions scenarios, a situation can arise in which emissions are supply-driven. However, we show that even in this "peak fossil-fuel" limit, carbon emissions are high enough to surpass 550 ppm or 2°C climate protection guardrails. Some indicators are presented that the scenario presented here should not be disregarded, and comparisons are made to the outputs of emission scenarios used for the IPCC reports.

Impact of policy on greenhouse gas emissions and economics of biodiesel production.

PubMed

Olivetti, Elsa; Gülşen, Ece; Malça, João; Castanheira, Erica; Freire, Fausto; Dias, Luis; Kirchain, Randolph

2014-07-01

As an alternative transportation fuel to petrodiesel, biodiesel has been promoted within national energy portfolio targets across the world. Early estimations of low lifecycle greenhouse gas (GHG) emissions of biodiesel were a driver behind extensive government support in the form of financial incentives for the industry. However, studies consistently report a high degree of uncertainty in these emissions estimates, raising questions concerning the carbon benefits of biodiesel. Furthermore, the implications of feedstock blending on GHG emissions uncertainty have not been explicitly addressed despite broad practice by the industry to meet fuel quality standards and to control costs. This work investigated the impact of feedstock blending on the characteristics of biodiesel by using a chance-constrained (CC) blend optimization method. The objective of the optimization is minimization of feedstock costs subject to fuel standards and emissions constraints. Results indicate that blending can be used to manage GHG emissions uncertainty characteristics of biodiesel, and to achieve cost reductions through feedstock diversification. Simulations suggest that emissions control policies that restrict the use of certain feedstocks based on their GHG estimates overlook blending practices and benefits, increasing the cost of biodiesel. In contrast, emissions control policies which recognize the multifeedstock nature of biodiesel provide producers with feedstock selection flexibility, enabling them to manage their blend portfolios cost effectively, potentially without compromising fuel quality or emissions reductions.

Policy Determination on Limiting Potential to Emit for Koch Refining Company's Clean Fuels Project

EPA Pesticide Factsheets

This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

Waste Estimates for a Future Recycling Plant in the US Based Upon AREVA Operating Experience - 13206

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foare, Genevieve; Meze, Florian; Bader, Sven

2013-07-01

Estimates of process and secondary wastes produced by a recycling plant built in the U.S., which is composed of a used nuclear fuel (UNF) reprocessing facility and a mixed oxide (MOX) fuel fabrication facility, are performed as part of a U.S. Department of Energy (DOE) sponsored study [1]. In this study, a set of common inputs, assumptions, and constraints were identified to allow for comparison of these wastes between different industrial teams. AREVA produced a model of a reprocessing facility, an associated fuel fabrication facility, and waste treatment facilities to develop the results for this study. These facilities were dividedmore » into a number of discrete functional areas for which inlet and outlet flow streams were clearly identified to allow for an accurate determination of the radionuclide balance throughout the facility and the waste streams. AREVA relied primarily on its decades of experience and feedback from its La Hague (reprocessing) and MELOX (MOX fuel fabrication) commercial operating facilities in France to support this assessment. However, to perform these estimates for a U.S. facility with different regulatory requirements and to take advantage of some technological advancements, such as in the potential treatment of off-gases, some deviations from this experience were necessary. A summary of AREVA's approach and results for the recycling of 800 metric tonnes of initial heavy metal (MTIHM) of LWR UNF per year into MOX fuel under the assumptions and constraints identified for this DOE study are presented. (authors)« less

Effect of indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women.

PubMed

Agrawal, S; Yamamoto, S

2015-06-01

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005-2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39,657 women aged 15-49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26-3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings. © 2014 The Authors. Indoor Air published by John Wiley & Sons Ltd.

Effect of Indoor air pollution from biomass and solid fuel combustion on symptoms of preeclampsia/eclampsia in Indian women

PubMed Central

Agrawal, S; Yamamoto, S

2015-01-01

Available evidence concerning the association between indoor air pollution (IAP) from biomass and solid fuel combustion and preeclampsia/eclampsia is not available in developing countries. We investigated the association between exposure to IAP from biomass and solid fuel combustion and symptoms of preeclampsia/eclampsia in Indian women by analyzing cross-sectional data from India's third National Family Health Survey (NFHS-3, 2005–2006). Self-reported symptoms of preeclampsia/eclampsia during pregnancy such as convulsions (not from fever), swelling of legs, body or face, excessive fatigue or vision difficulty during daylight, were obtained from 39 657 women aged 15–49 years who had a live birth in the previous 5 years. Effects of exposure to cooking smoke, ascertained by type of fuel used for cooking on preeclampsia/eclampsia risk, were estimated using logistic regression after adjusting for various confounders. Results indicate that women living in households using biomass and solid fuels have two times higher likelihood of reporting preeclampsia/eclampsia symptoms than do those living in households using cleaner fuels (OR = 2.21; 95%: 1.26–3.87; P = 0.006), even after controlling for the effects of a number of potentially confounding factors. This study is the first to empirically estimate the associations of IAP from biomass and solid fuel combustion and reported symptoms suggestive of preeclampsia/eclampsia in a large nationally representative sample of Indian women and we observed increased risk. These findings have important program and policy implications for countries such as India, where large proportions of the population rely on polluting biomass fuels for cooking and space heating. More epidemiological research with detailed exposure assessments and clinical measures of preeclampsia/eclampsia is needed in a developing country setting to validate these findings. PMID:25039812

Designing Alkaline Exchange Membranes from Scratch

DTIC Science & Technology

2011-10-10

convenient liquid fuels. While there have been some dramatic early achievements, there is still a need for a fundamental study of 1. REPORT DATE (DD-MM...inexpensive metal catalysts and the oxidation of a variety of convenient liquid fuels. While there have been some dramatic early achievements, there is...use of inexpensive metal catalysts and the oxidation of a variety of convenient liquid fuels. While there have been some dramatic early achievements

Ethanol content concerns in motor gasoline (mogas) in aviation in comparison to aviation gasoline (avgas)

NASA Astrophysics Data System (ADS)

Thanikasalam, K.; Rahmat, M.; Fahmi, A. G. Mohammad; Zulkifli, A. M.; Shawal, N. Noor; Ilanchelvi, K.; Ananth, M.; Elayarasan, R.

2018-05-01

Mogas has been an alternative to leaded fuel since 1964 when Experimental Aircraft Association (EAA) began testing on it. However, in order for mogas to be used in aircraft engines and air frame modification, approval via the Supplemental Type Certificate (STC) authorization from Federal Aviation Administration (FAA) is mandatory. Cessna on 01.06.2010 evaluated alternative fuels with ethanol based fuels approved by FAA STCs for use in some single engine airplanes. However, Cessna’s tests discovered that ethanol based gasoline cannot be viewed as an option to 100LL avgas. The test likewise proposed that operational safety might be in jeopardy if usage of these fuels containing ethanol is continued. Cessna outlined a few problems in MOGAS; MOGAS needs fuel flow increase of 40% compared to AVGAS, MOGAS fuel is incompatible with some fuel system components, possible hazardous influence of electric fuel pumps by adding internal wear causing unexpected spark generation, MOGAS is incompatible with some fuel gauging systems and cause be able to incorrect fuel amount signs on the indicator, dissolve large amounts of water at conditions down to -77°F, impeding detection and removal of water from the fuel system, possible blockage of fuel filters and fuel flow and possible heavy losses from evaporation. This paper reviews concerns when using MOGAS in aircraft.

Hydrogen generation from natural gas for the fuel cell systems of tomorrow

NASA Astrophysics Data System (ADS)

Dicks, Andrew L.

In most cases hydrogen is the preferred fuel for use in the present generation of fuel cells being developed for commercial applications. Of all the potential sources of hydrogen, natural gas offers many advantages. It is widely available, clean, and can be converted to hydrogen relatively easily. When catalytic steam reforming is used to generate hydrogen from natural gas, it is essential that sulfur compounds in the natural gas are removed upstream of the reformer and various types of desulfurisation processes are available. In addition, the quality of fuel required for each type of fuel cell varies according to the anode material used, and the cell temperature. Low temperature cells will not tolerate high concentrations of carbon monoxide, whereas the molten fuel cell (MCFC) and solid oxide fuel cell (SOFC) anodes contain nickel on which it is possible to electrochemically oxidise carbon monoxide directly. The ability to internally reform fuel gas is a feature of the MCFC and SOFC. Internal reforming can give benefits in terms of increased electrical efficiency owing to the reduction in the required cell cooling and therefore parasitic system losses. Direct electrocatalysis of hydrocarbon oxidation has been the elusive goal of fuel cell developers over many years and recent laboratory results are encouraging. This paper reviews the principal methods of converting natural gas into hydrogen, namely catalytic steam reforming, autothermic reforming, pyrolysis and partial oxidation; it reviews currently available purification techniques and discusses some recent advances in internal reforming and the direct use of natural gas in fuel cells.

Alternative Fuels and Their Potential Impact on Aviation

NASA Technical Reports Server (NTRS)

Daggett, D.; Hendricks, R.; Walther, R.

2006-01-01

With a growing gap between the growth rate of petroleum production and demand, and with mounting environmental needs, the aircraft industry is investigating issues related to fuel availability, candidates for alternative fuels, and improved aircraft fuel efficiency. Bio-derived fuels, methanol, ethanol, liquid natural gas, liquid hydrogen, and synthetic fuels are considered in this study for their potential to replace or supplement conventional jet fuels. Most of these fuels present the airplane designers with safety, logistical, and performance challenges. Synthetic fuel made from coal, natural gas, or other hydrocarbon feedstock shows significant promise as a fuel that could be easily integrated into present and future aircraft with little or no modification to current aircraft designs. Alternatives, such as biofuel, and in the longer term hydrogen, have good potential but presently appear to be better suited for use in ground transportation. With the increased use of these fuels, a greater portion of a barrel of crude oil can be used for producing jet fuel because aircraft are not as fuel-flexible as ground vehicles.

Regional analysis of renewable transportation fuels - production and consumption

NASA Astrophysics Data System (ADS)

Liu, Xiaoshuai

The transportation sector contributes more than a quarter of total U.S. greenhouse gas emissions. Replacing fossil fuels with renewable fuels can be a key solution to mitigate GHG emissions from the transportation sector. Particularly, we have focused on land-based production of renewable fuels from landfills and brownfield in the southeastern region of the United States. These so call marginal lands require no direct land-use change to avoid environmental impact and, furthermore, have rendered opportunities for carbon trading and low-carbon intensity business. The resources potential and production capacity were derived using federal and state energy databases with the aid of GIS techniques. To maximize fuels production and land-use efficiency, a scheme of co-location renewable transportation fuels for production on landfills was conducted as a case study. Results of economic modeling analysis indicate that solar panel installed on landfill sites could generate a positive return within the project duration, but the biofuel production within the landfill facility is relatively uncertain, requiring proper sizing of the onsite processing facility, economic scale of production and available tax credits. From the consumers' perspective, a life-cycle cost analysis has been conducted to determine the economic and environmental implications of different transportation choices by consumers. Without tax credits, only the hybrid electric vehicles have lifetime total costs equivalent to a conventional vehicles differing by about 1 to 7%. With tax credits, electric and hybrid electric vehicles could be affordable and attain similar lifetime total costs as compared to conventional vehicles. The dissertation research has provided policy-makers and consumers a pathway of prioritizing investment on sustainable transportation systems with a balance of environmental benefits and economic feasibility.

Chemical Dissolution of Simulant FCA Cladding and Plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, G.; Pierce, R.; O'Rourke, P.

The Savannah River Site (SRS) has received some fast critical assembly (FCA) fuel from the Japan Atomic Energy Agency (JAEA) for disposition. Among the JAEA FCA fuel are approximately 7090 rectangular Stainless Steel clad fuel elements. Each element has an internal Pu-10.6Al alloy metal wafer. The thickness of each element is either 1/16 inch or 1/32 inch. The dimensions of each element ranges from 2 inches x 1 inch to 2 inches x 4 inches. This report discusses the potential chemical dissolution of the FCA clad material or stainless steel. This technology uses nitric acid-potassium fluoride (HNO 3-KF) flowsheets ofmore » H-Canyon to dissolve the FCA elements from a rack of materials. Historically, dissolution flowsheets have aimed to maximize Pu dissolution rates while minimizing stainless steel dissolution (corrosion) rates. Because the FCA cladding is made of stainless steel, this work sought to accelerate stainless steel dissolution.« less

Utilization of ventilation air methane as a supplementary fuel at a circulating fluidized bed combustion boiler.

PubMed

You, Changfu; Xu, Xuchang

2008-04-01

Ventilation air methane (VAM) accounts for 60-80% of the total emissions from coal mining activities in China, which is of serious greenhouse gas concerns as well as a waste of valuable fuel sources. This contribution evaluates the use of the VAM utilization methods as a supplementary fuel at a circulating fluidized bed combustion boiler. The paper describes the system design and discusses some potential technical challenges such as methane oxidation rate, corrosion, and efficiency. Laboratory experimentation has shown that the VAM can be burnt completely in circulated fluidized bed furnaces, and the VAM oxidation does not obviously affect the boiler operation when the methane concentration is less than 0.6%. The VAM decreased the incomplete combustion loss for the circulating fluidized bed combustion furnace. The economic benefit from the coal saving insures that the proposed system is more economically feasible.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cramer, Alisha J.; Cole, Jacqueline M.

The ever-increasing demands of the modern world continue to place substantial strain on the environment. To help alleviate the damage done to the natural world, the encapsulation of small molecules or ions (guests) into porous inorganic structural frameworks (hosts) provides a potential remedy for some of the environmental concerns facing us today. These concerns include the removal of harmful pollutants from water or air, the safe entrapment of nuclear waste materials, or the purification and storage of small molecules that act as alternative fuel sources. For this study, we review the trends in using inorganic materials as hostmedia for themore » removal or storage of various wastes and alternative fuels. In conclusion, we cover the treatment of water contaminated with dyes or heavy metals, air pollution alleviation via CO 2, SO x, NO x, and volatile organic compound containment, nuclear waste immobilization, and storage for H 2 and methane as alternative fuels.« less

CORROSION STUDIES FOR A FUSED SALT-LIQUID METAL EXTRACTION PROCESS FOR THE LIQUID METAL FUEL REACTOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Susskind, H.; Hill, F.B.; Green, L.

1960-06-30

Corrosion screening tests were carried out on potential materials of construction for use in a fused salt-liquid metal extraction process plant. The corrodents of interest were NaCl--KCl-- MgCl/sub 2/ eutectic, LiCl--KCl eutectic, Bi-- U fuel, and BiCl/sub 3/, either separately or in various combinations. Screening tests to determine the resistance of a wide range of commercial alloys to the corrodents were performed in static and tilting-furnace capsules. Some ceramic materials were tested in static capsules. Largerscale tests of metallic materials were conducted in thermal convection loops and in a forced circulation loop. Some of the tests were conducted isothermally atmore » 500 deg C, and others were performed under 40 to 50 deg C temperature differences at roughly the same teinperature level. On the basis of metallographic examination of exposed test tabs and chemical analyses of corrodents, it was found that the binary and ternary eutectics by themselves produced little attack on any of the materials tested. A wide variety of materials including 1020 mild steel, 2 1/4 Cr--1 Mo alloy steel, types 304 (ELC), 310, 316, 347, 430, and 446 stainless steel, 16-1 Croloy, Inconel, Hastelloy C, Inor-8, Mo, and Ta is, therefore, available for further study. Corrosion by the ternary salt-fuel system was characteristic of that produced by the fuel alone. Alloys such as 1020 mild steel, and 1 1/4 Cr--1/ 2 Mo, and 2 1/4 Cr--1 Mo alloy steel, which are resistant to fuel, would be likely choices at present for container materials. BiCl/sub 3/ produced extensive attack on ternary salt-fuel containers when the fuel contained insufficient concentrations of oxidizable solutes. Au and Al/sub 2/O/sub 3/ were the only materials not attacked by BiCl/sub 3/ in ternary salt alone. (auth)« less

Correlation for the estimation of the density of fatty acid esters fuels and its implications. A proposed Biodiesel Cetane Index.

PubMed

Lapuerta, Magín; Rodríguez-Fernández, José; Armas, Octavio

2010-09-01

Biodiesel fuels (methyl or ethyl esters derived from vegetables oils and animal fats) are currently being used as a means to diminish the crude oil dependency and to limit the greenhouse gas emissions of the transportation sector. However, their physical properties are different from traditional fossil fuels, this making uncertain their effect on new, electronically controlled vehicles. Density is one of those properties, and its implications go even further. First, because governments are expected to boost the use of high-biodiesel content blends, but biodiesel fuels are denser than fossil ones. In consequence, their blending proportion is indirectly restricted in order not to exceed the maximum density limit established in fuel quality standards. Second, because an accurate knowledge of biodiesel density permits the estimation of other properties such as the Cetane Number, whose direct measurement is complex and presents low repeatability and low reproducibility. In this study we compile densities of methyl and ethyl esters published in literature, and proposed equations to convert them to 15 degrees C and to predict the biodiesel density based on its chain length and unsaturation degree. Both expressions were validated for a wide range of commercial biodiesel fuels. Using the latter, we define a term called Biodiesel Cetane Index, which predicts with high accuracy the Biodiesel Cetane Number. Finally, simple calculations prove that the introduction of high-biodiesel content blends in the fuel market would force the refineries to reduce the density of their fossil fuels. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

Method for improving the fuel efficiency of a gas turbine engine

NASA Technical Reports Server (NTRS)

Coffinberry, G. A. (Inventor)

1985-01-01

An energy recovery system is provided for an aircraft gas turbine engine of the type in which some of the pneumatic energy developed by the engine is made available to support systems such as an environmental control system. In one such energy recovery system, some of the pneumatic energy made available to but not utilized by the support system is utilized to heat the engine fuel immediately prior to the consumption of the fuel by the engine. Some of the recovered energy may also be utilized to heat the fuel in the fuel tanks. Provision is made for multiengine applications wherein energy recovered from one engine may be utilized by another one of the engines or systems associated therewith.

Apparatus for improving the fuel efficiency of a gas turbine engine

NASA Technical Reports Server (NTRS)

Coffinberry, G. A. (Inventor)

1983-01-01

An energy recovery system is provided for an aircraft gas turbine engine of the type in which some of the pneumatic energy developed by the engine is made available to support systems such as an environmental control system. In one such energy recovery system, some of the pneumatic energy made available to but not utilized by the support system is utilized to heat the engine fuel immediately prior to the consumption of the fuel by the engine. Some of the recovered energy may also be utilized to heat the fuel in the fuel tanks. Provision is made for multiengine applications wherein energy recovered from one engine may be utilized by another one of the engines or systems associated therewith.

%22Trojan Horse%22 strategy for deconstruction of biomass for biofuels production.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Blake Alexander; Sinclair, Michael B.; Yu, Eizadora

2011-02-01

Production of renewable biofuels to displace fossil fuels currently consumed in the transportation sector is a pressing multiagency national priority (DOE/USDA/EERE). Currently, nearly all fuel ethanol is produced from corn-derived starch. Dedicated 'energy crops' and agricultural waste are preferred long-term solutions for renewable, cheap, and globally available biofuels as they avoid some of the market pressures and secondary greenhouse gas emission challenges currently facing corn ethanol. These sources of lignocellulosic biomass are converted to fermentable sugars using a variety of chemical and thermochemical pretreatments, which disrupt cellulose and lignin cross-links, allowing exogenously added recombinant microbial enzymes to more efficiently hydrolyzemore » the cellulose for 'deconstruction' into glucose. This process is plagued with inefficiencies, primarily due to the recalcitrance of cellulosic biomass, mass transfer issues during deconstruction, and low activity of recombinant deconstruction enzymes. Costs are also high due to the requirement for enzymes and reagents, and energy-intensive cumbersome pretreatment steps. One potential solution to these problems is found in synthetic biology-engineered plants that self-produce a suite of cellulase enzymes. Deconstruction can then be integrated into a one-step process, thereby increasing efficiency (cellulose-cellulase mass-transfer rates) and reducing costs. The unique aspects of our approach are the rationally engineered enzymes which become Trojan horses during pretreatment conditions. During this study we rationally engineered Cazy enzymes and then integrated them into plant cells by multiple transformation techniques. The regenerated plants were assayed for first expression of these messages and then for the resulting proteins. The plants were then subjected to consolidated bioprocessing and characterized in detail. Our results and possible implications of this work on developing dedicated energy crops and their advantage in a consolidated bioprocessing system.« less

One dimensional modeling of a diesel-CNG dual fuel engine

NASA Astrophysics Data System (ADS)

Azman, Putera Adam; Fawzi, Mas; Ismail, Muammar Mukhsin; Osman, Shahrul Azmir

2017-04-01

Some of the previous studies have shown that the use of compressed natural gas (CNG) in diesel engines potentially produce engine performance improvement and exhaust gas emission reduction, especially nitrogen oxides, unburned hydrocarbons, and carbon dioxide. On the other hand, there are other researchers who claimed that the use of CNG increases exhaust gas emissions, particularly nitrogen oxides. In this study, a one-dimensional model of a diesel-CNG dual fuel engine was made based on a 4-cylinder 2.5L common rail direct injection diesel engine. The software used is GT-Power, and it was used to analyze the engine performance and exhaust gas emissions of several diesel-CNG dual fuel blend ratios, i.e. 100:0, 90:10, 80:20, 70:30, 60:40 and 50:50. The effect of 100%, 75%, 50% engine loads on the exhaust gas emissions were also studied. The result shows that all diesel-CNG fuel blends produces higher brake torque and brake power at engine speed of 2000-3000 rpm compared with 100% diesel. The 50:50 diesel-CNG blend produces the highest brake torque and brake power, but also has the highest brake specific fuel consumption. As a higher percentage of CNG added to the dual fuel blend, unburned hydrocarbons and carbon monoxide emission increased while carbon dioxide emission decreased. The nitrogen oxides emission concentration is generally unaffected by any change of the dual fuel ratio.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vimmerstedt, Laura; Brown, Austin; Newes, Emily

The transportation sector is changing, influenced by concurrent, ongoing, dynamic trends that could dramatically affect the future energy landscape, including effects on the potential for greenhouse gas emissions reductions. Battery cost reductions and improved performance coupled with a growing number of electric vehicle model offerings are enabling greater battery electric vehicle market penetration, and advances in fuel cell technology and decreases in hydrogen production costs are leading to initial fuel cell vehicle offerings. Radically more efficient vehicles based on both conventional and new drivetrain technologies reduce greenhouse gas emissions per vehicle-mile. Net impacts also depend on the energy sources usedmore » for propulsion, and these are changing with increased use of renewable energy and unconventional fossil fuel resources. Connected and automated vehicles are emerging for personal and freight transportation systems and could increase use of low- or non-emitting technologies and systems; however, the net effects of automation on greenhouse gas emissions are uncertain. The longstanding trend of an annual increase in transportation demand has reversed for personal vehicle miles traveled in recent years, demonstrating the possibility of lower-travel future scenarios. Finally, advanced biofuel pathways have continued to develop, highlighting low-carbon and in some cases carbon-negative fuel pathways. We discuss the potential for transformative reductions in petroleum use and greenhouse gas emissions through these emerging transportation-sector technologies and trends and present a Clean Transportation Sector Initiative scenario for such reductions, which are summarized in Table ES-1.« less

Carbohydrates as a cerebral metabolic fuel.

PubMed

Evans, M; Amiel, S A

1998-03-01

The human brain is an extremely active metabolic organ with little endogenous stores of energy. It is thus dependent on circulating glucose to fuel metabolism and support cognitive functioning. However there is growing evidence that the human brain is able to utilise other non-glucose fuels during times of glucose lack. We review the evidence for the potential of the human brain to use the alternate fuels lactate and beta-hydroxybutyrate, and some recent studies examining the ability of regions of brain to use non-glucose lipid fuels. The human brain does not seem to have the ability to use the gluconeogenic precursor alanine to any significant degree. Regionality within the brain can be examined in vivo by the use of positron emission tomography, which offers the exciting prospect of studying human brain metabolism in vivo using a simple and non-interventional technique. Increased understanding of the brain's metabolism, the way in which hypoglycaemia is recognised and the manner in which this can be altered in the syndrome of hypoglycaemia unawareness and deficient counterregulation will help develop further strategies to prevent the clinical problems associated with hypoglycaemia in insulin-dependent diabetic adults and children.

Fuel clad chemical interactions in fast reactor MOX fuels

NASA Astrophysics Data System (ADS)

Viswanathan, R.

2014-01-01

Clad corrosion being one of the factors limiting the life of a mixed-oxide fast reactor fuel element pin at high burn-up, some aspects known about the key elements (oxygen, cesium, tellurium, iodine) in the clad-attack are discussed and many Fuel-Clad-Chemical-Interaction (FCCI) models available in the literature are also discussed. Based on its relatively superior predictive ability, the HEDL (Hanford Engineering Development Laboratory) relation is recommended: d/μm = ({0.507 ṡ [B/(at.% fission)] ṡ (T/K-705) ṡ [(O/M)i-1.935]} + 20.5) for (O/M)i ⩽ 1.98. A new model is proposed for (O/M)i ⩾ 1.98: d/μm = [B/(at.% fission)] ṡ (T/K-800)0.5 ṡ [(O/M)i-1.94] ṡ [P/(W cm-1)]0.5. Here, d is the maximum depth of clad attack, B is the burn-up, T is the clad inner surface temperature, (O/M)i is the initial oxygen-to-(uranium + plutonium) ratio, and P is the linear power rating. For fuels with [n(Pu)/n(M = U + Pu)] > 0.25, multiplication factors f are recommended to consider the potential increase in the depth of clad-attack.

Potential Fuel Economy Improvements from the Implementation of cEGR and CDA on an Atkinson Cycle Engine

EPA Science Inventory

Present the implementation of cEGR and CDA on an Atkinson engine and use steady state fuel consumption maps to estimate the technologies’ potential fuel economy improvements over the FTP and Highway tests. In addition to use fuel weighted modes to determine possible fuel economy...

Hydrocarbon emission fingerprints from contemporary vehicle/engine technologies with conventional and new fuels

NASA Astrophysics Data System (ADS)

Montero, Larisse; Duane, Matthew; Manfredi, Urbano; Astorga, Covadonga; Martini, Giorgio; Carriero, Massimo; Krasenbrink, Alois; Larsen, B. R.

2010-06-01

The present paper presents results from the analysis of 29 individual C 2-C 9 hydrocarbons (HCs) specified in the European Commission Ozone Directive. The 29 HCs are measured in exhaust from common, contemporary vehicle/engine/fuel technologies for which very little or no data is available in the literature. The obtained HC emission fingerprints are compared with fingerprints deriving from technologies that are being phased out in Europe. Based on the total of 138 emission tests, thirteen type-specific fingerprints are extracted (Mean ± SD percentage contributions from individual HCs to the total mass of the 29 HCs), essential for receptor modelling source apportionment. The different types represent exhaust from Euro3 and Euro4 light-duty (LD) diesel and petrol-vehicles, Euro3 heavy-duty (HD) diesel exhaust, and exhaust from 2-stroke preEuro, Euro1 and Euro2 mopeds. The fuels comprise liquefied petroleum gas, petrol/ethanol blends (0-85% ethanol), and mineral diesel in various blends (0-100%) with fatty acid methyl esters, rapeseed methyl esters palm oil methyl esters, soybean oil methyl or sunflower oil methyl esters. Type-specific tracer compounds (markers) are identified for the various vehicle/engine/fuel technologies. An important finding is an insignificant effect on the HC fingerprints of varying the test driving cycle, indicating that combining HC fingerprints from different emission studies for receptor modelling purposes would be a robust approach. The obtained results are discussed in the context of atmospheric ozone formation and health implications from emissions (mg km -1 for LD and mopeds and mg kW h -1 for HD, all normalised to fuel consumption: mg dm -3 fuel) of the harmful HCs, benzene and 1,3-butadiene. Another important finding is a strong linear correlation of the regulated "total" hydrocarbon emissions (tot-HC) with the ozone formation potential of the 29 HCs (ΣPO 3 = (1.66 ± 0.04) × tot-RH; r2 = 0.93). Tot-HC is routinely monitored in emission control laboratories, whereas C 2-C 9 are not. The revealed strong correlations broadens the usability of data from vehicle emission control laboratories and facilitates the comparison of the ozone formation potential of HCs in exhaust from of old and new vehicle/engine/fuel technologies.

Modeling hazardous fire potential within a completed fuel treatment network in the northern Sierra Nevada

Treesearch

Brandon M. Collins; Heather A. Kramer; Kurt Menning; Colin Dillingham; David Saah; Peter A. Stine; Scott L. Stephens

2013-01-01

We built on previous work by performing a more in-depth examination of a completed landscape fuel treatment network. Our specific objectives were: (1) model hazardous fire potential with and without the treatment network, (2) project hazardous fire potential over several decades to assess fuel treatment network longevity, and (3) assess fuel treatment effectiveness and...

Managing the Nuclear Fuel Cycle: Policy Implications of Expanding Global Access to Nuclear Power

DTIC Science & Technology

2008-09-03

Spent nuclear fuel disposal has remained the most critical aspect of the nuclear fuel cycle for the United States, where longstanding nonproliferation...inalienable right and by and large, neither have U.S. government officials. However, the case of Iran raises perhaps the most critical question in...the enrichment process can take advantage of the slight difference in atomic mass between 235U and 238U. The typical enrichment process requires

Managing the Nuclear Fuel Cycle: Policy Implications of Expanding Global Access to Nuclear Power

DTIC Science & Technology

2008-01-20

critical aspect of the nuclear fuel cycle for the United States, where longstanding nonproliferation policy discouraged commercial nuclear fuel...have U.S. government officials. However, the case of Iran raises perhaps the most critical question in this decade for strengthening the nuclear...slight difference in atomic mass between 235U and 238U. The typical enrichment process requires about 10 lbs of uranium U3O8 to produce 1 lb of low

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, S. L.; Harp, J. M.; Chichester, H. J. M.

Research and development activities on metallic fuels in the US are focused on their potential use for actinide transmutation in future sodium fast reactors. As part of this application, there is a desire to demonstrate a multifold increase in burnup potential. A number of metallic fuel design innovations are under investigation with a view toward significantly increasing the burnup potential of metallic fuels, since higher discharge burnups equate to lower potential actinide losses during recycle. Promising innovations under investigation include: 1) lowering the fuel smeared density in order to accommodate the additional swelling expected as burnups increase, 2) utilizing anmore » annular fuel geometry for better geometrical stability at low smeared densities, as well as the potential to eliminate the need for a sodium bond, and 3) minor alloy additions to immobilize lanthanide fission products inside the metallic fuel matrix and prevent their transport to the cladding resulting in fuel-cladding chemical interaction. This paper presents results from these efforts to advance metallic fuel technology in support of high burnup and actinide transmutation objectives. Highlights include examples of fabrication of low smeared density annular metallic fuels, experiments to identify alloy additions effective in immobilizing lanthanide fission products, and early postirradiation examinations of annular metallic fuels having low smeared densities and palladium additions for fission product immobilization.« less

Important properties of bamboo pellets to be used as commercial solid fuel in China

Treesearch

Zhijia Liu; Benhua Fei; Zehui Jiang; Zhiyong Cai; Xing' e Liu

2014-01-01

Bamboo is a type of biomass material and has great potential as a bioenergy resource of the future in China. Some properties of bamboo pellets, length, diameter, moisture content (MC), particle density, bulk density, durability, fine content, ash, gross calorific value, combustion rate and heat release rate, were determined and the effects of MC and particle size (PS)...

Integrated process for extraction of wax as a value-added co-product and improved ethanol production by converting both starch and cellulosic components in sorghum grains

USDA-ARS?s Scientific Manuscript database

Grain sorghum is a potential feedstock for fuel ethanol production due to its high starch content, which is equivalent to that of corn, and has been successfully used in several commercial corn ethanol plants in the United States. Some sorghum grain varieties contain significant levels of surface wa...

Nonproliferation Uncertainties, a Major Barrier to Used Nuclear Fuel Recycle in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collins, Emory D; Ehinger, Michael H

2011-01-01

A study and comparison of the goals and understandings of nonproliferation authorities with those of used nuclear fuel (UNF) recycle advocates have uncovered (1) some of the basic reasons for the creation of uncertainties by each of the parties, (2) why these uncertainties have become a major barrier to a decision to recycle UNF components in the United States, and (3) what steps can be taken to clarify these uncertainties. Recent papers and viewpoints expressed by nonproliferation authorities and technical consultants were reviewed, summarized, and compared with results of recent fuel cycle systems analyses made at Oak Ridge National Laboratory.more » 1 Similarities and differences were identified, including both technical and policy factors. Nonproliferation authorities and a few UNF recycle advocates have recognized that the reprocessing technologies used for UNF component recycle do not offer significant nonproliferation differences; thus, the methods used can be chosen on some other basis, such as process efficiency, maturity, and/or economics. This paper reviews the safeguards implications beyond the simple assessment of UNF recycle technology selection. Differences in understanding that led to uncertainty barriers to UNF recycle include (1) the vulnerability of unseparated UNF, (2) the effects of time factors on production and accumulation of fissile plutonium isotopes and decay of the ?self-protecting radiation barrier,? (3) the chemistry of UNF components and relative ease of separation, and (4) the significant differences in commercialscale ?safeguards-by-design? UNF recycle facilities and smaller-scale covert operations. Application of safeguards-by-design and engineered safeguards can provide the defense-in-depth necessary for sufficient safeguards. Establishing these requirements for governing acceptable commercial UNF component recycle is essential.« less

Mitochondrial protein hyperacetylation in the failing heart

PubMed Central

Horton, Julie L.; Martin, Ola J.; Lai, Ling; Richards, Alicia L.; Vega, Rick B.; Leone, Teresa C.; Pagliarini, David J.; Muoio, Deborah M.; Bedi, Kenneth C.; Coon, Joshua J.

2016-01-01

Myocardial fuel and energy metabolic derangements contribute to the pathogenesis of heart failure. Recent evidence implicates posttranslational mechanisms in the energy metabolic disturbances that contribute to the pathogenesis of heart failure. We hypothesized that accumulation of metabolite intermediates of fuel oxidation pathways drives posttranslational modifications of mitochondrial proteins during the development of heart failure. Myocardial acetylproteomics demonstrated extensive mitochondrial protein lysine hyperacetylation in the early stages of heart failure in well-defined mouse models and the in end-stage failing human heart. To determine the functional impact of increased mitochondrial protein acetylation, we focused on succinate dehydrogenase A (SDHA), a critical component of both the tricarboxylic acid (TCA) cycle and respiratory complex II. An acetyl-mimetic mutation targeting an SDHA lysine residue shown to be hyperacetylated in the failing human heart reduced catalytic function and reduced complex II–driven respiration. These results identify alterations in mitochondrial acetyl-CoA homeostasis as a potential driver of the development of energy metabolic derangements that contribute to heart failure. PMID:26998524

Mitochondrial protein hyperacetylation in the failing heart.

PubMed

Horton, Julie L; Martin, Ola J; Lai, Ling; Riley, Nicholas M; Richards, Alicia L; Vega, Rick B; Leone, Teresa C; Pagliarini, David J; Muoio, Deborah M; Bedi, Kenneth C; Margulies, Kenneth B; Coon, Joshua J; Kelly, Daniel P

2016-02-01

Myocardial fuel and energy metabolic derangements contribute to the pathogenesis of heart failure. Recent evidence implicates posttranslational mechanisms in the energy metabolic disturbances that contribute to the pathogenesis of heart failure. We hypothesized that accumulation of metabolite intermediates of fuel oxidation pathways drives posttranslational modifications of mitochondrial proteins during the development of heart failure. Myocardial acetylproteomics demonstrated extensive mitochondrial protein lysine hyperacetylation in the early stages of heart failure in well-defined mouse models and the in end-stage failing human heart. To determine the functional impact of increased mitochondrial protein acetylation, we focused on succinate dehydrogenase A (SDHA), a critical component of both the tricarboxylic acid (TCA) cycle and respiratory complex II. An acetyl-mimetic mutation targeting an SDHA lysine residue shown to be hyperacetylated in the failing human heart reduced catalytic function and reduced complex II-driven respiration. These results identify alterations in mitochondrial acetyl-CoA homeostasis as a potential driver of the development of energy metabolic derangements that contribute to heart failure.

Fueling a Third Paradigm of Education: The Pedagogical Implications of Digital, Social and Mobile Media

ERIC Educational Resources Information Center

Pavlik, John V.

2015-01-01

Emerging technologies are fueling a third paradigm of education. Digital, networked and mobile media are enabling a disruptive transformation of the teaching and learning process. This paradigm challenges traditional assumptions that have long characterized educational institutions and processes, including basic notions of space, time, content,…

Efficiency of using solid wood fuels in maple syrup evaporators

Treesearch

Lawrence D. Garrett

1981-01-01

A study of commercial, wood-fired evaporators revealed that normal expected thermal efficiencies are between 35 and 50 percent. The moisture content and quality of wood fuels used and the design and method of firing the evaporator are critical in determining evaporator efficiency and the economic implications of using wood.

Household energy use in Asian cities: Responding to development success

NASA Astrophysics Data System (ADS)

Tyler, Stephen R.

In the past 10-15 years, gains in household income and urban development in many countries in Asia have led to significant shifts in household use of fuels away from traditional, biomass-based household fuels to modern, fossil fuels. These results suggest that, while the global atmospheric emissions implications need further analysis, the local air quality effects of urban household fuel use changes have been positive. These changes also demonstrate improvements in living conditions, particularly for poor women and children most affected by indoor air quality. However, for electricity use, where there is evidence of dramatic increases in household consumption, the longer term implications for atmospheric emissions are more troubling. Rapid demand growth in the urban household sector is contributing to huge increases in thermal electric generating capacity needs in Asia. Improving technologies of electricity use in the household sector appears to be easily achievable and could be stimulated through market and policy mechanisms which have been used elsewhere. These measures offer the prospect of real environmental and economic gains without sacrificing lifestyle advantages of electrical appliance use in households.

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. Wigeland; T. Taiwo; M. Todosow

The recently completed comprehensive evaluation and screening of nuclear fuel cycle options identified a number of potentially promising fuel cycles for R&D that offer what could be considered by decision-makers as having the potential for significant improvement compared to the current U.S. fuel cycle. The fuel cycles that consistently performed the best were recycle fuel cycles that used self-sustaining fast reactors operating with either U/Pu or U/TRU recycle fuel and also included options where the fast reactors provided fissile materials to support operation of thermal reactors. However, based on the evaluation criteria and metrics used in the study, there wasmore » no difference in benefit between recycle of U/Pu and U/TRU (where TRU is plutonium and the minor actinides) while there were differences in the challenges for developing and deploying such fuel cycles, with U/TRU recycle being more challenging. This observation prompted the question as to the desirability of pursuing R&D on U/TRU recycle given that there may not be an increase in benefit. As a result, activities have been pursued to further investigate the performance differences between U/Pu and U/TRU recycle based on considering issues beyond those used in the evaluation and screening study to identify, if possible, areas where there are significant benefits of U/TRU recycle compared to U/Pu recycle. These new considerations focused on several areas, but especially on the impact on disposal of the HLW, which in the case of U/Pu recycle contains all of the minor actinides along with fission products, while in the case of U/TRU recycle only contains the losses of minor actinides from the reprocessing and recycle fuel fabrication operations. This difference in content has several implications. One impact is on the time dependent decay heat which can affect handling and the use of space in a geologic repository. Another impact concerns the HLW form and volume, since presence of minor actinides may adversely affect the ability to reduce HLW volume. The short-term radioactivity and long-term radiotoxicity of the HLW is also affected, which may be of more or less importance depending on the specific geologic disposal environment. To study these potential effects, a range of waste forms and disposal environments were used in the analysis, documenting to what extent the recycle of minor actinides in addition to plutonium may offer further benefit. Another area of investigation concerned the recycle fuel, for the fast reactor and for the thermal reactors they may support. Information to date indicates that U/Pu fuel may be simpler to fabricate and has a much more extensive database than U/TRU fuel, one of the reasons for the increased challenge for developing and deploying a U/TRU fuel cycle, and also indicates that heterogeneous recycle of the minor actinides may be even more difficult as compared to homogeneous recycle. This information was reviewed and updated to reflect the most recent studies for the purpose of informing on all aspects of the differences between U/Pu and U/TRU recycle. The results of all of these investigations will be presented to provide information on the findings concerning the value of U/TRU recycle.« less

Advanced fuel system technology for utilizing broadened property aircraft fuels

NASA Technical Reports Server (NTRS)

Reck, G. M.

1980-01-01

Possible changes in fuel properties are identified based on current trends and projections. The effect of those changes with respect to the aircraft fuel system are examined and some technological approaches to utilizing those fuels are described.

Cumulative emission budgets and their implications: the case for SAFE carbon

NASA Astrophysics Data System (ADS)

Allen, Myles; Bowerman, Niel; Frame, David; Mason, Charles

2010-05-01

The risk of dangerous long-term climate change due to anthropogenic carbon dioxide emissions is predominantly determined by cumulative emissions over all time, not the rate of emission in any given year or commitment period. This has profound implications for climate mitigation policy: emission targets for specific years such as 2020 or 2050 provide no guarantee of meeting any overall cumulative emission budget. By focusing attention on short-term measures to reduce the flow of emissions, they may even exacerbate the overall long-term stock. Here we consider how climate policies might be designed explicitly to limit cumulative emissions to, for example, one trillion tonnes of carbon, a figure that has been estimated to give a most likely warming of two degrees above pre-industrial, with a likely range of 1.6-2.6 degrees. Three approaches are considered: tradable emission permits with the possibility of indefinite emission banking, carbon taxes explicitly linked to cumulative emissions and mandatory carbon sequestration. Framing mitigation policy around cumulative targets alleviates the apparent tension between climate protection and short-term consumption that bedevils any attempt to forge global agreement. We argue that the simplest and hence potentially the most effective approach might be a mandatory requirement on the fossil fuel industry to ensure that a steadily increasing fraction of fossil carbon extracted from the ground is artificially removed from the active carbon cycle through some form of sequestration. We define Sequestered Adequate Fraction of Extracted (SAFE) carbon as a source in which this sequestered fraction is anchored to cumulative emissions, increasing smoothly to reach 100% before we release the trillionth tonne. While adopting the use of SAFE carbon would increase the cost of fossil energy much as a system of emission permits or carbon taxes would, it could do so with much less explicit government intervention. We contrast this proposal with, for example, the WBGU budget approach which also recognises the importance of cumulative emissions, noting their different implications for global equity and development considerations. The implications of cumulative emissions for the issue of historical responsibility for adaptation costs will also be discussed.

Emerging Insights on Brazilian Pepper Tree (Schinus terebinthifolius) Invasion: The Potential Role of Soil Microorganisms

PubMed Central

Dawkins, Karim; Esiobu, Nwadiuto

2016-01-01

Invasive plant species constitute a major ecological and economic problem worldwide, often distorting trophic levels and ecosystem balance. Numerous studies implicate factors ranging from environmental plasticity, competition for nutrient and space, and allelopathy in the success of invasive species in general. The Brazilian Pepper tree (BP) was introduced to the United States in the 1800s and has since become a category one invasive plant in Florida. It has aggressively spread to about 3000 km2 of terrestrial surface, fueled in part by the prevalence of the hybrid genotypes and environmental perturbations. It displays some of the well-established invasive mechanisms but there is a serious dearth of knowledge on the plant–microbe–soil interactions and whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. Several control measures, including chemical, mechanical, and biological antagonism have been used with limited success while restoration of natives in soils from which BP was removed has proved problematic partly due to a poorly understood phenomenon described as the “BP legacy effect.” Emerging evidence suggests that allelopathy, selective recruitment of beneficial soil microbes, disruption of microbial community structure and alteration of nutrient cycling, exhibited by many other invasive plant species may also be involved in the case of BP. This brief review discusses the well-established BP invasion mechanisms and highlights the current understanding of the molecular, below-ground processes. It also points out the gaps in studies on the potential role of microbial interactions in the success of BP invasion. These hitherto poorly studied mechanisms could further explain the aggressive spread of BP and could potentially contribute significantly to effective control measures and enable appropriate strategies for restoring native plants. The review advocates for the use of cutting-edge techniques in advancing the plant microbiome science. Ultimately, comparing metagenomic analyses of the rhizobiome of invasive plants grown in native and non-native soils could lead to a better understanding of the microbial determinants of biotic resistance, potentially empowering environmental managers with some predictive power of future trends of plant invasion. PMID:27252726

The EPA National Fuels Surveillance Network. I. Trace constituents in gasoline and commercial gasoline fuel additives.

PubMed Central

Jungers, R H; Lee, R E; von Lehmden, D J

1975-01-01

A National Fuels Surveillance Network has been established to collect gasoline and other fuels through the 10 regional offices of the Environmental Protection Agency. Physical, chemical, and trace element analytical determinations are made on the collected fuel samples to detect components which may present an air pollution hazard or poison exhaust catalytic control devices. A summary of trace elemental constituents in over 50 gasoline samples and 18 commercially marketed consumer purchased gasoline additives is presented. Quantities of Mn, Ni, Cr, Zn, Cu, Fe, Sb, B, Mg, Pb, and S were found in most regular and premium gasoline. Environmental implications of trace constituents in gasoline are discussed. PMID:1157783

Fuel alcohol: some economic complexities in Brazil and in the United States. Energy in developing countries series: Discussion Paper D-73G. [Monograph

DOE Office of Scientific and Technical Information (OSTI.GOV)

Islam, S.; Ramsay, W.

1982-01-01

Two related papers (one by each author) examine some of the problems and point out some complexities that must be taken into account in evaluating the alcohol option. Islam notes particularly Brazil's dilemma in relinquishing its domination of world sugar markets in favor of fuel-alcohol programs that will offer more resilience to future oil shocks. Ramsay stresses the practicability of alcohol for fuel import replacement compared to other synthetic fuels; he prefers the alcohol-from-grain option, especially when considered within the context of government incentives and availability of idle land. 24 references. (DCK)

Health and social impacts of biomass gasification for household energy in rural China: Assessment from three perspectives and emergent insights from their synthesis

NASA Astrophysics Data System (ADS)

Fischer, Susan Lynn

Solid fuels such as coal, wood, and crop straw supply some fraction of household cooking and heating fuel for more than one billion people in China. As these fuels do not generally combust cleanly in household stoves, their use levies large health and environmental burdens, particularly in rural regions. Production of clean-burning fuels from agricultural residue offers one prospect for mitigating health and social burdens imposed by household use of solid fuels. This dissertation explores the question: how might production of clean-burning household fuels from agricultural residues affect human health and social conditions in rural China? I approach this question from three perspectives. First, a technically plausible but currently unproven village-scale energy technology is explored in a scenario bounded by natural resources and substantiated by engineering specifications, estimates of indoor exposures to air pollution, and epidemiological analyses. This analysis asks at the national (China) level: how might rural health burdens be mitigated and greenhouse gas emissions reduced by such a technology? Secondly, I perform wintertime indoor air quality monitoring in a Chinese village where coal and wood are used for heating and a variety of solid and "improved" fuels, including gas and electricity, are used for cooking. This fieldwork characterizes rural indoor air quality in terms of 24-hour and peak-period (1-hour) carbon monoxide (CO) and particulate matter (PM) concentrations and 24-hour airborne nicotine (a proxy for environmental tobacco smoke), as well as daily exposures of primary cooks to CO. I also explore relationships between observed measures of indoor air quality and investigate household structural and behavioral factors as determinants of air quality. The third perspective is an ethnographic case study of a demonstration project for production of household fuel from agricultural residue in Hechengli Village, Jilin Province, China. With an emphasis on rural residents' and local leaders' perspectives, this field research clarifies local social, economic, and environmental dimensions of the energy project. I consider broader implications for similar rural projects as well as institutional reception of these particular findings. (Abstract shortened by UMI.)

The healing power of prayer and its implications for nursing.

PubMed

Narayanasamy, Aru; Narayanasamy, Mani

Prayer is widely acknowledged in both ancient and modern times as an intervention for alleviating illnesses and promoting good health. There is increasing attention on prayer in health care, in both popular and serious discourse. Advocates exalt the healing power of prayer in health care, while critics are sceptical about this claim and its healing potential is put down to coincidences or its placebo effect. Consequently, a variety of empirical studies have attempted to test its effect scientifically with no conclusive results. There is evidence to suggest that some patients and healthcare practitioners believe in the healing power of prayer. Nurses may be called upon to pray with or for patients as part of holistic care. This article sets out to explore the role of prayer in healing and its implications for nursing. To achieve this aim, this article provides a review of discourses and evidence on the power of prayer in healing. Its implications for nursing are highlighted with some suggestions on how to respond to patients' spiritual needs. It is concluded that, although the evidence on the healing power of spirituality is inconclusive, there are indications that it has potential for the health and wellbeing of both patients and nurses.

Fuel consumption optimization for smart hybrid electric vehicle during a car-following process

NASA Astrophysics Data System (ADS)

Li, Liang; Wang, Xiangyu; Song, Jian

2017-03-01

Hybrid electric vehicles (HEVs) provide large potential to save energy and reduce emission, and smart vehicles bring out great convenience and safety for drivers. By combining these two technologies, vehicles may achieve excellent performances in terms of dynamic, economy, environmental friendliness, safety, and comfort. Hence, a smart hybrid electric vehicle (s-HEV) is selected as a platform in this paper to study a car-following process with optimizing the fuel consumption. The whole process is a multi-objective optimal problem, whose optimal solution is not just adding an energy management strategy (EMS) to an adaptive cruise control (ACC), but a deep fusion of these two methods. The problem has more restricted conditions, optimal objectives, and system states, which may result in larger computing burden. Therefore, a novel fuel consumption optimization algorithm based on model predictive control (MPC) is proposed and some search skills are adopted in receding horizon optimization to reduce computing burden. Simulations are carried out and the results indicate that the fuel consumption of proposed method is lower than that of the ACC+EMS method on the condition of ensuring car-following performances.

Health impact assessment of liquid biofuel production.

PubMed

Fink, Rok; Medved, Sašo

2013-01-01

Bioethanol and biodiesel as potential substitutes for fossil fuels in the transportation sector have been analyzed for environmental suitability. However, there could be impacts on human health during the production, therefore adverse health effects have to be analyzed. The aim of this study is to analyze to what health risk factors humans are exposed to in the production of biofuels and what the size of the health effects is. A health impact assessment expressed as disability adjusted life years (DALYs) was conducted in SimaPro 7.1 software. The results show a statistically significant lower carcinogenic impact of biofuels (p < 0.05) than fossil fuels. Meanwhile, the impact of organic respirable compounds is smaller for fossil fuels (p < 0.05) than for biofuels. Analysis of inorganic compounds like PM₁₀,₂.₅, SO₂ or NO(x) shows some advantages of sugar beet bioethanol and soybean biodiesel production (p < 0.05), although production of sugarcane bioethanol shows larger impacts of respirable inorganic compounds than for fossil fuels (p < 0.001). Although liquid biofuels are made of renewable energy sources, this does not necessary mean that they do not represent any health hazards.

Scenarios towards limiting global mean temperature increase below 1.5 °C

NASA Astrophysics Data System (ADS)

Rogelj, Joeri; Popp, Alexander; Calvin, Katherine V.; Luderer, Gunnar; Emmerling, Johannes; Gernaat, David; Fujimori, Shinichiro; Strefler, Jessica; Hasegawa, Tomoko; Marangoni, Giacomo; Krey, Volker; Kriegler, Elmar; Riahi, Keywan; van Vuuren, Detlef P.; Doelman, Jonathan; Drouet, Laurent; Edmonds, Jae; Fricko, Oliver; Harmsen, Mathijs; Havlík, Petr; Humpenöder, Florian; Stehfest, Elke; Tavoni, Massimo

2018-04-01

The 2015 Paris Agreement calls for countries to pursue efforts to limit global-mean temperature rise to 1.5 °C. The transition pathways that can meet such a target have not, however, been extensively explored. Here we describe scenarios that limit end-of-century radiative forcing to 1.9 W m-2, and consequently restrict median warming in the year 2100 to below 1.5 °C. We use six integrated assessment models and a simple climate model, under different socio-economic, technological and resource assumptions from five Shared Socio-economic Pathways (SSPs). Some, but not all, SSPs are amenable to pathways to 1.5 °C. Successful 1.9 W m-2 scenarios are characterized by a rapid shift away from traditional fossil-fuel use towards large-scale low-carbon energy supplies, reduced energy use, and carbon-dioxide removal. However, 1.9 W m-2 scenarios could not be achieved in several models under SSPs with strong inequalities, high baseline fossil-fuel use, or scattered short-term climate policy. Further research can help policy-makers to understand the real-world implications of these scenarios.

Impact of ETO propellants on the aerothermodynamic analyses of propulsion components

NASA Technical Reports Server (NTRS)

Civinskas, K. C.; Boyle, R. J.; Mcconnaughey, H. V.

1988-01-01

The operating conditions and the propellant transport properties used in Earth-to-Orbit (ETO) applications affect the aerothermodynamic design of ETO turbomachinery in a number of ways. Some aerodynamic and heat transfer implications of the low molecular weight fluids and high Reynolds number operating conditions on future ETO turbomachinery are discussed. Using the current SSME high pressure fuel turbine as a baseline, the aerothermodynamic comparisons are made for two alternate fuel turbine geometries. The first is a revised first stage rotor blade designed to reduce peak heat transfer. This alternate design resulted in a 23 percent reduction in peak heat transfer. The second design concept was a single stage rotor to yield the same power output as the baseline two stage rotor. Since the rotor tip speed was held constant, the turbine work factor doubled. In this alternate design, the peak heat transfer remained the same as the baseline. While the efficiency of the single stage design was 3.1 points less than the baseline two stage turbine, the design was aerothermodynamically feasible, and may be structurally desirable.

A review of the clinical implications of bisphosphonates in dentistry.

PubMed

Borromeo, G L; Tsao, C E; Darby, I B; Ebeling, P R

2011-03-01

Bisphosphonates are drugs that suppress bone turnover and are commonly prescribed to prevent skeletal related events in malignancy and for benign bone diseases such as osteoporosis. Bisphosphonate associated jaw osteonecrosis (ONJ) is a potentially debilitating, yet poorly understood condition. A literature review was undertaken to review the dental clinical implications of bisphosphonates. The present paper briefly describes the postulated pathophysiology of ONJ and conditions with similar clinical presentations. The implications of bisphosphonates for implantology, periodontology, orthodontics and endodontics are reviewed. Whilst bisphosphonates have potential positive applications in some clinical settings, periodontology particularly, further clinical research is limited by the risk of ONJ. Prevention and management are reviewed, including guidelines for reducing cumulative intravenous bisphosphonate dose, cessation of bisphosphonates prior to invasive dental treatment or after ONJ development, and the use of serum beta-CTX-1 in assessing risk. In the context of substantial uncertainty, the implications of bisphosphonate use in the dental clinical setting are still being determined. © 2010 Australian Dental Association.

An assessment of the crash fire hazard of liquid hydrogen fueled aircraft

NASA Technical Reports Server (NTRS)

1982-01-01

The crash fire hazards of liquid hydrogen fueled aircraft relative to those of mission equivalent aircraft fueled either with conventional fuel or with liquefied methane were evaluated. The aircraft evaluated were based on Lockheed Corporation design for 400 passenger, Mach 0.85, 5500 n. mile aircraft. Four crash scenarios were considered ranging from a minor incident causing some loss of fuel system integrity to a catastrophic crash. Major tasks included a review of hazardous properties of the alternate fuels and of historic crash fire data; a comparative hazard evluation for each of the three fuels under four crash scenarios a comprehensive review and analysis and an identification of areas further development work. The conclusion was that the crash fire hazards are not significantly different when compared in general for the three fuels, although some fuels showed minor advantages in one respect or another.

Global Climate Change: Some Implications, Opportunities, and Challenges for US Forestry

DOE R&D Accomplishments Database

Marland, G.

1991-06-01

It is widely agreed that the concentration of greenhouse gases in the earth`s atmosphere is increasing, that this increase is a consequence of man`s activities, and that there is significant risk that this will lead to changes in the earth`s climate. The question is now being discussed what, if anything, we should be doing to minimize and/or adapt to changes in climate. Virtually every statement on this matter; from the US Office of Technology Assessment, to the National Academy of Science, to the Nairobi Declaration on Climatic Change, includes some recommendation for planting and protecting forests. In fact, forestry is intimately involved in the climate change debate for several reasons: changing climate patterns will affect existing forests, tropical deforestation is one of the major sources of greenhouse gases to the atmosphere, reforestation projects could remove additional carbon dioxide from the atmosphere and there is renewed interest in wood-based or other renewable fuels to replace fossil fuels. Part of the enthusiasm for forestry-related strategies in a greenhouse context is the perception that forests not only provide greenhouse benefits but also serve other desirable social objectives. This discussion will explore the current range of thinking in this area and try to stimulate additional thinking on the rationality of the forestry-based approaches and the challenges posed for US forestry.

Squeezing through the Now-or-Never bottleneck: Reconnecting language processing, acquisition, change, and structure.

PubMed

Chater, Nick; Christiansen, Morten H

2016-01-01

If human language must be squeezed through a narrow cognitive bottleneck, what are the implications for language processing, acquisition, change, and structure? In our target article, we suggested that the implications are far-reaching and form the basis of an integrated account of many apparently unconnected aspects of language and language processing, as well as suggesting revision of many existing theoretical accounts. With some exceptions, commentators were generally supportive both of the existence of the bottleneck and its potential implications. Many commentators suggested additional theoretical and linguistic nuances and extensions, links with prior work, and relevant computational and neuroscientific considerations; some argued for related but distinct viewpoints; a few, though, felt traditional perspectives were being abandoned too readily. Our response attempts to build on the many suggestions raised by the commentators and to engage constructively with challenges to our approach.

Bioprocessing of Stichococcus bacillaris strain siva2011.

PubMed

Sivakumar, Ganapathy; Jeong, Kwangkook; Lay, Jackson O

2014-01-01

Globally, the development of a cost-effective long-term renewable energy infrastructure is one of the most challenging problems faced by society today. Microalgae are rich in potential biofuel substrates such as lipids, including triacylglycerols (TAGs). Some of these algae also biosynthesize small molecule hydrocarbons. These hydrocarbons can often be used as liquid fuels, often with more versatility and by a more direct approach than some TAGs. However, the appropriate TAGs, accumulated from microalgae biomass, can be used as substrates for different kinds of renewable liquid fuels such as biodiesel and jet fuel. This article describes the isolation and identification of a lipid-rich, hydrocarbon-producing alga, Stichococcus bacillaris strain siva2011, together with its bioprocessing, hydrocarbon and fatty acid methyl ester (FAME) profiles. The S. bacillaris strain siva2011 was scaled-up in an 8 L bioreactor with 0.2% CO2. The C16:0, C16:3, C18:1, C18:2 and C18:3 were 112.2, 9.4, 51.3, 74.1 and 69.2 mg/g dry weight (DW), respectively. This new strain produced a significant amount of biomass of 3.79 g/L DW on day 6 in the 8 L bioreactor and also produced three hydrocarbons. A new oil-rich microalga S. bacillaris strain siva2011 was discovered and its biomass has been scaled-up in a newly designed balloon-type bioreactor. The TAGs and hydrocarbons produced by this organism could be used as substrates for jet fuel or biodiesel.

Fuel properties and engine performance of biodiesel from waste cooking oil collected in Dhaka city

NASA Astrophysics Data System (ADS)

Islam, R. B.; Islam, R.; Uddin, M. N.; Ehsan, Md.

2016-07-01

Waste cooking oil can be a potential source of biodiesel that has least effect on the edible oil consumption. Increasing number of hotel-restaurants and more active monitoring by health authorities have increased the generation of waste cooking oil significantly in densely populated cities like Dhaka. If not used or disposed properly, waste cooking oil itself may generate lot of environmental issues. In this work, waste cooking oils from different restaurants within Dhaka City were collected and some relevant properties of these waste oils were measured. Based on the samples studied one with the highest potential as biodiesel feed was identified and processed for engine performance. Standard trans-esterification process was used to produce biodiesel from the selected waste cooking oil. Biodiesel blends of B20 and B40 category were made and tested on a single cylinder direct injection diesel engine. Engine performance parameters included - bhp, bsfc and exhaust emission for rated and part load conditions. Results give a quantitative assessment of the potential of using biodiesel from waste cooking oil as fuel for diesel engines in Bangladesh.

Fuel cell system including a unit for electrical isolation of a fuel cell stack from a manifold assembly and method therefor

DOEpatents

Kelley; Dana A. , Farooque; Mohammad , Davis; Keith

2007-10-02

A fuel cell system with improved electrical isolation having a fuel cell stack with a positive potential end and a negative potential, a manifold for use in coupling gases to and from a face of the fuel cell stack, an electrical isolating assembly for electrically isolating the manifold from the stack, and a unit for adjusting an electrical potential of the manifold such as to impede the flow of electrolyte from the stack across the isolating assembly.

On-site fuel cell field test support program

NASA Astrophysics Data System (ADS)

Staniunas, J. W.; Merten, G. P.

1982-01-01

In order to assess the impact of grid connection on the potential market for fuel cell service, applications studies were conducted to identify the fuel cell operating modes and corresponding fuel cell sizing criteria which offer the most potential for initial commercial service. The market for grid-connected fuel cell service was quantified using United's market analysis program and computerized building data base. Electric and gas consumption data for 268 buildings was added to our surveyed building data file, bringing the total to 407 buildings. These buildings were analyzed for grid-isolated and grid-connected fuel cell service. The results of the analyses indicated that the nursing home, restaurant and health club building sectors offer significant potential for fuel cell service.

The legacy of fossil fuels.

PubMed

Armaroli, Nicola; Balzani, Vincenzo

2011-03-01

Currently, over 80% of the energy used by mankind comes from fossil fuels. Harnessing coal, oil and gas, the energy resources contained in the store of our spaceship, Earth, has prompted a dramatic expansion in energy use and a substantial improvement in the quality of life of billions of individuals in some regions of the world. Powering our civilization with fossil fuels has been very convenient, but now we know that it entails severe consequences. We treat fossil fuels as a resource that anyone anywhere can extract and use in any fashion, and Earth's atmosphere, soil and oceans as a dump for their waste products, including more than 30 Gt/y of carbon dioxide. At present, environmental legacy rather than consistence of exploitable reserves, is the most dramatic problem posed by the relentless increase of fossil fuel global demand. Harmful effects on the environment and human health, usually not incorporated into the pricing of fossil fuels, include immediate and short-term impacts related to their discovery, extraction, transportation, distribution, and burning as well as climate change that are spread over time to future generations or over space to the entire planet. In this essay, several aspects of the fossil fuel legacy are discussed, such as alteration of the carbon cycle, carbon dioxide rise and its measurement, greenhouse effect, anthropogenic climate change, air pollution and human health, geoengineering proposals, land and water degradation, economic problems, indirect effects on the society, and the urgent need of regulatory efforts and related actions to promote a gradual transition out of the fossil fuel era. While manufacturing sustainable solar fuels appears to be a longer-time perspective, alternatives energy sources already exist that have the potential to replace fossil fuels as feedstocks for electricity production. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Outlook for alternative energy sources. [aviation fuels

NASA Technical Reports Server (NTRS)

Card, M. E.

1980-01-01

Predictions are made concerning the development of alternative energy sources in the light of the present national energy situation. Particular emphasis is given to the impact of alternative fuels development on aviation fuels. The future outlook for aircraft fuels is that for the near term, there possibly will be no major fuel changes, but minor specification changes may be possible if supplies decrease. In the midterm, a broad cut fuel may be used if current development efforts are successful. As synfuel production levels increase beyond the 1990's there may be some mixtures of petroleum-based and synfuel products with the possibility of some shale distillate and indirect coal liquefaction products near the year 2000.

The impact of anthropogenic climate change on wildfire across western US forests

NASA Astrophysics Data System (ADS)

Williams, P.; Abatzoglou, J. T.

2016-12-01

Increased forest fire activity across the western United States (US) in recent decades has contributed to widespread forest mortality, carbon emissions, periods of degraded air quality, and substantial fire suppression expenditures. The increase in forest fire activity has likely been enabled by a number of factors including the legacy of fire suppression and human settlement, changes in suppression policies, natural climate variability, and human-caused climate change. We use modeled climate projections to estimate the contribution of anthropogenic climate change to observed increases in eight fuel aridity metrics and forest fire area across the western US. Anthropogenic increases in temperature and vapor pressure deficit have significantly enhanced fuel aridity across western US forests over the past several decades. Comparing observational climate records to records recalculated after removal of modeled anthropogenic trends, we find that anthropogenic climate change accounted for approximately 55% of observed increases in the eight-metric mean fuel aridity during 1979-2015 across western US forests. This implicates anthropogenic climate change as an important driver of observed increases in fuel aridity, and also highlights the importance of natural multi-decadal climate variability in influencing trends in forest fire potential on the timescales of human lives. Based on a very strong (R2 = 0.76) and mechanistically reasonable relationship between interannual variability in the eight-metric mean fuel aridity and forest-fire area in the western US, we estimate that anthropogenic increases in fuel aridity contributed to an additional 4.2 million ha (95% confidence range: 2.7-6.5 million ha) of forest fire area during 1984-2015, nearly doubling the total forest fire area expected in the absence of anthropogenic climate change. The relationship between annual forest fire area and fuel aridity is exponential and the proportion of total forest area burned in a given year has grown rapidly over the past 32 years. Natural climate variability will continue to alternate between modulating and compounding anthropogenic increases in fuel aridity, but anthropogenic climate change has emerged as a chronic driver of increased forest fire activity and should continue to do so where fuels are not limiting.

ADVANCED NUCLEAR FUEL CYCLE EFFECTS ON THE TREATMENT OF UNCERTAINTY IN THE LONG-TERM ASSESSMENT OF GEOLOGIC DISPOSAL SYSTEMS - EBS INPUT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutton, M; Blink, J A; Greenberg, H R

2012-04-25

The Used Fuel Disposition (UFD) Campaign within the Department of Energy's Office of Nuclear Energy (DOE-NE) Fuel Cycle Technology (FCT) program has been tasked with investigating the disposal of the nation's spent nuclear fuel (SNF) and high-level nuclear waste (HLW) for a range of potential waste forms and geologic environments. The planning, construction, and operation of a nuclear disposal facility is a long-term process that involves engineered barriers that are tailored to both the geologic environment and the waste forms being emplaced. The UFD Campaign is considering a range of fuel cycles that in turn produce a range of wastemore » forms. The UFD Campaign is also considering a range of geologic media. These ranges could be thought of as adding uncertainty to what the disposal facility design will ultimately be; however, it may be preferable to thinking about the ranges as adding flexibility to design of a disposal facility. For example, as the overall DOE-NE program and industrial actions result in the fuel cycles that will produce waste to be disposed, and the characteristics of those wastes become clear, the disposal program retains flexibility in both the choice of geologic environment and the specific repository design. Of course, other factors also play a major role, including local and State-level acceptance of the specific site that provides the geologic environment. In contrast, the Yucca Mountain Project (YMP) repository license application (LA) is based on waste forms from an open fuel cycle (PWR and BWR assemblies from an open fuel cycle). These waste forms were about 90% of the total waste, and they were the determining waste form in developing the engineered barrier system (EBS) design for the Yucca Mountain Repository design. About 10% of the repository capacity was reserved for waste from a full recycle fuel cycle in which some actinides were extracted for weapons use, and the remaining fission products and some minor actinides were encapsulated in borosilicate glass. Because the heat load of the glass was much less than the PWR and BWR assemblies, the glass waste form was able to be co-disposed with the open cycle waste, by interspersing glass waste packages among the spent fuel assembly waste packages. In addition, the Yucca Mountain repository was designed to include some research reactor spent fuel and naval reactor spent fuel, within the envelope that was set using the commercial reactor assemblies as the design basis waste form. This milestone report supports Sandia National Laboratory milestone M2FT-12SN0814052, and is intended to be a chapter in that milestone report. The independent technical review of this LLNL milestone was performed at LLNL and is documented in the electronic Information Management (IM) system at LLNL. The objective of this work is to investigate what aspects of quantifying, characterizing, and representing the uncertainty associated with the engineered barrier are affected by implementing different advanced nuclear fuel cycles (e.g., partitioning and transmutation scenarios) together with corresponding designs and thermal constraints.« less

Improved Fossil/Industrial CO2 Emissions Modeling for the North American Carbon Program

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Seib, B.; Mendoza, D.; Knox, S.; Fischer, M.; Murtishaw, S.

2005-05-01

The quantification of fossil fuel CO2 emissions has implications for a wide variety of scientific and policy- related questions. Improvement in inverse-estimated carbon fluxes, country-level carbon budgeting, analysis of regional emissions trading systems, and targeting of observational systems are all important applications better served by improvements in understanding where and when fossil fuel/industrial CO2 is emitted. Traditional approaches to quantifying fossil/industrial CO2 emissions have relied on national sales/consumption of fossil fuels with secondary spatial footprints performed via proxies such as population. This approach has provided global spatiotemporal resolution of one degree/monthly. In recent years the need has arisen for emission estimates that not only achieve higher spatiotemporal scales but include a process- level component. This latter attribute provides dynamic linkages between energy policy/decisionmaking and emissions for use in projecting changes to energy systems and the implications these changes may have on climate change. We have embarked on a NASA-funded research strategy to construct a process-level fossil/industrial CO2 emissions model/database for North America that will resolve fossil/industrial CO2 emissions hourly and at 36 km. This project is a critical component of the North American Carbon Program. Our approach builds off of many decades of air quality monitoring for regulated pollutants such as NOx, VOCs and CO that has been performed by regional air quality managers, states, and the Environmental Protection Agency in the United States. By using the highly resolved monitoring data supplied to the EPA, we have computed CO2 emissions for residential, commercial/industrial, transportation, and biogenic sources. This effort employs a new emissions modeling system (CONCEPT) that spatially and temporally distributes the monitored emissions across the US. We will provide a description of the methodology we have employed, the difficulties encountered and some preliminary results. We will then compare our results to the traditional fossil/industrial CO2 emissions based on national sale/consumption statistics.

Improved Fossil/Industrial CO2 Emissions Modeling for the North American Carbon Program

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Seib, B.; Mendoza, D.; Knox, S.; Fischer, M.; Murtishaw, S.

2006-12-01

The quantification of fossil fuel CO2 emissions has implications for a wide variety of scientific and policy- related questions. Improvement in inverse-estimated carbon fluxes, country-level carbon budgeting, analysis of regional emissions trading systems, and targeting of observational systems are all important applications better served by improvements in understanding where and when fossil fuel/industrial CO2 is emitted. Traditional approaches to quantifying fossil/industrial CO2 emissions have relied on national sales/consumption of fossil fuels with secondary spatial footprints performed via proxies such as population. This approach has provided global spatiotemporal resolution of one degree/monthly. In recent years the need has arisen for emission estimates that not only achieve higher spatiotemporal scales but include a process- level component. This latter attribute provides dynamic linkages between energy policy/decisionmaking and emissions for use in projecting changes to energy systems and the implications these changes may have on climate change. We have embarked on a NASA-funded research strategy to construct a process-level fossil/industrial CO2 emissions model/database for North America that will resolve fossil/industrial CO2 emissions hourly and at 36 km. This project is a critical component of the North American Carbon Program. Our approach builds off of many decades of air quality monitoring for regulated pollutants such as NOx, VOCs and CO that has been performed by regional air quality managers, states, and the Environmental Protection Agency in the United States. By using the highly resolved monitoring data supplied to the EPA, we have computed CO2 emissions for residential, commercial/industrial, transportation, and biogenic sources. This effort employs a new emissions modeling system (CONCEPT) that spatially and temporally distributes the monitored emissions across the US. We will provide a description of the methodology we have employed, the difficulties encountered and some preliminary results. We will then compare our results to the traditional fossil/industrial CO2 emissions based on national sale/consumption statistics.

Using Geothermal Electric Power to Reduce Carbon Footprint

NASA Astrophysics Data System (ADS)

Crombie, George W.

Human activities, including the burning of fossil fuels, increase carbon dioxide levels, which contributes to global warming. The research problem of the current study examined if geothermal electric power could adequately replace fossil fuel by 2050, thus reducing the emissions of carbon dioxide while avoiding potential problems with expanding nuclear generation. The purpose of this experimental research was to explore under what funding and business conditions geothermal power could be exploited to replace fossil fuels, chiefly coal. Complex systems theory, along with network theory, provided the theoretical foundation for the study. Research hypotheses focused on parameters, such as funding level, exploration type, and interfaces with the existing power grid that will bring the United States closest to the goal of phasing out fossil based power by 2050. The research was conducted by means of computer simulations, using agent-based modeling, wherein data were generated and analyzed. The simulations incorporated key information about the location of geothermal resources, exploitation methods, transmission grid limits and enhancements, and demand centers and growth. The simulation suggested that rapid and aggressive deployment of geothermal power plants in high potential areas, combined with a phase out of coal and nuclear plants, would produce minimal disruptions in the supply of electrical power in the United States. The implications for social change include reduced risk of global warming for all humans on the planet, reduced pollution due to reduction or elimination of coal and nuclear power, increased stability in energy supply and prices in the United States, and increased employment of United States citizens in jobs related to domestic energy production.

Forest structure and downed woody debris in boreal temperate, and tropical forest fragments

Treesearch

William A. Gould; Grizelle Gonzalez; Andrew T. Hudak; Teresa Nettleton Hollingsworth; Jamie Hollingsworth

2008-01-01

Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve...

Reducing hazardous fuels on nonindustrial private forests: factors influencing landowner decisions

Treesearch

A. Paige Fischer

2011-01-01

In mixed-ownership landscapes, fuels conditions on private lands have implications for fire risk on public lands and vice versa. The success of efforts to mitigate fire risk depends on the extent, efficacy, and coordination of treatments on nearby ownerships. Understanding factors in forest owners' decisions to address the risk of wildland fire is therefore...

Policy Determination on Limiting Potential to Emit for Koch Refining Company's Clean Fuels Project

EPA Pesticide Factsheets

This document may be of assistance in applying the Title V air operating permit regulations. This document is part of the Title V Policy and Guidance Database available at www2.epa.gov/title-v-operating-permits/title-v-operating-permit-policy-and-guidance-document-index. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

Lightweight aircraft engines, the potential and problems for use of automotive fuels

NASA Technical Reports Server (NTRS)

Patterson, D. J.

1983-01-01

A comprehensive data research and analysis for evaluating the use of automotive fuels as a substitute for aviation grade fuel by piston-type general aviation aircraft engines is presented. Historically known problems and potential problems with fuels were reviewed for possible impact relative to application to an aircraft operational environment. This report reviews areas such as: fuel specification requirements, combustion knock, preignition, vapor lock, spark plug fouling, additives for fuel and oil, and storage stability.

Evaluation of the application of some gas chromatographic methods for the determination of properties of synthetic fuels

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1979-01-01

The purpose of the investigation was to evaluate the applicability, to some synthetic fuels, of some gas chromatographic methods now under development for use with petroleum based fuels. Thirty-two jet and diesel fuel samples which were prepared from oil shale and coal syncrudes were examined. The boiling range distribution of each was determined by gas chromatography, and from that data distillation properties were calculated. The calculated results gave sufficient agreement with the measured values that the equations could be useable in their present form. Bulk fuel properties were calculated for the sixteen JP-5 and Diesel No. 2 type fuels. The results show that the equations would not give useable results. Capillary column gas chromatography was used to determine the n-alkane content of the eight JP-5 type samples and the results related to the observed freezing points. The results show that the concentrations of the long straight chain molecules in the fuels exert influence on the freezing point but are not the complete controlling factor.

Evaluation of the application of some gas chromatographic methods for the determination of properties of synthetic fuels

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1978-01-01

The purpose of the investigation was to evaluate the applicability, to some synthetic fuels, of some gas chromatographic methods now under development for use with petroleum based fuels. Thirty-two jet and diesel fuel samples which were prepared from oil shale and coal syncrudes were examined. The boiling range distribution of each was determined by gas chromatography, and from that data distillation properties were calculated. The calculated results gave sufficient agreement with the measured values that the equations could be useable in their present form. Bulk fuel properties were calculated for the 16 JP-5 and Diesel No. 2 type fuels. The results show that the equations would not give useable results. Capillary column gas chromatography was used to determine the n-alkane content of the eight JP-5 type samples and the results related to the observed freezing points. The results show that the concentrations of the long straight chain molecules in the fuels exert influence on the freezing point but are not the complete controlling factor.

A comparison of producer gas, biochar, and activated carbon from two distributed scale thermochemical conversion systems used to process forest biomass

Treesearch

Nathaniel Anderson; J. Greg Jones; Deborah Page-Dumroese; Daniel McCollum; Stephen Baker; Daniel Loeffler; Woodam Chung

2013-01-01

Thermochemical biomass conversion systems have the potential to produce heat, power, fuels and other products from forest biomass at distributed scales that meet the needs of some forest industry facilities. However, many of these systems have not been deployed in this sector and the products they produce from forest biomass have not been adequately described or...

The Fukushima Dai-ichi Accident and its implications for the safety of nuclear power

NASA Astrophysics Data System (ADS)

Barletta, William

2016-05-01

Five years ago the dramatic events in Fukushima that followed the massive earthquake and subsequent tsunami that struck Japan on March 11, 2011 sharpened the focus of scientists, engineers and general public on the broad range of technical, environmental and societal issues involved in assuring the safety of the world's nuclear power complex. They also called into question the potential of nuclear power to provide a growing, sustainable resource of CO2-free energy. The issues raised by Fukushima Dai-ichi have provoked urgent concern, not only because of the potential harm that could result from severe accidents or from intentional damage to nuclear reactors or to facilities involved in the nuclear fuel cycle, but also because of the extensive economic impact of those accidents and of the measures taken to avoid them.

A Brief Literature Overview of Various Routes to Biorenewable Fuels from Lipids for the National Alliance for Advanced Biofuels and Bio-products (NAABB) Consortium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Albrecht, Karl O.; Hallen, Richard T.

2011-03-29

Renewable methods of producing transportation fuels are currently the focus of numerous large research efforts across the globe. Renewable fuel produced from algal lipids is one aspect of this research that could have profound implications on future transportation fuel requirements. However, technical challenges remain in several areas of algal-lipid-based fuels. These challenges include the identification and development of robust and productive algal species as well as extraction methods to recover the produced lipids. Not the least of these technical challenges is the conversion of the algae lipids to fungible fuels. This brief literature review focuses primarily on state-of-the-art “downstream” applicationsmore » of producing fuel from fats and lipids, which can be applied to ongoing research with algae-derived lipids.« less

Energy and population: transitional issues and eventual limits.

PubMed

Werbos, P J

1990-08-01

The implication of population size for US energy requirements is explored in this essay. The basic argument is that the present supply of fuels and energy technologies is not sustainable in the long run, that a wide range of choices is possible when a complete transition is made to sustainable technologies, and that the growth of population and the composition of this growth during the next 30 years are the most serious problems impacting on the achievement of sustainable technology. The importance and future of fuel oil is discussed as well as the transition to sustainable energy supplies: conservation, renewables, nuclear and coal. Dependency on oil can only be changed through time and the infusion of money, but even with these givens, the transition is also dependent on the political and budgetary climate. The race is between crisis and cure. It is argued that the soft energy systems (biomass, solar water heater, wind, hydro, and geothermal energy) along with conservation will increase easily and naturally, but the total potential from these sources amounts to only 10% of the present US energy supply. Conservation offers greater hope because 80% of end-use fossil fuel is used in transportation and industry. Further growth of the population in the US would create a demand to desalinate water, which would increase the demand for energy. A totally soft energy economy is probably not feasible without a drastic reduction in US population. The expected direction is in the increased use of coal, and then nuclear energy. Unfortunately, coal contributes to greenhouse warming, and the supply is limited to 60-100 years. Nuclear proliferation and terrorism is connected to the widespread use of nuclear energy. Some breakthrough technology with cold fusion may offer a safer alternative. High technology renewables such as solar cells can be competitive with nuclear energy, if prices can be kept down. on earth or in space, are being investigated. Exploring a variety of advanced technology is most likely to bring success. Therefore, government investment in accelerated research and development is necessary. The optimum population for the US would be 60 million people.

Costs and benefits of low-sulphur fuel standard for Baltic Sea shipping.

PubMed

Antturi, Jim; Hänninen, Otto; Jalkanen, Jukka-Pekka; Johansson, Lasse; Prank, Marje; Sofiev, Mikhail; Ollikainen, Markku

2016-12-15

The maximum allowable fuel sulphur content for shipping in the Baltic Sea dropped from 1%S to 0.1%S in 1 January 2015. We provide a cost-benefit analysis of the sulphur reduction policy in the Baltic Sea Sulphur Emission Control Area (SECA). We calculated the abatement costs based on shipowners' optimal decision-making in choosing between low-sulphur fuel and a sulphur scrubber, and the benefits were modelled through a high-resolution impact pathway analysis, which took into account the formation and dispersion of the emissions, and considered the positive health impacts resulting from lowered ambient PM 2.5 concentrations. Our basic result indicates that for the Baltic Sea only, the latest sulphur regulation is not cost-effective. The expected annual cost is roughly €465 M and benefit 2200 saved Disability Adjusted Life-Years (DALYs) or monetized €105 M. Based on our sensitivity analysis, the benefits yet have a potential to exceed the costs. The analysis neither takes into account the acidifying impact of sulphur nor the impact North Sea shipping has on the cost-benefit ratio. Lastly, a similar approach is found highly recommendable to study the implications of the upcoming Tier III NO x standard for shipping. Copyright © 2016 Elsevier Ltd. All rights reserved.

Greenhouse gas implications of a 32 billion gallon bioenergy landscape in the US

NASA Astrophysics Data System (ADS)

DeLucia, E. H.; Hudiburg, T. W.; Wang, W.; Khanna, M.; Long, S.; Dwivedi, P.; Parton, W. J.; Hartman, M. D.

2015-12-01

Sustainable bioenergy for transportation fuel and greenhouse gas (GHGs) reductions may require considerable changes in land use. Perennial grasses have been proposed because of their potential to yield substantial biomass on marginal lands without displacing food and reduce GHG emissions by storing soil carbon. Here, we implemented an integrated approach to planning bioenergy landscapes by combining spatially-explicit ecosystem and economic models to predict a least-cost land allocation for a 32 billion gallon (121 billion liter) renewable fuel mandate in the US. We find that 2022 GHG transportation emissions are decreased by 7% when 3.9 million hectares of eastern US land are converted to perennial grasses supplemented with corn residue to meet cellulosic ethanol requirements, largely because of gasoline displacement and soil carbon storage. If renewable fuel production is accompanied by a cellulosic biofuel tax credit, CO2 equivalent emissions could be reduced by 12%, because it induces more cellulosic biofuel and land under perennial grasses (10 million hectares) than under the mandate alone. While GHG reducing bioenergy landscapes that meet RFS requirements and do not displace food are possible, the reductions in GHG emissions are 50% less compared to previous estimates that did not account for economically feasible land allocation.

Oil shortages, climate change and collective action.

PubMed

Newbery, David

2011-05-13

Concerns over future oil scarcity might not be so worrying but for the high carbon content of substitutes, and the limited capacity of the atmosphere to absorb additional CO(2) from burning fuel. The paper argues that the tools of economics are helpful in understanding some of the key issues in pricing fossil fuels, the extent to which pricing can be left to markets, the need for, and design of, international agreements on corrective carbon pricing, and the potential Prisoners' Dilemma in reaching such agreements, partly mitigated in the case of oil by current taxes and the probable incidence of carbon taxes on the oil price. The 'Green Paradox', in which carbon pricing exacerbates climate change, is theoretically possible, but empirically unlikely. © 2011 Royal Society

Transportation Energy Futures Series: Vehicle Technology Deployment Pathways: An Examination of Timing and Investment Constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plotkin, S.; Stephens, T.; McManus, W.

2013-03-01

Scenarios of new vehicle technology deployment serve various purposes; some will seek to establish plausibility. This report proposes two reality checks for scenarios: (1) implications of manufacturing constraints on timing of vehicle deployment and (2) investment decisions required to bring new vehicle technologies to market. An estimated timeline of 12 to more than 22 years from initial market introduction to saturation is supported by historical examples and based on the product development process. Researchers also consider the series of investment decisions to develop and build the vehicles and their associated fueling infrastructure. A proposed decision tree analysis structure could bemore » used to systematically examine investors' decisions and the potential outcomes, including consideration of cash flow and return on investment. This method requires data or assumptions about capital cost, variable cost, revenue, timing, and probability of success/failure, and would result in a detailed consideration of the value proposition of large investments and long lead times. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency effort to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Transportation Energy Futures Series. Vehicle Technology Deployment Pathways. An Examination of Timing and Investment Constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plotkin, Steve; Stephens, Thomas; McManus, Walter

2013-03-01

Scenarios of new vehicle technology deployment serve various purposes; some will seek to establish plausibility. This report proposes two reality checks for scenarios: (1) implications of manufacturing constraints on timing of vehicle deployment and (2) investment decisions required to bring new vehicle technologies to market. An estimated timeline of 12 to more than 22 years from initial market introduction to saturation is supported by historical examples and based on the product development process. Researchers also consider the series of investment decisions to develop and build the vehicles and their associated fueling infrastructure. A proposed decision tree analysis structure could bemore » used to systematically examine investors' decisions and the potential outcomes, including consideration of cash flow and return on investment. This method requires data or assumptions about capital cost, variable cost, revenue, timing, and probability of success/failure, and would result in a detailed consideration of the value proposition of large investments and long lead times. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency effort to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Associating a prototypical forbidden food item with guilt or celebration: relationships with indicators of (un)healthy eating and the moderating role of stress and depressive symptoms.

PubMed

Kuijer, Roeline G; Boyce, Jessica A; Marshall, Emma M

2015-01-01

The increase in obesity and the many educational messages prompting us to eat a healthy diet have heightened people's concerns about the effects of food choice on health and weight. An unintended side effect may be that such awareness fuels feelings of guilt and worry about food. Although guilt has the potential to motivate behaviour change, it may also lead to feelings of helplessness and loss of control. The current study examined the relationship between a default association of either 'guilt' or 'celebration' with a prototypical forbidden food item (chocolate cake), indicators of healthy eating and choosing food for mood regulation reasons. Following a 'diathesis-stress' perspective, the moderating roles of depressive symptoms and stress were examined. Although a default association of guilt was found to be harmless under some circumstances (i.e. under low stress), those who associated chocolate cake with guilt (vs. celebration) reported unhealthier eating habits and lower levels of perceived behavioural control over healthy eating when under stress, rated mood regulation reasons for food choice as important irrespective of their current affective state, and did not have more positive attitudes towards healthy eating. Implications for public health messages and interventions will be discussed.

Energy Policy Act of 1992 : limited progress in acquiring alternative fuel vehicles and reaching fuel goals

DOT National Transportation Integrated Search

2000-02-01

Since the passage of the Energy Policy Act of 1992, some, albeit limited, progress has been made in acquiring alternative fuel vehicles and reducing the consumption of petroleum fuels in transportation. DOE estimates about 1 million alternative fuel ...

Conversion of wood residues to diesel fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuester, J.L.

1981-01-01

The basic approach is indirect liquefaction, i.e., thermal gasification followed by catalytic liquefaction. The indirect approach results in separation of the oxygen in the biomass feedstock, i.e., oxygenated compounds do not appear in the liquid hydrocarbon fuel product. The general conversion scheme is shown. The process is capable of accepting a wide variety of feedstocks. Potential products include medium quality gas, normal propanol, paraffinic fuel and/or high octane gasoline. A flow diagram of the continuous laboratory unit is shown. A fluidized bed pyrolysis system is used for gasification. Capacity is about 10 lbs/h of feedstock. The pyrolyzer can be fluidizedmore » with recycle pyrolysis gas, steam or recycle liquefaction system off gas or some combination thereof. Tars are removed in a wet scrubber. Unseparated pyrolysis gases are utilized as feed to a modified Fischer-Tropsch reactor. The liquid condensate from the reactor consists of a normal propanol-water phase and a paraffinic hydrocarbon phase. The reactor can be operated to optimize for either product. If a high octane gasoline is desired, the paraffinic fuel is passed through a conventional catalytic reformer. The normal propanol could be used as a fuel extender if blended with the hydrocarbon fuel products. Off gases from the downstream reactors are of high quality due to the accumulation of low molecular weight paraffins.« less

Producing liquid fuels from biomass

NASA Astrophysics Data System (ADS)

Solantausta, Yrjo; Gust, Steven

The aim of this survey was to compare, on techno-economic criteria, alternatives of producing liquid fuels from indigenous raw materials in Finland. Another aim was to compare methods under development and prepare a proposal for steering research related to this field. Process concepts were prepared for a number of alternatives, as well as analogous balances and production and investment cost assessments for these balances. Carbon dioxide emissions of the alternatives and the price of CO2 reduction were also studied. All the alternatives for producing liquid fuels from indigenous raw materials are utmost unprofitable. There are great differences between the alternatives. While the production cost of ethanol is 6 to 9 times higher than the market value of the product, the equivalent ratio for substitute fuel oil produced from peat by pyrolysis is 3 to 4. However, it should be borne in mind that the technical uncertainties related to the alternatives are of different magnitude. Production of ethanol from barley is of commercial technology, while biomass pyrolysis is still under development. If the aim is to reach smaller carbon dioxide emissions by using liquid biofuels, the most favorable alternative is pyrolysis oil produced from wood. Fuels produced from cultivated biomass are more expensive ways of reducing CO2 emissions. Their potential of reducing CO2 emissions in Finland is insignificant. Integration of liquid fuel production to some other production line is more profitable.

Structure of Laminar Permanently Blue, Opposed-Jet Ethylene-Fueled Diffusion Flames

NASA Technical Reports Server (NTRS)

Lin, K.-C.; Faeth, G. M.; Urban, D. L. (Technical Monitor)

2000-01-01

The structure and state relationships of laminar soot-free (permanently blue) ethylene-fueled diffusion flames at various strain rates were studied both experimentally and computationally using an opposed-jet configuration. Measurements of gas velocities, temperatures, and compositions were carried out along the stagnation stream line. Corresponding predictions of flame structure were obtained, based on numerical simulations using several contemporary reaction mechanisms for methane oxidation. Flame conditions studied included ethylene-fueled opposed-jet diffusion flames having stoichiometric mixture fractions of 0.7 with measurements involving strain rates of 60-240/s and predictions involving strain rates of 0-1140/s at normal temperature and pressure. It was found that measured major gas species concentrations and temperature distributions were in reasonably good agreement with predictions using mechanisms due to GRI-Mech and Peters and that effects of preferential diffusion significantly influence flame structure even when reactant mass diffusivities are similar. Oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures were found to exist over a broad range of strain rates, providing potential for significant computational simplifications for modeling purposes in some instances.

Structure of Laminar Permanently Blue, Opposed-Jet Ethylene-Fueled Diffusion Flames. Appendix E

NASA Technical Reports Server (NTRS)

Lin, K.-C.; Faeth, G. M.; Urban, D. L. (Technical Monitor)

2000-01-01

The structure and state relationships of laminar soot-free (permanently blue) ethylene-fueled diffusion flames at various strain rates were studied both experimentally and computationally using an opposed-jet configuration. Measurements of gas velocities, temperatures, and compositions were carried out along the stagnation stream line. Corresponding predictions of flame structure were obtained, based on numerical simulations using several contemporary reaction mechanisms for methane oxidation. Flame conditions studied included ethylene-fueled opposed-jet diffusion flames having stoichiometric mixture fractions of 0.7 with measurements involving strain rates of 60-240/s and predictions involving strain rates of 0-1140/s at normal temperature and pressure. It was found that measured major gas species concentrations and temperature distributions were in reasonably good agreement with predictions using mechanisms due to GRI-Mech and Peters and that effects of preferential diffusion significantly influence flame structure even when reactant mass diffusivities are similar. Oxygen leakage to fuel-rich conditions and carbon monoxide leakage to fuel-lean conditions both increased as strain rates increased. Furthermore, increased strain rates caused increased fuel concentrations near the flame sheet, decreased peak gas temperatures, and decreased concentrations of carbon dioxide and water vapor throughout the flames. State relationships for major gas species and gas temperatures were found to exist over a broad range of strain rates, providing potential for significant computational simplifications for modeling purposes in some instances.

Evaluation of Cetane Improver Additive in Alternative Jet Fuel Blends

DTIC Science & Technology

2016-07-01

diesel engines are sensitive to cetane values of fuel. Some fuels originating from nonpetroleum sources contain low cetane numbers that have trouble...Improver Additive, Diesel Fuel, JP-8, Kerosene, Aviation Fuel, Alternative Fuel 16. SECURITY CLASSIFICATION OF: a. REPORT ,,b. ABSTRACT r· THIS...performance of a diesel fuel oil obtained by comparing it to reference fuels in a standardized engine test (1). The cetane number has an inverse

Comment [on “Science in the political arena: Taking fire from the right and the left”

NASA Astrophysics Data System (ADS)

Darzi, Mike

The points made in “Science in the Political Arena: Taking Fire From the Right and the Left” [Eos, Nov. 21, 1995, p. 480] are well taken. However, I disagree strongly with the implication that assaults on science from the right and left are of equal gravity. While the assault from the left disrupts certain scientific projects, the assault from the right, I believe, risks America's preeminence in science and the development of significant benefits to society. Although environmentalists and animal-rights activists have certainly impeded research in some cases, their activism has also spurred many other fields of research including global change and biodiversity, and encouraged the development of fresh water supplies and alternative fuel sources.

Exploring the Relationship Between Octane Sensitivity and Heat-of-Vaporization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sluder, C. Scott; Szybist, James P.; McCormick, Robert L.

2016-04-05

The latent heat-of-vaporization (HoV) of blends of biofuel and hydrocarbon components into gasolines has recently experienced expanded interest because of the potential for increased HoV to increase fuel knock resistance in direct-injection (DI) engines. Several studies have been conducted, with some studies identifying an additional anti-knock benefit from HoV and others failing to arrive at the same conclusion. Consideration of these studies holistically shows that they can be grouped according to the level of fuel octane sensitivity variation within their fuel matrices. When comparing fuels of different octane sensitivity significant additional anti-knock benefits associated with HoV are sometimes observed. Studiesmore » that fix the octane sensitivity find that HoV does not produce additional anti-knock benefit. New studies were performed at ORNL and NREL to further investigate the relationship between HoV and octane sensitivity. Three fuels were formulated for the ORNL study with matched RON and octane sensitivity, but with differing HoV. Experiments with these fuels in a 1.6-liter GTDI engine showed that the fuels exhibited very similar combustion phasing under knock-limited spark advance (KLSA) conditions. Fuels having a range of RON, octane sensitivity, and HoV were tested at NREL in a single-cylinder GDI engine under conditions where octane sensitivity has little effect on knock resistance. KLSA was found to be well correlated with RON. These results reinforce the concept that HoV anti-knock effects can be viewed as a contributor to octane sensitivity. From this viewpoint, HoV effects manifest themselves as increases in octane sensitivity.« less

Reducing GHG emissions in the United States' transportation sector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sujit; Andress, David A; Nguyen, Tien

Reducing GHG emissions in the U.S. transportation sector requires both the use of highly efficient propulsion systems and low carbon fuels. This study compares reduction potentials that might be achieved in 2060 for several advanced options including biofuels, hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and fuel cell electric vehicles (FCEV), assuming that technical and cost reduction targets are met and necessary fueling infrastructures are built. The study quantifies the extent of the reductions that can be achieved through increasing engine efficiency and transitioning to low-carbon fuels separately. Decarbonizing the fuels is essential for achieving large reductions inmore » GHG emissions, and the study quantifies the reductions that can be achieved over a range of fuel carbon intensities. Although renewables will play a vital role, some combination of coal gasification with carbon capture and sequestration, and/or nuclear energy will likely be needed to enable very large reductions in carbon intensities for hydrogen and electricity. Biomass supply constraints do not allow major carbon emission reductions from biofuels alone; the value of biomass is that it can be combined with other solutions to help achieve significant results. Compared with gasoline, natural gas provides 20% reduction in GHG emissions in internal combustion engines and up to 50% reduction when used as a feedstock for producing hydrogen or electricity, making it a good transition fuel for electric propulsion drive trains. The material in this paper can be useful information to many other countries, including developing countries because of a common factor: the difficulty of finding sustainable, low-carbon, cost-competitive substitutes for petroleum fuels.« less

Fuel Characteristic Classification System version 3.0: technical documentation

Treesearch

Susan J. Prichard; David V. Sandberg; Roger D. Ottmar; Ellen Eberhardt; Anne Andreu; Paige Eagle; Kjell Swedin

2013-01-01

The Fuel Characteristic Classification System (FCCS) is a software module that records wildland fuel characteristics and calculates potential fire behavior and hazard potentials based on input environmental variables. The FCCS 3.0 is housed within the Integrated Fuels Treatment Decision Support System (Joint Fire Science Program 2012). It can also be run from command...

Characterizing crown fuel distribution for conifers in the interior western United States

Treesearch

Seth Ex; Frederick W. Smith; Tara Keyser

2015-01-01

Canopy fire hazard evaluation is essential for prioritizing fuel treatments and for assessing potential risk to firefighters during suppression activities. Fire hazard is usually expressed as predicted potential fire behavior, which is sensitive to the methodology used to quantitatively describe fuel profiles: methodologies that assume that fuel is distributed...

A comparison of hydrogen, methanol and gasoline as fuels for fuel cell vehicles: implications for vehicle design and infrastructure development

NASA Astrophysics Data System (ADS)

Ogden, Joan M.; Steinbugler, Margaret M.; Kreutz, Thomas G.

All fuel cells currently being developed for near term use in electric vehicles require hydrogen as a fuel. Hydrogen can be stored directly or produced onboard the vehicle by reforming methanol, or hydrocarbon fuels derived from crude oil (e.g., gasoline, diesel, or middle distillates). The vehicle design is simpler with direct hydrogen storage, but requires developing a more complex refueling infrastructure. In this paper, we present modeling results comparing three leading options for fuel storage onboard fuel cell vehicles: (a) compressed gas hydrogen storage, (b) onboard steam reforming of methanol, (c) onboard partial oxidation (POX) of hydrocarbon fuels derived from crude oil. We have developed a fuel cell vehicle model, including detailed models of onboard fuel processors. This allows us to compare the vehicle performance, fuel economy, weight, and cost for various vehicle parameters, fuel storage choices and driving cycles. The infrastructure requirements are also compared for gaseous hydrogen, methanol and gasoline, including the added costs of fuel production, storage, distribution and refueling stations. The delivered fuel cost, total lifecycle cost of transportation, and capital cost of infrastructure development are estimated for each alternative. Considering both vehicle and infrastructure issues, possible fuel strategies leading to the commercialization of fuel cell vehicles are discussed.

Nuclear energy and security

DOE Office of Scientific and Technical Information (OSTI.GOV)

BLEJWAS,THOMAS E.; SANDERS,THOMAS L.; EAGAN,ROBERT J.

2000-01-01

Nuclear power is an important and, the authors believe, essential component of a secure nuclear future. Although nuclear fuel cycles create materials that have some potential for use in nuclear weapons, with appropriate fuel cycles, nuclear power could reduce rather than increase real proliferation risk worldwide. Future fuel cycles could be designed to avoid plutonium production, generate minimal amounts of plutonium in proliferation-resistant amounts or configurations, and/or transparently and efficiently consume plutonium already created. Furthermore, a strong and viable US nuclear infrastructure, of which nuclear power is a large element, is essential if the US is to maintain a leadershipmore » or even participatory role in defining the global nuclear infrastructure and controlling the proliferation of nuclear weapons. By focusing on new fuel cycles and new reactor technologies, it is possible to advantageously burn and reduce nuclear materials that could be used for nuclear weapons rather than increase and/or dispose of these materials. Thus, the authors suggest that planners for a secure nuclear future use technology to design an ideal future. In this future, nuclear power creates large amounts of virtually atmospherically clean energy while significantly lowering the threat of proliferation through the thoughtful use, physical security, and agreed-upon transparency of nuclear materials. The authors must develop options for policy makers that bring them as close as practical to this ideal. Just as Atoms for Peace became the ideal for the first nuclear century, they see a potential nuclear future that contributes significantly to power for peace and prosperity.« less

Nuclear Energy Advanced Modeling and Simulation (NEAMS) Accident Tolerant Fuels High Impact Problem: Coordinate Multiscale FeCrAl Modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gamble, K. A.; Hales, J. D.; Zhang, Y.

Since the events at the Fukushima-Daiichi nuclear power plant in March 2011 significant research has unfolded at national laboratories, universities and other institutions into alternative materials that have potential enhanced ac- cident tolerance when compared to traditional UO2 fuel zircaloy clad fuel rods. One of the potential replacement claddings are iron-chromium-alunimum (FeCrAl) alloys due to their increased oxidation resistance [1–4] and higher strength [1, 2]. While the oxidation characteristics of FeCrAl are a benefit for accident tolerance, the thermal neu- tron absorption cross section of FeCrAl is about ten times that of Zircaloy. This neutronic penalty necessitates thinner cladding. Thismore » allows for slightly larger pellets to give the same cold gap width in the rod. However, the slight increase in pellet diameter is not sufficient to compensate for the neutronic penalty and enriching the fuel beyond the current 5% limit appears to be necessary [5]. Current estimates indicate that this neutronic penalty will impose an increase in fuel cost of 15-35% [1, 2]. In addition to the neutronic disadvantage, it is anticipated that tritium release to the coolant will be larger because the permeability of hydrogen in FeCrAl is about 100 times higher than in Zircaloy [6]. Also, radiation-induced hardening and embrittlement of FeCrAl need to be fully characterized experimentally [7]. Due to the aggressive development schedule for inserting some of the potential materials into lead test assemblies or rods by 2022 [8] multiscale multiphysics modeling approaches have been used to provide insight into these the use of FeCrAl as a cladding material. The purpose of this letter report is to highlight the multiscale modeling effort for iron-chromium-alunimum (FeCrAl) cladding alloys as part of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program through its Accident Tolerant Fuel (ATF) High Impact Problem (HIP). The approach taken throughout the HIP is to utilize lower length scale approaches (e.g., density functional theory, cluster dynamics, rate theory, phase field, and Visco-Plastic- Self-Consistent (VPSC)) to develop more physically informed models at the engineering scale for use in the BISON [9] fuel performance code.« less

Genetic Technology and Agricultural Development

ERIC Educational Resources Information Center

Staub, William J.; Blase, Melvin G.

1971-01-01

Examines the nature, application, limits and potential of applied genetics in plant breeding as a factor in South Asian agricultural development. Concludes other factors were also present in recent agricultural growth, and indicates some economic implications of continued growth, including problems of employment of displaced rural workers. (AL)

Analysis of Connected and Automated Vehicle Technologies Highlights

Science.gov Websites

Uncertainty in Potential Effects on Fuel Use, Miles Traveled | News | NREL Analysis of Connected and Automated Vehicle Technologies Highlights Uncertainty in Potential Effects on Fuel Use, Miles Potential Effects on Fuel Use, Miles Traveled December 13, 2016 A joint study from the U.S. Department of

Help or hindrance? The travel, energy and carbon impacts of highly automated vehicles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wadud, Zia; MacKenzie, Don; Leiby, Paul

In 5-10 years, experts predict that new automobiles will be capable of driving themselves under limited conditions and under most conditions within 10–20 years. Automation may affect road vehicle energy consumption and greenhouse gas (GHG) emissions in a host of ways, positive and negative, by causing changes in travel demand, vehicle design, vehicle operating profiles, and choices of fuels. In this paper, we identify specific mechanisms through which automation may affect travel and energy demand and resulting GHG emissions and bring them together using a coherent energy decomposition framework. Here, we review the literature for estimates of the energy impactsmore » of each mechanism and, where the literature is lacking, develop our own estimates using engineering and economic analysis. We consider how widely applicable each mechanism is, and quantify the potential impact of each mechanism on a common basis: the percentage change it is expected to cause in total GHG emissions from light-duty or heavy-duty vehicles in the U.S. Our primary focus is travel related energy consumption and emissions, since potential lifecycle impacts are generally smaller in magnitude. We also explore the net effects of automation on emissions through several illustrative scenarios, finding that automation might plausibly reduce road transport GHG emissions and energy use by nearly half – or nearly double them – depending on which effects come to dominate. We also find that many potential energy-reduction benefits may be realized through partial automation, while the major energy/emission downside risks appear more likely at full automation. Finally, we present some implications for policymakers and identifying priority areas for further research.« less

Help or hindrance? The travel, energy and carbon impacts of highly automated vehicles

DOE PAGES

Wadud, Zia; MacKenzie, Don; Leiby, Paul

2016-02-26

In 5-10 years, experts predict that new automobiles will be capable of driving themselves under limited conditions and under most conditions within 10–20 years. Automation may affect road vehicle energy consumption and greenhouse gas (GHG) emissions in a host of ways, positive and negative, by causing changes in travel demand, vehicle design, vehicle operating profiles, and choices of fuels. In this paper, we identify specific mechanisms through which automation may affect travel and energy demand and resulting GHG emissions and bring them together using a coherent energy decomposition framework. Here, we review the literature for estimates of the energy impactsmore » of each mechanism and, where the literature is lacking, develop our own estimates using engineering and economic analysis. We consider how widely applicable each mechanism is, and quantify the potential impact of each mechanism on a common basis: the percentage change it is expected to cause in total GHG emissions from light-duty or heavy-duty vehicles in the U.S. Our primary focus is travel related energy consumption and emissions, since potential lifecycle impacts are generally smaller in magnitude. We also explore the net effects of automation on emissions through several illustrative scenarios, finding that automation might plausibly reduce road transport GHG emissions and energy use by nearly half – or nearly double them – depending on which effects come to dominate. We also find that many potential energy-reduction benefits may be realized through partial automation, while the major energy/emission downside risks appear more likely at full automation. Finally, we present some implications for policymakers and identifying priority areas for further research.« less

Steam Methane Reformation Testing for Air-Independent Solid Oxide Fuel Cell Systems

NASA Technical Reports Server (NTRS)

Mwara, Kamwana N.

2015-01-01

Recently, NASA has been looking into utilizing landers that can be propelled by LOX-CH (sub 4), to be used for long duration missions. Using landers that utilize such propellants, also provides the opportunity to use solid oxide fuel cells as a power option, especially since they are able to process methane into a reactant through fuel reformation. One type of reformation, called steam methane reformation, is a process to reform methane into a hydrogen-rich product by reacting methane and steam (fuel cell exhaust) over a catalyst. A steam methane reformation system could potentially use the fuel cell's own exhaust to create a reactant stream that is hydrogen-rich, and requires less internal reforming of the incoming methane. Also, steam reformation may hold some advantages over other types of reforming, such as partial oxidation (PROX) reformation. Steam reformation does not require oxygen, while up to 25 percent can be lost in PROX reformation due to unusable CO (sub 2) reformation. NASA's Johnson Space Center has conducted various phases of steam methane reformation testing, as a viable solution for in-space reformation. This has included using two different types of catalysts, developing a custom reformer, and optimizing the test system to find the optimal performance parameters and operating conditions.

Identification of two distinct fire regimes in Southern California: implications for economic impact and future change

Treesearch

Yufang Jin; Michael L. Goulden; Nicolas Faivre; Sander Veraverbeke; Fengpeng Sun; Alex Hall; Michael S. Hand; Simon Hook; James T. Randerson

2015-01-01

The area burned by Southern California wildfires has increased in recent decades, with implications for human health, infrastructure, and ecosystem management. Meteorology and fuel structure are universally recognized controllers of wildfire, but their relative importance, and hence the efficacy of abatement and suppression efforts, remains controversial....

Comparison of Vehicle-Broadcasted Fuel Consumption Rates against Precise Fuel Measurements for Medium- and Heavy-Duty Vehicles and Engines

DOE PAGES

Pink, Alex; Ragatz, Adam; Wang, Lijuan; ...

2017-03-28

Vehicles continuously report real-time fuel consumption estimates over their data bus, known as the controller area network (CAN). However, the accuracy of these fueling estimates is uncertain to researchers who collect these data from any given vehicle. To assess the accuracy of these estimates, CAN-reported fuel consumption data are compared against fuel measurements from precise instrumentation. The data analyzed consisted of eight medium/heavy-duty vehicles and two medium-duty engines. Varying discrepancies between CAN fueling rates and the more accurate measurements emerged but without a vehicular trend-for some vehicles the CAN under-reported fuel consumption and for others the CAN over-reported fuel consumption.more » Furthermore, a qualitative real-time analysis revealed that the operating conditions under which these fueling discrepancies arose varied among vehicles. A drive cycle analysis revealed that while CAN fueling estimate accuracy differs for individual vehicles, that CAN estimates capture the relative fuel consumption differences between drive cycles within 4% for all vehicles and even more accurately for some vehicles. Furthermore, in situations where only CAN-reported data are available, CAN fueling estimates can provide relative fuel consumption trends but not accurate or precise fuel consumption rates.« less

Comparison of Vehicle-Broadcasted Fuel Consumption Rates against Precise Fuel Measurements for Medium- and Heavy-Duty Vehicles and Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pink, Alex; Ragatz, Adam; Wang, Lijuan

Vehicles continuously report real-time fuel consumption estimates over their data bus, known as the controller area network (CAN). However, the accuracy of these fueling estimates is uncertain to researchers who collect these data from any given vehicle. To assess the accuracy of these estimates, CAN-reported fuel consumption data are compared against fuel measurements from precise instrumentation. The data analyzed consisted of eight medium/heavy-duty vehicles and two medium-duty engines. Varying discrepancies between CAN fueling rates and the more accurate measurements emerged but without a vehicular trend-for some vehicles the CAN under-reported fuel consumption and for others the CAN over-reported fuel consumption.more » Furthermore, a qualitative real-time analysis revealed that the operating conditions under which these fueling discrepancies arose varied among vehicles. A drive cycle analysis revealed that while CAN fueling estimate accuracy differs for individual vehicles, that CAN estimates capture the relative fuel consumption differences between drive cycles within 4% for all vehicles and even more accurately for some vehicles. Furthermore, in situations where only CAN-reported data are available, CAN fueling estimates can provide relative fuel consumption trends but not accurate or precise fuel consumption rates.« less

Applications of high pressure differential scanning calorimetry to aviation fuel thermal stability research

NASA Technical Reports Server (NTRS)

Neveu, M. C.; Stocker, D. P.

1985-01-01

High pressure differential scanning calorimetry (DSC) was studied as an alternate method for performing high temperature fuel thermal stability research. The DSC was used to measure the heat of reaction versus temperature of a fuel sample heated at a programmed rate in an oxygen pressurized cell. Pure hydrocarbons and model fuels were studied using typical DSC operating conditions of 600 psig of oxygen and a temperature range from ambient to 500 C. The DSC oxidation onset temperature was determined and was used to rate the fuels on thermal stability. Kinetic rate constants were determined for the global initial oxidation reaction. Fuel deposit formation is measured, and the high temperature volatility of some tetralin deposits is studied by thermogravimetric analysis. Gas chromatography and mass spectrometry are used to study the chemical composition of some DSC stressed fuels.

The Ethanol Project: Exploring Alternative Energy with Role-Play and Writing

ERIC Educational Resources Information Center

Winter, Julia

2013-01-01

This article describes a project that includes a two-week series of researching, essay writing, and speaking lessons exploring the broader implications of using ethanol as a fuel. The author, a chemistry teacher, describes how she uses a senate hearing discussion of ethanol fuel subsidies as the forum for a role-play. The four components of the…

Emissions from prescribed fire in temperate forest in south-east Australia: implications for carbon accounting

NASA Astrophysics Data System (ADS)

Possell, M.; Jenkins, M.; Bell, T. L.; Adams, M. A.

2014-09-01

We estimated of emissions of carbon, as CO2-equivalents, from planned fire in four sites in a south-eastern Australian forest. Emission estimates were calculated using measurements of fuel load and carbon content of different fuel types, before and after burning, and determination of fuel-specific emission factors. Median estimates of emissions for the four sites ranged from 20 to 139 T CO2-e ha-1. Variability in estimates was a consequence of different burning efficiencies of each fuel type from the four sites. Higher emissions resulted from more fine fuel (twigs, decomposing matter, near-surface live and leaf litter) or coarse woody debris (CWD; > 25 mm diameter) being consumed. In order to assess the effect of estimating emissions when only a few fuel variables are known, Monte-Carlo simulations were used to create seven scenarios where input parameters values were replaced by probability density functions. Calculation methods were: (1) all measured data were constrained between measured maximum and minimum values for each variable, (2) as for (1) except the proportion of carbon within a fuel type was constrained between 0 and 1, (3) as for (2) but losses of mass caused by fire were replaced with burning efficiency factors constrained between 0 and 1; and (4) emissions were calculated using default values in the Australian National Greenhouse Accounts (NGA), National Inventory Report 2011, as appropriate for our sites. Effects of including CWD in calculations were assessed for calculation Method 1, 2 and 3 but not for Method 4 as the NGA does not consider this fuel type. Simulations demonstrate that the probability of estimating true median emissions declines strongly as the amount of information available declines. Including CWD in scenarios increased uncertainty in calculations because CWD is the most variable contributor to fuel load. Inclusion of CWD in scenarios generally increased the amount of carbon lost. We discuss implications of these simulations and how emissions from prescribed burns in temperate Australian forests could be improved.

Ceramic applications in the advanced Stirling automotive engine

NASA Technical Reports Server (NTRS)

Tomazic, W. A.; Cairelli, J. E.

1977-01-01

The ideal cycle, its application to a practical machine, and the specific advantages of high efficiency, low emissions, multi-fuel capability, and low noise of the stirling engine are discussed. Certain portions of the Stirling engine must operate continuously at high temperature. Ceramics offer the potential of cost reduction and efficiency improvement for advanced engine applications. Potential applications for ceramics in Stirling engines, and some of the special problems pertinent to using ceramics in the Stirling engine are described. The research and technology program in ceramics which is planned to support the development of advanced Stirling engines is outlined.

A Multi-Methods Approach to HRA and Human Performance Modeling: A Field Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacques Hugo; David I Gertman

2012-06-01

The Advanced Test Reactor (ATR) is a research reactor at the Idaho National Laboratory is primarily designed and used to test materials to be used in other, larger-scale and prototype reactors. The reactor offers various specialized systems and allows certain experiments to be run at their own temperature and pressure. The ATR Canal temporarily stores completed experiments and used fuel. It also has facilities to conduct underwater operations such as experiment examination or removal. In reviewing the ATR safety basis, a number of concerns were identified involving the ATR canal. A brief study identified ergonomic issues involving the manual handlingmore » of fuel elements in the canal that may increase the probability of human error and possible unwanted acute physical outcomes to the operator. In response to this concern, that refined the previous HRA scoping analysis by determining the probability of the inadvertent exposure of a fuel element to the air during fuel movement and inspection was conducted. The HRA analysis employed the SPAR-H method and was supplemented by information gained from a detailed analysis of the fuel inspection and transfer tasks. This latter analysis included ergonomics, work cycles, task duration, and workload imposed by tool and workplace characteristics, personal protective clothing, and operational practices that have the potential to increase physical and mental workload. Part of this analysis consisted of NASA-TLX analyses, combined with operational sequence analysis, computational human performance analysis (CHPA), and 3D graphical modeling to determine task failures and precursors to such failures that have safety implications. Experience in applying multiple analysis techniques in support of HRA methods is discussed.« less

Hydrocarbon bio-jet fuel from bioconversion of poplar biomass: life cycle assessment.

PubMed

Budsberg, Erik; Crawford, Jordan T; Morgan, Hannah; Chin, Wei Shan; Bura, Renata; Gustafson, Rick

2016-01-01

Bio-jet fuels compatible with current aviation infrastructure are needed as an alternative to petroleum-based jet fuel to lower greenhouse gas emissions and reduce dependence on fossil fuels. Cradle to grave life cycle analysis is used to investigate the global warming potential and fossil fuel use of converting poplar biomass to drop-in bio-jet fuel via a novel bioconversion platform. Unique to the biorefinery designs in this research is an acetogen fermentation step. Following dilute acid pretreatment and enzymatic hydrolysis, poplar biomass is fermented to acetic acid and then distilled, hydroprocessed, and oligomerized to jet fuel. Natural gas steam reforming and lignin gasification are proposed to meet hydrogen demands at the biorefineries. Separate well to wake simulations are performed using the hydrogen production processes to obtain life cycle data. Both biorefinery designs are assessed using natural gas and hog fuel to meet excess heat demands. Global warming potential of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from CO2 equivalences of 60 to 66 and 32 to 73 g MJ(-1), respectively. Fossil fuel usage of the natural gas steam reforming and lignin gasification bio-jet fuel scenarios range from 0.78 to 0.84 and 0.71 to 1.0 MJ MJ(-1), respectively. Lower values for each impact category result from using hog fuel to meet excess heat/steam demands. Higher values result from using natural gas to meet the excess heat demands. Bio-jet fuels produced from the bioconversion of poplar biomass reduce the global warming potential and fossil fuel use compared with petroleum-based jet fuel. Production of hydrogen is identified as a major source of greenhouse gas emissions and fossil fuel use in both the natural gas steam reforming and lignin gasification bio-jet simulations. Using hog fuel instead of natural gas to meet heat demands can help lower the global warming potential and fossil fuel use at the biorefineries.

Working Memory Underpins Cognitive Development, Learning, and Education

PubMed Central

Cowan, Nelson

2014-01-01

Working memory is the retention of a small amount of information in a readily accessible form. It facilitates planning, comprehension, reasoning, and problem-solving. I examine the historical roots and conceptual development of the concept and the theoretical and practical implications of current debates about working memory mechanisms. Then I explore the nature of cognitive developmental improvements in working memory, the role of working memory in learning, and some potential implications of working memory and its development for the education of children and adults. The use of working memory is quite ubiquitous in human thought, but the best way to improve education using what we know about working memory is still controversial. I hope to provide some directions for research and educational practice. PMID:25346585

Effects of water-emulsified fuel on a diesel engine generator's thermal efficiency and exhaust.

PubMed

Syu, Jin-Yuan; Chang, Yuan-Yi; Tseng, Chao-Heng; Yan, Yeou-Lih; Chang, Yu-Min; Chen, Chih-Chieh; Lin, Wen-Yinn

2014-08-01

Water-emulsified diesel has proven itself as a technically sufficient improvement fuel to improve diesel engine fuel combustion emissions and engine performance. However, it has seldom been used in light-duty diesel engines. Therefore, this paper focuses on an investigation into the thermal efficiency and pollution emission analysis of a light-duty diesel engine generator fueled with different water content emulsified diesel fuels (WD, including WD-0, WD-5, WD-10, and WD-15). In this study, nitric oxide, carbon monoxide, hydrocarbons, and carbon dioxide were analyzed by a vehicle emission gas analyzer and the particle size and number concentration were measured by an electrical low-pressure impactor. In addition, engine loading and fuel consumption were also measured to calculate the thermal efficiency. Measurement results suggested that water-emulsified diesel was useful to improve the thermal efficiency and the exhaust emission of a diesel engine. Obviously, the thermal efficiency was increased about 1.2 to 19.9%. In addition, water-emulsified diesel leads to a significant reduction of nitric oxide emission (less by about 18.3 to 45.4%). However the particle number concentration emission might be increased if the loading of the generator becomes lower than or equal to 1800 W. In addition, exhaust particle size distributions were shifted toward larger particles at high loading. The consequence of this research proposed that the water-emulsified diesel was useful to improve the engine performance and some of exhaust emissions, especially the NO emission reduction. Implications: The accumulated test results provide a good basis to resolve the corresponding pollutants emitted from a light-duty diesel engine generator. By measuring and analyzing transforms of exhaust pollutant from this engine generator, the effects of water-emulsified diesel fuel and loading on emission characteristics might be more clear. Understanding reduction of pollutant emissions during the use of water-emulsified diesel helps improve the effectiveness of the testing program. The analyzed consequences provide useful information to the government for setting policies to curb pollutant emissions from a light-duty diesel engine generator more effectively.

Heat treatment induced bacterial changes in irrigation water and their implications for plant disease management.

PubMed

Hao, W; Hong, C X

2014-05-01

A new heat treatment for recycled irrigation water using 48 °C for 24 h to inactivate Phytophthora and bacterial plant pathogens is estimated to reduce fuel cost and environmental footprint by more than 50 % compared to current protocol (95 °C for 30 s). The objective of this study was to determine the impact of this new heat treatment temperature regime on bacterial community structure in water and its practical implications. Bacterial communities in irrigation water were analyzed before and after heat treatment using both culture-dependent and -independent strategies based on the 16S ribosomal DNA. A significant shift was observed in the bacterial community after heat treatment. Most importantly, bacteria with biological control potential--Bacillus and Paenibacillus, and Pseudomonas species became more abundant at both 48 and 42 °C. These findings imply that the new heat treatment procedure not only controls existing plant pathogens but also may make the heat-treated irrigation water a more antagonistic environment against plant pathogens, promoting sustainable disease management.

Global energy, sustainability, and the conventional development paradigm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raskin, P.D.; Margolis, R.M.

1998-05-01

The conventional development paradigm assumes that the values, consumption patterns, and dynamics of the western industrial system will be progressively played out on a global scale. In this inquiry, the authors explore the implications of the conventional paradigm for the evolution of global energy patterns, and the compatibility with notions of sustainability. They present a global long-range conventional development scenario to the year 2050, and identify major environmental, resource, and social pressures and uncertainties. These include the economic and geopolitical consequences of fossil fuel depletion, the environmental and security implications of increased nuclear generation, the risk of significant climatic change,more » and the threats to social cohesion of distributional inequities. Such potential problems could negate the basic scenario assumption of steady economic and social development. By clarifying the stress points in a conventional picture of energy development, the scenario provides a useful point of departure for examining alternative long-range scenarios for sustainable energy development.« less

Radioactive Waste Management, its Global Implication on Societies, and Political Impact

NASA Astrophysics Data System (ADS)

Matsui, Kazuaki

2009-05-01

Reprocessing plant in Rokkasho, Japan is under commissioning at the end of 2008, and it starts soon to reprocess about 800 Mt of spent fuel per annum, which have been stored at each nuclear power plant sites in Japan. Fission products together with minor actinides separated from uranium and plutonium in the spent fuel contain almost all radioactivity of it and will be vitrified with glass matrix, which then will fill the canisters. The canisters with the high level radioactive waste (HLW) are so hot in both thermal and radiological meanings that they have to be cooled off for decades before bringing out to any destination. Where is the final destination for HLW in Japan, which is located at the rim of the Pacific Ocean with volcanoes? Although geological formation in Japan is not so static and rather active as the other parts of the planet, experts concluded with some intensive studies and researches that there will be a lot of variety of geological formations even in Japan which can host the HLW for so long times of more than million years. Then an organization to implement HLW disposal program was set up and started to campaign for volunteers to accept the survey on geological suitability for HLW disposal. Some local governments wanted to apply, but were crashed down by local and neighbor governments and residents. The above development is not peculiar only to Japan, but generally speaking more or less common for those with radioactive waste programs. This is why the radioactive waste management is not any more science and technology issue but socio-political one. It does not mean further R&D on geological disposal is not any more necessary, but rather we, each of us, should face much more sincerely the societal and political issues caused by the development of the science and technology. Second topic might be how effective partitioning and transformation technology may be to reduce the burden of waste disposal and denature the waste toxicity? The third one might be the proposal of international nuclear fuel centers which supply nuclear fuel to the nuclear power plants in the region and take back spent fuel which will be reprocessed to recover useful energy resources of uranium and plutonium. This may help non proliferation issue due to world nuclear development beyond renaissance.

Toxicity evaluation of 2-hydroxybiphenyl and other compounds involved in studies of fossil fuels biodesulphurisation.

PubMed

Alves, L; Paixão, S M

2011-10-01

The acute toxicity of some compounds used in fossil fuels biodesulphurisation studies, on the respiration activity, was evaluated by Gordonia alkanivorans and Rhodococcus erythropolis. Moreover, the effect of 2-hydroxybiphenyl on cell growth of both strains was also determined, using batch (chronic bioassays) and continuous cultures. The IC₅₀ values obtained showed the toxicity of all the compounds tested to both strains, specially the high toxicity of 2-HBP. These results were confirmed by the chronic toxicity data. The toxicity data sets highlight for a higher sensitivity to the toxicant by the strain presenting a lower growth rate, due to a lower cells number in contact with the toxicant. Thus, microorganisms exhibiting faster generation times could be more resistant to 2-HBP accumulation during a BDS process. The physiological response of both strains to 2-HBP pulse in a steady-state continuous culture shows their potential to be used in a future fossil fuel BDS process. Copyright © 2011 Elsevier Ltd. All rights reserved.

Innovative technologies on fuel assemblies cleaning for sodium fast reactors: First considerations on cleaning process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simon, N.; Lorcet, H.; Beauchamp, F.

2012-07-01

Within the framework of Sodium Fast Reactor development, innovative fuel assembly cleaning operations are investigated to meet the GEN IV goals of safety and of process development. One of the challenges is to mitigate the Sodium Water Reaction currently used in these processes. The potential applications of aqueous solutions of mineral salts (including the possibility of using redox chemical reactions) to mitigate the Sodium Water Reaction are considered in a first part and a new experimental bench, dedicated to this study, is described. Anhydrous alternative options based on Na/CO{sub 2} interaction are also presented. Then, in a second part, amore » functional study conducted on the cleaning pit is proposed. Based on experimental feedback, some calculations are carried out to estimate the sodium inventory on the fuel elements, and physical methods like hot inert gas sweeping to reduce this inventory are also presented. Finally, the implementation of these innovative solutions in cleaning pits is studied in regard to the expected performances. (authors)« less

Projected Salt Waste Production from a Commercial Pyroprocessing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, Michael F.

Pyroprocessing of used nuclear fuel inevitably produces salt waste from electrorefining and/or oxide reduction unit operations. Various process design characteristics can affect the actual mass of such waste produced. This paper examines both oxide and metal fuel treatment, estimates the amount of salt waste generated, and assesses potential benefit of process options to mitigate the generation of salt waste. For reference purposes, a facility is considered in which 100 MT/year of fuel is processed. Salt waste estimates range from 8 to 20 MT/year from considering numerous scenarios. It appears that some benefit may be derived from advanced processes for separatingmore » fission products from molten salt waste, but the degree of improvement is limited. Waste form production is also considered but appears to be economically unfavorable. Direct disposal of salt into a salt basin type repository is found to be the most promising with respect to minimizing the impact of waste generation on the economic feasibility and sustainability of pyroprocessing.« less

Corrosion testing of candidates for the alkaline fuel cell cathode

NASA Technical Reports Server (NTRS)

Singer, Joseph; Fielder, William L.

1989-01-01

Current/voltage data was obtained for specially made corrosion electrodes of some oxides and of gold materials for the purpose of developing a screening test of catalysts and supports for use at the cathode of the alkaline fuel cell. The data consists of measurements of current at fixed potentials and cyclic voltammograms. These data will have to be correlated with longtime performance data in order to fully evaluate this approach to corrosion screening. Corrosion test screening of candidates for the oxygen reduction electrode of the alkaline fuel cell was applied to two substances, the pyrochlore Pb2Ru2O6.5 and the spinel NiCo2O4. The substrate gold screen and a sample of the IFC Orbiter Pt-Au performance electrode were included as blanks. The pyrochlore data indicate relative stability, although nothing yet can be said about long term stability. The spinel was plainly unstable. For this type of testing to be validated, comparisons will have to be made with long term performance tests.

The Neurobiology of "Food Addiction" and Its Implications for Obesity Treatment and Policy.

PubMed

Carter, Adrian; Hendrikse, Joshua; Lee, Natalia; Yücel, Murat; Verdejo-Garcia, Antonio; Andrews, Zane B.; Hall, Wayne

2016-07-17

There is a growing view that certain foods, particularly those high in refined sugars and fats, are addictive and that some forms of obesity can usefully be treated as a food addiction. This perspective is supported by a growing body of neuroscience research demonstrating that the chronic consumption of energy-dense foods causes changes in the brain's reward pathway that are central to the development and maintenance of drug addiction. Obese and overweight individuals also display patterns of eating behavior that resemble the ways in which addicted individuals consume drugs. We critically review the evidence that some forms of obesity or overeating could be considered a food addiction and argue that the use of food addiction as a diagnostic category is premature. We also examine some of the potential positive and negative clinical, social, and public policy implications of describing obesity as a food addiction that require further investigation.

Controversies in gestational diabetes.

PubMed

Nolan, Christopher J

2011-02-01

Gestational diabetes mellitus (GDM) and controversy are old friends. However, several major studies in the field have clarified some of the main issues. There is now no doubt that hyperglycaemia, at levels less than those that occur in overt diabetes, is associated with adverse pregnancy outcomes, such as large-for-gestational age infants, neonatal hyperinsulinism, neonatal hypoglycaemia and pre-eclampsia. We also have evidence now that a standard approach to GDM with diagnosis at 24-28 weeks, dietary advice, self-monitoring of blood glucose and insulin therapy as needed reduces these adverse perinatal outcomes. Unknown, however, is if this same approach is effective at reducing long-term risks of metabolic syndrome, type 2 diabetes and cardiovascular disease in both the mothers and babies. For example, could our management strategies miss critical time points of fuel-mediated injury to the foetus important for the baby's long-term metabolic health? The implications of a recent international consensus statement on new diagnostic criteria for GDM are discussed, as well as issues relating to the timing of diagnosis. The potential place for a risk calculator for adverse outcomes in GDM pregnancy that takes into account glycaemic and non-glycaemic risk factors is considered. Such a tool could help stratify GDM women to different levels of care. Ongoing issues relating to maternal glycaemic and foetal growth targets, and the use of oral hypoglycaemic agents in GDM are discussed. To resolve some of the remaining controversies, further carefully designed randomised controlled trials in GDM with long-term follow-up of both mothers and babies are necessary. Copyright © 2010 Elsevier Ltd. All rights reserved.

Information for Consumers about Alternative Fuel Conversions

EPA Pesticide Factsheets

Here are some factors to be aware of if you are considering fuel conversion, including background information on fuel conversion, instructions for demonstrating compliance, and other related information.

Estimates of CO2 from fires in the United States: implications for carbon management.

PubMed

Wiedinmyer, Christine; Neff, Jason C

2007-11-01

Fires emit significant amounts of CO2 to the atmosphere. These emissions, however, are highly variable in both space and time. Additionally, CO2 emissions estimates from fires are very uncertain. The combination of high spatial and temporal variability and substantial uncertainty associated with fire CO2 emissions can be problematic to efforts to develop remote sensing, monitoring, and inverse modeling techniques to quantify carbon fluxes at the continental scale. Policy and carbon management decisions based on atmospheric sampling/modeling techniques must account for the impact of fire CO2 emissions; a task that may prove very difficult for the foreseeable future. This paper addresses the variability of CO2 emissions from fires across the US, how these emissions compare to anthropogenic emissions of CO2 and Net Primary Productivity, and the potential implications for monitoring programs and policy development. Average annual CO2 emissions from fires in the lower 48 (LOWER48) states from 2002-2006 are estimated to be 213 (+/- 50 std. dev.) Tg CO2 yr-1 and 80 (+/- 89 std. dev.) Tg CO2 yr-1 in Alaska. These estimates have significant interannual and spatial variability. Needleleaf forests in the Southeastern US and the Western US are the dominant source regions for US fire CO2 emissions. Very high emission years typically coincide with droughts, and climatic variability is a major driver of the high interannual and spatial variation in fire emissions. The amount of CO2 emitted from fires in the US is equivalent to 4-6% of anthropogenic emissions at the continental scale and, at the state-level, fire emissions of CO2 can, in some cases, exceed annual emissions of CO2 from fossil fuel usage. The CO2 released from fires, overall, is a small fraction of the estimated average annual Net Primary Productivity and, unlike fossil fuel CO2 emissions, the pulsed emissions of CO2 during fires are partially counterbalanced by uptake of CO2 by regrowing vegetation in the decades following fire. Changes in fire severity and frequency can, however, lead to net changes in atmospheric CO2 and the short-term impacts of fire emissions on monitoring, modeling, and carbon management policy are substantial.

Topics in Finance Part III--Leverage

ERIC Educational Resources Information Center

Laux, Judy

2010-01-01

This article investigates operating and financial leverage from the perspective of the financial manager, accenting the relationships to stockholder wealth maximization (SWM), risk and return, and potential agency problems. It also covers some of the pertinent literature related specifically to the implications of operating and financial risk and…

Modeling some long-term implications of CO2 fertilization for global forests and forest industries

Treesearch

Joseph Buongiorno

2015-01-01

Background: This paper explored the long-term, ceteris-paribus effects of potential CO2 fertilization on the globalforest sector. Based on the findings of Norby et al. (PNAS 2005, 102(50)) about forest response to elevated [CO2].Methods:...

Commentary: Ubiquitous Computing Revisited--A New Perspective

ERIC Educational Resources Information Center

Bull, Glen; Garofalo, Joe

2006-01-01

In 2002, representatives from the teacher educator associations representing the core content areas (science, mathematics, language arts, and social studies) and educational technology met at the National Technology Leadership Retreat (NTLR) to discuss potential implications of ubiquitous computing for K-12 schools. This paper re-examines some of…

General medicine and surgery for dental practitioners. Part 5--Psychiatry.

PubMed

Brown, S; Greenwood, M; Meechan, J G

2010-07-10

There are a significant number of patients in society who have some form of psychiatric disorder. It is important that dental practitioners have an awareness of the more common psychiatric disorders and their potential implications as they are likely to encounter them in clinical practice.

Final Summary Report on Project 3310 Marine Diesel Exhaust Emissions (Alternative Fuels)

DTIC Science & Technology

1997-09-01

of five types) operating on the West Coast. Of the 14 vessels tested, eight were found to exceed the proposed NOx limits, although some by very small amounts....develop methodology applicable for use on small vessels by using portable emission analyzers, and to examine various potential means of reducing excessive...This report summarizes the results of a 5-year study to ascertain the magnitude of emission problems from Coast Guard and

Unsupervised classification of petroleum Certified Reference Materials and other fuels by chemometric analysis of gas chromatography-mass spectrometry data

PubMed Central

de Carvalho Rocha, Werickson Fortunato; Schantz, Michele M.; Sheen, David A.; Chu, Pamela M.; Lippa, Katrice A.

2017-01-01

As feedstocks transition from conventional oil to unconventional petroleum sources and biomass, it will be necessary to determine whether a particular fuel or fuel blend is suitable for use in engines. Certifying a fuel as safe for use is time-consuming and expensive and must be performed for each new fuel. In principle, suitability of a fuel should be completely determined by its chemical composition. This composition can be probed through use of detailed analytical techniques such as gas chromatography-mass spectroscopy (GC-MS). In traditional analysis, chromatograms would be used to determine the details of the composition. In the approach taken in this paper, the chromatogram is assumed to be entirely representative of the composition of a fuel, and is used directly as the input to an algorithm in order to develop a model that is predictive of a fuel's suitability. When a new fuel is proposed for service, its suitability for any application could then be ascertained by using this model to compare its chromatogram with those of the fuels already known to be suitable for that application. In this paper, we lay the mathematical and informatics groundwork for a predictive model of hydrocarbon properties. The objective of this work was to develop a reliable model for unsupervised classification of the hydrocarbons as a prelude to developing a predictive model of their engine-relevant physical and chemical properties. A set of hydrocarbons including biodiesel fuels, gasoline, highway and marine diesel fuels, and crude oils was collected and GC-MS profiles obtained. These profiles were then analyzed using multi-way principal components analysis (MPCA), principal factors analysis (PARAFAC), and a self-organizing map (SOM), which is a kind of artificial neural network. It was found that, while MPCA and PARAFAC were able to recover descriptive models of the fuels, their linear nature obscured some of the finer physical details due to the widely varying composition of the fuels. The SOM was able to find a descriptive classification model which has the potential for practical recognition and perhaps prediction of fuel properties. PMID:28603295

Effect of broadened-specification fuels on aircraft engines and fuel systems

NASA Technical Reports Server (NTRS)

Rudey, R. A.

1979-01-01

A wide variety of studies on the potential effects of broadened-specification fuels on future aircraft engines and fuel systems are summarized. The compositions and characteristics of aircraft fuels that may be derived from current and future crude-oil sources are described, and the most critical properties that may effect aircraft engines and fuel systems are identified and discussed. The problems that are most likely to be encountered because of changes in selected fuel properties are explored; and the related effects on engine performance, component durability and maintenance, and aircraft fuel-system performance are examined. The ability of current technology to accept possible future fuel specification changes is assessed and selected technological advances that can reduce the severity of the potential problems are illustrated.

Effect of broadened-specification fuels on aircraft engines and fuel systems

NASA Technical Reports Server (NTRS)

Rudey, R. A.

1979-01-01

A wide variety of studies on the potential effects of broadened-specification fuels on future aircraft engines and fuel systems are summarized. The compositions and characteristics of aircraft fuels that may be derived from current and future crude-oil sources are described, and the most critical properties that may affect aircraft engines and fuel systems are identified and discussed. The problems that are most likely to be encountered because of changes in selected fuel properties are described; and the related effects on engine performance, component durability and maintenance, and aircraft fuel-system performance are discussed. The ability of current technology to accept possible future fuel-specification changes is discussed, and selected technological advances that can reduce the severity of the potential problems are illustrated.

Pressure and temperature effects on fuels with varying octane sensitivity at high load in SI engines

DOE PAGES

Szybist, James P.; Splitter, Derek A.

2017-01-06

The octane sensitivity (S), defined as the difference between the Research Octane Number (RON) and the Motor Octane Number (MON), is of increasing interest in spark ignition (SI) engines because of its relevance to knock resistance at boosted high load conditions. In this study, three fuels with nearly constant RON (99.2-100) and varying S (S = 0, 6.5, and 12) are operated at the knock limited spark advance (KLSA) at nominal engine loads of 10, 15, and 20 bar IMEP in a single cylinder SI engine with side-mount direct injection fueling, at λ =1 stoichiometry. At each load condition, themore » intake manifold temperature is swept from 35 °C to 95 °C to alter the temperature and pressure history of the charge. Results show that at the 10 bar IMEP condition, knock resistance is inversely proportional to fuel S where the S=0 fuel is the most knock resist, but as load increases the trend reverses and knock resistance becomes proportional to fuel S, and the S=12 fuel is the most knock resistant. The reversal of knock resistance as a function of S with load it is attributed to changing fuel ignition delay, as bulk gas intermediate temperature heat release (ITHR) is observed for the S = 0 several crank angles prior to the spark command and ITHR magnitude is a function of increasing intake temperature. As intake temperature continued to increase, the S=0 fuel transitioned from ITHR to low-temperature heat release (LTHR) prior to the spark event. At the highest load and intake temperature, 95 C, the S=0 fuel exhibits distinct LTHR and negative temperature coefficient (NTC), and the intermediate S value fuel (S=6.5) exhibited distinct ITHR behavior several crank angles prior to the spark command. However, for the tested conditions, the S=12 fuel exhibits neither ITHR nor LTHR. To understand the measured trends, chemical kinetic modeling is used to elucidate the fuel specific dependencies on in-cylinder temperature and pressure history. Lastly, the bulk gas composition change that occurs for fuels and conditions exhibiting ITHR and LTHR is analyzed in the modeling, including their implications on flame speed and combustion stability at late phasing. Furthermore, the combined findings illustrate the commonality and utility of fuel S, ITHR, LTHR, and NTC across a wide range of conditions, and the associated implications of fuel S in highly boosted modern GDI SI engines relative to the RON and MON tests.« less

Methane - fuel for the future

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGeer, P.; Durbin, E.

1982-01-01

The 20 invited papers presented at the world conference on alternative fuel entitled 'Methane - fuel for the future' form the basis of this book. Papers discuss: the availability of alternative fuels (natural gas, biomass conversion to methane, methane from coal conversion); technological adaptions for alternative fuels (e.g. natural gas fueled engines, methane and diesel engines); commercial experience with alternative fuel programs. (e.g. retailing of methane); and some national programs for alternative fuels. One paper has been abstracted separately.

Food for thought: Impact of metabolism on neuronal excitability.

PubMed

Katsu-Jiménez, Yurika; Alves, Renato M P; Giménez-Cassina, Alfredo

2017-11-01

Neuronal excitability is a highly demanding process that requires high amounts of energy and needs to be exquisitely regulated. For this reason, brain cells display active energy metabolism to support their activity. Independently of their roles as energy substrates, compelling evidence shows that the nature of the fuels that neurons use contribute to fine-tune neuronal excitability. Crosstalk of neurons with glial populations also plays a prominent role in shaping metabolic flow in the brain. In this review, we provide an overview on how different carbon substrates and metabolic pathways impact neurotransmission, and the potential implications for neurological disorders in which neuronal excitability is deregulated, such as epilepsy. Copyright © 2017 Elsevier Inc. All rights reserved.

Fuel buildup and potential fire behavior after stand-replacing fires, logging fire-killed trees and herbicide shrub removal in Sierra Nevada forests

USGS Publications Warehouse

McGinnis, Thomas W.; Keeley, Jon E.; Stephens, Scott L.; Roller, Gary B.

2010-01-01

Typically, after large stand-replacing fires in mid-elevation Sierra Nevada forests, dense shrub fields occupy sites formerly occupied by mature conifers, until eventually conifers overtop and shade out shrubs. Attempting to reduce fuel loads and expedite forest regeneration in these areas, the USDA Forest Service often disrupts this cycle by the logging of fire-killed trees, replanting of conifers and killing of shrubs. We measured the effects of these treatments on live and dead fuel loads and alien species and modeled potential fire behavior and fire effects on regenerating forests. Sampling occurred in untreated, logged and herbicide-treated stands throughout the Sierra Nevada in four large fire areas 4–21 years after stand-replacing fires. Logging fire-killed trees significantly increased total available dead fuel loads in the short term but did not affect shrub cover, grass and forb cover, alien species cover or alien species richness. Despite the greater available dead fuel loads, fire behavior was not modeled to be different between logged and untreated stands, due to abundant shrub fuels in both logged and untreated stands. In contrast, the herbicide treatment directed at shrubs resulted in extremely low shrub cover, significantly greater alien species richness and significantly greater alien grass and forb cover. Grass and forb cover was strongly correlated with solar radiation on the ground, which may be the primary reason that grass and forb cover was higher in herbicide treated stands with low shrub and tree cover. Repeat burning exacerbated the alien grass problem in some stands. Although modeled surface fire flame lengths and rates of spread were found to be greater in stands dominated by shrubs, compared to low shrub cover conifer plantations, surface fire would still be intense enough to kill most trees, given their small size and low crown heights in the first two decades after planting.

Technology Status and Expected Greenhouse Gas Emissions of Battery, Plug-In Hybrid, and Fuel Cell Electric Vehicles

NASA Astrophysics Data System (ADS)

Lipman, Timothy E.

2011-11-01

Electric vehicles (EVs) of various types are experiencing a commercial renaissance but of uncertain ultimate success. Many new electric-drive models are being introduced by different automakers with significant technical improvements from earlier models, particularly with regard to further refinement of drivetrain systems and important improvements in battery and fuel cell systems. The various types of hybrid and all-electric vehicles can offer significant greenhouse gas (GHG) reductions when compared to conventional vehicles on a full fuel-cycle basis. In fact, most EVs used under most condition are expected to significantly reduce lifecycle GHG emissions. This paper reviews the current technology status of EVs and compares various estimates of their potential to reduce GHGs on a fuel cycle basis. In general, various studies show that battery powered EVs reduce GHGs by a widely disparate amount depending on the type of powerplant used and the particular region involved, among other factors. Reductions typical of the United States would be on the order of 20-50%, depending on the relative level of coal versus natural gas and renewables in the powerplant feedstock mix. However, much deeper reductions of over 90% are possible for battery EVs running on renewable or nuclear power sources. Plug-in hybrid vehicles running on gasoline can reduce emissions by 20-60%, and fuel cell EV reduce GHGs by 30-50% when running on natural gas-derived hydrogen and up to 95% or more when the hydrogen is made (and potentially compressed) using renewable feedstocks. These are all in comparison to what is usually assumed to be a more advanced gasoline vehicle "baseline" of comparison, with some incremental improvements by 2020 or 2030. Thus, the emissions from all of these EV types are highly variable depending on the details of how the electric fuel or hydrogen is produced.

Synthesis of fuels and feedstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutton, Andrew D.; Brooks, Ty; Jenkins, Rhodri

Disclosed herein are embodiments of a method for making fuels and feedstocks from readily available alcohol starting materials. In some embodiments, the method concerns converting alcohols to carbonyl-containing compounds and then condensing such carbonyl-containing compounds together to form oligomerized species. These oligomerized species can then be reduced using by-products from the conversion of the alcohol. In some embodiments, the method further comprises converting saturated, oligomerized, carbonyl-containing compounds to aliphatic fuels.

High power density fuel cell comprising an array of microchannels

DOEpatents

Morse, Jeffrey D.; Upadhye, Ravindra S.; Spadaccini, Christopher M.; Park, Hyung Gyu

2013-10-15

A fuel cell according to one embodiment includes a porous electrolyte support structure defining an array of microchannels, the microchannels including fuel and oxidant microchannels; fuel electrodes formed along some of the microchannels; and oxidant electrodes formed along other of the microchannels. A method of making a fuel cell according to one embodiment includes forming an array of walls defining microchannels therebetween using at least one of molding, stamping, extrusion, injection and electrodeposition; processing the walls to make the walls porous, thereby creating a porous electrolyte support structure; forming anode electrodes along some of the microchannels; and forming cathode electrodes along other of the microchannels. Additional embodiments are also disclosed.

Issues and Potential Program on Denatured Fuel Utilization.

DTIC Science & Technology

1978-12-01

HTGR fuel develop - ment program ; 4. coated particles of (U,Th)02 have been extensively tested as potential HTGR fuels . A detailed summary of the...current scrap and waste treatment requirements. dBase case for all HTGR (Prismatic Fuel Element) cases based on data in "Summary Program Plan...Alternate Program for HTGR Fuel Recycle," April 11, 1975, Draft. 19 a --- AC8NCi09 The principal factors that result in a nominally-higher cost for

Bioprocessing of Stichococcus bacillaris strain siva2011

PubMed Central

2014-01-01

Background Globally, the development of a cost-effective long-term renewable energy infrastructure is one of the most challenging problems faced by society today. Microalgae are rich in potential biofuel substrates such as lipids, including triacylglycerols (TAGs). Some of these algae also biosynthesize small molecule hydrocarbons. These hydrocarbons can often be used as liquid fuels, often with more versatility and by a more direct approach than some TAGs. However, the appropriate TAGs, accumulated from microalgae biomass, can be used as substrates for different kinds of renewable liquid fuels such as biodiesel and jet fuel. Results This article describes the isolation and identification of a lipid-rich, hydrocarbon-producing alga, Stichococcus bacillaris strain siva2011, together with its bioprocessing, hydrocarbon and fatty acid methyl ester (FAME) profiles. The S. bacillaris strain siva2011 was scaled-up in an 8 L bioreactor with 0.2% CO2. The C16:0, C16:3, C18:1, C18:2 and C18:3 were 112.2, 9.4, 51.3, 74.1 and 69.2 mg/g dry weight (DW), respectively. This new strain produced a significant amount of biomass of 3.79 g/L DW on day 6 in the 8 L bioreactor and also produced three hydrocarbons. Conclusions A new oil-rich microalga S. bacillaris strain siva2011 was discovered and its biomass has been scaled-up in a newly designed balloon-type bioreactor. The TAGs and hydrocarbons produced by this organism could be used as substrates for jet fuel or biodiesel. PMID:24731690

The Finite Element Modelling and Dynamic Characteristics Analysis about One Kind of Armoured Vehicles’ Fuel Tanks

NASA Astrophysics Data System (ADS)

Gao, Yang; Ge, Zhishang; Zhai, Weihao; Tan, Shiwang; Zhang, Feng

2018-01-01

The static and dynamic characteristics of fuel tank are studied for the armoured vehicle in this paper. The CATIA software is applied to build the CAD model of the armoured vehicles’ fuel tank, and the finite element model is established in ANSYS Workbench. The finite element method is carried out to analyze the static and dynamic mechanical properties of the fuel tank, and the first six orders of mode shapes and their frequencies are also computed and given in the paper, then the stress distribution diagram and the high stress areas are obtained. The results of the research provide some references to the fuel tanks’ design improvement, and give some guidance for the installation of the fuel tanks on armoured vehicles, and help to improve the properties and the service life of this kind of armoured vehicles’ fuel tanks.

Production of Liquid Synthetic Fuels from Carbon, Water and Nuclear Power on Ships and at Shore Bases for Military and Potential Commercial Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Locke Bogart, S.; Schultz, Ken; Brown, Lloyd

2006-07-01

It is demonstrable that synthetic fuels (jet/diesel/gasoline {approx_equal} (CH{sub 2}){sub n}) can be produced from carbon, water, and nuclear energy. What remains to be shown is that all system processes are scalable, integrable, and economical. Sources of carbon include but are not limited to CO{sub 2} from the atmosphere or seawater, CO{sub 2} from fossil-fired power plants, and elemental carbon from coal or biomass. For mobile defense (Navy) applications, the ubiquitous atmosphere is our chosen carbon source. For larger-scale sites such as Naval Advance Bases, the atmosphere may still be the choice should other sources not be readily available. However, at many locations suitable for defense and, potentially, commercial syn-fuel production, far higher concentrations of carbon may be available. The rationale for this study was manifold: fuel system security from terrorism and possible oil embargoes; rising demand and, eventually, peaking supply of conventional petroleum; and escalating costs and prices of fuels. For these reasons, the initial parts of the study were directed at Syn-fuel production for mobile Naval platforms and shore sites such as Rokkasho, Japan (as an exemplar). Nuclear reactors would provide the energy for H{sub 2} from water-splitting, Membrane Gas Absorption (MGA) would extract CO{sub 2} from the atmosphere, the Reverse Water-Gas Reaction (RWGR) would convert the CO{sub 2} to CO, and the resultant H{sub 2} and CO feeds would be converted to (CH{sub 2})n by the Fischer-Tropsch reaction. Many of these processes exist at commercial scale. Some, particularly MGA and RWGR, have been demonstrated at the bench-scale, requiring up-scaling. Likewise, the demonstration of an integrated system at some scale is yet to be done. For ship-based production, it has been shown that the system should be viable and, under reasonable assumptions, both scalable and economical for defense fuels. For the assumptions in the study, fuel cost estimates range from {approx}more » $2.55 to $$4.75 per gallon with a nominal cost of {approx} $$3.65 per gallon. For large installations and advanced nuclear power and hydrogen production systems (high temperature reactors and thermo-chemical hydrogen production), then fuel production might be produced at near-commercial fuel prices. For the H2-MHR and plausible assumptions and estimates of CO{sub 2} extraction and fuel synthesis capital and operating costs, such fuels might have nominal and low production costs ranging from {approx} $2.40 to $$1.70 per gallon, respectively, for a Public Sector Fixed Charge Rate of 5%. Next, it was shown that for CO{sub 2} provided from a fossil-fired power plant, a CO{sub 2} 'disposal' fee of $$30/tonne and a Fixed Charge Rate of 10%, then syn-fuel might be produced at {approx} $3.00 and $2.45 (nominal cost values) and $1.90 and $$1.85 (low cost values) per gallon by LWRs and H2-MHRs, respectively. Last, it was shown that nuclear-produced H{sub 2} and O{sub 2} could convert coal to liquid fuels at very low cost. For a Fixed Charge Rate of 10% and nominal plant costs, fuel costs ranged from {approx} $$1.60 (LWR) per gallon to {approx} $$1.30 (H2-MHR) for an assumed CO{sub 2} avoidance credit of $$30/Tonne. Our studies have shown that the addition of nuclear-produced hydrogen and oxygen to the coal syn-fuel process can greatly reduce CO{sub 2} production and, for modest CO{sub 2} credit, can further reduce the cost of the syn-fuel. Capturing CO{sub 2} from stack gas or even the air will further reduce the amount of CO{sub 2} that must be dealt with. This last case is independent of the price of fossil fuels and liquid fuel production costs and prices will have been capped. Of possibly even greater importance, the carbon fuel cycle will have been closed, thus minimizing or eliminating concerns with Global Climate Change. (authors)« less

European opportunities for fuel cell commercialisation

NASA Astrophysics Data System (ADS)

Gibbs, C. E.; Steel, M. C. F.

1992-01-01

The European electricity market is changing. This paper will look at the background to power generation in Europe and highlight the recent factors which have entered the market to promote change. The 1990s seem to offer great possibilities for fuel cell commercialisation. Awareness of environmental problems has never been greater and there is growing belief that fuel cell technology can contribute to solving some of these problems. Issues which have caused the power industry in Europe to re-think its methods of generation include: concern over increasing carbon dioxide emissions and their contribution to the greenhouse effect; increasing SO x and NO x emissions and the damage cause by acid rain; the possibility of adverse effects on health caused by high voltage transmission lines; environmental restrictions to the expansion of hydroelectric schemes; public disenchantment with nuclear power following the Chernobyl accident; avoidance of dependence on imported oil following the Gulf crisis and a desire for fuel flexibility. All these factors are hastening the search for clean, efficient, modular power generators which can be easily sited close to the electricity consumer and operated using a variety of fuels. It is not only the power industry which is changing. A tightening of the legislation concerning emissions from cars is encouraging European auto companies to develop electric vehicles, some of which may be powered by fuel cells. Political changes, such as the opening up of Eastern Europe will also expand the market for low-emission, efficient power plants as attempts are made to develop and clean up that region. Many Europeans organisations are re-awakening their interest, or strengthening their activities, in the area of fuel cells because of the increasing opportunities offered by the European market. While some companies have chosen to buy, test and demonstrate Japanese or American fuel cell stacks with the aim of gaining operational experience and developing European sub-systems, others have chosen to develop their own novel cell technology. This paper will survey the extent of the fuel cell activities in Europe and emphasise the particular markets which fuel cell manufacturers are targeting. Demand for fuel cells in defence and military applications will be the first sector to be commercially viable — European companies such as Siemens, Elenco and VSEL are already marketing AFC or PEM systems for naval and aerospace applications. The small-scale CHP sector is also a likely early market for fuel cell plant. Co-generation fuel cells are of great interest to gas companies like ENAGAS and British Gas looking to promote sales of gas by installing on-site gas-fired generators on their customers' premises. The market for utility scale fuel cell plants is expected to develop later in the decade. The largest demonstration planned for Europe is the 1 MW PAFC for Milan, due to come onstream in 1992. MBB GmbH is considering developing MW-scale MCFC plants with the US company ERC — a 2 MW demonstration is planned for the end of 1993. The potential market for utility fuel cells is large — installation rates could reach 500-1000 MW/year by the turn of the century. Fuel cells will probably not achieve significant use in transport applications in Europe until after the turn of the century unless very stringent emissions legislation for vehicles is introduced. The likely early markets for fuel cells in the transport sector seem to be for delivery and fleet vehicles. Examples of European projects in this area include the Amsterdam city bus project which will use Elenco's AFC technology and Siemens' fork lift truck which will incorporate a PEM fuel cell. Fuel cells also link conveniently with renewable energy systems — coupled with an electrolyser a fuel cell can store solar, wind or wave power. The electrolysis proces is used to generate hydrogen from water at times of surplus energy while the fuel cell consumes hydrogen fuel when demand for power exceeds supply. The SWB solar hydrogen project in Germany is testing PAFC and AFC stacks in this application. Several problems remain before fuel cell technology can fulfil its maximum potential market. For PAFC there is a need to reduce plant capital costs and to verify lifetimes and reliability. KTI's 25 kW demonstration at Delft and the Milan 1 MW plant will increase European knowledge and experience of PAFC plant operation. For MCFC there are materials problems to be solved and work needs to be carried out on the best way to scale up plants. Projects underway in the Netherlands, Germany, Italy and elsewhere should bring Europe to the forefront of MCFC technology. SOFC requires further study in the area of design configurations and fabrication techniques. Research on these aspects is underway in Denmark, Switzerland, Germany, the Netherlands and the UK. For PEM technology work on reducing precious metal loadings and selecting the best polymer membrane is required — an area in which Johnson Matthey is involved. For all fuel cell technologies there needs to be a greater awareness among power suppliers, consumers, legislators and environmentalists of the advantages that fuel cells can offer. The increase in activity among European organisations in developing, demonstrating, testing and optimising fuel cell systems will encourage a greater awareness of the technology and bring commercialisation closer to reality.

Fuel treatment guidebook: illustrating treatment effects on fire hazard

Treesearch

Morris Johnson; David L. Peterson; Crystal Raymond

2009-01-01

The Guide to Fuel Treatments (Johnson and others 2007) analyzes potential fuel treatments and the potential effects of those treatments for dry forest lands in the Western United States. The guide examines low- to mid-elevation dry forest stands with high stem densities and heavy ladder fuels, which are currently common due to fire exclusion and various land management...

Environmental implications of alternative-fueled automobiles: Air quality and greenhouse gas tradeoffs

DOE Office of Scientific and Technical Information (OSTI.GOV)

MaClean, H.L.; Lave, L.B.

The authors analyze alternative fuel-powerstrain options for internal combustion engine automobiles. Fuel/engine efficiency, energy use, pollutant discharges, and greenhouse gas emissions are estimated for spark and compression ignited, direct injected (DI), and indirect injected (II) engines fueled by conventional and reformulated gasoline, reformulated diesel, compressed natural gas (CNG), and alcohols. Since comparisons of fuels and technologies in dissimilar vehicles are misleading, the authors hold emissions level, range, vehicle size class, and style constant. At present, CNG vehicles have the best exhaust emissions performance while DI diesels have the worst. Compared to a conventional gasoline fueled II automobile, greenhouse gases couldmore » be reduced by 40% by a DI CNG automobile and by 25% by a DI diesel. Gasoline- and diesel-fueled automobiles are able to attain long ranges with little weight or fuel economy penalty. CNG vehicles have the highest penalty for increasing range, due to their heavy fuel storage systems, but are the most attractive for a 160-km range. DI engines, particularly diesels, may not be able to meet strict emissions standards, at least not without lowering efficiency.« less

Liquid-fueled SOFC power sources for transportation

NASA Astrophysics Data System (ADS)

Myles, K. M.; Doshi, R.; Kumar, R.; Krumpelt, M.

Traditionally, fuel cells have been developed for space or stationary terrestrial applications. As the first commercial 200-kW systems were being introduced by ONSI and Fuji Electric, the potentially much larger, but also more challenging, application in transportation was beginning to be addressed. As a result, fuel cell-powered buses have been designed and built, and R&D programs for fuel cell-powered passenger cars have been initiated. The engineering challenge of eventually replacing the internal combustion engine in buses, trucks, and passenger cars with fuel cell systems is to achieve much higher power densities and much lower costs than obtainable in systems designed for stationary applications. At present, the leading fuel cell candidate for transportation applications is, without question, the polymer electrolyte fuel cell (PEFC). Offering ambient temperature start-up and the potential for a relatively high power density, the polymer technology has attracted the interest of automotive manufacturers worldwide. But the difficulties of fuel handling for the PEFC have led to a growing interest in exploring the prospects for solid oxide fuel cells (SOFCs) operating on liquid fuels for transportation applications. Solid oxide fuel cells are much more compatible with liquid fuels (methanol or other hydrocarbons) and are potentially capable of power densities high enough for vehicular use. Two SOFC options for such use are discussed in this report.

Silanes as Fuel for Aerospace Propulsion

NASA Astrophysics Data System (ADS)

Simone, Domenico; Bruno, Claudio; Hidding, Bernhard

In the light of recently revived interest in high energy density fuels for aerospace applications1,2), a new look is being given at unconventional fuels. Among the latter are hydrides, because their hydrogen content and density. Among hydrides silanes are of interest because of their combustion and energetic properties.Silanes are silicon hydrides organized in molecular chains similar to those of hydrocarbons; at STP, lower silanes (SiH4, Si2H6) are gaseous and extremely pyrophoric; with increasing chain length, silanes become liquid from trisilane (Si3H8) on, and therefore easily pumped. Another important feature of silanes is the large amount of hydrogen theoretically available by thermal decomposition: in fact at moderate temperatures (about 500 K) the chains begin to break and at 700 K their decomposition is complete, yielding silicon and gaseous hydrogen, useful for propulsion in combination with air nitrogen and oxygen. This last feature, if confirmed, could identify silanes not only as energy carriers but also components in bi-fuel systems. To assess their theoretical performance, simulations were conducted assuming silanes and/or their thermal decomposition products in combination with various oxidizers and air. Preliminary results are suggestive of their potential for some specialized applications, especially where compactness is at premium.

Potential of spark ignition engine for increased fuel efficiency. Final report, January-October 1978

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, T. Jr.; Cole, D.; Bolt, J.A.

The objective of this study was to assess the potential of the spark ignition engine to deliver maximum fuel efficiency at 1981 Statutory Emission Standards in the 1983-1984 timeframe and beyond that to 1990. Based on the results of an extensive literature search, manufacturer's known product plans, and fuel economies of 1978 engines as a baseline, proposed methods of attaining fuel economy while complying with the future standards were ascertained. Methods of engine control optimization, engine design optimization as well as methods of varying engine parameters were considered. The potential improvements in fuel economy associated with these methods, singly andmore » in combination, were determined and are expressed as percentage changes of the fuel economy of the baseline engines. A summary of the principal conclusions are presented, followed by a description of the engine baseline reference, analysis and projection of fuel economy improvements, and a preliminary assessment of the impact of fuel economy benefits on manufacturing cost.« less

Computer analysis of effects of altering jet fuel properties on refinery costs and yields

NASA Technical Reports Server (NTRS)

Breton, T.; Dunbar, D.

1984-01-01

This study was undertaken to evaluate the adequacy of future U.S. jet fuel supplies, the potential for large increases in the cost of jet fuel, and to what extent a relaxation in jet fuel properties would remedy these potential problems. The results of the study indicate that refiners should be able to meet jet fuel output requirements in all regions of the country within the current Jet A specifications during the 1990-2010 period. The results also indicate that it will be more difficult to meet Jet A specifications on the West Coast, because the feedstock quality is worse and the required jet fuel yield (jet fuel/crude refined) is higher than in the East. The results show that jet fuel production costs could be reduced by relaxing fuel properties. Potential cost savings in the East (PADDs I-IV) through property relaxation were found to be about 1.3 cents/liter (5 cents/gallon) in January 1, 1981 dollars between 1990 and 2010. However, the savings from property relaxation were all obtained within the range of current Jet A specifications, so there is no financial incentive to relax Jet A fuel specifications in the East. In the West (PADD V) the potential cost savings from lowering fuel quality were considerably greater than in the East. Cost savings from 2.7 to 3.7 cents/liter (10-14 cents/gallon) were found. In contrast to the East, on the West Coast a significant part of the savings was obtained through relaxation of the current Jet A fuel specifications.

Market impacts of hypothetical fuel treatment thinning programs on federal lands in the western United States

Treesearch

Peter J. Ince; Henry Spelter; Kenneth Skog; Andrew Kramp; Dennis P. Dykstra

2000-01-01

This paper addresses the economics of forest fuel thinning programs on federal lands in the U.S. West, and presents a model of regional timber and product market impacts. The issue of economics is vital to the debate about fire management, and this paper presents market implications of two alternative silvicultural strategies, even-aged and uneven-aged...

California Hydrogen Infrastructure Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heydorn, Edward C

2013-03-12

Air Products and Chemicals, Inc. has completed a comprehensive, multiyear project to demonstrate a hydrogen infrastructure in California. The specific primary objective of the project was to demonstrate a model of a real-world retail hydrogen infrastructure and acquire sufficient data within the project to assess the feasibility of achieving the nation's hydrogen infrastructure goals. The project helped to advance hydrogen station technology, including the vehicle-to-station fueling interface, through consumer experiences and feedback. By encompassing a variety of fuel cell vehicles, customer profiles and fueling experiences, this project was able to obtain a complete portrait of real market needs. The projectmore » also opened its stations to other qualified vehicle providers at the appropriate time to promote widespread use and gain even broader public understanding of a hydrogen infrastructure. The project engaged major energy companies to provide a fueling experience similar to traditional gasoline station sites to foster public acceptance of hydrogen. Work over the course of the project was focused in multiple areas. With respect to the equipment needed, technical design specifications (including both safety and operational considerations) were written, reviewed, and finalized. After finalizing individual equipment designs, complete station designs were started including process flow diagrams and systems safety reviews. Material quotes were obtained, and in some cases, depending on the project status and the lead time, equipment was placed on order and fabrication began. Consideration was given for expected vehicle usage and station capacity, standard features needed, and the ability to upgrade the station at a later date. In parallel with work on the equipment, discussions were started with various vehicle manufacturers to identify vehicle demand (short- and long-term needs). Discussions included identifying potential areas most suited for hydrogen fueling stations with a focus on safe, convenient, fast-fills. These potential areas were then compared to and overlaid with suitable sites from various energy companies and other potential station operators. Work continues to match vehicle needs with suitable fueling station locations. Once a specific site was identified, the necessary agreements could be completed with the station operator and expected station users. Detailed work could then begin on the site drawings, permits, safety procedures and training needs. Permanent stations were successfully installed in Irvine (delivered liquid hydrogen), Torrance (delivered pipeline hydrogen) and Fountain Valley (renewable hydrogen from anaerobic digester gas). Mobile fueling stations were also deployed to meet short-term fueling needs in Long Beach and Placerville. Once these stations were brought online, infrastructure data was collected and reported to DOE using Air Products Enterprise Remote Access Monitoring system. Feedback from station operators was incorporated to improve the station user's fueling experience.« less

A review of phase separation issues in aviation gasoline fuel and motor gasoline fuels in aviation

NASA Astrophysics Data System (ADS)

Thanikasalam, K.; Rahmat, M.; Fahmi, A. G. Mohammad; Zulkifli, A. M.; Shawal, N. Noor; Ilanchelvi, K.; Ananth, M.; Elayarasan, R.

2018-05-01

In an attempt to bring in sustainable energy resources into the current combustibles mix, recent European legislations make obligatory the addition of biogenic fuels into traditional fossil gasoline. The preferred biogenic fuel, for economic reasons, is predominantly ethanol. Even though likened to fossil gasoline constituents, ethanol has a dissimilar chemical formulation that may lead to a potentially hazardous physicochemical phenomenon, particularly in the presence of water. Owing to increased financially driven propensity to utilize motor vehicle gasoline as aviation gasoline fuel, this may result in potentially hazardous situations, specifically in running smaller or compact General Aviation aircraft. The potential risks posed by ethanol admixtures in aircraft are phase separation and carburettor icing. Gasoline mixed with ethanol is also prone to an increased vulnerability to vapor lock that happens when fuel turns into vapor in the fuel pumps due to high temperatures and lessened ambient pressure at high altitudes. This article provides a literature review on phase separation issues in aviation gasoline fuel and motor gasoline fuels in aviation.

VOLATILE ORGANIC COMPOUNDS FROM VEGETATION IN SOUTHERN YUNNAN PROVINCE, CHINA: EMISSION RATES AND SOME POTENTIAL REGIONAL IMPLICATIONS

EPA Science Inventory

Little information is currently available regarding emissions of biogenic volatile organic compounds (BVOCs) in southern Asia. To address the need for BVOC emission estimates in regional atmospheric chemistry simulations, 95 common plant species were screened for emissions of BVO...

The Contribution of Non-Representational Theories in Education: Some Affective, Ethical and Political Implications

ERIC Educational Resources Information Center

Zembylas, Michalinos

2017-01-01

This paper follows recent debates around theorizations of "affect" and its distinction from "emotion" in the context of non-representational theories (NRT) to exemplify how the ontologization of affects creates important openings of ethical and political potential in educators' efforts to make productive interventions in…

Early decline in glucose transport and metabolism precedes shift to ketogenic system in female aging and Alzheimer's mouse brain: implication for bioenergetic intervention.

PubMed

Ding, Fan; Yao, Jia; Rettberg, Jamaica R; Chen, Shuhua; Brinton, Roberta Diaz

2013-01-01

We previously demonstrated that mitochondrial bioenergetic deficits in the female brain accompanied reproductive senescence and was accompanied by a shift from an aerobic glycolytic to a ketogenic phenotype. Herein, we investigated the relationship between systems of fuel supply, transport and mitochondrial metabolic enzyme expression/activity during aging (3-15 months) in the hippocampus of nontransgenic (nonTg) background and 3xTgAD female mice. Results indicate that during female brain aging, both nonTg and 3xTgAD brains undergo significant decline in glucose transport, as detected by FDG-microPET, between 6-9 months of age just prior to the transition into reproductive senescence. The deficit in brain metabolism was sustained thereafter. Decline in glucose transport coincided with significant decline in neuronal glucose transporter expression and hexokinase activity with a concomitant rise in phosphorylated/inactivated pyruvate dehydrogenase. Lactate utilization declined in parallel to the decline in glucose transport suggesting lactate did not serve as an alternative fuel. An adaptive response in the nonTg hippocampus was a shift to transport and utilization of ketone bodies as an alternative fuel. In the 3xTgAD brain, utilization of ketone bodies as an alternative fuel was evident at the earliest age investigated and declined thereafter. The 3xTgAD adaptive response was to substantially increase monocarboxylate transporters in neurons while decreasing their expression at the BBB and in astrocytes. Collectively, these data indicate that the earliest change in the metabolic system of the aging female brain is the decline in neuronal glucose transport and metabolism followed by decline in mitochondrial function. The adaptive shift to the ketogenic system as an alternative fuel coincided with decline in mitochondrial function. Translationally, these data provide insights into the earliest events in bioenergetic aging of the female brain and provide potential targets for preventing shifts to less efficient bioenergetic fuels and transition to the ketogenic phenotype of the Alzheimer's brain.

Behavioral Attitudes and Preferences in Cooking Practices with Traditional Open-Fire Stoves in Peru, Nepal, and Kenya: Implications for Improved Cookstove Interventions

PubMed Central

Rhodes, Evelyn L.; Dreibelbis, Robert; Klasen, Elizabeth; Naithani, Neha; Baliddawa, Joyce; Menya, Diana; Khatry, Subarna; Levy, Stephanie; Tielsch, James M.; Miranda, J. Jaime; Kennedy, Caitlin; Checkley, William

2014-01-01

Global efforts are underway to develop and promote improved cookstoves which may reduce the negative health and environmental effects of burning solid fuels on health and the environment. Behavioral studies have considered cookstove user practices, needs and preferences in the design and implementation of cookstove projects; however, these studies have not examined the implications of the traditional stove use and design across multiple resource-poor settings in the implementation and promotion of improved cookstove projects that utilize a single, standardized stove design. We conducted in-depth interviews and direct observations of meal preparation and traditional, open-fire stove use of 137 women aged 20–49 years in Kenya, Peru and Nepal prior in the four-month period preceding installation of an improved cookstove as part of a field intervention trial. Despite general similarities in cooking practices across sites, we identified locally distinct practices and norms regarding traditional stove use and desired stove improvements. Traditional stoves are designed to accommodate specific cooking styles, types of fuel, and available resources for maintenance and renovation. The tailored stoves allow users to cook and repair their stoves easily. Women in each setting expressed their desire for a new stove, but they articulated distinct specific alterations that would meet their needs and preferences. Improved cookstove designs need to consider the diversity of values and needs held by potential users, presenting a significant challenge in identifying a “one size fits all” improved cookstove design. Our data show that a single stove design for use with locally available biomass fuels will not meet the cooking demands and resources available across the three sites. Moreover, locally produced or adapted improved cookstoves may be needed to meet the cooking needs of diverse populations while addressing health and environmental concerns of traditional stoves. PMID:25286166

Review of SiCf/SiCm corrosion, erosion and erosion-corrosion in high temperature helium relevant to GFR conditions

NASA Astrophysics Data System (ADS)

Fitzgerald, Kerr; Shepherd, Daniel

2018-01-01

The good thermal, mechanical and nuclear properties of silicon carbide composites (SiCf/SiCm) has led to their proposal as a gas-cooled fast reactor (GFR) fuel cladding material. Accordingly, previous studies on the corrosion, erosion and erosion-corrosion of SiCf/SiCm have been reviewed. A significant amount of corrosion data was compared for various SiCf/SiCm types tested under different conditions, which suggested that it may be suitable for use in a GFR. However some issues remain, specifically the potential for removal by oxidation of the pyrolytic carbon (PyC) interphase below 900 °C and highly damaging active oxidation at temperatures above 1200 °C. Few relevant papers were found on the erosion and erosion-corrosion behaviour of SiCf/SiCm, though those that were did indicate improved erosion resistance compared to metals. However, most data concerned particulate rather than gas erosion, and at relatively low temperatures. Exacerbation of erosion by corrosion (and vice versa) is hypothesised due to both phenomena potentially causing and being worsened by increased composite porosity. The possibility for this to be further exacerbated mechanically was also identified e.g. by surface damage or by crack formation and growth. The potential impact of irradiation in fast reactor conditions also needs to be better understood. Overall, limited data was found that is representative of anticipated GFR conditions and only in the form of separate effect corrosion tests, thus highlighting the need for erosion and combined effect experiments to progress SiCf/SiCm towards qualification as GFR fuel cladding. Finally, some potential means for improving performance have been identified including environmental adjustment and/or alternative composite design.

Fuels research: Fuel thermal stability overview

NASA Technical Reports Server (NTRS)

Cohen, S. M.

1980-01-01

Alternative fuels or crude supplies are examined with respect to satisfying aviation fuel needs for the next 50 years. The thermal stability of potential future fuels is discussed and the effects of these characteristics on aircraft fuel systems are examined. Advanced fuel system technology and design guidelines for future fuels with lower thermal stability are reported.

Nuclear safety considerations in the conceptual design of a fast reactor for space electric power and propulsion

NASA Technical Reports Server (NTRS)

Hsieh, T.-M.; Koenig, D. R.

1977-01-01

Some nuclear safety aspects of a 3.2 mWt heat pipe cooled fast reactor with out-of-core thermionic converters are discussed. Safety related characteristics of the design including a thin layer of B4C surrounding the core, the use of heat pipes and BeO reflector assembly, the elimination of fuel element bowing, etc., are highlighted. Potential supercriticality hazards and countermeasures are considered. Impacts of some safety guidelines of space transportation system are also briefly discussed, since the currently developing space shuttle would be used as the primary launch vehicle for the nuclear electric propulsion spacecraft.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szybist, James P.; Splitter, Derek A.

The octane sensitivity (S), defined as the difference between the Research Octane Number (RON) and the Motor Octane Number (MON), is of increasing interest in spark ignition (SI) engines because of its relevance to knock resistance at boosted high load conditions. In this study, three fuels with nearly constant RON (99.2-100) and varying S (S = 0, 6.5, and 12) are operated at the knock limited spark advance (KLSA) at nominal engine loads of 10, 15, and 20 bar IMEP in a single cylinder SI engine with side-mount direct injection fueling, at λ =1 stoichiometry. At each load condition, themore » intake manifold temperature is swept from 35 °C to 95 °C to alter the temperature and pressure history of the charge. Results show that at the 10 bar IMEP condition, knock resistance is inversely proportional to fuel S where the S=0 fuel is the most knock resist, but as load increases the trend reverses and knock resistance becomes proportional to fuel S, and the S=12 fuel is the most knock resistant. The reversal of knock resistance as a function of S with load it is attributed to changing fuel ignition delay, as bulk gas intermediate temperature heat release (ITHR) is observed for the S = 0 several crank angles prior to the spark command and ITHR magnitude is a function of increasing intake temperature. As intake temperature continued to increase, the S=0 fuel transitioned from ITHR to low-temperature heat release (LTHR) prior to the spark event. At the highest load and intake temperature, 95 C, the S=0 fuel exhibits distinct LTHR and negative temperature coefficient (NTC), and the intermediate S value fuel (S=6.5) exhibited distinct ITHR behavior several crank angles prior to the spark command. However, for the tested conditions, the S=12 fuel exhibits neither ITHR nor LTHR. To understand the measured trends, chemical kinetic modeling is used to elucidate the fuel specific dependencies on in-cylinder temperature and pressure history. Lastly, the bulk gas composition change that occurs for fuels and conditions exhibiting ITHR and LTHR is analyzed in the modeling, including their implications on flame speed and combustion stability at late phasing. Furthermore, the combined findings illustrate the commonality and utility of fuel S, ITHR, LTHR, and NTC across a wide range of conditions, and the associated implications of fuel S in highly boosted modern GDI SI engines relative to the RON and MON tests.« less

Synthesis and electrochemical characterization of TixTayAlzN1-δOγ for fuel cell catalyst supports

NASA Astrophysics Data System (ADS)

Wakabayashi, Ryo H.; Abruña, Héctor D.; DiSalvo, Francis J.

2017-02-01

Quinary TixTayAlzN1-δOγ of various compositions have been prepared by a co-precipitation method followed by ammonolysis. The nitride samples were examined as potential catalyst supports in polymer electrolyte membrane fuel cells. The nitride products crystallized in the rock salt (NaCl) structure over a wide range of compositions. The addition of Ta and Al was highly beneficial towards improving the chemical and electrochemical stability of TiN, without a significant loss of electrical conductivity. Platinum particles were successfully deposited on the (oxy)nitride samples, and the composite samples at some compositions were found to be comparable to Pt/carbon in their stability and catalytic activity even without optimizing the Pt deposition and dispersion processes.