Predicting hydration Gibbs energies of alkyl-aromatics using molecular simulation: a comparison of current force fields and the development of a new parameter set for accurate solvation data.

PubMed

Garrido, Nuno M; Jorge, Miguel; Queimada, António J; Gomes, José R B; Economou, Ioannis G; Macedo, Eugénia A

2011-10-14

The Gibbs energy of hydration is an important quantity to understand the molecular behavior in aqueous systems at constant temperature and pressure. In this work we review the performance of some popular force fields, namely TraPPE, OPLS-AA and Gromos, in reproducing the experimental Gibbs energies of hydration of several alkyl-aromatic compounds--benzene, mono-, di- and tri-substituted alkylbenzenes--using molecular simulation techniques. In the second part of the paper, we report a new model that is able to improve such hydration energy predictions, based on Lennard Jones parameters from the recent TraPPE-EH force field and atomic partial charges obtained from natural population analysis of density functional theory calculations. We apply a scaling factor determined by fitting the experimental hydration energy of only two solutes, and then present a simple rule to generate atomic partial charges for different substituted alkyl-aromatics. This rule has the added advantages of eliminating the unnecessary assumption of fixed charge on every substituted carbon atom and providing a simple guideline for extrapolating the charge assignment to any multi-substituted alkyl-aromatic molecule. The point charges derived here yield excellent predictions of experimental Gibbs energies of hydration, with an overall absolute average deviation of less than 0.6 kJ mol(-1). This new parameter set can also give good predictive performance for other thermodynamic properties and liquid structural information.

Emissions and temperature benefits: The role of wind power in China.

PubMed

Duan, Hongbo

2017-01-01

As a non-fossil technology, wind power has an enormous advantage over coal because of its role in climate change mitigation. Therefore, it is important to investigate how substituting wind power for coal-fired electricity will affect emission reductions, changes in radiative forcing and rising temperatures, particularly in the context of emission limits. We developed an integrated methodology that includes two parts: an energy-economy-environmental (3E) integrated model and an emission-temperature response model. The former is used to simulate the dynamic relationships between economic output, wind energy and greenhouse gas (GHG) emissions; the latter is used to evaluate changes in radiative forcing and warming. Under the present development projection, wind energy cannot serve as a major force in curbing emissions, even under the strictest space-restraining scenario. China's temperature contribution to global warming will be up to 21.76% if warming is limited to 2 degrees. With the wind-for-coal power substitution, the corresponding contribution to global radiative forcing increase and temperature rise will decrease by up to 10% and 6.57%, respectively. Substituting wind power for coal-fired electricity has positive effects on emission reductions and warming control. However, wind energy alone is insufficient for climate change mitigation. It forms an important component of the renewable energy portfolio used to combat global warming. Copyright © 2016 Elsevier Inc. All rights reserved.

Equivalent-Continuum Modeling With Application to Carbon Nanotubes

NASA Technical Reports Server (NTRS)

Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

2002-01-01

A method has been proposed for developing structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with equivalent-continuum models. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As important examples with direct application to the development and characterization of single-walled carbon nanotubes and the design of nanotube-based devices, the modeling technique has been applied to determine the effective-continuum geometry and bending rigidity of a graphene sheet. A representative volume element of the chemical structure of graphene has been substituted with equivalent-truss and equivalent continuum models. As a result, an effective thickness of the continuum model has been determined. This effective thickness has been shown to be significantly larger than the interatomic spacing of graphite. The effective thickness has been shown to be significantly larger than the inter-planar spacing of graphite. The effective bending rigidity of the equivalent-continuum model of a graphene sheet was determined by equating the vibrational potential energy of the molecular model of a graphene sheet subjected to cylindrical bending with the strain energy of an equivalent continuum plate subjected to cylindrical bending.

7 CFR 4280.153 - Substitution of lender.

Code of Federal Regulations, 2011 CFR

2011-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Renewable Energy Systems and Energy... section. (b) The Agency may approve the substitution of a new lender if the proposed substitute lender: (1...

7 CFR 4280.153 - Substitution of lender.

Code of Federal Regulations, 2010 CFR

2010-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Renewable Energy Systems and Energy... section. (b) The Agency may approve the substitution of a new lender if the proposed substitute lender: (1...

Energy balances of bioenergy crops (Miscanthus, maize, rapeseed) and their CO2-mitigation potential on a regional farm scale

NASA Astrophysics Data System (ADS)

Felten, D.; Emmerling, C.

2012-04-01

Increasing cultivation of energy crops in agriculture reveals the progressive substitution of fossil fuels, such as crude oil or brown coal. For the future development of renewable resources, the efficiency of different cropping systems will be crucial, as energy crops differ in terms of the energy needed for crop cultivation and refinement and the respective energy yield, e.g. per area. Here, balancing is certainly the most suitable method for the assessment of cropping system efficiency, contrasting energy inputs with energy outputs and the related CO2 emissions with potential CO2 credits due to substitution of fossil fuels, respectively. The aim of the present study was to calculate both energy and CO2 balances for rapeseed and maize, representing the recently most often cultivated energy crops in Germany, on a regional farm scale. Furthermore, special emphasis was made on perennial Miscanthus x giganteus, which is commonly used as a solid fuel for combustion. This C4-grass is of increasing interest due to its high yield potential accompanied by low requirements for soil tillage, weed control, and fertilization as well as long cultivation periods up to 25 years. In contrast to more general approaches, balances were calculated with local data from commercial farms. The site-specific consumption of diesel fuel was calculated using an online-based calculator, developed by the German Association for Technology and Structures in Agriculture (KTBL). By balancing each of the aforementioned cropping systems, our research focused on (i) the quantification of energy gains and CO2 savings due to fossil fuel substitution and (ii) the assessment of energy efficiency, expressed as the ratio of energy output to input. The energy input was highest for maize sites (33.8 GJ ha-1 yr-1), followed by rapeseed (18.2 GJ ha-1 yr-1), and Miscanthus (1.1 GJ ha-1 yr-1); corresponding energy yields were 129.5 GJ ha-1 yr-1 (maize), 83.6 GJ ha-1 yr-1 (rapeseed), and 259.7 GJ ha-1 yr-1 (Miscanthus), respectively. The energy output:input ratios were 3.83 (maize), 4.59 (rapeseed), and 236 (Miscanthus). The cultivation of rapeseed for biodiesel led to reduced CO2 emissions of 3.552 Mg ha-1 yr-1 due to substitution of diesel fuel. An amount of 9.312 Mg CO2 ha-1 yr-1 was saved by maize as co-ferment for biogas. Thereby, biogas was a substitute for electrical power from German energy mix (esp. nuclear power, utilization of coal), whereas the simultaneously used thermal energy was assumed to replace heating oil. Miscanthus cropping saved up to 18.540 Mg CO2 ha-1 yr-1 as a substitute for heating oil, including approx. 4 Mg CO2 ha-1 from organic carbon, which got sequestered within the soil organic matter due to site-remaining crop residues. In sum, each cropping system gained energy and reduced greenhouse gas emissions, although energy inputs and outputs differed significantly. High energy inputs for maize and rapeseed were mainly related to mineral N-fertilization. Also the need of methanol for biodiesel refining and the energy consumed by the biogas plant increased the total energy consumption markedly. Due to its low-input character, Miscanthus seems promising to fulfill several demands in the context of sustainability.

Equivalent-Continuum Modeling of Nano-Structured Materials

NASA Technical Reports Server (NTRS)

Odegard, Gregory M.; Gates, Thomas S.; Nicholson, Lee M.; Wise, Kristopher E.

2001-01-01

A method has been developed for modeling structure-property relationships of nano-structured materials. This method serves as a link between computational chemistry and solid mechanics by substituting discrete molecular structures with an equivalent-continuum model. It has been shown that this substitution may be accomplished by equating the vibrational potential energy of a nano-structured material with the strain energy of representative truss and continuum models. As an important example with direct application to the development and characterization of single-walled carbon nanotubes, the model has been applied to determine the effective continuum geometry of a graphene sheet. A representative volume element of the equivalent-continuum model has been developed with an effective thickness. This effective thickness has been shown to be similar to, but slightly smaller than, the interatomic spacing of graphite.

Comparison among methods of effective energy evaluation of corn silage for beef cattle.

PubMed

Wei, Ming; Chen, Zhiqiang; Wei, Shengjuan; Geng, Guangduo; Yan, Peishi

2018-06-01

This study was conducted to compare different methods on effective energy evaluation of corn silage for beef cattle. Twenty Wandong bulls (Chinese indigenous yellow cattle) with initial body weight of 281±15.6 kg, were assigned to 1 of 5 dietary treatments with 4 animals per treatment in a randomized complete block design. Five dietary treatments included group 1 with corn silage only diet, group 2 with corn silage-concentrate basal diet (BD) and 3 groups with 3 test diets, which were the BD partly substituted by corn silage at 10%, 30%, and 60%. The total collection digestion trial was conducted for 5 d for each block after a 10-d adaptation period, and then an open-circuit respiratory cage was used to measure the gas exchange of each animal in a consecutive 4-d period. The direct method-derived metabolizable energy and net energy of corn silage were 8.86 and 5.15 MJ/kg dry matter (DM), expressed as net energy requirement for maintenance and gain were 5.28 and 2.90 MJ/kg DM, respectively; the corresponding regression method-derived estimates were 8.96, 5.34, 5.37, and 2.98 MJ/kg DM, respectively. The direct method-derived estimates were not different (p>0.05) from those obtained using the regression method. Using substitution method, the nutrient apparent digestibility and effective energy values of corn silage varied with the increased corn silage substitution ratio (p<0.05). In addition, the corn silage estimates at the substitution ratio of 30% were similar to those estimated by direct and regression methods. In determining the energy value of corn silage using substitution method, there was a discrepancy between different substitution ratios, and the substitution ratio of 30% was more appropriate than 10% or 60% in the current study. The regression method based on multiple point substitution was more appropriate than single point substitution on energy evaluation of feedstuffs for beef cattle.

Life-cycle-assessment of the historical development of air pollution control and energy recovery in waste incineration.

PubMed

Damgaard, Anders; Riber, Christian; Fruergaard, Thilde; Hulgaard, Tore; Christensen, Thomas H

2010-07-01

Incineration of municipal solid waste is a debated waste management technology. In some countries it is the main waste management option whereas in other countries it has been disregarded. The main discussion point on waste incineration is the release of air emissions from the combustion of the waste, but also the energy recovery efficiency has a large importance. The historical development of air pollution control in waste incineration was studied through life-cycle-assessment modelling of eight different air pollution control technologies. The results showed a drastic reduction in the release of air emissions and consequently a significant reduction in the potential environmental impacts of waste incineration. Improvements of a factor 0.85-174 were obtained in the different impact potentials as technology developed from no emission control at all, to the best available emission control technologies of today (2010). The importance of efficient energy recovery was studied through seven different combinations of heat and electricity recovery, which were modelled to substitute energy produced from either coal or natural gas. The best air pollution control technology was used at the incinerator. It was found that when substituting coal based energy production total net savings were obtained in both the standard and toxic impact categories. However, if the substituted energy production was based on natural gas, only the most efficient recovery options yielded net savings with respect to the standard impacts. With regards to the toxic impact categories, emissions from the waste incineration process were always larger than those from the avoided energy production based on natural gas. The results shows that the potential environmental impacts from air emissions have decreased drastically during the last 35 years and that these impacts can be partly or fully offset by recovering energy which otherwise should have been produced from fossil fuels like coal or natural gas. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Assessing the greenhouse impact of natural gas

NASA Astrophysics Data System (ADS)

Cathles, L. M.

2012-06-01

The global warming impact of substituting natural gas for coal and oil is currently in debate. We address this question here by comparing the reduction of greenhouse warming that would result from substituting gas for coal and some oil to the reduction which could be achieved by instead substituting zero carbon energy sources. We show that substitution of natural gas reduces global warming by 40% of that which could be attained by the substitution of zero carbon energy sources. At methane leakage rates that are ˜1% of production, which is similar to today's probable leakage rate of ˜1.5% of production, the 40% benefit is realized as gas substitution occurs. For short transitions the leakage rate must be more than 10 to 15% of production for gas substitution not to reduce warming, and for longer transitions the leakage must be much greater. But even if the leakage was so high that the substitution was not of immediate benefit, the 40%-of-zero-carbon benefit would be realized shortly after methane emissions ceased because methane is removed quickly from the atmosphere whereas CO2 is not. The benefits of substitution are unaffected by heat exchange to the ocean. CO2 emissions are the key to anthropogenic climate change, and substituting gas reduces them by 40% of that possible by conversion to zero carbon energy sources. Gas substitution also reduces the rate at which zero carbon energy sources must eventually be introduced.

Food intake regulation in children. Fat and sugar substitutes and intake.

PubMed

Birch, L L; Fisher, J O

1997-05-23

A series of experiments exploring children's responsiveness to manipulations of energy density and macronutrient content of foods have been reviewed to assess the nutritional impact of macronutrient substitutes on children's intake. In these experiments, the focus is on the extent to which the energy content of foods was a salient factor influencing children's food intake, and macronutrient substitutes were used as tools to investigate this issue. Therefore, although several different macronutrient substitutes have been used in this research, we do not have a parametric set of experiments systematically assessing the impact of a variety of macronutrient substitutes. Given this, what can we conclude from the existing data? When the energy density and macronutrient content of foods is altered through the use of macronutrient substitutes that reduce the energy content of foods, children tend to adjust for the missing energy, although this adjustment may be partial and incomplete. This suggests the possibility that when macronutrient substitutes are used to reduce the energy content of foods, children's energy intake may be reduced. This adjustment, however, will most likely be less than a "calorie for calorie" reduction. In addition, even among young children, there are individual differences in the extent to which children adjust their intake in response to macronutrient and energy manipulations. The data are more extensive and particularly clear for cases in which CHO manipulations are used to alter energy density, but there is evidence for adjustments in energy intake in response to alterations of the fat content of the diet. The compensation for energy is not macronutrient specific; that is, when the fat content of food is reduced to reduce energy density of foods, children do not selectively consume fat in subsequent meals. This means that manipulations of macronutrient content of foods that reduce foods' energy content may not result in alterations of energy intake, but because these adjustments in energy intake are not macronutrient specific, changes in the overall macronutrient composition of children's diets can be obtained. There does not appear to be anything unique or special about the effects of macronutrient substitutes on children's intake; their effects are similar to those produced by other manipulations of macronutrient and energy content accomplished without macronutrient substitutes (e.g., augmenting foods with fat or carbohydrate to produce macronutrient differences). The research also indicates that under conditions that minimize adult attempts to control how much and what children eat, children can adjust their food and energy intake in response to the alterations of macronutrient and energy content of foods. Whether or not young children adjust food intake to compensate for energy-density changes depends upon their opportunity to control their own food intake as opposed to having their intake controlled by others. Young children's ability to adjust intake in response to alterations in the energy density of foods can be readily disrupted by the imposition of controlling child-feeding practices that attempt to regulate what and how much children eat. We believe that early experiences, including child-feeding practices imposed by parents, are major factors contributing to the etiology of individual differences and gender differences in the behavioral controls of food intake that can occur in response to the energy content of foods. The extent to which children respond to energy density of the diet has major implications for the effects of fat and sugar substitutes on children's intake. If children who are responsive to energy density consume substantial amounts of foods containing macronutrient substitutes, they should show some adjustments in intake to compensate for reduced energy, so that the impact of macronutrient substitutes on energy intake may be relatively small. However, changes in macronutrient com

Microwave implementation of two-source energy balance approach for estimating evapotranspiration

USDA-ARS?s Scientific Manuscript database

A newly developed microwave (MW) land surface temperature (LST) product is used to effectively substitute thermal infrared (TIR) based LST in the two-source energy balance approach (TSEB) for estimating ET from space. This TSEB land surface scheme, used in the Atmosphere Land Exchange Inverse (ALEXI...

Climate change mitigation effect of harvested wood products in regions of Japan.

PubMed

Kayo, Chihiro; Tsunetsugu, Yuko; Tonosaki, Mario

2015-12-01

Harvested wood products (HWPs) mitigate climate change through carbon storage, material substitution, and energy substitution. We construct a model to assess the overall climate change mitigation effect (comprising the carbon storage, material substitution, and energy substitution effects) resulting from HWPs in regions of Japan. The model allows for projections to 2050 based on future scenarios relating to the domestic forestry industry, HWP use, and energy use. Using the production approach, a nationwide maximum figure of 2.9 MtC year -1 for the HWP carbon storage effect is determined for 2030. The maximum nationwide material substitution effect is 2.9 MtC year -1 in 2050. For the energy substitution effect, a nationwide maximum projection of 4.3 MtC year -1 in 2050 is established, with at least 50 % of this figure derived from east and west Japan, where a large volume of logging residue is generated. For the overall climate change mitigation effect, a nationwide maximum projection of 8.4 MtC year -1 in 2050 is established, equivalent to 2.4 % of Japan's current carbon dioxide emissions. When domestic roundwood production and HWP usage is promoted, an overall climate change mitigation effect is consistently expected to be attributable to HWPs until 2050. A significant factor in obtaining the material substitution effect will be substituting non-wooden buildings with wooden ones. The policy of promoting the use of logging residue will have a significant impact on the energy substitution effect. An important future study is an integrated investigation of the climate change mitigation effect for both HWPs and forests.

Emissions and temperature benefits: The role of wind power in China

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

Duan, Hongbo, E-mail: hbduan@ucas.ac.cn

Background: As a non-fossil technology, wind power has an enormous advantage over coal because of its role in climate change mitigation. Therefore, it is important to investigate how substituting wind power for coal-fired electricity will affect emission reductions, changes in radiative forcing and rising temperatures, particularly in the context of emission limits. Methods: We developed an integrated methodology that includes two parts: an energy-economy-environmental (3E) integrated model and an emission-temperature response model. The former is used to simulate the dynamic relationships between economic output, wind energy and greenhouse gas (GHG) emissions; the latter is used to evaluate changes in radiativemore » forcing and warming. Results: Under the present development projection, wind energy cannot serve as a major force in curbing emissions, even under the strictest space-restraining scenario. China's temperature contribution to global warming will be up to 21.76% if warming is limited to 2 degrees. With the wind-for-coal power substitution, the corresponding contribution to global radiative forcing increase and temperature rise will decrease by up to 10% and 6.57%, respectively. Conclusions: Substituting wind power for coal-fired electricity has positive effects on emission reductions and warming control. However, wind energy alone is insufficient for climate change mitigation. It forms an important component of the renewable energy portfolio used to combat global warming. - Highlights: • We assess the warming benefits associated with substitution of wind power for coal. • The effect of emission space limits on climate responses is deeply examined. • China is responsible for at most 21.76% of global warming given the 2-degree target. • Wind power alone may not be sufficient to face the challenge of climate change. • A fertile policy soil and an aggressive plan are necessary to boost renewables.« less

Overview of a flywheel stack energy storage system

NASA Technical Reports Server (NTRS)

Kirk, James A.; Anand, Davinder K.

1988-01-01

The concept of storing electrical energy in rotating flywheels provides an attractive substitute to batteries. To realize these advantages the critical technologies of rotor design, composite materials, magnetic suspension, and high efficiency motor/generators are reviewed in this paper. The magnetically suspended flywheel energy storage system, currently under development at the University of Maryland, consisting of a family of interference assembled rings, is presented as an integrated solution for energy storage.

Economical and Energy Efficiency of Iron and Steel Industry Reindustrialisation in Russia Based on Implementation of Breakthrough Energy-Saving Technologies

NASA Astrophysics Data System (ADS)

Shevelev, L. N.

2017-12-01

Estimates were given of economical and energy efficiency of breakthrough energy-saving technologies, which increase competitive advantages and provide energy efficiency of production while reducing negative impact on the environment through reduction of emissions of harmful substances and greenhouse gases in the atmosphere. Among these technologies, preference is given to the following: pulverized coal fuel, blast-furnace gas recycling, gasification of non-coking coal in bubble-type gas-generators, iron-ore concentrate briquetting with steam coal with further use of ore-coal briquettes in electric furnace steel making. Implementation of these technologies at iron and steel works will significantly reduce the energy intensity of production through reduction of expensive coking coal consumption by means of their substitution by less expensive non-coking (steam) coal, and natural gas substitution by own secondary energy resource, which is the reducing gas. As the result, plants will get an opportunity to become self-sufficient in energy-resources and free themselves entirely from expensive purchased energy resources (natural gas, electric power, and partially coking coals), and cross over to low-carbon development.

Strategic factors of development of the enterprises

NASA Astrophysics Data System (ADS)

Ritman, Natali; Pimenova, Anna; Kuzmina, Svetlana; Baranova, Alla

2017-10-01

The complication of economic development of the Russian industry connected with changes in conditions of attraction of credit resources with certain difficulties of access to some foreign technologies and a number of types of goods results in need to consider tasks of import substitution and optimization of costs of production as priority in the combination. In this regard, measures for stimulation of development of industry are carried to number of the key directions of development of domestic economy by the state. Features of the transportation or energy company directly reflect and in an essential part define the main problems of functioning of producers. Insufficient competitiveness of the enterprises of some industry (for example transportation or energy company) of Russia in an essential measure is connected with the low level of finishing results of a scientific research and developments to a stage of the organization of production. In article authors consider the target directions and sources of development of production of the Russian Federation in the conditions of import substitution policy, and also represent results of the conducted research that has allowed to reveal features of factors of strategic development of the enterprise and to formulate the principles of strategic approach to development of the transportation or energy enterprises of industry.

First-principles study on alkali-metal effect of Li, Na, and K in CuInSe2 and CuGaSe2

NASA Astrophysics Data System (ADS)

Maeda, Tsuyoshi; Kawabata, Atsuhito; Wada, Takahiro

2015-08-01

The substitution energies and migration energies of the alkali metal atoms of Li, Na, and K in CuInSe2 (CIS) and CuGaSe2 (CGS) were investigated by first-principles calculations. The substitution energies of Li, Na, and K atoms in CIS and CGS were calculated for two different cationic atom positions of Cu and In/Ga in the chalcopyrite unit cell. In CIS and CGS, the substitution energies of NaCu are much lower than those of NaIn and NaGa. The substitution energies of the LiCu atoms in CIS and CGS are lower than those of NaCu, while the substitution energies of KCu atoms in CIS and CGS are much higher than those of NaCu. Therefore, it is difficult to form KCu in CIS and CGS. The migration energies of Li, Na, and K atoms in CIS and CGS are obtained by a combination of the linear and quadratic synchronous transit (LST/QST) methods and the nudged elastic band (NEB) method. The theoretical migration energies of a Na atom at the Cu site to the nearest Cu vacancy (NaCu → VCu) in CIS and CGS are much lower than those of (CuCu → VCu) in CIS and CGS. The mechanism underlying the alkali metal effect of Li, Na, and K in the CIGS film during the post-deposition treatment of LiF, NaF, and KF is discussed on the basis of the calculated substitution and migration energies.

Statistical Physics of Complex Substitutive Systems

NASA Astrophysics Data System (ADS)

Jin, Qing

Diffusion processes are central to human interactions. Despite extensive studies that span multiple disciplines, our knowledge is limited to spreading processes in non-substitutive systems. Yet, a considerable number of ideas, products, and behaviors spread by substitution; to adopt a new one, agents must give up an existing one. This captures the spread of scientific constructs--forcing scientists to choose, for example, a deterministic or probabilistic worldview, as well as the adoption of durable items, such as mobile phones, cars, or homes. In this dissertation, I develop a statistical physics framework to describe, quantify, and understand substitutive systems. By empirically exploring three collected high-resolution datasets pertaining to such systems, I build a mechanistic model describing substitutions, which not only analytically predicts the universal macroscopic phenomenon discovered in the collected datasets, but also accurately captures the trajectories of individual items in a complex substitutive system, demonstrating a high degree of regularity and universality in substitutive systems. I also discuss the origins and insights of the parameters in the substitution model and possible generalization form of the mathematical framework. The systematical study of substitutive systems presented in this dissertation could potentially guide the understanding and prediction of all spreading phenomena driven by substitutions, from electric cars to scientific paradigms, and from renewable energy to new healthy habits.

Bond Dissociation Energies for Substituted Polycyclic Aromatic Hydrocarbons and Their Cations

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W.; Langhoff, Stephen R.; Arnold, James O. (Technical Monitor)

1998-01-01

The B3LYP/4-31G approach is used to compute bond energies for a series of substituted benzene, naphthalene, and anthracene molecules and their cations. The benzene bond energies are compared with experiment. The trends in the bond energies are discussed. The ionization energies are also reported and compared with available experiments.

DISSOCIATIVE PHOTOIONIZATION OF POLYCYCLIC AROMATIC HYDROCARBON MOLECULES CARRYING AN ETHYNYL GROUP

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

Rouillé, G.; Krasnokutski, S. A.; Fulvio, D.

The life cycle of the population of interstellar polycyclic aromatic hydrocarbon (PAH) molecules depends partly on the photostability of the individual species. We have studied the dissociative photoionization of two ethynyl-substituted PAH species, namely, 9-ethynylphenanthrene and 1-ethynylpyrene. Their adiabatic ionization energy and the appearance energy of fragment ions have been measured with the photoelectron photoion coincidence spectroscopy technique. The adiabatic ionization energy has been found at 7.84 ± 0.02 eV for 9-ethynylphenanthrene and at 7.41 ± 0.02 eV for 1-ethynylpyrene. These values are similar to those determined for the corresponding non-substituted PAH molecules phenanthrene and pyrene. The appearance energy ofmore » the fragment ion indicative of the loss of a H atom following photoionization is also similar for either ethynyl-substituted PAH molecule and its non-substituted counterpart. The measurements are used to estimate the critical energy for the loss of a H atom by the PAH cations and the stability of ethynyl-substituted PAH molecules upon photoionization. We conclude that these PAH derivatives are as photostable as the non-substituted species in H i regions. If present in the interstellar medium, they may play an important role in the growth of interstellar PAH molecules.« less

High Energy Density Capacitors

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

None

2010-07-01

BEEST Project: Recapping is developing a capacitor that could rival the energy storage potential and price of today’s best EV batteries. When power is needed, the capacitor rapidly releases its stored energy, similar to lightning being discharged from a cloud. Capacitors are an ideal substitute for batteries if their energy storage capacity can be improved. Recapping is addressing storage capacity by experimenting with the material that separates the positive and negative electrodes of its capacitors. These separators could significantly improve the energy density of electrochemical devices.

Parameters and computer software for the evaluation of mass attenuation and mass energy-absorption coefficients for body tissues and substitutes.

PubMed

Okunade, Akintunde A

2007-07-01

The mass attenuation and energy-absorption coefficients (radiation interaction data), which are widely used in the shielding and dosimetry of X-rays used for medical diagnostic and orthovoltage therapeutic procedures, are strongly dependent on the energy of photons, elements and percentage by weight of elements in body tissues and substitutes. Significant disparities exist in the values of percentage by weight of elements reported in literature for body tissues and substitutes for individuals of different ages, genders and states of health. Often, interested parties are in need of these radiation interaction data for body tissues or substitutes with percentage by weight of elements and intermediate energies that are not tabulated in literature. To provide for the use of more precise values of these radiation interaction data, parameters and computer programs, MUA_T and MUEN_T are presented for the computation of mass attenuation and energy-absorption coefficients for body tissues and substitutes of arbitrary percentage-by-weight elemental composition and photon energy ranging between 1 keV (or k-edge) and 400 keV. Results are presented, which show that the values of mass attenuation and energy-absorption coefficients obtained from computer programs are in good agreement with those reported in literature.

The effect of substitution therapy on symptoms in patients with hypothyroidism following treatment for laryngeal and hypopharyngeal carcinomas.

PubMed

Lo Galbo, A M; Verdonck-De Leeuw, I M; Lips, P; Kuik, D J; Leemans, C R; De Bree, R

2013-08-01

Hypothyroidism is a well-known complication following treatment of laryngeal or hypopharyngeal carcinomas, and may cause various psychological and physical problems that negatively affect quality of life. The aim of this study was to evaluate the effect of substitution therapy on symptoms in patients with hypothyroidism. A study-specific questionnaire on physical and psychological problems (before and after substitution therapy) was sent to 70 patients who had been treated between 1977 and 2008 with clinical or subclinical hypothyroidism. Ninety-four percent returned the questionnaire. Symptoms on energy levels were reported most often (67% always tired and 70% lack of energy). Moodiness and emotional and physical symptoms were reported more often in substituted (sub)clinical hypothyroidism. Substitution therapy resulted in an improvement of energy (P = 0.013), sense of general interest and enjoyment (P = 0.022) and a reduction of puffy face (P = 0.041). Most symptoms in patients with thyroid dysfunction do not improve after substitution therapy. Nevertheless, due to its impact on health-related quality of life and the low burden of substitution therapy, screening for hypothyroidism and subsequent substitution therapy remains important.

PubMed Central

LO GALBO, A.M.; VERDONCK-DE LEEUW, I.M.; LIPS, P.; KUIK, D.J; LEEMANS, C.R.; DE BREE, R.

2013-01-01

SUMMARY Hypothyroidism is a well-known complication following treatment of laryngeal or hypopharyngeal carcinomas, and may cause various psychological and physical problems that negatively affect quality of life. The aim of this study was to evaluate the effect of substitution therapy on symptoms in patients with hypothyroidism. A study-specific questionnaire on physical and psychological problems (before and after substitution therapy) was sent to 70 patients who had been treated between 1977 and 2008 with clinical or subclinical hypothyroidism. Ninety-four percent returned the questionnaire. Symptoms on energy levels were reported most often (67% always tired and 70% lack of energy). Moodiness and emotional and physical symptoms were reported more often in substituted (sub)clinical hypothyroidism. Substitution therapy resulted in an improvement of energy (P = 0.013), sense of general interest and enjoyment (P = 0.022) and a reduction of puffy face (P = 0.041). Most symptoms in patients with thyroid dysfunction do not improve after substitution therapy. Nevertheless, due to its impact on health-related quality of life and the low burden of substitution therapy, screening for hypothyroidism and subsequent substitution therapy remains important. PMID:24043910

CNRS interdisciplinary research program for solar energy development

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

Not Available

The contributions of CNRS to the French national solar energy R and D program are reviewed. The three principal processes in which solar radiation is converted into other, directly usable energy forms are discussed in detail. These include thermodynamic conversion, photovoltaic conversion, and bioconversion to produce a substitute fuel. Related research on insolation and the weather is mentioned and relations with the industrial sector are considered. French collaboration with other countries in solar energy is discussed.

Energy prices and substitution in United States manufacturing plants

NASA Astrophysics Data System (ADS)

Grim, Cheryl

Persistent regional disparities in electricity prices, growth in wholesale power markets, and recent deregulation attempts have intensified interest in the performance of the U.S. electric power industry, while skyrocketing fuel prices have brought renewed interest in the effect of changes in prices of all energy types on the U.S. economy. This dissertation examines energy prices and substitution between energy types in U.S. manufacturing. I use a newly constructed database that includes information on purchased electricity and electricity expenditures for more than 48,000 plants per year and additional data on the utilities that supply electricity to study the distribution of electricity prices paid by U.S. manufacturing plants from 1963 to 2000. I find a large compression in the dispersion of electricity prices from 1963 to 1978 due primarily to a decrease in quantity discounts for large electricity purchasers. I also find that spatial dispersion in retail electricity prices among states, counties and utility service territories is large, rises over time for smaller purchasers, and does not diminish as wholesale power markets expand in the 1990s. In addition, I examine energy type consumption patterns, prices, and substitution in U.S. manufacturing plants. I develop a plant-level dataset for 1998 with data on consumption and expenditures on energy and non-energy production inputs, output, and other plant characteristics. I find energy type consumption patterns vary widely across manufacturing plants. Further, I find a large amount of dispersion across plants in the prices paid for electricity, oil, natural gas, and coal. These high levels of dispersion are accounted for by the plant's location, industry, and purchase quantity. Finally, I present estimates of own- and cross-price elasticities of demand for both the energy and non-energy production inputs.

Solvolysis of para-substituted cumyl chlorides. Brown and Okamoto's electrophilic substituent constants revisited using continuum solvent models.

PubMed

DiLabio, Gino A; Ingold, K U

2004-03-05

Brown and Okamoto (J. Am. Chem. Soc. 1958, 80, 4979) derived their electrophilic substitutent constants, sigma(p)+, from the relative rates of solvolysis of ring-substituted cumyl chlorides in an acetone/water solvent mixture. Application of the Hammett equation to the rates for the meta-substituted cumyl chlorides, where there could be no resonance interaction with the developing carbocation, gave a slope, rho(+) = -4.54 ( identical with 6.2 kcal/mol free energy). Rates for the para-substituted chlorides were then used to obtain sigma(p)+ values. We have calculated gas-phase C-Cl heterolytic bond dissociation enthalpy differences, Delta BDE(het) (= BDE(het)(4-YC(6)H(4)CMe(2)Cl) - BDE(het)(C(6)H(5)CMe(2)Cl)), for 16 of the 4-Y substituents employed by Brown and Okamoto. The plot of Delta BDE(het) vs sigma(p)+ gave rho(+) (SD) = 16.3 (2.3) kcal/mol, i.e., a rho(+) value roughly 2.5 times greater than experiment. Inclusion of solvation (water) energies, calculated using three continuum solvent models, reduced rho(+) and SD. The computationally least expensive model used, SM5.42R (Li et al. Theor. Chem. Acc. 1999, 103, 9) gave the best agreement with experiment. This model yielded rho(+) (SD) = 7.7 (0.9) kcal/mol, i.e., a rho(+) value that is only 24% larger than experiment.

Transformation of cooperative free energies between ligation systems of hemoglobin: resolution of the carbon monoxide binding intermediates.

PubMed

Huang, Y; Ackers, G K

1996-01-23

A strategy has been developed for quantitatively "translating" the distributions of cooperative free energy between different oxygenation analogs of hemoglobin (Hb). The method was used to resolve the cooperative free energies of all eight carbon monoxide binding intermediates. These parameters of the FeCOHb system were determined by thermodynamic transformation of corresponding free energies obtained previously for all species of the Co/FeCO system, i.e., where cobalt-substituted hemes comprise the unligated sites [Speros, P. C., et al. (1991) Biochemistry 30, 7254-7262]. Using hybridized combinations of normal and cobalt-substituted Hb, ligation analog systems Co/FeX (X = CO, CN) were constructed and experimentally quantified. Energetics of cobalt-induced structural perturbation were determined for all species of both the "mixed metal" Co/Fe system and also the ligated Co/FeCN system. It was found that major energetic perturbations of the Co/Fe hybrid species originate from a pure cobalt substitution effect on the alpha subunits. These perturbations are transduced to the beta subunit within the same dimeric half-tetramer, resulting in alteration of the free energies for binding at the nonsubstituted (Fe) sites. Using the linkage strategy developed in this study along with the determined energetics of these couplings, the experimental assembly free energies for the Co/FeCO species were transformed into cooperative free energies of the 10 Fe/FeCO species. The resulting values were found to distribute according to predictions of a symmetry rule mechanism proposed previously [Ackers, G. K., et al. (1992) Science 255, 54-63]. Their distribution is consistent with accurate CO binding data of normal Hb [Perrella, M., et al. (1990b) Biophys. Chem. 37, 211-223] and also with accurate O2 binding data obtained under the same conditions [Chu, A. H., et al. (1984) Biochemistry 23, 604-617].

Mitochondrial ATPase Subunit 6 and Cytochrome B Gene Variations in Obese Turkish Children

PubMed Central

Demir, Durkadın; Türkkahraman, Doğa; Samur, Anıl Aktaş; Lüleci, Güven; Akçurin, Sema; M. Alper, Özgül

2014-01-01

Objective: Due to the importance of energy metabolism in mitochondria, mitochondrial genome variations are evaluated in energy-related diseases such as obesity. To date, several nuclear genes were found to be related to obesity. Our aim in this study was to investigate the presence of polymorphisms in mitochondrial ATPase subunit 6 (mt-ATP6) and cytochrome b (mt-CytB) genes that may be associated with childhood obesity. Methods: The mt-ATP6 and mt-CytB genes were amplified and entirely sequenced in a series of 100 obese and in an equal number of healthy Turkish children aged between 6-14 years. Results: A total of 118 synonymous and nonsynonymous variations were detected in the obese and control groups. Only two previously reported synonymous substitutions (mt.8614T>C and mt.8994G>A) in the mt-ATP6 gene were found to be significantly higher in the obese group compared to the control group (p<0.05). In the mt-ATP6 gene, one novel nonsynonymous substitution (mt.8726C>T) and one novel synonymous substitution (mt.9108A>T) were found. In the mt-CytB gene, one nonsynonymous substitution (mt.14880T>C) and two synonymous substitutions (mt.14891C>T and mt.15091C>T) were novel substitutions. Conclusion: Two synonymous substitutions (mt.8614T>C and mt.8994G>A) in the mt-ATP6 gene may be associated with childhood obesity. Our study provides the first data about mitochondrial genome variations in a Turkish obese population and also the first in obese children. More cases should be screened in obese groups in order to understand the effects of mitochondrial polymorphisms in the development of obesity. PMID:25541891

Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 Magnets Sm2Fe17X3 (X =C , N) by Substituting La or Ce for Sm

NASA Astrophysics Data System (ADS)

Pandey, Tribhuwan; Du, Mao-Hua; Parker, David S.

2018-03-01

Designing a permanent magnet with reduced critical rare-earth content is of paramount importance in the development of cost-effective modern technologies. By performing comprehensive first-principles calculations, we investigate the potential avenues for reducing the critical rare-earth content in Sm2Fe17N3 and Sm2Fe17C3 by making a La or Ce substitution for Sm. The calculated magnetic properties of base compounds are in good agreement with the previous low-temperature (4.2-K) experimental measurements, and they show a large axial anisotropy. Although La or Ce substitution results in a slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostly remain unchanged. Specifically, large axial anisotropies of 7.2 and 4.1 MJ /m3 are obtained for SmCeFe17 N3 and SmLaFe17 N3 , respectively. These values of anisotropies are comparable to the state-of-the-art permanent magnet Nd2 Fe14 B . The foremost limitation of Sm2 Fe17X3 magnets for practical application is the formation nitrogen or carbon vacancies at high temperatures. By calculating the N- (C)- vacancy formation energy, we show that La or Ce substitution enhances the vacancy formation energy. This enhanced vacancy formation energy will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La- or Ce-substituted Sm2Fe17C3 and Sm2Fe17N3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare-earth content.

Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 Magnets Sm 2Fe 17X 3 (X=C, N) by Substituting La or Ce for Sm

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

Pandey, Tribhuwan; Du, Mao-Hua; Parker, David S.

Designing a permanent magnet with reduced critical rare-earth content is of paramount importance in the development of cost-effective modern technologies. By performing comprehensive first-principles calculations, we investigate the potential avenues for reducing the critical rare-earth content in Sm 2Fe 17N 3 and Sm 2Fe 17C 3 by making a La or Ce substitution for Sm. The calculated magnetic properties of base compounds are in good agreement with the previous low-temperature (4.2-K) experimental measurements, and they show a large axial anisotropy. Although La or Ce substitution results in a slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostlymore » remain unchanged. Specifically, large axial anisotropies of 7.2 and 4.1 MJ/m 3 are obtained for SmCeFe 17N 3 and SmLaFe 17N 3, respectively. These values of anisotropies are comparable to the state-of-the-art permanent magnet Nd 2Fe 14B. The foremost limitation of Sm 2Fe 17X 3 magnets for practical application is the formation nitrogen or carbon vacancies at high temperatures. By calculating the N- (C)- vacancy formation energy, we show that La or Ce substitution enhances the vacancy formation energy. Here, this enhanced vacancy formation energy will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La- or Ce-substituted Sm 2Fe 17C 3 and Sm 2Fe 17N 3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare-earth content.« less

Tuning the Magnetic Properties and Structural Stabilities of the 2-17-3 Magnets Sm 2Fe 17X 3 (X=C, N) by Substituting La or Ce for Sm

DOE PAGES

Pandey, Tribhuwan; Du, Mao-Hua; Parker, David S.

2018-03-05

Designing a permanent magnet with reduced critical rare-earth content is of paramount importance in the development of cost-effective modern technologies. By performing comprehensive first-principles calculations, we investigate the potential avenues for reducing the critical rare-earth content in Sm 2Fe 17N 3 and Sm 2Fe 17C 3 by making a La or Ce substitution for Sm. The calculated magnetic properties of base compounds are in good agreement with the previous low-temperature (4.2-K) experimental measurements, and they show a large axial anisotropy. Although La or Ce substitution results in a slight reduction of magnetic anisotropy, the magnetic moments of Fe atoms mostlymore » remain unchanged. Specifically, large axial anisotropies of 7.2 and 4.1 MJ/m 3 are obtained for SmCeFe 17N 3 and SmLaFe 17N 3, respectively. These values of anisotropies are comparable to the state-of-the-art permanent magnet Nd 2Fe 14B. The foremost limitation of Sm 2Fe 17X 3 magnets for practical application is the formation nitrogen or carbon vacancies at high temperatures. By calculating the N- (C)- vacancy formation energy, we show that La or Ce substitution enhances the vacancy formation energy. Here, this enhanced vacancy formation energy will likely improve the thermodynamic stability of these alloys at high temperatures. Therefore, La- or Ce-substituted Sm 2Fe 17C 3 and Sm 2Fe 17N 3 compounds are promising candidates for high-performance permanent magnets with substantially reduced rare-earth content.« less

Empowerment model of biomass in west java

NASA Astrophysics Data System (ADS)

Mulyana, C.; Fitriani, N. I.; Saad, A.; Yuliah, Y.

2017-06-01

Scarcity of fossil energy accelerates the search of renewable energy sources as the substitution. In West Java, biomass has potential to be developed into bio-briquette because the resources are abundant. The objectives of this research are mapping the potency of biomass as bio-briquette in West Java, and making the model of the empowerment biomass potential involving five fundamental step which are raw material, pre-processing process, conversion mechanism, products, and end user. The main object of this model focused on 3 forms which are solid, liquid, and gas which was made by involving the community component as the owner biomass, district government, academics and researcher communities, related industries as users of biomass, and the central government as the policy holders and investors as a funder. In the model was described their respective roles and mutual relationship one with another so that the bio-briquette as a substitute of fossil fuels can be realized. Application of this model will provide the benefits in renewability energy sources, environmental, socio economical and energy security.

The Energy of Substituted Ethanes. Asymmetry Orbitals

PubMed Central

Salem, Lionel; Hoffmann, Roald; Otto, Peter

1973-01-01

The leading terms in the energy of a general substituted ethane are derived in explicit form as a function of the torsional angle θ, the substituent electronegativities, and their mutual overlaps. The energy is found to be the sum of all four overlaps between pairs of asymmetry orbitals, and satisfies the requisite symmetry properties. PMID:16592060

Association of Dietary Proportions of Macronutrients with Visceral Adiposity Index: Non-Substitution and Iso-Energetic Substitution Models in a Prospective Study.

PubMed

Moslehi, Nazanin; Ehsani, Behnaz; Mirmiran, Parvin; Hojjat, Parvane; Azizi, Fereidoun

2015-10-26

We aimed to investigate associations between dietary macronutrient proportions and prospective visceral adiposity index changes (ΔVAI). The study included 1254 adults (18-74 years), from the Tehran Lipid and Glucose Study (TLGS), who were followed for three years. Dietary intakes were assessed twice using food frequency questionnaires. Associations of dietary macronutrient with ΔVAI and risk of visceral adiposity dysfunction (VAD) after three years were investigated. The percentage of energy intake from protein in the total population, and from fat in women, were associated with higher increases in VAI. A 5% higher energy intake from protein substituted for carbohydrate, monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs) was associated with higher ΔVAI. Higher energy intake from animal protein substituted for PUFAs was positively associated with ΔVAI. Substituting protein and PUFAs with MUFAs were related to higher ΔVAI. The associations were similar in men and women, but reached significance mostly among women. Risk of VAD was increased when 1% of energy from protein was replaced with MUFAs. Substituting protein for carbohydrate and fat, and fat for carbohydrate, resulted in increased risk of VAD in women. Higher dietary proportions of protein and animal-derived MUFA may be positively associated with ΔVAI and risk of VAD.

Density functional theory study of hydrogen atom abstraction from a series of para-substituted phenols: why is the Hammett σ(p)+ constant able to represent radical reaction rates?

PubMed

Yoshida, Tatsusada; Hirozumi, Koji; Harada, Masataka; Hitaoka, Seiji; Chuman, Hiroshi

2011-06-03

The rate of hydrogen atom abstraction from phenolic compounds by a radical is known to be often linear with the Hammett substitution constant σ(+), defined using the S(N)1 solvolysis rates of substituted cumyl chlorides. Nevertheless, a physicochemical reason for the above "empirical fact" has not been fully revealed. The transition states of complexes between the 2,2-diphenyl-1-picrylhydrazyl radical (dpph·) and a series of para-substituted phenols were determined by DFT (Density Functional Theory) calculations, and then the activation energy as well as the homolytic bond dissociation energy of the O-H bond and charge distribution in the transition state were calculated. The heterolytic bond dissociation energy of the C-Cl bond and charge distribution in the corresponding para-substituted cumyl chlorides were calculated in parallel. Excellent correlations among σ(+), charge distribution, and activation and bond dissociation energies revealed quantitatively that there is a strong similarity between the two reactions, showing that the electron-deficiency of the π-electron system conjugated with a substituent plays a crucial role in determining rates of the two reactions. The results provide a new insight into and physicochemical understanding of σ(+) in the hydrogen abstraction from substituted phenols by a radical.

On the use of Lineal Energy Measurements to Estimate Linear Energy Transfer Spectra

NASA Technical Reports Server (NTRS)

Adams, David A.; Howell, Leonard W., Jr.; Adam, James H., Jr.

2007-01-01

This paper examines the error resulting from using a lineal energy spectrum to represent a linear energy transfer spectrum for applications in the space radiation environment. Lineal energy and linear energy transfer spectra are compared in three diverse but typical space radiation environments. Different detector geometries are also studied to determine how they affect the error. LET spectra are typically used to compute dose equivalent for radiation hazard estimation and single event effect rates to estimate radiation effects on electronics. The errors in the estimations of dose equivalent and single event rates that result from substituting lineal energy spectra for linear energy spectra are examined. It is found that this substitution has little effect on dose equivalent estimates in interplanetary quiet-time environment regardless of detector shape. The substitution has more of an effect when the environment is dominated by solar energetic particles or trapped radiation, but even then the errors are minor especially if a spherical detector is used. For single event estimation, the effect of the substitution can be large if the threshold for the single event effect is near where the linear energy spectrum drops suddenly. It is judged that single event rate estimates made from lineal energy spectra are unreliable and the use of lineal energy spectra for single event rate estimation should be avoided.

Substituting whole grains for refined grains in a 6-week randomized trial favorably affects energy balance parameters in healthy men and post-menopausal women

USDA-ARS?s Scientific Manuscript database

Background: The effect of whole grains on the regulation of energy balance remains controversial. Objective: To determine the effects of substituting whole grains for refined grains, independent of body weight change, on energy metabolism parameters and glycemic control. Design: A randomized, con...

Data on development of new energy technologies

NASA Astrophysics Data System (ADS)

1994-03-01

The paper compiles data on the trend of development of new energy technologies into a book. By category, renewable energy is solar energy, wind power generation, geothermal power generation, ocean energy, and biomass. As a category of fuel form conversion, cited are coal liquefaction/gasification, coal gasification combined cycle power generation, and natural gas liquefaction/decarbonization. The other categories are cogeneration by fuel cell and ceramic gas turbine, district heat supply system, power load leveling technology, transportation-use substitution-fuel vehicle, and others (Stirling engine, superconducting power generator, etc.). The data are systematically compiled on essential principles, transition of introduction, objectives of introduction, status of production, cost, development schedule, performance, etc. The paper also deals with the related legislation system, developmental organizations, and a menu for power companies' buying surplus power.

General equilibrium effects of a supply side GHG mitigation option under the Clean Development Mechanism.

PubMed

Timilsina, Govinda R; Shrestha, Ram M

2006-09-01

The Clean Development Mechanism (CDM) under the Kyoto Protocol to the United Nations Framework Convention on Climate Change is considered a key instrument to encourage developing countries' participation in the mitigation of global climate change. Reduction of greenhouse gas (GHG) emissions through the energy supply and demand side activities are the main options to be implemented under the CDM. This paper analyses the general equilibrium effects of a supply side GHG mitigation option-the substitution of thermal power with hydropower--in Thailand under the CDM. A static multi-sector general equilibrium model has been developed for the purpose of this study. The key finding of the study is that the substitution of electricity generation from thermal power plants with that from hydropower plants would increase economic welfare in Thailand. The supply side option would, however, adversely affect the gross domestic product (GDP) and the trade balance. The percentage changes in economic welfare, GDP and trade balance increase with the level of substitution and the price of certified emission reduction (CER) units.

Substituent Effects in the Benzene Dimer are Due to Direct Interactions of the Substituents with the Unsubstituted Benzene

PubMed Central

Wheeler, Steven E.; Houk, K. N.

2009-01-01

The prevailing views of substituent effects in the sandwich configuration of the benzene dimer are flawed. For example, in the polar/π model of Cozzi and co-workers (J. Am. Chem. Soc. 1992, 114, 5729), electron-withdrawing substituents enhance binding in the benzene dimer by withdrawing electron density from the π-cloud of the substituted ring, reducing the repulsive electrostatic interaction with the non-substituted benzene. Conversely, electron-donating substituents donate excess electrons into the π-system and diminish the π-stacking interaction. We present computed interaction energies for the sandwich configuration of the benzene dimer and 24 substituted dimers, as well as sandwich complexes of substituted benzenes with perfluorobenzene. While the computed interaction energies correlate well with σm values for the substituents, interaction energies for related model systems demonstrate that this trend is independent of the substituted ring. Instead, the observed trends are consistent with direct electrostatic and dispersive interactions of the substituents with the unsubstituted ring. PMID:18652453

Accelerated hydrolysis of substituted cellulose for potential biofuel production: kinetic study and modeling.

PubMed

Mu, Bingnan; Xu, Helan; Yang, Yiqi

2015-11-01

In this work, kinetics of substitution accelerated cellulose hydrolysis with multiple reaction stages was investigated to lay foundation for mechanism study and molecular design of substituting compounds. High-efficiency hydrolysis of cellulose is critical for cellulose-based bioethanol production. It is known that, substitution could substantially decrease activation energy and increase reaction rate of acidic hydrolysis of glycosidic bonds in cellulose. However, reaction kinetics and mechanism of the accelerated hydrolysis were not fully revealed. In this research, it was proved that substitution therefore accelerated hydrolysis only occurred in amorphous regions of cellulose fibers, and was a process with multiple reaction stages. With molar ratio of substitution less than 1%, the overall hydrolysis rate could be increased for around 10 times. We also quantified the relationship between the hydrolysis rate of individual reaction stage and its major influences, including molar ratio of substitution, activation energy of acidic hydrolysis, pH and temperature. Copyright © 2015 Elsevier Ltd. All rights reserved.

Estimation of Free Radical Ionization Energies by the Kinetic Method and the Relationship between the Kinetic Method and the Hammett Equation.

PubMed

Chen, G; Wong, P; Cooks, R G

1997-09-01

Substituted 1,2-diphenylethanes undergo competitive dissociations upon electron ionization (EI) to generate substituted benzyl cation and benzyl radical pairs. Application of the kinetic method to the previous reported EI mass spectra of these covalently bound precursor ions (data are taken from McLafferty et al. J. Am. Chem. Soc. 1970, 92, 6867)) is used to estimate the ionization energies of substituted benzyl free radicals. A correlation is observed between the Hammett σ constant of the substituents and the kinetic method parameter, ln(k(x)/k(H)), where k(x) is the rate of fragmentation to give the substituted product ion and k(H) is the rate to give the benzyl ion itself. Systems involving weakly bound cluster ions, including proton-bound dimers of meta- and para-substituted pyridines and meta- and para-substituted anilines, and electron-bound dimers of meta- and para-substituted nitrobenzenes, also show good correlations between the kinetic method parameter and the Hammett σ constant.

Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy

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

D'Amours, Guillaume; Rahem, Ahmed; Mayer, Robert

2007-05-17

The motivation to reduce overall vehicle weight within the automotive sector drives the substitution of lightweight materials such as aluminium alloys for structural components. Such a substitution requires a significant amount of development to manufacture structurally parts such that the energy absorption characteristics are not sacrificed in the event of crash. The effects of the manufacturing processes on the crash performance of automotive structural components must be better understood to ensure improved crashworthiness. This paper presents results of an experimental and numerical investigation of the crash response and energy absorption properties of impacted hydroformed aluminium alloy tubes. Crash experiments onmore » hydroformed tubes were performed using a deceleration sled test at the General Motors Technical Center. Results from axial crush testing showed that an important parameter that influences the energy absorption characteristics during crash was the thickness reduction caused by circumferential expansion of the tube during hydroforming. It was found that that the energy absorption decreased as the corner radius decreased, which results because of increased thinning. Sensitivity studies of end feeding parameters, such as end feed level and profile, were carried out to evaluate their impact on the energy absorption of the aluminium tubes.« less

Crashworthiness of Aluminium Tubes; Part 2: Improvement of Hydroforming Operation to Increase Absorption Energy

NASA Astrophysics Data System (ADS)

D'Amours, Guillaume; Rahem, Ahmed; Mayer, Robert; Williams, Bruce; Worswick, Michael

2007-05-01

The motivation to reduce overall vehicle weight within the automotive sector drives the substitution of lightweight materials such as aluminium alloys for structural components. Such a substitution requires a significant amount of development to manufacture structurally parts such that the energy absorption characteristics are not sacrificed in the event of crash. The effects of the manufacturing processes on the crash performance of automotive structural components must be better understood to ensure improved crashworthiness. This paper presents results of an experimental and numerical investigation of the crash response and energy absorption properties of impacted hydroformed aluminium alloy tubes. Crash experiments on hydroformed tubes were performed using a deceleration sled test at the General Motors Technical Center. Results from axial crush testing showed that an important parameter that influences the energy absorption characteristics during crash was the thickness reduction caused by circumferential expansion of the tube during hydroforming. It was found that that the energy absorption decreased as the corner radius decreased, which results because of increased thinning. Sensitivity studies of end feeding parameters, such as end feed level and profile, were carried out to evaluate their impact on the energy absorption of the aluminium tubes.

Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with Nonlinear Quantum Corrections

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

Wang, Lei; Jakowski, Jacek; Garashchuk, Sophya

The experimentally observed effect of selective deuterium substitution on the open circuit voltage for a blend of poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C 61- butyric acid methyl ester (PCBM) (Nat. Commun. 5:3180, 2014) is explored using a 221-atom model of a polymer-wrapped PCBM molecule. We describe the protonic and deuteronic wavefunctions for the H/D isotopologues of the hexyl side chains within a Quantum Trajectory/Electronic Structure approach where the dynamics is performed with newly developed nonlinear corrections to the quantum forces, necessary to describe the nuclear wavefunctions; the classical forces are generated with a Density Functional Tight Binding method. We used the resulting protonicmore » and deuteronic time-dependent wavefunctions to assess the effects of isotopic substitution (deuteration) on the energy gaps relevant to the charge transfer for the donor and acceptor electronic states. Furthermore, while the isotope effect on the electronic energy levels is found negligible, the quantum-induced fluctuations of the energy gap between the charge transfer and charge separated states due to nuclear wavefunctions may account for experimental trends by promoting charge transfer in P3HT/PCBM and increasing charge recombination on the donor in the deuterium substituted P3HT/PCBM.« less

Understanding How Isotopes Affect Charge Transfer in P3HT/PCBM: A Quantum Trajectory-Electronic Structure Study with Nonlinear Quantum Corrections

DOE PAGES

Wang, Lei; Jakowski, Jacek; Garashchuk, Sophya; ...

2016-08-09

The experimentally observed effect of selective deuterium substitution on the open circuit voltage for a blend of poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl-C 61- butyric acid methyl ester (PCBM) (Nat. Commun. 5:3180, 2014) is explored using a 221-atom model of a polymer-wrapped PCBM molecule. We describe the protonic and deuteronic wavefunctions for the H/D isotopologues of the hexyl side chains within a Quantum Trajectory/Electronic Structure approach where the dynamics is performed with newly developed nonlinear corrections to the quantum forces, necessary to describe the nuclear wavefunctions; the classical forces are generated with a Density Functional Tight Binding method. We used the resulting protonicmore » and deuteronic time-dependent wavefunctions to assess the effects of isotopic substitution (deuteration) on the energy gaps relevant to the charge transfer for the donor and acceptor electronic states. Furthermore, while the isotope effect on the electronic energy levels is found negligible, the quantum-induced fluctuations of the energy gap between the charge transfer and charge separated states due to nuclear wavefunctions may account for experimental trends by promoting charge transfer in P3HT/PCBM and increasing charge recombination on the donor in the deuterium substituted P3HT/PCBM.« less

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

Carpenter, Alberta; Mann, Margaret; Gelman, Rachel

In evaluating next-generation materials and processes, the supply chain can have a large impact on the life cycle energy impacts. The Materials Flow through Industry (MFI) tool was developed for the Department of Energy's Advanced Manufacturing Office to be able to evaluate the energy impacts of the U.S. supply chain. The tool allows users to perform process comparisons, material substitutions, and grid modifications, and to see the effects of implementing sector efficiency potentials (Masanet, et al. 2009). This paper reviews the methodology of the tool and provides results around specific scenarios.

Comparative evaluation of solar, fission, fusion, and fossil energy resources. Part 5: Conclusions and recomendations

NASA Technical Reports Server (NTRS)

Williams, J. R.

1974-01-01

Air pollution resulting from the use of fossil fuels is discussed. Phenomena relating to the emission of CO2 such as the greenhouse effect and multiplier effect are explored. Particulate release is also discussed. The following recommendations are made for the elimination of fossil fuel combustion products in the United States: development of nuclear breeder reactors, use of solar energy systems, exploration of energy alternatives such as geothermal and fusion, and the substitution of coal for gas and oil use.

First-principles study on stability of transition metal solutes in aluminum by analyzing the underlying forces

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

Liu, Wei; Xu, Yichun; Li, Xiangyan

2015-05-07

Although there have been some investigations on behaviors of solutes in metals under strain, the underlying mechanism of how strain changes the stability of a solute is still unknown. To gain such knowledge, first-principles calculations are performed on substitution energy of transition metal solutes in fcc Al host under rhombohedral strain (RS). Our results show that under RS, substitution energy decreases linearly with the increase of outermost d radius r{sub d} of the solute due to Pauli repulsion. The screened Coulomb interaction increases or decreases the substitution energy of a solute on condition that its Pauling electronegativity scale ϕ{sub P}more » is less or greater than that of Al under RS. This paper verifies a linear relation of substitution energy change versus r{sub d} and ϕ{sub P} under RS, which might be instructive for composition design of long life alloys serving in high stress condition.« less

Quinone Photoreactivity: An Undergraduate Experiment in Photochemistry

ERIC Educational Resources Information Center

Vaughan, Pamela P.; Cochran, Michael; Haubrich, Nicole

2010-01-01

An experiment exploring the photochemical properties of quinones was developed. Their unique photochemistry and highly reactive nature make them an ideal class of compounds for examining structure-activity relationships. For several substituted quinones, photochemical reactivity was related to structure and ultimately to the Gibbs energy for…

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

Jones, D.W.

This paper identifies a number of developments which are prominent during the urbanization of a country and which have particularly strong implications for energy use. Concomitant with urbanization, the industrial composition of the economy's production shifts, with reductions in agriculture and increases in the importance of primary metals, chemicals, and cement, all of which are relatively energy-intensive sectors. Evidence from India indicates that the movement of a worker from agriculture to the least energy-intensive urban activity other than services will quadruple per worker production energy requirements. Next, population concentration associated with urbanization facilitates increases in the scale of production whichmore » in turn encourages the substitution of modern energy for traditional fuels and requires energy for longer deliveries. Also, concentrated, off-farm populations require processing and delivery of food, which are not required for largely agricultural countries. Domestic activity changes send activities which were formerly conducted in the household with little or no energy use, outside, usually into firms, where fuels are used. Urban households also use considerably more transportation than do rural households. Evidence from Hong Kong indicates that pure urban density increases encourage substitutions of modern energy for traditional fuels. Finally, increased real incomes associated with urbanization increase energy consumption, with an elasticity of roughly unity. Aggregate cross-sectional data evidence from sixty developing countries was used to examine the overall magnitude of the effects of urbanization and associated developmental changes on per capita energy use. Controlling for industrial structure, per capita income (per capita gross domestic product), and several other variables, a one-percent increase in urbanization will cause a one-half percent increase in per capita energy use. 81 refs., 5 figs., 63 tabs.« less

Forest Resources: An Overview

ERIC Educational Resources Information Center

Bethel, J. S.; Schreuder, G. F.

1976-01-01

Concern for long-term availability of nonrenewable resources has fostered proposals for substitution with renewable resources. Forest products could become the basis for materials substitution and production. Further feasibility studies are needed to determine the technical, economic, energy, and environmental aspects of substitution. (MR)

Economics and Environmental Compatibility of Fusion Reactors —Its Analysis and Coming Issues— 1.Energy Strategy of the 21st Century Taking Advantage of Fusion

NASA Astrophysics Data System (ADS)

Okumura, Norihiro

There is some general concern that economic development in developing countries will hasten global warning. In terms of reducing CO2 emissions, fusion will have great potential as a primary energy in the late 21st century according to the results of WING model simulations based on scenario analysis, if the cost of fusion with hydrogen generation would become competitive compared with those of other substitutive energies. However, securing social acceptance is very important to maintain the fossil research funded by the government suffering from cumulative debt.

Substituting telecommunications for travel - Feasible or desirable

NASA Technical Reports Server (NTRS)

Van Vleck, E. M.

1974-01-01

This paper reviews recent advances in telecommunications and examines the detailed structure of travel to estimate the feasibility of substituting telecommunications for various travel objectives. The impact of travel is analyzed from a social, economic, energy, and pollution standpoint to assess the desirability of substitution. Perhaps 35-50% of the nation's travel could, in theory, be replaced by very advanced telecommunications (such as a much improved large-screen teleconferencing network), but public resistance would be massive. Much economic dislocation would result since, for example, over 25% of retail sales are travel-related. The energy savings would be modest since only 25% of the nation's energy is consumed by transportation. However, all pollution would be reduced substantially since transportation accounts for 75% of the carbon monoxide, 60% of the hydrocarbon, and 55% of the nitrogen oxide pollution in the nation. Problems related to the implementation of large-scale substitution are discussed.

Application of household production theory to selected natural-resource problems in less-developed countries

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

Mercer, D.E.

The objectives are threefold: (1) to perform an analytical survey of household production theory as it relates to natural-resource problems in less-developed countries, (2) to develop a household production model of fuelwood decision making, (3) to derive a theoretical framework for travel-cost demand studies of international nature tourism. The model of household fuelwood decision making provides a rich array of implications and predictions for empirical analysis. For example, it is shown that fuelwood and modern fuels may be either substitutes or complements depending on the interaction of the gross-substitution and income-expansion effects. Therefore, empirical analysis should precede adoption of anymore » inter-fuel substitution policies such as subsidizing kerosene. The fuelwood model also provides a framework for analyzing the conditions and factors determining entry and exit by households into the wood-burning subpopulation, a key for designing optimal household energy policies in the Third World. The international nature tourism travel cost model predicts that the demand for nature tourism is an aggregate of the demand for the individual activities undertaken during the trip.« less

Synthesis and Characterization of Novel Transition Metal Chalcogenide Phases for Energy Storage, Energy Conversion and Optoelectronics

NASA Astrophysics Data System (ADS)

Chen, Erica Maxine

Today's energy needs are primarily provided by fossil fuels, which are harvested from the earth. Consuming fossil fuels to provide energy for civilization releases products into the atmosphere that contribute to climate change. Ongoing efforts to combat the existential crisis which climate change presents many of the emerging and commercialized technologies for solar, thermoelectric and battery applications involve transition metal chalcogenides. Some of the materials used for these applications are expensive and rare, such as gallium, vanadium and indium, or have no merits towards environmental stewardship, such as cadmium and lead. Thus, the purpose of this work is to further the ongoing effort to discover and develop new materials which are able to meet or exceed benchmarks for their application. This work focuses on the development of various metal chalcogenide material systems featuring d-block transition metals selected for their contribution to alter structure and properties. Various thermal, electronic and optical properties can be changed through substitution or doping with additional elements to affect to the base composition or as part of a gradient composition series. After an extensive description of experimental methods which describe the associated materials synthesis, processing and characterization techniques in chapter 2, chapter 3 explores the Cu4-xLixS 2 phases for their contribution as further evidence in the formation of lithiated copper sulfide phases as part of the intercalation reaction before being converted to the binaries copper and lithium sulfide. Chapter 4 documents the development of Cu4TiSe4, a novel material with potential for thin-film photovoltaic technologies with its band gap in the range where the solar spectrum is the most bountiful (Eg,indirect = 1.16 eV, Eg,direct = 1.34 eV), an outstanding optical absorbance ( > 10-4 cm-1) outperforming commercially successful materials in the solar spectrum, and suitable for thin-film fabrication. Chapter 5 describes a brief study in utilizing elemental substitution in Cu4TiSe4 to alter the band gap by replacing sulfur into the selenium site. In this study, the amount of selenium which may be substituted without deviating from the parent Cu4TiSe4 structure is 16 % at and the direct band gap is alterable from 1.34 eV to 1.64 eV as determined from conducting tauc analysis on the diffuse reflectance spectra. The last experimental work in Chapter 6 covers the development of a chemical substitution series between the end compounds Cu3NbS 4 and Cu3NbSe4. Through powdered x-ray diffraction of the series, it was found that for substituting less than 25% of the sulfur with selenium, the powdered patterns more closely resembled Cu3NbS 4 and with shift which may see further development and application in optoelectronic devices such as LEDs. Finally, Chapter 7 provides further guidance in the research which this thesis may serve as a springboard for the development of ultra-high efficiency, low-cost, environmentally friendly and thin photovoltaics as well as mention other characterization methods which are necessary to diagnose and elucidate complications.

Selenium-substituted polymers for improved photovoltaic performance.

PubMed

Yu, Jiangsheng; Ding, Guanqun; Hai, Jiefeng; Zhu, Enwei; Yin, Xinxing; Xu, Zhongsheng; Zhou, Baojing; Zhang, Fujun; Ma, Wanli; Tang, Weihua

2016-03-21

Four isostructural donor-acceptor alternating polymers of benzodithiophene (BDT)/naphthodifuran (NDF) and benzoselenadiazole (BSe)/benzothiadiazole (BT) have been developed and evaluated for organic photovoltaics. The substitution of one-atom (Se for S) in the accepting units exerts remarkable impact on the optoelectronic properties of polymers. Extended absorption, narrowed bandgap and higher HOMO energy levels were observed for Se-containing polymers in comparison to their S-containing counterparts. Theoretical calculations confirmed the measurable effect on energy levels as found in experimental studies. Bulk-heterojuction solar cells based on the BDT-BSe copolymer and [6,6]-phenyl-C71-butyric acid methyl ester (1 : 2, w/w) blend films deliver the best PCE of 5.40%. BSe-based polymers showed enhanced photovoltaic performances than BT-based polymers. The device performance is found to be strongly dependent on the processing conditions and morphology of the active layers.

Enhanced energy storage density in lead free (Na0.5Bi0.48Eu0.02)Ti1-xNbxO3(x=0.00, 0.01 & 0.02) ceramics

NASA Astrophysics Data System (ADS)

Yanamandra, Radha; Kandula, Kumara Raja; Bandi, Posidevi; Reddy, H. Satish Kumar; Asthana, Saket; Patri, Tirupathi

2018-05-01

Eco friendly (Na0.5Bi0.48Eu0.02) Ti1-xNbxO3 ceramics were synthesized with help of conventional solid state reaction by using high energy ball milling. The room temperature XRD of Nb5+ substituted NBET ceramics were stabilized in single phase pervoskite structure without any secondary phase. Polarization study reflects long range ferroelectric order for pure NBET ceramics and coercive field enhance with the substitution of Nb5+ ion at Ti site. Further, the substitution of Nb5+ ≥ 0.02 composition induced relaxor future. The energy density calculation shows the maximum energy storage density of 1.02 J/cm3 for x=0.02 ceramics. These results confirms a small fraction of Nb5+ doped NBET ceramics should be good candidates for energy storage applications.

Investigation of ionic transport in sodium scandium phosphate (NSP) and related compounds

NASA Astrophysics Data System (ADS)

Bhat, Kaustubh; Blügel, Stefan; Lustfeld, Hans

Sodium ionic conductors offer significant advantages for application in large scale energy storage systems. In this study, we investigate the different pathways available for sodium ion conduction in NSP and calculate energy barriers for ionic transport using Density Functional Theory (DFT) and the Nudged Elastic Band Method. We identify the structural parameters that reduce the energy barrier, by calculating the influence of positive and negative external pressure on the energy barrier. Lattice strain can be introduced by cation or anion substitution within the NASICON structure. We substitute the scandium atom with other trivalent atoms such as aluminium and yttrium, and calculate the resulting energy barriers. Sodium thiophosphate (Na3PS4) has previously shown about two orders of magnitude higher ionic conductivity than sodium phosphate (Na3PO4). We investigate the effect of substituting oxygen with sulphur in NSP. We acknowledge discussions with our experimental colleagues F. Tietz and M. Guin toward this work

Life Cycle Cost of Solar Biomass Hybrid Dryer Systems for Cashew Drying of Nuts in India

NASA Astrophysics Data System (ADS)

Dhanushkodi, Saravanan; Wilson, Vincent H.; Sudhakar, Kumarasamy

2015-12-01

Cashew nut farming in India is mostly carried out in small and marginal holdings. Energy consumption in the small scale cashew nut processing industry is very high and is mainly due to the high energy consumption of the drying process. The drying operation provides a lot of scope for energy saving and substitutions of other renewable energy sources. Renewable energy-based drying systems with loading capacity of 40 kg were proposed for application in small scale cashew nut processing industries. The main objective of this work is to perform economic feasibility of substituting solar, biomass and hybrid dryer in place of conventional steam drying for cashew drying. Four economic indicators were used to assess the feasibility of three renewable based drying technologies. The payback time was 1.58 yr. for solar, 1.32 for biomass and 1.99 for the hybrid drying system, whereas as the cost-benefit estimates were 5.23 for solar, 4.15 for biomass and 3.32 for the hybrid system. It was found that it is of paramount importance to develop solar biomass hybrid dryer for small scale processing industries.

The Electronic Structure and Formation Energies of Ni-doped CuAlO2 by Density Functional Theory Calculation

NASA Astrophysics Data System (ADS)

Xu, Ying; Li, Fei; Sheng, Wei; Nie, Guo-Zheng; Yuan, Ding-Wang

2014-03-01

The electronic structure and formation energies of Ni-doped CuAlO2 are calculated by first-principles calculations. Our results show that Ni is good for p-type doping in CuAlO2. When Ni is doped into CuAlO2, it prefers to substitute Al-site. NiAl is a shallow acceptor, while NiCu is a deep acceptor and its formation energy is high. Further electronic structure calculations show that strong hybridization happens between Ni-3d and O-2p states for Ni substituting Al-site, while localized Ni-3d states are found for Ni substituting Cu-site.

Substitution of Ni for Fe in superconducting Fe 0.98 Te 0.5 Se 0.5 depresses the normal-state conductivity but not the magnetic spectral weight

DOE PAGES

Wang, Jinghui; Zhong, Ruidan; Li, Shichao; ...

2015-01-05

We have performed systematic resistivity and inelastic neutron scattering measurements on Fe₀.₉₈₋ zNi zTe₀.₅Se₀.₅ samples to study the impact of Ni substitution on the transport properties and the low-energy (≤ 12 meV) magnetic excitations. It is found that, with increasing Ni doping, both the conductivity and superconductivity are gradually suppressed; in contrast, the low-energy magnetic spectral weight changes little. Comparing with the impact of Co and Cu substitution, we find that the effects on conductivity and superconductivity for the same degree of substitution grow systematically as the atomic number of the substituent deviates from that of Fe. The impact ofmore » the substituents as scattering centers appears to be greater than any contribution to carrier concentration. The fact that low-energy magnetic spectral weight is not reduced by increased electron scattering indicates that the existence of antiferromagnetic correlations does not depend on electronic states close to the Fermi energy.« less

Power Conversion and Energy Storage System for a Fusion Reactor 3. Performance of Large Electric Power Equipment and Future View 3.1 Large Capacity Battery System -Sodium-Sulfur Battery-

NASA Astrophysics Data System (ADS)

Nakabayashi, Takashi

The Ford Motor Company proposed the principle of the sodium-sulfur battery based on a beta-alumina solid electrolyte in 1967. Accordingly, sodium-sulfur battery technology was initially developed primarily for electric vehicle applications. Later, the Tokyo Electric Power Company (TEPCO) selected the sodium-sulfur battery technology as the preferred system for a dispersed utility energy storage system to substitute for the pumped hydro energy storage system. NGK Insulators, Ltd. (NGK) and TEPCO have jointly carried out the development of the sodium-sulfur battery since 1984. In April 2002, TEPCO and NGK made the sodium-sulfur battery for use as an energy storage system commercially available.

Energy saving incineration of waste

NASA Astrophysics Data System (ADS)

Meierzukoecker, H.; Voegtli, R.

1982-11-01

The machanism and the dimension of the preoxidation of the pollutants in the heat exchanger were investigated. A temperature control system was developed and tested. It is found that the preoxidation in the heat exchanger depends on the peculiarity of the pollutants and is inhibited by inactive walls with increasing of the specific surface. Active materials like copper only promote the oxidation of all pollutants in the low temperature region. Savings of supplemental energy about 25% are possible using process controlled auxiliary firing and combustion enthalpy of pollutants as a substitute for the supplemental energy.

Transition-metal-substituted indium thiospinels as novel intermediate-band materials: prediction and understanding of their electronic properties.

PubMed

Palacios, P; Aguilera, I; Sánchez, K; Conesa, J C; Wahnón, P

2008-07-25

Results of density-functional calculations for indium thiospinel semiconductors substituted at octahedral sites with isolated transition metals (M=Ti,V) show an isolated partially filled narrow band containing three t2g-type states per M atom inside the usual semiconductor band gap. Thanks to this electronic structure feature, these materials will allow the absorption of photons with energy below the band gap, in addition to the normal light absorption of a semiconductor. To our knowledge, we demonstrate for the first time the formation of an isolated intermediate electronic band structure through M substitution at octahedral sites in a semiconductor, leading to an enhancement of the absorption coefficient in both infrared and visible ranges of the solar spectrum. This electronic structure feature could be applied for developing a new third-generation photovoltaic cell.

A first-principles comparative study of lithium, sodium, and magnesium storage in pure and gallium-doped germanium: Competition between interstitial and substitutional sites

NASA Astrophysics Data System (ADS)

Legrain, Fleur; Manzhos, Sergei

2017-01-01

Thermodynamics and kinetics of Li, Na, and Mg storage in Ge are studied ab initio. The most stable configurations can consist of tetrahedral, substitutional, or a combination of the two types of sites. In the dilute limit, Li and Na prefer interstitial, while Mg prefers substitutional sites. At higher concentrations of Li, Na, and Mg, there is a combination of interstitial and substitutional sites. This is an important finding, as most previous ab initio studies of alloying type electrode materials ignored substitutional sites. Insertion energies computed at dilute concentration (x = 1/64) show that Na and Mg insertion are not thermodynamically favored in Ge vs. the formation of bulk Na and Mg, as opposed to Li insertion which is favored. We investigate the effect of p-doping of Ge (with Ga) on the thermodynamics and find that it considerably lowers the defect formation energies associated with the insertion of Li/Na/Mg at tetrahedral sites. On the other hand, the energetics associated with Li/Na/Mg insertion at substitutional sites are not significantly affected. In addition, we compute the migration energy barriers for Li/Na/Mg diffusion between two tetrahedral sites (0.38/0.79/0.66 eV), between two substitutional sites (0.77/0.93/1.83 eV), and between two sites of different types (2.15/1.75/0.85 eV).

A first-principles comparative study of lithium, sodium, and magnesium storage in pure and gallium-doped germanium: Competition between interstitial and substitutional sites.

PubMed

Legrain, Fleur; Manzhos, Sergei

2017-01-21

Thermodynamics and kinetics of Li, Na, and Mg storage in Ge are studied ab initio. The most stable configurations can consist of tetrahedral, substitutional, or a combination of the two types of sites. In the dilute limit, Li and Na prefer interstitial, while Mg prefers substitutional sites. At higher concentrations of Li, Na, and Mg, there is a combination of interstitial and substitutional sites. This is an important finding, as most previous ab initio studies of alloying type electrode materials ignored substitutional sites. Insertion energies computed at dilute concentration (x = 1/64) show that Na and Mg insertion are not thermodynamically favored in Ge vs. the formation of bulk Na and Mg, as opposed to Li insertion which is favored. We investigate the effect of p-doping of Ge (with Ga) on the thermodynamics and find that it considerably lowers the defect formation energies associated with the insertion of Li/Na/Mg at tetrahedral sites. On the other hand, the energetics associated with Li/Na/Mg insertion at substitutional sites are not significantly affected. In addition, we compute the migration energy barriers for Li/Na/Mg diffusion between two tetrahedral sites (0.38/0.79/0.66 eV), between two substitutional sites (0.77/0.93/1.83 eV), and between two sites of different types (2.15/1.75/0.85 eV).

Renewable energy sources in Bulgaria: Current state and trends

NASA Astrophysics Data System (ADS)

Kolev, K.

The over-dependency of Bulgaria on imported fuel stressed the importance of developing a new energy strategy based on energy saving which includes also using renewable energy sources (RES). The target is the substitution of at least 2 percent of the real primary energy consumption with RES by 2010. The author gives a generalized analysis of the available RES in Bulgaria -solar, wind, geothermal, biomass and mini-hydraulic. The potentialities of each source for its usage as a suitable energy supply are pointed out, as well as the current status of research and implementation work, problems connected with legislation, financing and production of particular facilities. The governmental policy concerning RES is considered briefly. A description is given to the project 'Technical and Economical Assessment of Possibilities for Expansion of the RES-part in the Energy Balance of the Country' developed and started in 1994 in the framework of the PHARE program.

Experimental Determination of Activation Energy of Nucleophilic Aromatic Substitution on Porphyrins

ERIC Educational Resources Information Center

Rizvi, Waqar; Khwaja, Emaad; Siddiqui, Saim; Bhupathiraju, N. V. S. Dinesh K.; Drain, Charles Michael

2018-01-01

A physical organic chemistry experiment is described for second-year college students. Students performed nucleophilic aromatic substitution (NAS) reactions on 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrin (TPPF[subscript 20]) using three different nucleophiles. Substitution occurs preferentially at the 4-position ("para")…

On the energy content of a money unit

NASA Astrophysics Data System (ADS)

Beaudreau, Bernard C.; Pokrovskii, Vladimir N.

2010-07-01

In this paper, the concept of “productive energy” as a substitute for conventional labour is examined historically, theoretically and empirically. Over the course of the last centuries, productive energy has been substituted for human, muscle- and brain-based work, providing the wherewithal for the phenomenal growth in material wealth in Western societies. In this era of rising energy costs and increasing energy scarcity, future growth appears to be compromised. To better understand the consequences for society, estimates of the energy content of a dollar’s worth of output are provided for the US and Russia.

Remarkable effect of halogenation of aromatic compounds on efficiency of nanowire formation through polymerization/crosslinking by high-energy single particle irradiation

NASA Astrophysics Data System (ADS)

Horio, Akifumi; Sakurai, Tsuneaki; Kayama, Kazuto; Lakshmi, G. B. V. S.; Kumar Avasthi, Devesh; Sugimoto, Masaki; Yamaki, Tetsuya; Chiba, Atsuya; Saito, Yuichi; Seki, Shu

2018-01-01

Irradiation of high-energy ion particles on organic films induced solid-state polymerization and crosslinking reactions of the materials along the ion trajectories, resulting in the formation of insoluble uniform nanowires with a precise diameter. The nanowires were isolated by the development process i.e. the irradiated film was immersed in organic solvents, and their morphology was visualized by atomic force microscopy. The target organic materials are 4-vinyltriphenylamine, poly(4-vinyltriphenylamine), and polystyrene derivatives with/without the partial substitutions by halogen atoms. It was found that 4-vinyltriphenylamines, in spite of their small molecular sizes, afforded nanowires more clearly than poly(4-vinyltriphenylamine)s. Moreover, the efficiency of demonstrated polymerization/crosslinking reactions obviously depends on the substituted halogen atom species. The averaged diameters of nanowires from bromo- or iodo- substituted 4-vinyltriphenylamine (9.3 and 9.4 nm, respectively) were larger than that obtained from simple 4-vinyltriphenylamine (6.8 nm). The remarkable effect of halogenation of aromatic compounds on the efficiency of the radiation-induced reactions was also observed for polystyrene derivatives. This contrast was considered to originate from the sum of the efficiency of elementary reactions including dissociative electron attachment.

Electronic structure of Pt-substituted clathrate silicides Ba{sub 8}Pt{sub x}Si{sub 46–x}(x = 4–6)

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

Borshch, N. A., E-mail: n.a.borshch@ya.ru

The results of calculation of the electronic structure of Si-based Pt-substituted clathrates are reported. Calculation is carried out by the linearized-augmented-plane-wave method. The effect of the number of substitutions and their crystallographic position in the unit cell on the electron-energy spectrum and the electronic properties of Pt-substituted clathrates is analyzed.

Induced innovation, energy prices, and the environment

NASA Astrophysics Data System (ADS)

Popp, David Clifford

The process of developing new technologies is a central question for economic theory as well as for public policy in many areas. For example, the development of cleaner, more efficient energy technologies will play an important role in reducing the threat of global warming. To study how technology evolves over time, this dissertation uses patent data on energy innovations from 1970 to 1991 to examine the impact of energy prices on energy-efficient innovations. Before this can be done, however, information on supply-side factors which influence innovation is also needed. In the case of innovation, supply-side factors are the usefulness of the existing base of scientific knowledge. Patent citations are used for this purpose. Subsequent citations to patents granted each year since 1970 are used to show that the returns to research and development (R&D) fall over time for most of the technologies studied. These estimates are then combined with data on demand-side factors, such as energy prices, to estimate a model of induced innovation in energy technologies. Both energy prices and the supply of knowledge are found to have strongly significant positive effects on innovation. Next, the Yale Technology Concordance (YTC), which maps patents to the industries in which they are used, is employed to construct a stock of energy-related knowledge for 14 energy intensive industries. The effect of changes in this stock on energy consumption in these industries is estimated. On average, the present value of energy savings resulting from a new patent is eight million dollars, with the maximum savings coming about five years after the initial patent application. Finally, the results of each regression are combined to simulate the impact of a ten percent energy tax. Initially, simple factor substitution due to the price change has the largest effect. However, because of the cumulative nature of R&D, induced innovation has a much larger effect than factor substitution in the long run. The evidence in this dissertation suggests that prices play an important role in influencing technological change, and that policy-makers can use this to their advantage in designing appropriate environmental policies.

Structural analysis of aluminium substituted nickel ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Singh, H. S.; Sangwa, Neha

2018-05-01

Aluminium substituted nickel ferrite nanoparticles were synthesized by High Energy Ball milling (HEBM) of the mixture of α-NiO, α-Al2O3 and α-Fe2O3 followed by annealing at 1000˚C. X-ray diffraction (XRD) and Energy dispersive spectroscopy analysis (EDS) characterization was done for Aluminium substituted nickel ferrite. The structural analysis reveals the formation of the single phase compound. The average grain size was estimated by X-ray diffraction technique ranges from 30 to 10 nm with the increasing concentration of Aluminium. EDS spectra conforms the homogeneous mixing and purity of ferrite.

Energy budgeting and carbon footprint of transgenic cotton-wheat production system through peanut intercropping and FYM addition.

PubMed

Singh, Raman Jeet; Ahlawat, I P S

2015-05-01

Two of the most pressing sustainability issues are the depletion of fossil energy resources and the emission of atmospheric green house gases like carbon dioxide to the atmosphere. The aim of this study was to assess energy budgeting and carbon footprint in transgenic cotton-wheat cropping system through peanut intercropping with using 25-50% substitution of recommended dose of nitrogen (RDN) of cotton through farmyard manure (FYM) along with 100% RDN through urea and control (0 N). To quantify the residual effects of previous crops and their fertility levels, a succeeding crop of wheat was grown with varying rates of nitrogen, viz. 0, 50, 100, and 150 kg ha(-1). Cotton + peanut-wheat cropping system recorded 21% higher system productivity which ultimately helped to maintain higher net energy return (22%), energy use efficiency (12%), human energy profitability (3%), energy productivity (7%), carbon outputs (20%), carbon efficiency (17%), and 11% lower carbon footprint over sole cotton-wheat cropping system. Peanut addition in cotton-wheat system increased the share of renewable energy inputs from 18 to 21%. With substitution of 25% RDN of cotton through FYM, share of renewable energy resources increased in the range of 21% which resulted into higher system productivity (4%), net energy return (5%), energy ratio (6%), human energy profitability (74%), energy productivity (6%), energy profitability (5%), and 5% lower carbon footprint over no substitution. The highest carbon footprint (0.201) was recorded under control followed by 50 % substitution of RDN through FYM (0.189). With each successive increase in N dose up to 150 kg N ha(-1) to wheat, energy productivity significantly reduced and share of renewable energy inputs decreased from 25 to 13%. Application of 100 kg N ha(-1) to wheat maintained the highest grain yield (3.71 t ha(-1)), net energy return (105,516 MJ ha(-1)), and human energy profitability (223.4) over other N doses applied to wheat. Application of 50 kg N ha(-1) to wheat maintained the least carbon footprint (0.091) followed by 100 kg N ha(-1) (0.100). Our study indicates that system productivity as well as energy and carbon use efficiencies of transgenic cotton-wheat production system can be enhanced by inclusion of peanut as an intercrop in cotton and substitution of 25% RDN of cotton through FYM, as well as application of 100 kg N ha(-1) to succeeding wheat crop.

76 FR 55609 - Energy Conservation Program for Consumer Products: Request for Exclusion of 120 Volt, 100 Watt...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-08

... of R20 Short Lamps and Unavailability of Substitutes D. Request for Information I. Background The... or has special characteristics not available in substitute lamp types. Specifically, as the lamp has... manufacturers (including designated beam spread and lumen output), there are no substitute products on the...

The role of energy in economic growth.

PubMed

Stern, David I

2011-02-01

This paper reviews the mainstream, resource economics, and ecological economics models of growth. A possible synthesis of energy-based and mainstream models is presented. This shows that when energy is scarce it imposes a strong constraint on the growth of the economy; however, when energy is abundant, its effect on economic growth is much reduced. The industrial revolution released the constraints on economic growth by the development of new methods of using coal and the discovery of new fossil fuel resources. Time-series analysis shows that energy and GDP cointegrate, and energy use Granger causes GDP when capital and other production inputs are included in the vector autoregression model. However, various mechanisms can weaken the links between energy and growth. Energy used per unit of economic output has declined in developed and some developing countries, owing to both technological change and a shift from poorer quality fuels, such as coal, to the use of higher quality fuels, especially electricity. Substitution of other inputs for energy and sectoral shifts in economic activity play smaller roles. © 2011 New York Academy of Sciences.

A first-principles study of carbon-related energy levels in GaN. I. Complexes formed by substitutional/interstitial carbons and gallium/nitrogen vacancies

NASA Astrophysics Data System (ADS)

Matsubara, Masahiko; Bellotti, Enrico

2017-05-01

Various forms of carbon based complexes in GaN are studied with first-principles calculations employing Heyd-Scuseria-Ernzerhof hybrid functionals within the framework of the density functional theory. We consider carbon complexes made of the combinations of single impurities, i.e., CN-CGa, CI-CN , and CI-CGa , where CN, CGa , and CI denote C substituting nitrogen, C substituting gallium, and interstitial C, respectively, and of neighboring gallium/nitrogen vacancies ( VGa / VN ), i.e., CN-VGa and CGa-VN . Formation energies are computed for all these configurations with different charge states after full geometry optimizations. From our calculated formation energies, thermodynamic transition levels are evaluated, which are related to the thermal activation energies observed in experimental techniques such as deep level transient spectroscopy. Furthermore, the lattice relaxation energies (Franck-Condon shift) are computed to obtain optical activation energies, which are observed in experimental techniques such as deep level optical spectroscopy. We compare our calculated values of activation energies with the energies of experimentally observed C-related trap levels and identify the physical origins of these traps, which were unknown before.

Nanoparticles of nickel oxide: growth and organization on zinc-substituted anionic clay matrix by one-pot route at room temperature

NASA Astrophysics Data System (ADS)

Carja, Gabriela; Nakajima, Akira; Dranca, Cristian; Okada, Kiyoshi

2010-10-01

A room temperature nanocarving strategy is developed for the fabrication of nanoparticles of nickel oxide on zinc-substituted anionic clay matrix (Ni/ZnLDH). It is based on the growth and organization of nanoparticles of nickel oxide which occur during the structural reconstruction of the layered structure of the anionic clay in NiSO4 aqueous solution. No organic compounds are used during the fabrication. The described material was characterized by X-ray diffraction (XRD), IR spectroscopy (FTIR), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Results show that the nickel-clay nanoarchitecture consists of small nanoparticles of nickel oxide (average size 7 nm) deposited on the larger nanoparticles (average size 90 nm) of zinc-substituted clay. The optical properties of the new nickel-zinc formulation are studied by UV-Vis.

Electroactive Reactive Oligomers and Polymers as Device Components

DTIC Science & Technology

2009-02-03

promise to impact the development of reflective and transmissive color-changing systems spanning ’smart’ polyclu’omic glassing technologies and e-papers...mediated cross-coupling reactions. While the first substitution is expected to have the largest impact on the energy gap of the donor-acceptor system, a...transmissive device applications, it is expected that processable black to transmissive analogues will impact the development of EC windows, e- papers and

Risk management with substitution options: Valuing flexibility in small-scale energy systems

NASA Astrophysics Data System (ADS)

Knapp, Karl Eric

Several features of small-scale energy systems make them more easily adapted to a changing operating environment than large centralized designs. This flexibility is often manifested as the ability to substitute inputs. This research explores the value of this substitution flexibility and the marginal value of becoming a "little more flexible" in the context of real project investment in developing countries. The elasticity of substitution is proposed as a stylized measure of flexibility and a choice variable. A flexible alternative (elasticity > 0) can be thought of as holding a fixed-proportions "nflexible" asset plus a sequence of exchange options---the option to move to another feasible "recipe" each period. Substitutability derives value from following a contour of anticipated variations and from responding to new information. Substitutability value, a "cost savings option", increases with elasticity and price risk. However, the required premium to incrementally increase flexibility can in some cases decrease with an increase in risk. Variance is not always a measure of risk. Tools from stochastic dominance are newly applied to real options with convex payoffs to correct some misperceptions and clarify many common modeling situations that meet the criteria for increased variance to imply increased risk. The behavior of the cost savings option is explored subject to a stochastic input price process. At the point where costs are identical for all alternatives, the stochastic process for cost savings becomes deterministic, with savings directly proportional to elasticity of substitution and price variance. The option is also formulated as a derivative security via dynamic programming. The partial differential equation is solved for the special case of Cobb-Douglas (elasticity = 1) (also shown are linear (infinite elasticity), Leontief (elasticity = 0)). Risk aversion is insufficient to prefer a more flexible alternative with the same expected value. Intertemporal links convert the sequence of independent options to a single compound option and require an expansion of the flexibility concept. Additional options increase the value of the project but generally decrease flexibility value. The framework is applied to case study in India: an urban industry electricity strategy decision with reliability risk.

Analysis of Protein Thermostability Enhancing Factors in Industrially Important Thermus Bacteria Species

PubMed Central

Kumwenda, Benjamin; Litthauer, Derek; Bishop, Özlem Tastan; Reva, Oleg

2013-01-01

Elucidation of evolutionary factors that enhance protein thermostability is a critical problem and was the focus of this work on Thermus species. Pairs of orthologous sequences of T. scotoductus SA-01 and T. thermophilus HB27, with the largest negative minimum folding energy (MFE) as predicted by the UNAFold algorithm, were statistically analyzed. Favored substitutions of amino acids residues and their properties were determined. Substitutions were analyzed in modeled protein structures to determine their locations and contribution to energy differences using PyMOL and FoldX programs respectively. Dominant trends in amino acid substitutions consistent with differences in thermostability between orthologous sequences were observed. T. thermophilus thermophilic proteins showed an increase in non-polar, tiny, and charged amino acids. An abundance of alanine substituted by serine and threonine, as well as arginine substituted by glutamine and lysine was observed in T. thermophilus HB27. Structural comparison showed that stabilizing mutations occurred on surfaces and loops in protein structures. PMID:24023508

Dielectric and AC conductivity studies of Nd substituted 0.8BaTiO{sub 3}-0.2(Bi{sub 0.5(1-x)}Nd{sub 0.5x}K{sub 0.5})TiO{sub 3} lead free ceramics

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

Ramesh, M. N. V.; Ramesh, K. V., E-mail: kv-ramesh5@yahoo.co.in

2016-05-23

0.8BaTiO{sub 3} – 0.2(Bi{sub 0.5(1-x)}Nd{sub 0.5x}K{sub 0.5})TiO{sub 3} (0.01 ≤ x ≤ 0.06) lead free ceramic materials have been prepared by solid state reaction method and followed by high energy ball milling process. X-ray diffraction studies confirm the tetragonal structure of the materials at room temperature. Lattice parameters and density are decreasing with increase of Nd substitution. Microstructure studies were done by using Scanning electron microscope and it found that grain size is decreasing with increase of Nd substitution. Temperature and frequency dependent dielectric studies reveal relaxor behaviour of the materials. Dielectric constant, dielectric loss and Curie temperature are decreasingmore » with Nd substitution. Maximum Curie temperature of 195°C was observed at 1 MHz for x=0.01 Nd substituted sample. Degree of diffuseness was calculated from the modified Curie-Weiss law and it is increasing with Nd substitution. AC conductivity is increasing with increase of Nd substitution and observed maximum activation energy of 0.52 eV for x=0.02 Nd substituted sample.« less

Lack of energy compensation over 4 days when white button mushrooms are substituted for beef.

PubMed

Cheskin, Lawrence J; Davis, Lisa M; Lipsky, Leah M; Mitola, Andrea H; Lycan, Thomas; Mitchell, Vanessa; Mickle, Brooke; Adkins, Emily

2008-07-01

Increasing intake of low energy density (ED) foods in place of high ED foods has been proposed as a strategy for preventing or treating obesity. This study investigated how substituting mushrooms for beef in a test lunch affected energy intake, fat intake, palatability, appetite, satiation and satiety in normal weight, overweight and obese adults. Each subject consumed a total of eight test lunches in our lab over two consecutive weeks. The order of presentation of four consecutive meat lunches and four consecutive mushroom lunches was randomized. Energy content of meat and mushroom lunches varied (783 kcal versus 339 kcal), while volume was held constant. Energy intakes were significantly higher during meat lunches than mushroom lunches (730+/-7.9 kcal versus 310+/-5.8 kcal). Subjects exhibited only partial compensation (11.4+/-12.0%) for this difference over 4 days. Total daily energy intake and fat intake were significantly greater in the meat condition than in the mushroom condition, while ratings of palatability, appetite, satiation and satiety did not differ significantly. These results suggest that substituting low ED foods for high ED foods in otherwise similar recipes can be an effective method for reducing daily energy and fat intake.

Cationic Gold Clusters Ligated with Differently Substituted Phosphines: Effect of Substitution on Ligand Reactivity and Binding

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

Johnson, Grant E.; Olivares, Astrid M.; Hill, David E.

2015-01-01

We present a systematic study of the effect of the number of methyl (Me) and cyclohexyl (Cy) functional groups in monodentate phosphine ligands on the solution-phase synthesis of ligated sub-nanometer gold clusters and their gas-phase fragmentation pathways. Small mixed ligand cationic gold clusters were synthesized using ligand exchange reactions between pre-formed triphenylphosphine ligated (PPh3) gold clusters and monodentate Me- and Cy-substituted ligands in solution and characterized using electrospray ionization mass spectrometry (ESI-MS) and collision-induced dissociation (CID) experiments. Under the same experimental conditions, larger gold-PPh3 clusters undergo efficient exchange of unsubstituted PPh3 ligands for singly Me- and Cy-substituted PPh2Me and PPh2Cymore » ligands. The efficiency of ligand exchange decreases with an increasing number of Me or Cy groups in the substituted phosphine ligands. CID experiments performed for a series of ligand-exchanged gold clusters indicate that loss of a neutral Me-substituted ligand is preferred over loss of a neutral PPh¬3 ligand while the opposite trend is observed for Cy-substituted ligands. The branching ratio of the competing ligand loss channels is strongly correlated with the electron donating ability of the phosphorous lone pair as determined by the relative proton affinity of the ligand. The results indicate that the relative ligand binding energies increase in the order PMe3 < PPhMe2 < PPh2Me < PPh3< PPh2Cy < PPhCy2< PCy3. Furthermore, the difference in relative ligand binding energies increases with the number of substituted PPh3-mMem or PPh3-mCym ligands (L) exchanged onto each cluster. This study provides the first experimental determination of the relative binding energies of ligated gold clusters containing differently substituted monophosphine ligands, which are important to controlling their synthesis and reactivity in solution. The results also indicate that ligand substitution is an important parameter that must be considered in theoretical modeling of these complex systems« less

Melt Miscibility in Block Copolymers Containing Polyethylene and Substituted Polynorbornenes

NASA Astrophysics Data System (ADS)

Mulhearn, William; Register, Richard

Very few polymer species exist with a sufficiently weak repulsive interaction against polyethylene (PE), characterized by a low Flory parameter χ or interaction energy density X, to be useful for preparing PE-containing block copolymers with disordered melts at high molecular weights. Most suitably miscible polymers are chemically similar to PE, such as copolymers of ethylene with a minority content of an α-olefin, and so are only marginally useful for property modification due to similar physical properties like the glass transition temperature (Tg) . However, the family of polymers consisting of substituted norbornenes prepared via ring-opening metathesis polymerization (ROMP) and subsequent hydrogenation is unique in that many of its members exhibit very low X against PE (comparable with the interaction energy between poly(ethylene-alt-propylene) and PE), and some of these also exhibit high Tg. The miscibility between PE and a substituted, hydrogenated ROMP polynobornene, or between two dissimilar hydrogenated polynorbornenes, is a strong function of the substituent appended to the norbornene monomer. The mixing thermodynamics of this polymer series are irregular, in that the interaction energies do not follow X = (δ1 - δ2)2 where δ is the solubility parameter. However, other systematic trends do apply and we develop a set of mixing rules to quantitatively describe the experimental miscibility behavior. We also investigate statistical copolymerization of two norbornene monomers as a means to continuously tune miscibility with a homopolymer of a third monomer.

A minimal peptide scaffold for beta-turn display: optimizing a strand position in disulfide-cyclized beta-hairpins.

PubMed

Cochran, A G; Tong, R T; Starovasnik, M A; Park, E J; McDowell, R S; Theaker, J E; Skelton, N J

2001-01-31

Phage display of peptide libraries has become a powerful tool for the evolution of novel ligands that bind virtually any protein target. However, the rules governing conformational preferences in natural peptides are poorly understood, and consequently, structure-activity relationships in these molecules can be difficult to define. In an effort to simplify this process, we have investigated the structural stability of 10-residue, disulfide-constrained beta-hairpins and assessed their suitability as scaffolds for beta-turn display. Using disulfide formation as a probe, relative free energies of folding were measured for 19 peptides that differ at a one strand position. A tryptophan substitution promotes folding to a remarkable degree. NMR analysis confirms that the measured energies correlate well with the degree of beta-hairpin structure in the disulfide-cyclized peptides. Reexamination of a subset of the strand substitutions in peptides with different turn sequences reveals linear free energy relationships, indicating that turns and strand-strand interactions make independent, additive contributions to hairpin stability. Significantly, the tryptophan strand substitution is highly stabilizing with all turns tested, and peptides that display model turns or the less stable C'-C' ' turn of CD4 on this tryptophan "stem" are highly structured beta-hairpins in water. Thus, we have developed a small, structured beta-turn scaffold, containing only natural L-amino acids, that may be used to display peptide libraries of limited conformational diversity on phage.

Life cycle assessment of energy from waste via anaerobic digestion: a UK case study.

PubMed

Evangelisti, Sara; Lettieri, Paola; Borello, Domenico; Clift, Roland

2014-01-01

Particularly in the UK, there is potential for use of large-scale anaerobic digestion (AD) plants to treat food waste, possibly along with other organic wastes, to produce biogas. This paper presents the results of a life cycle assessment to compare the environmental impacts of AD with energy and organic fertiliser production against two alternative approaches: incineration with energy production by CHP and landfill with electricity production. In particular the paper investigates the dependency of the results on some specific assumptions and key process parameters. The input Life Cycle Inventory data are specific to the Greater London area, UK. Anaerobic digestion emerges as the best treatment option in terms of total CO2 and total SO2 saved, when energy and organic fertiliser substitute non-renewable electricity, heat and inorganic fertiliser. For photochemical ozone and nutrient enrichment potentials, AD is the second option while incineration is shown to be the most environmentally friendly solution. The robustness of the model is investigated with a sensitivity analysis. The most critical assumption concerns the quantity and quality of the energy substituted by the biogas production. Two key issues affect the development and deployment of future anaerobic digestion plants: maximising the electricity produced by the CHP unit fuelled by biogas and to defining the future energy scenario in which the plant will be embedded. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dialkylthio Substitution: An Effective Method to Modulate the Molecular Energy Levels of 2D-BDT Photovoltaic Polymers.

PubMed

Yao, Huifeng; Zhang, Hao; Ye, Long; Zhao, Wenchao; Zhang, Shaoqing; Hou, Jianhui

2016-02-17

Dialkylthio-substituted thienyl-benzodithiophene (BDT-DST) was designed and synthesized as a building block to modulate the molecular levels of the conjugated polymers, and three copolymers named PDST-BDD, PDST-TT and PDST-DPP were prepared and applied in polymer solar cells (PSCs). Theoretical calculations and electrochemical cyclic voltammetry (CV) measurement suggested that the dialkylthio group could decrease the molecular energy levels of the resulting polymers distinctly. The open-circuit voltage (VOC) of PSC devices based on PDST-BDD, PDST-TT, and PDST-DPP are as high as 1.0, 0.98, and 0.88 V, respectively, which are ∼0.15 V higher than those of the corresponding alky-substituted analogues. Moreover, the influence of the dialkylthio group on the absorption spectra, crystalline properties, hole mobilities, and blend morphologies of the polymers was also investigated. The results indicate that the dialkythio substitution is an effective method to modulate the molecular energy levels and that the BDT-DST unit has potential for constructing high-efficiency photovoltaic polymers.

Heat-pump-centered integrated community energy systems: System development summary

NASA Astrophysics Data System (ADS)

Calm, J. M.

1980-02-01

An introduction to district heating systems employing heat pumps to enable use of low temperature energy sources is presented. These systems operate as thermal utilities to provide space heating and may also supply space cooling, service water heating, and other thermal services. Otherwise wasted heat from industrial and commercial processes, natural sources including solar and geothermal heat, and heat stored on an annual cycle from summer cooling may be effectively utilized by the systems described. More than one quarter of the energy consumed in the United States is used to heat and cool buildings and to heat service water. Natural gas and oil provide approximately 83% of this energy. The systems described show potential to reduce net energy consumption for these services by 20 to 50% and to allow fuel substitution with less scarce resources not practical in smaller, individual building systems. Seven studies performed for the system development phase are summarized.

A comparative study between para-aminophenyl and ortho-aminophenyl benzothiazoles using NMR and DFT calculations.

PubMed

Pierens, G K; Venkatachalam, T K; Reutens, D

2014-08-01

Ortho-substituted and para-substituted aminophenyl benzothiazoles were synthesised and characterised using NMR spectroscopy. A comparison of the proton chemical shift values reveals significant differences in the observed chemical shift values for the NH protons indicating the presence of a hydrogen bond in all ortho-substituted compounds as compared to the para compounds. The presence of intramolecular hydrogen bond in the ortho amino substituted aminophenyl benzothiazole forces the molecule to be planar which may be an additional advantage in developing these compounds as Alzheimer's imaging agent because the binding to amyloid fibrils prefers planar compounds. The splitting pattern of the methylene proton next to the amino group also showed significant coupling to the amino proton consistent with the notion of the existence of slow exchange and hydrogen bond in the ortho-substituted compounds. This is further verified by density functional theory calculations which yielded a near planar low energy conformer for all the o-aminophenyl benzothiazoles and displayed a hydrogen bond from the amine proton to the nitrogen of the thiazole ring. A detailed analysis of the (1)H, (13)C and (15)N NMR chemical shifts and density functional theory calculated structures of the compounds are described. Copyright © 2014 John Wiley & Sons, Ltd.

A molecular mechanics study of the effect of substitution in position 1 on the conformational space of the oxytocin/vasopressin ring

NASA Astrophysics Data System (ADS)

Tarnowska, Monika; Liwo, Adam; Shenderovich, Mark D.; Liepiņa, Inta; Golbraikh, Alexander A.; Grzonka, Zbigniew; Tempczyk, Anna

1993-12-01

The effect of the substitution in position 1 on the low-energy conformations of the oxytocin/vasopressin 20-membered ring was investigated by means of molecular mechanics. Three representative substitutions were considered: β'-mercapto-β,β-dimethyl)propionic acid (Dmp), (β'-mercapto-β,β-cyclopentamethylene)propionic acid (Cpp), both forming strong antagonists, and (α,α-dimethyl-β-mercapto)propionic acid (α-Dmp), forming analogs of strongly reduced biological activity, with the β-mercaptopropionic (Mpa) residue taken as reference. Both ECEPP/2 (rigid valence geometry) and AMBER (flexible valence geometry) force fields were employed in the calculations. Three basic types of backbone conformations were taken into account which are distinguished by the type of β-turn at residues 3 and 4: β1/βIII, βII, and βI'/βIII', all types containing one or two intra-annular hydrogen bonds. The allowed (ring-closed) disulfide-bridge conformations were searched by an algorithm formulated in terms of scanning the disulfide-bridge torsional angle Cβ-S-S-Cβ. The ECEPP/2 and AMBER energies of the obtained conformations were found to be in reasonable agreement. Two of the low-energy conformers of the [Mpa1]-compound agreed very well with the cyclic part of the two conformers found in the crystal structure of [Mpa1]-oxytocin. An analysis of the effect of β-substitution on relative energies showed that the conformations with the N-C'-CH2-CH2 (ψ'1) and C'-CH2-CH2-S (ϰ'1) angles of the first residue around (-100°, 60°) and (100°, -60°) are not affected; this in most cases implies a left-handed disulfide bridge. In the case of α-substitution the allowed values of ψ'1 are close to ± 60°. This requirement, being in contradiction to the one concerning β-substitution, could explain the very low biological activity of the α-substituted analogs. The conformational preferences of substituted compounds can largely be explained by the analysis of local interactions within the first residue. Based on the selection of the conformations which are low in energy for both the reference and β-substituted compounds, two distinct types of possible binding conformations were proposed, the first one being similar to the crystal conformer with a left-handed disulfide bridge, the second one having a right-handed bridge, but a geometry different from that of the crystal conformer with the right-handed bridge. The first type of disulfide-bridge arrangement is equally favorable for both βI/βIII and βII types of backbone structure, while the second one is allowed only for the βII type of backbone. No conformation of the βI'/βIII' type has a low enough energy to be considered as a possible binding conformation for all of the active compounds studied in this work.

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

Kelly, Jarod C.; Sullivan, John L.; Burnham, Andrew

This study examines the vehicle-cycle impacts associated with substituting lightweight materials for those currently found in light-duty passenger vehicles. We determine part-based energy use and greenhouse gas (GHG) emission ratios by collecting material substitution data from both the literature and automotive experts and evaluating that alongside known mass-based energy use and GHG emission ratios associated with material pair substitutions. Several vehicle parts, along with full vehicle systems, are examined for lightweighting via material substitution to observe the associated impact on GHG emissions. Results are contextualized by additionally examining fuel-cycle GHG reductions associated with mass reductions relative to the baseline vehiclemore » during the use phase and also determining material pair breakeven driving distances for GHG emissions. The findings show that, while material substitution is useful in reducing vehicle weight, it often increases vehicle-cycle GHGs depending upon the material substitution pair. However, for a vehicle’s total life cycle, fuel economy benefits are greater than the increased burdens associated with the vehicle manufacturing cycle, resulting in a net total life-cycle GHG benefit. The vehicle cycle will become increasingly important in total vehicle life-cycle GHGs, since fuel-cycle GHGs will be gradually reduced as automakers ramp up vehicle efficiency to meet fuel economy standards.« less

Implications of shale gas development for climate change.

PubMed

Newell, Richard G; Raimi, Daniel

2014-01-01

Advances in technologies for extracting oil and gas from shale formations have dramatically increased U.S. production of natural gas. As production expands domestically and abroad, natural gas prices will be lower than without shale gas. Lower prices have two main effects: increasing overall energy consumption, and encouraging substitution away from sources such as coal, nuclear, renewables, and electricity. We examine the evidence and analyze modeling projections to understand how these two dynamics affect greenhouse gas emissions. Most evidence indicates that natural gas as a substitute for coal in electricity production, gasoline in transport, and electricity in buildings decreases greenhouse gases, although as an electricity substitute this depends on the electricity mix displaced. Modeling suggests that absent substantial policy changes, increased natural gas production slightly increases overall energy use, more substantially encourages fuel-switching, and that the combined effect slightly alters economy wide GHG emissions; whether the net effect is a slight decrease or increase depends on modeling assumptions including upstream methane emissions. Our main conclusions are that natural gas can help reduce GHG emissions, but in the absence of targeted climate policy measures, it will not substantially change the course of global GHG concentrations. Abundant natural gas can, however, help reduce the costs of achieving GHG reduction goals.

Novel catalysts and photoelectrochemical system for solar fuel production

NASA Astrophysics Data System (ADS)

Zhang, Yan

Solar fuel production from abundant raw chemicals such as CO2 and water is highly desired as a clean renewable energy solution for the future. Developing photoelectrochemical cells is viewed as a promising approach to realize this energy conversion and storage process. Efficient and robust oxygen evolution catalyst made from non-precious materials remains a major challenge for such a system. This thesis basically consists of three parts of work, including studies on enhancing the photocatalytic oxygen evolution activity of cobalt-based spinel nanoparticles by manganese3+ substitution, in situ formation of cobalt oxide nanocubanes as highly active catalyst for photocatalytic oxygen evolution reaction, and development of a photoanode-driven photoelectrochemical cell for CO2 reduction with water. The first part of this thesis work devotes efforts in the development and study on cobalt and other transition metal oxide based oxygen evolution catalyst. Photocatalytic oxygen evolution is a critical step for solar fuel production from abundant sources. It poses a significant challenge because it requires an efficient catalyst to bridge the one-electron photon capture process with the four-electron oxygen reaction. Among all the metal oxides, Co3O4 spinel exhibits a high activity as an oxygen evolution catalyst. The results of this work demonstrate that the photocatalytic oxygen evolution activity of Co3O4 spinel can be further enhanced by substituting Co with Mn in the spinel structure. Using a facile hydrothermal approach, Co3O4 spinel nanoparticles as well as Mn-substituted and Ni-substituted Co3O4 spinel nanoparticles with a typical particle size of 5-7 nm were successfully synthesized. The morphology and crystal structures of the as-synthesized nanoparticle catalysts have been carefully examined using various structural characterization techniques, including powder x-ray diffraction (PXRD), transmission electron microscope (TEM), gas adsorption, and x-ray absorption spectroscopy (XAS). The photocatalytic activities of as-made nanoparticles were investigated using a well-studied visible light driven [Ru(bpy)3]2+-persulfate system. In both Clark electrode and reactor/gas chromatography (GC) systems, Mn-substituted Co3O 4 nanoparticles exhibited the highest turnover frequency (TOF) among all the three kinds of catalysts. The data presented in this paper suggest that the photocatalytic oxygen evolution activity of Co3O 4 spinel catalyst can be further enhanced by Mn3+ substitution at the octahedral sites. The second part of this piece of work was carried out to further investigate cobalt oxide based photocatalytic oxygen evolution catalyst. A new strategy was developed to synthesize nonsupported cobalt oxide nanocubanes through an in situ phase transformation mechanism using a layered Co(OH)(OCH3) precursor. Under sonication, the precursor was exfoliated and transformed into cobalt oxide nanocubanes in the presence of NaHCO 3-Na2SiF6 buffer solution. The resulting cobalt catalyst with an average particle size less than 2 nm exhibited a turnover frequency of 0.0023 per second per cobalt in photocatalytic oxygen evolution reaction. X-ray absorption results suggested that a unique nanocubane structure, where 13 cobalt atoms fully coordinated with oxygen atoms and hydroxide groups in an octahedral arrangement to form 8 Co4O4 cubanes, may be responsible for the exceptionally high oxygen evolution catalysis activity. This thesis work is completed with the development of a photoanode-driven photoelectrochemical cell for CO2 reduction. A NiOx decorated Si photoanode and nanoporous Ag cathode were employed. With an external bias of 2.0 V, a current density at cathode of 10 mA/cm2 and Faradaic efficiency of 70% for CO2 to CO was achieved. Compared to a normal electrochemical cell, the photoelectrochemical cell saves 0.4 V electrical energy by absorbing photo-energy. In addition, post-test photoanodes were carefully characterized by SEM, XAS, and XPS analysis.

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

Not Available

The coal industry, the utilities, and the state government are planning for development of high-energy coal gasification in Illinois to convert its abundant high-sulfur coal supply to a substitute natural gas. Following a summary of the findings, the following topics are discussed briefly: Illinois coal and the push for coal gasification; coal gasification: a look at the process; potential sites for an Illinois coal gasification industry; the impact of coal gasification's water requirements; solid wastes from coal gasification; land losses: the impact on agriculture; potential human health problems with coal gasification; the energy efficiency of coal gasification; potential economic impactsmore » of coal gasification; the corporations behind high-energy coal gasification; state involvement: legalizing the losses of the people; the national energy picture: the impact of western coal developments on Illinois; action: what you can do now. 27 references. (MCW)« less

Tuning the Ground State Symmetry of Acetylenyl Radicals

PubMed Central

2015-01-01

The lowest excited state of the acetylenyl radical, HCC, is a 2Π state, only 0.46 eV above the ground state, 2Σ+. The promotion of an electron from a π bond pair to a singly occupied σ hybrid orbital is all that is involved, and so we set out to tune those orbital energies, and with them the relative energetics of 2Π and 2Σ+ states. A strategy of varying ligand electronegativity, employed in a previous study on substituted carbynes, RC, was useful, but proved more difficult to apply for substituted acetylenyl radicals, RCC. However, π-donor/acceptor substitution is effective in modifying the state energies. We are able to design molecules with 2Π ground states (NaOCC, H2NCC (2A″), HCSi, FCSi, etc.) and vary the 2Σ+–2Π energy gap over a 4 eV range. We find an inconsistency between bond order and bond dissociation energy measures of the bond strength in the Si-containing molecules; we provide an explanation through an analysis of the relevant potential energy curves. PMID:27162981

Factor demand in Swedish manufacturing industry with special reference to the demand for energy. Instantaneous adjustment models; some results

NASA Astrophysics Data System (ADS)

Sjoeholm, K. R.

1981-02-01

The dual approach to the theory of production is used to estimate factor demand functions of the Swedish manufacturing industry. Two approximations of the cost function, the translog and the generalized Leontief models, are used. The price elasticities of the factor demand do not seem to depend on the choice of model. This is at least true as to the sign pattern and as to the inputs capital, labor, total energy and other materials. Total energy is separated into solid fuels, gasoline, fuel oil, electricity and a residual. Fuel oil and electricity are found to be substitutes by both models. Capital and energy are shown to be substitutes. This implies that Swedish industry will save more energy if the capital cost can be reduced. Both models are, in the best versions, able to detect an inappropriate variable. The assumption of perfect competition on the product market, is shown to be inadequate by both models. When this assumption is relaxed, the normal substitution pattern among the inputs is resumed.

Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

NASA Astrophysics Data System (ADS)

Yusof, Mohd Fahmi Mohd; Hamid, Puteri Nor Khatijah Abdul; Bauk, Sabar; Hashim, Rokiah; Tajuddin, Abdul Aziz

2015-04-01

Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest value of CT number to water substitute at 80 and 120 kVp CT energies with χ2 value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ2 value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.

Determination of CT number and density profile of binderless, pre-treated and tannin-based Rhizophora spp. particleboards using computed tomography imaging and electron density phantom

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

Yusof, Mohd Fahmi Mohd, E-mail: mfahmi@usm.my; Hamid, Puteri Nor Khatijah Abdul; Tajuddin, Abdul Aziz

2015-04-29

Plug density phantoms were constructed in accordance to CT density phantom model 062M CIRS using binderless, pre-treated and tannin-based Rhizophora Spp. particleboards. The Rhizophora Spp. plug phantoms were scanned along with the CT density phantom using Siemens Somatom Definition AS CT scanner at three CT energies of 80, 120 and 140 kVp. 15 slices of images with 1.0 mm thickness each were taken from the central axis of CT density phantom for CT number and CT density profile analysis. The values were compared to water substitute plug phantom from the CT density phantom. The tannin-based Rhizophora Spp. gave the nearest valuemore » of CT number to water substitute at 80 and 120 kVp CT energies with χ{sup 2} value of 0.011 and 0.014 respectively while the binderless Rhizphora Spp. gave the nearest CT number to water substitute at 140 kVp CT energy with χ{sup 2} value of 0.023. The tannin-based Rhizophora Spp. gave the nearest CT density profile to water substitute at all CT energies. This study indicated the suitability of Rhizophora Spp. particleboard as phantom material for the use in CT imaging studies.« less

Theory of p-type Zinc Oxide

NASA Astrophysics Data System (ADS)

Zhang, Shengbai

2002-03-01

Recent advances in bipolar doping of wide gap semiconductors challenge our understanding of impurity and defect properties in these materials, as theories based on equilibrium thermodynamics cannot keep up with these recent developments. For ZnO, the puzzling experimental results involve doping with nitrogen(M. Joseph, H. Tabata, and T. Kawai, Jpn. J. Appl. Phys. 38), L1205 (1999)., arsenic(Y. R. Ryu, S. Zhu, D. C. Look, J. M. Wrobel, H. M. Jeong, and H. W. White, J. Crys. Growth 216), 330 (2000)., and phosphorus(T. Aoki, Y. Hatanaka, and D. C. Look, Appl. Phys. Lett. 76), 3257 (2000).. In this talk, I will discuss some recent theoretical efforts trying to explain the experiments by first-principles total energy calculations. I will first discuss the acceptor level positions for group I and group V impurities. A general trend is observed(C. H. Park, S. B. Zhang, and S.-H. Wei, submitted to Phys. Rev. B.) that substitutional group V impurities on O range from relatively deep (e.g. N) to very deep (e.g. P and As) with high formation energies, whereas substitutional group I impurities on Zn are shallow acceptors. However, substitutional group I impurities are unstable against the formation of interstitials that are donors. A careful examination of N doping in Ref. [1] suggests that one can kinetically suppress the formation of N2 molecules by engineering dopant sources/footnoteY. Yan, S. B. Zhang, and S. T. Pantelides, Phys. Rev. Lett. 86, 5723 (2001).. This leads to significantly enhanced N solubility and hence p-type ZnO. For As [2], our preliminary studies show that the formation energy of AsO is so high that it is an exothermic process to form low-energy complexes that act effectively as relatively shallow acceptors.

Biofuels from food processing wastes.

PubMed

Zhang, Zhanying; O'Hara, Ian M; Mundree, Sagadevan; Gao, Baoyu; Ball, Andrew S; Zhu, Nanwen; Bai, Zhihui; Jin, Bo

2016-04-01

Food processing industry generates substantial high organic wastes along with high energy uses. The recovery of food processing wastes as renewable energy sources represents a sustainable option for the substitution of fossil energy, contributing to the transition of food sector towards a low-carbon economy. This article reviews the latest research progress on biofuel production using food processing wastes. While extensive work on laboratory and pilot-scale biosystems for energy production has been reported, this work presents a review of advances in metabolic pathways, key technical issues and bioengineering outcomes in biofuel production from food processing wastes. Research challenges and further prospects associated with the knowledge advances and technology development of biofuel production are discussed. Copyright © 2016. Published by Elsevier Ltd.

Life cycle environmental impacts of substituting food wastes for traditional anaerobic digestion feedstocks.

PubMed

Pérez-Camacho, María Natividad; Curry, Robin; Cromie, Thomas

2018-03-01

In this study, life cycle assessment has been used to evaluate life cycle environmental impacts of substituting traditional anaerobic digestion (AD) feedstocks with food wastes. The results have demonstrated the avoided GHG emissions from substituting traditional AD feedstocks with food waste (avoided GHG-eq emissions of 163.33 CO 2 -eq). Additionally, the analysis has included environmental benefits of avoided landfilling of food wastes and digestate use as a substitute for synthetic fertilisers. The analysis of the GHG mitigation benefits of resource management/circular economy policies, namely, the mandating of a ban on the landfilling of food wastes, has demonstrated the very substantial GHG emission reduction that can be achieved by these policy options - 2151.04 kg CO 2 eq per MWh relative to UK Grid. In addition to the reduction in GHG emission, the utilization of food waste for AD instead of landfilling can manage the leakage of nutrients to water resources and eliminate eutrophication impacts which occur, typically as the result of field application. The results emphasise the benefits of using life-cycle thinking to underpin policy development and the implications for this are discussed with a particular focus on the analysis of policy development across the climate, renewable energy, resource management and bioeconomy nexus and recommendations made for future research priorities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Global carbon benefits of material substitution in passenger cars until 2050 and the impact on the steel and aluminum industries.

PubMed

Modaresi, Roja; Pauliuk, Stefan; Løvik, Amund N; Müller, Daniel B

2014-09-16

Light-weighting of passenger cars using high-strength steel or aluminum is a common emissions mitigation strategy. We provide a first estimate of the global impact of light-weighting by material substitution on GHG emissions from passenger cars and the steel and aluminum industries until 2050. We develop a dynamic stock model of the global car fleet and combine it with a dynamic MFA of the associated steel, aluminum, and energy supply industries. We propose four scenarios for substitution of conventional steel with high-strength steel and aluminum at different rates over the period 2010-2050. We show that light-weighting of passenger cars can become a "gigaton solution": Between 2010 and 2050, persistent light-weighting of passenger cars can, under optimal conditions, lead to cumulative GHG emissions savings of 9-18 gigatons CO2-eq compared to development business-as-usual. Annual savings can be up to 1 gigaton per year. After 2030, enhanced material recycling can lead to further reductions: closed-loop metal recycling in the automotive sector may reduce cumulative emissions by another 4-6 gigatons CO2-eq. The effectiveness of emissions mitigation by material substitution significantly depends on how the recycling system evolves. At present, policies focusing on tailpipe emissions and life cycle assessments of individual cars do not consider this important effect.

Hydrogen isotopic substitution of solid methylamine through atomic surface reactions at low temperatures: A potential contribution to the D/H ratio of methylamine in molecular clouds

NASA Astrophysics Data System (ADS)

Oba, Yasuhiro; Chigai, Takeshi; Osamura, Yoshihiro; Watanabe, Naoki; Kouchi, Akira

2014-01-01

We experimentally studied hydrogen (H)-deuterium (D) substitution reactions of solid methylamine (CH3NH2) under astrophysically relevant conditions. We also calculated the potential energy surface for the H-D substitution reactions of methylamine isotopologues using quantum chemical methods. Despite the relatively large energy barrier of more than 18 kJ mol-1, CH3NH2 reacted with D atoms to yield deuterated methylamines at 10 K, suggesting that the H-D substitution reaction proceeds through quantum tunneling. Deuterated methylamines reacted with H atoms as well. On the basis of present results, we propose that methylamine has potential for D enrichment through atomic surface reactions on interstellar grains at very low temperatures in molecular clouds. D enrichment would occur in particular in the methyl group of methylamine.

The association of substituting carbohydrates with total fat and different types of fatty acids with mortality and weight change among diabetes patients.

PubMed

Campmans-Kuijpers, Marjo J; Sluijs, Ivonne; Nöthlings, Ute; Freisling, Heinz; Overvad, Kim; Boeing, Heiner; Masala, Giovanna; Panico, Salvatore; Tumino, Rosario; Sieri, Sabina; Johansson, Ingegerd; Winkvist, Anna; Katzke, Verena A; Kuehn, Tilman; Nilsson, Peter M; Halkjær, Jytte; Tjønneland, Anne; Spijkerman, Annemieke M; Arriola, Larraitz; Sacerdote, Carlotta; Barricarte, Aurelio; May, Anne M; Beulens, Joline W

2016-10-01

Substitution of carbohydrates with fat in a diet for type 2 diabetes patients is still debated. This study aimed to investigate the association between dietary carbohydrate intake and isocaloric substitution with (i) total fat, (ii) saturated fatty acids (SFA), (iii) mono-unsaturated fatty acids (MUFA) and (iv) poly-unsaturated fatty acids (PUFA) with all-cause and cardiovascular (CVD) mortality risk and 5-year weight change in patients with type 2 diabetes. The study included 6192 patients with type 2 diabetes from 15 cohorts of the European Prospective Investigation into Cancer and Nutrition (EPIC). Dietary intake was assessed at recruitment with country-specific food-frequency questionnaires. Cox and linear regression were used to estimate the associations with (CVD) mortality and weight change, adjusting for confounders and using different methods to adjust for energy intake. After a mean follow-up of 9.2 y ± SD 2.3 y, 791 (13%) participants had died, of which 268 (4%) due to CVD. Substituting 10 g or 5 energy% of carbohydrates by total fat was associated with a higher all-cause mortality risk (HR 1.07 [1.02-1.13]), or SFAs (HR 1.25 [1.11-1.40]) and a lower risk when replaced by MUFAs (HR 0.89 [0.77-1.02]). When carbohydrates were substituted with SFAs (HR 1.22 [1.00-1.49]) or PUFAs (HR 1.29 [1.02-1.63]) CVD mortality risk increased. The 5-year weight was lower when carbohydrates were substituted with total fat or MUFAs. These results were consistent over different energy adjustment methods. In diabetes patients, substitution of carbohydrates with SFAs was associated with a higher (CVD) mortality risk and substitution by total fat was associated with a higher all-cause mortality risk. Substitution of carbohydrates with MUFAs may be associated with lower mortality risk and weight reduction. Instead of promoting replacement of carbohydrates by total fat, dietary guideline should continue focusing on replacement by fat-subtypes; especially SFAs by MUFAs. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Substitution for petroleum products in Brasil: Urgent issues

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

de Araujo, J.L.; Ghirardi, A.

Brazililan energy policy during the last decade has focused on the replacement of imported petroleum with domestic energy sources, combined with efforts at conservation. The substitution results, however, have been more spectacular by far. The strategy of replacement is based on two elements. first, to increase domestic petroleum exploration and production. Second, to promote non-petroleum fuels as alternatives to the industrial and transportation sectors, for the substitution of fuel oil and gasoline, respectively. A combination of the substitution strategy, the country's petroleum refining structure, and the composition of the substitution strategy, the country's petroleum refining structure, and the composition ofmore » demand, has resulted in large surpluses of both gasoline and fuel oil, while diesel has become the most used among petroleum products. The surpluses are not easily exportable because there is ample availability of fuel oil in the world market, and because the low octane number of the gasoline produced in Brasil is not compatible with the engines of cars elsewhere in the region and in the world. Furthermore, although gasoline might be upgraded, the question remains that prospects for the world market are not encouraging, and an export-based strategy does not seem justified in view of the growing surpluses. The objective of this analysis is to review the mechanisms of themajor petroleum-substitution programs currently in existence, identifying their past impact on the energy market and the possible consequences of changes in the goals and operating conditions of these programs, in the light of the new prospects for increased domestic oil production and self-sufficiency. 23 refs., 2 figs., 1 tab.« less

Energy recovery from waste incineration: assessing the importance of district heating networks.

PubMed

Fruergaard, T; Christensen, T H; Astrup, T

2010-07-01

Municipal solid waste incineration contributes with 20% of the heat supplied to the more than 400 district heating networks in Denmark. In evaluation of the environmental consequences of this heat production, the typical approach has been to assume that other (fossil) fuels could be saved on a 1:1 basis (e.g. 1GJ of waste heat delivered substitutes for 1GJ of coal-based heat). This paper investigates consequences of waste-based heat substitution in two specific Danish district heating networks and the energy-associated interactions between the plants connected to these networks. Despite almost equal electricity and heat efficiencies at the waste incinerators connected to the two district heating networks, the energy and CO(2) accounts showed significantly different results: waste incineration in one network caused a CO(2) saving of 48 kg CO(2)/GJ energy input while in the other network a load of 43 kg CO(2)/GJ. This was caused mainly by differences in operation mode and fuel types of the other heat producing plants attached to the networks. The paper clearly indicates that simple evaluations of waste-to-energy efficiencies at the incinerator are insufficient for assessing the consequences of heat substitution in district heating network systems. The paper also shows that using national averages for heat substitution will not provide a correct answer: local conditions need to be addressed thoroughly otherwise we may fail to assess correctly the heat recovery from waste incineration. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Investigation of magnetism in aluminum-doped silicon carbide nanotubes

NASA Astrophysics Data System (ADS)

Behzad, Somayeh; Chegel, Raad

2013-11-01

The effect of aluminum doping on the structural, electronic and magnetic properties of (8,0) silicon carbide nanotube (SiCNT) is investigated using spin-polarized density functional theory. It is found from the calculation of the formation energies that aluminum substitution for silicon atom is preferred. Our results show that the magnetization depends on the substitutional site, aluminum substitution at silicon site does not introduce any spin-polarization, whereas the aluminum substitution for carbon atom yields a spin polarized, almost dispersionless π band within the original band gap.

Comparative Ab-Initio Study of Substituted Norbornadiene-Quadricyclane Compounds for Solar Thermal Storage.

PubMed

Kuisma, Mikael J; Lundin, Angelica M; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

2016-02-25

Molecular photoswitches that are capable of storing solar energy, so-called molecular solar thermal storage systems, are interesting candidates for future renewable energy applications. In this context, substituted norbornadiene-quadricyclane systems have received renewed interest due to recent advances in their synthesis. The optical, thermodynamic, and kinetic properties of these systems can vary dramatically depending on the chosen substituents. The molecular design of optimal compounds therefore requires a detailed understanding of the effect of individual substituents as well as their interplay. Here, we model absorption spectra, potential energy storage, and thermal barriers for back-conversion of several substituted systems using both single-reference (density functional theory using PBE, B3LYP, CAM-B3LYP, M06, M06-2x, and M06-L functionals as well as MP2 calculations) and multireference methods (complete active space techniques). Already the diaryl substituted compound displays a strong red-shift compared to the unsubstituted system, which is shown to result from the extension of the conjugated π-system upon substitution. Using specific donor/acceptor groups gives rise to a further albeit relatively smaller red-shift. The calculated storage energy is found to be rather insensitive to the specific substituents, although solvent effects are likely to be important and require further study. The barrier for thermal back-conversion exhibits strong multireference character and as a result is noticeably correlated with the red-shift. Two possible reaction paths for the thermal back-conversion of diaryl substituted quadricyclane are identified and it is shown that among the compounds considered the path via the acceptor side is systematically favored. Finally, the present study establishes the basis for high-throughput screening of norbornadiene-quadricyclane compounds as it provides guidelines for the level of accuracy that can be expected for key properties from several different techniques.

Structure-Activity Relationship Studies on a Macrocyclic Agouti-Related Protein (AGRP) Scaffold Reveal Agouti Signaling Protein (ASP) Residue Substitutions Maintain Melanocortin-4 Receptor Antagonist Potency and Result in Inverse Agonist Pharmacology at the Melanocortin-5 Receptor.

PubMed

Ericson, Mark D; Freeman, Katie T; Schnell, Sathya M; Fleming, Katlyn A; Haskell-Luevano, Carrie

2017-10-12

The melanocortin system consists of five reported receptors, agonists from the proopiomelanocortin gene transcript, and two antagonists, agouti-signaling protein (ASP) and agouti-related protein (AGRP). For both ASP and AGRP, the hypothesized Arg-Phe-Phe pharmacophores are on exposed β-hairpin loops. In this study, the Asn and Ala positions of a reported AGRP macrocyclic scaffold (c[Pro-Arg-Phe-Phe-Asn-Ala-Phe-DPro]) were explored with 14-compound and 8-compound libraries, respectively, to generate more potent, selective melanocortin receptor antagonists. Substituting diaminopropionic acid (Dap), DDap, and His at the Asn position yielded potent MC4R ligands, while replacing Ala with Ser maintained MC4R potency. Since these substitutions correlate to ASP loop residues, an additional Phe to Ala substitution was synthesized and observed to maintain MC4R potency. Seventeen compounds also possessed inverse agonist activity at the MC5R, the first report of this pharmacology. These findings are useful in developing molecular probes to study negative energy balance conditions and unidentified functions of the MC5R.

Change in daily energy intake associated with pairwise compositional change in carbohydrate, fat and protein intake among US adults, 1999-2010.

PubMed

An, Ruopeng; Burd, Nicholas A

2015-06-01

To assess the change in daily energy intake associated with pairwise compositional change in carbohydrate, fat and protein intake among US adults stratified by sex, race/ethnicity and weight status. Linear mixture model was performed to estimate the relationship between daily energy intake and macronutrient composition, adjusted for age and alcohol consumption, and accounting for survey design. Study sample from the National Health and Nutrition Examination Survey, 1999-2010 waves. A total of 27 589 US adults aged 20 years and older were included in the study. Dietary macronutrient intake was calculated from 24 h dietary recall and BMI from objectively measured weight/height. Across all population subgroups, substituting protein or carbohydrate for fat and substituting protein for carbohydrate were associated with decreased daily energy intake, with the largest effect resulting from substituting protein for fat. A 1 % increase in the percentage of energy from protein substituted for a 1 % decrease in the percentage of energy from fat was associated with a decrease in daily energy intake of 268.2 (95 % CI 169.0, 367.4) kJ, 289.5 (95 % CI 215.9, 363.2) kJ and 293.7 (95 % CI 210.0, 377.4) kJ among normal-weight (18.5≤BMI, kg/m2<25.0), overweight (25.0≤BMI, kg/m2<30.0) and obese (BMI≥30.0 kg/m2) men, and 177.4 (95 % CI 130.5, 224.3) kJ, 188.7 (95 % CI 139.3, 238.1) kJ and 204.2 (95 % CI 158.2, 250.2) kJ among normal-weight, overweight and obese women, respectively. The relationship between macronutrient composition and daily energy intake varied substantially across sex, race/ethnicity and weight status. Policies promoting higher daily protein intake at the expense of lower fat intake could be effective in reducing total energy intake among US adults.

Structural and electrical properties of Se-hyperdoped Si via ion implantation and flash lamp annealing

NASA Astrophysics Data System (ADS)

Liu, Fang; Prucnal, S.; Yuan, Ye; Heller, R.; Berencén, Y.; Böttger, R.; Rebohle, L.; Skorupa, W.; Helm, M.; Zhou, S.

2018-06-01

We report on the hyperdoping of silicon with selenium obtained by ion implantation followed by flash lamp annealing. It is shown that the degree of crystalline lattice recovery of the implanted layers and the Se substitutional fraction depend on the pulse duration and energy density of the flash. While the annealing at low energy densities leads to an incomplete recrystallization, annealing at high energy densities results in a decrease of the substitutional fraction of impurities. The electrical properties of the implanted layers are well-correlated with the structural properties resulting from different annealing processing.

Diaryl-substituted norbornadienes with red-shifted absorption for molecular solar thermal energy storage.

PubMed

Gray, Victor; Lennartson, Anders; Ratanalert, Phasin; Börjesson, Karl; Moth-Poulsen, Kasper

2014-05-25

Red-shifting the absorption of norbornadienes (NBDs), into the visible region, enables the photo-isomerization of NBDs to quadricyclanes (QCs) to be driven by sunlight. This is necessary in order to utilize the NBD-QC system for molecular solar thermal (MOST) energy storage. Reported here is a study on five diaryl-substituted norbornadienes. The introduced aryl-groups induce a significant red-shift of the UV/vis absorption spectrum of the norbornadienes, and device experiments using a solar-simulator set-up demonstrate the potential use of these compounds for MOST energy storage.

On the climate policy implications of substitutability and flexibility in the economy: An in-depth integrated assessment model diagnostic

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

Craxton, Melanie; Merrick, James; Makridis, Christos

This paper conducts an in-depth model diagnostic exercise for two parameters, 1) the elasticity of substitution between the capital/labour aggregate and the energy aggregate in the Integrated Assessment Model (IAM) MERGE's production function and 2) the rate at which new technologies can be deployed within the energy system. We show that in a more complementary world the model's ability to adjust the carbon intensity of its energy sector is more important whereas in a more substitutable world the ability to expand carbon free technologies is of lesser relative importance. The uncertainty in the literature surrounding the elasticity of substitution parameter,more » its interaction with the mechanisms of technical change, and the associated danger of grounding forward-looking analyses in historically based parameters lend support to the importance of such a diagnostic exercise. Building on work from model intercomparison studies, we investigate whether a given model's choice of strategy is primarily a function of the choice of its parameter values or its structure. As a result, a deeper understanding of what drives model behaviour is beneficial to both modellers and the policymakers who utilise their insights and output.« less

On the climate policy implications of substitutability and flexibility in the economy: An in-depth integrated assessment model diagnostic

DOE PAGES

Craxton, Melanie; Merrick, James; Makridis, Christos; ...

2017-07-12

This paper conducts an in-depth model diagnostic exercise for two parameters, 1) the elasticity of substitution between the capital/labour aggregate and the energy aggregate in the Integrated Assessment Model (IAM) MERGE's production function and 2) the rate at which new technologies can be deployed within the energy system. We show that in a more complementary world the model's ability to adjust the carbon intensity of its energy sector is more important whereas in a more substitutable world the ability to expand carbon free technologies is of lesser relative importance. The uncertainty in the literature surrounding the elasticity of substitution parameter,more » its interaction with the mechanisms of technical change, and the associated danger of grounding forward-looking analyses in historically based parameters lend support to the importance of such a diagnostic exercise. Building on work from model intercomparison studies, we investigate whether a given model's choice of strategy is primarily a function of the choice of its parameter values or its structure. As a result, a deeper understanding of what drives model behaviour is beneficial to both modellers and the policymakers who utilise their insights and output.« less

Hawaii energy strategy project 2: Fossil energy review. Task 2: Fossil energy in Hawaii

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

Breazeale, K.; Yamaguchi, N.D.; Keeville, H.

1993-12-01

In Task 2, the authors establish a baseline for evaluating energy use in Hawaii, and examine key energy and economic indicators. They provide a detailed look at fossil energy imports by type, current and possible sources of oil, gas and coal, quality considerations, and processing/transformation. They present time series data on petroleum product consumption by end-use sector, though they caution the reader that the data is imperfect. They discuss fuel substitutability to identify those end-use categories that are most easily switched to other fuels. They then define and analyze sequential scenarios of fuel substitution in Hawaii and their impacts onmore » patterns of demand. They also discuss energy security--what it means to Hawaii, what it means to neighboring economies, whether it is possible to achieve energy security. 95 figs., 48 tabs.« less

Hybrid Simulation Modeling to Estimate U.S. Energy Elasticities

NASA Astrophysics Data System (ADS)

Baylin-Stern, Adam C.

This paper demonstrates how an U.S. application of CIMS, a technologically explicit and behaviourally realistic energy-economy simulation model which includes macro-economic feedbacks, can be used to derive estimates of elasticity of substitution (ESUB) and autonomous energy efficiency index (AEEI) parameters. The ability of economies to reduce greenhouse gas emissions depends on the potential for households and industry to decrease overall energy usage, and move from higher to lower emissions fuels. Energy economists commonly refer to ESUB estimates to understand the degree of responsiveness of various sectors of an economy, and use estimates to inform computable general equilibrium models used to study climate policies. Using CIMS, I have generated a set of future, 'pseudo-data' based on a series of simulations in which I vary energy and capital input prices over a wide range. I then used this data set to estimate the parameters for transcendental logarithmic production functions using regression techniques. From the production function parameter estimates, I calculated an array of elasticity of substitution values between input pairs. Additionally, this paper demonstrates how CIMS can be used to calculate price-independent changes in energy-efficiency in the form of the AEEI, by comparing energy consumption between technologically frozen and 'business as usual' simulations. The paper concludes with some ideas for model and methodological improvement, and how these might figure into future work in the estimation of ESUBs from CIMS. Keywords: Elasticity of substitution; hybrid energy-economy model; translog; autonomous energy efficiency index; rebound effect; fuel switching.

Advances in Skin Regeneration Using Tissue Engineering.

PubMed

Vig, Komal; Chaudhari, Atul; Tripathi, Shweta; Dixit, Saurabh; Sahu, Rajnish; Pillai, Shreekumar; Dennis, Vida A; Singh, Shree R

2017-04-07

Tissue engineered skin substitutes for wound healing have evolved tremendously over the last couple of years. New advances have been made toward developing skin substitutes made up of artificial and natural materials. Engineered skin substitutes are developed from acellular materials or can be synthesized from autologous, allograft, xenogenic, or synthetic sources. Each of these engineered skin substitutes has their advantages and disadvantages. However, to this date, a complete functional skin substitute is not available, and research is continuing to develop a competent full thickness skin substitute product that can vascularize rapidly. There is also a need to redesign the currently available substitutes to make them user friendly, commercially affordable, and viable with longer shelf life. The present review focuses on providing an overview of advances in the field of tissue engineered skin substitute development, the availability of various types, and their application.

Recycling of plastic: accounting of greenhouse gases and global warming contributions.

PubMed

Astrup, Thomas; Fruergaard, Thilde; Christensen, Thomas H

2009-11-01

Major greenhouse gas (GHG) emissions related to plastic waste recycling were evaluated with respect to three management alternatives: recycling of clean, single-type plastic, recycling of mixed/contaminated plastic, and use of plastic waste as fuel in industrial processes. Source-separated plastic waste was received at a material recovery facility (MRF) and processed for granulation and subsequent downstream use. In the three alternatives, plastic was assumed to be substituting virgin plastic in new products, wood in low-strength products (outdoor furniture, fences, etc.), and coal or fuel oil in the case of energy utilization. GHG accounting was organized in terms of indirect upstream emissions (e.g. provision of energy, fuels, and materials), direct emissions at the MRF (e.g. fuel combustion), and indirect downstream emissions (e.g. avoided emissions from production of virgin plastic, wood, or coal/oil). Combined, upstream and direct emissions were estimated to be roughly between 5 and 600 kg CO(2)-eq. tonne( -1) of plastic waste depending on treatment at the MRF and CO(2) emissions from electricity production. Potential downstream savings arising from substitution of virgin plastic, wood, and energy fuels were estimated to be around 60- 1600 kg CO(2)-eq. tonne( -1) of plastic waste depending on substitution ratios and CO(2) emissions from electricity production. Based on the reviewed data, it was concluded that substitution of virgin plastic should be preferred. If this is not viable due to a mixture of different plastic types and/or contamination, the plastic should be used for energy utilization. Recycling of plastic waste for substitution of other materials such as wood provided no savings with respect to global warming.

Effect of five-membered ring and heteroatom substitution on charge transport properties of perylene discotic derivatives: A theoretical approach

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

Navarro, Amparo, E-mail: anavarro@ujaen.es; Fernández-Liencres, M. Paz; Peña-Ruiz, Tomás

2016-08-07

Density functional theory calculations were carried out to investigate the evolvement of charge transport properties of a set of new discotic systems as a function of ring and heteroatom (B, Si, S, and Se) substitution on the basic structure of perylene. The replacement of six-membered rings by five-membered rings in the reference compound has shown a prominent effect on the electron reorganization energy that decreases ∼0.2 eV from perylene to the new carbon five-membered ring derivative. Heteroatom substitution with boron also revealed to lower the LUMO energy level and increase the electron affinity, therefore lowering the electron injection barrier comparedmore » to perylene. Since the rate of the charge transfer between two molecules in columnar discotic systems is strongly dependent on the orientation of the stacked cores, the total energy and transfer integral of a dimer as a disc is rotated with respect to the other along the stacking axis have been predicted. Aimed at obtaining a more realistic approach to the bulk structure, the molecular geometry of clusters made up of five discs was fully optimized, and charge transfer rate and mobilities were estimated for charge transport along a one dimensional pathway. Heteroatom substitution with selenium yields electron transfer integral values ∼0.3 eV with a relative disc orientation of 25°, which is the preferred angle according to the dimer energy profile. All the results indicate that the tetraselenium-substituted derivative, not synthetized so far, could be a promising candidate among those studied in this work for the fabrication of n-type semiconductors based on columnar discotic liquid crystals materials.« less

Effect of five-membered ring and heteroatom substitution on charge transport properties of perylene discotic derivatives: A theoretical approach.

PubMed

Navarro, Amparo; Fernández-Liencres, M Paz; Peña-Ruiz, Tomás; García, Gregorio; Granadino-Roldán, José M; Fernández-Gómez, Manuel

2016-08-07

Density functional theory calculations were carried out to investigate the evolvement of charge transport properties of a set of new discotic systems as a function of ring and heteroatom (B, Si, S, and Se) substitution on the basic structure of perylene. The replacement of six-membered rings by five-membered rings in the reference compound has shown a prominent effect on the electron reorganization energy that decreases ∼0.2 eV from perylene to the new carbon five-membered ring derivative. Heteroatom substitution with boron also revealed to lower the LUMO energy level and increase the electron affinity, therefore lowering the electron injection barrier compared to perylene. Since the rate of the charge transfer between two molecules in columnar discotic systems is strongly dependent on the orientation of the stacked cores, the total energy and transfer integral of a dimer as a disc is rotated with respect to the other along the stacking axis have been predicted. Aimed at obtaining a more realistic approach to the bulk structure, the molecular geometry of clusters made up of five discs was fully optimized, and charge transfer rate and mobilities were estimated for charge transport along a one dimensional pathway. Heteroatom substitution with selenium yields electron transfer integral values ∼0.3 eV with a relative disc orientation of 25°, which is the preferred angle according to the dimer energy profile. All the results indicate that the tetraselenium-substituted derivative, not synthetized so far, could be a promising candidate among those studied in this work for the fabrication of n-type semiconductors based on columnar discotic liquid crystals materials.

A quantum chemistry study on surface reactivity of pristine and carbon-substituted AlN nanotubes

NASA Astrophysics Data System (ADS)

Mahdaviani, Amir; Esrafili, Mehdi D.; Esrafili, Ali; Behzadi, Hadi

2013-09-01

A density functional theory investigation was performed to predict the surface reactivity of pristine and carbon-substituted (6,0) single-walled aluminum nitride nanotubes (AlNNTs). The properties determined include the electrostatic potentials VS(r) and average local ionization energies ĪS(r) on the surfaces of the investigated tubes. According to computed VS(r) results, the Al/N atoms in edge or cap regions show a different reactivity pattern than those at the middle portion of the tubes. Due to the carbon-substitution at the either Al or N sites of the tubes, the negative regions associated with nitrogen atoms are stronger than before. The prediction of surface reactivity and regioselectivity using average local ionization energies has been verified by atomic hydrogen chemisorption energies calculated for AlNNTs at the B3LYP/6-31 G* level. There is an acceptable correlation between the minima of ĪS(r) and the atomic hydrogen chemisorption energies, demonstrating that ĪS(r) provides an effective means for rapidly and economically assessing the relative reactivities of finite sized AlNNTs.

Comparing the Nutritional Impact of Dietary Strategies to Reduce Discretionary Choice Intake in the Australian Adult Population: A Simulation Modelling Study.

PubMed

Grieger, Jessica A; Johnson, Brittany J; Wycherley, Thomas P; Golley, Rebecca K

2017-05-03

Dietary strategies to reduce discretionary choice intake are commonly utilized in practice, but evidence on their relative efficacy is lacking. The aim was to compare the potential impact on nutritional intake of three strategies to reducing discretionary choices intake in the Australian adult (19-90 years) population. Dietary simulation modelling using data from the National Nutrition and Physical Activity Survey 2011-2012 was conducted ( n = 9341; one 24 h dietary recall). Strategies modelled were: moderation (reduce discretionary choices by 50%, with 0%, 25% or 75% energy compensation); substitution (replace 50% of discretionary choices with core choices); reformulation (replace 50% SFA with unsaturated fats, reduce added sugars by 25%, and reduce sodium by 20%). Compared to the base case (observed) intake, modelled intakes in the moderation scenario showed: -17.3% lower energy (sensitivity analyses, 25% energy compensation -14.2%; 75% energy compensation -8.0%), -20.9% lower SFA (-17.4%; -10.5%), -43.3% lower added sugars (-41.1%; -36.7%) and 17.7% lower sodium (-14.3%; -7.5%). Substitution with a range of core items, or with fruits, vegetables and core beverages only, resulted in similar changes in energy intake (-13.5% and -15.4%), SFA (-17.7% and -20.1%), added sugars (-42.6% and -43%) and sodium (-13.7% and -16.5%), respectively. Reformulating discretionary choices had minimal impact on reducing energy intake but reduced SFA (-10.3% to -30.9%), added sugars (-9.3% to -52.9%), and alcohol (-25.0% to -49.9%) and sodium (-3.3% to -13.2%). The substitution and reformulation scenarios minimized negative changes in fiber, protein and micronutrient intakes. While each strategy has strengths and limitations, substitution of discretionary choices with core foods and beverages may optimize the nutritional impact.

4D-π-1A type β-substituted ZnII-porphyrins: ideal green sensitizers for building-integrated photovoltaics.

PubMed

Covezzi, A; Orbelli Biroli, A; Tessore, F; Forni, A; Marinotto, D; Biagini, P; Di Carlo, G; Pizzotti, M

2016-10-18

Two novel green β-substituted Zn II -porphyrins, G1 and G2, based on a 4D-π-1A type substitution pattern have been synthesized. Their enhanced push-pull character, by reduction of H-L energy gaps, promotes broadening and red-shifting of absorption bands. The effective synthetic pathway and the remarkable spectroscopic properties make G2 ideal for BIPV application.

Molecular Orbital Based Design Guidelines for Hypergolic Energetic Ionic Liquids

DTIC Science & Technology

2015-01-01

energy content of the anion must also be taken into account in the design strategy ; substitution should be carried out in such a way that does not...substitution strategy . So far in the litera- ture, HP (with energy gap similar to DCA) is the lowest DHf anion (661.9 kJmol1) for which EIL hypergolicity...T. Nakajima, Y. Honda , O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts

Effects of K and Ca doping on twin boundary energy of cupperate superconductors

NASA Astrophysics Data System (ADS)

Khoshnevisan, Bahram; Mohammadi, Mahnaz

2016-04-01

Ab-initio calculations under GGA approximation have been employed to find out the effect Ba substitution by K and Ca on the structural and electronic properties twined and untwined YBCO system. In this regard, the twin boundary energy, γ, and impact of the substitution on the boundary's charge distribution have been of special consideration. Our results show that despite the structural changes the presence of K (Ca) modifies substantially density of levels at the Fermi level, which could be responsible for empirical reports of decreasing the critical temperature (Tc) by increasing the K(Ca) content. Although, the K doping reduces the γ value in YBa2-xKxCu3O7 system, after calcium doping it remains more or less unchanged. In addition, reduction of the carrier density occurs at twin boundary in CuO2 layer for the substituted system with respect to the untwined YBCO system. Our results would be noticeable in conjunction with the experimentally reported twinned and alkali substituted superconductive properties of the YBCO samples.

Measurement of a linear free energy relationship one molecule at a time

PubMed Central

Rao, B. V.; Kwon, K.-Y.; Liu, A.; Bartels, L.

2004-01-01

A systematic study of the dehydrogenation of substituted thiophenols by controlled charge injection from the tip of a scanning tunneling microscope (STM) reveals a pronounced dependence of the reaction yield on the position and the chemical nature of the substituent. We evaluate the dehydrogenation rate of para-halo-substituted species within a linear free energy relationship, namely the Hammett equation. The resultant ρ value of 1.4 can faithfully predict the reaction rates of molecules that are meta-halo-substituted or para-methyl-substituted. The positive sign of ρ suggests a negatively charged transition state at the core of the STM-induced process, and the magnitude of the ρ value indicates that the presence of the substrate does not preclude substantial substituent effects. The applicability of the Hammett equation to single-molecule chemistry offers facile prediction of the rate of STM-based single-molecule chemistry in a field, which so far has been addressed by focusing on involved quantum-mechanical modeling of its underlying processes. PMID:15601774

Measurement of a linear free energy relationship one molecule at a time.

PubMed

Rao, B V; Kwon, K-Y; Liu, A; Bartels, L

2004-12-28

A systematic study of the dehydrogenation of substituted thiophenols by controlled charge injection from the tip of a scanning tunneling microscope (STM) reveals a pronounced dependence of the reaction yield on the position and the chemical nature of the substituent. We evaluate the dehydrogenation rate of para-halo-substituted species within a linear free energy relationship, namely the Hammett equation. The resultant rho value of 1.4 can faithfully predict the reaction rates of molecules that are meta-halo-substituted or para-methyl-substituted. The positive sign of rho suggests a negatively charged transition state at the core of the STM-induced process, and the magnitude of the rho value indicates that the presence of the substrate does not preclude substantial substituent effects. The applicability of the Hammett equation to single-molecule chemistry offers facile prediction of the rate of STM-based single-molecule chemistry in a field, which so far has been addressed by focusing on involved quantum-mechanical modeling of its underlying processes.

Dipole moment and solvatochromism of benzoic acid liquid crystals: Tuning the dipole moment and molecular orbital energies by substituted Au under external electric field

NASA Astrophysics Data System (ADS)

Sıdır, Yadigar Gülseven; Sıdır, İsa; Demiray, Ferhat

2017-06-01

The optical absorption and steady-state fluorescence spectra of 4-heptyloxybenzoic acid (4hoba), 4-octyloxybenzoic acid (4ooba) and 4-nonyloxybenzoic acid (4noba) liquid crystals have been measured in a series of different polarity organic solvents. The ground state (μg) and excited state (μe) dipole moments of the monomeric and dimeric 4-alkyloxybenzoic acid liquid crystals have been obtained by means of different solvatochromic shift methods. HOMO-LUMO gaps (HLG) and dipole moments have been tuned by applying external electric (EF) field on monomer, dimer and Au substituted monomer and dimer liquid crystal structures. By applying external electric field, Au substituted monomer liquid crystals display semiconductor character, while Au substituted dimer liquid crystals gain metallic character under E = 0.04 V/Å. Eventuated specific and non-specific interactions between solvent and solute in solvent medium have been expounded by using LSER (Linear Solvation Energy Relationships).

Molecular docking and structural analysis of non-opioid analgesic drug acemetacin with halogen substitution: A DFT approach

NASA Astrophysics Data System (ADS)

Leenaraj, D. R.; Manimaran, D.; Joe, I. Hubert

2016-11-01

Acemetacin is a non-opioid analgesic which belongs to the class, the non-steroidal anti-inflammatory drug. The bioactive conformer was identified through potential energy surface scan studies. Spectral features of acemetacin have been probed by the techniques of Fourier transform infrared, Raman and Nuclear magnetic resonance combined with density functional theory calculations at the B3LYP level with 6-311 + G(d,p) basis set. The detailed interpretation of vibrational spectral assignments has been carried out on the basis of potential energy distribution method. Geometrical parameters reveal that the carbonyl substitution in between chlorophenyl and indole ring leads to a significant loss of planarity. The red-shifted Cdbnd O stretching wavenumber describe the conjugation between N and O atoms. The shifted Csbnd H stretching wavenumbers of Osbnd CH3 and Osbnd CH2 groups depict the back-donation and induction effects. The substitution of halogen atoms on the title molecule influences the charge distribution and the geometrical parameters. Drug activity and binding affinity of halogen substitution in title molecule with target protein were undertaken by molecular docking study. This study enlightens the effects of bioefficiency due to the halogen substitution in the molecule.

The substitution reaction of (CNC)Fe-2N₂ with CO.

PubMed

Liu, Hongyan; Liu, Shuangshuang; Zhang, Xiang

2013-06-01

The substitution mechanism of two N₂ ligands in (CNC)Fe-2N₂ replaced by CO was studied theoretically at the B3LYP/LACVP* level. Both SN1 and SN₂ mechanisms were considered. The calculated results for the gas phase suggested that: 1) in SN1 mechanism, N₂ elimination, which involves S₀-T₁ PESs crossing, is the rate control step for both substitution stages. The barrier heights are 9.7 kcal mol(-1) and 13.05 kcal mol(-1), respectively. 2) In SN2 mechanism, the calculated barrier heights on LS PES are respectively 13.7 and 19.83 kcal mol(-1) for the two substitution steps, but S₀-T₁ PESs crossing lowers the two barriers to 10.7 and 15.7 kcal mol(-1), respectively. 3) Inclusion of solvation effect of THF by PCM model, the relative energies of all the key species (including minima, transition states and S₀-T₁ crossing points) do not have great difference from their gas phase relative energies. Considering that for each substitution step, SN1 barrier heights is slightly smaller than SN2 barrier, SN1 mechanism seems to be slightly preferable to SN2 mechanism.

Transition metal decorated graphene-like zinc oxide monolayer: A first-principles investigation

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

Lei, Jie; School of Science, Qilu University of Technology, Jinan, Shandong 250353; Xu, Ming-Chun

Transition metal (TM) atoms have been extensively employed to decorate the two-dimensional materials, endowing them with promising physical properties. Here, we have studied the adsorption of TM atoms (V, Cr, Mn, Fe, and Co) on graphene-like zinc oxide monolayer (g-ZnO) and the substitution of Zn by TM using first-principles calculations to search for the most likely configurations when TM atoms are deposited on g-ZnO. We found that when a V atom is initially placed on the top of Zn atom, V will squeeze out Zn from the two-dimensional plane then substitute it, which is a no barrier substitution process. Formore » heavier elements (Cr to Co), although the substitution configurations are more stable than the adsorption ones, there is an energy barrier for the adsorption-substitution transition with the height of tens to hundreds meV. Therefore, Cr to Co prefers to be adsorbed on the hollow site or the top of oxygen, which is further verified by the molecular dynamics simulations. The decoration of TM is revealed to be a promising approach in terms of tuning the work function of g-ZnO in a large energy range.« less

Transition metal decorated graphene-like zinc oxide monolayer: A first-principles investigation

NASA Astrophysics Data System (ADS)

Lei, Jie; Xu, Ming-Chun; Hu, Shu-Jun

2015-09-01

Transition metal (TM) atoms have been extensively employed to decorate the two-dimensional materials, endowing them with promising physical properties. Here, we have studied the adsorption of TM atoms (V, Cr, Mn, Fe, and Co) on graphene-like zinc oxide monolayer (g-ZnO) and the substitution of Zn by TM using first-principles calculations to search for the most likely configurations when TM atoms are deposited on g-ZnO. We found that when a V atom is initially placed on the top of Zn atom, V will squeeze out Zn from the two-dimensional plane then substitute it, which is a no barrier substitution process. For heavier elements (Cr to Co), although the substitution configurations are more stable than the adsorption ones, there is an energy barrier for the adsorption-substitution transition with the height of tens to hundreds meV. Therefore, Cr to Co prefers to be adsorbed on the hollow site or the top of oxygen, which is further verified by the molecular dynamics simulations. The decoration of TM is revealed to be a promising approach in terms of tuning the work function of g-ZnO in a large energy range.

Life-cycle energy production and emissions mitigation by comprehensive biogas-digestate utilization.

PubMed

Chen, Shaoqing; Chen, Bin; Song, Dan

2012-06-01

In the context of global energy shortages and climate change, developing biogas plants with links to agricultural system has become an important strategy for cleaner rural energy and renewable agriculture. In this study, a life-cycle energy and environmental assessment was performed for a biogas-digestate utilization system in China. The results suggest that biogas utilization (heating, illumination, and fuel) and comprehensive digestate reuse are of equal importance in the total energy production of the system, and they also play an important role in systemic greenhouse gas mitigation. Improvement can be achieved in both energy production and emissions mitigation when the ratio of the current three biogas utilization pathways is adjusted. Regarding digestate reuse, a tradeoff between energy and environmental performance can be obtained by focusing on the substitution for top-dressing, base fertilizers, and the application to seed soaking. Copyright © 2012 Elsevier Ltd. All rights reserved.

Energy transition in transport sector from energy substitution perspective

NASA Astrophysics Data System (ADS)

Sun, Wangmin; Yang, Xiaoguang; Han, Song; Sun, Xiaoyang

2017-10-01

Power and heating generation sector and transport sector contribute a highest GHG emissions and even air pollutions. This paper seeks to investigate life cycle costs and emissions in both the power sector and transport sector, and evaluate the cost-emission efficient (costs for one unit GHG emissions) of the substitution between new energy vehicles and conventional gasoline based vehicles under two electricity mix scenarios. In power sector, wind power and PV power will be cost comparative in 2030 forecasted with learning curve method. With high subsidies, new energy cars could be comparative now, but it still has high costs to lower GHG emissions. When the government subsidy policy is reversible, the emission reduction cost for new energy vehicle consumer will be 900/ton. According to the sensitive analysis, the paper suggests that the government implement policies that allocate the cost to the whole life cycle of energy production and consumption related to transport sector energy transition and policies that are in favor of new energy vehicle consumers but not the new energy car producers.

Singlet Fission and Excimer Formation in Disordered Solids of Alkyl-Substituted 1,3-Diphenylisobenzofurans

DOE PAGES

Dron, Paul I.; Michl, Josef; Johnson, Justin C.

2017-10-16

Here, we describe the preparation and excited state dynamics of three alkyl derivatives of 1,3-diphenylisobenzofuran (1) in both solutions and thin films. The substitutions are intended to disrupt the slip-stacked packing observed in crystals of 1 while maintaining the favorable energies of singlet and triplet for singlet fission (SF). All substitutions result in films that are largely amorphous as judged by the absence of strong X-ray diffraction peaks.

Evaluation of the energy budget method of determining evaporation at Williams Lake, Minnesota, using alternative instrumentation and study approaches

USGS Publications Warehouse

Rosenberry, D.O.; Sturrock, A.M.; Winter, T.C.

1993-01-01

Best estimates of evaporation at Williams Lake, north central Minnesota, were determined by the energy budget method using optimum sensors and optimum placement of sensors. These best estimates are compared with estimates derived from using substitute data to determine the effect of using less accurate sensors, simpler methods, or remotely measured data. Calculations were made for approximately biweekly periods during five open water seasons. For most of the data substitutions that affected the Bowen ratio, new values of evaporation differed little from best estimates. The three data substitution methods that caused the largest deviations from the best evaporation estimates were (1) using changes in the daily average surface water temperature as an indicator of the lake heat storage term, (2) using shortwave radiation, air temperature, and atmospheric vapor pressure data from a site 110 km away, and (3) using an analog surface water temperature probe. Recalculations based on these data substitutions resulted in differences from the best estimates as much as 89%, 21%, and 10%, respectively. The data substitution method that provided evaporation values that most closely matched the best estimates was measurement of the lake heat storage term at one location in the lake, rather than at 16 locations. Evaporation values resulting from this substitution method usually were within 2% of the best estimates.

QuEST: Qualifying Environmentally Sustainable Technologies, Volume 5

NASA Technical Reports Server (NTRS)

Lewis, Pattie

2010-01-01

This edition of the QuEST newsletter contains brief articles that discuss the NASA Technology Evaluation for Environmental Risk Mitigation (TEERM) program, and the importance of collaboration, efforts in materials management and substitution for coatings for launch structures, Low volatile organic compound (VOC) Coatings Field Testing, Non-Chrome Coating Systems, Life Cycle Corrosion Testing, Lead-Free Electronics Testing and Corn Based Depainting and efforts in Pollution Control in the area of Hypergolic Propellant Destruction Evaluation, efforts in development of alternative energy in particular Hydrogen Sensors, Energy and Water Management, and efforts in remediation in the removal of Polychlorinated Biphenyl (PCB) contamination

Coal and peat in the sub-Saharan region of Africa: alternative energy options?

USGS Publications Warehouse

Weaver, J.N.; Landis, E.R.

1990-01-01

Coal and peat are essentially unused and in some cases unknown in sub-Saharan Africa. However, they might comprise valuable alternative energy sources in some or all of the developing nations of the region. The 11 countries considered in this appraisal reportedly contain coal and peat. On the basis of regional geology, another five countries might also contain coal-bearing rocks. If the resource potential is adequate, coal and peat might be utilized in a variety of ways including substituting for fuelwood, generating electricity, supplying process heat for local industry and increasing agricultural productivity. -from Author

Soy-enhanced lunch acceptance by preschoolers.

PubMed

Endres, Jeannette; Barter, Sharon; Theodora, Perseli; Welch, Patricia

2003-03-01

To evaluate acceptance of soy-enhanced compared with traditional menus by preschool children. Soy-enhanced foods were substituted on a traditional cycle menu, and the amount eaten, energy, and nutrient values for traditional and soy-enhanced lunches were compared. A traditional three-week cycle menu, using the Child and Adult Care Food Program (CACFP) meal pattern guidelines, was used to develop a comparable soy-enhanced menu. Traditional and soy-enhanced lunches were randomly assigned to respective days. Foods were portioned onto individual plates using standardized measuring utensils. Individual plate waste techniques were used to collect food waste. Subjects/setting Participants were preschool children, three to six years of age and of white and Hispanic origin, attending a part-day Head Start program. Statistical analyses performed Analysis of covariance was used to adjust lunch and food intakes for differences in average amounts of foods served. The Nutrient Data System was used to calculate energy and nutrient content of lunches. Analysis of variance was used to calculate differences in amounts eaten, energy values, and nutrient values of traditional and soy-enhanced lunches and foods. Data analyses were performed with the Statistical Analysis Software (version 8.0, 1999, SAS Institute, Cary, NC). Soy-enhanced foods were successfully substituted for 23 traditional foods included in the cycle menus. Soy-enhanced foods tended to be higher in energy, protein, and iron. Traditional lunches tended to be higher in fat, saturated fat, and vitamin A. Consumption was significantly less for energy, protein, fiber, and iron from foods eaten from traditional compared with soy-enhanced lunch menus. Applications/conclusions Acceptance of soy-enhanced lunches was shown because there were no significant differences in the average amount eaten (grams per meal) between traditional and soy-enhanced lunches. Preschool programs can substitute soy-enhanced for traditional foods, which will add variety to the diet without sacrificing taste, energy, or nutrient value. The fat and energy content of the lunches was higher than recommended, and soy-enhanced foods were not always lower in fat. There is a need for the food industry and foodservice personnel to address the energy and fat content of all foods served in lunches to preschool children because a few extra calories added to the daily intakes can contribute to weight gain.

Opportunity and prospect analysis of RES utilization for sustainable development of Ekaterinburg city in Russia

NASA Astrophysics Data System (ADS)

Volkov, A.; Aristova, A.

2017-06-01

Recently megalopolises have become centres of economy development worldwide. Gradual growth in energy consumption and thereafter - enormous power production and delivery to sustain metropolis’ needs entailed, rapid increase in emissions of hazardous substances in quantities, no longer tolerable for secure residence in majority of these cities. Ekaterinburg, is one of them. In order to abridge harmful pollution in Ekaterinburg and further centralize economic importance of the city, this paper proposes to implement the concept of urban sustainable development/ref. / by introducing alternative energy sources, which would progressively displace traditional fossil fuels. A number of actual cases, where the concept was successfully implemented, were studied and analysed to demonstrate how different shares of renewables can become effective substitutes to conventional energy sources in the cities strongly dependent on them: 1. Energy strategy of Pecs (Hungary); 2. International low carbon city (ILCC) project (Shenzhen, China); 3. Electric power system template of Tangshan city (China). Further, regional environmental and economic specifics of Ekaterinburg were studied to understand power consumption needs and energy generation possibilities, which led authors to conclude on the alternative energy sources feasibility, plot specific flow chart for RES implementation in Ekaterinburg’s power network and outline recommendations for future works.

ETA-MACRO: A user's guide

NASA Astrophysics Data System (ADS)

Manne, A. S.

1981-02-01

The ETA-MACRO model is designed to estimate the extent of two way linkage between the energy sector and the balance of the economy. It represents a merger between ETA (a process analysis for energy technology assessment) together with a macroeconomic growth model providing for substitution between capital, labor, and energy inputs. The ETA-MACRO allows explicitly for: (1) energy economy interactions; (2) cost effective conservation; (3) interfuel substitution, and (4) new supply technologies, each with its own difficulties and uncertainties on dates and rates of introduction. This user's guide includes an overview of the model, an illustrative application to long term US energy projections, and technical descriptions of the macro and ETA submodels. It also includes an analysis of how market penetration rates may be related to the profitability of new technologies. Finally, the appendices provide a detailed guide to the computer implementation.

10 CFR 490.702 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Definitions. 490.702 Section 490.702 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.702...— Biodiesel means a diesel fuel substitute produced from nonpetroleum renewable resources that meets the...

10 CFR 490.702 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Definitions. 490.702 Section 490.702 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.702...— Biodiesel means a diesel fuel substitute produced from nonpetroleum renewable resources that meets the...

10 CFR 490.702 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Definitions. 490.702 Section 490.702 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.702...— Biodiesel means a diesel fuel substitute produced from nonpetroleum renewable resources that meets the...

10 CFR 490.702 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Definitions. 490.702 Section 490.702 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.702...— Biodiesel means a diesel fuel substitute produced from nonpetroleum renewable resources that meets the...

10 CFR 490.702 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Definitions. 490.702 Section 490.702 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Biodiesel Fuel Use Credit § 490.702...— Biodiesel means a diesel fuel substitute produced from nonpetroleum renewable resources that meets the...

Using Theoretical Descriptions in Structure Activity Relations. 3. Electronic Descriptors

DTIC Science & Technology

1988-08-01

Activity Relationships (QSAR) have been used successfully in the past to develop predictive equations for several biological and physical properties...Linear Free Energy Relationships (,FF.3) and is based on work by Hammet in which he derived electronic descriptors for the dissociation of substituted...structure of a compound and its activity in a system. Several different structural descriptors have been used in QSAR equations . These range from

Possibilities and limits concerning the substitution of oil by nuclear energy and coal

NASA Astrophysics Data System (ADS)

Penczynski, P.

1981-05-01

The energy situation in West Germany is discussed. About 96% of the crude oil consumed has to be imported. It is pointed out that this situation together with general developments concerning the diminishing petroleum resources of the world will make it necessary to replace the oil with other energy carriers. Coal resources in West Germany are large enough to last for a few hundred years. However, the consumption of coal as energy carrier should not exceed certain limits in connection with ecological considerations. Uranium as raw material for nuclear energy must also be imported. However, the quantities involved are very small, in connection with the high-energy density of the material. Consequently, a storage of uranium corresponding to a large amount of energy does not present any problems. Various approaches for replacing oil are discussed, taking into account the heat pump, possibilities for storing electric energy generated during the night, automobiles operated with electric energy, energy carriers obtained from coal, and the direct use of coal.

Understanding the magnetoelastic behavior of pure and Co substituted GdNi

NASA Astrophysics Data System (ADS)

Paudyal, Durga; Mudryk, Y.; Pecharsky, V. K.; Gschneidner, K. A., Jr.

Total-energy calculations employing local spin density approximation including Hubbard U (onsite electron correlation) parameter and temperature and magnetic field dependent x-ray diffraction experiments show large anisotropic shifts in lattice parameters and a giant linear magnetostriction without a structural transformation and a negligible volume magnetostriction in GdNi. In agreement with the magnetization and heat-capacity experiments, the total-energy and band splitting results confirm that the anisotropic shape changes in GdNi are associated with the second-order ferromagnetic to paramagnetic transformation. When the band splitting due to the ferromagnetic ordering of the 4 fmoments increases, the concomitant anisotropic changes in the lattice minimize the total free energy of the crystal indicating an unusual interplay between magnetism and crystal structure. The positive formation energy at 0K and the nature of the density of states at the Fermi level confirm an unstable equiatomic Gd compound when Ni is fully substituted by Co. However, the enhanced effective exchange interactions with small Co substitutions increase the Curie temperature without losing the chemical stability. The Ames Laboratory is operated for the US DOE by Iowa State. This work was supported by the DOE, Office of Basic Energy Sciences, Materials Sciences Division under Contract No. DE-AC02-07CH11358.

Sugar substitutes: their energy values, bulk characteristics, and potential health benefits.

PubMed

Levin, G V; Zehner, L R; Saunders, J P; Beadle, J R

1995-11-01

Restriction of dietary energy extends life and reduces incidences of disease in animals. These benefits would likely extend to humans. However, diet restriction in animals imposes reductions of 30-50% in food intake, which is probably unacceptable to humans. Low-energy sweeteners used in beverages offer minor reductions in energy intake. However, they lack the bulk required for baked goods and other sugar-rich foods. Full-bulk sweeteners providing about one-half the energy of sugar are under development for such uses. Laxation limits their acceptable dose. Even within such limitations, they can help achieve the health benefits for humans indicated by diet restriction. D-Tagatose, a new candidate sweetener, is nearly as sweet as sucrose and has the bulk of sucrose, yet provides zero available energy. We discuss its potential contribution to human diet restriction along with its specific effect in delaying the aging effects of glycosylation.

Ab initio design of nanostructures for solar energy conversion: a case study on silicon nitride nanowire.

PubMed

Pan, Hui

2014-01-01

Design of novel materials for efficient solar energy conversion is critical to the development of green energy technology. In this work, we present a first-principles study on the design of nanostructures for solar energy harvesting on the basis of the density functional theory. We show that the indirect band structure of bulk silicon nitride is transferred to direct bandgap in nanowire. We find that intermediate bands can be created by doping, leading to enhancement of sunlight absorption. We further show that codoping not only reduces the bandgap and introduces intermediate bands but also enhances the solubility of dopants in silicon nitride nanowires due to reduced formation energy of substitution. Importantly, the codoped nanowire is ferromagnetic, leading to the improvement of carrier mobility. The silicon nitride nanowires with direct bandgap, intermediate bands, and ferromagnetism may be applicable to solar energy harvesting.

Substitutional and interstitial oxygen in wurtzite GaN

NASA Astrophysics Data System (ADS)

Wright, A. F.

2005-11-01

Density-functional theory was used to compute energy-minimum configurations and formation energies of substitutional and interstitial oxygen (O) in wurtzite GaN. The results indicate that O substituted at a N site (ON) acts as a single donor with the ionized state (ON+1) being the most stable O state in p-type GaN. In n-type GaN, interstitial O (OI) is predicted to be a double acceptor and O substituted at a Ga site (OGa) is predicted to be a triple acceptor. The formation energies of these two species are comparable to that of ON in n-type GaN and, as such, they should form and compensate the ON donors. The extent of compensation was estimated for both Ga-rich and N-rich conditions with a total O concentration of 1017cm-3. Ga-rich conditions yielded negligible compensation and an ON concentration in excess of 9.9×1016cm-3. N-rich conditions yielded a 25% lower ON concentration, due to the increased stability of OI and OGa relative to ON, and moderate compensation. These findings are consistent with experimental results indicating that O acts as a donor in GaN(O). Complexes of ON with the Mg acceptor and OI with the Si donor were examined. Binding energies for charge-conserving reactions were ⩾0.5eV, indicating that these complexes can exist in equilibrium at room temperature. Complexes of ON with the Ga vacancy in n-type GaN were also examined and their binding energies were 1.2 and 1.4eV, indicating that appreciable concentrations can exist in equilibrium even at elevated temperatures.

Band structure modification of the thermoelectric Heusler-phase TiFe2Sn via Mn substitution.

PubMed

Zou, Tianhua; Jia, Tiantian; Xie, Wenjie; Zhang, Yongsheng; Widenmeyer, Marc; Xiao, Xingxing; Weidenkaff, Anke

2017-07-19

Doping (or substitution)-induced modification of the electronic structure to increase the electronic density of states (eDOS) near the Fermi level is considered as an effective strategy to enhance the Seebeck coefficient, and may consequently boost the thermoelectric performance. Through density-functional theory calculations of Mn-substituted TiFe 2-x Mn x Sn compounds, we demonstrate that the d-states of the substituted Mn atoms induce a strong resonant level near the Fermi energy. Our experimental results are in good agreement with the calculations. They show that Mn substitution results in a large increase of the Seebeck coefficient, arising from an enhanced eDOS in Heusler compounds. The results prove that a proper substitution position and element selection can increase the eDOS, leading to a higher Seebeck coefficient and thermoelectric performance of ecofriendly materials.

Corrigendum to ;Dipole moment and solvatochromism of benzoic acid liquid crystals: Tuning the dipole moment and molecular orbital energies by substituted Au under external electric field; [J. Mol. Struct. 1137 (2017) 440-452

NASA Astrophysics Data System (ADS)

Sıdır, Yadigar Gülseven; Sıdır, İsa; Demiray, Ferhat

2017-08-01

The authors regret to inform that three references in the article titled ;Dipole moment and solvatochromism of benzoic acid liquid crystals: Tuning the dipole moment and molecular orbital energies by substituted Au under external electric field; are not given in the manuscript. This is purely an oversight mistake. The references are as shown in this correction. The authors would like to apologize for any inconvenience caused.

Synthesis, antimicrobial activity and advances in structure-activity relationships (SARs) of novel tri-substituted thiazole derivatives.

PubMed

Reddy, Guda Mallikarjuna; Garcia, Jarem Raul; Reddy, Vemulapati Hanuman; de Andrade, Ageo Meier; Camilo, Alexandre; Pontes Ribeiro, Renan Augusto; de Lazaro, Sergio Ricardo

2016-11-10

Trisubstituted thiazoles were synthesized and studied for their antimicrobial activity and supported by theoretical calculations. In addition, MIC, MBC and MFC were also tested. Moreover, the present study was analyzed to scrutinize comprehensive structure-activity relationships. In fact, LUMO orbital energy and orbital orientation was reliable to explain their antibacterial and antifungal assay. Amongst the tested compounds, tri-methyl-substituted thiazole compound showed higher antimicrobial activity and low MIC value due to highest LUMO energy. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

7 CFR 4280.144 - Transfer of lenders.

Code of Federal Regulations, 2011 CFR

2011-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Renewable Energy Systems and Energy... than the loan approval official who may approve the substitution of a new eligible lender. ...

7 CFR 4280.144 - Transfer of lenders.

Code of Federal Regulations, 2010 CFR

2010-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Renewable Energy Systems and Energy... than the loan approval official who may approve the substitution of a new eligible lender. ...

Alkylation effects on the energy transfer of highly vibrationally excited naphthalene.

PubMed

Hsu, Hsu Chen; Tsai, Ming-Tsang; Dyakov, Yuri A; Ni, Chi-Kung

2011-11-04

The energy transfer of highly vibrationally excited isomers of dimethylnaphthalene and 2-ethylnaphthalene in collisions with krypton were investigated using crossed molecular beam/time-of-flight mass spectrometer/time-sliced velocity map ion imaging techniques at a collision energy of approximately 300 cm(-1). Angular-resolved energy-transfer distribution functions were obtained directly from the images of inelastic scattering. The results show that alkyl-substituted naphthalenes transfer more vibrational energy to translational energy than unsubstituted naphthalene. Alkylation enhances the V→T energy transfer in the range -ΔE(d)=-100~-1500 cm(-1) by approximately a factor of 2. However, the maximum values of V→T energy transfer for alkyl-substituted naphthalenes are about 1500~2000 cm(-1), which is similar to that of naphthalene. The lack of rotation-like wide-angle motion of the aromatic ring and no enhancement in very large V→T energy transfer, like supercollisions, indicates that very large V→T energy transfer requires special vibrational motions. This transfer cannot be achieved by the low-frequency vibrational motions of alkyl groups. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recognition of anions using urea and thiourea substituted calixarenes: A density functional theory study of non-covalent interactions

NASA Astrophysics Data System (ADS)

Athar, Mohd; Lone, Mohsin Y.; Jha, Prakash C.

2018-02-01

Designing of new calixarene receptors for the selective binding of anions is an age-old concept; even though expected outcomes from this field are at premature stage. Herein, we have performed quantum chemical calculations to provide structural basis of anion binding with urea and thiourea substituted calixarenes (1, 2, and 3). In particular, spherical halides (F-, Cl-, Br-) and linear anions (CN-, N3-, SCN-) were modelled for calculating binding energies with receptor 1, 2 and 3 followed by their marked IR vibrations; taking the available experimental information into account. We found that the thiourea substitutions have better capability to stabilize the anions. Results have suggested that the structural behaviour of macrocyclic motifs were responsible for displaying the anion binding potentials. Moreover, second order "charge transfer" interactions of n-σ∗NH and n-σ∗OH type along the H-bond axis played critical role in developing hydrogen bonds. The present work also examines the role of non-covalent interactions (NCI) and their effects on thermodynamic and chemical-reactivity descriptors.

Trade-off results and preliminary designs of Near-Term Hybrid Vehicles

NASA Technical Reports Server (NTRS)

Sandberg, J. J.

1980-01-01

Phase I of the Near-Term Hybrid Vehicle Program involved the development of preliminary designs of electric/heat engine hybrid passenger vehicles. The preliminary designs were developed on the basis of mission analysis, performance specification, and design trade-off studies conducted independently by four contractors. THe resulting designs involve parallel hybrid (heat engine/electric) propulsion systems with significant variation in component selection, power train layout, and control strategy. Each of the four designs is projected by its developer as having the potential to substitute electrical energy for 40% to 70% of the petroleum fuel consumed annually by its conventional counterpart.

Cu1–xFexO: hopping transport and ferromagnetism

PubMed Central

Nasir, Mohd.; Islam, Rakibul; Ahmed, Md. A; Ayaz, Saniya; Kumar, Gautham; Kumar, Sunil; Prajapat, C. L.; Roussel, Frederick; Biring, Sajal

2017-01-01

Single phase, sol–gel prepared Cu1–xFexO (0 ≤ x ≤ 0.125) powders are characterized in terms of structural, electronic and magnetic properties. Using dielectric and magnetic studies we investigate the coupling of electron and spin. The electrical conductivities and activation energies are studied with increasing Fe content. Modelling of experimental conductivity data emphasizes a single hopping mechanism for all samples except x = 0.125, which have two activation energies. Hole doping is confirmed by confirming a majority Fe3+ substitution of Cu2+ in CuO from X-ray photoelectron spectroscopy studies (XPS). Such a substitution results in stabilized ferromagnetism. Fe substitution introduces variation in coercivity as an intrinsic magnetic property in Fe-doped CuO, and not as a secondary impurity phase. PMID:28989741

Tax reform and energy in the Philippines economy: A general equilibrium computation

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

Boyd, R.G.; Doroodian, K.; Udomvaech, P.

1994-12-31

This paper examines how energy tax cuts, offset with income tax increases, affect production, consumption, and total welfare in the Philippines economy. Our results show that energy tax cuts expand the energy and nonmetal mining sectors, but decrease output in the manufacturing, agricultural, and metal mining sectors. Consumption of all goods and services combined increases as the amount of energy tax reduction increases. Our welfare results, however, are mixed. While the welfare of the mid- and high-income levels increases, that of the lowest income level decreases. These results are robust with respect to changes in the elasticity of substitution inmore » energy production as well as the elasticity of substitution in consumer demand. From the standpoint of economic efficiency, a policy such as this would enhance growth and aggregate income. From an equity standpoint, however, this policy is highly regressive in spite of the fact that the richest households pay proportionately more to finance the energy tax reduction. 18 refs., 10 tabs.« less

Hydro and geothermal electricity as an alternative for industrial petroleum consumption in Costa Rica

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

Mendis, M.; Park, W.; Sabadell, A.

This report assesses the potential for substitution of electricity for petroleum in the industrial/agro-industrial sector of Costa Rica. The study includes a preliminary estimate of the process energy needs in this sector, a survey of the principal petroleum consuming industries in Costa Rica, an assessment of the electrical technologies appropriate for substitution, and an analysis of the cost trade offs of alternative fuels and technologies. The report summarizes the total substitution potential both by technical feasibility and by cost effectiveness under varying fuel price scenarios and identifies major institutional constraints to the introduction of electric based technologies. Recommendations to themore » Government of Costa Rica are presented. The key to the success of a Costa Rican program for substitution of electricity for petroleum in industry rests in energy pricing policy. The report shows that if Costa Rica Bunker C prices are increased to compare equitably with Caribbean Bunker C prices, and increase at 3 percent per annum relative to a special industrial electricity rate structure, the entire substitution program, including both industrial and national electric investment, would be cost effective. The definition of these pricing structures and their potential impacts need to be assessed in depth.« less

Enhanced O-2 Selectivity versus N-2 by Partial Metal Substitution in Cu-BTC

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

Sava Gallis, Dorina F.; Parkes, Marie V.; Greathouse, Jeffery A.

2015-03-24

Here, we describe the homogeneous substitution of Mn, Fe, and Co at various levels into a prototypical metal organic framework (MOP), namely Cu-BTC (HKUST-1), and the effect of that substitution on preferential gas sorption. Using a combination of density functional theory (DFT) calculations, postsynthetic metal substitutions, materials characterization, and gas sorption testing, we demonstrate that the identity of the metal ion has a quantifiable effect on their oxygen and nitrogen sorption properties at cryogenic temperatures. An excellent correlation is found between O-2/N-2 selectivities determined experimentally at 77 K and the difference in O-2 and N-2 binding energies calculated from DFTmore » modeling data: Mn > Fe Co >> Cu. Room temperature gas sorption studies were also performed and correlated with metal substitution. The Fe-exchanged sample shows a significantly higher nitrogen isosteric heat of adsorption at temperatures close to ambient conditions (273-298 K) as compared to all other metals studied, indicative of favorable interactions between N-2 and coordinatively unsaturated Fe metal centers. Interestingly, differences in gas adsorption results at cryogenic and room temperatures are evident; they are explained by comparing experimental results with DFT binding energies (0 K) and room temperature Grand Canonical Monte Carlo simulations.« less

Mechanistic study of manganese-substituted glycerol dehydrogenase using a kinetic and thermodynamic analysis.

PubMed

Fang, Baishan; Niu, Jin; Ren, Hong; Guo, Yingxia; Wang, Shizhen

2014-01-01

Mechanistic insights regarding the activity enhancement of dehydrogenase by metal ion substitution were investigated by a simple method using a kinetic and thermodynamic analysis. By profiling the binding energy of both the substrate and product, the metal ion's role in catalysis enhancement was revealed. Glycerol dehydrogenase (GDH) from Klebsiella pneumoniae sp., which demonstrated an improvement in activity by the substitution of a zinc ion with a manganese ion, was used as a model for the mechanistic study of metal ion substitution. A kinetic model based on an ordered Bi-Bi mechanism was proposed considering the noncompetitive product inhibition of dihydroxyacetone (DHA) and the competitive product inhibition of NADH. By obtaining preliminary kinetic parameters of substrate and product inhibition, the number of estimated parameters was reduced from 10 to 4 for a nonlinear regression-based kinetic parameter estimation. The simulated values of time-concentration curves fit the experimental values well, with an average relative error of 11.5% and 12.7% for Mn-GDH and GDH, respectively. A comparison of the binding energy of enzyme ternary complex for Mn-GDH and GDH derived from kinetic parameters indicated that metal ion substitution accelerated the release of dioxyacetone. The metal ion's role in catalysis enhancement was explicated.

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.

Glucose metabolism in the developing brain.

PubMed

Vannucci, R C; Vannucci, S J

2000-04-01

As in adults, glucose is the predominant cerebral energy fuel for the fetus and newborn. Studies in experimental animals and humans indicate that cerebral glucose utilization initially is low and increases with maturation with increasing regional heterogeneity. The increases in cerebral glucose utilization with advancing age occurs as a consequence of increasing functional activity and cerebral energy demands. The levels of expression of the 2 primary facilitative glucose transporter proteins in brain, GLUT1 (blood-brain barrier and glia) and GLUT3 (neuronal), display a similar maturational pattern. Alternate cerebral energy fuels, specifically the ketone bodies and lactate, can substitute for glucose, especially during hypoglycemia, thereby protecting the immature brain from potential untoward effects of hypoglycemia. Unlike adults, glucose supplementation during hypoxia-ischemia is protective in the immature brain, whereas hypoglycemia is deleterious. Accordingly, glucose plays a critical role in the developing brain, not only as the primary substrate for energy production but also to allow for normal biosynthetic processes to proceed.

Effect of La3+ substitution with Gd3+ on the resistive switching properties of La0.7Sr0.3MnO3 thin films

NASA Astrophysics Data System (ADS)

Lee, Hong-Sub; Park, Chang-Sun; Park, Hyung-Ho

2014-05-01

This study demonstrated that the resistive switching voltage of perovskite manganite material could be controlled by A-site cation substitution in "A" MnO3 perovskite manganite structure. A partial substitution of La3+ in La0.7Sr0.3MnO3 with smaller cation Gd3+ induced A-site vacancy of the largest Sr2+ cation with surface segregation of SrOy due to ionic size mismatch, and the induced vacancies reduced migration energy barrier. The operating voltage decreased from 3.5 V to 2.5 V due to a favorable condition for electrochemical migration and redox of oxygen ions. Moreover, surface-segregated SrOy was enhanced with Gd-substitution and the SrOy reduced Schottky-like barrier height and resistive switching ratio from the potential drop and screening effect. The relationship between A-site vacancy generation resulting in surface segregation of SrOy and resistive switching behavior was also investigated by energy resolved x-ray photoelectron spectroscopy, O 1s near edge x-ray absorption spectroscopy, and current voltage measurement.

Impedance and AC conductivity studies of Sm3+ substituted 0.8Ba0.2(Bi0.5K0.5)TiO3 lead free ceramics

NASA Astrophysics Data System (ADS)

Sastry, C. V. S. S.; Ramesh, M. N. V.; Ramesh, K. V.

2017-07-01

Samarium substituted 0.8Ba0.2(Bi0.5K0.5)TiO3 (here after abbreviated as BTBKT-20) lead free ceramics with composition 0.8Ba0.2(Bi0.5(1-x)Sm0.5xK0.5)TiO3 (where x=0.01,0.03,0.05) lead free ceramics have been prepared by solid state reaction and followed by high energy ball milling process. The present paper focuses the impedance and ac conductivity studies of Sm substituted BTBKT-20 lead free ceramics. Impedance spectroscopic studies revealthat temperature dependent relaxation process. Single depressed semi circle was observed in Cole-Cole plots, indicates non-Debye kind of relaxation process. Maximum grain resistance was observed for x=0.03 Sm substituted BTBKT-20 sample. Frequency and temperature dependent AC conductivity was calculated and it found to obey the universal Jonscher's power law and the values of activation energies suggest that conduction is ionic in nature.

Energy saving and recovery measures in integrated urban water systems

NASA Astrophysics Data System (ADS)

Freni, Gabriele; Sambito, Mariacrocetta

2017-11-01

The present paper describes different energy production, recovery and saving measures which can be applied in an integrated urban water system. Production measures are often based on the installation of photovoltaic systems; the recovery measures are commonly based on hydraulic turbines, exploiting the available pressure potential to produce energy; saving measures are based on substitution of old pumps with higher efficiency ones. The possibility of substituting some of the pipes of the water supply system can be also considered in a recovery scenario in order to reduce leakages and recovery part of the energy needed for water transport and treatment. The reduction of water losses can be obtained through the Active Leakage Control (ALC) strategies resulting in a reduction in energy consumption and in environmental impact. Measures were applied to a real case study to tested it the efficiency, i.e., the integrated urban water system of the Palermo metropolitan area in Sicily (Italy).

Mitigating environmental impacts through the energetic use of wood: Regional displacement factors generated by means of substituting non-wood heating systems.

PubMed

Wolf, Christian; Klein, Daniel; Richter, Klaus; Weber-Blaschke, Gabriele

2016-11-01

Wood biomass, especially when applied for heating, plays an important role for mitigating environmental impacts such as climate change and the transition towards higher shares of renewable energy in today's energy mix. However, the magnitude of mitigation benefits and burdens associated with wood use can vary greatly depending on regional parameters such as the displaced fossil reference or heating mix. Therefore, regionalized displacement factors, considering region-specific production conditions and substituted products are required when assessing the precise contribution of wood biomass towards the mitigation of environmental impacts. We carried out Life Cycle Assessments of wood heating systems for typical Bavarian conditions and substitute energy carriers with a focus on climate change and particulate matter emissions. In order to showcase regional effects, we created weighted displacement factors for the region of Bavaria, based on installed capacities of individual wood heating systems and the harvested tree species distribution. The study reveals that GHG displacements between -57gCO2-eq.∗MJ(-1) of useful energy through the substitution of natural gas with a 15kW spruce pellets heating system and -165gCO2-eq.∗MJ(-1) through the substitution of power utilized for heating with a modern 6kW beech split log heating system can be achieved. It was shown that the GHG mitigation potentials of wood utilization are overestimated through the common use of light fuel oil as the only reference system. We further propose a methodology for the calculation of displacement factors which is adaptable to other regions worldwide. Based on our approach it is possible to generate displacement factors for wood heating systems which enable accurate decision-making for project planning in households, heating plants, communities and also for entire regions. Copyright © 2016 Elsevier B.V. All rights reserved.

Healthier side dishes at restaurants: an analysis of children's perspectives, menu content, and energy impacts.

PubMed

Anzman-Frasca, Stephanie; Dawes, Franciel; Sliwa, Sarah; Dolan, Peter R; Nelson, Miriam E; Washburn, Kyle; Economos, Christina D

2014-07-04

Children consume restaurant-prepared foods at high rates, suggesting that interventions and policies targeting consumption of these foods have the potential to improve diet quality and attenuate excess energy intake. One approach to encouraging healthier dietary intake in restaurants is to offer fruits and vegetables (FV) as side dishes, as opposed to traditional, energy-dense accompaniments like French fries. The aims of the current study were to examine: children's views about healthier side dishes at restaurants; current side dish offerings on children's menus at leading restaurants; and potential energy reductions when substituting FV side dishes in place of French fries. To investigate children's attitudes, a survey was administered to a nationally representative sample of U.S. 8- to 18-year-olds (n = 1178). To examine current side dish offerings, children's menus from leading quick service (QSR; n = 10) and full service restaurant chains (FSR; n = 10) were analyzed. Energy reductions that could result from substituting commonly-offered FV side dishes for French fries were estimated using nutrition information corresponding to the children's menu items. Two-thirds of children reported that they would not feel negatively about receiving FV sides instead of French fries with kids' meals. Liking/taste was the most common reason that children gave to explain their attitudes about FV side dishes. Nearly all restaurants offered at least 1 FV side dish option, but at most restaurants (60% of QSR; 70% of FSR), FV sides were never served by default. Substituting FV side dishes for French fries yielded an average estimated energy reduction of at least 170 calories. Results highlight some healthy trends in the restaurant context, including the majority of children reporting non-negative attitudes about FV side dishes and the consistent availability of FV side dish options at leading QSR and FSR. Yet the minority of restaurants offer these FV sides by default. Promoting creative, appealing FV side dishes can result in healthier, less energy-dense meals for children. Substituting or displacing energy-dense default side dishes with such FV dishes show promise as part of continued, comprehensive efforts to increase the healthfulness of meals consumed by children in restaurant settings.

The air quality and health co-benefits of alternative post-2020 pathways for achieving peak carbon targets in Jiangsu, China

NASA Astrophysics Data System (ADS)

Liu, M.; Bi, J.; Huang, Y.; Kinney, P. L.

2016-12-01

Jiangsu, which has three national low-carbon pilot cities, is set to be a model province in China for achieving peak carbon targets before 2030. However, according to local planning of responding to climate change, carbon emissions are projected to keep going up before 2020 even the strictest measures are implemented. In other words, innovative measures must be in action after 2020. This work aimed at assessing the air quality and health co-benefits of alternative post-2020 measures to help remove barriers of policy implementation through tying it to local incentives for air quality improvement. To achieve the aim, we select 2010 as baseline year and develop Bussiness As Usual (BAU) and Traditional Carbon Reduction (TCR) scenarios before 2020. Under BAU, only existing climate and air pollution control policies are considered; under TCR, potential climate policies in local planning and existing air pollution control policies are considered. After 2020, integrated gasification combined cycle (IGCC) plant with carbon capture and storage (CCS) technology and large-scale substitution of renewable energy seem to be two promising pathways for achieving peak carbon targets. Therefore, two additional scenarios (TCR-IGCC and TCR-SRE) are set after 2020. Based on the projections of future energy balances and industrial productions, we estimate the pollutant emissions and simulate PM2.5 and ozone concentrations by 2017, 2020, 2030 and 2050 using CMAQ. Then using health impact assessment approach, the premature deaths are estimated and monetized. Results show that the carbon peak in Jiangsu will be achieved before 2030 only under TCR-IGCC and TCR-SRE scenarios. Under three policy scenarios, Jiangsu's carbon emission control targets would have substantial effects on primary air pollutant emissions far beyond those we estimate would be needed to meet the PM2.5 concentration targets in 2017. Compared with IGCC with CCS, large-scale substitutions of renewable energy bring comparable pollutant emission reductions but more health benefits because it reduces more emissions from traffic sources which are more harmful to health. However, large-scale substitution of renewable energy posed challenges on energy supply capacity, which need to be seriously considered in future policy decision.

Investigation on energy conversion technology using biochemical reaction elements, 2

NASA Astrophysics Data System (ADS)

1994-03-01

For measures taken for resource/energy and environmental issues, a study is made on utilization of microbial biochemical reaction. As a reaction system using chemical energy, cited is production of petroleum substitution substances and food/feed by CO2 fixation using hydrogen energy and hydrogen bacteria. As to photo energy utilization, regarded as promising are CO2 fixation using photo energy and microalgae, and production of hydrogen and useful carbon compound using photosynthetic organisms. As living organism/electric energy interconversion, cited is the culture of chemoautotrophic bacteria which fix CO2 using electric energy. For enhancing its conversion efficiency, it is important to develop a technology of gene manipulation of the bacteria and a system to use functional biochemical elements adaptable to the electrode reaction. With regard to utilization of the microorganism metabolic function, the paper presents emission of soluble nitrogen in the hydrosphere into the atmosphere using denitrifying bacteria, removal of phosphorus, reduction in environmental pollution caused by heavy metal dilute solutions, and recovery as resources, etc.

Comparing the Nutritional Impact of Dietary Strategies to Reduce Discretionary Choice Intake in the Australian Adult Population: A Simulation Modelling Study

PubMed Central

Grieger, Jessica A.; Johnson, Brittany J.; Wycherley, Thomas P.; Golley, Rebecca K.

2017-01-01

Dietary strategies to reduce discretionary choice intake are commonly utilized in practice, but evidence on their relative efficacy is lacking. The aim was to compare the potential impact on nutritional intake of three strategies to reducing discretionary choices intake in the Australian adult (19–90 years) population. Dietary simulation modelling using data from the National Nutrition and Physical Activity Survey 2011–2012 was conducted (n = 9341; one 24 h dietary recall). Strategies modelled were: moderation (reduce discretionary choices by 50%, with 0%, 25% or 75% energy compensation); substitution (replace 50% of discretionary choices with core choices); reformulation (replace 50% SFA with unsaturated fats, reduce added sugars by 25%, and reduce sodium by 20%). Compared to the base case (observed) intake, modelled intakes in the moderation scenario showed: −17.3% lower energy (sensitivity analyses, 25% energy compensation −14.2%; 75% energy compensation −8.0%), −20.9% lower SFA (−17.4%; −10.5%), −43.3% lower added sugars (−41.1%; −36.7%) and 17.7% lower sodium (−14.3%; −7.5%). Substitution with a range of core items, or with fruits, vegetables and core beverages only, resulted in similar changes in energy intake (−13.5% and −15.4%), SFA (−17.7% and −20.1%), added sugars (−42.6% and −43%) and sodium (−13.7% and −16.5%), respectively. Reformulating discretionary choices had minimal impact on reducing energy intake but reduced SFA (−10.3% to −30.9%), added sugars (−9.3% to −52.9%), and alcohol (−25.0% to −49.9%) and sodium (−3.3% to −13.2%). The substitution and reformulation scenarios minimized negative changes in fiber, protein and micronutrient intakes. While each strategy has strengths and limitations, substitution of discretionary choices with core foods and beverages may optimize the nutritional impact. PMID:28467387

Fostering Innovation in the Manufacturing Sector through R&D Consortia

NASA Astrophysics Data System (ADS)

McKittrick, M.

2017-12-01

In the U.S. Department of Energy, the Advanced Manufacturing Office (AMO) has the mission to catalyze research, development and adoption of energy-related advanced manufacturing technologies and practices to drive U.S. economic competitiveness and energy productivity. Within strategic areas of manufacturing, AMO brings together manufacturers, suppliers, institutes of higher education, national laboratories, and state and local governments in public-private R&D consortia to accelerate technology innovation. One such R&D Consortia is the Critical Materials Institute (CMI), established in 2013 and led by Ames Laboratory. CMI is a sustained, multidisciplinary effort to develop solutions across the materials lifecycle of materials essential to clean energy technologies and manufacturing, as well as reduce the impact of supply chain disruptions associated with these valuable resources. By bringing together scientists and engineers from diverse disciplines, CMI is addressing challenges in critical materials, including mineral processing, manufacture, substitution, efficient use, and end-of-life recycling; integrating scientific research, engineering innovation, manufacturing and process improvements; and developing a holistic solution to the materials challenges facing the nation. It includes expertise from four national laboratories, seven universities, and ten industry partners to minimize materials criticality as an impediment to the commercialization of clean energy technologies.

Synthesis and first-principle calculations of the structural and electronic properties of Ge-substituted type-VIII Ba8Ga16Sn30 clathrate

NASA Astrophysics Data System (ADS)

Shen, Lanxian; Li, Decong; Liu, Hongxia; Liu, Zuming; Deng, Shukang

2016-12-01

In this study, the structural and electronic structural properties of Ba8Ga16Sn30-xGex (0≤x≤30) are determined by the first-principle method on the basis of density functional theory. Consistent with experimental findings, calculated results reveal that Ge atoms preferentially occupy the 2a and 24g sites in these compounds. As the content of Ge in Ge-substituted clathrate is increased, the lattice parameter is decreased, and the structural stability is enhanced. The bandgaps of the compound at 1≤x≤10 are smaller than those of Ba8Ga16Sn30. By contrast, the bandgaps of the compound at x>10 are larger than those of Ba8Ga16Sn30. The substitution of Ge for Sn affects p-type conductivity but not n-type conductivity. As Ge content increases, the whole conduction band moves to the direction of high energy, and the density of states of valence-band top decreases. The calculated potential energy versus displacement of Ba indicates that the vibration energy of this atom increases as cage size decreases. Because Ge substitution also affects clathrate structural symmetry, the distance of Ba atom deviation from the center of the cage initially increases and subsequently decreases as the Ge content increases.

Nucleophilic Substitution in Solution: Activation Strain Analysis of Weak and Strong Solvent Effects

PubMed Central

Hamlin, Trevor A.; van Beek, Bas; Wolters, Lando P.

2018-01-01

Abstract We have quantum chemically studied the effect of various polar and apolar solvents on the shape of the potential energy surface (PES) of a diverse collection of archetypal nucleophilic substitution reactions at carbon, silicon, phosphorus, and arsenic by using density functional theory at the OLYP/TZ2P level. In the gas phase, all our model SN2 reactions have single‐well PESs, except for the nucleophilic substitution reaction at carbon (SN2@C), which has a double‐well energy profile. The presence of the solvent can have a significant effect on the shape of the PES and, thus, on the nature of the SN2 process. Solvation energies, charges on the nucleophile or leaving group, and structural features are compared for the various SN2 reactions in a spectrum of solvents. We demonstrate how solvation can change the shape of the PES, depending not only on the polarity of the solvent, but also on how the charge is distributed over the interacting molecular moieties during different stages of the reaction. In the case of a nucleophilic substitution at three‐coordinate phosphorus, the reaction can be made to proceed through a single‐well [no transition state (TS)], bimodal barrier (two TSs), and then through a unimodal transition state (one TS) simply by increasing the polarity of the solvent. PMID:29457865

Electronic structure and magnetism of titanium substituted Cd3P2: An ab-initio study

NASA Astrophysics Data System (ADS)

Jaiganesh, G.; Jaya, S. Mathi

2018-05-01

Using the ab-initio computations that are based on the density functional theory, we have investigated the magnetism and electronic properties of one and two Ti atom substituted Cd3P2 compound. The magnetic stability of the substituted compounds was obtained by analyzing the minimum total energies in nonmagnetic, ferromagnetic and antiferromagnetic phases. Our results indicated the formation of magnetic order in one and two Ti atom substituted Cd3P2 as well as metallic characteristics in these systems. A significant value of the magnetic moment of Ti atom is observed from our calculations. We further find that the neighboring Cd and P atoms too acquire a small magnetic moment.

B2O3/SiO2 substitution effect on structure and properties of Na2O-CaO-SrO-P2O5-SiO2 bioactive glasses from molecular dynamics simulations.

PubMed

Ren, Mengguo; Lu, Xiaonan; Deng, Lu; Kuo, Po-Hsuen; Du, Jincheng

2018-05-23

The effect of B2O3/SiO2 substitution in SrO-containing 55S4.3 bioactive glasses on glass structure and properties, such as ionic diffusion and glass transition temperature, was investigated by combining experiments and molecular dynamics simulations with newly developed potentials. Both short-range (such as bond length and bond angle) and medium-range (such as polyhedral connection and ring size distribution) structures were determined as a function of glass composition. The simulation results were used to explain the experimental results for glass properties such as glass transition temperature and bioactivity. The fraction of bridging oxygen increased linearly with increasing B2O3 content, resulting in an increase in overall glass network connectivity. Ion diffusion behavior was found to be sensitive to changes in glass composition and the trend of the change with the level of substitution is also temperature dependent. The differential scanning calorimetry (DSC) results show a decrease in glass transition temperature (Tg) with increasing B2O3 content. This is explained by the increase in ion diffusion coefficient and decrease in ion diffusion energy barrier in glass melts, as suggested by high-temperature range (above Tg) ion diffusion calculations as B2O3/SiO2 substitution increases. In the low-temperature range (below Tg), the Ea for modifier ions increased with B2O3/SiO2 substitution, which can be explained by the increase in glass network connectivity. Vibrational density of states (VDOS) were calculated and show spectral feature changes as a result of the substitution. The change in bioactivity with B2O3/SiO2 substitution is discussed with the change in pH value and release of boric acid into the solution.

75 FR 21289 - Combined Notice of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-23

...: 5 p.m. Eastern Time on Friday, April 30, 2010. Docket Numbers: ER10-468-002. Applicants: Google Energy LLC. Description: Google Energy LLC submits substitute FERC Electric Tariff, Volume No. 1. Filed...

No-carrier-added (NCA) aryl ([sup 18]F) fluorides via the nucleophilic aromatic substitution of electron rich aromatic rings

DOEpatents

Yushin Ding; Fowler, J.S.; Wolf, A.P.

1993-10-19

A method for synthesizing no-carrier-added (NCA) aryl [.sup.18 F] fluoride substituted aromatic aldehyde compositions bearing an electron donating group is described. The method of the present invention includes the step of reacting aromatic nitro aldehydes having a suitably protected hydroxyl substitutent on an electron rich ring. The reaction is The U.S. Government has rights in this invention pursuant to Contract Number DE-AC02-76CH00016, between the U.S. Department of Energy and Associated Universities Inc.

High-energy lithium-ion battery using substituted LiCoPO4: From coin type to 1 Ah cell

NASA Astrophysics Data System (ADS)

Liu, D.; Zhu, W.; Kim, C.; Cho, M.; Guerfi, A.; Delp, S. A.; Allen, J. L.; Jow, T. R.; Zaghib, K.

2018-06-01

Cr, Fe and Si were added to improve the performance of olivine LiCoPO4 in cathodes for lithium-ion batteries. A substituted-LiCoPO4 in a half cell delivered a reversible capacity of 125 mAh/g at C/3 rate, with no capacity loss after over 100 cycles at 25 °C. The well-known capacity fade of LiCoPO4-based cathodes was almost completely eliminated by substituting Cr, Fe and Si.

No-carrier-added (NCA) aryl (18E) fluorides via the nucleophilic aromatic substitution of electron rich aromatic rings

DOEpatents

Ding, Yu-Shin; Fowler, Joanna S.; Wolf, Alfred P.

1993-01-01

A method for synthesizing no-carrier-added (NCA) aryl [.sup.18 F] fluoride substituted aromatic aldehyde compositions bearing an electron donating group is described. The method of the present invention includes the step of reacting aromatic nitro aldehydes having a suitably protected hydroxyl substitutent on an electron rich ring. The reaction is The U.S. Government has rights in this invention pursuant to Contract Number DE-AC02-76CH00016, between the U.S. Department of Energy and Associated Universities Inc.

Energy and other non-renewable resources

NASA Technical Reports Server (NTRS)

1975-01-01

Anticipated U.S. demands for non-renewable energy and mineral resources exceed domestic supplies essential for economic growth. For the long term changes necessary in the energy supply and demand gap, new technologies and substitute materials as well as legislation and socio-economic strategies are elaborated.

Beyond Solar Fuels: Renewable Energy-Driven Chemistry.

PubMed

Lanzafame, Paola; Abate, Salvatare; Ampelli, Claudio; Genovese, Chiara; Passalacqua, Rosalba; Centi, Gabriele; Perathoner, Siglinda

2017-11-23

The future feasibility of decarbonized industrial chemical production based on the substitution of fossil feedstocks (FFs) with renewable energy (RE) sources is discussed. Indeed, the use of FFs as an energy source has the greatest impact on the greenhouse gas emissions of chemical production. This future scenario is indicated as "solar-driven" or "RE-driven" chemistry. Its possible implementation requires to go beyond the concept of solar fuels, in particular to address two key aspects: i) the use of RE-driven processes for the production of base raw materials, such as olefins, methanol, and ammonia, and ii) the development of novel RE-driven routes that simultaneously realize process and energy intensification, particularly in the direction of a significant reduction of the number of the process steps. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

[The social portrait of substitute families and modes of development of medical pedagogical monitoring].

PubMed

Aver'ianova, N I; Khanova, N A

2014-01-01

The study demonstrated that in Russia the major cause of orphanage is a social life-style of biological parents of orphan children. The substitute families are more often large with number of children from 3 to 8 and quarter of them are incomplete. The mean age of substitute parent consists 47.8 ± 1.4 years. The leading motivation to take orphan child/or education in family is the availability of kindred relationship regarding child or "deserted nest syndrome". At the initial phase of establishing of substitute family the most of substitute parents/tutors face with problems of health status and behavioral deviations of foster children. The substitute parents are unsatisfied with quality of medical monitoring of foster children. They also suffer fromdeficiency of information concerning characteristics of development, health conditions and modes of rehabilitation of children. In the judgment of substitute parents/tutors placing child into family conditions effects positively on one's development and health, behavior and emotional background. In substitute families, conditions organized for children can be named as approximated to conditions of residing in biological (home) families. The system of medical psychological and pedagogical monitoring of children of this category is needed in further development.

Energetics of Single Substitutional Impurities in NiTi

NASA Technical Reports Server (NTRS)

Good, Brian S.; Noebe, Ronald

2003-01-01

Shape-memory alloys are of considerable current interest, with applications ranging from stents to Mars rover components. In this work, we present results on the energetics of single substitutional impurities in B2 NiTi. Specifically, energies of Pd, Pt, Zr and Hf impurities at both Ni and Ti sites are computed. All energies are computed using the CASTEP ab initio code, and, for comparison, using the quantum approximate energy method of Bozzolo, Ferrante and Smith. Atomistic relaxation in the vicinity of the impurities is investigated via quantum approximate Monte Carlo simulation, and in cases where the relaxation is found to be important, the resulting relaxations are applied to the ab initio calculations. We compare our results with available experimental work.

Stacking fault effects in Mg-doped GaN

NASA Astrophysics Data System (ADS)

Schmidt, T. M.; Miwa, R. H.; Orellana, W.; Chacham, H.

2002-01-01

First-principles total energy calculations are performed to investigate the interaction of a stacking fault with a p-type impurity in both zinc-blende and wurtzite GaN. For both structures we find that, in the presence of a stacking fault, the impurity level is a more localized state in the band gap. In zinc-blende GaN, the minimum energy position of the substitutional Mg atom is at the plane of the stacking fault. In contrast, in wurtzite GaN the substitutional Mg atom at the plane of the stacking fault is a local minimum and the global minimum is the substitutional Mg far from the fault. This behavior can be understood as a packing effect which induces a distinct strain relief process, since the local structure of the stacking fault in zinc-blende GaN is similar to fault-free wurtzite GaN and vice-versa.

Molecular dynamics simulations of substitutional diffusion

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

Zhou, Xiaowang; Jones, Reese E.; Gruber, Jacob

2016-12-18

In atomistic simulations, diffusion energy barriers are usually calculated for each atomic jump path using a nudged elastic band method. Practical materials often involve thousands of distinct atomic jump paths that are not known a priori. Hence, it is often preferred to determine an overall diffusion energy barrier and an overall pre-exponential factor from the Arrhenius equation constructed through molecular dynamics simulations of mean square displacement of the diffusion species at different temperatures. This approach has been well established for interstitial diffusion, but not for substitutional diffusion at the same confidence. Using In 0.1 Ga 0.9 N as an example,more » we have identified conditions where molecular dynamics simulations can be used to calculate highly converged Arrhenius plots for substitutional alloys. As a result, this may enable many complex diffusion problems to be easily and reliably studied in the future using molecular dynamics, provided that moderate computing resources are available.« less

Prospects for coal briquettes as a substitute fuel for wood and charcoal in US Agency for International Development Assisted countries

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

Perlack, R.D.; Stevenson, G.G.; Shelton, R.B.

1986-02-01

Fuelwood shortages and potential shortages are widespread throughout the developing world, and are becoming increasingly more prevalent because of the clearing of land for subsistence and plantation agriculture, excessive and inefficient commercial timber harvesting for domestic and export construction, and charcoal production to meet rising urban demands. Further, the environmental and socioeconomic consequences of the resulting deforestation are both pervasive and complex. This report focuses on the substitution of coal briquettes for fuelwood. Although substantial adverse health effects could be expected from burning non-anthracite coal or coal briquettes, a well-developed technique, carbonization, exists to convert coal to a safer formmore » for combustion. The costs associated with briquetting and carbonizing coal indicate that ''smokeless'' coal briquettes can be produced at costs competitive with fuelwood and charcoal. The US Agency for International Development (USAID) is working on implementing this energy option in Haiti and Pakistan by (1) evaluating resources, (2) assessing markets, (3) analyzing technologies, (4) studying government policy and planning, and (5) packaging the idea for the private sector to implement. 26 refs., 2 figs., 12 tabs.« less

"CH"/N substituted mer-Gaq3 and mer-Alq3 derivatives: an effective approach for the tuning of emitting color.

PubMed

Gahungu, Godefroid; Zhang, Jingping

2005-09-22

Equilibrium geometry configurations of the "CH"/N substituted Alq3 and Gaq3 derivatives are calculated by density functional theory (B3LYP/6-31G). The frontier molecular orbital and gap energy calculations for all complexes have been performed at the HF/6-31G level. It was shown that, compared to the pristine molecules, the HOMO and LUMO are stabilized, the net effect being however an increasing/decreasing of the gap (Eg) depending on the position of the substituted group. On the basis of the equilibrium geometries, the effect of the substitution on the absorption and emission spectra was evaluated using TDB3LYP/3-21G. It was shown that the change of "CH"/N substituted position on 8-hydroxyquinoline ligand is a powerful approach for the tuning of emitting color. An important blue shift was predicted for 5-substituted 8-hydroxyquinoline derivatives, an important red one being observed for 4-substituted ones. Interestingly, relatively significant blue and red shifts were also predicted for the 7- and 2-substituted derivatives. In this work, the correlation between the spectrum shifts and the metal-ligand bonding is also discussed.

Impacts of Vehicle Weight Reduction via Material Substitution on Life-Cycle Greenhouse Gas Emissions.

PubMed

Kelly, Jarod C; Sullivan, John L; Burnham, Andrew; Elgowainy, Amgad

2015-10-20

This study examines the vehicle-cycle and vehicle total life-cycle impacts of substituting lightweight materials into vehicles. We determine part-based greenhouse gas (GHG) emission ratios by collecting material substitution data and evaluating that alongside known mass-based GHG ratios (using and updating Argonne National Laboratory's GREET model) associated with material pair substitutions. Several vehicle parts are lightweighted via material substitution, using substitution ratios from a U.S. Department of Energy report, to determine GHG emissions. We then examine fuel-cycle GHG reductions from lightweighting. The fuel reduction value methodology is applied using FRV estimates of 0.15-0.25, and 0.25-0.5 L/(100km·100 kg), with and without powertrain adjustments, respectively. GHG breakeven values are derived for both driving distance and material substitution ratio. While material substitution can reduce vehicle weight, it often increases vehicle-cycle GHGs. It is likely that replacing steel (the dominant vehicle material) with wrought aluminum, carbon fiber reinforced plastic (CRFP), or magnesium will increase vehicle-cycle GHGs. However, lifetime fuel economy benefits often outweigh the vehicle-cycle, resulting in a net total life-cycle GHG benefit. This is the case for steel replaced by wrought aluminum in all assumed cases, and for CFRP and magnesium except for high substitution ratio and low FRV.

Partial Derivatives, the Energy Crisis, and Urban Transportation: Calculus for Concerned Citizens

ERIC Educational Resources Information Center

Bent, Henry A.

1976-01-01

Presented is a method utilizing partial derivatives for determining the energy saved per dollar by substituting bicycling for driving a car while not reducing jobs dependent upon the auto industry. (SL)

7 CFR 4280.144 - Transfer of lenders.

Code of Federal Regulations, 2014 CFR

2014-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Rural Energy for America Program General Renewable Energy System and Energy Efficiency Improvement Guaranteed Loans § 4280.144 Transfer of... will be the Agency rather than the loan approval official who may approve the substitution of a new...

7 CFR 4280.144 - Transfer of lenders.

Code of Federal Regulations, 2013 CFR

2013-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Rural Energy for America Program General Renewable Energy System and Energy Efficiency Improvement Guaranteed Loans § 4280.144 Transfer of... will be the Agency rather than the loan approval official who may approve the substitution of a new...

7 CFR 4280.144 - Transfer of lenders.

Code of Federal Regulations, 2012 CFR

2012-01-01

... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE LOANS AND GRANTS Rural Energy for America Program General Renewable Energy System and Energy Efficiency Improvement Guaranteed Loans § 4280.144 Transfer of... will be the Agency rather than the loan approval official who may approve the substitution of a new...

Postweaning substitution of grazed forage with a high-energy concentrate has variable long-term effects on subcutaneous fat and marbling in Bos taurus genotypes.

PubMed

Greenwood, P L; Siddell, J P; Walmsley, B J; Geesink, G H; Pethick, D W; McPhee, M J

2015-08-01

The objective of this study was to quantify the effects and interactions of stage of growth and genotype on commercial carcass traits and intramuscular fat (IMF) content in 5 muscles of steers ( = 165) and to test the hypothesis that substituting pasture with a high-energy concentrate during the immediate postweaning period increases IMF. Cattle of 3 genotypes (Angus, Hereford, and Wagyu × Angus; = 55/genotype) were selected at weaning from commercial herds, targeting genotypic differences in marbling and subcutaneous fatness. Following weaning, steers were fed for 168 d within 2 different improved, temperate pasture-based nutritional systems: a forage-only system (FS) and forage with high-energy supplemented system (SS), with 2 replicates per system. The supplement was fed at a level of 1% of average BW adjusted every 2 wk to provide an estimated 50% of energy requirements for 168 d from weaning. Pasture on offer in both systems was managed to match the BW of the FS and SS steers during the postweaning treatment period to avoid confounding due to differences in growth rate during this period. Steers were then regrouped into 2 replicates and backgrounded on improved, temperate pasture for 158 d and then grain fed within 1 group for 105 d (short fed) or 259 d (long fed). Groups were slaughtered at commencement (d 0) and end of postweaning nutritional treatments (d 168), end of backgrounding (d 326), and after short (d 431) or long feedlotting (d 585). Serial slaughter stage had an effect on all traits assessed ( < 0.01). The FS steers had more rib fat ( < 0.01) and higher Meat Standards Australia marbling score ( < 0.05) and a tendency ( < 0.10) to have greater eye muscle area than the SS steers throughout the study. Genotypic differences were evident ( < 0.05) for all traits assessed except HCW, dressing percentage, rib fat depth, ossification score, ultimate pH, and IMF in the semitendinosus muscle. The results for marbling and IMF do not support the use of a high-energy feed as a substitute for an equivalent amount of energy from pasture during the immediate postweaning period to enhance development of marbling.

Site preference and magnetic properties of Ga/In-substituted strontium hexaferrite: An ab initio study

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

Dixit, Vivek; Nandadasa, Chandani N.; Kim, Seong-Gon, E-mail: kimsg@ccs.msstate.edu

2015-11-28

The first-principles density functional theory has been used to study Ga/In-substituted strontium hexaferrite (SrFe{sub 12}O{sub 19}). Based on the calculation of the substitution energy of Ga and In in SrFe{sub 12}O{sub 19} and the formation probability analysis, we conclude that in SrFe{sub 12−x}Ga{sub x}O{sub 19} the substituted Ga atoms prefer to occupy the 12k, 2a, and 4f{sub 1} sites, while In atoms in SrFe{sub 12−x}In{sub x}O{sub 19} occupy the 12k, 4f{sub 2}, and 4f{sub 1} sites. We used the site occupation probabilities to calculate the magnetic properties of the substituted SrFe{sub 12}O{sub 19}. It was found that as the fractionmore » of Ga atoms in SrFe{sub 12−x}Ga{sub x}O{sub 19} increases, the saturation magnetization (M{sub s}) as well as magnetic anisotropy energy (MAE) decrease, while the anisotropy field (H{sub a}) increases. In the case of SrFe{sub 12−x}In{sub x}O{sub 19}, M{sub s}, MAE, and H{sub a} decrease with an increase of the concentration of In atoms.« less

Membrane separation systems---A research and development needs assessment

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

Baker, R.W.; Cussler, E.L.; Eykamp, W.

1990-03-01

Membrane based separation technology, a relative newcomer on the separations scene, has demonstrated the potential of saving enormous amounts of energy in the processing industries if substituted for conventional separation systems. Over 1 quad annually, out of 2.6, can possibly be saved in liquid-to-gas separations, alone, if membrane separation systems gain wider acceptance, according to a recent DOE/OIP (DOE/NBM-80027730 (1986)) study. In recent years great strides have been made in the field and offer even greater energy savings in the future when substituted for other conventional separation techniques such as distillation, evaporation, filtration, sedimentation, and absorption. An assessment was conductedmore » by a group of six internationally known membrane separations experts who examined the worldwide status of research in the seven major membrane areas. This encompassed four mature technology areas: reverse osmosis, micorfiltration, ultrafiltration, and electrodialysis; two developing areas: gas separation and and pervaporation; and one emerging technology: facilitated transport. Particular attention was paid to identifying the innovative processes currently emerging, and even further improvements which could gain wider acceptance for the more mature membrane technology. The topics that were pointed out as having the greatest research emphasis are pervaporation for organic-organic separations; gas separation; micorfiltration; an oxidant-resistant reverse osmosis membrane; and a fouling-resistant ultrafiltration membrane. 35 refs., 6 figs., 22 tabs.« less

Peptide selectivity between the PDZ domains of human pregnancy-related serine proteases (HtrA1, HtrA2, HtrA3, and HtrA4) can be reshaped by different halogen probes.

PubMed

Sun, Mei-Ling; Sun, Li-Mei; Wang, Yong-Qing

2018-06-01

The human HtrA family of serine proteases (HtrA1, HtrA2, HtrA3, and HtrA4) are the key enzymes associated with pregnancy and closely related to the development and progression of many pathological events. Previously, it was found that halogen substitution at the indole moiety of peptide Trp-1 residue can form a geometrically satisfactory halogen bond with the Drosophila discs large, zona occludens-1 (PDZ) domain of HtrA proteases. Here, we attempt to systematically investigate the effect of substitution with 4 halogen types and 2 indole positions on the binding affinity and specificity of peptide ligands to the 4 HtrA PDZ domains. The complex structures, interaction energies, halogen-bonding strength, and binding affinity of domain-peptide systems were modeled, analyzed, and measured via computational modeling and fluorescence-based assay. It is revealed that there is a compromise between the local rearrangement of halogen bond involving different halogen atoms and the global optimization of domain-peptide interaction; the substitution position is fundamentally important for peptide-binding affinity, while the halogen type can effectively shift peptide selectivity between the 4 domains. The HtrA1-PDZ and HtrA4-PDZ as well as HtrA2-PDZ and HtrA3-PDZ respond similarly to different halogen substitutions of peptide; -Br substitution at R2-position and -I substitution at R4-position are most effective in improving peptide selectivity for HtrA1-PDZ/HtrA4-PDZ and HtrA2-PDZ/HtrA3-PDZ, respectively; -F substitution would not address substantial effect on peptide selectivity for all the 4 domains. Consequently, the binding affinities of a native peptide ligand DSRIWWV -COOH as well as its 4 R2-halogenated counterparts were determined as 1.9, 1.4, 0.5, 0.27, and 0.92 μM, which are basically consistent with computational analysis. This study would help to rationally design selective peptide inhibitors of HtrA family members by using different halogen substitutions. Copyright © 2017 John Wiley & Sons, Ltd.

Trends in the development of industrially assimilated renewable energy: the problem of resource restrictions

NASA Astrophysics Data System (ADS)

Nizhegorodtsev, R. M.; Ratner, S. V.

2016-03-01

An analysis of the dynamics of the development of wind and solar energy and potential resource restrictions of the dissemination of these technologies of energy generation associated with intensive use of rare earth metals and some other mineral resources are presented. The technological prospects of various directions of decisions of the problem of resource restrictions, including escalating of volumes of extraction and production of necessary mineral components, creating substitutes of scarce materials and development of recycling are considered. The bottlenecks of each of the above-mentioned decisions were founded. Conclusions are drawn on the prospects of development of the Russian high-tech sectors of the economy in the context of the most probable decisions of the problem of resource restrictions of wind and solar energy. An increase in extraction and production of rare earth metals and some other materials, stimulation of domestic research and development (R&D) to create the permanent magnets of new types and new technologies of wind-powered generation, and reduction of the resource-demand and technology development of recycling the components of power equipment are the most prospective directions of progress. The innovations in these directions will be in demand on the European, Chinese, and North American markets in the near decades due to the end of the life cycle (approximately 30 years) of wind and solar energy projects started at the turn of the 20th-21st centuries (the beginning of exponential growth in plants). The private investors and relevant regional and federal government agencies can use the qualitative characteristics of the dynamics of industrially assimilated renewable energy to choose the most promising investment orientations in energy projects and selection of the most economically sound development methods of energy and related industries.

Possible reason for the unusual regioselectivity in nucleophilic ring opening of trisubstituted aziridines under mildly basic conditions.

PubMed

Kelley, Brandon T; Carroll, Patrick; Joullié, Madeleine M

2014-06-06

2,2,3-Trisubstituted aziridines are known to undergo ring opening at the more substituted carbon under mildly basic conditions. However, the reason for the formation of the more sterically encumbered product has never been examined. Several trisubstituted aziridines, with different substitution patterns at the C-2 and C-3 carbons, were synthesized to change the electronics of the aziridine ring system. These changes had no effect on the regioselectivity of the ring-opening reaction. Using the B3LYP/6-31G* DFT basis set it was determined that the transition state for opening at the more substituted carbon proceeds at a lower energy than the transition state at the less substituted carbon.

Physical properties of FePt nanocomposite doped with Ag atoms: First-principles study

NASA Astrophysics Data System (ADS)

Jia, Yong-Fei; Shu, Xiao-Lin; Xie, Yong; Chen, Zi-Yu

2014-07-01

L10 FePt nanocomposite with high magnetocrystalline anisotropy energy has been extensively investigated in the fields of ultra-high density magnetic recording media. However, the order—disorder transition temperature of the nanocomposite is higher than 600 °C, which is a disadvantage for the use of the material due to the sustained growth of FePt grain under the temperature. To address the problem, addition of Ag atoms has been proposed, but the magnetic properties of the doped system are still unclear so far. Here in this paper, we use first-principles method to study the lattice parameters, formation energy, electronic structure, atomic magnetic moment and order—disorder transition temperature of L10 FePt with Ag atom doping. The results show that the formation energy of a Ag atom substituting for a Pt site is 1.309 eV, which is lower than that of substituting for an Fe site 1.346 eV. The formation energy of substituting for the two nearest Pt sites is 2.560 eV lower than that of substituting for the further sites 2.621 eV, which indicates that Ag dopants tend to segregate L10 FePt. The special quasirandom structures (SQSs) for the pure FePt and the FePt doped with two Ag atoms at the stable Pt sites show that the order—disorder transition temperatures are 1377 °C and 600 °C, respectively, suggesting that the transition temperature can be reduced with Ag atom, and therefore the FePt grain growth is suppressed. The saturation magnetizations of the pure FePt and the two Ag atoms doped FePt are 1083 emu/cc and 1062 emu/cc, respectively, indicating that the magnetic property of the doped system is almost unchanged.

Adhesion of protein residues to substituted (111) diamond surfaces: an insight from density functional theory and classical molecular dynamics simulations.

PubMed

Borisenko, Konstantin B; Reavy, Helen J; Zhao, Qi; Abel, Eric W

2008-09-15

Protein-repellent diamond coatings have great potential value for surface coatings on implants and surgical instruments. The design of these coatings relies on a fundamental understanding of the intermolecular interactions involved in the adhesion of proteins to surfaces. To get insight into these interactions, adhesion energies of glycine to pure and Si and N-doped (111) diamond surfaces represented as clusters were calculated in the gas phase, using density functional theory (DFT) at the B3LYP/6-31G* level. The computed adhesion energies indicated that adhesion of glycine to diamond surface may be modified by introducing additional elements into the surface. The adhesion was also found to induce considerable change in the conformation of glycine when compared with the lowest-energy conformer of the free molecule. In the Si and N-substituted diamond clusters, notable changes in the structures involving the substituents atoms when compared with smaller parent molecules, such as 1-methyl-1-silaadamantane and 1-azaadamantane, were detected. Adhesion free energy differences were estimated for a series of representative peptides (hydrophobic Phe-Gly-Phe, amphiphilic Arg-Gly-Phe, and hydrophilic Arg-Gly-Arg) to a (111) diamond surface substituted with different amounts of N, Si, or F, using molecular dynamics simulations in an explicit water environment employing a Dreiding force field. The calculations were in agreement with the DFT results in that adsorption of the studied peptides to diamond surface is influenced by introducing additional elements to the surface. It has been shown that, in general, substitution will enhance electrostatic interactions between a surface and surrounding water, leading to a weaker adhesion of the studied peptides.

Synthesis, photophysical, and electrochemical properties of wide band gap tetraphenylsilane-carbazole derivatives: Effect of the substitution position and naphthalene side chain

NASA Astrophysics Data System (ADS)

Ho, Kar Wei; Ariffin, A.

2016-12-01

Four tetraphenylsilane-carbazole derivatives with wide bandgaps (3.38-3.55 eV) were synthesized. The effects of the substitution position and of the presence of naphthalene groups on the photophysical, electrochemical and thermal properties were investigated. The derivatives exhibited maximum absorption peaks ranging from 293 to 304 nm and maximum emission peaks ranging from 347 to 386 nm. Changing the carbazole substitution position on the tetraphenylsilane did not significantly change the photophysical and electrochemical properties. However, p-substituted compounds exhibited higher glass transition temperatures than m-substituted compounds. Naphthalene groups with bulky structures had extended the conjugation lengths that red-shifted both the absorption and emission spectra. The LUMO level was decreased, which reduced the optical bandgap and triplet energy level. However, the naphthalene groups significantly improved the thermal stability by increasing the glass transition temperature of the compounds.

Generalized Majority Logic Criterion to Analyze the Statistical Strength of S-Boxes

NASA Astrophysics Data System (ADS)

Hussain, Iqtadar; Shah, Tariq; Gondal, Muhammad Asif; Mahmood, Hasan

2012-05-01

The majority logic criterion is applicable in the evaluation process of substitution boxes used in the advanced encryption standard (AES). The performance of modified or advanced substitution boxes is predicted by processing the results of statistical analysis by the majority logic criteria. In this paper, we use the majority logic criteria to analyze some popular and prevailing substitution boxes used in encryption processes. In particular, the majority logic criterion is applied to AES, affine power affine (APA), Gray, Lui J, residue prime, S8 AES, Skipjack, and Xyi substitution boxes. The majority logic criterion is further extended into a generalized majority logic criterion which has a broader spectrum of analyzing the effectiveness of substitution boxes in image encryption applications. The integral components of the statistical analyses used for the generalized majority logic criterion are derived from results of entropy analysis, contrast analysis, correlation analysis, homogeneity analysis, energy analysis, and mean of absolute deviation (MAD) analysis.

The role of forests in energy and climate change - integrating objectives

Treesearch

Dave Atkins

2010-01-01

Woody biomass utilization presents a tremendous opportunity to address energy independence directly through the use of domestic wood as an energy source that offsets fossil fuel. It also works indirectly through conservation by the substitution of wood for higher embodied energy construction materials such as concrete and steel. Both the direct and indirect measures...

Calculating pKa values for substituted phenols and hydration energies for other compounds with the first-order Fuzzy-Border continuum solvation model

PubMed Central

Sharma, Ity; Kaminski, George A.

2012-01-01

We have computed pKa values for eleven substituted phenol compounds using the continuum Fuzzy-Border (FB) solvation model. Hydration energies for 40 other compounds, including alkanes, alkenes, alkynes, ketones, amines, alcohols, ethers, aromatics, amides, heterocycles, thiols, sulfides and acids have been calculated. The overall average unsigned error in the calculated acidity constant values was equal to 0.41 pH units and the average error in the solvation energies was 0.076 kcal/mol. We have also reproduced pKa values of propanoic and butanoic acids within ca. 0.1 pH units from the experimental values by fitting the solvation parameters for carboxylate ion carbon and oxygen atoms. The FB model combines two distinguishing features. First, it limits the amount of noise which is common in numerical treatment of continuum solvation models by using fixed-position grid points. Second, it employs either second- or first-order approximation for the solvent polarization, depending on a particular implementation. These approximations are similar to those used for solute and explicit solvent fast polarization treatment which we developed previously. This article describes results of employing the first-order technique. This approximation places the presented methodology between the Generalized Born and Poisson-Boltzmann continuum solvation models with respect to their accuracy of reproducing the many-body effects in modeling a continuum solvent. PMID:22815192

Spent nuclear fuel assembly inspection using neutron computed tomography

NASA Astrophysics Data System (ADS)

Pope, Chad Lee

The research presented here focuses on spent nuclear fuel assembly inspection using neutron computed tomography. Experimental measurements involving neutron beam transmission through a spent nuclear fuel assembly serve as benchmark measurements for an MCNP simulation model. Comparison of measured results to simulation results shows good agreement. Generation of tomography images from MCNP tally results was accomplished using adapted versions of built in MATLAB algorithms. Multiple fuel assembly models were examined to provide a broad set of conclusions. Tomography images revealing assembly geometric information including the fuel element lattice structure and missing elements can be obtained using high energy neutrons. A projection difference technique was developed which reveals the substitution of unirradiated fuel elements for irradiated fuel elements, using high energy neutrons. More subtle material differences such as altering the burnup of individual elements can be identified with lower energy neutrons provided the scattered neutron contribution to the image is limited. The research results show that neutron computed tomography can be used to inspect spent nuclear fuel assemblies for the purpose of identifying anomalies such as missing elements or substituted elements. The ability to identify anomalies in spent fuel assemblies can be used to deter diversion of material by increasing the risk of early detection as well as improve reprocessing facility operations by confirming the spent fuel configuration is as expected or allowing segregation if anomalies are detected.

Calculations of binding affinity between C8-substituted GTP analogs and the bacterial cell-division protein FtsZ

PubMed Central

Hritz, Jozef; Läppchen, Tilman

2010-01-01

The FtsZ protein is a self-polymerizing GTPase that plays a central role in bacterial cell division. Several C8-substituted GTP analogs are known to inhibit the polymerization of FtsZ by competing for the same binding site as its endogenous activating ligand GTP. Free energy calculations of the relative binding affinities to FtsZ for a set of five C8-substituted GTP analogs were performed. The calculated values agree well with the available experimental data, and the main contribution to the free energy differences is determined to be the conformational restriction of the ligands. The dihedral angle distributions around the glycosidic bond of these compounds in water are known to vary considerably depending on the physicochemical properties of the substituent at C8. However, within the FtsZ protein, this substitution has a negligible influence on the dihedral angle distributions, which fall within the narrow range of −140° to −90° for all investigated compounds. The corresponding ensemble average of the coupling constants 3J(C4,H1′) is calculated to be 2.95 ± 0.1 Hz. The contribution of the conformational selection of the GTP analogs upon binding was quantified from the corresponding populations. The obtained restraining free energy values follow the same trend as the relative binding affinities to FtsZ, indicating their dominant contribution. PMID:20559630

Improving energy sustainability for public buildings in Italian mountain communities.

PubMed

Mutani, Guglielmina; Cornaglia, Mauro; Berto, Massimo

2018-05-01

The objective of this work is to analyze and then optimize thermal energy consumptions of public buildings located within the mountain community of Lanzo, Ceronda and Casternone Valleys. Some measures have been proposed to reduce energy consumption and consequently the economic cost for energy production, as well as the harmful GHG emissions in the atmosphere. Initially, a study of the mountain territory has been carried out, because of its vast extension and climatic differences. Defined the communities and the buildings under investigation, energy dependant data were collected for the analysis of energy consumption monitoring: consumption data of three heating seasons, geometric buildings characteristics, type of opaque and transparent envelope, heating systems information with boiler performance and climatic data. Afterward, five buildings with critical energy performances were selected; for each of these buildings, different retrofit interventions have been hypothesized to reduce the energy consumption, with thermal insulation of vertical or horizontal structures, new windows or boiler substitution. The cost-optimal technique was used to choose the interventions that offered higher energy performance at lower costs; then a retrofit scenario has been planned with a specific financial investment. Finally, results showed possible future developments and scenarios related to buildings energy efficiency with regard to the topic of biomass exploitation and its local availability in this area. In this context, the biomass energy resource could to create a virtuous environmental, economic and social process, favouring also local development.

Energy Level Tuning of Poly(phenylene-alt-dithienobenzothiadiazole)s for Low Photon Energy Loss Solar Cells.

PubMed

Heuvel, Ruurd; van Franeker, Jacobus J; Janssen, René A J

2017-03-01

Six poly(phenylene- alt -dithienobenzothiadiazole)-based polymers have been synthesized for application in polymer-fullerene solar cells. Hydrogen, fluorine, or nitrile substitution on benzo-thiadiazole and alkoxy or ester substitution on the phenylene moiety are investigated to reduce the energy loss per converted photon. Power conversion efficiencies (PCEs) up to 6.6% have been obtained. The best performance is found for the polymer-fullerene combination with distinct phase separation and crystalline domains. This improves the maximum external quantum efficiency for charge formation and collection to 66%. The resulting higher photocurrent compensates for the relatively large energy loss per photon ( E loss = 0.97 eV) in achieving a high PCE. By contrast, the poly-mer that provides a reduced energy loss ( E loss = 0.49 eV) gives a lower photocurrent and a reduced PCE of 1.8% because the external quantum efficiency of 17% is limited by a suboptimal morphology and a reduced driving force for charge transfer.

Oral mucosa: an alternative epidermic cell source to develop autologous dermal-epidermal substitutes from diabetic subjects.

PubMed

Guzmán-Uribe, Daniela; Alvarado-Estrada, Keila Neri; Pierdant-Pérez, Mauricio; Torres-Álvarez, Bertha; Sánchez-Aguilar, Jesus Martin; Rosales-Ibáñez, Raúl

2017-01-01

The aim of this study was to obtain autologous dermal-epidermal skin substitutes from oral mucosa from diabetic subjects as a first step towards a possible clinical application for cases of diabetic foot. Oral mucosa was obtained from diabetic and healthy subjects (n=20 per group). Epidermal cells were isolated and cultured using autologous fibrin to develop dermal-epidermal in vitro substitutes by the air-liquid technique with autologous human serum as a supplement media. Substitutes were immunocharacterized with collagen IV and cytokeratin 5-14 as specific markers. A Student´s t- test was performed to assess the differences between both groups. It was possible to isolate epidermal cells from the oral mucosa of diabetic and healthy subjects and develop autologous dermal-epidermal skin substitutes using autologous serum as a supplement. Differences in the expression of specific markers were observed and the cytokeratin 5-14 expression was lower in the diabetic substitutes, and the collagen IV expression was higher in the diabetic substitutes when compared with the healthy group, showing a significant difference. Cells from oral mucosa could be an alternative and less invasive source for skin substitutes and wound healing. A difference in collagen production of diabetic cells suggests diabetic substitutes could improve diabetic wound healing. More research is needed to determine the crosstalk between components of these skin substitutes and damaged tissues.

Diversification of energy sources

NASA Technical Reports Server (NTRS)

1975-01-01

The concept of energy source diversification was introduced as a substitution conservation action. The current status and philosophy behind a diversification program is presented in the context of a national energy policy. Advantages, disadvantages (constraints), and methods of implementation for diversification are discussed. The energy source systems for diversification are listed and an example impact assessment is outlined which deals with the water requirements of the specific energy systems.

Bio-solid-State processes for synthesis of Li-Fe-phosphate.

PubMed

Kim, Hyoung-Bum; Park, Byungno; Lee, Insung; Roh, Yul

2008-10-01

Lithium-Fe-phosphates have become of great interest as storage cathodes for rechargeable Li-batteries because of their high density, environmental friendliness, and safety. The objective of this study was to examine bio-solid-state synthesis of LiFePO4 by microbial processes at room temperature. The microbial reduction of Fe(III)-citrate using an organic carbon, glucose, as an electron donor in the presence of NaHPO4 and lithium that resulted in the formation of Li-substituted iron phosphate. Our studies showed that bacteria enriched from inter-tidal flat sediments, designated as Haejae-1, synthesized Li-substituted iron phosphate. Characterization by X-ray diffraction showed the reduction of Fe(III)-citrate in the presence of NaHPO4 and LiCl2 resulted in the precipitation of Li-substituted vivianite [Li(x)Fe(3-x)(PO4)2 x 8H2O]. SEM-EDX, FTIR, and ESCA analyses showed the chemical composition of the synthesized phases was Li, Fe, P, C, and O. Based on the chemical and physical structure of the mineral, the novel bio-nano-material may be potentially useful to the development of energy storage materials.

Electrostatic effects on the folding stability of FKBP

NASA Astrophysics Data System (ADS)

Batra, Jyotica; Zhou, Huan-Xiang

2006-11-01

Charged residues play important roles in the folding of proteins and their interactions with biological targets. We have developed computational models for predicting electrostatic contributions to protein folding and binding stability. To rigorously test and further refine these models, we carried out experimental studies on the effects of charge mutations on the folding stability of FKBP. Two close homologues of FKBP, FKBP12 and FKBP12.6, differ in 18 of 107 positions, and 8 of which involve substitutions of charged residues. These 8 substitutions were introduced on FKBP12 and their effects on the folding stability were measured. The changes in unfolding free energy varied from -0.34 to 0.65 kcal/mol. A double and a triple mutation were introduced to accumulate the stabilization effect of individual substitutions, resulting an increase in stability of about 0.84 kcal/mol. On the other hand, neutralizing one or both partners of a conserved salt bridge reduced the stability by as much as 0.64 kcal/mol. These results suggest that charged residues can modulate the folding stability significantly. To further exploit stabilization effects of charged residues, experiments are now underway to introduce charge mutations that are modeled after a thermophilic FKBP.

Insight into point defects and impurities in titanium from first principles

NASA Astrophysics Data System (ADS)

Nayak, Sanjeev K.; Hung, Cain J.; Sharma, Vinit; Alpay, S. Pamir; Dongare, Avinash M.; Brindley, William J.; Hebert, Rainer J.

2018-03-01

Titanium alloys find extensive use in the aerospace and biomedical industries due to a unique combination of strength, density, and corrosion resistance. Decades of mostly experimental research has led to a large body of knowledge of the processing-microstructure-properties linkages. But much of the existing understanding of point defects that play a significant role in the mechanical properties of titanium is based on semi-empirical rules. In this work, we present the results of a detailed self-consistent first-principles study that was developed to determine formation energies of intrinsic point defects including vacancies, self-interstitials, and extrinsic point defects, such as, interstitial and substitutional impurities/dopants. We find that most elements, regardless of size, prefer substitutional positions, but highly electronegative elements, such as C, N, O, F, S, and Cl, some of which are common impurities in Ti, occupy interstitial positions.

The Rotational Spectrum of Singly and Doubly 13C-SUBSTITUTED Dimethylether

NASA Astrophysics Data System (ADS)

Koerber, Monika; Endres, Christian P.; Lewen, Frank; Giesen, Thomas F.; Schlemmer, Stephan; Pohl, Roland; Klein, Axel

2010-06-01

Dimethylether (DME) is a nearly prolate asymmetric top with two internal rotors (methyl groups) which undergo periodic large amplitude motions and show a complicated torsional splitting of each rotational energy level. Due to its complex spectrum and its high abundance in hot cores such as Orion KL or Sagittarius B2 at temperatures exceeding 100 K, DME is very prominent in astronomical line surveys and contributes to spectral line confusion of such sources. The interpretation of astronomical observations therefore depends on the knowledge of accurate rest frequencies and reliable intensities. Precise predictions for the ground state of DME's main isotopologue are now available up to 2.1 THz In contrast, very little is known about 13C-substituted DME. Only a few data are available on singly 13C-substituted DME, 12CH_3O13CH_3. However, no data are available on doubly 13C-substituted DME, (13CH_3)_2O, yet. While in (13CH_3)_2O the two internal rotating methyl groups are equivalent and the splitting of rotational energy levels into four substates is comparable to the main isotopologue, singly 13C-substituted DME has two non-equivalent internal rotors resulting in torsional splitting of rotational energy levels into five substates. The purpose of our new laboratory measurements is to extend the knowledge on the astrophysically relevant species 12CH_3O13CH_3. To analyze the complicated spectrum resulting from a 13C-enriched sample of DME, containing all different 13C-substituted species as well as the main isotopologue, also precise data on doubly 13C-substituted DME are inevitable. We performed measurements in the frequency region 35-120 GHz using an all solid state spectrometer. Rotational as well as torsional parameters have been obtained for (13CH_3)_2O as well as 12CH_3O13CH_3 by fitting the assigned transitions to an effective rotational Hamiltonian introduced by Peter Groner. C. Comito et al., Astrophys. J. Suppl. Ser. 156, 127-167 (2005) C. P. Endres et al., Astronomy & Astrophysics 504, 635-640 (2009) Y. Niide and M. Hayashi, J. Mol. Spectrosc. 220, 65-79 (2003) P. Groner, J. Chem. Phys. 107, 4483-4498 (1997).

Environmental assessment of food waste valorization in producing biogas for various types of energy use based on LCA approach.

PubMed

Woon, Kok Sin; Lo, Irene M C; Chiu, Sam L H; Yan, Dickson Y S

2016-04-01

This paper aims to evaluate the environmental impacts of valorizing food waste for three types of energy use, namely electricity and heat, city gas, and biogas fuel as a petrol, diesel, and liquefied petroleum gas substitute for vehicle use, with reference to the Hong Kong scenario. The life cycle based environmental assessment is conducted from bin-to-cradle system boundary via SimaPro 7.2.4 with ReCiPe 1.04. All of the inventory data of included processes is based on reports of government and industrial sectors. The results show that biogas fuel as a petrol substitute for vehicle use is advantageous over other types of energy use in regard to human health and ecosystems, and it is also the best considering the government's future emission reduction targets set out for the power and transport sectors in Hong Kong. By turning 1080 tonnes per day of food waste into biogas vehicle fuel as petrol substitute, it reduces 1.9% of greenhouse gas emissions in the transport sectors, which results a larger decrease of GHG emissions than the achieved mitigation in Hong Kong from 2005 to 2010. Copyright © 2016 Elsevier Ltd. All rights reserved.

Healthier side dishes at restaurants: an analysis of children’s perspectives, menu content, and energy impacts

PubMed Central

2014-01-01

Background Children consume restaurant-prepared foods at high rates, suggesting that interventions and policies targeting consumption of these foods have the potential to improve diet quality and attenuate excess energy intake. One approach to encouraging healthier dietary intake in restaurants is to offer fruits and vegetables (FV) as side dishes, as opposed to traditional, energy-dense accompaniments like French fries. The aims of the current study were to examine: children's views about healthier side dishes at restaurants; current side dish offerings on children's menus at leading restaurants; and potential energy reductions when substituting FV side dishes in place of French fries. Methods To investigate children’s attitudes, a survey was administered to a nationally representative sample of U.S. 8- to 18-year-olds (n = 1178). To examine current side dish offerings, children's menus from leading quick service (QSR; n = 10) and full service restaurant chains (FSR; n = 10) were analyzed. Energy reductions that could result from substituting commonly-offered FV side dishes for French fries were estimated using nutrition information corresponding to the children's menu items. Results Two-thirds of children reported that they would not feel negatively about receiving FV sides instead of French fries with kids' meals. Liking/taste was the most common reason that children gave to explain their attitudes about FV side dishes. Nearly all restaurants offered at least 1 FV side dish option, but at most restaurants (60% of QSR; 70% of FSR), FV sides were never served by default. Substituting FV side dishes for French fries yielded an average estimated energy reduction of at least 170 calories. Conclusions Results highlight some healthy trends in the restaurant context, including the majority of children reporting non-negative attitudes about FV side dishes and the consistent availability of FV side dish options at leading QSR and FSR. Yet the minority of restaurants offer these FV sides by default. Promoting creative, appealing FV side dishes can result in healthier, less energy-dense meals for children. Substituting or displacing energy-dense default side dishes with such FV dishes show promise as part of continued, comprehensive efforts to increase the healthfulness of meals consumed by children in restaurant settings. PMID:24996545

Cadmium Telluride Semiconductor Detector for Improved Spatial and Energy Resolution Radioisotopic Imaging

PubMed Central

Abbaspour, Samira; Mahmoudian, Babak; Islamian, Jalil Pirayesh

2017-01-01

The detector in single-photon emission computed tomography has played a key role in the quality of the images. Over the past few decades, developments in semiconductor detector technology provided an appropriate substitution for scintillation detectors in terms of high sensitivity, better energy resolution, and also high spatial resolution. One of the considered detectors is cadmium telluride (CdTe). The purpose of this paper is to review the CdTe semiconductor detector used in preclinical studies, small organ and small animal imaging, also research in nuclear medicine and other medical imaging modalities by a complete inspect on the material characteristics, irradiation principles, applications, and epitaxial growth method. PMID:28553175

[The substitution effect of leadership substitutes for transformational leadership in nursing organization].

PubMed

Kim, Jeong-Hee

2006-04-01

This paper was conducted to examine the effects of transformational leadership behaviors, within the substitutes for leadership model (Kerr & Jermier, 1978). Data was collected from 181 staff nurses in 3 general hospitals, with self-reporting questionnaires (MLQ developed by Bass, rd-SLS developed by Podsakoff, et al., and MSQ developed by Weiss, et al.). Descriptive statistics, factor analysis, Cronbach's alpha and moderated regression analysis were used. 1) The transformational leader behaviors and substitutes for leadership each had correlations with job satisfaction. 2) The total amount of variance accounted for by the substitutes for leadership was substantially greater than by the transformational leadership behaviors. 3) Few of the substitutes variables moderated the relationships between the transformational leader behaviors and job satisfaction in a manner consistent with that specified by Howell, Dorfman, and Kerr (1986). The finding of this study suggest that leaders need to have a better understanding of those contextual variables that influence job satisfaction. Thus future research should focus attention on the moderating effects of substitutes, as well as the things that leaders can do to influence them. In addition, it may be good to examine the effects of substitutes on other criterion variables.

Enhanced osteoconductivity of sodium-substituted hydroxyapatite by system instability.

PubMed

Sang Cho, Jung; Um, Seung-Hoon; Su Yoo, Dong; Chung, Yong-Chae; Hye Chung, Shin; Lee, Jeong-Cheol; Rhee, Sang-Hoon

2014-07-01

The effect of substituting sodium for calcium on enhanced osteoconductivity of hydroxyapatite was newly investigated. Sodium-substituted hydroxyapatite was synthesized by reacting calcium hydroxide and phosphoric acid with sodium nitrate followed by sintering. As a control, pure hydroxyapatite was prepared under identical conditions, but without the addition of sodium nitrate. Substitution of calcium with sodium in hydroxyapatite produced the structural vacancies for carbonate ion from phosphate site and hydrogen ion from hydroxide site of hydroxyapatite after sintering. The total system energy of sodium-substituted hydroxyapatite with structural defects calculated by ab initio methods based on quantum mechanics was much higher than that of hydroxyapatite, suggesting that the sodium-substituted hydroxyapatite was energetically less stable compared with hydroxyapatite. Indeed, sodium-substituted hydroxyapatite exhibited higher dissolution behavior of constituent elements of hydroxyapatite in simulated body fluid (SBF) and Tris-buffered deionized water compared with hydroxyapatite, which directly affected low-crystalline hydroxyl-carbonate apatite forming capacity by increasing the degree of apatite supersaturation in SBF. Actually, sodium-substituted hydroxyapatite exhibited markedly improved low-crystalline hydroxyl-carbonate apatite forming capacity in SBF and noticeably higher osteoconductivity 4 weeks after implantation in calvarial defects of New Zealand white rabbits compared with hydroxyapatite. In addition, there were no statistically significant differences between hydroxyapatite and sodium-substituted hydroxyapatite on cytotoxicity as determined by BCA assay. Taken together, these results indicate that sodium-substituted hydroxyapatite with structural defects has promising potential for use as a bone grafting material due to its enhanced osteoconductivity compared with hydroxyapatite. © 2013 Wiley Periodicals, Inc.

Impacts of biogas projects on agro-ecosystem in rural areas — A case study of Gongcheng

NASA Astrophysics Data System (ADS)

Yang, Jin; Chen, Weichao; Chen, Bin

2011-09-01

The rapid growth of agro-ecosystem has been the focus of "New Rural Construction" in China due to intensive energy consumption and environmental pollution in rural areas. As a kind of renewable energy, biogas is helpful for new energy development and plays an important role in the sustainable development of agro-ecosystem in China. To evaluate the effects of biogas on agro-ecosystem from a systematic angle, we discussed the status quo of household biogas and identified its main factors that may have impacts on agro-ecosystem. An indicator framework covering environmental, social and economic aspects was established to quantify the impacts exerted by biogas project on agro-ecosystem. A case study of Gongcheng was then conducted to evaluate the combined impact of biogas project using the proposed indicator framework. Results showed that there was a notable positive effect brought by the application of biogas, and the integrated benefit has been significantly improved by 60.36%, implying that biogas as a substitute energy source can promote the sustainable level of rural areas.

Metalloid Aluminum Clusters with Fluorine

DTIC Science & Technology

2016-12-01

molecular dynamics, binding energy , siesta code, density of states, projected density of states 15. NUMBER OF PAGES 69 16. PRICE CODE 17. SECURITY...high energy density compared to explosives, but typically release this energy slowly via diffusion-limited combustion. There is recent interest in using...examine the cluster binding energy and electronic structure. Partial fluorine substitution in a prototypical aluminum-cyclopentadienyl cluster results

Federal Campuses Handbook for Net Zero Energy, Water, and Waste

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

None

In 2015, the U.S. Department of Energy’s Office Energy Efficiency and Renewable Energy (EERE) defined a zero energy campus as "an energy-efficient campus where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy." This handbook is focused on applying the EERE definition of zero energy campuses to federal sector campuses. However, it is not intended to replace, substitute, or modify any statutory or regulatory requirements and mandates.

Federal New Buildings Handbook for Net Zero Energy, Water, and Waste

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

None

In 2015, the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) defined zero energy buildings as "an energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy." This document is focused on applying EERE’s definition of zero energy buildings to federal sector new buildings. However, it is not intended to replace, substitute, or modify any statutory or regulatory requirements and mandates.

Limited impact on decadal-scale climate change from increased use of natural gas.

PubMed

McJeon, Haewon; Edmonds, Jae; Bauer, Nico; Clarke, Leon; Fisher, Brian; Flannery, Brian P; Hilaire, Jérôme; Krey, Volker; Marangoni, Giacomo; Mi, Raymond; Riahi, Keywan; Rogner, Holger; Tavoni, Massimo

2014-10-23

The most important energy development of the past decade has been the wide deployment of hydraulic fracturing technologies that enable the production of previously uneconomic shale gas resources in North America. If these advanced gas production technologies were to be deployed globally, the energy market could see a large influx of economically competitive unconventional gas resources. The climate implications of such abundant natural gas have been hotly debated. Some researchers have observed that abundant natural gas substituting for coal could reduce carbon dioxide (CO2) emissions. Others have reported that the non-CO2 greenhouse gas emissions associated with shale gas production make its lifecycle emissions higher than those of coal. Assessment of the full impact of abundant gas on climate change requires an integrated approach to the global energy-economy-climate systems, but the literature has been limited in either its geographic scope or its coverage of greenhouse gases. Here we show that market-driven increases in global supplies of unconventional natural gas do not discernibly reduce the trajectory of greenhouse gas emissions or climate forcing. Our results, based on simulations from five state-of-the-art integrated assessment models of energy-economy-climate systems independently forced by an abundant gas scenario, project large additional natural gas consumption of up to +170 per cent by 2050. The impact on CO2 emissions, however, is found to be much smaller (from -2 per cent to +11 per cent), and a majority of the models reported a small increase in climate forcing (from -0.3 per cent to +7 per cent) associated with the increased use of abundant gas. Our results show that although market penetration of globally abundant gas may substantially change the future energy system, it is not necessarily an effective substitute for climate change mitigation policy.

Resources and economic growth: the American future--a dialogue. [Debate of geologist, physicist, and systems analyst

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

Meadows, D.L.; Weinberg, A.M.; Boyd, J.

Geologist James Boyd, physicist Alvin Weinberg, and systems analyst Dennis Meadows participated in a debate at which they forecast the cost and availability of world resources. Highlights of the debate and questions and comments from their audience are presented here. A range of optimism is evident in the predictions. Boyd foresees that energy and resource problems will be solved by technology, while Meadows contends that no solutions are possible until institutional and political constraints are lifted to allow resource development. Weinberg takes a middle view and proposes substitution of new resources for those, like fossil fuels, that are nearing depletion.more » The role of the market system is debated with disagreement over whether energy development should or can respond to a free market--and whether per capita energy consumption will increase or decline with limited economic growth. Policies governing access to fossil fuels and metals in the future are felt to be central to the issue. (DCK)« less

20 CFR 30.103 - How does a claimant make sure that OWCP has the evidence necessary to process the claim?

Code of Federal Regulations, 2013 CFR

2013-04-01

... WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR ENERGY EMPLOYEES OCCUPATIONAL ILLNESS COMPENSATION PROGRAM ACT OF 2000 CLAIMS FOR COMPENSATION UNDER THE ENERGY EMPLOYEES OCCUPATIONAL ILLNESS COMPENSATION... substitute forms. Form No. Title (1) EE-1 Claim for Benefits Under the Energy Employees Occupational Illness...

C-glycosylation reactions of sulfur-substituted glycosyl donors: evidence against the role of neighboring-group participation.

PubMed

Beaver, Matthew G; Billings, Susan B; Woerpel, K A

2008-02-13

Nucleophilic substitution reactions of C-4 sulfur-substituted tetrahydropyran acetals revealed that neighboring-group participation does not control product formation. Spectroscopic evidence for the formation of an intermediate sulfonium ion is provided, as are data from nucleophilic substitution reactions demonstrating that products are formed from oxocarbenium ion intermediates. The selectivity was not sensitive to solvent or to which Lewis acid was employed. The identity of the heteroatom at the C-4 position also did not significantly impact diastereoselectivity. Consequently, neighboring-group participation was not responsible for the formation of either the major or the minor products. These studies implicate a Curtin-Hammett kinetic scenario in which the formation of a low-energy intermediate does not necessitate its involvement in the product-forming pathway.

Effect of Ni and Ti substitutions on Li1.05Mn2O4-δ electrical conductivities at high temperature

NASA Astrophysics Data System (ADS)

Abe, Satoko; Iwasaki, Shoko; Shimonishi, Yuta; Komine, Shigeki; Munakata, Fumio

2016-10-01

Samples of Li1.05Mn2O4-δ, Li1.05Mn1.5Ni0.5O4-δ, and Li1.05Mn1.0Ni0.5Ti0.5O4-δ were prepared by a solid-state reaction technique and ultimately refined to a space group Fd-3m of spinel structure by the Rietveld method using synchrotron powder X-ray diffraction data. Comparison of lattice constants suggested that Ni-substitution increased the covalency in the bonding of MO6 (M: metal ion at 16d site) octahedrals, but Ni/Ti co-substitution decreased the covalency of M-O bonds and introduced structural distortion. Electrical conductivity measurements by a four-probe method resulted in the determination that electrical conduction (within all samples) exhibits a nonadiabatic hopping process at high temperatures. The activation energies of Li1.05Mn2O4-δ and Li1.05Mn1.5Ni0.5O4-δ were found to be of similar values. The Ni/Ti co-substituted sample of Li1.05Mn1.0Ni0.5Ti0.5O4-δ, on the other hand, showed the highest activation energy among all the measured samples. Substitution reduced the electrical conductivity relative to Li1.05Mn2O4-δ; furthermore, both the substituted samples (Li1.05Mn1.5Ni0.5O4-δ and Li1.05Mn1.0Ni0.5Ti0.5O4-δ) were found to exhibit functional independence from oxygen partial pressure (PO2).

Modulation of structural, electrical, and magnetic features with dilute Zr substitution in Bi0.8La0.2Fe1-xZrxO3 system

NASA Astrophysics Data System (ADS)

Usama, Hasan M.; Akter, Ayesha; Zubair, M. A.

2017-12-01

A significant structural modification and enhancement of the electrical and magnetic properties with dilute substitution of Zr (≤1 mol. %) in the Bi0.8La0.2Fe1-xZrxO3 system has been reported. A mixture of rhombohedral and orthorhombic phases was detected in these conventionally sintered ceramics. Transition from a leaky state to an insulating state was observed upon Zr substitution. This is the first time that a drop in the electrical conductivity as large as 6 orders of magnitude for doping as small as 0.25 mol. % in bismuth ferrite systems has been reported. An investigation on the nature of this abrupt transition revealed the dominant role of defects. A proper consideration of possible defect reactions taking place during and after sintering satisfactorily accounts for the observed modulation in the electrical properties. Both AC and DC measurements indicate that, before Zr substitution, p-type hopping conduction prevails with an activation energy as low as ˜0.57 eV, whereas the Zr substitution makes oxide ion migration the central mechanism for conduction with the activation energy of ˜0.96-1.08 eV. In contrast to that, the magnetic properties of the compounds experience a more subtle effect; a gradual modification of saturation magnetization and coercivity with Zr substitution is observed. Curve fitting of the magnetic hysteresis loops not only allowed extraction of three separate contributions from the magnetic response but also helped to explain the effects of Zr on the magnetic properties. Modifications of structural characteristics and magnetic anisotropy of the samples are believed to be the primary driving force behind the improvement in the magnetic properties.

Driving force analysis of proton tunnelling across a reactivity series for an enzyme-substrate complex.

PubMed

Hothi, Parvinder; Hay, Sam; Roujeinikova, Anna; Sutcliffe, Michael J; Lee, Michael; Leys, David; Cullis, Paul M; Scrutton, Nigel S

2008-11-24

Quantitative structure-activity relationships are widely used to probe C-H bond breakage by quinoprotein enzymes. However, we showed recently that p-substituted benzylamines are poor reactivity probes for the quinoprotein aromatic amine dehydrogenase (AADH) because of a requirement for structural change in the enzyme-substrate complex prior to C-H bond breakage. This rearrangement is partially rate limiting, which leads to deflated kinetic isotope effects for p-substituted benzylamines. Here we report reactivity (driving force) studies of AADH with p-substituted phenylethylamines for which the kinetic isotope effect (approximately 16) accompanying C-H/C-(2)H bond breakage is elevated above the semi-classical limit. We show bond breakage occurs by quantum tunnelling and that within the context of the environmentally coupled framework for H-tunnelling the presence of the p-substituent places greater demand on the apparent need for fast promoting motions. The crystal structure of AADH soaked with phenylethylamine or methoxyphenylethylamine indicates that the structural change identified with p-substituted benzylamines should not limit the reaction with p-substituted phenylethylamines. This is consistent with the elevated kinetic isotope effects measured with p-substituted phenylethylamines. We find a good correlation in the rate constant for proton transfer with bond dissociation energy for the reactive C-H bond, consistent with a rate that is limited by a Marcus-like tunnelling mechanism. As the driving force becomes larger, the rate of proton transfer increases while the Marcus activation energy becomes smaller. This is the first experimental report of the driving force perturbation of H-tunnelling in enzymes using a series of related substrates. Our study provides further support for proton tunnelling in AADH.

Biogas from sugar beet press pulp as substitute of fossil fuel in sugar beet factories.

PubMed

Brooks, L; Parravicini, V; Svardal, K; Kroiss, H; Prendl, L

2008-01-01

Sugar beet press pulp (SBP) accumulates as a by-product in sugar factories and it is generally silaged or dried to be used as animal food. Rising energy prices and the opening of the European Union sugar market has put pressure on the manufacturers to find alternatives for energy supply. The aim of this project was to develop a technology in the treatment of SBP that would lead to savings in energy consumption and would provide a more competitive sugar production from sugar beets. These goals were met by the anaerobic digestion of SBP for biogas production. Lab-scale experiments confirmed the suitability of SBP as substrate for anaerobic bacteria. Pilot-scale experiments focused on process optimization and procedures for a quick start up and operational control. Both single-stage and two-stage process configurations showed similar removal efficiency. A stable biogas production could be achieved in single-stage at a maximum volumetric loading rate of 10 kgCSB/(m(3) x d). Degradation efficiency was 75% for VS and 72% for COD. Average specific gas production reached 530 NL/kgCOD(SBP) or 610 NL/kgVS(SBP). (CH(4): 50 to 53%). The first large-scale biogas plant was put into operation during the sugar processing period 2007 at a Hungarian sugar factory. Digesting approximately 50% of the SBP (800 t/d, 22%TS), the biogas produced could substitute about 40% of the natural gas required for the thermal energy supply within the sugar processing. Copyright IWA Publishing 2008.

The air, carbon, water synergies and trade-offs in China's natural gas industry

NASA Astrophysics Data System (ADS)

Qin, Y.; Mauzerall, D. L.; Höglund-Isaksson, L.; Wagner, F.; Byers, E.

2017-12-01

Both energy production and consumption can simultaneously affect regional air quality, local water stress, and the global climate. Identifying air, carbon and water impacts of various energy sources and end-uses is important in determining the relative merits of various energy policies. Here, we examine the air-carbon-water interdependencies of China's six major natural gas source choices (domestic conventional natural gas, domestic coal-based synthetic natural gas (SNG), domestic shale gas, imported liquefied natural gas, imported Russian pipeline gas, and imported Central Asian pipeline gas) and three end-use coal-to-gas deployment strategies (with substitution strategies that focus in turn on air quality, carbon, and water) in 2020. On the supply side, we find that gas sources other than SNG offer national air-carbon-water co-benefits. However, we find striking air-carbon/water trade-offs for SNG at the national scale. Moreover, the use of SNG significantly increases water demand and carbon emissions in regions already suffering from the most severe water stress and the highest per capita carbon footprint. On the end-use side, gas substitution for coal can result in enormous variations in air quality, carbon, and water impacts, with notable air-carbon synergies but air-water trade-offs. Our study finds that, except for SNG, end-use choices generally have a much larger influence on air quality, carbon emissions and water use than do gas source choices. Simultaneous consideration of air, carbon, and water impacts is necessary in designing both beneficial energy development and deployment policies.

Quantifying reactivity for electrophilic aromatic substitution reactions with Hirshfeld charge.

PubMed

Liu, Shubin

2015-03-26

An electrophilic aromatic substitution is a process where one atom or group on an aromatic ring is replaced by an incoming electrophile. The reactivity and regioselectivity of this category of reactions is significantly impacted by the group that is already attached to the aromatic ring. Groups promoting substitution at the ortho/para and meta position are called ortho/para and meta directing groups, respectively. Earlier, we have shown that regioselectivity of the electrophilic aromatic substitution is dictated by the nucleophilicity of the substituted aromatic ring, which is proportional to the Hirshfeld charge on the regioselective site. Ortho/para directing groups have the largest negative charge values at the ortho/para positions, whereas meta directing groups often have the largest negative charge value at the meta position. The electron donation or acceptance feature of a substitution group is irrelevant to the regioselectivity. In this contribution, we extend our previous study by quantifying the reactivity for this kind of reactions. To that end, we examine the transition-state structure and activation energy of an identity reaction for a series of monosubstituted-benzene molecules reacting with hydrogen fluoride using BF3 as the catalyst in the gas phase. A total of 18 substitution groups will be considered, nine of which are ortho/para directing and the other nine groups meta directing. From this study, we found that the barrier height of these reactions strongly correlates with the Hirshfeld charge on the regioselective site for both ortho/para and meta directing groups, with the correlation coefficient R(2) both better than 0.96. We also discovered a less accurate correlation between the barrier height and HOMO energy. These results reconfirm the validity and effectiveness of employing the Hirshfeld charge as a reliable descriptor of both reactivity and regioselectivity for this vastly important category of chemical transformations.

Data-driven discovery of energy materials: efficient BaM2Si3O10 : Eu2+ (M = Sc, Lu) phosphors for application in solid state white lighting.

PubMed

Brgoch, Jakoah; Hasz, Kathryn; Denault, Kristin A; Borg, Christopher K H; Mikhailovsky, Alexander A; Seshadri, Ram

2014-01-01

In developing phosphors for application in solid state lighting, it is advantageous to target structures from databases with highly condensed polyhedral networks that produce rigid host compounds. Rigidity limits channels for non-radiative decay that will decrease the luminescence quantum yield. BaM(2)Si(3)O(10) (M = Sc, Lu) follows this design criterion and is studied here as an efficient Eu(2+)-based phosphor. M = Sc(3+) and Lu(3+) compounds with Eu(2+) substitution were prepared and characterized using synchrotron X-ray powder diffraction and photoluminescence spectroscopy. Substitution with Eu(2+) according to Ba(1-x)Eu(x)Sc(2)Si(3)O(10) and Ba(1-x)Eu(x)Lu(2)Si(3)O(10) results in UV-to-blue and UV-to-blue-green phosphors, respectively. Interestingly, substitution with Eu(2+) in the Lu(3+) containing material produces two emission peaks at low temperature and with 365 nm excitation, as allowed by the two substitution sites. The photoluminescence of the Sc(3+) compound is robust at high temperature, decreasing by only 25% of its room temperature intensity at 503 K, while the Lu-analogue suffers a large drop (75%) from its room temperature intensity. The decrease in emission intensity is explained as stemming from charge transfer quenching due to the short distances separating the luminescent centers on the Lu(3+) substitution site. The correlation between structure and optical response in these two compounds indicates that even though the structures are three-dimensionally connected, high symmetry is required to prevent structural distortions that could impact photoluminescence.

Biofortified β-carotene rice improves vitamin A intake and reduces the prevalence of inadequacy among women and young children in a simulated analysis in Bangladesh, Indonesia, and the Philippines.

PubMed

De Moura, Fabiana F; Moursi, Mourad; Donahue Angel, Moira; Angeles-Agdeppa, Imelda; Atmarita, Atmarita; Gironella, Glen M; Muslimatun, Siti; Carriquiry, Alicia

2016-09-01

Vitamin A deficiency continues to be a major public health problem affecting developing countries where people eat mostly rice as a staple food. In Asia, rice provides up to 80% of the total daily energy intake. We used existing data sets from Bangladesh, Indonesia, and the Philippines, where dietary intakes have been quantified at the individual level to 1) determine the rice and vitamin A intake in nonpregnant, nonlactating women of reproductive age and in nonbreastfed children 1-3 y old and 2) simulate the amount of change that could be achieved in the prevalence of inadequate intake of vitamin A if rice biofortified with β-carotene were consumed instead of the rice consumed at present. We considered a range of 4-20 parts per million (ppm) of β-carotene content and 10-70% substitution levels for the biofortified rice. Software was used to estimate usual rice and vitamin A intake for the simulation analyses. In an analysis by country, the substitution of biofortified rice for white rice in the optimistic scenario (20 ppm and 70% substitution) decreased the prevalence of vitamin A inadequacy from baseline 78% in women and 71% in children in Bangladesh. In Indonesia and the Philippines, the prevalence of inadequacy fell by 55-60% in women and dropped by nearly 30% in children from baseline. The results of the simulation analysis were striking in that even low substitution levels and modest increases in the β-carotene of rice produced a meaningful decrease in the prevalence of inadequate intake of vitamin A. Increasing the substitution levels had a greater impact than increasing the β-carotene content by >12 ppm.

DFT study of the effect of substituents on the absorption and emission spectra of Indigo

PubMed Central

2012-01-01

Background Theoretical analyses of the indigo dye molecule and its derivatives with Chlorine (Cl), Sulfur (S), Selenium (Se) and Bromine (Br) substituents, as well as an analysis of the Hemi-Indigo molecule, were performed using the Gaussian 03 software package. Results Calculations were performed based on the framework of density functional theory (DFT) with the Becke 3- parameter-Lee-Yang-Parr (B3LYP) functional, where the 6-31 G(d,p) basis set was employed. The configuration interaction singles (CIS) method with the same basis set was employed for the analysis of excited states and for the acquisition of the emission spectra. Conclusions The presented absorption and emission spectra were affected by the substitution position. When a hydrogen atom of the molecule was substituted by Cl or Br, practically no change in the absorbed and emitted energies relative to those of the indigo molecule were observed; however, when N was substituted by S or Se, the absorbed and emitted energies increased. PMID:22809100

Effect of interstitial and substitution alloying elements on the intrinsic stacking fault energy of nanocrystalline fcc-iron by atomistic simulation study

NASA Astrophysics Data System (ADS)

Mohammadzadeh, Mina; Mohammadzadeh, Roghayeh

2017-11-01

The stacking fault energy (SFE) is an important parameter in the deformation mechanism of face centered cubic (fcc) iron-based alloy. In this study, the effect of interstitial (C and N) and substitution (Nb and Ti) alloying elements on the intrinsic SFE (ISFE) of nanocrystalline iron were investigated via molecular dynamics (MD) simulation. The modified embedded atom method (MEAM) inter-atomic potential was used in the MD simulations. The results demonstrate a strong dependence of ISFE with addition of interstitial alloying elements but only a mild increase in ISFE with addition of substitution alloying elements in the composition range of 0 < {CNb, CTi} < 3 (at%). Moreover, it is shown that alloying of fcc iron with N decreases ISFE, whereas it increases significantly by addition of carbon element [0 < {CC, CN} < 3.5 (at%)]. The simulation method employed in this work shows reasonable agreement with some published experimental/calculated data.

Understanding biorefining efficiency--the case of agrifood waste.

PubMed

Kuisma, Miia; Kahiluoto, Helena; Havukainen, Jouni; Lehtonen, Eeva; Luoranen, Mika; Myllymaa, Tuuli; Grönroos, Juha; Horttanainen, Mika

2013-05-01

The aim of this study was to determine biorefining efficiency according to the choices made in the entire value chain. The importance of the share of biomass volume biorefined or products substituted was investigated. Agrifood-waste-based biorefining represented the case. Anticipatory scenarios were designed for contrasting targets and compared with the current situation in two Finnish regions. Biorefining increases nutrient and energy efficiency in comparison with current use of waste. System boundaries decisively influence the relative efficiency of biorefining designs. For nutrient efficiency, full exploitation of biomass potential and anaerobic digestion increase nutrient efficiency, but the main determinant is efficient substitution for mineral fertilisers. For energy efficiency, combustion and location of biorefining close to heat demand are crucial. Regional differences in agricultural structure, the extent of the food industry and population density have a major impact on biorefining. High degrees of exploitation of feedstock potential and substitution efficiency are the keys. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ab initio studies of isolated boron substitutional defects in graphane

NASA Astrophysics Data System (ADS)

Mapasha, R. E.; Chetty, N.

2017-10-01

We have systematically studied energetics, structural and electronic properties of different configurations of the B atoms substituting C-H pairs located on a single hexagonal ring in a graphane system using the first-principles density functional theory (DFT). A total number of 12 distinct B dopants configurations were identified and characterized. Based on the formation energy analysis, we found that relative stability of B dopants depends greatly on the defect configurations. Our results suggest that the B substitutions prefer to be distributed randomly but avoiding the formation of homo-elemental B-B bonds in a graphane system, at any concentration. Generally, the values of band gap decrease as the number of B dopants increases, but the low energy configurations have large band gaps compared to those that have homo-elemental bonds. As a result, the band gap of graphane can be fine tuned through the change in the structural arrangement of B atoms. The adequate control of the electronic structure of graphane through doping should be essential for technological device applications.

Steric Effects of Solvent Molecules on SN2 Substitution Dynamics.

PubMed

Liu, Xu; Xie, Jing; Zhang, Jiaxu; Yang, Li; Hase, William L

2017-04-20

Influences of solvent molecules on S N 2 reaction dynamics of microsolvated F - (H 2 O) n with CH 3 I, for n = 0-3, are uncovered by direct chemical dynamics simulations. The direct substitution mechanism, which is important without microsolvation, is quenched dramatically upon increasing hydration. The water molecules tend to force reactive encounters to proceed through the prereaction collision complex leading to indirect reaction. In contrast to F - (H 2 O), reaction with higher hydrated ions shows a strong propensity for ion desolvation in the entrance channel, diminishing steric hindrance for nucleophilic attack. Thus, nucleophilic substitution avoids the potential energy barrier with all of the solvent molecules intact and instead occurs through the less solvated barrier, which is energetically unexpected because the former barrier has a lower energy. The work presented here reveals a trade-off between reaction energetics and steric effects, with the latter found to be crucial in understanding how hydration influences microsolvated S N 2 dynamics.

[Industrial exploitation of renewable resources: from ethanol production to bioproducts development].

PubMed

Lopes Ferreira, Nicolas

2008-01-01

Plants, which are one of major groups of life forms, are constituted of an amazing number of molecules such as sugars, proteins, phenolic compounds etc. These molecules display multiple and complementary properties involved in various compartments of plants (structure, storage, biological activity etc.). The first uses of plants in industry were for food and feed, paper manufacturing or combustion. In the coming decades, these renewable biological materials will be the basis of a new concept: the "biorefiner" i.e. the chemical conversion of the whole plant to various products and uses. This concept, born in the 90ies, is analogous to today's petroleum refinery, which produces multiple fuels and derivative products from petroleum. Agriculture generates lots of co-products which were most often wasted. The rational use of these wasted products, which can be considered as valuable renewable materials, is now economically interesting and will contribute to the reduction of greenhouse has emissions by partially substituting for fossil fuels. Such substructures from biological waste products and transforming them into biofuels and new industrial products named "bioproducts". These compounds, such as bioplastics or biosurfactants, can replace equivalent petroleum derivatives. Towards that goal, lots of filamentous fungi, growing on a broad range of vegetable species, are able to produce enzymes adapted to the modification of these type of substrates. The best example, at least the more industrially developed to date, is the second generation biofuel technology using cellulose as a raw material. The process includes an enzymatic hydrolysis step which requires cellulases secreted from Trichoderma fungal species. This industrial development of a renewable energy will contribute to the diversification of energy sources used to transport and to the development of green chemistry which will partially substitute petrochemicals.

In-Space Transportation Propulsion Architecture Assessment

NASA Technical Reports Server (NTRS)

Woodcock, Gordon

2000-01-01

Almost all space propulsion development and application has been chemical. Aerobraking has been used at Venus and Mars, and for entry at Jupiter. One electric propulsion mission has been flown (DS-1) and electric propulsion is in general use by commercial communications satellites for stationkeeping. Gravity assist has been widely used for high-energy missions (Voyager, Galileo, Cassini, etc.). It has served as a substitute for high-energy propulsion but is limited in energy gain, and adds mission complexity as well as launch opportunity restrictions. It has very limited value for round trip missions such as humans to Mars and return. High-energy space propulsion has been researched for many years, and some major developments, such as nuclear thermal propulsion (NTP), undertaken. With the exception of solar electric propulsion at a scale of a few kilowatts, high-energy space propulsion has never been used on a mission. Most mission studies have adopted TRL 6 technology because most have looked for a near-term start. The current activity is technology planning aimed at broadening the options available to mission planners. Many of the illustrations used in this report came from various NASA sources; their use is gratefully acknowledged.

Enhanced magneto-caloric effect upon Co substitution in Ni-Mn-Sn thin films

NASA Astrophysics Data System (ADS)

Modak, Rajkumar; Raja, M. Manivel; Srinivasan, A.

2018-02-01

Mn rich Ni-Mn-Sn and Ni-Mn-Co-Sn alloy films were deposited on Si (1 0 0) substrate by dc magnetron sputtering from Ni50Mn37Sn13 alloy target at 1.8 Pa Ar pressure with 70 W dc power. Co was introduced by placing Co chips on the Ni-Mn-Sn target. As-deposited films were vacuum annealed at 823 K for 1 h. X-ray diffraction patterns of the films revealed modulated 14 M structure of the martensite phase at room temperature. Magnetic entropy change (ΔSm) across the Curie temperature of the ferromagnetic films was estimated from initial isothermal magnetization curves using Maxwell's equation. ΔSm and refrigeration capacity (RC) of Ni-Mn-Sn and Ni-Mn-Co-Sn films increased with increasing film thickness. Upon Co substitution in Mn/Sn site(s), ΔSm and RC increased more remarkably. The change is more prominent in the case of 360 nm films, wherein a 3.8-fold increase in ΔSM and 8.9-fold increase in RC was observed. Introduction of Co increased the magnetic moment and broadened the magnetic transition. These factors increased ΔSm and RC in Co substituted Ni-Mn-Sn alloy. Since TC shifted to higher temperatures with Co substitution, operating temperature of these magnetic refrigerants also shifted to higher temperature. This study indicates the possibility of developing high temperature cooling devices and waste energy harvesters using these films.

Alternative energy balances for Bulgaria to mitigate climate change

NASA Astrophysics Data System (ADS)

Christov, Christo

1996-01-01

Alternative energy balances aimed to mitigate greenhouse gas (GHG) emissions are developed as alternatives to the baseline energy balance. The section of mitigation options is based on the results of the GHG emission inventory for the 1987 1992 period. The energy sector is the main contributor to the total CO2 emissions of Bulgaria. Stationary combustion for heat and electricity production as well as direct end-use combustion amounts to 80% of the total emissions. The parts of the energy network that could have the biggest influence on GHG emission reduction are identified. The potential effects of the following mitigation measures are discussed: rehabilitation of the combustion facilities currently in operation; repowering to natural gas; reduction of losses in thermal and electrical transmission and distribution networks; penetration of new combustion technologies; tariff structure improvement; renewable sources for electricity and heat production; wasteheat utilization; and supply of households with natural gas to substitute for electricity in space heating and cooking. The total available and the achievable potentials are estimated and the implementation barriers are discussed.

Energy management strategy based on fuzzy logic for a fuel cell hybrid bus

NASA Astrophysics Data System (ADS)

Gao, Dawei; Jin, Zhenhua; Lu, Qingchun

Fuel cell vehicles, as a substitute for internal-combustion-engine vehicles, have become a research hotspot for most automobile manufacturers all over the world. Fuel cell systems have disadvantages, such as high cost, slow response and no regenerative energy recovery during braking; hybridization can be a solution to these drawbacks. This paper presents a fuel cell hybrid bus which is equipped with a fuel cell system and two energy storage devices, i.e., a battery and an ultracapacitor. An energy management strategy based on fuzzy logic, which is employed to control the power flow of the vehicular power train, is described. This strategy is capable of determining the desired output power of the fuel cell system, battery and ultracapacitor according to the propulsion power and recuperated braking power. Some tests to verify the strategy were developed, and the results of the tests show the effectiveness of the proposed energy management strategy and the good performance of the fuel cell hybrid bus.

Development of energy consumption and energy efficiency potential in the Brazilian industrial sector according to the Integrated Energy Planning Model (IEPM)

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

Tolmasquim, M.T.; Szklo, A.S.; Cohen, C.

This paper presents the development of energy consumption in the Brazilian industrial sector and energy efficiency potential based on the analysis undertaken through a model developed in the Energy Planning Program at COPPE/UFRJ, known as the Integrated Energy Planning Model (IEPM). The study starts by presenting the IEPM, which is a technical and economic parameter-based model designed to forecast energy supplies and consumption for all economic sectors in Brazil, within three scenarios. Outlines of all three scenarios are presented, as they were constructed according to certain specific assumptions. The industrial sector was broken down into eleven sub-sectors: food and beverages,more » ceramics, cement, iron and steel, mining and pelletizing, ferroalloys, non-ferrous metals and others (metallurgy), chemicals, pulp and paper, textiles and other industries (MME, 1998). All these sub-sectors will also be presented as well as the results of the scenario forecasts. Results deriving from these forecasts come from very specific studies that analyze all process steps in each sub-sector in order to propose energy replacements, efficiency improvements of structural production alterations that result in major potential energy consumption reductions. Last but not least, this paper gives the development forecasts deriving from the three scenarios over ten years, with their contributions to energy efficiency in the Brazilian industrial sector, showing that the authors can reduce energy consumption in the Brazilian industrial sector by: substituting less efficient processes by more efficient ones, through the conversion of final energy into usable energy, basically, in the cement and aluminum industries; replacing equipment and energy sources; modifying product mix of several industries (pulp and paper), assigning top priority to producing goods with higher added value that are less energy intensive, and, finally, reducing the share held by some energy intensive sectors in the industrial output.« less

Sustainable Energy Crop Production

USDA-ARS?s Scientific Manuscript database

Biofuels currently supply a small portion of the world’s energy needs but this is increasing due to mandates intended to reduce use of fossil fuels and the associated environmental impacts. However, the potentials of plant based feedstocks to substitute for fossil fuels and mitigate environmental im...

Hydroxide Degradation Pathways for Substituted Benzyltrimethyl Ammonium: A DFT Study

DOE PAGES

Long, Hai; Pivovar, Bryan S.

2014-11-01

The stability of cations used in the alkaline exchange membranes has been a major challenge. In this paper, degradation energy barriers were investigated by density functional theory for substituted benzyltrimethyl ammonium (BTMA+) cations. Findings show that electron-donating substituent groups at meta-position(s) of the benzyl ring could result in increased degradation barriers. However, after investigating more than thirty substituted BTMA+ cations, the largest improvement in degradation barrier found was only 6.7 kJ/mol. This suggests a modest (8×) improvement in stability for this type of approach may be possible, but for anything greater other approaches will need to be pursued.

Processing waste fats into a fuel oil substitute

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

Pudel, F.; Lengenfeld, P.

1993-12-31

Waste fats have a high energy potential. They also contain impurities. For example, fats used for deep-frying contain high contents of solids, water, and chlorides. The process described in this paper removes the impurities by simple processing such as screening, washing, separating, drying, and filtering. The final quality of processed fat allows its use as a fuel oil substitute, and also as a raw material for chemical production.

JPRS Report, Science & Technology, USSR: Life Sciences.

DTIC Science & Technology

1990-10-24

genesis was used to produce two mutant rhodopsins with amino acid substitutions in the C-terminal domain. The substitution of Cys-316->Ser does not...proteins, and also as a system for large scale synthesis of protein for practical use with a continuous supply of energy sources and amino acids into the...better than traditional neuroleptic analgesic in analysis of central peripheral hemodynamics, oxygen-transport, gas composition, and acid -base

Molecular field coefficients and cation distribution of substituted yttrium iron garnets

NASA Astrophysics Data System (ADS)

Röschmann, P.; Hansen, P.

1981-10-01

The saturation magnetization Ms(T) of Ga, Al, Sc, and CaVBi substituted Y3Fe5O12 (YIG) single crystals and of polycrystalline Ca/Ge and Ca/Ti substituted YIG has been investigated for 4.2 K ⩽T⩽TC. The samples were repeatedly annealed and quenched at different equilibrium temperatures 773 K⩽Te ⩽1523 K. The attained site exchange of Fe and the substituents between the a and d sites resulted in considerable changes of Ms(T). From a fit of the Néel molecular field theory to the Ms(T) data the dependence of the magnetic moments at T = 0 K and of the molecular field coefficients on the amount of nonmagnetic substitutions on the a and d sites were determined. It turned out that ion-specific sets of equations are required accounting for the ''particular ion effect'' of different cation species. The cation distributions inferred from the magnetic data have been analyzed along with a thermodynamic equilibrium model. The derived site stabilizing energies for the mixed Fe-Ga and Fe-Al garnets agree well with recently reported data. New results are presented for the site stabilizing energies in Ca/Ge:YIG and for the substituents Sc and Ti with octahedral site preference.

Peak oil demand: the role of fuel efficiency and alternative fuels in a global oil production decline.

PubMed

Brandt, Adam R; Millard-Ball, Adam; Ganser, Matthew; Gorelick, Steven M

2013-07-16

Some argue that peak conventional oil production is imminent due to physical resource scarcity. We examine the alternative possibility of reduced oil use due to improved efficiency and oil substitution. Our model uses historical relationships to project future demand for (a) transport services, (b) all liquid fuels, and (c) substitution with alternative energy carriers, including electricity. Results show great increases in passenger and freight transport activity, but less reliance on oil. Demand for liquids inputs to refineries declines significantly after 2070. By 2100 transport energy demand rises >1000% in Asia, while flattening in North America (+23%) and Europe (-20%). Conventional oil demand declines after 2035, and cumulative oil production is 1900 Gbbl from 2010 to 2100 (close to the U.S. Geological Survey median estimate of remaining oil, which only includes projected discoveries through 2025). These results suggest that effort is better spent to determine and influence the trajectory of oil substitution and efficiency improvement rather than to focus on oil resource scarcity. The results also imply that policy makers should not rely on liquid fossil fuel scarcity to constrain damage from climate change. However, there is an unpredictable range of emissions impacts depending on which mix of substitutes for conventional oil gains dominance-oil sands, electricity, coal-to-liquids, or others.

Exact solution of the PPP model for correlated electronic states of tetracene and substituted tetracene.

PubMed

Pati, Y Anusooya; Ramasesha, S

2014-06-12

Tetracene is an important conjugated molecule for device applications. We have used the diagrammatic valence bond method to obtain the desired states, in a Hilbert space of about 450 million singlets and 902 million triplets. We have also studied the donor/acceptor (D/A)-substituted tetracenes with D and A groups placed symmetrically about the long axis of the molecule. In these cases, by exploiting a new symmetry, which is a combination of C2 symmetry and electron-hole symmetry, we are able to obtain their low-lying states. In the case of substituted tetracene, we find that optically allowed one-photon excitation gaps reduce with increasing D/A strength, while the lowest singlet-triplet gap is only weakly affected. In all the systems we have studied, the excited singlet state, S1, is at more than twice the energy of the lowest triplet state and the second triplet is very close to the S1 state. Thus, donor-acceptor-substituted tetracene could be a good candidate in photovoltaic device application as it satisfies energy criteria for singlet fission. We have also obtained the model exact second harmonic generation (SHG) coefficients using the correction vector method, and we find that the SHG responses increase with the increase in D/A strength.

Complex doping of group 13 elements In and Ga in caged skutterudite CoSb 3

DOE PAGES

Xi, Lili; Qiu, Yting; Zheng, Shang; ...

2014-12-12

The complex doping behavior of Ga and In in CoSb 3 has been investigated using ab initio total-energy calculations and thermodynamics. The formation energies of void filling, Sb substitution and complex dual-site occupancy defects with different charge states, and their dependence on chemical potentials of species, were studied. Results show that Ga predominantly forms dual-site 2Ga VF–Ga Sb defects and substitutes for Sb only at very high Fermi levels or electron concentrations. In, on the other hand, can play multiple roles in skutterudites, including filling in the crystalline voids, substituting for Sb atoms or forming dual-site occupancy, among which themore » fully charge-compensated dual-site defects (2In VF–In Sb and 4In VF–2In Sb) are dominant. The equilibrium concentration ratio of impurities at void-filling sites to those at Sb-substitution sites for Ga-doped CoSb 3 is very close to be 2:1, while this value markedly deviates from 2:1 for In-doped CoSb 3. Furthermore, the 2:1 ratio of Ga doping in CoSb 3 leads to low electron concentration (~2 × 10 19 cm –3) and makes the doped system a semiconductor.« less

n-type conversion of SnS by isovalent ion substitution: Geometrical doping as a new doping route

PubMed Central

Ran, Fan-Yong; Xiao, Zewen; Toda, Yoshitake; Hiramatsu, Hidenori; Hosono, Hideo; Kamiya, Toshio

2015-01-01

Tin monosulfide (SnS) is a naturally p-type semiconductor with a layered crystal structure, but no reliable n-type SnS has been obtained by conventional aliovalent ion substitution. In this work, carrier polarity conversion to n-type was achieved by isovalent ion substitution for polycrystalline SnS thin films on glass substrates. Substituting Pb2+ for Sn2+ converted the majority carrier from hole to electron, and the free electron density ranged from 1012 to 1015 cm−3 with the largest electron mobility of 7.0 cm2/(Vs). The n-type conduction was confirmed further by the position of the Fermi level (EF) based on photoemission spectroscopy and electrical characteristics of pn heterojunctions. Density functional theory calculations reveal that the Pb substitution invokes a geometrical size effect that enlarges the interlayer distance and subsequently reduces the formation energies of Sn and Pb interstitials, which results in the electron doping. PMID:26020855

Defect engineering of the electronic transport through cuprous oxide interlayers

NASA Astrophysics Data System (ADS)

Fadlallah, Mohamed M.; Eckern, Ulrich; Schwingenschlögl, Udo

2016-06-01

The electronic transport through Au-(Cu2O)n-Au junctions is investigated using first-principles calculations and the nonequilibrium Green’s function method. The effect of varying the thickness (i.e., n) is studied as well as that of point defects and anion substitution. For all Cu2O thicknesses the conductance is more enhanced by bulk-like (in contrast to near-interface) defects, with the exception of O vacancies and Cl substitutional defects. A similar transmission behavior results from Cu deficiency and N substitution, as well as from Cl substitution and N interstitials for thick Cu2O junctions. In agreement with recent experimental observations, it is found that N and Cl doping enhances the conductance. A Frenkel defect, i.e., a superposition of an O interstitial and O substitutional defect, leads to a remarkably high conductance. From the analysis of the defect formation energies, Cu vacancies are found to be particularly stable, in agreement with earlier experimental and theoretical work.

Quantum-chemical modeling of smectite clays

NASA Technical Reports Server (NTRS)

Aronowitz, S.; Coyne, L.; Lawless, J.; Rishpon, J.

1982-01-01

A self-consistent charge extended Hueckel program is used in modeling isomorphic substitution of Al(3+) by Na(+), K(+), Mg(2+), Fe(2+), and Fe(3+) in the octahedral layer of a dioctahedral smectite clay, such as montmorillonite. Upon comparison of the energies involved in the isomorphic substitution, it is found that the order for successful substitution is as follows: Al(3+), Fe(3+), Mg(2+), Fe(2+), Na(+), which is equivalent to Ca(2+), and then K(+). This ordering is found to be consistent with experimental observation. The calculations also make it possible to determine the possible penetration of metal ions into the clay's 2:1 crystalline layer. For the cases studied, this type of penetration can occur at elevated temperatures into regions where isomorphic substitution has occurred with metal ions that bear a formal charge of less than 3+. The computed behavior of the electronic structure in the presence of isomorphic substitution is found to be similar to behavior associated with semiconductors.

Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration

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

Khan, Yasin; Singh, Gaurav; Mathur, Jyotirmay

The Radiant cooling system integrated with Dedicated Outdoor Air System (DOAS) is a viable substitution for conventional all air system in order to reduce primary energy consumption, as it decouples the cooling and ventilation task. In DOAS major portion of energy is consumed in cooling coil where it dehumidifies the process supply air. This study describes an alternate solution for dehumidification, with the substitution of the desiccant wheel with solar regeneration in place of a chilled water coil based dehumidifier. In this paper, simulations were carried out using EnergyPlus on a reference medium office building to investigate the contribution ofmore » solar energy towards the total energy consumption of desiccant assisted DOAS with radiant cooling system. To evaluate the system performance and energy saving potential, desiccant based DOAS is compared with cooling coil assisted DOAS integrated with Radiant cooling system. Simulations were carried out for different solar collector area to evaluate primary energy savings. Results indicate that from 7.4 % to 28.6 % energy saving (according to different collector area) can be achieved due to the solar regeneration in desiccant assisted DOAS, the impact of different solar collector area on potential of energy savings is also described.« less

Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration

DOE PAGES

Khan, Yasin; Singh, Gaurav; Mathur, Jyotirmay; ...

2017-06-13

The Radiant cooling system integrated with Dedicated Outdoor Air System (DOAS) is a viable substitution for conventional all air system in order to reduce primary energy consumption, as it decouples the cooling and ventilation task. In DOAS major portion of energy is consumed in cooling coil where it dehumidifies the process supply air. This study describes an alternate solution for dehumidification, with the substitution of the desiccant wheel with solar regeneration in place of a chilled water coil based dehumidifier. In this paper, simulations were carried out using EnergyPlus on a reference medium office building to investigate the contribution ofmore » solar energy towards the total energy consumption of desiccant assisted DOAS with radiant cooling system. To evaluate the system performance and energy saving potential, desiccant based DOAS is compared with cooling coil assisted DOAS integrated with Radiant cooling system. Simulations were carried out for different solar collector area to evaluate primary energy savings. Results indicate that from 7.4 % to 28.6 % energy saving (according to different collector area) can be achieved due to the solar regeneration in desiccant assisted DOAS, the impact of different solar collector area on potential of energy savings is also described.« less

The Impact of Professional Development on Performance and Evaluation of Substitute Teachers in a Public School System

ERIC Educational Resources Information Center

Brown, Rhonda

2012-01-01

Research suggests that many substitute teachers do not have the educational pedagogy or teacher certification necessary to be considered highly qualified by the No Child Left Behind Act of 2001. To address that concern, professional development training for substitute teachers who lack proper certification and educational pedagogy has become an…

The Development of Substitute Object Pretense: The Differential Importance of Form and Function

ERIC Educational Resources Information Center

Hopkins, Emily J.; Smith, Eric D.; Weisberg, Deena Skolnick; Lillard, Angeline S.

2016-01-01

Substitute object pretense is one of the earliest-developing forms of pretense, and yet it changes considerably across the preschool years. By 3.5 years of age, children can pretend with substitutes that are highly dissimilar from their intended referents (Elder & Pederson, 1978), but even older children have difficulty understanding such…

Metal insulator transition in nickel substituted FeSi

NASA Astrophysics Data System (ADS)

Krishnan, M.; Mishra, Ashish; Singh, Durgesh; Venkatesh, R.; Gangrade, Mohan; Ganesan, V.

2018-04-01

Resistivity of Fe1-xNixSi has been reported. Metal Insulator transition (MIT) is observed in Nickel (Ni) substituted FeSi for x in the range from 2 to 4 percentage. Two Band Model has been employed in order to calculate activation energy and to predict how band structure renormalized with substitution of nickel in FeSi. At sufficient level of nickel concentration an impurity band forms around Fermi level and contributes to the conduction heavily at low temperatures. Concentration around x = 0.04, displays metallic property below ˜ 70 K and is quantitatively similar to systems like Fe1-xTxSi (T = Co, Mn). Metallic component thus derived from Ni substituted FeSi seems to have an unconventional temperature dependence that may be attributed to the onset of departures from Fermi liquid picture.

Transition metal-substituted cobalt ferrite nanoparticles for biomedical applications.

PubMed

Sanpo, Noppakun; Berndt, Christopher C; Wen, Cuie; Wang, James

2013-03-01

Transition metals of copper, zinc, chromium and nickel were substituted into cobalt ferrite nanoparticles via a sol-gel route using citric acid as a chelating agent. The microstructure and elemental composition were characterized using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. Phase analysis of transition metal-substituted cobalt ferrite nanoparticles was performed via X-ray diffraction. Surface wettability was measured using the water contact angle technique. The surface roughness of all nanoparticles was measured using profilometry. Moreover, thermogravimetric analysis and differential scanning calorimetry were performed to determine the temperature at which the decomposition and oxidation of the chelating agents took place. Results indicated that the substitution of transition metals influences strongly the microstructure, crystal structure and antibacterial property of the cobalt ferrite nanoparticles. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

NASA Astrophysics Data System (ADS)

Yao, Jinhuan; Li, Yanwei; Li, Xuanhai; Le, Shiru

2014-07-01

The geometric structure, electronic structure, and stability of In-substituted ZnFe2O4 (Zn7InFe16O32 and Zn8Fe15InO32) are investigated by the density functional theory at generalized gradient approximation level. Compared with the perfect ZnFe2O4 (Zn8Fe16O32), the unit cell volume of In-substituted ZnFe2O4 increases and the structure deforms slightly. The formation energy of In substitution for Zn is smaller than that of In substitution for Fe, indicating that Zn7InFe16O32 is easier to be formed than Zn8Fe15InO32. In substitution changes the properties of ZnFe2O4 from semiconducting character to metallic character. For ZnFe2O4 and In-substituted ZnFe2O4, the strength of O-Zn bond is stronger than O-Fe bond and both of them have a covalent bond character. The strength of O-In bond is similar to that of O-Zn bond in Zn7InFe16O32, but weaker than O-Fe in Zn8Fe15InO32. In substitution for Zn causes the strength of O-Fe bonds around In atom to weaken. In substitution for Fe causes the strength of O-Zn bonds around In atom to weaken obviously, while the strength of O-Fe bonds strengthen slightly.

Spectrophotometric, voltammetric and cytotoxicity studies of 2-hydroxy-5-methoxyacetophenone thiosemicarbazone and its N(4)-substituted derivatives: A combined experimental-computational study

NASA Astrophysics Data System (ADS)

Akgemci, Emine Guler; Saf, Ahmet Ozgur; Tasdemir, Halil Ugur; Türkkan, Ercan; Bingol, Haluk; Turan, Suna Ozbas; Akkiprik, Mustafa

2015-02-01

In this study, 2-hydroxy-5-methoxyacetophenone thiosemicarbazone (HMAT) and its novel N(4) substituted derivatives were synthesized and characterized by different techniques. The optical band gap of the compounds and the energy of HOMO were experimentally examined by UV-vis spectra and cyclic voltammetry measurements, respectively. Furthermore, the conformational spaces of the compounds were scanned with molecular mechanics method. The geometry optimization, HOMO and LUMO energies, the energy gap of the HOMO-LUMO, dipole moment of the compounds were theoretically calculated by the density functional theory B3LYP/6-311++G(d,p) level. The minimal electronic excitation energy and maximum wavelength calculations of the compounds were also performed by TD-DFT//B3LYP/6-311++G(d,p) level of theory. Theoretically calculated values were compared with the related experimental values. The combined results exhibit that all compounds have good electron-donor properties which affect anti-proliferative activity. The cytotoxic effects of the compounds were also evaluated against HeLa (cervical carcinoma), MCF-7 (breast carcinoma) and PC-3 (prostatic carcinoma) cell lines using the standard MTT assay. All tested compounds showed antiproliferative effect having IC50 values in different range. In comparison with that of HMAT, it was obtained that while ethyl group on 4(N)-substituted position decreased in potent anti-proliferative effect, the phenyl group on the position increased in anti-proliferative effect for the tested cancer cell line. Considering the molecular energy parameters, the cytotoxicity activities of the compounds were discussed.

Setting priorities for land management to mitigate climate change

PubMed Central

2012-01-01

Background No consensus has been reached how to measure the effectiveness of climate change mitigation in the land-use sector and how to prioritize land use accordingly. We used the long-term cumulative and average sectorial C stocks in biomass, soil and products, C stock changes, the substitution of fossil energy and of energy-intensive products, and net present value (NPV) as evaluation criteria for the effectiveness of a hectare of productive land to mitigate climate change and produce economic returns. We evaluated land management options using real-life data of Thuringia, a region representative for central-western European conditions, and input from life cycle assessment, with a carbon-tracking model. We focused on solid biomass use for energy production. Results In forestry, the traditional timber production was most economically viable and most climate-friendly due to an assumed recycling rate of 80% of wood products for bioenergy. Intensification towards "pure bioenergy production" would reduce the average sectorial C stocks and the C substitution and would turn NPV negative. In the forest conservation (non-use) option, the sectorial C stocks increased by 52% against timber production, which was not compensated by foregone wood products and C substitution. Among the cropland options wheat for food with straw use for energy, whole cereals for energy, and short rotation coppice for bioenergy the latter was most climate-friendly. However, specific subsidies or incentives for perennials would be needed to favour this option. Conclusions When using the harvested products as materials prior to energy use there is no climate argument to support intensification by switching from sawn-wood timber production towards energy-wood in forestry systems. A legal framework would be needed to ensure that harvested products are first used for raw materials prior to energy use. Only an effective recycling of biomaterials frees land for long-term sustained C sequestration by conservation. Reuse cascades avoid additional emissions from shifting production or intensification. PMID:22423646

75 FR 12533 - Combined Notice Of Filings #1

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-16

....; R.E. Ginna Nuclear Power Plant, LLC; Constellation Energy Commodities Group; Constellation Energy Commodities Group Maine; Raven Three, LLC; Raven Two, LLC; Raven One, LLC; Calvert Cliffs Nuclear Power Plant LLC. Description: Calvert Cliffs Nuclear Power Plant submits Substitute First Revised Sheet 1 et al...

Rare earth substitutional impurities in germanium: A hybrid density functional theory study

NASA Astrophysics Data System (ADS)

Igumbor, E.; Omotoso, E.; Tunhuma, S. M.; Danga, H. T.; Meyer, W. E.

2017-10-01

The Heyd, Scuseria, and Ernzerhof (HSE06) hybrid functional by means of density functional theory has been used to model the electronic and structural properties of rare earth (RE) substitutional impurities in germanium (REGe) . The formation and charge state transition energies for the REGe (RE = Ce, Pr, Er and Eu) were calculated. The energy of formation for the neutral charge state of the REGe lies between -0.14 and 3.13 eV. The formation energy result shows that the Pr dopant in Ge (PrGe) has the lowest formation energy of -0.14 eV, and is most energetically favourable under equilibrium conditions. The REGe induced charge state transition levels within the band gap of Ge. Shallow acceptor levels were induced by both the Eu (EuGe) and Pr (PrGe) dopants in Ge. The CeGe and ErGe exhibited properties of negative-U ordering with effective-U values of -0.85 and -1.07 eV, respectively.

Energy retrofit of an office building by substitution of the generation system: performance evaluation via dynamic simulation versus current technical standards

NASA Astrophysics Data System (ADS)

Testi, D.; Schito, E.; Menchetti, E.; Grassi, W.

2014-11-01

Constructions built in Italy before 1945 (about 30% of the total built stock) feature low energy efficiency. Retrofit actions in this field can lead to valuable energetic and economic savings. In this work, we ran a dynamic simulation of a historical building of the University of Pisa during the heating season. We firstly evaluated the energy requirements of the building and the performance of the existing natural gas boiler, validated with past billings of natural gas. We also verified the energetic savings obtainable by the substitution of the boiler with an air-to-water electrically-driven modulating heat pump, simulated through a cycle-based model, evaluating the main economic metrics. The cycle-based model of the heat pump, validated with manufacturers' data available only at specified temperature and load conditions, can provide more accurate results than the simplified models adopted by current technical standards, thus increasing the effectiveness of energy audits.

High Energy-Density and Reversibility of Iron Fluoride Cathode Enabled Via an Intercalation-Extrusion Reaction

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

Fan, Xiulin; Hu, Enyuan; Ji, Xiao

Iron fluoride, an intercalation-conversion cathode for lithium ion batteries, promises a high theoretical energy density of 1922 Wh Kg –1. However, poor electrochemical reversibility due to repeated breaking/reformation of metal-fluoride bonds poses a grand challenge for its practical application. Here we report that both a high reversibility over 1000 cycles and a high capacity of 420 mAh g –1 can be realized by concerted doping of cobalt and oxygen into iron fluoride. In the doped nanorods, an energy density of ~1000 Wh Kg –1 with a decay rate of 0.03% per cycle is achieved. The anion and cation’s co-substitutions thermodynamicallymore » reduce conversion-reaction potential and shift the reaction from less reversible intercalation-conversion reaction in iron fluoride to a highly reversible intercalation-extrusion reaction in doped material. Furthermore, the co-substitution strategy to tune the thermodynamic features of the reactions could be extended to other high energy conversion materials for improved performance.« less

High Energy-Density and Reversibility of Iron Fluoride Cathode Enabled Via an Intercalation-Extrusion Reaction

DOE PAGES

Fan, Xiulin; Hu, Enyuan; Ji, Xiao; ...

2018-05-30

Iron fluoride, an intercalation-conversion cathode for lithium ion batteries, promises a high theoretical energy density of 1922 Wh Kg –1. However, poor electrochemical reversibility due to repeated breaking/reformation of metal-fluoride bonds poses a grand challenge for its practical application. Here we report that both a high reversibility over 1000 cycles and a high capacity of 420 mAh g –1 can be realized by concerted doping of cobalt and oxygen into iron fluoride. In the doped nanorods, an energy density of ~1000 Wh Kg –1 with a decay rate of 0.03% per cycle is achieved. The anion and cation’s co-substitutions thermodynamicallymore » reduce conversion-reaction potential and shift the reaction from less reversible intercalation-conversion reaction in iron fluoride to a highly reversible intercalation-extrusion reaction in doped material. Furthermore, the co-substitution strategy to tune the thermodynamic features of the reactions could be extended to other high energy conversion materials for improved performance.« less

Federal Existing Buildings Handbook for Net Zero Energy, Water, and Waste

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

None

In 2015, the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) defined zero energy buildings as "an energy-efficient building where, on a source energy basis, the actual annual delivered energy is less than or equal to the on-site renewable exported energy." This handbook is focused on applying the EERE definition of zero energy buildings to existing buildings in the federal sector. However, it is not intended to replace, substitute, or modify any statutory or regulatory requirements and mandates.

Necessity for Industry-Academic Economic Geology Collaborations for Energy Critical Minerals Research and Development

NASA Astrophysics Data System (ADS)

Hitzman, M.

2012-12-01

Economic geology is a highly interdisciplinary field utilizing a diverse set of petrologic, geochemical, geophysical, and tectonic data for improved scientific understanding of element migration and concentration in the crust (ore formation). A number of elements that were once laboratory curiosities now figure prominently in new energy technologies (e.g. wind turbines, solar energy collectors). If widely deployed, such technologies have the capacity to transform the way we produce, transmit, store, and conserve energy. To meet domestic and worldwide renewable energy needs these systems must be scaled from laboratory, to demonstration, to widespread deployment. Such technologies are materials intensive. If widely deployed, the elements required by these technologies will be needed in significant quantities and shortage of these "energy critical elements" could significantly inhibit the adoption of otherwise game changing energy technologies. It is imperative to better understand the geology, metallurgy, and mining engineering of critical mineral deposits if we are to sustainably develop these new technologies. There is currently no consensus among federal and state agencies, the national and international mining industry, the public, and the U.S. academic community regarding the importance of economic geology to secure sufficient energy critical elements to undertake large-scale renewable energy development. Available federal funding for critical elements focuses on downstream areas such as metallurgy, substitutions, and recycling rather than primary deposits. Undertaking the required research to discover and mine critical element deposits in an environmentally friendly manner will require significant partnering with industry due to the current lack of federal research support.

Decomposition analysis of the waste generation and management in 30 European countries.

PubMed

Korica, Predrag; Cirman, Andreja; Žgajnar Gotvajn, Andreja

2016-11-01

An often suggested method for waste prevention is substitution of currently-used materials with materials which are less bulky, contain less hazardous components or are easier to recycle. For policy makers it is important to have tools available that provide information on the impact of this substitution on the changes in total amounts of waste generated and managed. The purpose of this paper is to see how much changes in the mix of 15 waste streams generated in eight economic sectors from 30 European countries have influenced the amounts of waste generated and managed in the period 2004-2012. In order to determine these impacts, two variations of the logarithmic mean Divisia index (LMDI) analysis model were developed and applied. The results show that the changes in the mix of waste streams in most cases did not have a considerable influence on the changes in the amounts of generated waste. In the analyses of waste sent for landfill, incineration without energy recovery, incineration with energy recovery and recovery other than energy recovery, the results also show that the changes in the mix of waste streams in most cases did not have the expected/desired influence on the changes in the amounts of managed waste. This paper provides an example on the possibilities of applying the LMDI analysis as a tool for quantifying the potential of effects which implemented or planned measures could have on the changes in waste management systems. © The Author(s) 2016.

A DFT+U study of A-site and B-site substitution in BaFeO3-δ.

PubMed

Baiyee, Zarah Medina; Chen, Chi; Ciucci, Francesco

2015-09-28

BaFeO3-δ (BFO)-based perovskites have emerged as cheap and effective oxygen electrocatalysts for oxygen reduction reaction at high temperatures. The BFO cubic phase facilitates a high oxygen deficiency and is commonly stabilised by partial substitution. Understanding the electronic mechanisms of substitution and oxygen deficiency is key to rational material design, and can be realised through DFT analysis. In this work an in-depth first principle DFT+U study is undertaken to determine site distinctive characteristics for 12.5%, Y, La and Ce substitutions in BFO. In particular, it is shown that B-site doped structures exhibit a lower energy cost for oxygen vacancy formation relative to A site doping and pristine BFO. This is attributed to the stabilisation of holes in the oxygen sub-lattice and increased covalency of the Fe-O bonds of the FeO6 octahedra in B-site-substituted BFO. Charge analysis shows that A-site substitution amounts to donor doping and consequently impedes the accommodation of other donors (i.e. oxygen vacancies). However, A-site substitution may also exhibit a higher electronic conductivity due to less lattice distortion for oxygen deficiency compared to B-site doped structures. Furthermore, analysis of the local structural effects provides physical insight into stoichiometric expansions observed for this material.

Substituting energy crops with organic wastes and agro-industrial residues for biogas production.

PubMed

Schievano, Andrea; D'Imporzano, Giuliana; Adani, Fabrizio

2009-06-01

In this study, industrial and agro-industrial by-products and residues (BRs), animal manures (AMs), and various types of organic wastes (OWs) were analyzed to evaluate their suitability as substitutes for energy crops (ECs) in biogas production. A comparison between the costs of the volume of biogas that can be produced from each substrate was presented with respect to the prices of the substrates in the Italian market. Furthermore, four different feeding mixtures were compared with a mixture of EC and swine manure (Mixture A) used in a full-scale plant in Italy. Swine manure is always included as a basic substrate in the feeding mixtures, because many of the Italian biogas plants are connected to farms. When EC were partially substituted with BR (Mixture B), the cost (0.28 euro Nm(-3)) of the volume of biogas of Mixture A dropped to 0.18 euro Nm(-3). Furthermore, when the organic fraction of municipal solid waste (OFMSW) and olive oil sludge (OS) were used as possible solutions (Mixtures C and D), the costs of the volume of biogas were -0.20 and 0.11euroNm(-3), respectively. The negative price signifies that operators earn money for treating the waste. For the fifth mix (Mixture E) of the OFMSW with a high solid substrate, such as glycerin from biodiesel production, the resulting cost of the volume of biogas produced was -0.09 euro Nm(-3). By comparing these figures, it is evident that the biogas plants at farm level are good candidates for treating organic residues of both municipalities and the agro-industrial sector in a cost-effective way, and in providing territorially diffused electric and thermal power. This may represent a potential development for agrarian economy.

A high-conduction Ge substituted Li3AsS4 solid electrolyte with exceptional low activation energy

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

Sahu, Gayatri; Rangasamy, Ezhiylmurugan; Li, Juchuan

2014-04-16

In lithium-ion conducting solid electrolytes the potential to enable high-energy-density secondary batteries and offer distinctive safety features as an advantage over traditional liquid electrolytes is shown. Achieving the combination of high ionic conductivity, low activation energy, and outstanding electrochemical stability in crystalline solid electrolytes is a challenge for the synthesis of novel solid electrolytes. We report an exceptionally low activation energy (Ea) and high room temperature superionic conductivity via facile aliovalent substitution of Li 3AsS 4 by Ge, which increased the conductivity by two orders of magnitude as compared to the parent compound. The composition Li 3.334Ge 0.334As 0.666S 4more » has a high ionic conductivity of 1.12 mScm -1 at 27°C. Local Li + hopping in this material is accompanied by distinctive low activation energy Ea of 0.17 eV being the lowest of Li + solid conductors. Finally, our study demonstrates the efficacy of surface passivation of solid electrolyte to achieve compatibility with metallic lithium electrodes.« less

Probing carbon impurities in hexagonal boron nitride epilayers

NASA Astrophysics Data System (ADS)

Uddin, M. R.; Li, J.; Lin, J. Y.; Jiang, H. X.

2017-05-01

Carbon doped hexagonal boron nitride epilayers have been grown by metal organic chemical vapor deposition. Photocurrent excitation spectroscopy has been utilized to probe the energy levels associated with carbon impurities in hexagonal boron nitride (h-BN). The observed transition peaks in photocurrent excitation spectra correspond well to the energy positions of the bandgap, substitutional donors (CB, carbon impurities occupying boron sites), and substitutional acceptors (CN, carbon impurities occupying nitrogen sites). From the observed transition peak positions, the derived energy level of CB donors in h-BN is ED ˜ 0.45 eV, which agrees well with the value deduced from the temperature dependent electrical resistivity. The present study further confirms that the room temperature bandgap of h-BN is about 6.42-6.45 eV, and the CN deep acceptors have an energy level of about 2.2-2.3 eV. The results also infer that carbon doping introduces both shallow donors (CB) and deep acceptors (CN) via self-compensation, and the energy level of carbon donors appears to be too deep to enable carbon as a viable candidate as an n-type dopant in h-BN epilayers.

Electronic Structure of Ethynyl Substituted Cyclobutadienes

NASA Astrophysics Data System (ADS)

Emmert, Frank Lee Emmert, III; Thompson, Stephanie J.; Slipchenko, Lyudmila V.

2011-06-01

We investigated the effects of ethynyl substitution on the electronic structure of cyclobutadiene. These species are involved in Bergman Cyclization reactionsand are possible intermediates in the formation of fullerenes and graphite sheets. Prediction of the electronic energy of cyclobutadiene is challenging for single-reference ab initio methods such as HF, MP2 or DFT because of Jahn-Teller distortions and the diradical character of the singlet state. We determined the vertical and adiabatic singlet-triplet energy splittings, the natural charges and spin densities in substituted cyclobutadienes, using the equations of motion spin flip coupled cluster with single and double excitations (EOM-SF-CCSD) method that accurately describes diradical states. The adiabatic singlet-triplet gaps decrease upon substituent addition, but the singlet state is always lower in energy. However, we found that the results are affected by spin-contamination of the reference state and deteriorate when an unrestricted HF reference is employed. O. L. Chapman, C. L. McIntosh, J. Pacansky, "Cyclobutadiene" J. Am. Chem. Soc. 1973, 95, (2), 614-617. N. S. Goroff, "Mechanism of Fullerene Formation." Acc. Chem. Res. 1996, 29, (2), 77-83. L.V. Slipchenko and A.I. Krylov, "Singlet-triplet gaps in diradicals by the Spin-Flip approach: A benchmark study", J. Chem. Phys. 2002, 117, 4694-4708.

DFT Studies of SN2 Dechlorination of Polychlorinated Biphenyls.

PubMed

Krzemińska, Agnieszka; Paneth, Piotr

2016-06-21

Nucleophilic dechlorination of all 209 PCBs congeners by ethylene glycol anion has been studied theoretically at the DFT level. The obtained Gibbs free energies of activation are in the range 7-22 kcal/mol. The reaction Gibbs free energies indicate that all reactions are virtually irreversible. Due to geometric constrains these reactions undergo rather untypical attack with attacking oxygen atom being nearly perpendicular to the attacked C-Cl bond. The most prone to substitution are chlorine atoms that occupy ortho- (2, 2', 6, 6') positions. These results provide extensive information on the PEG/KOH dependent PCBs degradation. They can also be used in further developments of reaction class transition state theory (RC-TST) for description of complex reactive systems encountered for example in combustion processes.

Vibrational energy on surfaces: Ultrafast flash-thermal conductance of molecular monolayers

NASA Astrophysics Data System (ADS)

Dlott, Dana

2008-03-01

Vibrational energy flow through molecules remains a perennial problem in chemical physics. Usually vibrational energy dynamics are viewed through the lens of time-dependent level populations. This is natural because lasers naturally pump and probe vibrational transitions, but it is also useful to think of vibrational energy as being conducted from one location in a molecule to another. We have developed a new technique where energy is driven into a specific part of molecules adsorbed on a metal surface, and ultrafast nonlinear coherent vibrational spectroscopy is used to watch the energy arrive at another part. This technique is the analog of a flash thermal conductance apparatus, except it probes energy flow with angstrom spatial and femtosecond temporal resolution. Specific examples to be presented include energy flow along alkane chains, and energy flow into substituted benzenes. Ref: Z. Wang, J. A. Carter, A. Lagutchev, Y. K. Koh, N.-H. Seong, D. G. Cahill, and D. D. Dlott, Ultrafast flash thermal conductance of molecular chains, Science 317, 787-790 (2007). This material is based upon work supported by the National Science Foundation under award DMR 0504038 and the Air Force Office of Scientific Research under award FA9550-06-1-0235.

Binding site feature description of 2-substituted benzothiazoles as potential AcrAB-TolC efflux pump inhibitors in E. coli.

PubMed

Yilmaz, S; Altinkanat-Gelmez, G; Bolelli, K; Guneser-Merdan, D; Ufuk Over-Hasdemir, M; Aki-Yalcin, E; Yalcin, I

2015-01-01

The resistance-nodulation-division (RND) family efflux pumps are important in the antibiotic resistance of Gram-negative bacteria. However, although a number of bacterial RND efflux pump inhibitors have been developed, there has been no clinically available RND efflux pump inhibitor to date. A set of BSN-coded 2-substituted benzothiazoles were tested alone and in combinations with ciprofloxacin (CIP) against the AcrAB-TolC overexpressor Escherichia coli AG102 clinical strain. The results indicated that the BSN compounds did not show intrinsic antimicrobial activity when tested alone. However, when used in combinations with CIP, a reversal in the antibacterial activity of CIP with up to 10-fold better MIC values was observed. In order to describe the binding site features of these BSN compounds with AcrB, docking studies were performed using the CDocker method. The performed docking poses and the calculated binding energy scores revealed that the tested compounds BSN-006, BSN-023, and BSN-004 showed significant binding interactions with the phenylalanine-rich region in the distal binding site of the AcrB binding monomer. Moreover, the tested compounds BSN-006 and BSN-023 possessed stronger binding energies than CIP, verifying that BSN compounds are acting as the putative substrates of AcrB.

Cost-efficient manufacturing process of switchable glazing based on twisted nematic LC cells

NASA Astrophysics Data System (ADS)

Kurz, Eberhard; Rau, Lothar; Frühauf, Norbert; Haase, Walter; Prskalo, Marijo; Sobek, Werner

2011-10-01

Large-area glass facades are widely spread in contemporary architecture. They meet demands for natural light illumination of rooms and satisfy esthetic requirements of modern architecture. However, larger glass facades increase transfer of energy into the building. Since this has to be compensated by the intense use of air conditioning, modulation of the energy passing through the glazing is essential. The authors have been developing a corresponding system. It consists of a modified twisted nematic (TN) liquid crystal (LC) cell which is embedded in a double glazing. Since a conventional outside film polarizer is susceptible to heat, the authors substituted this component for an inside coatable polarizer. Long term outdoor weathering tests demonstrated that the concept is viable. Part of the current research is the integration of the TN LC cell into double-glazing. A further demand for such a system is a cost-efficient manufacturing process. It has been investigated to use the coatable polarizer at the same time as an alignment layer for the liquid crystal. Aluminum zinc oxide (AZO) is to be used for the electrode material substituting conventionally used indium tin oxide (ITO) which is expensive. Currently the authors are looking into the coating process for the inside polarizer.

Effect of macronutrient ratio of the pre-starter diet on broiler performance and intermediary metabolism.

PubMed

Swennen, Q; Everaert, N; Debonne, M; Verbaeys, I; Careghi, C; Tona, K; Janssens, G P J; Decuypere, E; Bruggeman, V; Buyse, J

2010-06-01

The aim of this study was to investigate the influence of isoenergetic substitution between the three energy delivering macronutrients in pre-starter diets on performance and intermediary nutrient metabolism in broiler chickens. From hatch until 5 days of age, 600 chicks, collected during peak of hatch, were fed one of the three experimental pre-starter diets with isoenergetic (13 MJ metabolisable energy/kg) substitutions between fat (43 vs. 108 g/kg), protein (126 vs. 240 g/kg) and carbohydrates (391 vs. 510 g/kg). After 5 days, commercial grower and finisher diets were provided. Pre-starter composition influenced body weight until slaughter age, although not statistically verifiable. Broilers fed the low protein (LP) pre-starter had the lowest body weight in relation to chickens on the low carbohydrate or low fat pre-starter diet. After hatch, chicks on the LP pre-starter diet were able to use the residual yolk sac more rapidly to fulfil their protein requirement, which is reflected in small intestine and liver development. Also, plasma metabolite levels were influenced mostly by the LP pre-starter, indicating that the main focus for the requirements of newly hatched chicks should be on proteins. Furthermore, optimal nutrition during the first day's post-hatch should take into account the contribution of the yolk.

DFT study of the effect of substitution on the molecular structure of copper phthalocyanine

NASA Astrophysics Data System (ADS)

Kaur, Prabhjot; Sachdeva, Ritika; Singh, Sukhwinder; Saini, G. S. S.

2016-05-01

To study the effect of sulfonic acid group as substituent on the molecular structure of an organic compound copper Phthalocyanine, the optimized geometry, mulliken charges, energies and dipole momemts of copper phthalocyanine and copper phthalocyaninetetrasulfonic acid tetra sodium salt have been investigated using density functional theory. Also to predict the change in reactive sites after substitution, molecular electrostatic potential maps for both the molecules have been calculated.

Bluish-green BMes2-functionalized Pt(II) complexes for high efficiency PhOLEDs: impact of the BMes2 location on emission color.

PubMed

Rao, Ying-Li; Schoenmakers, Dylan; Chang, Yi-Lu; Lu, Jia-Sheng; Lu, Zheng-Hong; Kang, Youngjin; Wang, Suning

2012-09-03

New phosphorescent Pt(II) compounds based on dimesitylboron (BMes(2))-functionalized 2-phenylpyridyl (ppy) N,C-chelate ligands and an acetylacetonato ancillary ligand have been achieved. We have found that BMes(2) substitution at the 4'-position of the phenyl ring can blue-shift the phosphorescent emission energy of the Pt(II) compound by approximately 50 nm, compared to the 5'-BMes(2) substituted analogue, without substantial loss of luminescent quantum efficiencies. The emission color of the 4'-BMes(2) substituted Pt(II) compound, Pt(Bppy)(acac) (1) can be further tuned by the introduction of a substituent group at the 3'-position of the phenyl ring. A methyl substituent red-shifts the emission energy of 1 by approximately 10 nm whereas a fluoro substituent blue-shifts the emission energy by about 6 nm. Using this strategy, three bright blue-green phosphorescent Pt(II) compounds 1, 2 and 3 with emission energy at 481, 492, and 475 nm and Φ(PL)=0.43, 0.26 and 0.25, respectively, have been achieved. In addition, we have examined the impact of BMes(2) substitution on 3,5-dipyridylbenzene (dpb) N,C,N-chelate Pt(II) compounds by synthesizing compound 4, Pt(Bdpb)Cl, which has a BMes(2) group at the 4'-position of the benzene ring. Compound 4 has a phosphorescent emission band at 485 nm and Φ(PL)=0.70. Highly efficient blue-green electroluminescent (EL) devices with a double-layer structure and compounds 1, 3 or 4 as the phosphorescent dopant have been fabricated. At 100 cd m(-2) luminance, EL devices based on 1, 3 and 4 with an external quantum efficiency of 4.7, 6.5 and 13.4%, respectively, have been achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, kinetic mechanism and docking studies of vanillin derivatives as inhibitors of mushroom tyrosinase.

PubMed

Ashraf, Zaman; Rafiq, Muhammad; Seo, Sung-Yum; Babar, Mustafeez Mujtaba; Zaidi, Najam-us-Sahar Sadaf

2015-09-01

The purpose of the present study was to discover the extent of contribution to antityrosinase activity by adding hydroxy substituted benzoic acid, cinnamic acid and piperazine residues to vanillin. The study showed the transformation of vanillin into esters as shown in (4a-4d), (6a-6b), and (8a-8b). In addition, the relationship between structures of these esters and their mushroom tyrosinase inhibitory activity was explored. The kinetics of inhibition on mushroom tyrosinase by these esters was also investigated. It was found that hydroxyl substituted benzoic acid derivatives were weak inhibitors; however hydroxy or chloro substituted cinnamic acid and piperazine substituted derivatives were able to induce significant tyrosinase inhibition. The mushroom tyrosinase (PDBID 2ZWE) was docked with synthesized vanillin derivatives and their calculated binding energies were compared with experimental IC50 values which provided positive correlation. The most potent derivative 2-(4-formyl-2-methoxyphenoxy)-2-oxoethyl (2E)-3-(4-hydroxyphenyl)prop-2-enoate (6a) possesses hydroxy substituted cinnamic acid scaffold having IC50 value 16.13 μM with binding energy of -7.2 kcal/mol. The tyrosinase inhibitory activity of (6a) is comparable with standard kojic acid. Kinetic analysis indicated that compound 6a was mixed-type tyrosinase inhibitor with inhibition constant values Ki (13 μM) and Ki' (53 μM) and formed reversible enzyme inhibitor complex. The active vanillin analog (6a) was devoid of toxic effects as shown in cytotoxic studies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Structural studies of human alkaline phosphatase in complex with strontium: Implication for its secondary effect in bones

PubMed Central

Llinas, Paola; Masella, Michel; Stigbrand, Torgny; Ménez, André; Stura, Enrico A.; Le Du, Marie Hélène

2006-01-01

Strontium is used in the treatment of osteoporosis as a ranelate compound, and in the treatment of painful scattered bone metastases as isotope. At very high doses and in certain conditions, it can lead to osteomalacia characterized by impairment of bone mineralization. The osteomalacia symptoms resemble those of hypophosphatasia, a rare inherited disorder associated with mutations in the gene encoding for tissue-nonspecific alkaline phosphatase (TNAP). Human alkaline phosphatases have four metal binding sites—two for zinc, one for magnesium, and one for calcium ion—that can be substituted by strontium. Here we present the crystal structure of strontium-substituted human placental alkaline phosphatase (PLAP), a related isozyme of TNAP, in which such replacement can have important physiological implications. The structure shows that strontium substitutes the calcium ion with concomitant modification of the metal coordination. The use of the flexible and polarizable force-field TCPEp (topological and classical polarization effects for proteins) predicts that calcium or strontium has similar interaction energies at the calcium-binding site of PLAP. Since calcium helps stabilize a large area that includes loops 210–228 and 250–297, its substitution by strontium could affect the stability of this region. Energy calculations suggest that only at high doses of strontium, comparable to those found for calcium, can strontium substitute for calcium. Since osteomalacia is observed after ingestion of high doses of strontium, alkaline phosphatase is likely to be one of the targets of strontium, and thus this enzyme might be involved in this disease. PMID:16815919

Core–shell interaction and its impact on the optical absorption of pure and doped core-shell CdSe/ZnSe nanoclusters

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

Wang, Xinqin; Cui, Yingqi; Zeng, Qun

The structural, electronic, and optical properties of core-shell nanoclusters, (CdSe){sub x}@(CdSe){sub y} and their Zn-substituted complexes of x = 2–4 and y = 16–28, were studied with density functional theory calculations. The substitution was applied in the cores, the shells, and/or the whole clusters. All these clusters are characterized by their core-shell structures in which the core-shell interaction was found different from those in core or in shell, as reflected by their bondlengths, volumes, and binding energies. Moreover, the core and shell combine together to compose a new cluster with electronic and optical properties different from those of separated individuals,more » as reflected by their HOMO-LUMO gaps and optical absorptions. With the substitution of Cd by Zn, the structural, electronic, and optical properties of clusters change regularly. The binding energy increases with Zn content, attributed to the strong Zn–Se bonding. For the same core/shell, the structure with a CdSe shell/core has a narrower gap than that with a ZnSe shell/core. The optical absorption spectra also change accordingly with Zn substitution. The peaks blueshift with increasing Zn concentration, accompanying with shape variations in case large number of Cd atoms are substituted. Our calculations reveal the core-shell interaction and its influence on the electronic and optical properties of the core-shell clusters, suggesting a composition–structure–property relationship for the design of core-shell CdSe and ZnSe nanoclusters.« less

Optimal ordering quantities for substitutable deteriorating items under joint replenishment with cost of substitution

NASA Astrophysics Data System (ADS)

Mishra, Vinod Kumar

2017-09-01

In this paper we develop an inventory model, to determine the optimal ordering quantities, for a set of two substitutable deteriorating items. In this inventory model the inventory level of both items depleted due to demands and deterioration and when an item is out of stock, its demands are partially fulfilled by the other item and all unsatisfied demand is lost. Each substituted item incurs a cost of substitution and the demands and deterioration is considered to be deterministic and constant. Items are order jointly in each ordering cycle, to take the advantages of joint replenishment. The problem is formulated and a solution procedure is developed to determine the optimal ordering quantities that minimize the total inventory cost. We provide an extensive numerical and sensitivity analysis to illustrate the effect of different parameter on the model. The key observation on the basis of numerical analysis, there is substantial improvement in the optimal total cost of the inventory model with substitution over without substitution.

Halogen atom effect on the photophysical properties of substituted aza-BODIPY derivatives.

PubMed

De Simone, B C; Mazzone, G; Pirillo, J; Russo, N; Sicilia, E

2017-01-18

The influence of halogen atom substitution (Br and I), in different amounts and positions in an aza-BODIPY skeleton, on the photophysical properties of some aza-BODIPY derivatives has been investigated by using density functional theory and its time-dependent extension. The heavy atom effect on excitation energies, singlet-triplet energy gaps and spin-orbit matrix elements has been considered. The maximum absorption within the therapeutic window has been confirmed for all the aza-BODIPY derivatives. The feasible intersystem spin crossing pathways for the population of the lowest triplet state, that will depend on the values of the spin-orbit matrix elements, the energy gap as well as the orbital composition of the involved states have been found to most likely involve the S 1 and T 1 or T 2 states. The outcomes of computations support the potential therapeutic use of these compounds as photosensitizers in photodynamic therapy.

Computational study of the absorption spectrum of defected ZnS nanoparticles

NASA Astrophysics Data System (ADS)

Michos, F. I.; Sigalas, M. M.

2018-04-01

Energy levels and absorption spectra of defected ZnS nanoparticles (NPs) were calculated with Density Functional Theory (DFT) and Time Dependent DFT. Several types of defects were examined such as vacancies and substitutions. NPs with S vacancies were found to have their absorption spectra moved to lower energies well inside the visible spectrum with significantly high oscillator strength. Also, NPs with substitution of S atoms with Cl, Br, or I showed significant absorption. In general, this type of defect moves the absorption spectra in lower energies, thus bringing the absorption edge into the visible spectrum, while the unperturbed NPs have absorption edges in the UV region. In addition, ZnS NPs are made from more abundant and less toxic elements than the more commonly used CdSe NPs. For that reason, they may find significant applications in solar cells and other photonic applications, as well as in biosensing applications as biomarkers.

Development of Selective Colorimetric Probes for Hydrogen Sulfide Based on Nucleophilic Aromatic Substitution

PubMed Central

Montoya, Leticia A.; Pearce, Taylor F.; Hansen, Ryan J.; Zakharov, Lev N.; Pluth, Michael D.

2013-01-01

Hydrogen sulfide is an important biological signalling molecule and an important environmental target for detection. A major challenge in developing H2S detection methods is separating the often similar reactivity of thiols and other nucleophiles from H2S. To address this need, the nucleophilic aromatic substitution (SNAr) reaction of H2S with electron-poor aromatic electrophiles was developed as a strategy to separate H2S and thiol reactivity. Treatment of aqueous solutions of nitrobenzofurazan (7-nitro-1,2,3-benzoxadiazole, NBD) thioethers with H2S resulted in thiol extrusion and formation of nitrobenzofurazan thiol (λmax = 534 nm). This reactivity allows for unwanted thioether products to be converted to the desired nitrobenzofurazan thiol upon reaction with H2S. The scope of the reaction was investigated using a Hammett linear free energy relationship study, and the determined ρ = +0.34 is consistent with the proposed SN2Ar reaction mechanism. The efficacy of the developed probes was demonstrated in buffer and in serum with associated sub-micromolar detection limits as low as 190 nM (buffer) and 380 nM (serum). Furthermore, the sigmoidal response of nitrobenzofurazan electrophiles with H2S can be fit to accurately quantify H2S. The developed detection strategy offers a manifold for H2S detection that we foresee being applied in various future applications. PMID:23735055

Development of selective colorimetric probes for hydrogen sulfide based on nucleophilic aromatic substitution.

PubMed

Montoya, Leticia A; Pearce, Taylor F; Hansen, Ryan J; Zakharov, Lev N; Pluth, Michael D

2013-07-05

Hydrogen sulfide is an important biological signaling molecule and an important environmental target for detection. A major challenge in developing H2S detection methods is separating the often similar reactivity of thiols and other nucleophiles from H2S. To address this need, the nucleophilic aromatic substitution (SNAr) reaction of H2S with electron-poor aromatic electrophiles was developed as a strategy to separate H2S and thiol reactivity. Treatment of aqueous solutions of nitrobenzofurazan (7-nitro-1,2,3-benzoxadiazole, NBD) thioethers with H2S resulted in thiol extrusion and formation of nitrobenzofurazan thiol (λmax = 534 nm). This reactivity allows for unwanted thioether products to be converted to the desired nitrobenzofurazan thiol upon reaction with H2S. The scope of the reaction was investigated using a Hammett linear free energy relationship study, and the determined ρ = +0.34 is consistent with the proposed SN2Ar reaction mechanism. The efficacy of the developed probes was demonstrated in buffer and in serum with associated submicromolar detection limits as low as 190 nM (buffer) and 380 nM (serum). Furthermore, the sigmoidal response of nitrobenzofurazan electrophiles with H2S can be fit to accurately quantify H2S. The developed detection strategy offers a manifold for H2S detection that we foresee being applied in various future applications.

10 CFR Appendix C to Part 436 - General Operations Energy Conservation Measures

Code of Federal Regulations, 2011 CFR

2011-01-01

... use of substitutes for live steam where feasible. (23) Improvements in Waste Heat Recovery—Includes measures utilizing waste heat for other purposes. (24) Improvement in Boiler Operations—Includes energy-conserving retrofit measures for boiler operations. (25) Improved Insulation—Includes measures addressing the...

10 CFR Appendix C to Part 436 - General Operations Energy Conservation Measures

Code of Federal Regulations, 2010 CFR

2010-01-01

... use of substitutes for live steam where feasible. (23) Improvements in Waste Heat Recovery—Includes measures utilizing waste heat for other purposes. (24) Improvement in Boiler Operations—Includes energy-conserving retrofit measures for boiler operations. (25) Improved Insulation—Includes measures addressing the...

10 CFR Appendix C to Part 436 - General Operations Energy Conservation Measures

Code of Federal Regulations, 2012 CFR

2012-01-01

... use of substitutes for live steam where feasible. (23) Improvements in Waste Heat Recovery—Includes measures utilizing waste heat for other purposes. (24) Improvement in Boiler Operations—Includes energy-conserving retrofit measures for boiler operations. (25) Improved Insulation—Includes measures addressing the...

10 CFR Appendix C to Part 436 - General Operations Energy Conservation Measures

Code of Federal Regulations, 2014 CFR

2014-01-01

... use of substitutes for live steam where feasible. (23) Improvements in Waste Heat Recovery—Includes measures utilizing waste heat for other purposes. (24) Improvement in Boiler Operations—Includes energy-conserving retrofit measures for boiler operations. (25) Improved Insulation—Includes measures addressing the...

10 CFR Appendix C to Part 436 - General Operations Energy Conservation Measures

Code of Federal Regulations, 2013 CFR

2013-01-01

... use of substitutes for live steam where feasible. (23) Improvements in Waste Heat Recovery—Includes measures utilizing waste heat for other purposes. (24) Improvement in Boiler Operations—Includes energy-conserving retrofit measures for boiler operations. (25) Improved Insulation—Includes measures addressing the...

Effect of Chlorine Substitution on Sulfide Reactivity with OH Radicals

DTIC Science & Technology

2008-09-01

Single point energy: MP2/6-311+G(3df,2p) (LRG) • Zero Point Energy from a vibrational frequency analysis: MP2/6-31++G** ( ZPE ) • Extrapolated energy...E(QCI) + E(LARG) – E(SML) + ZPE • Characterize the TS • Use a three-point fit methodology – fit a harmonic potential to three CCSD single point

Theoretical prediction of morphotropic compositions in Na1/2Bi1/2TiO3-based solid solutions from transition pressures

NASA Astrophysics Data System (ADS)

Gröting, Melanie; Albe, Karsten

2014-02-01

In this article we present a method based on ab initio calculations to predict compositions at morphotropic phase boundaries in lead-free perovskite solid solutions. This method utilizes the concept of flat free energy surfaces and involves the monitoring of pressure-induced phase transitions as a function of composition. As model systems, solid solutions of Na1/2Bi1/2TiO3 with the alkali substituted Li1/2Bi1/2TiO3 and K1/2Bi1/2TiO3 and the alkaline earth substituted CaTiO3 and BaTiO3 are chosen. The morphotropic compositions are identified by determining the composition at which the phase transition pressure equals zero. In addition, we discuss the different effects of hydrostatic pressure (compression and tension) and chemical substitution on the antiphase tilts about the [111] axis (a-a-a-) present in pure Na1/2Bi1/2TiO3 and how they develop in the two solid solutions Na1/2Bi1/2TiO3-CaTiO3 and Na1/2Bi1/2TiO3-BaTiO3. Finally, we discuss the advantages and shortcomings of this simple computational approach.

Reflections on fifteen years of energy policy

NASA Astrophysics Data System (ADS)

Gibbons, John H.

1985-11-01

The events of the 1970's—both the ``energy crises'' and the measures taken to alleviate them—changed our ways of thinking about energy. We now look at energy consumption as a largely substitutable means to various ends, not a goal or a measure of progress in and of itself. Energy demand growth has dropped markedly, even as the economy has grown. But there are many issues yet to be resolved if the United States is to have a comprehensive, rotational energy strategy. This paper tackles four of them: Is there a place for continued government economic and regulatory intervention in the energy marketplace? What should be the federal role in energy research and development? What are our prospects for new discoveries in domestic oil and gas? What is the future of nuclear power in the United States? The author believes that the best way to solve our energy problems is to gauge, and then reflect in our energy policy, the true costs and benefits of energy production and consumption. He concludes that conservation investments have proven to be so rewarding that energy efficiency should be receiving a major amount of attention from energy policy makers for reasons of economic efficiency and in order to minimize the impact of future crises.

Spectroscopic studies of the mechanism of reversible photodegradation of 1-substituted aminoanthraquinone-doped polymers

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

Hung, Sheng-Ting, E-mail: Sheng-Ting.Hung@jila.colorado.edu; Clays, Koen; Department of Chemistry, University of Leuven, Leuven B-3001

2016-03-21

The mechanism of reversible photodegradation of 1-substituted aminoanthraquinones doped into poly(methyl methacrylate) and polystyrene is investigated. Time-dependent density functional theory is employed to predict the transition energies and corresponding oscillator strengths of the proposed reversibly and irreversibly damaged dye species. Ultraviolet–visible and Fourier transform infrared (FTIR) spectroscopy are used to characterize which species are present. FTIR spectroscopy indicates that both dye and polymer undergo reversible photodegradation when irradiated with a visible laser. These findings suggest that photodegradation of 1-substituted aminoanthraquinones doped in polymers originates from interactions between dyes and photoinduced thermally degraded polymers, and the metastable product may recover ormore » further degrade irreversibly.« less

2D Layered Materials of Rare-Earth Er-Doped MoS2 with NIR-to-NIR Down- and Up-Conversion Photoluminescence.

PubMed

Bai, Gongxun; Yuan, Shuoguo; Zhao, Yuda; Yang, Zhibin; Choi, Sin Yuk; Chai, Yang; Yu, Siu Fung; Lau, Shu Ping; Hao, Jianhua

2016-09-01

A 2D system of Er-doped MoS2 layered nanosheets is developed. Structural studies indicate that the Er atoms can be substitutionally introduced into MoS2 to form stable doping. Density functional theory calculation implies that the system remains stable. Both NIR-to-NIR up-conversion and down-conversion light-emissions are observed in 2D transition metal dichalcogenides, ascribed to the energy transition from Er(3+) dopants. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Enhanced red fluorescence in Sr2Si1-xGexO4:Eu3+ phosphors by the substitution of Si by Ge for white light emitting diodes

NASA Astrophysics Data System (ADS)

Huang, Lihui; Xu, Shiqing; Guo, Meiquan; Wang, Chenyue; Hua, Youjie; Zhao, Shilong; Deng, Degang; Wang, Huanping; Jia, Guohua

2012-07-01

Eu3+-doped Sr2Si1-xGexO4 (x=0-1) phosphors have been prepared by the high temperature solid-state reaction method. The luminescent properties of these phosphors were investigated. Red fluorescence of Eu3+ is enhanced gradually in the samples with increasing substitution of Si by Ge upon the excitation of 393 nm light. The intensity is increased by 50% with full substitution of Si by Ge. These results are originated from the structural changes and the phonon energy reduction in the samples due to the substitution of Si by Ge. The CIE chromaticity coordinates of the phosphors vary slightly around (0.62, 0.37) and all are in the red color region. The results indicate that these phosphors could be promising red phosphors for white light emitting diodes.

Design and synthesis of chlorinated benzothiadiazole-based polymers for efficient solar energy conversion

DOE PAGES

Hu, Zhiming; Chen, Hui; Qu, Jianfei; ...

2017-03-10

Here, chlorinated benzothiadiazide based polymers with multiple chlorine atoms has been designed and synthesized for polymer solar cells with enhanced open circuit voltage up to 0.85 V. The chlorine substitution is found to significantly adjust the band gap of the polymers, and change polymer’s orientation from random morphology of chlorine free PBT4T-2OD, to mixed face-on packing of one chlorine substituted PCBT4T-2OD, and finally to edge-on of two chlorine substituted PCCBT4T-2OD. The optimized chlorinated polymer, PCBT4T-2OD with only one chlorine atom substituted on BT moiety, has been founded to achieve the highest power conversion efficiency up to 8.20% with PC 71BM,more » which is about 68% higher than that of its non-chlorine analogues.« less

[Development of hospital-substituting forms of medical care in the Samara region].

PubMed

Galkin, R A; Pavlov, V V; Kuznetsov, S I

2000-01-01

Development of hospital-substituting forms of medical care in the Samara region is discussed, 13% of patients treated at hospitals were rendered medical care through hospital-substituting institutions, which resulted in economy of 137 million roubles. The authors make their suggestions on optimizing statistical forms of files and records to be used in registration of medical care at day-time hospitals.

Adsorption and substitution effects of Mg on the growth of calcium sulfate hemihydrate: An ab initio DFT study

NASA Astrophysics Data System (ADS)

Xin, Yan; Hou, S. C.; Xiang, Lan; Yu, Yang-Xin

2015-12-01

Calcium sulfate hemihydrate (CaSO4·0.5H2O, CSH) whiskers with high aspect ratio are promising reinforce materials which have drawn much attention. In order to obtain high quality CSH materials, effect of Mg2+ ions on properties of the (0 0 2), (2 0 0)1 and (2 0 0)2 planes of CSH is investigated using an ab initio density functional theory (DFT) with a van der Waals (vdW) dispersion-correction. The computed results show that strong adsorption and substitution effects take place between Mg2+ ion and (2 0 0)1 plane. The adsorption energies of an Mg2+ ion on the (0 0 2), (2 0 0)1 and (2 0 0)2 planes are -0.066, -0.571 and -0.047 eV, respectively. An insight into the electrostatic potential of pristine CSH planes has demonstrated that the (2 0 0)1 plane is much more negatively charged than the (0 0 2) and (2 0 0)2 planes. The energies of the substitution of a Ca atom with an Mg atom on the CSH (0 0 2), (2 0 0)1 and (2 0 0)2 planes are 1.572, 0.063 and 1.349 eV, respectively. It is found that Ca atoms on the (2 0 0)1 plane are relatively easy to be substituted by Mg atoms. The calculation results of a Ca2+ ion adsorption on the Mg-doped (2 0 0)1 plane indicate that the adsorption energies increase apparently as the doping ratio varies from 0 to 1.0. Compared with K+, Na+ and Al3+ ions, Mg2+ ion is the most promising additive to promote the growth of CSH along c axis.

Optimization of Norbornadiene Compounds for Solar Thermal Storage by First-Principles Calculations.

PubMed

Kuisma, Mikael; Lundin, Angelica; Moth-Poulsen, Kasper; Hyldgaard, Per; Erhart, Paul

2016-07-21

Molecular photoswitches capable of storing solar energy are interesting candidates for future renewable energy applications. Here, using quantum mechanical calculations, we carry out a systematic screening of crucial optical (solar spectrum match) and thermal (storage energy density) properties of 64 such compounds based on the norbornadiene-quadricyclane system. Whereas a substantial number of these molecules reach the theoretical maximum solar power conversion efficiency, this requires a strong red-shift of the absorption spectrum, which causes undesirable absorption by the photoisomer as well as reduced thermal stability. These compounds typically also have a large molecular mass, leading to low storage densities. By contrast, single-substituted systems achieve a good compromise between efficiency and storage density, while avoiding competing absorption by the photo-isomer. This establishes guiding principles for the future development of molecular solar thermal storage systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microbial bio-fuels: a solution to carbon emissions and energy crisis.

PubMed

Kumar, Arun; Kaushal, Sumit; Saraf, Shubhini A; Singh, Jay Shankar

2018-06-01

Increasing energy demand, limited fossil fuel resources and climate change have prompted development of alternative sustainable and economical fuel resources such as crop-based bio-ethanol and bio-diesel. However, there is concern over use of arable land that is used for food agriculture for creation of biofuel. Thus, there is a renewed interest in the use of microbes particularly microalgae for bio-fuel production. Microbes such as micro-algae and cyanobacteria that are used for biofuel production also produce other bioactive compounds under stressed conditions. Microbial agents used for biofuel production also produce bioactive compounds with antimicrobial, antiviral, anticoagulant, antioxidant, antifungal, anti-inflammatory and anticancer activity. Because of importance of such high-value compounds in aquaculture and bioremediation, and the potential to reduce carbon emissions and energy security, the biofuels produced by microbial biotechnology might substitute the crop-based bio-ethanol and bio-diesel production.

Essays on equity-efficiency trade offs in energy and climate policies

NASA Astrophysics Data System (ADS)

Sesmero, Juan P.

Economic efficiency and societal equity are two important goals of public policy. Energy and climate policies have the potential to affect both. Efficiency is increased by substituting low-carbon energy for fossil energy (mitigating an externality) while equity is served if such substitution enhances consumption opportunities of unfavored groups (low income households or future generations). However policies that are effective in reducing pollution may not be so effective in redistributing consumption and vice-versa. This dissertation explores potential trade-offs between equity and efficiency arising in energy and climate policies. Chapter 1 yields two important results. First, while effective in reducing pollution, energy efficiency policies may fall short in protecting future generations from resource depletion. Second, deployment of technologies that increase the ease with which capital can substitute for energy may enhance the ability of societies to sustain consumption and achieve intertemporal equity. Results in Chapter 1 imply that technologies more intensive in capital and materials and less intensive in carbon such as corn ethanol may be effective in enhancing intertemporal equity. However the effectiveness of corn ethanol (relative to other technologies) in reducing emissions will depend upon the environmental performance of the industry. Chapter 2 measures environmental efficiency of ethanol plants, identifies ways to enhance performance, and calculates the cost of such improvements based on a survey of ethanol plants in the US. Results show that plants may be able to increase profits and reduce emissions simultaneously rendering the ethanol industry more effective in tackling efficiency. Finally while cap and trade proposals are designed to correcting a market failure by reducing pollution, allocation of emission allowances may affect income distribution and, hence, intra-temporal equity. Chapter 3 proves that under plausible conditions on preferences and technology increasing efficiency requires greater transfers to low income households the higher the effect of these transfers on the price of permits and the lower their effect on the price of consumption goods. This denotes market conditions under which efficiency and equity are complementary goals.

Atomic-Resolution X-ray Energy-Dispersive Spectroscopy Chemical Mapping of Substitutional Dy Atoms in a High-Coercivity Neodymium Magnet

NASA Astrophysics Data System (ADS)

Itakura, Masaru; Watanabe, Natsuki; Nishida, Minoru; Daio, Takeshi; Matsumura, Syo

2013-05-01

We have investigated local element distributions in a Dy-doped Nd2Fe14B hot-deformed magnet by atomic-column resolution chemical mapping using an X-ray energy-dispersive spectrometer (XEDS) attached to an aberration-corrected scanning transmission electron microscope (Cs-corrected STEM). The positions of the Nd and Dy atomic columns were visualized in the XEDS maps. The substitution of Dy was limited to a surface layer 2-3 unit cells thick in the Nd2Fe14B grains, and the Dy atoms preferentially occupied the 4f-Nd sites of Nd2Fe14B. These results provide further insights into the principal mechanism governing the coercivity enhancement due to Dy doping.

Design, synthesis and nonlinear optical properties of (E)-1-(4-substituted)-3-(4-hydroxy-3-nitrophenyl) prop-2-en-1-one compounds

NASA Astrophysics Data System (ADS)

Saha, Amrita; Shukla, Vijay; Choudhury, Sudip; Jayabalan, J.

2016-06-01

A new series of (E)-1-(4-substituted)-3-(4-hydroxy-3-nitrophenyl) prop-2-en-1-one compounds have been synthesized by Claisen-Schmidt condensation reaction. Nonlinear optical characterization were carried out using z-scan technique with nanosecond pulses. These samples are found to exhibit strong nonlinear absorption at 532 nm and the nonlinear absorption coefficient of these samples exponentially increases with the increase of phonon characteristic energy. This relation speaks the role of phonon in the origin of nonlinear absorption in these compounds. The reported dependence of optical nonlinearity of the chalcone derivatives on the phonon characteristic energy will help in designing similar class of new molecules with high nonlinear coefficients.

24 CFR 574.400 - Prohibition of substitution of funds.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 3 2011-04-01 2010-04-01 true Prohibition of substitution of funds. 574.400 Section 574.400 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF...

24 CFR 574.400 - Prohibition of substitution of funds.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 3 2013-04-01 2013-04-01 false Prohibition of substitution of funds. 574.400 Section 574.400 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF...

24 CFR 574.400 - Prohibition of substitution of funds.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Prohibition of substitution of funds. 574.400 Section 574.400 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF...

24 CFR 574.400 - Prohibition of substitution of funds.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 3 2012-04-01 2012-04-01 false Prohibition of substitution of funds. 574.400 Section 574.400 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF...

24 CFR 574.400 - Prohibition of substitution of funds.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 3 2014-04-01 2013-04-01 true Prohibition of substitution of funds. 574.400 Section 574.400 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF...

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

Aldridge, James D.; Womick, Jordan M.; Rosmus, Kimberly A.

Novel quaternary lanthanide-substituted oxides of stoichiometry LnxY2-xTi2O7 (where Ln is lanthanum, neodymium, samarium, gadolinium, or ytterbium) were prepared by traditional high-temperature, solid-state techniques and characterized by X-ray powder diffraction. Samples with nominal values of x up to 1.0 were attempted. The well-studied ternary cubic pyrochlore compound yttrium titanium oxide (Y2Ti2O7, space group Fd-3m, Z = 8), served as a parent structural framework in which Ln3+ cations were substituted on the Y3+ site. Laboratory-grade X-ray powder diffraction data revealed pure quaternary pyrochlore phases for LnxY2-xTi2O7 with x ≤ 0.2. Pyrochlore phase purity was verified by Rietveld analysis using high-resolution synchrotron X-raymore » powder diffraction data when x ≤ 0.2, however, for La3+ substitution specifically, pure quaternary pyrochlore formed at x<0.1. Band gap energies on selected samples were determined using optical diffuse reflectance spectroscopy and showed that these materials can be classified as electrical insulators with indirect band gap energies around 3.7 eV.« less

Correlation and nuclear distortion effects of Cr-substituted ZnSe.

PubMed

Tablero, C

2007-04-28

There is a great deal of interest in the effect of the correlation and effect of the atomic distortion in materials with a metallic intermediate band. This band, situated within the semiconductor band gaps, would be split, thus creating two bands, a full one below the Fermi energy and an empty one above it, i.e., a metal-insulator transition. This basic electronic band structure corresponds to intermediate band materials and is characteristic of transparent-conducting oxides, up and down converters, and intermediate band solar cells. A sufficiently high density of Cr in ZnSe substituting the Zn atoms leads to a microscopic intermediate band, in which these effects will be analyzed. A Hubbard term has been included to improve the description of the many-body effect. This term modifies the bandwidth of the intermediate band, the Fermi energy, and breaks the orbital-occupation degeneracy. From the results, the intermediate band is not split within the range of Hubbard term values analyzed and for Cr substituting Zn from 0.463% to 3.125% of Cr atomic concentration.

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

Parkes, Marie V.; Sava Gallis, Dorina F.; Greathouse, Jeffery A.

Computational screening of metal-organic framework (MOF) materials for selective oxygen adsorption from air could lead to new sorbents for the oxyfuel combustion process feedstock streams. A comprehensive study on the effect of MOF metal chemistry on gas binding energies in two common but structurally disparate metal-organic frameworks has been undertaken. Dispersion-corrected density functional theory methods were used to calculate the oxygen and nitrogen binding energies with each of fourteen metals, respectively, substituted into two MOF series, M 2(dobdc) and M 3(btc) 2. The accuracy of DFT methods was validated by comparing trends in binding energy with experimental gas sorption measurements.more » A periodic trend in oxygen binding energies was found, with greater oxygen binding energies for early transition-metal-substituted MOFs compared to late transition metal MOFs; this was independent of MOF structural type. The larger binding energies were associated with oxygen binding in a side-on configuration to the metal, with concomitant lengthening of the O-O bond. In contrast, nitrogen binding energies were similar across the transition metal series, regardless of both MOF structural type and metal identity. Altogether, these findings suggest that early transition metal MOFs are best suited to separating oxygen from nitrogen, and that the MOF structural type is less important than the metal identity.« less

Photobiomodulation of a flowable matrix in a human skin ex vivo model demonstrates energy-based enhancement of engraftment integration and remodeling.

PubMed

Neves, Lia M G; Parizotto, Nivaldo A; Cominetti, Marcia R; Bayat, Ardeshir

2018-04-24

The use of dermal substitutes to treat skin defects such as ulcers has shown promising results, suggesting a potential role for skin substitutes for treating acute and chronic wounds. One of the main drawbacks with the use of dermal substitutes is the length of time from engraftment to graft take, plus the risk of contamination and failure due to this prolonged integration. Therefore, the use of adjuvant energy-based therapeutic modalities to augment and accelerate the rate of biointegration by dermal substitute engraftments is a desirable outcome. The photobiomodulation (PBM) therapy modulates the repair process, by stimulating cellular proliferation and angiogenesis. Here, we evaluated the effect of PBM on a collagen-glycosaminoglycan flowable wound matrix (FWM) in an ex vivo human skin wound model. PBM resulted in accelerated rate of re-epithelialization and organization of matrix as seen by structural arrangement of collagen fibers, and a subsequent increased expression of alpha-smooth muscle actin (α-SMA) and vascular endothelial growth factor A (VEGF-A) leading to an overall improved healing process. The use of PBM promoted a beneficial effect on the rate of integration and healing of FWM. We therefore propose that the adjuvant use of PBM may have utility in enhancing engraftment and tissue repair and be of value in clinical practice. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Do single-use medical devices containing biopolymers reduce the environmental impacts of surgical procedures compared with their plastic equivalents?

PubMed

Unger, Scott R; Hottle, Troy A; Hobbs, Shakira R; Thiel, Cassandra L; Campion, Nicole; Bilec, Melissa M; Landis, Amy E

2017-01-01

Background While petroleum-based plastics are extensively used in health care, recent developments in biopolymer manufacturing have created new opportunities for increased integration of biopolymers into medical products, devices and services. This study compared the environmental impacts of single-use disposable devices with increased biopolymer content versus typically manufactured devices in hysterectomy. Methods A comparative life cycle assessment of single-use disposable medical products containing plastic(s) versus the same single-use medical devices with biopolymers substituted for plastic(s) at Magee-Women's Hospital (Magee) in Pittsburgh, PA and the products used in four types of hysterectomies that contained plastics potentially suitable for biopolymer substitution. Magee is a 360-bed teaching hospital, which performs approximately 1400 hysterectomies annually. Results There are life cycle environmental impact tradeoffs when substituting biopolymers for petroplastics in procedures such as hysterectomies. The substitution of biopolymers for petroleum-based plastics increased smog-related impacts by approximately 900% for laparoscopic and robotic hysterectomies, and increased ozone depletion-related impacts by approximately 125% for laparoscopic and robotic hysterectomies. Conversely, biopolymers reduced life cycle human health impacts, acidification and cumulative energy demand for the four hysterectomy procedures. The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects. However, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts of products and devices made using biopolymers. Conclusions The integration of biopolymers into medical products is correlated with reductions in carcinogenic impacts, non-carcinogenic impacts and respiratory effects; however, the significant agricultural inputs associated with manufacturing biopolymers exacerbate environmental impacts.

Ab Initio Study of Aluminium Impurity and Interstitial-Substitutional Complexes in Ge Using a Hybrid Functional (HSE)

NASA Astrophysics Data System (ADS)

Igumbor, E.; Mapasha, R. E.; Meyer, W. E.

2017-07-01

The results of an ab initio modelling of aluminium substitutional impurity ({\\hbox {Al}}_Ge), aluminium interstitial in Ge [{\\hbox {I}}_Al for the tetrahedral (T) and hexagonal (H) configurations] and aluminium interstitial-substitutional pairs in Ge ({\\hbox {I}}_Al{\\hbox {Al}}_Ge) are presented. For all calculations, the hybrid functional of Heyd, Scuseria, and Ernzerhof in the framework of density functional theory was used. Defects formation energies, charge state transition levels and minimum energy configurations of the {\\hbox {Al}}_Ge, {\\hbox {I}}_Al and {\\hbox {I}}_Al{\\hbox {Al}}_Ge were obtained for -2, -1, 0, +1 and +2 charge states. The calculated formation energy shows that for the neutral charge state, the {\\hbox {I}}_Al is energetically more favourable in the T than the H configuration. The {\\hbox {I}}_Al{\\hbox {Al}}_Ge forms with formation energies of -2.37 eV and -2.32 eV, when the interstitial atom is at the T and H sites, respectively. The {\\hbox {I}}_Al{\\hbox {Al}}_Ge is energetically more favourable when the interstitial atom is at the T site with a binding energy of 0.8 eV. The {\\hbox {I}}_Al in the T configuration, induced a deep donor (+2/+1) level at EV+0.23 eV and the {\\hbox {Al}}_Ge induced a single acceptor level (0/-1) at EV+0.14 eV in the band gap of Ge. The {\\hbox {I}}_Al{\\hbox {Al}}_Ge induced double-donor levels are at E_V+0.06 and E_V+0.12 eV, when the interstitial atom is at the T and H sites, respectively. The {\\hbox {I}}_Al and {\\hbox {I}}_Al{\\hbox {Al}}_Ge exhibit properties of charge state-controlled metastability.

Liquid rocket combustor computer code development

NASA Technical Reports Server (NTRS)

Liang, P. Y.

1985-01-01

The Advanced Rocket Injector/Combustor Code (ARICC) that has been developed to model the complete chemical/fluid/thermal processes occurring inside rocket combustion chambers are highlighted. The code, derived from the CONCHAS-SPRAY code originally developed at Los Alamos National Laboratory incorporates powerful features such as the ability to model complex injector combustion chamber geometries, Lagrangian tracking of droplets, full chemical equilibrium and kinetic reactions for multiple species, a fractional volume of fluid (VOF) description of liquid jet injection in addition to the gaseous phase fluid dynamics, and turbulent mass, energy, and momentum transport. Atomization and droplet dynamic models from earlier generation codes are transplated into the present code. Currently, ARICC is specialized for liquid oxygen/hydrogen propellants, although other fuel/oxidizer pairs can be easily substituted.

Oral mucosa: an alternative epidermic cell source to develop autologous dermal-epidermal substitutes from diabetic subjects

PubMed Central

GUZMÁN-URIBE, Daniela; ALVARADO-ESTRADA, Keila Neri; PIERDANT-PÉREZ, Mauricio; TORRES-ÁLVAREZ, Bertha; SÁNCHEZ-AGUILAR, Jesus Martin; ROSALES-IBÁÑEZ, Raúl

2017-01-01

Abstract Oral mucosa has been highlighted as a suitable source of epidermal cells due to its intrinsic characteristics such as its higher proliferation rate and its obtainability. Diabetic ulcers have a worldwide prevalence that is variable (1%-11%), meanwhile treatment of this has been proven ineffective. Tissue-engineered skin plays an important role in wound care focusing on strategies such autologous dermal-epidermal substitutes. Objective The aim of this study was to obtain autologous dermal-epidermal skin substitutes from oral mucosa from diabetic subjects as a first step towards a possible clinical application for cases of diabetic foot. Material and Methods Oral mucosa was obtained from diabetic and healthy subjects (n=20 per group). Epidermal cells were isolated and cultured using autologous fibrin to develop dermal-epidermal in vitro substitutes by the air-liquid technique with autologous human serum as a supplement media. Substitutes were immunocharacterized with collagen IV and cytokeratin 5-14 as specific markers. A Student´s t- test was performed to assess the differences between both groups. Results It was possible to isolate epidermal cells from the oral mucosa of diabetic and healthy subjects and develop autologous dermal-epidermal skin substitutes using autologous serum as a supplement. Differences in the expression of specific markers were observed and the cytokeratin 5-14 expression was lower in the diabetic substitutes, and the collagen IV expression was higher in the diabetic substitutes when compared with the healthy group, showing a significant difference. Conclusion Cells from oral mucosa could be an alternative and less invasive source for skin substitutes and wound healing. A difference in collagen production of diabetic cells suggests diabetic substitutes could improve diabetic wound healing. More research is needed to determine the crosstalk between components of these skin substitutes and damaged tissues. PMID:28403359

Kinetics of photo-activated charge carriers in Sn:CdS

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

Patidar, Manju Mishra, E-mail: manjumishra.iuc@gmail.com; Gorli, V. R.; Gangrade, Mohan

2016-05-23

Kinetics of the photo-activated charge carriers has been investigated in Tin substituted Cadmium Sulphide, Cd{sub 1-x}Sn{sub x}S (x=0, 0.05, 0.10 and 0.15), thin films prepared by spray pyrolysis. X-Ray Diffraction shows an increase in strain that resulted in the decreased crystallite size upon Sn substitution. At the first sight, the photo current characteristics show a quenching effect on Sn substitution. However, survival of persistent photocurrents is seen even up to 15% of Sn substitution. Transient photo current decay could be explained with a 2τ relaxation model. CdS normally has an n-type character and the Sn doping expected to inject holemore » carriers. The two fold increase in τ{sub 1}, increase in activation energy and the decrease in photocurrents upon Sn substitution point towards a band gap cleaning scenario that include compensation and associated carrier injection dynamics. In addition Atomic Force Microscopy shows a drastic change in microstructure that modulates the carrier dynamics as a whole.« less

Correlating valence state, site preference and co-substitution to the magnetoelastic properties of cobalt ferrite

NASA Astrophysics Data System (ADS)

Nlebedim, Cajetan; Jiles, David

2015-03-01

Understanding how to influence the physics of magnetism, especially the relationship between magnetic susceptibility and stress, can be very useful in designing non-contact stress and torque sensors using magnetoelastic materials. This is particularly important considering that materials rarely occur in states desirable for direct applications. In this work we show that the magnetoelastic properties of cobalt ferrite are strongly dependent on the valence states and site preferences of substituted cations. It was found that co-substitution of magnetic and non-magnetic cations, is key to achieving simultaneous improvement in magnetostriction amplitude and strain sensitivity to applied magnetic field. Nevertheless, Curie temperature decreased, irrespective of the valence state, site preference or co-substitution. This presentation will show why tetravalent Ge resulted in superior magnetostrictive properties compared to other tetravalent, trivalent and divalent cations substituted into the crystal lattice of cobalt ferrite. This work was supported by the U.S. DOE, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division. The research was performed at Ames Laboratory, operated for the USDoE by Iowa State University (Contract #DE-AC02-07CH11358).

Green and energy-efficient methods for the production of metallic nanoparticles

PubMed Central

Naghdi, Mitra; Taheran, Mehrdad; Verma, M; Surampalli, R Y; Valero, J R

2015-01-01

Summary In the last decade, researchers paid great attention to the concept of “Green Chemistry”, which aims at development of efficient methods for the synthesis of nanoparticles (NPs) in terms of the least possible impact on human life and environment. Generally, several reagents including precursors, reducing agents, stabilizing agents and solvents are used for the production of NPs and in some cases, energy is needed to reach the optimum temperature for reduction. Therefore, to develop a green approach, researchers had the opportunity to investigate eco-friendly reagents and new energy transfer techniques. In order to substitute the harmful reagents with green ones, researchers worked on different types of saccharides, polyols, carboxylic acids, polyoxometalates and extracts of various plants that can play the role of reducers, stabilizers or solvents. Also, there are some reports on using ultraviolet (UV), gamma and microwave irradiation that are capable of reducing and provide uniform heating. According to the literature, it is possible to use green reagents and novel energy transfer techniques for production of NPs. However, these new synthesis routes should be optimized in terms of performance, cost, product quality (shape and size distribution) and scale-up capability. This paper presents a review on most of the employed green reagents and new energy transfer techniques for the production of metallic NPs. PMID:26734527

Green and energy-efficient methods for the production of metallic nanoparticles.

PubMed

Naghdi, Mitra; Taheran, Mehrdad; Brar, Satinder Kaur; Verma, M; Surampalli, R Y; Valero, J R

2015-01-01

In the last decade, researchers paid great attention to the concept of "Green Chemistry", which aims at development of efficient methods for the synthesis of nanoparticles (NPs) in terms of the least possible impact on human life and environment. Generally, several reagents including precursors, reducing agents, stabilizing agents and solvents are used for the production of NPs and in some cases, energy is needed to reach the optimum temperature for reduction. Therefore, to develop a green approach, researchers had the opportunity to investigate eco-friendly reagents and new energy transfer techniques. In order to substitute the harmful reagents with green ones, researchers worked on different types of saccharides, polyols, carboxylic acids, polyoxometalates and extracts of various plants that can play the role of reducers, stabilizers or solvents. Also, there are some reports on using ultraviolet (UV), gamma and microwave irradiation that are capable of reducing and provide uniform heating. According to the literature, it is possible to use green reagents and novel energy transfer techniques for production of NPs. However, these new synthesis routes should be optimized in terms of performance, cost, product quality (shape and size distribution) and scale-up capability. This paper presents a review on most of the employed green reagents and new energy transfer techniques for the production of metallic NPs.

Molecular symmetry determines the mechanism of a very efficient ultrafast excitation-to-heat conversion in Ni-substituted chlorophylls.

PubMed

Pilch, Mariusz; Dudkowiak, Alina; Jurzyk, Barbara; Lukasiewicz, Jędrzej; Susz, Anna; Stochel, Grażyna; Fiedor, Leszek

2013-01-01

In the Ni-substituted chlorophylls, an ultrafast (<60 fs) deactivation channel is created, which is not present in Ni-porphyrins. This observation prompted us to investigate in detail the mechanism of excitation-to-heat conversion in Ni-substituted chlorophylls, experimentally, using time-resolved laser-induced optoacoustic spectroscopy, and theoretically, using group theory approach. The Ni-substituted chlorophylls show exceptional photostability and the optoacoustic measurements confirm the prompt and very efficient (100%) excitation-into-heat conversion in these complexes. Considering their excellent spectral properties and the loss-free excitation-into-heat conversion they are likely to become a new class of versatile photocalorimetric references. The curious features of the Ni-substituted chlorophylls originate from the symmetry of a ligand field created in the central cavity. The central N-Ni(2+) bonds, formed via the donation of two electrons from each of the sp(2) orbitals of two central nitrogens to an empty [Formula: see text] hybrid centered on Ni(2+), have a considerable covalent character. The extreme rate of excited state relaxation is then not due to a ladder of the metal centered d-states, often invoked in metalloporphyrins, but seems to result from a peculiar topology of the potential energy surface (a saddle-shaped crossing) due to the covalent character of the N-Ni(2+) bonds. This is confirmed by a strong 0→0 character of electronic transitions in these complexes indicating a similarity of their equilibrium geometries in the ground (S(0)) and the excited states (both Q(X) and Q(Y)). The excitation energy is very efficiently converted into molecular vibrations and dissipated as heat, involving the central Ni(2+). These Ni-substituted pigments pose a fine exemplification of symmetry control over properties of excited states of transition metal complexes. Copyright © 2012. Published by Elsevier B.V.

Substitution of water or fresh juice for bottled juice and type 2 diabetes incidence: The SUN cohort study.

PubMed

Fresan, U; Gea, A; Bes-Rastrollo, M; Basterra-Gortari, F J; Carlos, S; Martinez-Gonzalez, M A

2017-10-01

The relationship between juice consumption and type 2 diabetes (T2D) has not been widely evidenced. Our aims were to prospectively evaluate the associations with T2D incidence of: 1) isovolumetric substitution of a water serving/day for one of fruit juice (different types), and of fresh fruit juice for its bottled version; 2) consumption of total, fresh or bottled juice; 3) energy intake from juices. We followed 17,518 adults without T2D at baseline. Beverage consumption was assessed at baseline through a validated food-frequency questionnaire. The outcome was T2D incidence, according to American Diabetes Association's criteria. During a median follow-up of 10.2 years, 142 incident cases of T2D were identified. In substitution models, the substitution of water for bottled juice was associated with a lower T2D incidence, and also if the replacement was done by fresh juice, or especially fresh orange juice [HR 0.75 (95% CI 0.57-0.99), 0.65 (95% CI 0.43-0.98) and 0.56 (95% CI 0.34-0.92); respectively]. Each additional serving/day of bottled juice was directly associated with T2D incidence [HR 1.33 (95% CI 1.01-1.75)]. No significant association was observed for energy coming for bottled juice [HR 1.74 (95% CI 0.94-3.20)]. Our results suggest that isovolumetric substitution of water or fresh juice for bottled juice was inversely associated with T2D incidence in a long-term prospective study. Thus, these substitutions could be useful to tackle the diabetes epidemic. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Chapter 8: Estimating net greenhouse gas (GHG) emissions from wood energy use; Issues and the current state of knowledge

Treesearch

Prakash Nepal; Kenneth E. Skog

2014-01-01

Use of woody biomass from sustainably managed sources to produce energy is considered an important strategy to mitigate climate change because the resource is renewable (biomass regrowth on land recaptures emitted carbon dioxide (CO2) due to biomass burning) and can substitute for fossil-fuel-based energy such as coal and natural gas. However,...

The impact of biomass energy consumption on pollution: evidence from 80 developed and developing countries.

PubMed

Solarin, Sakiru Adebola; Al-Mulali, Usama; Gan, Gerald Goh Guan; Shahbaz, Muhammad

2018-05-30

The aim of this research is to explore the effect of biomass energy consumption on CO 2 emissions in 80 developed and developing countries. To achieve robustness, the system generalised method of moment was used and several control variables were incorporated into the model including real GDP, fossil fuel consumption, hydroelectricity production, urbanisation, population, foreign direct investment, financial development, institutional quality and the Kyoto protocol. Relying on the classification of the World Bank, the countries were categorised to developed and developing countries. We also used a dynamic common correlated effects estimator. The results consistently show that biomass energy as well as fossil fuel consumption generate more CO 2 emissions. A closer look at the results show that a 100% increase in biomass consumption (tonnes per capita) will increase CO 2 emissions (metric tons per capita) within the range of 2 to 47%. An increase of biomass energy intensity (biomass consumption in tonnes divided by real gross domestic product) of 100% will increase CO 2 emissions (metric tons per capita) within the range of 4 to 47%. An increase of fossil fuel consumption (tonnes of oil equivalent per capita) by 100% will increase CO 2 emissions (metric tons per capita) within the range of 35 to 55%. The results further show that real GDP urbanisation and population increase CO 2 emissions. However, hydroelectricity and institutional quality decrease CO 2 emissions. It is further observed that financial development, foreign direct investment and openness decrease CO 2 emissions in the developed countries, but the opposite results are found for the developing nations. The results also show that the Kyoto Protocol reduces emission and that Environmental Kuznets Curve exists. Among the policy implications of the foregoing results is the necessity of substituting fossil fuels with other types of renewable energy (such as hydropower) rather than biomass energy for reduction of emission to be achieved.

Photophysical properties of a novel axially substituted tetra-α-(pentyloxy) Titanium(IV) Phthalocyanine - Hematoxylin

NASA Astrophysics Data System (ADS)

Jiang, Yufeng; Lv, Huafei; Yu, Xinxin; Pan, Sujuan; Zhang, Tiantian; Huang, Yide; Wang, Yuhua; Xie, Shusen; Yang, Hongqin; Peng, Yiru

2017-06-01

Metal phthalocyanines (MPcs) are a very important class of widespread application compounds. They are not only used as dyes but also used as catalysts, data storage, electron charge carriers in photocopiers, photoconductors in chemical sensors, and photo-antenna devices in photosysthesis, photovoltaic cells. A particular application of Pcs is that it was used as a photosensitizers (PS) for treatment of certain cancer by photodynamic therapy of cancer and non-cancer diseases. However, the molecular aggregation of phthalocyanines, which is an intrinsic property of these large π-π conjugated systems, provides an efficient non-radioactive energy relaxation pathway, thereby shortening the excited state lifetimes, and reducing the photosensitizing and target efficiency. To overcome these problems, the introduction of axial ligands to phthalocyanine can prevent the formation of aggregation to some extend. In this paper, hematoxylin axially substituted tetra-α-(pentoxy) titanium (IV) phthalocyanine (TiPc(OC5H11)4-Hematoxylin) were characterized by elemental analysis, IR, 1H NMR, UV-Vis, fluorescence spectra. No obviously Q band change was observed after the hematoxylin was substituted at the peripheral position of substituted phthalocyanine ring. Because of the rigidity structure of the hematoxylin, the fluorescence intensity of hematoxylin peripheral substituted phthalocyanine decreased compared with free substituted phthalocyanines. The fluorescence lifetimes of axially substituted phthalocyanine was fitted to be 3.613 ns. This compound may be considered as a promising photosensitizer for PDT.

Ion-conduction mechanisms in NaSICON-type membranes for energy storage and utilization

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

McDaniel, Anthony H.; Ihlefeld, Jon F.; Bartelt, Norman Charles

2015-10-01

Next generation metal-ion conducting membranes are key to developing energy storage and utilization technologies like batteries and fuel ce lls. Sodium super-ionic conductors (aka NaSICON) are a class of compounds with AM 1 M 2 (PO 4 ) 3 stoichiometry where the choice of "A" and "M" cation varies widely. This report, which de scribes substitutional derivatives of NZP (NaZr 2 P 3 O 12 ), summarizes the accomplishments of a Laboratory D irected Research and Development (LDRD) project to analyze transport mec hanisms using a combination of in situ studies of structure, composition, and bonding, com bined with firstmore » principles theory and modeling. We developed an experimental platform and applied methods, such as synchrotron- based X-ray spectroscopies, to probe the electronic structure of compositionally well-controlled NaSICON films while in operation ( i.e ., conducting Na ions exposed to oxygen or water va por atmospheres). First principles theory and modeling were used to interpret the experimental observations and develop an enhanced understanding of atomistic processes that give rise to, and affect, ion conduction.« less

Evaluating water quality -- is it important, how can it be determined and how can it be used?

NASA Astrophysics Data System (ADS)

Leahy, P. P.

2015-12-01

Freshwater is critical to sustaining all life on Earth yet most humans take this resource for granted and often consider it a free good. However, in water-poor areas, the availability of clean drinking water limits economic development, negatively impacts human health and causes significant social instability. This was a driver for the Millennium Development Goals to include providing clean water to the developing world. Unlike other resources, another commodity cannot be substituted for water. In mineral resources, substitution is common depending on the use, for example, aluminum for steel in automotive bodies. In energy, humans can, in some instances, use natural gas instead of coal for electricity generation. Given the critical nature of freshwater for human existence, it is important that the resource be evaluated in economic terms. Although efforts to assess the value of the availability of freshwater have been developed, they are not commonly used. Water quality is also a major economic factor in availability of water resources. Quality can be prohibitively expensive to bring to acceptable standards and can easily be contaminated by human activities. Determining an economic and social value on both the availability and quality of water resources is a challenge that the hydrologic community must address at local, regional and national and even global scales to support informed policy and decision-making.

Greenhouse gas impacts of declining hydrocarbon resource quality: Depletion, dynamics, and process emissions

NASA Astrophysics Data System (ADS)

Brandt, Adam Robert

This dissertation explores the environmental and economic impacts of the transition to hydrocarbon substitutes for conventional petroleum (SCPs). First, mathematical models of oil depletion are reviewed, including the Hubbert model, curve-fitting methods, simulation models, and economic models. The benefits and drawbacks of each method are outlined. I discuss the predictive value of the models and our ability to determine if one model type works best. I argue that forecasting oil depletion without also including substitution with SCPs results in unrealistic projections of future energy supply. I next use information theoretic techniques to test the Hubbert model of oil depletion against five other asymmetric and symmetric curve-fitting models using data from 139 oil producing regions. I also test the assumptions that production curves are symmetric and that production is more bell-shaped in larger regions. Results show that if symmetry is enforced, Gaussian production curves perform best, while if asymmetry is allowed, asymmetric exponential models prove most useful. I also find strong evidence for asymmetry: production declines are consistently less steep than inclines. In order to understand the impacts of oil depletion on GHG emissions, I developed the Regional Optimization Model for Emissions from Oil Substitutes (ROMEO). ROMEO is an economic optimization model of investment and production of fuels. Results indicate that incremental emissions (with demand held constant) from SCPs could be 5-20 GtC over the next 50 years. These results are sensitive to the endowment of conventional oil and not sensitive to a carbon tax. If demand can vary, total emissions could decline under a transition because the higher cost of SCPs lessens overall fuel consumption. Lastly, I study the energetic and environmental characteristics of the in situ conversion process, which utilizes electricity to generate liquid hydrocarbons from oil shale. I model the energy inputs and outputs from the ICP use them to calculate the GHG emissions from the ICP. Energy outputs (as refined liquid fuel) range from 1.2 to 1.6 times the total primary energy inputs. Well-to-tank greenhouse gas emissions range from 30.6 to 37.1 gCeq./MJ of final fuel delivered, 21 to 47% larger than those from conventionally produced petroleum-based fuels.

Explicit Substitutions and All That

NASA Technical Reports Server (NTRS)

Ayala-Rincon, Mauricio; Munoz, Cesar

2000-01-01

Explicit substitution calculi are extensions of the lambda-calculus where the substitution mechanism is internalized into the theory. This feature makes them suitable for implementation and theoretical study of logic-based tools such as strongly typed programming languages and proof assistant systems. In this paper we explore new developments on two of the most successful styles of explicit substitution calculi: the lambda sigma- and lambda S(e)-calculi.

Explicit Substitutions and All That

NASA Technical Reports Server (NTRS)

Ayala-Rincon, Mauricio; Munoz, Cesar; Busnell, Dennis M. (Technical Monitor)

2000-01-01

Explicit substitution calculi are extensions of the Lambda-calculus where the substitution mechanism is internalized into the theory. This feature makes them suitable for implementation and theoretical study of logic-based tools such as strongly typed programming languages and proof assistant systems. In this paper we explore new developments on two of the most successful styles of explicit substitution calculi: the lambda(sigma)- and lambda(s(e))-calculi.

Eight Ways to Make Sure Substitute Teachers Aren't Baby-Sitters.

ERIC Educational Resources Information Center

Drury, William R.

1988-01-01

Substitutes might never be as good as regular teachers, but they still can provide high-quality instruction. Suggestions include meeting with them as a group twice a year, principal and peer support, and development workshops specifically for substitutes. (TE)

Effect of maggot (Hermetia illucens) flour in commercial feed on protein retention, energy retention, protein content, and fat content in tilapia (Oreochromis niloticus)

NASA Astrophysics Data System (ADS)

Kurniawan, D. R.; Arief, M.; Agustono; Lamid, M.

2018-04-01

Nile tilapia is a fish with a nature of breeding throughout the year and has a high adaptation. Feed is one of the most important factors that will affect the growth and the sustainability of fish. Maggot is one of the alternative feeds which has function as source of protein.The aim of this research is to ascertain the influence of maggot (Hermetia illucens) flour substitution on commercial feed which affect the retention of energy, retention of protein, and also rough fat and protein of Nile tilapia flesh. The treatment was to substitute the commercial feed with different doses of maggot flour. In this study, the amount of maggot flour substituted on commercial feed is as follows: treatment P0 (0 %), P1 (12 %), P2 (14 %), P3 (16 %) and P4 (18 %). The parameter observed in this study is an effect on to protein retention, energy retention, and also rough fat and protein in Nile tilapia flesh. The result showed the highest protein content was gained from the treatment P4 with 17.267 %. The lowest protein content was 16.344 % obtained in the treatment P0. There was an increasing protein content in Nile tilapia along with the increase of the maggot flour addition in each treatment.

Assessment of energy options for Liberia. Final report

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

Not Available

1983-11-01

Under funding from the U.S. Agency for International Development (USAID), the Oak Ridge National Laboratory provided energy planning assistance to the National Energy Committee of the Government of Liberia (GOL), West Africa, during a period of one year ending March 31, 1983. This report outlines the scope of activities of the joint GOL/USAID project and summarizes the major findings by Liberian and U.S. project participants. The study included and examination of current energy use by sector and fuel type, projections of future energy demands, and a preliminary evaluation of a variety of alternative energy resource and technology options for Liberia.more » The primary finding is that Liberia has significant opportunities for the substitution of indigenous energy resources for imported petroleum. The principal candidates are wood energy and hydroelectric power. The major alternatives for wood are gasification technology for small-scale electric and nonelectric applications (e.g., those under about 25-gigajoule/hour input requirements) and wood-fired steam electric generation for larger scale applications where hydroelectric power is unattractive. For major hydroelectric development the principal candidates are the St. Paul River Proposal and the Mano River Proposal. The Mano River Proposal is the smaller of the two and would meet Monrovia area electrical grid requirements and some iron ore mine demand for about the next two decades. An additional important finding of this study is that the Monrovia Petroleum refinery is highly uneconomical and should be closed and petroleum product imported directly. 25 tables.« less

Final Report for NIREC Renewable Energy Research & Development Project

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

Borland, Walt

This report is a compilation of progress reports and presentations submitted by NIREC to the DOE’s Solar Energy Technologies Office for award number DE-FG36-08GO88161. This compilation has been uploaded to OSTI by DOE as a substitute for the required Final Technical Report, which was not submitted to DOE by NIREC or received by DOE. Project Objective: The primary goal of NIREC is to advance the transformation of the scientific innovation of the institutional partner’s research in renewable energy into a proof of the scientific concept eventually leading to viable businesses with cost effective solutions to accelerate the widespread adoption ofmore » renewable energy. NIREC will a) select research projects that are determined to have significant commercialization potential as a result of vetting by the Technology and commercialization Advisory Board, b) assign an experienced Entrepreneur-in-Residence (EIR) to each manage the scientific commercialization-preparedness process, and c) facilitate connectivity with venture capital and other private-sector capital sources to fund the rollout, scaling and growth of the resultant renewable energy business.« less

10 CFR 30.2 - Resolution of conflict.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Resolution of conflict. 30.2 Section 30.2 Energy NUCLEAR... Provisions § 30.2 Resolution of conflict. The requirements of this part are in addition to, and not in substitution for, other requirements of this chapter. In any conflict between the requirements in this part and...

10 CFR 503.9 - Use of mixtures-general requirement for certain permanent exemptions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... exemptions. 503.9 Section 503.9 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS NEW FACILITIES... and petroleum and an alternate fuel for which an exemption under 10 CFR 503.38 (Fuel mixtures) would... substitute mixture, such other alternate fuels as OFE and the petitioner agree are reasonable to petitioner's...

48 CFR 223.7305 - Authorization and approval.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ENERGY TECHNOLOGIES, OCCUPATIONAL SAFETY, AND DRUG-FREE WORKPLACE Minimizing the Use of Materials... apply to critical defense applications if no substitute can meet performance requirements. The DoD...

Charge transfer and optical properties of trifluoromethyl substituted benzodithiophene (TFMBDT): A theoretical study

NASA Astrophysics Data System (ADS)

Sahoo, Smruti Ranjan; Sahu, Sridhar; Sharma, Sagar

2018-05-01

We present density functional study of the charge transport and optical properties of trifluoromethyl substituted benzodithiophene (TFMBDT) molecule. We found the hole reorganization energy, reduced by 0.354 eV compared to the electron reorganization energy, thus favoring the hole transport across the molecular barrier. We found the maximum tH and tL at the tilting angle 85°, to be 0.473 eV and 0.472 eV, respectively. Although, both tH and tL are found to equivalent, however, low λh can contribute to the larger hole mobility. In the TD-DFT calculation, the low energy electronic transition (H→L) was found to be accordance with the electronic HOMO-LUMO energy gap of the conjugated organic molecule. The calculated gas phase maximum absorption (λmax) of TFMBDT molecule was observed at 337.31 nm (3.67 eV) for B3LYP/6-311+G(d, p) level and 328.04 nm (3.77 eV) for PBE1PBE/6-311+G(d, p) level, which is mostly associated with HOMO→LUMO transition.

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

Steinberg, Daniel; Bielen, Dave; Eichman, Josh

Electrification of end-use services in the transportation, buildings, and industrial sectors coupled with decarbonization of electricity generation has been identified as one of the key pathways to achieving a low-carbon future in the United States. By lowering the carbon intensity of the electricity generation and substituting electricity for higher-emissions fossil fuels in end-use sectors, significant reductions in carbon dioxide emissions can be achieved. This report describes a preliminary analysis that examines the potential impacts of widespread electrification on the U.S. energy sector. We develop a set of exploratory scenarios under which electrification is aggressively pursued across all end-use sectors andmore » examine the impacts of achieving these electrification levels on electricity load patterns, total fossil energy consumption, carbon dioxide emissions, and the evolution of the U.S. power system.« less

Electronic and Photoelectron Spectroscopy of Toluene

NASA Astrophysics Data System (ADS)

Gardner, Adrian M.; Green, Alistair M.; Tame-Reyes, Victor; Wright, Timothy G.

2012-06-01

Electronic and photoelectron spectra of toluene are presented and discussed. The utilization of a recently reported scheme for assigning the normal vibrations of substituted benzenes allows these spectra to be compared to those of other molecules with unprecedented clarity. Changes in vibrational activity within a series of substituted benzene molecules will be discussed, specifically the increased rate of intramolecular vibrational energy redistribution observed in molecules where the substituent is a methyl group. A. M. Gardner and T. G. Wright, J. Chem. Phys., 135, 114305 (2011)

Acceleration of vascularized bone tissue-engineered constructs in a large animal model combining intrinsic and extrinsic vascularization.

PubMed

Weigand, Annika; Beier, Justus P; Hess, Andreas; Gerber, Thomas; Arkudas, Andreas; Horch, Raymund E; Boos, Anja M

2015-05-01

During the last decades, a range of excellent and promising strategies in Bone Tissue Engineering have been developed. However, the remaining major problem is the lack of vascularization. In this study, extrinsic and intrinsic vascularization strategies were combined for acceleration of vascularization. For optimal biomechanical stability of the defect site and simplifying future transition into clinical application, a primary stable and approved nanostructured bone substitute in clinically relevant size was used. An arteriovenous (AV) loop was microsurgically created in sheep and implanted, together with the bone substitute, in either perforated titanium chambers (intrinsic/extrinsic) for different time intervals of up to 18 weeks or isolated Teflon(®) chambers (intrinsic) for 18 weeks. Over time, magnetic resonance imaging and micro-computed tomography (CT) analyses illustrate the dense vascularization arising from the AV loop. The bone substitute was completely interspersed with newly formed tissue after 12 weeks of intrinsic/extrinsic vascularization and after 18 weeks of intrinsic/extrinsic and intrinsic vascularization. Successful matrix change from an inorganic to an organic scaffold could be demonstrated in vascularized areas with scanning electron microscopy and energy dispersive X-ray spectroscopy. Using the intrinsic vascularization method only, the degradation of the scaffold and osteoclastic activity was significantly lower after 18 weeks, compared with 12 and 18 weeks in the combined intrinsic-extrinsic model. Immunohistochemical staining revealed an increase in bone tissue formation over time, without a difference between intrinsic/extrinsic and intrinsic vascularization after 18 weeks. This study presents the combination of extrinsic and intrinsic vascularization strategies for the generation of an axially vascularized bone substitute in clinically relevant size using a large animal model. The additional extrinsic vascularization promotes tissue ingrowth and remodeling processes of the bone substitute. Extrinsic vessels contribute to faster vascularization and finally anastomose with intrinsic vasculature, allowing microvascular transplantation of the bone substitute after a shorter prevascularization time than using the intrinsic method only. It can be reasonably assumed that the usage of perforated chambers can significantly reduce the time until transplantation of bone constructs. Finally, this study paves the way for further preclinical testing for proof of the concept as a basis for early clinical applicability.

Photocatalytic CO2 reduction by Cr-substituted Ba2(In2-xCrx)O5·(H2O)δ (0.04 ≤ x ≤ 0.60)

NASA Astrophysics Data System (ADS)

Yoon, Songhak; Gaul, Michael; Sharma, Sitansh; Son, Kwanghyo; Hagemann, Hans; Ziegenbalg, Dirk; Schwingenschlogl, Udo; Widenmeyer, Marc; Weidenkaff, Anke

2018-04-01

Cr-substituted polycrystalline Ba2(In2-xCrx)O5·(H2O)δ powders (0.04 ≤ x ≤ 0.60) were synthesized by solid state reaction to investigate the relation of crystal structure, thermochemical, magnetic, and optical properties. The Cr-substitution results in an unit cell expansion and formation of the higher-symmetric tetragonal phase together with increased oxygen and hydrogen contents. Magnetic property measurements reveal that the diamagnetic pristine Ba2In2O5·(H2O)δ becomes magnetically ordered upon Cr-substitution. By UV-vis spectroscopy a gradual shift of the absorption-edge energy to lower values was observed. Numerical calculations showed that the observed bandgap narrowing was ascribed to the Cr induced states near the Fermi level. The correlation between the changes of crystal chemistry, magnetic, and optical properties of Cr-substituted Ba2(In2-xCrx)O5·(H2O)δ can be explained by the replacement of In by Cr. Consequently, an enhanced photocatalytic CO2 reduction activity was observed with increasing Cr substitution, compatible with the state-of-the-art high surface area TiO2 photocatalyst (P-25).

Computational insights into crystal plane dependence of thermal activity of anion (C and N)-substituted titania.

PubMed

V, Sai Phani Kumar; Arya, Rahul; Deshpande, Parag A

2017-11-29

Geometry optimizations of anion (C and N) doped anatase TiO 2 were carried out by using DFT+U calculations. Various anion vacancy sites were examined to study the synergistic effects of anion doping accompanied with anion vacancy formation on lattice oxygen activation. Two non-identical crystal planes (0 0 1) and (1 0 0) were chosen for C and N substitutions. Energetically favoured N-vacancy pairs were identified on TiO 2 surfaces. Substitution of N along with anion vacancies at various sites was energetically more favoured than that of C-doping in bulk TiO 2 while the energies were comparable for surface substitutions. Bond length distributions due to the formation of differential bonds were determined. Net oxygen activation and accompanying reversible oxygen exchange capacities were compared for TiO 2-2x C x and TiO 2-3x N 2x . Substitution of C in the surface exposed (1 0 0) plane of TiO 2 resulted in 47.6% and 23.8% of bond elongation and compression, respectively, resulting in 23.8% of net oxygen activation which was higher when compared to N substitution in the (1 0 0) plane of TiO 2 resulting in a net oxygen activation of 17%.

Pulsed laser induced heat transfer from a phthalocyanine-based thin film to a Bi, Al-substituted DyIG substrate: photothermal demagnetization observed by magnetic circular dichroism and numerical analysis.

PubMed

Karasawa, Masanobu; Ishii, Kazuyuki

2018-05-03

We have investigated the demagnetization of a ferrimagnetic substrate, Bi, Al-substituted dysprosium iron garnet (Bi0.8Dy2.2Fe4.3Al0.7O12), based on selective pulsed laser irradiation of a molecular thin film consisting of μ-oxo-bis[hydroxyl{2,9(or 10),16(or 17),23(or 24)-tetra-tert-butylphthalocyanato}silicon] ((SiPc)2) and poly(vinylidene fluoride), and succeeded in reproducing photothermal energy transfer from a molecular thin film to an inorganic magnetic substrate in a submicrometer-order and a submicrosecond time scale using numerical analysis. After the instant temperature rise due to nanosecond pulsed laser irradiation of the (SiPc)2-based film, followed by heat transfer from the film to the neighboring magnetic substrate, demagnetization of the magnetic substrate was spectroscopically monitored by the decrease in its magnetic circular dichroism (MCD) intensity. The MCD intensity decreased with increasing pulsed laser energy, which reflects the fact that the submicrometer-order region of the substrate was demagnetized as a result of temperature rise reaching high Curie temperature. This heat transfer phenomenon resulting in the demagnetization of the magnetic substrate was numerically analyzed in a submicrometer-order and a submicrosecond time scale using the finite difference method: the demagnetized regions were calculated to be the same order of magnitude as those experimentally evaluated. These results would provide a more detailed understanding of photothermal energy transfer in organic-inorganic hybrid materials, which would be useful for developing photofunctional materials.

Substitution in recreation choice behavior

Treesearch

George L. Peterson; Daniel J. Stynes; Donald H. Rosenthal; John F. Dwyer

1985-01-01

This review discusses concepts and theories of substitution in recreation choice. It brings together the literature of recreation research, psychology, geography, economics, and transportation. Parallel and complementary developments need integration into an improved theory of substitution. Recreation decision behavior is characterized as a nested or sequential choice...

Synthesis of enyne and aryl vinyl sulfoxides: functionalization via Pummerer rearrangement.

PubMed

Souza, Frederico B; Shamim, Anwar; Argomedo, Luiz M Z; Pimenta, Daniel C; Stefani, Hélio A

2015-11-01

An efficient methodology for the synthesis of aryl-substituted vinyl sulfoxides through direct substitution of aryl-substituted alkynyl grignard reagents on menthyl-p-toluenesulfinate followed by Suzuki-Miyaura cross-coupling reaction has been developed. It has also been described that the reaction of alkyl-substituted and cycloalkyl-substituted alkynyl grignard reagents with menthyl-p-toluenesulfinate led to two products, i.e., alkynyl sulfoxide derivatives, as a result of substitution, and enyne sulfoxide derivatives, which resulted from substitution followed by Michael type addition. It was possible to selectively synthesize the enyne sulfoxide derivatives by changing the concentration of the grignard reagent. These alkenyl sulfoxides were transformed into the corresponding [Formula: see text]-thio aldehydes in high yields via additive Pummerer rearrangement.

Biofortified β-carotene rice improves vitamin A intake and reduces the prevalence of inadequacy among women and young children in a simulated analysis in Bangladesh, Indonesia, and the Philippines1

PubMed Central

Angeles-Agdeppa, Imelda; Atmarita, Atmarita; Gironella, Glen M; Muslimatun, Siti; Carriquiry, Alicia

2016-01-01

Background: Vitamin A deficiency continues to be a major public health problem affecting developing countries where people eat mostly rice as a staple food. In Asia, rice provides up to 80% of the total daily energy intake. Objective: We used existing data sets from Bangladesh, Indonesia, and the Philippines, where dietary intakes have been quantified at the individual level to 1) determine the rice and vitamin A intake in nonpregnant, nonlactating women of reproductive age and in nonbreastfed children 1–3 y old and 2) simulate the amount of change that could be achieved in the prevalence of inadequate intake of vitamin A if rice biofortified with β-carotene were consumed instead of the rice consumed at present. Design: We considered a range of 4–20 parts per million (ppm) of β-carotene content and 10–70% substitution levels for the biofortified rice. Software was used to estimate usual rice and vitamin A intake for the simulation analyses. Results: In an analysis by country, the substitution of biofortified rice for white rice in the optimistic scenario (20 ppm and 70% substitution) decreased the prevalence of vitamin A inadequacy from baseline 78% in women and 71% in children in Bangladesh. In Indonesia and the Philippines, the prevalence of inadequacy fell by 55–60% in women and dropped by nearly 30% in children from baseline. Conclusions: The results of the simulation analysis were striking in that even low substitution levels and modest increases in the β-carotene of rice produced a meaningful decrease in the prevalence of inadequate intake of vitamin A. Increasing the substitution levels had a greater impact than increasing the β-carotene content by >12 ppm. PMID:27510534

Emerging drugs of abuse: current perspectives on substituted cathinones

PubMed Central

Paillet-Loilier, Magalie; Cesbron, Alexandre; Le Boisselier, Reynald; Bourgine, Joanna; Debruyne, Danièle

2014-01-01

Substituted cathinones are synthetic analogs of cathinone that can be considered as derivatives of phenethylamines with a beta-keto group on the side chain. They appeared in the recreational drug market in the mid-2000s and now represent a large class of new popular drugs of abuse. Initially considered as legal highs, their legal status is variable by country and is rapidly changing, with government institutions encouraging their control. Some cathinones (such as diethylpropion or pyrovalerone) have been used in a medical setting and bupropion is actually indicated for smoking cessation. Substituted cathinones are widely available from internet websites, retail shops, and street dealers. They can be sold under chemical, evocative or generic names, making their identification difficult. Fortunately, analytical methods have been developed in recent years to solve this problem. Available as powders, substituted cathinones are self-administered by snorting, oral injestion, or intravenous injection. They act as central nervous system stimulants by causing the release of catecholamines (dopamine, noradrenaline, and serotonin) and blocking their reuptake in the central and peripheral nervous system. They may also decrease dopamine and serotonin transporter function as nonselective substrates or potent blockers and may inhibit monoamine oxidase effects. Nevertheless, considerable differences have been found in the potencies of the different substituted cathinones in vitro. Desired effects reported by users include increased energy, empathy, and improved libido. Cardiovascular (tachycardia, hypertension) and psychiatric/neurological signs/symptoms (agitation, seizures, paranoia, and hallucinations) are the most common adverse effects reported. Severe toxicity signs compatible with excessive serotonin activity, such as hyperthermia, metabolic acidosis, and prolonged rhabdomyolysis, have also been observed. Reinforcing potential observed in animals predicts a high potential for addiction and abuse in users. In case of overdose, no specific antidote exists and no curative treatment has been approved by health authorities. Therefore, management of acute toxic effects is mainly extrapolated from experience with cocaine/amphetamines. PMID:24966713

QuEST: Qualifying Environmentally Sustainable Technologies, Volume 8

NASA Technical Reports Server (NTRS)

Ross, Kai T.

2013-01-01

Articles in this issue inlude: (1) TEERM Partners with GSDO Program, (2) Materials Management and Substitution Efforts, (3) Recycling and Pollution Control Efforts, and (4) Alternative Energy Efforts.

Change of Energy of the Cubic Subnanocluster of Iron Under Influence of Interstitial and Substitutional Atoms.

PubMed

Nedolya, Anatoliy V; Bondarenko, Natalya V

2016-12-01

Energy change of an iron face-centred cubic subnanocluster was evaluated using molecular mechanics method depending on the position of a carbon interstitial atom and substitutional atoms of nickel. Calculations of all possible positions of impurity atoms show that the energy change of the system are discrete and at certain positions of the atoms are close to continuous.In terms of energy, when all impurity atoms are on the same edge of an atomic cluster, their positions are more advantageous. The presence of nickel atoms on the edge of a cubic cluster resulted in decrease of potential barrier for a carbon atom and decrease in energy in the whole cluster. A similar drift of a carbon atom from central octahedral interstitial site to the surface in the direction <011> occurred under the influence of surface factors.Such configuration corresponds to decreasing symmetry and increasing the number of possible energy states of a subnanocluster, and it corresponds to the condition of spontaneous crystallization process in an isolated system.Taking into account accidental positions of the nickel atom in the iron cluster, such behaviour of the carbon atom can explain the mechanism of growth of a new phase and formation of new clusters in the presence of other kind of atoms because of surface influence.

Solvent and structural effects on the spectral shifts of 5-(substituted phenylazo)-3-cyano-6-hydroxy-1-(2-hydroxyethyl)-4-methyl-2-pyridones

NASA Astrophysics Data System (ADS)

Mirković, Jelena M.; Božić, Bojan Đ.; Mutavdžić, Dragosav R.; Ušćumlić, Gordana S.; Mijin, Dušan Ž.

2014-11-01

Spectral properties, solvatochromism and azo-hydrazone tautomerism of ten 5-(substituted phenylazo)-3-cyano-6-hydroxy-1-(2-hydroxyethyl)-4-methyl-2-pyridones in twenty-two solvents are investigated. For quantitative evaluation of the solvent effects on the UV-vis absorption maxima, the principles of the linear solvation energy relationships are used, i.e. models proposed by Kamlet-Taft and Catalán. Linear free energy relationships are applied to the UV-vis absorption spectra and correlation of absorption frequencies with Hammett substituent constants are performed. Furthermore, the influence of the electronic nature of the substituents on 1H and 13C NMR shifts is investigated by simple and extended Hammett equations, as well as by Swain-Lupton equation.

24 CFR 203.343 - Partial release, addition or substitution of security.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Partial release, addition or substitution of security. 203.343 Section 203.343 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING...

24 CFR 203.343 - Partial release, addition or substitution of security.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Partial release, addition or substitution of security. 203.343 Section 203.343 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING...

24 CFR 203.343 - Partial release, addition or substitution of security.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Partial release, addition or substitution of security. 203.343 Section 203.343 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING...

24 CFR 203.343 - Partial release, addition or substitution of security.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Partial release, addition or substitution of security. 203.343 Section 203.343 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING...

24 CFR 203.343 - Partial release, addition or substitution of security.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Partial release, addition or substitution of security. 203.343 Section 203.343 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING...

Silicon K-edge XANES spectra of silicate minerals

NASA Astrophysics Data System (ADS)

Li, Dien; Bancroft, G. M.; Fleet, M. E.; Feng, X. H.

1995-03-01

Silicon K-edge x-ray absorption near-edge structure (XANES) spectra of a selection of silicate and aluminosilicate minerals have been measured using synchrotron radiation (SR). The spectra are qualitatively interpreted based on MO calculation of the tetrahedral SiO{4/4-}cluster. The Si K-edge generally shifts to higher energy with increased polymerization of silicates by about 1.3 eV, but with considerable overlap for silicates of different polymerization types. The substitution of Al for Si shifts the Si K-edge to lower energy. The chemical shift of Si K-edge is also sensitive to cations in more distant atom shells; for example, the Si K-edge shifts to lower energy with the substitution of Al for Mg in octahedral sites. The shifts of the Si K-edge show weak correlation with average Si-O bond distance (dSi-O), Si-O bond valence (sSi-O) and distortion of SiO4 tetrahedra, due to the crystal structure complexity of silicate minerals and multiple factors effecting the x-ray absorption processes.

Ternary metal fluorides as high-energy cathodes with low cycling hysteresis

PubMed Central

Wang, Feng; Kim, Sung-Wook; Seo, Dong-Hwa; Kang, Kisuk; Wang, Liping; Su, Dong; Vajo, John J.; Wang, John; Graetz, Jason

2015-01-01

Transition metal fluorides are an appealing alternative to conventional intercalation compounds for use as cathodes in next-generation lithium batteries due to their extremely high capacity (3–4 times greater than the current state-of-the-art). However, issues related to reversibility, energy efficiency and kinetics prevent their practical application. Here we report on the synthesis, structural and electrochemical properties of ternary metal fluorides (M1yM21-yFx: M1, M2=Fe, Cu), which may overcome these issues. By substituting Cu into the Fe lattice, forming the solid–solution CuyFe1-yF2, reversible Cu and Fe redox reactions are achieved with surprisingly small hysteresis (<150 mV). This finding indicates that cation substitution may provide a new avenue for tailoring key electrochemical properties of conversion electrodes. Although the reversible capacity of Cu conversion fades rapidly, likely due to Cu+ dissolution, the low hysteresis and high energy suggest that a Cu-based fluoride cathode remains an intriguing candidate for rechargeable lithium batteries. PMID:25808876

Influence of functional groups on the C α-C β chain of L-phenylalanine and its derivatives

NASA Astrophysics Data System (ADS)

Ganesan, Aravindhan; Brunger, Michael; Wang, Feng

2010-07-01

L-phenylalanine ( L-phe) consists of three different functional groups, i.e., phenyl, carboxyl (-COOH) and amino (-NH 2), joining through the C α-C β bridge. Substitution of these groups produces 2-phenethylamine (PEA) and 3-phenylpropionic acid (PPA). Electronic structures of L-phe, PEA and PPA together with smaller "fragments" L-alanine and benzene were determined using density functional theory (DFT), from which core and valence shell ionization spectra were simulated. Comparison of the spectra reveals that core shell ionization energies clearly indicate that the carbon bridge is significantly affected by their functional group substitutions particularly at the C α site. In the valence space, quite unexpectedly, the frontier orbitals are concentrated on the benzene group although some energy splitting is observed. The orbitals which significantly affect the C α-C β carbon backbone are from the inner valence shell in the ionization energy region of 20-26 eV of the molecules.

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.

ERDA's Chemical Energy Storage Program

NASA Technical Reports Server (NTRS)

Swisher, J. H.; Kelley, J. H.

1977-01-01

The Chemical Energy Storage Program is described with emphasis on hydrogen storage. Storage techniques considered include pressurized hydrogen gas storage, cryogenic liquid hydrogen storage, storage in hydride compounds, and aromatic-alicyclic hydrogen storage. Some uses of energy storage are suggested. Information on hydrogen production and hydrogen use is also presented. Applications of hydrogen energy systems include storage of hydrogen for utilities load leveling, industrial marketing of hydrogen both as a chemical and as a fuel, natural gas supplementation, vehicular applications, and direct substitution for natural gas.

Influence of Cu substitution on the structural ordering, photocatalytic activity and photoluminescence emission of Ag3-2xCuxPO4 powders

NASA Astrophysics Data System (ADS)

Pereira, Wyllamanney da S.; Sczancoski, Júlio C.; Calderon, Yormary N. C.; Mastelaro, Valmor R.; Botelho, Gleice; Machado, Thales R.; Leite, Edson R.; Longo, Elson

2018-05-01

Materials presenting high photocatalytic performance and interesting photoluminescence emissions are promising candidates for photodegradation of organic pollutants discharged into natural waters as well as for development of new electro-optical devices, respectively. In this study, Ag3-2xCuxPO4 (x = 0.00, 0.01, 0.02, 0.04 and 0.08) powders were synthesized by the precipitation method. The long- and short-range structural ordering was affected when the copper (Cu) content was increased in the lattice, as identified by X-ray diffraction patterns, Fourier transform infrared spectroscopy and Raman spectroscopy, respectively. The field emission scanning electron microscope and transmission electron microscope revealed a particle system composed of irregular spherical-like microcrystals. The presence of Cu as well as its real amount in the samples were confirmed by means of X-ray photoelectron spectroscopy and inductively coupled plasma-atomic emission spectrometry, respectively. On increasing Cu level, a slight variation was noted on the photocatalytic activity of Ag3-2xCuxPO4 powders for degradation of rhodamine B under visible light irradiation. A photodegradation mechanism was proposed in details. The photoluminescence emissions were explained by electronic transitions involving intermediary energy levels in the band gap. The origin these energy levels was related to defects caused by the substitution of Ag by Cu in the crystalline structure.

FRAGS: estimation of coding sequence substitution rates from fragmentary data

PubMed Central

Swart, Estienne C; Hide, Winston A; Seoighe, Cathal

2004-01-01

Background Rates of substitution in protein-coding sequences can provide important insights into evolutionary processes that are of biomedical and theoretical interest. Increased availability of coding sequence data has enabled researchers to estimate more accurately the coding sequence divergence of pairs of organisms. However the use of different data sources, alignment protocols and methods to estimate substitution rates leads to widely varying estimates of key parameters that define the coding sequence divergence of orthologous genes. Although complete genome sequence data are not available for all organisms, fragmentary sequence data can provide accurate estimates of substitution rates provided that an appropriate and consistent methodology is used and that differences in the estimates obtainable from different data sources are taken into account. Results We have developed FRAGS, an application framework that uses existing, freely available software components to construct in-frame alignments and estimate coding substitution rates from fragmentary sequence data. Coding sequence substitution estimates for human and chimpanzee sequences, generated by FRAGS, reveal that methodological differences can give rise to significantly different estimates of important substitution parameters. The estimated substitution rates were also used to infer upper-bounds on the amount of sequencing error in the datasets that we have analysed. Conclusion We have developed a system that performs robust estimation of substitution rates for orthologous sequences from a pair of organisms. Our system can be used when fragmentary genomic or transcript data is available from one of the organisms and the other is a completely sequenced genome within the Ensembl database. As well as estimating substitution statistics our system enables the user to manage and query alignment and substitution data. PMID:15005802

Rapid hydrothermal flow synthesis and characterisation of carbonate- and silicate-substituted calcium phosphates

PubMed Central

Knowles, Jonathan C; Rehman, Ihtesham; Darr, Jawwad A

2013-01-01

A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising phase pure carbonated hydroxyapatite (CO3-HA) with ≈5 wt% substituted carbonate content (sample 7.5CO3-HA) and it was found that a further increase in urea concentration in solution resulted in biphasic mixtures of carbonate-substituted hydroxyapatite and calcium carbonate. Transmission electron microscopy images revealed that the particle size of hydroxyapatite decreased with increasing urea concentration. Energy-dispersive X-ray spectroscopy result revealed a calcium deficient apatite with Ca:P molar ratio of 1.45 (±0.04) in sample 7.5CO3-HA. For silicate-substituted hydroxyapatite (SiO4-HA) silicon acetate was used as a silicate ion source. It was observed that a substitution threshold of ∼1.1 wt% exists for synthesis of SiO4-HA in the continuous hydrothermal flow synthesis system, which could be due to the decreasing yields with progressive increase in silicon acetate concentration. All the as-precipitated powders (without any additional heat treatments) were analysed using techniques including Transmission electron microscopy, X-ray powder diffraction, Differential scanning calorimetry, Thermogravimetric analysis, Raman spectroscopy and Fourier transform infrared spectroscopy. PMID:22983020

Reducing Mg Acceptor Activation-Energy in Al0.83Ga0.17N Disorder Alloy Substituted by Nanoscale (AlN)5/(GaN)1 Superlattice Using MgGa δ-Doping: Mg Local-Structure Effect

NASA Astrophysics Data System (ADS)

Zhong, Hong-Xia; Shi, Jun-Jie; Zhang, Min; Jiang, Xin-He; Huang, Pu; Ding, Yi-Min

2014-10-01

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al0.83Ga0.17N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al0.83Ga0.17N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 1019 cm-3 can be obtained in (AlN)5/(GaN)1 SL by MgGa δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

Reducing Mg acceptor activation-energy in Al(0.83)Ga(0.17)N disorder alloy substituted by nanoscale (AlN)₅/(GaN)₁ superlattice using Mg(Ga) δ-doping: Mg local-structure effect.

PubMed

Zhong, Hong-xia; Shi, Jun-jie; Zhang, Min; Jiang, Xin-he; Huang, Pu; Ding, Yi-min

2014-10-23

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al(0.83)Ga(0.17)N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al(0.83)Ga(0.17)N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 10(19) cm(-3) can be obtained in (AlN)5/(GaN)1 SL by Mg(Ga) δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN.

Effect of metal in M 3(btc) 2 and M 2(dobdc) MOFs for O 2/N 2 separations: A combined density functional theory and experimental study

DOE PAGES

Parkes, Marie V.; Sava Gallis, Dorina F.; Greathouse, Jeffery A.; ...

2015-03-02

Computational screening of metal-organic framework (MOF) materials for selective oxygen adsorption from air could lead to new sorbents for the oxyfuel combustion process feedstock streams. A comprehensive study on the effect of MOF metal chemistry on gas binding energies in two common but structurally disparate metal-organic frameworks has been undertaken. Dispersion-corrected density functional theory methods were used to calculate the oxygen and nitrogen binding energies with each of fourteen metals, respectively, substituted into two MOF series, M 2(dobdc) and M 3(btc) 2. The accuracy of DFT methods was validated by comparing trends in binding energy with experimental gas sorption measurements.more » A periodic trend in oxygen binding energies was found, with greater oxygen binding energies for early transition-metal-substituted MOFs compared to late transition metal MOFs; this was independent of MOF structural type. The larger binding energies were associated with oxygen binding in a side-on configuration to the metal, with concomitant lengthening of the O-O bond. In contrast, nitrogen binding energies were similar across the transition metal series, regardless of both MOF structural type and metal identity. Altogether, these findings suggest that early transition metal MOFs are best suited to separating oxygen from nitrogen, and that the MOF structural type is less important than the metal identity.« less

Chemical substitution study on magnetism and superconductivity in Ce1-xSmxCoIn5

NASA Astrophysics Data System (ADS)

Jang, Sooyoung; White, B. D.; Yazici, D.; Wong, A. S.; Maple, M. B.

2015-03-01

We have investigated the system Ce1-xSmxCoIn5 (0 < x < 1) by means of x-ray diffraction, electrical resistivity, specific heat, and magnetization measurements. We observe a crossover from a coherent Kondo lattice exhibiting superconductivity to a single-ion impurity Kondo effect coexisting with magnetic order on the Sm-rich side of the phase diagram. The superconducting transition temperature, Tc, and Kondo lattice coherence temperature, Tcoh, are suppressed near x ~ 0.2 and x ~ 0.5, respectively, which is consistent with the effect of substitution with other rare-earth (RE) ions on CeCoIn5. After Tcoh is suppressed to 0 K, a single-ion impurity Kondo effect is observed for 0.5 < x <= 0.85. The compound SmCoIn5 exhibits three distinct magnetic phase transitions at roughly 8, 10, and 12 K, which are presumably associated with magnetic order; similar features are observed in the related compound SmIn3. These transition temperatures are gradually suppressed by Ce substitution and completely vanish near x ~ 0.2. We establish the phase diagram of the system Ce1-xSmxCoIn5 and compare our results with those obtained from chemical substitution studies of CeCoIn5 involving other RE ions. Research at UCSD was supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Material Science and Engineering under Grant No. DE-FG02-04-ER46105.

Role of the chemical substitution on the luminescence properties of solid solutions Ca{sub (1−x)}Cd{sub (x)}WO{sub 4} (0 ≤ x ≤1)

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

Taoufyq, A.; Laboratoire Matériaux et Environnement LME, Faculté des Sciences, Université Ibn Zohr, BP 8106, Cité Dakhla, Agadir; CEA, DEN, Département d'Etudes des Réacteurs, Service de Physique Expérimentale, Laboratoire Dosimétrie Capteurs Instrumentation, 13108 Saint-Paul-lez-Durance

2015-10-15

Highlights: • Luminescence can be modified by chemical substitution in solid solutions Ca{sub 1−x}Cd{sub x}WO{sub 4}. • The various emission spectra (charge transfer) were obtained under X-ray excitation. • Scheelite or wolframite solid solutions presented two types of emission spectra. • A luminescence component depended on cadmium substitution in each solid solution. • A component was only characteristic of oxyanion symmetry in each solid solution. - Abstract: We have investigated the chemical substitution effects on the luminescence properties under X-ray excitation of the solid solutions Ca{sub (1−x)}Cd{sub (x)}WO{sub 4} with 0 ≤ x ≤ 1. Two types of wide spectralmore » bands, associated with scheelite-type or wolframite-type solid solutions, have been observed at room temperature. We decomposed each spectral band into several spectral components characterized by energies and intensities varying with composition x. One Gaussian component was characterized by an energy decreasing regularly with the composition x, while the other Gaussian component was only related to the tetrahedral or octahedral configurations of tungstate groups WO{sub 4}{sup 2−} or WO{sub 6}{sup 6−}. The luminescence intensities exhibited minimum values in the composition range x < 0.5 corresponding to scheelite-type structures, then, they regularly increased for cadmium compositions x > 0.5 corresponding to wolframite-type structures.« less

How to regulate energy levels and hole mobility of spiro-type hole transport materials in perovskite solar cells.

PubMed

Chi, Wei-Jie; Sun, Ping-Ping; Li, Ze-Sheng

2016-10-21

Methoxyaniline-based organic small molecules with three-dimensional structure have been proven as the most promising hole conductor for state-of-the-art perovskite devices. A fundamental understanding of the electronic properties and hole transport behavior of spiro-CPDT analogues, which is dependent on the number and position of the -OCH 3 groups, is significant for their potential applications as hole transport materials of perovskite solar cells. Our results from density functional theory calculations indicate that meta-substitution is more beneficial to reduce the highest occupied molecular orbital (HOMO) levels of molecules compared with ortho- and para-substitution. Furthermore, the hole mobility can be improved by ortho-substitution or mixed ortho- and para-substitution. Most interestingly, it is found that the improvement in hole mobility is at the expense of raising the HOMO level of spiro-CPDT analogues. These results can be useful in the process of designing and synthesizing excellent hole transport materials with suitable HOMO levels and high hole mobility.

Substituent effect on photophysical properties of bi-1,3,4-oxadiazole derivatives in solution

NASA Astrophysics Data System (ADS)

Chen, Fangyi; Tian, Taiji; Zhao, Chengxiao; Bai, Binglian; Li, Min; Wang, Haitao

2016-04-01

A series of phenyl substituted bi-1,3,4-oxadiazole derivatives were designed and synthesized; the effect of substituent on the photophysical properties and molecular electronic structures was fully studied by the combination of experimental techniques and theoretical calculations. Compared to parent compound without any substituent (BOXD), fluoro-substituent shows little effect on the absorption and emission spectra, whilst a little larger spectral red-shift could be observed for methoxy-, nitro-substituted derivatives and thienyl-substituted bi-1,3,4-oxadiazole (TBOXD). These spectral changes can be well explained by theoretically calculated HOMO and LUMO energy level changes. All these molecules show high fluorescence quantum yield except for nitro-substituted derivative in dilute solutions. The quantum yield of BOXD changes with the concentration and exhibits a high value at the concentrated solution. This work revealed the influence of substituent on the photophysical properties of bi-1,3,4-oxadizaole derivatives in dilute solutions and provided guidance for designing molecules with potential application.

Calculation of Hammett Equation parameters for some N,N‧-bis (substituted-phenyl)-1,4-quinonediimines by density functional theory

NASA Astrophysics Data System (ADS)

Sein, Lawrence T.

2011-08-01

Hammett parameters σ' were determined from vertical ionization potentials, vertical electron affinities, adiabatic ionization potentials, adiabatic electron affinities, HOMO, and LUMO energies of a series of N, N' -bis (3',4'-substituted-phenyl)-1,4-quinonediimines computed at the B3LYP/6-311+G(2d,p) level on B3LYP/6-31G ∗ molecular geometries. These parameters were then least squares fit as a function of literature Hammett parameters. For N, N' -bis (4'-substituted-phenyl)-1,4-quinonediimines, the least squares fits demonstrated excellent linearity, with the square of Pearson's correlation coefficient ( r2) greater than 0.98 for all isomers. For N, N' -bis (3'-substituted-3'-aminophenyl)-1,4-quinonediimines, the least squares fits were less nearly linear, with r2 approximately 0.70 for all isomers when derived from calculated vertical ionization potentials, but those from calculated vertical electron affinities usually greater than 0.90.

Studies of the use of high-temperature nuclear heat from an HTGR for hydrogen production

NASA Technical Reports Server (NTRS)

Peterman, D. D.; Fontaine, R. W.; Quade, R. N.; Halvers, L. J.; Jahromi, A. M.

1975-01-01

The results of a study which surveyed various methods of hydrogen production using nuclear and fossil energy are presented. A description of these methods is provided, and efficiencies are calculated for each case. The process designs of systems that utilize the heat from a general atomic high temperature gas cooled reactor with a steam methane reformer and feed the reformer with substitute natural gas manufactured from coal, using reforming temperatures, are presented. The capital costs for these systems and the resultant hydrogen production price for these cases are discussed along with a research and development program.

A quantitative quantum chemical model of the Dewar-Knott color rule for cationic diarylmethanes

NASA Astrophysics Data System (ADS)

Olsen, Seth

2012-04-01

We document the quantitative manifestation of the Dewar-Knott color rule in a four-electron, three-orbital state-averaged complete active space self-consistent field (SA-CASSCF) model of a series of bridge-substituted cationic diarylmethanes. We show that the lowest excitation energies calculated using multireference perturbation theory based on the model are linearly correlated with the development of hole density in an orbital localized on the bridge, and the depletion of pair density in the same orbital. We quantitatively express the correlation in the form of a generalized Hammett equation.

Quality evaluation of carbonaceous industrial by-products and its effect on properties of autoclave aerated concrete

NASA Astrophysics Data System (ADS)

Fomina, E. V.; Lesovik, V. S.; Fomin, A. E.; Kozhukhova, N. I.; Lebedev, M. S.

2018-03-01

Argillite is a carbonaceous industrial by-product that is a potential source in environmentally friendly and source-saving construction industry. In this research, chemical and mineral composition as well as particle size distribution of argillite were studied and used to develop autoclave aerated concrete as partial substitute of quartz sand. Effect of the argillite as a mineral admixture in autoclave aerated concrete was investigated in terms of compressive and tensile strength, density, heat conductivity etc. The obtained results demonstrated an efficiency of argillite as an energy-saving material in autoclave construction composites.

Orthogonal sets of data windows constructed from trigonometric polynomials

NASA Technical Reports Server (NTRS)

Greenhall, C. A.

1989-01-01

Suboptimal, easily computable substitutes for the discrete prolate-spheroidal windows used by Thomson for spectral estimation are given. Trigonometric coefficients and energy leakages of the window polynomials are tabulated.

Prospective associations and population impact of sweet beverage intake and type 2 diabetes, and effects of substitutions with alternative beverages.

PubMed

O'Connor, Laura; Imamura, Fumiaki; Lentjes, Marleen A H; Khaw, Kay-Tee; Wareham, Nicholas J; Forouhi, Nita G

2015-07-01

This study aimed to evaluate the association of types of sugar-sweetened beverages (SSB) (soft drinks, sweetened-milk beverages, sweetened tea/coffee), artificially sweetened beverages (ASB) and fruit juice with incident type 2 diabetes and determine the effects of substituting non-SSB for SSB and the population-attributable fraction of type 2 diabetes due to total sweet beverages. Beverage consumption of 25,639 UK-resident adults without diabetes at baseline (1993-1997) in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study was assessed using 7-day food diaries. During 10.8 years of follow-up 847 incident type 2 diabetes cases were verified. In adjusted Cox regression analyses there were positive associations (HR [95% CI] per serving/day]) for soft drinks 1.21 (1.05, 1.39), sweetened-milk beverages 1.22 (1.05, 1.43) and ASB 1.22 (1.11, 1.33), but not for sweetened tea/coffee 0.98 (0.94, 1.02) or fruit juice 1.01 (0.88, 1.15). Further adjustment for adiposity attenuated the association of ASB, HR 1.06 (0.93, 1.20). There was a positive dose-response relationship with total sweet beverages: HR per 5% energy 1.18 (1.11, 1.26). Substituting ASB for any SSB did not reduce the incidence in analyses accounting for energy intake and adiposity. Substituting one serving/day of water or unsweetened tea/coffee for soft drinks and for sweetened-milk beverages reduced the incidence by 14%-25%. If sweet beverage consumers reduced intake to below 2% energy, 15% of incident diabetes might be prevented. The consumption of soft drinks, sweetened-milk beverages and energy from total sweet beverages was associated with higher type 2 diabetes risk independently of adiposity. Water or unsweetened tea/coffee appear to be suitable alternatives to SSB for diabetes prevention. These findings support the implementation of population-based interventions to reduce SSB consumption and increase the consumption of suitable alternatives.

Nuclear fuels policy. Report of the Atlantic Council's Nuclear Fuels Policy Working Group

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

Not Available

1976-01-01

This Policy Paper recommends the actions deemed necessary to assure that future U.S. and non-Communist countries' nuclear fuels supply will be adequate, considering the following: estimates of modest growth in overall energy demand, electrical energy demand, and nuclear electrical energy demand in the U.S. and abroad, predicated upon the continuing trends involving conservation of energy, increased use of electricity, and moderate economic growth (Chap. I); possibilities for the development and use of all domestic resources providing energy alternatives to imported oil and gas, consonant with current environmental, health, and safety concerns (Chap. II); assessment of the traditional energy sources whichmore » provide current alternatives to nuclear energy (Chap. II); evaluation of realistic expectations for additional future energy supplies from prospective technologies: enhanced recovery from traditional sources and development and use of oil shales and synthetic fuels from coal, fusion and solar energy (Chap. II); an accounting of established nuclear technology in use today, in particular the light water reactor, used for generating electricity (Chap. III); an estimate of future nuclear technology, in particular the prospective fast breeder (Chap. IV); current and projected nuclear fuel demand and supply in the U.S. and abroad (Chaps. V and VI); the constraints encountered today in meeting nuclear fuels demand (Chap. VII); and the major unresolved issues and options in nuclear fuels supply and use (Chap. VIII). The principal conclusions and recommendations (Chap. IX) are that the U.S. and other industrialized countries should strive for increased flexibility of primary energy fuel sources, and that a balanced energy strategy therefore depends on the secure supply of energy resources and the ability to substitute one form of fuel for another.« less

CALCULATED MOLECULAR STRUCTURES AND POTENTIAL ENERGY FUNCTIONS OF PAHS WITH METHYL CROWDING IN THE BAY REGION AND THEIR METABOLITES: COMPARISON TO EXPERIMENTAL STRUCTURES

EPA Science Inventory

Calculated molecular structures and potential energy functions ofP AHs with methyl crowding in the bay region and their metabolites: Comparison to experimental structures

PAHs with methyl group substitution near a bay region represent a class of chemicals associated with ...

CALCULATED MOLECULAR STRUCTURES AND POTENTIAL ENERGY FUNCTIONS OF PAHS WITH METHYL CROWDING IN THE BAY REGION AND THEIR METABOLITES: COMPARISON TO EXPERIMENTAL STRUCTURES

EPA Science Inventory

Abstract Title: Calculated molecular structures and potential energy functions of P AHs with methyl crowding in the bay region and their metabolites: Comparison to experimental structures.

Abstract:
PAHs with methyl group substitution near a bay region represent a cl...

Competitive/co-operative interactions in acid base sandwich: role of cation vs. substituents.

PubMed

Kalpana, Ayyavoo; Akilandeswari, Lakshminarayanan

2017-11-15

The cation-π interaction can be envisaged as a lewis acid base interaction, and it is in line with Pearson's acid base concept. The critical examination of interactions between the π-acids (alkali metal cations - Li + , Na + and alkaline earth metal cations Mg 2+ , Ca 2+ ) on one face and tripodal Cr(CO) 3 moiety on the other π face of substituted arenes demonstrates the role of cation and substitutents in manipulating the interactions between them. The interaction of the two π acids on both faces of arene is not expectedly additive, rather it shows either depreciation of interaction energy revealing the competition of acids toward the base or enhancement of interaction energy denoting a cooperative effect. Among the metal cations under study, Mg 2+ shows a cooperative gesture. Although the substituents play a meek role, they unfailingly exert their electronic effects and are amply documented by excellent correlation of various parameters with the Hammett constant σ m . The elusive switching of λ max from the UV to IR region on binding Mg 2+ with substituted arene-Cr(CO) 3 complex is a characteristic clue that TDDFT can help design the ionic sensors for Mg 2+ cations.

Effects of alloying and transmutation impurities on stability and mobility of helium in tungsten under a fusion environment

NASA Astrophysics Data System (ADS)

Wu, Xuebang; Kong, Xiang-Shan; You, Yu-Wei; Liu, C. S.; Fang, Q. F.; Chen, Jun-Ling; Luo, G.-N.; Wang, Zhiguang

2013-07-01

The behaviour of helium in metals is particularly significant in fusion research due to the He-induced degradation of materials. A small amount of impurities introduced either by intentional alloying or by transmutation reactions, will interact with He and lead the microstructure and mechanical properties of materials to change. In this paper, we present the results of first-principles calculations on the interactions of He with impurities and He diffusion around them in tungsten (W), including the interstitials Be, C, N, O, and substitutional solutes Re, Ta, Tc, Nb, V, Os, Ti, Si, Zr, Y and Sc. We find that the trapping radii of interstitial atoms on He are much larger than those of substitutional solutes. The binding energies between the substitutional impurities and He increase linearly with the relative charge densities at the He occupation site, indicating that He atoms easily aggregate at the low charge density site. The sequence of diffusion energy barriers of He around the possible alloying elements is Ti > V > Os > Ta > Re. The present results suggest that Ta might be chosen as a relatively suitable alloying element compared with other possible ones.

Climate Change Mitigation Challenge for Wood Utilization-The Case of Finland.

PubMed

Soimakallio, Sampo; Saikku, Laura; Valsta, Lauri; Pingoud, Kim

2016-05-17

The urgent need to mitigate climate change invokes both opportunities and challenges for forest biomass utilization. Fossil fuels can be substituted by using wood products in place of alternative materials and energy, but wood harvesting reduces forest carbon sink and processing of wood products requires material and energy inputs. We assessed the extended life cycle carbon emissions considering substitution impacts for various wood utilization scenarios over 100 years from 2010 onward for Finland. The scenarios were based on various but constant wood utilization structures reflecting current and anticipated mix of wood utilization activities. We applied stochastic simulation to deal with the uncertainty in a number of input variables required. According to our analysis, the wood utilization decrease net carbon emissions with a probability lower than 40% for each of the studied scenarios. Furthermore, large emission reductions were exceptionally unlikely. The uncertainty of the results were influenced clearly the most by the reduction in the forest carbon sink. There is a significant trade-off between avoiding emissions through fossil fuel substitution and reduction in forest carbon sink due to wood harvesting. This creates a major challenge for forest management practices and wood utilization activities in responding to ambitious climate change mitigation targets.

Boron Substituted Na 3 V 2 (P 1 -x B x O 4 ) 3 Cathode Materials with Enhanced Performance for Sodium-Ion Batteries

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

Hu, Pu; Wang, Xiaofang; Wang, Tianshi

The development of excellent performance of Na-ion batteries remains great challenge owing to the poor stability and sluggish kinetics of cathode materials. Herein, B substituted Na 3V 2P 3–xB xO 12 (0 ≤ x ≤ 1) as stable cathode materials for Na-ion battery is presented. A combined experimental and theoretical investigations on Na 3V 2P 3–xB xO 12 (0 ≤ x ≤ 1) are undertaken to reveal the evolution of crystal and electronic structures and Na storage properties associated with various concentration of B. X-ray diffraction results indicate that the crystal structure of Na 3V 2P 3–xB xO 12 (0more » ≤ x ≤ 1/3) consisted of rhombohedral Na 3V 2(PO 4) 3 with tiny shrinkage of crystal lattice. X-ray absorption spectra and the calculated crystal structures all suggest that the detailed local structural distortion of substituted materials originates from the slight reduction of V–O distances. Na 3V 2P 3-1/6B 1/6O 12 significantly enhances the structural stability and electrochemical performance, giving remarkable enhanced capacity of 100 and 70 mAh g -1 when the C-rate increases to 5 C and 10 C. Spin-polarized density functional theory (DFT) calculation reveals that, as compared with the pristine Na 3V 2(PO 4) 3, the superior electrochemical performance of the substituted materials can be attributed to the emergence of new boundary states near the band gap, lower Na + diffusion energy barriers, and higher structure stability.« less

A-Site Cation Substitutions in Strained Y-Doped BaZrO 3 Multilayer Films Leading to Fast Proton Transport Pathways

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

Aruta, Carmela; Han, Chu; Zhou, Si

Proton-conducting perovskite oxides form a class of solid electrolytes for novel electrochemical devices operating at moderate temperatures. Here, we use hard X-ray photoelectron spectroscopy, scanning transmission electron microscopy, and density functional theory calculations to investigate the structure and elucidate the origin of the fast proton transport properties of strained ultrathin films of Y-doped BaZrO 3 grown by pulsed lased deposition on NdGaO 3. Our study shows that our BaZr 0.8Y 0.2O 3 films incorporate a significant amount of Y dopants, and to a lesser extent also Zr ions, substituting for Ba 2+, and that these substitutional defects agglomerate forming columnarmore » regions crossing vertically from the surface to the interface the entire film. In conclusion, our calculations also show that, in regions rich in Y substitutions for both Zr and Ba, the proton transfer process involves nearly zero-energy barriers, indicating that A-site cation substitutions by Y lead to fast transport pathways and hence are responsible for the previously observed enhanced values of the proton conductivity of these perovskite oxide films.« less

Educating T-Shaped professionals to meet substitution challenges and developing business models for substitution and recycling

NASA Astrophysics Data System (ADS)

Arroyo, Ana; Mendibil Eguiluz, Javier; Sánchez Cupido, Laura

2018-03-01

One strategy to overcome the challenges related to critical raw materials (CRMs) is their substitution and recycling. However, the bright scientific idea, proof of concept or laboratory demonstration need to cross the valley of death in order to become stated as ‘a substitute’ instead of ‘a potential substitute’. Most PhD students and Post Docs specialize within a given thematic area; for example on specific materials or on substitution in a certain application. This specialization could limit the ability to generate innovations and profitable business models if there are not enough tools and skills to transform new knowledge and research results into an appealing value proposition towards customers and to a business opportunity for the current markets. The project proposes a framework for developing substitution and recycling related cross-sectorial skills and tools. These are applied for training business-related competences e.g. teamwork, management, communication, value proposition and business models design, especially within RTOs and industries. The proposed learning itinerary can radically improve the path from scientific proof of concept into innovation and lean start up or industrial market launch. The developed framework is tested by a pilot group having several topics within the areas of substitution and recycling of critical raw materials.

Snoek Relaxation in Fe-Cr Alloys and Interstitial-Substitutional Interaction

NASA Astrophysics Data System (ADS)

Golovin, I. S.; Blanter, M. S.; Schaller, R.

1997-03-01

The internal friction (IF) spectra of -Fe, Fe-Cr ferritic alloys and Cr have been investigated in a frequency range of 0.01 to 10 Hz. A Snoek-type relaxation was found in all the investigated C doped Fe-Cr alloys, starting from pure Fe and finishing with pure Cr. The temperature location of the Snoek peak (Tmax) in -Fe was found to be 315 K (1 Hz). The activation energy deduced from the T - f shift was 0.81 eV. Tmax in Cr was 433 K with an activation energy of 1.11 eV. The Snoek-type peaks in Fe-Cr alloys are much wider than in pure Fe or pure Cr. The temperature location of the peak versus chromium content curve exhibits a maximum in the vicinity of 35 wt% Cr (Tmax was 573 to 578 K, f 1.2 Hz and the activation energy was about 1.45 eV). It is important that Cr atoms in α-Fe have a more pronounced influence on the temperature location of the peak than Fe atoms have in chromium. A new model based on the atomic interactions is proposed to explain the influence of composition on Snoek peak location. The internal friction has been simulated by a Monte Carlo method, using C-C and C-substitutional atom (s) interaction energies. A model of long-range strain-induced (elastic) interaction supplemented by the chemical interaction in the two nearest coordination shells around an immobile substitutional atom was used for the C-s interaction. The interatomic interaction was supposed to affect IF by changing both the carbon atom arrangement (short-range order) and the energy of C atoms in octahedral interstices, and therefore the activation energy of IF. The peak temperatue calculated coincides well with the experimental ones if the value for the chemical interaction in the first coordination shell (Hchem) for C-Cr in Fe is - 0.15 eV and for C-Fe in Cr +0.15 eV. The difference in the influence of Cr in α-Fe and Fe in Cr is accounted for by a difference in the elastic and chemical interaction both between the carbon atoms and the substitutional atoms. The relaxation process in chromium Fe-based alloys is due to the carbon atom diffusion under stress between octahedral interstices of first and second coordination shells around the Cr atoms, and in Cr-based alloys, between second and third shells around the Fe atoms.

Chromium and Tantalum Site Substitution Patterns in Ni3Al (L1(sub 2))gamma(prime)- Precipitates

NASA Technical Reports Server (NTRS)

Booth-Morrison, Christopher; Mao, Zugang; Seidman, David N.; Noebe, Ronald D.

2008-01-01

The site substitution behavior of Cr and Ta in the Ni3Al (Ll2)-type gamma'-precipitates of a Ni-Al-Cr-Ta alloy is investigated by atom-probe tomography (APT) and first-principles calculations. Measurements of the gamma'-phase composition by APT suggest that Al, Cr, and Ta share the Al sublattice sites of the gamma'-precipitates. The calculated substitutional energies of the solute atoms at the Ni and Al sublattice sites indicate that Ta has a strong preference for the Al sites, while Cr has a weak Al site preference. Furthermore, Ta is shown to replace Cr at the Al sublattice sites of the gamma'-precipitates, altering the elemental phase partitioning behavior of the Ni-Al-Cr-Ta alloy.

Design of electrolyzer for carbon dioxide conversion to fuels and chemicals

NASA Astrophysics Data System (ADS)

Rosen, Jonathan S.

The stabilization of global atmospheric CO2 levels requires a transition towards a renewable energy based economy as well as methods for handling current CO2 output from fossil fuels. Challenges with renewable energy intermittency have thus far limited the use of these alternative energy sources to only a fraction of the current energy portfolio. To enable more widespread use of renewable energy systems, methods of large scale energy storage must be developed to store excess renewable energy when demand is low and allow for combined use of energy storage and renewable systems when demand is high. To date, no one technique has demonstrated energy storage methods on the gigawatt scale needed for integration with renewable sources; therefore the development of suitable energy storage technologies, such as CO2 electrolysis to fuels is needed. In this work, research efforts have focused on two major thrusts related to electrochemical methods of CO 2 conversion to fuels. The first thrust focuses on the synthesis and design of highly efficient anode and cathode catalysts with emphasis on understanding structure-property relationships. A second thrust focuses on the design of novel electrochemical devices for CO2 conversion and integration of synthesized materials into flow cell systems. On the anode side, the synthesis of highly active catalysts using abundant transition metals is crucial to reducing capital costs and enabling widespread use of electrochemical CO2 conversion devices. Highly active mesoporous Co3O4 and metal-substituted Co3O4 water oxidation catalysts were designed to investigate the role of the spinel structure on water oxidation activity. Further analysis of metal substituted samples reveal the importance of the octahedral sites in the spinel structure, which was later used to design an Mg-Co3O4 sample with improved water oxidation activity. The design of efficient cathode materials which can selectivity reduce CO2 to fuels and chemicals is critical to the widespread use of CO2 electrolysis. A nanoporous Ag material was synthesized through a dealloying technique able to operate with less than 0.5 V overpotential and high selectivity towards CO. CO is a valuable intermediate chemical which can used in Fischer-Tropsch or Gas-to-liquids technologies to produce liquids fuels. A detailed investigation of nanostructured Ag catalysts found stepped sites to be responsible for enhanced CO2 reduction activity due to improved stabilization of the COOH intermediate on the catalyst surface. In addition, an low-cost Zn dendrite electrocatalyst was developed using an electroplating technique. Low coordinated sites formed through electrodeposition demonstrated the suppression of hydrogen evolution while maintaining CO activity. The Zn dendrite electrocatalyst was further examined using a newly developed in situ X-ray absorption technique able to probe catalyst stability and crystalline structure under CO2 reduction operating conditions. A final hurdle in the realization of CO2 electrolysis technologies is the integration of catalysts into working flow cell devices. To address this issue and enable testing in a practical system, a highly efficient and robust CO2 electrolysis flow cell was designed including the scale up of the previous nanoporous Ag synthesis procedure. Using the modified porous Ag catalyst, currents in the Amp regime were demonstrated approaching rates needed for energy storage applications. Stability on the order of days was successfully demonstrated due to use of robust system components and conditions suitable for process scale up.

Criteria for solid recovered fuels as a substitute for fossil fuels--a review.

PubMed

Beckmann, Michael; Pohl, Martin; Bernhardt, Daniel; Gebauer, Kathrin

2012-04-01

The waste treatment, particularly the thermal treatment of waste has changed fundamentally in the last 20 years, i.e. from facilities solely dedicated to the thermal treatment of waste to facilities, which in addition to that ensure the safe plant operation and fulfill very ambitious criteria regarding emission reduction, resource recovery and energy efficiency as well. Therefore this contributes to the economic use of raw materials and due to the energy recovered from waste also to the energy provision. The development described had the consequence that waste and solid recovered fuels (SRF) has to be evaluated based on fuel criteria as well. Fossil fuels - coal, crude oil, natural gas etc. have been extensively investigated due to their application in plants for energy conversion and also due to their use in the primary industry. Thereby depending on the respective processes, criteria on fuel technical properties can be derived. The methods for engineering analysis of regular fuels (fossil fuels) can be transferred only partially to SRF. For this reason methods are being developed or adapted to current analytical methods for the characterization of SRF. In this paper the possibilities of the energetic utilization of SRF and the characterization of SRF before and during the energetic utilization will be discussed.

Refractory Research Group - U.S. DOE, Albany Research Center [Institution Profile

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

Bennett, James P.

2004-09-01

The refractory research group at the Albany Research Center (ARC) has a long history of conducting materials research within the U.S. Bureau of Mines, and more recently, within the U.S. Dept. of Energy. When under the U.S. Bureau of Mines, research was driven by national needs to develop substitute materials and to conserve raw materials. This mission was accomplished by improving refractory material properties and/or by recycling refractories using critical and strategic materials. Currently, as a U.S. Dept of Energy Fossil Energy field site, research is driven primarily by the need to assist DOE in meeting its vision to developmore » economically and environmentally viable technologies for the production of electricity from fossil fuels. Research at ARC impacts this vision by: • Providing information on the performance characteristics of materials being specified for the current generation of power systems; • Developing cost-effective, high performance materials for inclusion in the next generation of fossil power systems; and • Solving environmental emission and waste problems related to fossil energy systems. A brief history of past refractory research within the U.S. Bureau of Mines, the current refractory research at ARC, and the equipment and capabilities used to conduct refractory research at ARC will be discussed.« less

Configuring pnicogen rings in skutterudites for low phonon conductivity

NASA Astrophysics Data System (ADS)

Uher, Ctirad

2013-03-01

During the past dozen or so years, skutterudites have attracted much interest as prospective thermoelectric materials for power-generation applications in the temperature range 500K - 850K. Primary interest was focused on filled forms of skutterudites where loosely-bonded filler species resonantly scatter normal phonon modes of the structure thus reducing the lattice thermal conductivity. Using this approach with multiple fillers and incorporating various forms of nanoinclusions, impressive figures of merit ZT = 1.5-1.7 have been reported with n-type filled skutterudites. Since the dominant heat-carrying modes in skutterudites are associated with vibrations of the pnicogen rings, disruptions of the ring structure by substitutional alloying should be a similarly effective approach of lowering the lattice thermal conductivity. In this talk I discuss our recent work exploring alloying configurations of pnicogen rings that yield particularly low values of the thermal conductivity. We found that compensated double-substitution (replacing two Sb atoms with one atom each from the column IV and column VI elements) is a very effective approach. Our ab initio calculations, in combination with a cluster expansion, have allowed us to identify stable alloy configurations on the Sb rings. Subsequent molecular and lattice dynamics simulations on low energy configurations established the range of atomic displacement parameters and values of the thermal conductivity. Theoretical results turned out to be in good agreement with our experimental thermal conductivity values. Combining both approaches of compensated double-substitution and filling of structural cages should be an effective way of further improving the thermoelectric figure of merit of skutterudites. Work supported by the Center for Solar and Thermal Energy Conversion, and Enegy Frontier Research Center funded by the Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0000957

Modeled Dietary Impact of Pizza Reformulations in US Children and Adolescents.

PubMed

Masset, Gabriel; Mathias, Kevin C; Vlassopoulos, Antonis; Mölenberg, Famke; Lehmann, Undine; Gibney, Mike; Drewnowski, Adam

2016-01-01

Approximately 20% of US children and adolescents consume pizza on any given day; and pizza intake is associated with higher intakes of energy, sodium, and saturated fat. The reformulation of pizza products has yet to be evaluated as a viable option to improve diets of the US youth. This study modeled the effect on nutrient intakes of two potential pizza reformulation strategies based on the standards established by the Nestlé Nutritional Profiling System (NNPS). Dietary intakes were retrieved from the first 24hr-recall of the National Health and Nutrition Examination Survey (NHANES) 2011-12, for 2655 participants aged 4-19 years. The composition of pizzas in the NHANES food database (n = 69) were compared against the NNPS standards for energy, total fat, saturated fat, sodium, added sugars, and protein. In a reformulation scenario, the nutrient content of pizzas was adjusted to the NNPS standards if these were not met. In a substitution scenario, pizzas that did not meet the standards were replaced by the closest pizza, based on nutrient content, that met all of the NNPS standards. Pizzas consistent with all the NNPS standards (29% of all pizzas) were significantly lower in energy, saturated fat and sodium than pizzas that were not. Among pizza consumers, modeled intakes in the reformulation and substitution scenarios were lower in energy (-14 and -45kcal, respectively), saturated fat (-1.2 and -2.7g), and sodium (-143 and -153mg) compared to baseline. Potential industry wide reformulation of a single food category or intra-category food substitutions may positively impact dietary intakes of US children and adolescents. Further promotion and support of these complimentary strategies may facilitate the adoption and implementation of reformulation standards.

Modeled Dietary Impact of Pizza Reformulations in US Children and Adolescents

PubMed Central

Masset, Gabriel; Mathias, Kevin C.; Vlassopoulos, Antonis; Mölenberg, Famke; Lehmann, Undine; Gibney, Mike; Drewnowski, Adam

2016-01-01

Background and Objective Approximately 20% of US children and adolescents consume pizza on any given day; and pizza intake is associated with higher intakes of energy, sodium, and saturated fat. The reformulation of pizza products has yet to be evaluated as a viable option to improve diets of the US youth. This study modeled the effect on nutrient intakes of two potential pizza reformulation strategies based on the standards established by the Nestlé Nutritional Profiling System (NNPS). Methods Dietary intakes were retrieved from the first 24hr-recall of the National Health and Nutrition Examination Survey (NHANES) 2011–12, for 2655 participants aged 4–19 years. The composition of pizzas in the NHANES food database (n = 69) were compared against the NNPS standards for energy, total fat, saturated fat, sodium, added sugars, and protein. In a reformulation scenario, the nutrient content of pizzas was adjusted to the NNPS standards if these were not met. In a substitution scenario, pizzas that did not meet the standards were replaced by the closest pizza, based on nutrient content, that met all of the NNPS standards. Results Pizzas consistent with all the NNPS standards (29% of all pizzas) were significantly lower in energy, saturated fat and sodium than pizzas that were not. Among pizza consumers, modeled intakes in the reformulation and substitution scenarios were lower in energy (-14 and -45kcal, respectively), saturated fat (-1.2 and -2.7g), and sodium (-143 and -153mg) compared to baseline. Conclusions Potential industry wide reformulation of a single food category or intra-category food substitutions may positively impact dietary intakes of US children and adolescents. Further promotion and support of these complimentary strategies may facilitate the adoption and implementation of reformulation standards. PMID:27706221

Energy content, sensory properties, and microbiological shelf life of German bologna-type sausages produced with citrate or phosphate and with inulin as fat replacer.

PubMed

Nowak, B; von Mueffling, T; Grotheer, J; Klein, G; Watkinson, B-M

2007-11-01

The aim of this study was to determine the feasibility of reducing energy content (9% to 48%) in bologna-type sausages by replacing fat with inulin and to study the effects of substituting citrate for phosphate in the traditional sausage formula. German-type mortadella was produced, and fat was replaced with increasing amounts of inulin as a frozen gel to yield 3%, 6%, 9%, and 12% inulin in the final product. In another part of the study, citrate was substituted for the phosphate in the recipe. All sausages produced were sliced, packaged under a modified atmosphere (70% N(2), 30% CO(2)), and stored for 23 d at +7 degrees C. Sausage quality was determined by chemical and instrumental texture profile analyses, color measurement, sensory evaluation, and microbiological testing. Replacing fat with inulin led to significant energy content reductions of up to 47.5% (with 12% inulin). However, the sensory properties of these sausages were also different from those of the control mortadella: fracturability fell, hardness and adhesiveness rose, and color became darker. In general, the substitution of citrate for phosphate significantly reduced the negative effects of inulin. There were no significant differences in microbiological stability between different inulin batches but there were significant differences between phosphate and citrate batches. Overall, the energy content of bologna-type sausages produced with citrate and with up to 6% inulin as a fat replacer was 22% lower than that of the control sausages. Furthermore, the sensory attributes (texture, color) of these 6% inulin-citrate sausages were comparable to the control sausages, and the sausages were microbiologically stable for 23 d of storage.

Potential nutritional and economic effects of replacing juice with fruit in the diets of children in the United States

PubMed Central

Monsivais, Pablo; Rehm, Colin D

2013-01-01

Context Dietary guidance for children emphasizes fruit over fruit juices but little is known about the potential nutritional and economic impact of substituting fruit for juice. Objective To estimate the nutritional and economic effects of substituting whole fruit for juice in the diets of children in the US. Design Secondary analyses using the 2001-2004 National Health and Nutrition Examination Survey (NHANES) and a national food price database. Energy, nutrient intakes and diet cost were estimated before and after fruit juices were completely replaced with fruit in three models that emphasized fruits that were fresh, low-cost, and widely-consumed and a fourth model that partially replaced juice with fruit, capping juice at recommended levels. Setting A nationwide, representative sample of children in the US. Participants 7,023 children ages 3-18. Main Outcome Measures Difference in energy, nutrient intakes and diet cost between observed and modeled diets. Results For children who consumed juice, replacement of all juice servings with fresh, whole fruit led to a projected reduction in dietary energy of 233 kJ/day (−2.6% [95% CI −5.1, −0.1%]), an increase in fiber of 4.3 grams/day (+31.1% [95% CI 26.4, 35.9%]) and an increase in diet cost of $0.54/day (+13.3% [95% CI 8.8, 17.8%]). Conclusions Substitution of juice with fresh fruit has the potential to reduce energy intake and improve the adequacy of fiber intake in children’s diets. This would likely increase costs for schools, childcare providers and families. Cost impacts could be minimized by selecting processed fruits but fewer nutritional gains would be achieved. PMID:22566547

Biodiesel

DOT National Transportation Integrated Search

1995-01-01

This is one in a fact sheet series, "BioFacts: Fueling a Stronger Economy," : produced by the National Renewable Energy Laboratory on biofuels. This fact : sheet briefly discusses biodiesel, substitute for or an additive to diesel fuel : that is deri...

Isomorphous Substitution of Rare-Earth Elements in Lacunary Apatite Pb8Na2(PO4)6.

PubMed

Get'man, Evgeni I; Loboda, Stanislav N; Ignatov, Alexey V; Prisedsky, Vadim V; Abdul Jabar, Mohammed A B; Ardanova, Lyudmyla I

2016-03-07

The substitution of rare-earth elements (REEs) for Pb in the lacunary apatite Pb8Na2(PO4)6 with void structural channels was studied by means of powder X-ray diffraction (including the Rietveld refinement), scanning electron microscopy, energy-dispersive X-ray microanalysis, and IR spectroscopy and also measurements of the electrical conductivity. The substitution limits (xmax in Pb8-xLnxNa2(PO4)6Ox/2) at 800 °C were found to decrease with the atomic number of the REE from 1.40 for La to 0.12 for Yb with a rapid drop from light to heavy lanthanides (between Gd and Tb). The REE atoms substitute for Pb predominantly at Pb2 sites of the apatite structure according to the scheme 2Pb(2+) + □ → 2Ln(3+) + O(2-), where □ is a vacancy in the structural channel. The substitution in lacunary apatite produces quite different changes in the structural parameters compared with broadly studied alkaline-earth hydroxyapatites. In spite of the much lower ionic radii of REE than that of Pb(2+), the mean distances ⟨Pb1-O⟩ somewhat increase, whereas the distances ⟨Pb2-Pb2⟩ and ⟨Pb2-O4⟩ do not change considerably with the degree of substitution. This implies control of the substitution by not only spatial and charge accommodation of REE ions but also the availability of a stereochemically active 6s(2) electron pair on Pb(2+). The high-temperature electrical conductivity shows dependence on the degree of substitution with a minimum at x = 0.2 indicative of a possible change of the type of conductivity.

Phase Composition and Disorder in La2(Sn,Ti)2O7 Ceramics: New Insights from NMR Crystallography.

PubMed

Fernandes, Arantxa; McKay, David; Sneddon, Scott; Dawson, Daniel M; Lawson, Sebastian; Veazey, Richard; Whittle, Karl R; Ashbrook, Sharon E

2016-09-15

An NMR crystallographic approach, involving the combination of 119 Sn NMR spectroscopy, XRD, and DFT calculations, is demonstrated for the characterization of La 2 Sn 2- x Ti x O 7 ceramics. A phase change from pyrochlore (La 2 Sn 2 O 7 ) to a layered perovskite phase (La 2 Ti 2 O 7 ) is predicted (by radius ratio rules) to occur when x ≈ 0.95. However, the sensitivity of NMR spectroscopy to the local environment is able to reveal a significant two-phase region is present, extending from x = 1.8 to ∼0.2, with limited solid solution at the two extremes, in broad agreement with powder XRD measurements. DFT calculations reveal that there is preferential site substitution of Sn in La 2 Ti 2 O 7 , with calculated shifts for Sn substitution onto Ti1 and Ti2 sites (in the "bulk" perovskite layers) in better agreement with experiment than those for Ti3 and Ti4 ("edge" sites). Substitution onto these two sites also produces structural models with lower relative enthalpy. As the Sn content decreases, there is a further preference for substitution onto Sn2. In contrast, the relative intensities of the spectral resonances suggest that Ti substitution into the pyrochlore phase is random, although only a limited solid solution is observed (up to ∼7% Ti). DFT calculations predict very similar 119 Sn shifts for Sn substitution into the two proposed models of La 2 Ti 2 O 7 (monoclinic ( P 2 1 ) and orthorhombic ( Pna 2 1 )), indicating it is not possible to distinguish between them. However, the relative energy of the Sn-substituted orthorhombic phase was higher than that of substituted monoclinic cells, suggesting that the latter is the more likely structure.

Substituent and Solvent Effects on Excited State Charge Transfer Behavior of Highly Fluorescent Dyes Containing Thiophenylimidazole-Based Aldehydes

NASA Technical Reports Server (NTRS)

Santos, Javier; Bu, Xiu R.; Mintz, Eric A.

2001-01-01

The excited state charge transfer for a series of highly fluorescent dyes containing thiophenylimidazole moiety was investigated. These systems follow the Twisted Intramolecular Charge Transfer (TICT) model. Dual fluorescence was observed for each substituted dye. X-ray structures analysis reveals a twisted ground state geometry for the donor substituted aryl on the 4 and 5 position at the imidazole ring. The excited state charge transfer was modeled by a linear solvation energy relationship using Taft's pi and Dimroth's E(sub T)(30) as solvent parameters. There is linear relation between the energy of the fluorescence transition and solvent polarity. The degree of stabilization of the excited state charge transfer was found to be consistent with the intramolecular molecular charge transfer. Excited dipole moment was studied by utilizing the solvatochromic shift method.

Substitution Effects and Linear Free Energy Relationships During Reduction of 4- Benzoyl-n-(4-substituted Benzyl)pyridinium Cations

NASA Technical Reports Server (NTRS)

Leventis, Nicholas; Zhang, Guo-Hui; Rawashdeh, Abdel-Monem M.; Sotiriou-Leventis, Chariklia; Gray, Hugh R. (Technical Monitor)

2003-01-01

In analogy to 4-(para-substituted benzoyl)-N-methylpyridinium cations (1-X's), the title species (2-X's, -X = -OCH3, -CH3, -H, -Br, -COCH3, -NO2) undergo two reversible, well-separated (E(sub 1/2) greater than or equal to 650 mV) one-electron reductions. The effect of substitution on the reduction potentials of 2-X's is much weaker than the effect of the same substituents on 1-X's: the Hammett rho-values are 0.80 and 0.93 for the 1st- and 2nd-e reduction of 2-X's vs. 2.3 and 3.3 for the same reductions of 1-X's, respectively. Importantly, the nitro group of 2-NO2 undergoes reduction before the 2nd-e reduction of the 4-benzoylpyridinium system. These results suggest that the redox potentials of the 4-benzoylpyridinium system can be course-tuned via p-benzoyl substitution and fine-tuned via para-benzyl substitution. Introducing the recently derived substituent constant of the -NO2(sup)- group (sigma para-NO2(sup)- = -0.97) yields an excellent correlation for the 3rd-e reduction of 2- NO2 (corresponding to the reduction of the carbonyl group) with the 2nd-e reduction of the other 2-X's, and confirms the electron donating properties of -NO2(sup)-.

Contribution of Golden Apple Snail Flour to Enhance Omega- 3 and Omega-6 Fatty Acids Contents in Weaning Food

NASA Astrophysics Data System (ADS)

Marsyha, D. D.; Wijayanti, H. S.; Nuryanto; Anjani, G.

2018-02-01

The case of undernourished children in Grobogan District (15.3%) is caused by children nutrients intake less than the Recommendation Dietary Allowance (RDA). To enhance children nutrients intake, be required formulation of weaning food using high-nutrient local food such as golden apple snail (Pomacea canaliculata). Golden apple snail flour contains high contents of zinc, iron, omega-3 and omega-6 fatty acids. This study aims to analyze the effect of golden apple snail flour substitution on nutrients content and organoleptic properties of weaning food (baby porridge). This is an experimental research by substitution of golden apple snail flour in the making of weaning food with four treatments of substitution (0%, 5%, 10%, 15%). Substitution of golden apple snails flour could affect the nutrient content levels of fat, zinc, iron (p=0.0001), carbohydrate (p=0.011), water (p=0.003), ash (p=0.001), omega-3 and omega-6 fatty acids. Whereas, it could not affect the content of energy (p=0.678), protein (p=0.129) and fiber (p=0.482). Furthermore, the substitution could affect the organoleptic properties include color, texture and taste (p=0.0001) while not for the aroma (p=0.798). Based on nutrient content analysis, substitution of golden apple snail flour could enhance the zinc, iron, omega-3 and omega-6 fatty acids contents of weaning food.

Electronic Structure of p- and n-Type Doping Impurities in Cubic Gallium Nitride

NASA Astrophysics Data System (ADS)

Pentaleri, E. A.; Gubanov, V. A.; Fong, C. Y.; Klein, B. M.

1996-03-01

LMTO-TB calculations were performed to investigate the electronic structure of C, Be, Mg, Si, Zn, and Cd substitutional impurities in cubic GaN (c-GaN). The calculations used 128-site supercells consisting of 64-atoms. Empty spheres of two types occupied the remaining sites. Semi-core Ga 3d states were treated explicitly as valence states. Both amphoteric substitutions were considered for C and Si impurities, while only cation-site substitutions were considered for Be, Mg, Zn, and Cd. All metal impurities formed partially occupied impurity states at the VB edge, which may result in p-type conductivity. C and Si impurities substituted at anion sites form sharp resonances in the gap, and are inactive in creating either p- or n-type carriers. Likewise, cation-site C substitutions introduce to the middle of the band gap strongly localized states that are inactive in carrier formation. Cation-site Si substitutions form an impurity sub-band at the CB edge, leading to n-type conductivity. The DOS at the Fermi level for each impurity-doped c-GaN crystal is used to estimate the most effective p-type doping impurities. The wave-function composition, space, and energy localization is analyzed for different impurities via projections onto the orbital basis and atomic coordinational spheres, and by examining calculated charge-density distributions.

Fast synthesis of La-substituted apatite by the dry mechanochemical method and analysis of its structure

NASA Astrophysics Data System (ADS)

Bulina, Natalia V.; Chaikina, Marina V.; Prosanov, Igor Yu.; Dudina, Dina V.; Solovyov, Leonid A.

2017-08-01

Compared to pure apatite, La-substituted apatites have improved thermal, mechanical and biological characteristics. In this article, a fast synthesis of La-substituted apatites by a dry mechanochemical method is presented. Structural studies by X-ray diffraction and Fourier transform infrared spectroscopy indicated the formation of a single-phase nanosized product after 30 min of high-energy ball milling of the reaction mixtures. The dry mechanochemical method is technologically attractive for the preparation of La-substituted apatites, as it allows reducing the processing time down to half an hour and does not require prolonged high-temperature annealing normally used in the synthesis practice of the substituted apatite. As the mechanochemically synthesized samples are nanosized, it is difficult to determine the details of their crystal structure by the Rietveld refinement method. Therefore, a series of the mechanochemically synthesized samples with different concentrations of lanthanum were annealed at 1000°C for 5 h. It was found that the annealed powders are microcrystalline La-substituted apatites Ca10-xLax(PO4)6Ox(OH)2-x, where 0 ≤ x ≤2. In their structure, the Ca2+ ions are replaced by the La3+ ions localized near the Ca2 sites, and the OH- groups are replaced by the O2- ions in the hexagonal channels.

Spectroscopic and DFT Study of RhIII Chloro Complex Transformation in Alkaline Solutions.

PubMed

Vasilchenko, Danila B; Berdyugin, Semen N; Korenev, Sergey V; O'Kennedy, Sean; Gerber, Wilhelmus J

2017-09-05

The hydrolysis of [RhCl 6 ] 3- in NaOH-water solutions was studied by spectrophotometric methods. The reaction proceeds via successive substitution of chloride with hydroxide to quantitatively form [Rh(OH) 6 ] 3- . Ligand substitution kinetics was studied in an aqueous 0.434-1.085 M NaOH matrix in the temperature range 5.5-15.3 °C. Transformation of [RhCl 6 ] 3- into [RhCl 5 (OH)] 3- was found to be the rate-determining step with activation parameters of ΔH † = 105 ± 4 kJ mol -1 and ΔS † = 59 ± 10 J K -1 mol -1 . The coordinated hydroxo ligand(s) induces rapid ligand substitution to form [Rh(OH) 6 ] 3- . By simulating ligand substitution as a dissociative mechanism, using density functional theory (DFT), we can now explain the relatively fast and slow kinetics of chloride substitution in basic and acidic matrices, respectively. Moreover, the DFT calculated activation energies corroborated experimental data that the kinetic stereochemical sequence of [RhCl 6 ] 3- hydrolysis in an acidic solution proceeds as [RhCl 6 ] 3- → [RhCl 5 (H 2 O)] 2- → cis-[RhCl 4 (H 2 O) 2 ] - . However, DFT calculations predict in a basic solution the trans route of substitution [RhCl 6 ] 3- → [RhCl 5 (OH)] 3- → trans-[RhCl 4 (OH) 2 ] 3- is kinetically favored.

Investigation of the Redox Chemistry of Anthraquinone Derivatives Using Density Functional Theory

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

Bachman, Jonathan E.; Curtiss, Larry A.; Assary, Rajeev S.

2014-09-25

Application of density functional calculations to compute electrochemical properties such as redox windows, effect of substitution by electron donating and electron withdrawing groups on redox windows, and solvation free energies for ~50 anthraquinone (AQ) derivatives are presented because of their potential as anolytes in all-organic redox flow batteries. Computations suggest that lithium ions can increase (by ~0.4 V) the reduction potential of anthraquinone due to the lithium ion pairing by forming a Lewis base-Lewis acid complex. To design new redox active species, the substitution by electron donating groups are essential to improve the reduction window of AQ with adequate oxidativemore » stability. For instance, a complete methylation of AQ can improve its reduction window by ~0.4 V. The quantum chemical studies of the ~50 AQ derivatives are used to derive a relationship that connects the computed LUMO energy and the reduction potential that can be applied as a descriptor for screening thousands of AQ derivatives. Our computations also suggest that incorporating oxy-methyl dioxolane substituents in the AQ framework can increase its interaction with non-aqueous solvent and improve its solubility. Thermochemical calculations for likely bond breaking decomposition reactions of un-substituted AQ anions suggest that the dianions are relatively stable in the solution. These studies provide ideal platform to perform further combined experimental and theoretical studies to understand the electrochemical reversibility and solubility of new quinone molecules as energy storage materials.« less

Control of exciton confinement in quantum dot-organic complexes through energetic alignment of interfacial orbitals.

PubMed

Frederick, Matthew T; Amin, Victor A; Swenson, Nathaniel K; Ho, Andrew Y; Weiss, Emily A

2013-01-09

This paper describes a method to control the quantum confinement, and therefore the energy, of excitonic holes in CdSe QDs through adsorption of the hole-delocalizing ligand phenyldithiocarbamate, PTC, and para substitutions of the phenyl ring of this ligand with electron-donating or -withdrawing groups. These substitutions control hole delocalization in the QDs through the energetic alignment of the highest occupied orbitals of PTC with the highest density-of-states region of the CdSe valence band, to which PTC couples selectively.

Rotational characterization of methyl methacrylate: Internal dynamics and structure determination

NASA Astrophysics Data System (ADS)

Herbers, Sven; Wachsmuth, Dennis; Obenchain, Daniel A.; Grabow, Jens-Uwe

2018-01-01

Rotational constants, Watson's S centrifugal distortion coefficients, and internal rotation parameters of the two most stable conformers of methyl methacrylate were retrieved from the microwave spectrum. Splittings of rotational energy levels were caused by two non equivalent methyl tops. Constraining the centrifugal distortion coefficients and internal rotation parameters to the values of the main isotopologues, the rotational constants of all single substituted 13C and 18O isotopologues were determined. From these rotational constants the substitution structures and semi-empirical zero point structures of both conformers were precisely determined.

Effect of solute atoms on dislocation motion in Mg: An electronic structure perspective

PubMed Central

Tsuru, T.; Chrzan, D. C.

2015-01-01

Solution strengthening is a well-known approach to tailoring the mechanical properties of structural alloys. Ultimately, the properties of the dislocation/solute interaction are rooted in the electronic structure of the alloy. Accordingly, we compute the electronic structure associated with, and the energy barriers to dislocation cross-slip. The energy barriers so obtained can be used in the development of multiscale models for dislocation mediated plasticity. The computed electronic structure can be used to identify substitutional solutes likely to interact strongly with the dislocation. Using the example of a-type screw dislocations in Mg, we compute accurately the Peierls barrier to prismatic plane slip and argue that Y, Ca, Ti, and Zr should interact strongly with the studied dislocation, and thereby decrease the dislocation slip anisotropy in the alloy. PMID:25740411

Stricture of the afferent isoperistaltic tubular segment: a late and rare cause of bilateral dilation of the upper urinary tract after ileal bladder substitution.

PubMed

Kiss, Bernhard; Schöndorf, Daniel; Studer, Urs E; Roth, Beat

2013-08-01

To evaluate the etiology and treatment of bilateral hydronephrosis not responding to bladder substitute drainage after ileal bladder substitution using an afferent isoperistaltic tubular segment. A retrospective analysis was performed of a consecutive series of 739 patients who had undergone bladder substitution from April 1985 to August 2012. Of the 739 ileal bladder substitute patients, 10 (1.4%) developed bilateral hydronephrosis unresponsive to complete bladder substitute drainage. The etiology was stenosis of the afferent isoperistaltic tubular segment. The median interval to presentation was 131 months (range 45-192). The incidence of afferent tubular segment stenosis was significantly higher in the 61 ileal bladder substitute patients with recurrent urinary tract infection (9 [15%]) than in the 678 without recurrent urinary tract infection (1 [0.15%]; P <.001). Urine cultures revealed mixed infections (34%), Escherichia coli (18%), Staphylococcus aureus (13%), enterococci (11%), Candida (8%), Klebsiella (8%), and others (8%). Seven patients underwent 10 endourologic interventions, only 1 of which was successful (10%). After failed endourologic treatment, 7 open surgical revisions with resection of the stricture were performed, with all 7 (100%) successful. Bilateral dilation of the upper urinary tract after ileal orthotopic bladder substitution unresponsive to complete bladder substitute drainage is likely to be caused by stenosis of the afferent isoperistaltic tubular segment. The stenosis occurs almost exclusively in patients with long-lasting, recurrent urinary tract infection and can develop many years after the ileal bladder substitution. Minimally invasive endourologic treatment is usually unsuccessful; however, open surgical revision offers excellent results. Copyright © 2013 Elsevier Inc. All rights reserved.

Biogas upgrading and utilization: Current status and perspectives.

PubMed

Angelidaki, Irini; Treu, Laura; Tsapekos, Panagiotis; Luo, Gang; Campanaro, Stefano; Wenzel, Henrik; Kougias, Panagiotis G

Biogas production is an established sustainable process for simultaneous generation of renewable energy and treatment of organic wastes. The increasing interest of utilizing biogas as substitute to natural gas or its exploitation as transport fuel opened new avenues in the development of biogas upgrading techniques. The present work is a critical review that summarizes state-of-the-art technologies for biogas upgrading and enhancement with particular attention to the emerging biological methanation processes. The review includes comprehensive description of the main principles of various biogas upgrading methodologies, scientific and technical outcomes related to their biomethanation efficiency, challenges that have to be addressed for further development and incentives and feasibility of the upgrading concepts. Copyright © 2018 Elsevier Inc. All rights reserved.

Quantum and Statistical Mechanics Applied to Singlet Carbenes, Pericyclic Reactions, and Condensed Phase Phenomena

NASA Astrophysics Data System (ADS)

Evanseck, Jeffrey Donald

The completed research covers a broad range of theoretical applications in organic chemistry. It is divided into three chapters which covers the chemistry of singlet carbenes (Chapter 1), substituent effects in pericyclic rearrangements (Chapter 2), and the effects of solvent on the reactivity of organic reactions (Chapter 3). The selectivity between 1,2- and 1,4-intramolecular additions to restricted diene systems has been investigated. A decrease in activation energy for the intramolecular cycloaddition is noted for systems which approach the idealized geometry found with intermolecular addition of carbenes to olefins. Direct substitution at the carbene site dramatically effects the predicted activation barriers for 1,2-hydrogen shifts. An excellent correlation between the activation energy and a substituents sigma_sp {rm R}{rm o} parameters has been demonstrated. The long standing problem of orbital alignment influences on the selectivity of 1,2-hydrogen arrangements shows significant geometric distortions, yet has little influence on the rates of singlet alkylcarbene rearrangements. The exo-selectivities observed for 1,2-shifts in rigid systems are explained by torsional and steric interactions which develop in the transition structures. Substituent effects on pericyclic reactions have been computed for several conrotatory and disrotatory electrocyclizations. The six-electron disrotatory electrocyclization of 1-substituted hexatrienes displays a strong electronic component in determining stereoselectivity, despite incredible steric interference. The eight-electron conrotatory electrocyclization transition structure of 1-substituted octatetraene has an unusual helical transition structure which does not differentiate between substituent position. The effects of solvents on the acidity differences between E and Z esters has supplemented earlier ab initio quantum mechanical results on the enhanced acidity of Meldrum's acid. Monte Carlo simulations predict a preferential stabilization of the E isomer in both acetonitrile and aqueous solutions. The rates of intramolecular Diels-Alder reactions are compared to recent experimental work and predictions of different solvent systems are made.

Synthesis of new visible light active photocatalysts of Ba(In(1/3)Pb(1/3)M'(1/3))O3 (M' = Nb, Ta): a band gap engineering strategy based on electronegativity of a metal component.

PubMed

Hur, Su Gil; Kim, Tae Woo; Hwang, Seong-Ju; Park, Hyunwoong; Choi, Wonyong; Kim, Sung Jin; Kim, Sun Jin; Choy, Jin-Ho

2005-08-11

We have synthesized new, efficient, visible light active photocatalysts through the incorporation of highly electronegative non-transition metal Pb or Sn ions into the perovskite lattice of Ba(In(1/3)Pb(1/3)M'(1/3))O3 (M = Sn, Pb; M' = Nb, Ta). X-ray diffraction, X-ray absorption spectroscopic, and energy dispersive spectroscopic microprobe analyses reveal that tetravalent Pb or Sn ions exist in the B-site of the perovskite lattice, along with In and Nb/Ta ions. According to diffuse UV-vis spectroscopic analysis, the Pb-containing quaternary metal oxides Ba(In(1/3)Pb(1/3)M'(1/3))O3 possess a much narrower band gap (E(g) approximately 1.48-1.50 eV) when compared to the ternary oxides Ba(In(1/2)M'(1/2))O3 (E(g) approximately 2.97-3.30 eV) and the Sn-containing Ba(In(1/3)Sn(1/3)M'(1/3))O3 derivatives (E(g) approximately 2.85-3.00 eV). Such a variation of band gap energy upon the substitution is attributable to the broadening of the conduction band caused by the dissimilar electronegativities of the B-site cations. In contrast to the ternary or the Sn-substituted quaternary compounds showing photocatalytic activity under UV-vis irradiation, the Ba(In(1/3)Pb(1/3)M'(1/3))O3 compounds induce an efficient photodegradation of 4-chlorophenol under visible light irradiation (lambda > 420 nm). The present results highlight that the substitution of electronegative non-transition metal cations can provide a very powerful way of developing efficient visible light harvesting photocatalysts through tuning of the band structure of a semiconductive metal oxide.

Dynamics and Novel Mechanisms of SN2 Reactions on ab Initio Analytical Potential Energy Surfaces.

PubMed

Szabó, István; Czakó, Gábor

2017-11-30

We describe a novel theoretical approach to the bimolecular nucleophilic substitution (S N 2) reactions that is based on analytical potential energy surfaces (PESs) obtained by fitting a few tens of thousands high-level ab initio energy points. These PESs allow computing millions of quasi-classical trajectories thereby providing unprecedented statistical accuracy for S N 2 reactions, as well as performing high-dimensional quantum dynamics computations. We developed full-dimensional ab initio PESs for the F - + CH 3 Y [Y = F, Cl, I] systems, which describe the direct and indirect, complex-forming Walden-inversion, the frontside attack, and the new double-inversion pathways as well as the proton-transfer channels. Reaction dynamics simulations on the new PESs revealed (a) a novel double-inversion S N 2 mechanism, (b) frontside complex formation, (c) the dynamics of proton transfer, (d) vibrational and rotational mode specificity, (e) mode-specific product vibrational distributions, (f) agreement between classical and quantum dynamics, (g) good agreement with measured scattering angle and product internal energy distributions, and (h) significant leaving group effect in accord with experiments.

Influence of mandatory generic substitution on pharmaceutical sales patterns: a national study over five years.

PubMed

Andersson, Karolina A; Petzold, Max G; Allebeck, Peter; Carlsten, Anders

2008-02-29

Mandatory generic substitution was introduced in Sweden in October 2002 in order to try to curb escalating pharmaceutical expenditure. The aim of this study was to investigate how sales patterns for substitutable and non-substitutable pharmaceuticals have developed since the introduction of mandatory generic substitution; furthermore, to compare sales patterns in different groups of the population, based on patients' age and gender. Five therapeutic groups comprising both substitutable and non-substitutable pharmaceuticals were included. The study period was from January 2000 to June 2005. National sales data were used, covering volumes of dispensed prescription medicines (expressed in defined daily doses per 1000 inhabitants and day) of each pharmacological substance in the therapeutic groups for each age and gender group. Sales patterns for substitutable and non-substitutable pharmaceuticals were compared using a descriptive approach. In most therapeutic groups there has been an increase in the volumes of substitutable pharmaceuticals sold since the introduction of the reform, ranging from one third to three times the initial volume; whereas the volumes of non-substitutable pharmaceuticals have levelled out or declined. There were few gender differences in sales patterns of substitutable and non-substitutable drugs. In three therapeutic groups, sales patterns differed across different age groups, and there was a tendency for volumes of recently introduced non-substitutable pharmaceuticals to be proportionally higher in the youngest age groups. Since the introduction of the reform, there has been a proportionally larger increase in sales of substitutable pharmaceuticals compared with sales of non-substitutable pharmaceuticals. This indicates that the reform might have contributed to larger sales of less expensive pharmaceuticals.

Numerical Modeling of Saturated Boiling in a Heated Tube

NASA Technical Reports Server (NTRS)

Majumdar, Alok; LeClair, Andre; Hartwig, Jason

2017-01-01

This paper describes a mathematical formulation and numerical solution of boiling in a heated tube. The mathematical formulation involves a discretization of the tube into a flow network consisting of fluid nodes and branches and a thermal network consisting of solid nodes and conductors. In the fluid network, the mass, momentum and energy conservation equations are solved and in the thermal network, the energy conservation equation of solids is solved. A pressure-based, finite-volume formulation has been used to solve the equations in the fluid network. The system of equations is solved by a hybrid numerical scheme which solves the mass and momentum conservation equations by a simultaneous Newton-Raphson method and the energy conservation equation by a successive substitution method. The fluid network and thermal network are coupled through heat transfer between the solid and fluid nodes which is computed by Chen's correlation of saturated boiling heat transfer. The computer model is developed using the Generalized Fluid System Simulation Program and the numerical predictions are compared with test data.

Ukraine’s Defense Dilemma

DTIC Science & Technology

1992-08-25

Ukraine has made environmental issues a top priority in any national security equation. The Chernobyl disaster of April 1986 is estimated to have...investment in Ukraine and in other former Soviet republics may be jeopardized by another environmental disaster of Chernobyl proportions. As an energy...adequate nuclear plants nor ailternative energy sources beyond coal to substitute for nuclear generated electricity. Some 16 Chernobyl -type graphite

Promoting Bio-Ethanol in the United States by Incorporating Lessons from Brazil's National Alcohol Program

ERIC Educational Resources Information Center

Du, Yangbo

2007-01-01

Current U.S. energy policy supports increasing the use of bio-ethanol as a gasoline substitute, which Brazil first produced on a large scale in response to the 1970s energy crises. Brazil's National Alcohol Program stood out among its contemporaries regarding its success at displacing a third of Brazil's gasoline requirements, primarily due to…

78 FR 68331 - Energy Conservation Program: Request for Exclusion of 100 Watt R20 Short Incandescent Reflector...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

... attempt to replace the same lamp that was previously installed. It is not typical consumer behavior to... energy conservation standards for certain commercial and industrial equipment and various consumer... Characteristics in Substitutes 1. Improved R20 Short Lamp 2. 60 W PAR16 Lamp 3. LED Lamps 4. Consumer Use of...

Changing the diet of a nation: Population/regulatory strategies for a developed economy.

PubMed

Nestle, M

2000-09-01

The principal nutritional problems of developed economies are related to the excessive and unbalanced intake of energy and nutrients. During the 20th century, as economies improved and food production became more efficient, conditions related to undernutrition were replaced by epidemics of coronary heart disease, certain cancers and other chronic conditions related to food overconsumption. In developed countries such as the United States, obesity became the predominant public health nutrition problem. To prevent obesity, people must consume less energy and be more active, but the food supplies of developed economies offer their populations amounts of energy that greatly exceed physiological need. Food overproduction causes competition in the food industry, limits its expansion, and leads food producers to invest heavily in marketing. To increase sales, food companies must encourage people to consume more of their products, substitute their products for others or develop new markets. Such efforts create an environment in which food is readily available at all times and readily overconsumed. Marketing expenditures for any single food product greatly exceed the total amounts available to governments for national campaigns to prevent chronic diseases. Existing government policies often support this environment through price supports and other means. To reverse obesity and its health consequences, governments need to consider ways to address the food environment through policies in education, agriculture, school meals, pricing, taxation and other means, as well as to develop mechanisms to fund new programme initiatives.

Characterization of PCBs from computers and mobile phones, and the proposal of newly developed materials for substitution of gold, lead and arsenic.

PubMed

Dervišević, Irma; Minić, Duško; Kamberović, Željko; Ćosović, Vladan; Ristić, Mirjana

2013-06-01

In this paper, we have analyzed parts of printed circuit board (PCB) and liquid crystal display (LCD) screens of mobile phones and computers, quantitative and qualitative chemical compositions of individual components, and complete PCBs were determined. Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) methods were used to determine the temperatures of phase transformations, whereas qualitative and quantitative compositions of the samples were determined by X-ray fluorescence spectrometry (XRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and scanning electron microscopy (SEM)-energy dispersive X-ray spectrometry (EDS) analyses. The microstructure of samples was studied by optical microscopy. Based on results of the analysis, a procedure for recycling PCBs is proposed. The emphasis was on the effects that can be achieved in the recycling process by extraction of some parts before the melting process. In addition, newly developed materials can be an adequate substitute for some of the dangerous and harmful materials, such as lead and arsenic are proposed, which is in accordance with the European Union (EU) Restriction of the use of certain hazardous substances (RoHS) directive as well as some alternative materials for use in the electronics industry instead of gold and gold alloys.

Long-chain alkane production by the yeast Saccharomyces cerevisiae.

PubMed

Buijs, Nicolaas A; Zhou, Yongjin J; Siewers, Verena; Nielsen, Jens

2015-06-01

In the past decade industrial-scale production of renewable transportation biofuels has been developed as an alternative to fossil fuels, with ethanol as the most prominent biofuel and yeast as the production organism of choice. However, ethanol is a less efficient substitute fuel for heavy-duty and maritime transportation as well as aviation due to its low energy density. Therefore, new types of biofuels, such as alkanes, are being developed that can be used as drop-in fuels and can substitute gasoline, diesel, and kerosene. Here, we describe for the first time the heterologous biosynthesis of long-chain alkanes by the yeast Saccharomyces cerevisiae. We show that elimination of the hexadecenal dehydrogenase Hfd1 and expression of a redox system are essential for alkane biosynthesis in yeast. Deletion of HFD1 together with expression of an alkane biosynthesis pathway resulted in the production of the alkanes tridecane, pentadecane, and heptadecane. Our study provides a proof of principle for producing long-chain alkanes in the industrial workhorse S. cerevisiae, which was so far limited to bacteria. We anticipate that these findings will be a key factor for further yeast engineering to enable industrial production of alkane based drop-in biofuels, which can allow the biofuel industry to diversify beyond bioethanol. © 2014 Wiley Periodicals, Inc.

Protonmotive force: development of electrostatic drivers for synthetic molecular motors.

PubMed

Crowley, James D; Steele, Ian M; Bosnich, Brice

2006-12-04

Ferrocene has been investigated as a platform for developing protonmotive electrostatic drivers for molecular motors. When two 3-pyridine groups are substituted to the (rapidly rotating) cyclopentadienyl (Cp) rings of ferrocene, one on each Cp, it is shown that the (Cp) eclipsed, pi-stacked rotameric conformation is preferred both in solution and in the solid state. Upon quaternization of both of the pyridines substituents, either by protonation or by alkylation, it is shown that the preferred rotameric conformation is one where the pyridinium groups are rotated away from the fully pi-stacked conformation. Electrostatic calculations indicate that the rotation is caused by the electrostatic repulsion between the charges. Consistently, when the pi-stacking energy is increased pi-stacked population increases, and conversely when the electrostatic repulsion is increased pi-stacked population is decreased. This work serves to provide an approximate estimate of the amount of torque that the electrostatically driven ferrocene platform can generate when incorporated into a molecular motor. The overall conclusion is that the electrostatic interaction energy between dicationic ferrocene dipyridyl systems is similar to the pi-stacking interaction energy and, consequently, at least tricationic systems are required to fully uncouple the pi-stacked pyridine substituents.

Electron Transport and Nonlinear Optical Properties of Substituted Aryldimesityl Boranes: A DFT Study

PubMed Central

Pandith, Altaf Hussain; Islam, Nasarul

2014-01-01

A comprehensive theoretical study was carried out on a series of aryldimesityl borane (DMB) derivatives using Density Functional theory. Optimized geometries and electronic parameters like electron affinity, reorganization energy, frontiers molecular contours, polarizability and hyperpolarizability have been calculated by employing B3PW91/6-311++G (d, p) level of theory. Our results show that the Hammett function and geometrical parameters correlates well with the reorganization energies and hyperpolarizability for the series of DMB derivatives studied in this work. The orbital energy study reveals that the electron releasing substituents increase the LUMO energies and electron withdrawing substituents decrease the LUMO energies, reflecting the electron transport character of aryldimesityl borane derivatives. From frontier molecular orbitals diagram it is evident that mesityl rings act as the donor, while the phenylene and Boron atom appear as acceptors in these systems. The calculated hyperpolarizability of secondary amine derivative of DMB is 40 times higher than DMB (1). The electronic excitation contributions to the hyperpolarizability studied by using TDDFT calculation shows that hyperpolarizability correlates well with dipole moment in ground and excited state and excitation energy in terms of the two-level model. Thus the results of these calculations can be helpful in designing the DMB derivatives for efficient electron transport and nonlinear optical material by appropriate substitution with electron releasing or withdrawing substituents on phenyl ring of DMB system. PMID:25479382

Achieving Land, Energy, and Environmental Compatibility: Utility-Scale Solar Energy Potential and Land-Use in California

NASA Astrophysics Data System (ADS)

Hoffacker, M. K.; Hernandez, R. R.; Field, C. B.

2013-12-01

Solar energy is an archetype renewable energy technology with great potential to reduce greenhouse gas emissions when substituted for carbon-intensive energy. Utility-scale solar energy (USSE; i.e., > 1 MW) necessitates large quantities of space making the efficient use of land for USSE development critical to realizing its full potential. However, studies elucidating the interaction between land-use and utility-scale solar energy (USSE) are limited. In this study, we assessed 1) the theoretical and technical potential of terrestrial-based USSE systems, and 2) land-use and land-cover change impacts from actual USSE installations (> 20 MW; planned, under construction, operating), using California as a case study due to its early adoption of renewable energy systems, unique constraints on land availability, immense energy demand, and vast natural resources. We used topo-climatic (e.g., slope, irradiance), infrastructural (e.g., proximity to transmission lines), and ecological constraints (e.g., threatened and endangered species) to determine highly favorable, favorable, and unfavorable locations for USSE and to assess its technical potential. We found that the theoretical potential of photovoltaic (PV) and concentrating solar power (CSP) in California is 26,097 and 29,422 kWh/m2/day, respectively. We identified over 150 planned, under construction, and operating USSE installations in California, ranging in size from 20 to 1,000 MW. Currently, 29% are located on shrub- and scrublands, 23% on cultivated crop land, 13% on pasture/hay areas, 11% on grassland/herbaceous and developed open space, and 7% in the built environment. Understanding current land-use decisions of USSE systems and assessing its future potential can be instructive for achieving land, energy, and environmental compatibility, especially for other global regions that share similar resource demands and limitations.

Preparation and Characterization of Hydroxyapatite-Silica Composite Nanopowders

NASA Astrophysics Data System (ADS)

Latifi, S. M.; Fathi, M. H.; Golozar, M. A.

One of the most important objectives in the field of biomaterials science and engineering is development of new materials as bone substitutes. Silica (SiO2) has an important role in the biomineralization and biological responses. The aim of this research was to prepare and characterize hydroxyapatite-silica (HA-SiO2) composite nanopowder with different content of silica. Hydroxyapatite-silica composite nanopowders with 20 and 40 wt% silica were prepared using a sol-gel method at 600°C with phosphoric pentoxide and calcium nitrate tetrahydrate as a source of hydroxyapatite; also, tetraethylorthosilicate and methyltriethoxisilane as a source of silica. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) techniques were used for characterization and evaluation of the products. The results indicated the presence of nanocrystalline hydroxyapatite phase beside amorphous silica phase in prepared composite nanopowders. Moreover, by increasing the content of silica in composite nanopowders, the crystallinity will be decreased,and the ability of the product as a bone substitute material might be controlled by changing the content of the ingredients and subsequently its structure.

Chemical substitution study on magnetism and superconductivity in Ce1-x SmxCoIn5

NASA Astrophysics Data System (ADS)

Pouse, N.; Jang, S.; White, B.; Ran, S.; Maple, M. B.; Almasan, C. C.

We report electrical resistivity, magnetization, and specific heat measurement measurements on the Ce1- x SmxCoIn5 system for 0 <= x <= 1. Superconductivity in CeCoIn5 is suppressed with increasing Sm concentrations up to x = 0.1, above which there is no evidence for superconductivity from measurements down to 50 mK; antiferromagnetic ordering in SmCoIn5 persists deep into the Ce-rich side, and is not completely suppressed until x = 0.25. We have observed the development of a low-temperature upturn in electrical resistivity for 0.70 <= x <= 0.85 which is consistent with behavior for a single-ion impurity Kondo effect and suggests that the substitution of Sm for Ce causes a change of the relative strength of competing Kondo and Ruderman-Kittel-Kasuya-Yosida energy scales. Research at UCSD is supported by the US DOE BES under Grant No. DE-FG02-04-ER46105, the US NSF under Grant No. DMR-1206553, and research at Kent State U. is supported by NSF under Grant No. DMR-1505826.

Linear free energy study of ring-substituted aniline ozonation for developing treatment of aniline-based pesticide wastes.

PubMed

Pierpoint, A C; Hapeman, C J; Torrents, A

2001-08-01

The relative rate constants for the reaction of ozone were determined for several substituted anilines in aqueous solutions at pH 6.5 and 1.5. At pH 6.5, with the exception of m- and p-nitroaniline, the rate constants obey Hammett's equation: log(k(X)/k(H)) = rho sigma. The departure of m- and p-nitroaniline may be explained by direct conjugation of the reaction center. The commonly used sigma(p)(-) value of 1.27, which extends the range of applicability of the Hammett equation, was insufficient to account for the conjugation effects on ozonation of p-nitroaniline; rho = -1.48 (R = 0.973). Use of amine group atomic charge determinations significantly improved correlations: (k(X)/k(H)) = 48.7 delta - 18.2 (R = 0.996). A linear plot of Hammett constants versus relative rate data at pH 1.5 showed poor correlation: rho = 0.72 (R = 0.572). Poor correlation was similarly observed for amine group atomic charge determinations, suggesting varied reaction mechanisms.

Improved ferroelectric and photoluminescence properties in Pr3+ substituted Na0.5Bi0.5TiO3 synthesized using hydrothermal route

NASA Astrophysics Data System (ADS)

Goutham, Cilaveni; Kandula, Kumara Raja; Raavi, Sai Santhosh Kumar; Asthana, Saket

2018-04-01

Nanocrystalline Pr3+ substituted NBT was synthesized using hydrothermal technique. Pr3+ modifies the ferroelectric NBT optically active and enhances the electrical properties with small structural changes. Aiming to the development of the bottom up optoelectronic devices this optimized nanoscale Na0.5Bi0.5-xPrxTiO3(x = 0.005) compound is synthesized hydrothermally. X-ray diffraction pattern shows that the system is stabilized in the Rhombohedral (space groupR3c) phase indicating the local strain inhomogeneity. PE loop shows that there is a decrement in the Ec value compared with compounds synthesized using conventional methods. The strong red emission assigned to prominent transition of the Pr3+ ions at 610nm was observed along with weak blue-green emission, indicating the potential use of the system. Energy transfer from host system to Pr3+ ions is responsible for red emission while blue green emission is due to quenching of 3P0 induced by intervalence charge transfer state.

Fluorescence Visual Detection of Herbal Product Substitutions at Terminal Herbal Markets by CCP-based FRET technique.

PubMed

Jiang, Chao; Yuan, Yuan; Yang, Guang; Jin, Yan; Liu, Libing; Zhao, Yuyang; Huang, Luqi

2016-10-21

Inaccurate labeling of materials used in herbal products may compromise the therapeutic efficacy and may pose a threat to medicinal safety. In this paper, a rapid (within 3 h), sensitive and visual colorimetric method for identifying substitutions in terminal market products was developed using cationic conjugated polymer-based fluorescence resonance energy transfer (CCP-based FRET). Chinese medicinal materials with similar morphology and chemical composition were clearly distinguished by the single-nucleotide polymorphism (SNP) genotyping method. Assays using CCP-based FRET technology showed a high frequency of adulterants in Lu-Rong (52.83%) and Chuan-Bei-Mu (67.8%) decoction pieces, and patented Chinese drugs (71.4%, 5/7) containing Chuan-Bei-Mu ingredients were detected in the terminal herbal market. In comparison with DNA sequencing, this protocol simplifies procedures by eliminating the cumbersome workups and sophisticated instruments, and only a trace amount of DNA is required. The CCP-based method is particularly attractive because it can detect adulterants in admixture samples with high sensitivity. Therefore, the CCP-based detection system shows great potential for routine terminal market checks and drug safety controls.

Discovery of melanocortin ligands via a double simultaneous substitution strategy based on the Ac-His-DPhe-Arg-Trp-NH2 template.

PubMed

Todorovic, Aleksandar; Lensing, Cody J; Holder, Jerry Ryan; Scott, Joseph W; Sorensen, Nicholas B; Haskell-Luevano, Carrie

2018-05-21

The melanocortin system regulates an array of diverse physiological functions including pigmentation, feeding behavior, energy homeostasis, cardiovascular regulation, sexual function, and steroidogenesis. Endogenous melanocortin agonist ligands all possess the minimal messaging tetrapeptide sequence His-Phe-Arg-Trp. Based on this endogenous sequence, the Ac-His1-DPhe2-Arg3-Trp4-NH 2 tetrapeptide has previously been shown to be a useful scaffold when utilizing traditional positional scanning approaches to modify activity at the various melanocortin receptors (MC1-5R). The study reported herein was undertaken to evaluate a double simultaneous substitution strategy as an approach to further diversify the Ac-His1-DPhe2-Arg3-Trp4-NH 2 tetrapeptide with concurrent introduction of natural and unnatural amino acids at positions 1, 2, or 4 as well as an octanoyl residue at the N-terminus. The designed library includes the following combinations: (A) double simultaneous substitution at capping group position (Ac) together with position 1, 2, or 4, (B) double simultaneous substitution at position 1 and 2, (C) double simultaneous substitution at position 1 and 4, and (D) double simultaneous substitution at position 2 and 4. Several lead ligands with unique pharmacologies were discovered in the current study including antagonists targeting the neuronal mMC3R with minimal agonist activity and ligands with selective profiles for the various melanocortin subtypes. The results suggest that the double simultaneous substitution strategy is a suitable approach in altering melanocortin receptor potency, selectivity, or converting agonists into antagonists and vice versa.

Modulation in magnetic exchange interaction, core shell structure and Hopkinson's peak with chromium substitution into Ni0.75Co0.25Fe2O4 nano particles

NASA Astrophysics Data System (ADS)

Uday Bhasker, S.; Choudary, G. S. V. R. K.; Reddy, M. V. Ramana

2018-05-01

The ever growing applications and ever evolving challenges of magnetic nano particles has been motivating the researchers from various disciplines towards this area of magnetic nano particles. Cation substitutional effect on the magnetic structure of the nanoparticles forms a crucial aspect in their applications. Here the environmentally benign auto combustion method was employed to synthesize chromium substituted nickel cobalt ferrite (Ni0.75Co0.25Fe2-xCrxO4; x = 0, 0.10, 0.15) nano particles, from aqueous metal nitrate solutions. Chromium substitution has shown its effect on the structural, magnetic and electrical properties of Ni0.75Co0.25Fe2O4. Structural and phase analysis of the prepared samples show increased phase purity of ferrite sample with increasing Cr substitution. The TEM (Transmission Electron Microscope) image confirms the nano size of the particles, EDS (Energy dispersive X-ray Spectroscopy) has supported the stoichiometry of the prepared samples and FTIR (Fourier-transform infrared spectroscopic) analysis confirms the spinel structure and also suggests cation redistributions with chromium substitution. VSM (Vibrational Sample Magnetometer) is used to study the magnetic properties through magnetic hysteresis (M-H) loop and magnetic Hopkinson effect. All samples show hysteresis and show reduction in magnetic properties with increase in chromium content. The thermo magnetic study shows Hopkinson peak(s) in the magnetization vs. temperature (M-T) graph and also shows variation in the nature of Hopkinson peak with chromium substitution. Possible reasons for the changes in the nature of the peak are discussed.

New Strategy to Reduce Hypertriglyceridemia During Parenteral Nutrition While Maintaining Energy Intake.

PubMed

Mateu-de Antonio, Javier; Florit-Sureda, Marta

2016-07-01

Hypertriglyceridemia is a frequent metabolic complication associated with fat administration in parenteral nutrition (PN). No clear guidelines have been published on how to proceed once hypertriglyceridemia has been detected. A new strategy could be to substitute the initial fat emulsion with another emulsion with faster clearance. Our objective was to determine the effectiveness in reducing triglyceridemia values, maintaining the caloric intake, and improving nutrition parameters in patients who had moderate hypertriglyceridemia during PN when an olive oil-based fat emulsion (OOFE) was substituted with a multiple-source oil fat emulsion (MOFE). We also assessed the safety of this substitution in hepatic and glycemic profiles. We performed a retrospective, observational study that included 38 adult patients to whom OOFE in PN was substituted with MOFE when moderate hypertriglyceridemia (≥250-400 mg/dL) was detected. Triglyceridemia values decreased in 36 (94.7%) patients. The mean reduction was 71 (88-22) mg/dL. Fat load was slightly reduced after substitution (-0.14 [-0.23 to 0] g/kg/d; P < .001), but total caloric intake increased from 22.5 (19.7-25.1) to 23.1 (19.8-26.8) kcal/kg/d (P = .053). After substitution, nutrition parameters improved, liver parameters remained unchanged, and insulin requirements increased. The substitution of OOFE with MOFE in patients with moderate hypertriglyceridemia during PN resulted in a reduction in triglyceridemia values of about 70 mg/dL. That allowed maintaining the caloric intake and improved nutrition parameters without affecting the hepatic profile. For some patients, insulin requirements increased moderately. © 2014 American Society for Parenteral and Enteral Nutrition.

24 CFR 983.206 - HAP contract amendments (to add or substitute contract units).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false HAP contract amendments (to add or... Contract § 983.206 HAP contract amendments (to add or substitute contract units). (a) Amendment to substitute contract units. At the discretion of the PHA and subject to all PBV requirements, the HAP contract...

"F-The French Connection."

ERIC Educational Resources Information Center

Sleigh, John; Plevey, Ray

1986-01-01

Provides background information for teachers on the chemistry of flourine. Points out that it links aerosols with refrigerants, anaesthetics with fire-fighting agents, batteries with blood substitutes, and atomic energy with the steel, petroleum, and aluminum industries. (JN)

Integrated assessment of the health and economic benefits of long-term renewable energy development in China

NASA Astrophysics Data System (ADS)

Dai, H.; Xie, Y.; Zhang, Y.

2017-12-01

Context/Purpose: Power generation from renewable energy (RE) could substitute huge amount of fossil energy in the power sector and have substantial co-benefits of air quality and human health improvement. In 2016, China National Renewable Energy Center (CNREC) released China Renewable Energy Outlook, CREO2016 and CREO2017, towards 2030 and 2050, respectively, in which two scenarios are proposed, namely, a conservative "Stated Policy" scenario and a more ambitious "High RE" scenario. This study, together with CNREC, aims to quantify the health and economic benefits of developing renewable energy at the provincial level in China up to 2030 and 2050. Methods: For this purpose, we developed an integrated approach that combines a power dispatch model at CNREC, an air pollutant emission projection model using energy consumption data from the Long-range Energy Alternatives Planning System (LEAP) model, an air quality model (GEOS-Chem at Harvard), an own-developed health model, and a macro economic model (Computable General Equilibrium model). Results: All together, we attempt to quantify how developing RE could reduce the concentration of PM2.5 and ozone in 30 provinces of China, how the human health could be improved in terms of mortality, morbidity and work hour loss, and what is the economic value of the health improvement in terms of increased GDP and the value of statistical life lost. The results show that developing RE as stated in the CREO2016 could prevent chronic mortality of 286 thousand people in China in 2030 alone, the value of saved statistical life is worthy 1200 billion Yuan, equivalent to 1.2% of GDP. In addition, averagely, due to reduced mortality and improved morbidity each person could work additionally by 1.16 hours per year, this could contribute to an increase of GDP by 0.1% in 2030. The assessment up to 2050 is still underway. Interpretation: The results imply that when the external benefit of renewable energy is taken into account, RE could be cost competitive compared with fossil fuel use. In other words, fossil fuel combustion is not so cheap as it appears when considering its external cost in terms of human health damage. Conclusion: Our study finds that developing renewable energy could bring substantial health and economic benefits for China.

Effect of substitution of low linolenic acid soybean oil for hydrogenated soybean oil on fatty acid intake.

PubMed

DiRienzo, Maureen A; Astwood, James D; Petersen, Barbara J; Smith, Kim M

2006-02-01

Low linolenic acid soybean oil (LLSO) has been developed as a substitute for hydrogenated soybean oil to reduce intake of trans FA while improving stability and functionality in processed foods. We assessed the dietary impact of substitution of LLSO for hydrogenated soybean oil (HSBO) used in several food categories. All substitutions were done using an assumption of 100% market penetration. The impact of this substitution on the intake of five FA and trans FA was assessed. Substitution of LLSO for current versions of HSBO resulted in a 45% decrease in intake of trans FA. Impacts on other FA intakes were within the realm of typical dietary intakes. No decrease in intake of alpha-linolenic acid was associated with the use of LLSO in place of HSBO because LLSO substitutes for HSBO that are already low in alpha-linolenic acid.

Theoretical investigations of the thermochemistry, structures, and internal rotation of conjugated polyynes

NASA Astrophysics Data System (ADS)

Jarowski, Peter D.

Chapter 1 discusses the thermochemistry of conjugated double and triple bonds. The conjugation stabilization energies of dienes and diynes are considerably larger than estimates based on heat of hydrogenation differences between 1,3-butadiyne and 1-butyne as well as between 1,3-butadiene and 1-butene. Such comparisons do not take into account the counterbalancing hyperconjugative stabilization of the partially hydrogenated products by their ethyl groups. When alkyl hyperconjugation is considered, the conjugation stabilization of diynes (≈ 9.3 kcal/mol) is found by two methods (involving isomerization of non-conjugated into conjugated isomers and heats of hydrogenation) to be larger than that of dienes (≈ 8.2 kcal/mol). In Chapter 2 the stabilization of substituted organic radicals, relative to methyl, are computed using bond separation energies and the block localized wavefunction method. These energies are typically evaluated from C-H bond dissociation energies (computed here by the CBS-RAD method). However, this method gives stabilization energies of an increasing number of mono-, di-, and tri-substituted vinyl and ethynyl substituents, which differ from the predictions of Perturbation Molecular Orbital (PMO) and Huckel Molecular Orbital (HMO) theory. The saturation (attenuation) effect for both series should be monotonic and small. Instead, the attenuation computed by the allylic series is larger than that predicted by HMO theory and the behavior of the propargylic series is erratic. These discrepancies arise from the use of bond dissociation energy data in the evaluations, which depend not only on the stabilization of the radicals, but also on the substantial substituent effects (e.g., hyperconjugation) on the energies of the reference hydrocarbons. New evaluation schemes are proposed that avoid such complications and thus estimate radical stabilization effects directly; the results agree with PMO and HMO theories. Substitution effects are analyzed using isodesmic equations with CBS-RAD data and also with the block localized wavefunction (BLW) method. The new estimates give essentially the same vinyl (22.3 kcal/mol) and ethynyl (21.9 kcal/mol) stabilization energies in the allyl and propargyl radicals, contrary to conventional evaluations. Likewise, the vinyl and ethynyl stabilizations in di-substituted and tri-substituted radicals are similar. These conclusions are corroborated with the block localized wavefunction (BLW) method, which is used to analyze resonance stabilization energies in the radical systems and hyperconjugative stabilization energies in the reference hydrocarbons. Chapter 3 presents the structures, heats of formation, and strain energies of diacetylene (buta-1,3-diynediyl) expanded molecules computed with ab initio and molecular mechanics calculations. Expanded cubane, prismane, tetrahedrane, and expanded monocyclics and bicyclics were optimized at the HF/6-31G(d) and B3LYP/6-31G(d) levels. The heats of formation of these systems were obtained from isodesmic equations at the HF/6-31G(d) level. Heats of formation were also calculated from Benson group equivalents. The strain energies of these expanded molecules were estimated by several independent methods. An adapted MM3* molecular mechanics force field, specifically parameterized to treat conjugated acetylene units, was employed for one measure of strain energy and as an additional method for structural analysis. Expanded dodecahedrane and icosahedrane were calculated by this method. Expanded molecules were considered structurally in the context of their potential material applications. Chapter 4 addresses the computation of the rotational barriers of substituted ethynlene and butatriene as well as their geometric and electronic structures. The barriers to internal rotation of methylated, ethynylated, and vinylated butatrienes and alkenes were calculated at the CASPT2/6-31G(d)//B3LYP/6-31G(d) level. Calculated butatriene rotational barriers are lower than analogous alkenes, but there is a larger variance in rotational barrier for alkenes than for butatrienes. The barriers to rotation were analyzed by isodesmic equations designed to estimate the substituent effects in the ground (GS) and transition state (TS) individually. The GSs of both series are stabilized to roughly the same extent. In contrast, the TSs of butatrienes are more stabilized overall than those of alkenes. Much of the stabilization in the TS of butatrienes comes from the internal triple bond and not from the substituent. Estimation of the substituent stabilization alone reveals the TSs of ethylenes to be more stabilized by substitution than butatrienes. In Chapter 5 the energetic and structural changes taking place upon rotation of the central phenylene of 1,4-bis(3,3,3-triphenylpropynyl)benzene molecular gyroscopes in the solid-state were computed using molecular mechanics calculations. Pseudopolymorphic crystals of a benzene clathrate (1A) and a desolvated form (1B) were analyzed with models that account for varying degrees of freedom within the corresponding lattices. The calculated rotational barriers in a rigid lattice approximation, 78 kcal/mol for 1A and 72 kcal/mol for 1B, are about five times greater than those previously measured by variable temperature 13C CPMAS NMR and quadrupolar echo 2H NMR line shape analysis; 12.8 kcal/mol for 1A and 14.6 kcal/mol for 1B. The rotational barriers calculated with a model that restricts whole body rotation and translational motions but allows for internal rotations give results that are consistent with experiment. The calculated barriers for 1A and 1B are 15.5 kcal/mol and 16.2 kcal/mol, respectively. The differences between the two models are attributed to the effect of correlated motions of the lattice and the rotating group, which are evident from the structural analysis of the atomic position data as a function of the dihedral angle of the rotator. The displacements of neighboring molecules near the rotary transition states for 1A and 1B can be as large as 2.7 and 1.1 A, respectively. While the displacement of interpenetrating phenyl rings from neighboring rotors proximal to the event are significant for both 1A and 1B, six-fold (C6) benzene rotations in clathrate 1A were found to be directly correlated to the rotation the phenylene rotator. The Trueblood model estimates solid-state rotational barriers by fitting anisotropic displacement parameters (thermal ellipsoids) from X-ray diffraction data determined at varying temperature to quadratic or sinusoidal functions that approximate the potential energy profile to libration. The applicability of this model towards substituted and unsubstituted 1,4-bis(3,3,3-triphenylpropynyl)benzene molecular rotor crystals is gauged using computational data generated from molecular mechanics force field calculations. Unsubstituted and mono-fluoro, -amino, and -nitro, substituted derivatives are calculated. Benzene clathrate polymorphs are also included. Estimated barriers agree well with experimental data, although they are slightly overestimated. The barriers are not strictly correlated to substituent volume and reside within a small range of values.

Proof of concept of a new autologous skin substitute for the treatment of deep wounds in dogs.

PubMed

Ramió-Lluch, L; Cerrato, S; Brazis, P; Rabanal, R M; Fondevila, D; Puigdemont, A

2017-12-01

Autologous skin grafts are effective for the repair of large skin wounds, but the availability of large amounts of skin is often limited. Through bioengineering, several autologous skin substitutes have been developed for use in human clinical practice. However, few skin substitutes are available for use in animals. The aim of this study was to develop and assess an engineered autologous skin substitute for the treatment of deep wounds in veterinary medicine. Canine keratinocytes and fibroblasts were isolated after double enzyme digestion from 8mm punch biopsies from four healthy Beagle dogs. Skin substitutes were constructed on a fibrin-based matrix and grafting capacity was assessed by xenografting in six athymic mice. Bioengineered autologous skin was assessed clinically in two dogs with large deep skin wounds. The canine skin construct was ready for use within 12-14days after the initial biopsy specimens were obtained. Grafting capacity in this model was confirmed by successful grafting of the construct in athymic mice. In both dogs, grafts were established and permanent epithelialisation occurred. Histological studies confirmed successful grafting. This full thickness skin substitute developed for the management of large skin defects in dogs appears to be a safe and useful tool for clinical veterinary practice. Further studies are needed to validate its efficacy for the treatment of deep wounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Introduction of substitutional and non-substitutional dopants into MgB2 in high pressure/Temperature or non-equilibrium regimes

NASA Astrophysics Data System (ADS)

Sumption, Mike

2013-03-01

In an attempt to study the effect of doping of MgB2 under conditions leading to efficient doping, we used both an high temperature/high pressure induction furnace to dope into MgB2 bulks at temperatures up to 1600 C and 1500 Psi, and thin film, PLD multilayer and mixed layer film fabrication. The high temperature/high pressure formation was used to explore the solubility at high temperatures of various dopants, and the thin film formation was an attempt to use non-equilibrium conditions to inject dopants more effectively. The dopants used were C, Ti, and Zr. C was seen to reach a maximal level at 4 at% C site substituted into MgB2, as evidenced by EPMA and XRD results. Zr, of interest as a possible Mg site substitution in MgB2 was not seen to enter into the MgB2 phase (instead segregating) in the bulk high temperature/high pressure experiments, but was seen to enter in during PLD, as evidenced by STEM and XRD results. Ti additions were attempted in the high pressures and temperature rig, with some evidence for dopant introduction. Critical field measurements on the Zr doped samples where seen to suppress Bc2 for all except very low levels of Ti addition, presumably associated with the much greater doping efficiency. This work was supported by the U.S. Department of Energy, High Energy Physics university Grant No. DE-FG02-95ER40900

Reducing Mg Acceptor Activation-Energy in Al0.83Ga0.17N Disorder Alloy Substituted by Nanoscale (AlN)5/(GaN)1 Superlattice Using MgGa δ-Doping: Mg Local-Structure Effect

PubMed Central

Zhong, Hong-xia; Shi, Jun-jie; Zhang, Min; Jiang, Xin-he; Huang, Pu; Ding, Yi-min

2014-01-01

Improving p-type doping efficiency in Al-rich AlGaN alloys is a worldwide problem for the realization of AlGaN-based deep ultraviolet optoelectronic devices. In order to solve this problem, we calculate Mg acceptor activation energy and investigate its relationship with Mg local structure in nanoscale (AlN)5/(GaN)1 superlattice (SL), a substitution for Al0.83Ga0.17N disorder alloy, using first-principles calculations. A universal picture to reduce acceptor activation energy in wide-gap semiconductors is given for the first time. By reducing the volume of the acceptor local structure slightly, its activation energy can be decreased remarkably. Our results show that Mg acceptor activation energy can be reduced significantly from 0.44 eV in Al0.83Ga0.17N disorder alloy to 0.26 eV, very close to the Mg acceptor activation energy in GaN, and a high hole concentration in the order of 1019 cm−3 can be obtained in (AlN)5/(GaN)1 SL by MgGa δ-doping owing to GaN-monolayer modulation. We thus open up a new way to reduce Mg acceptor activation energy and increase hole concentration in Al-rich AlGaN. PMID:25338639

The study of the application of crystalline silicone solar cell type for a temporary flood camp

NASA Astrophysics Data System (ADS)

Hendarti, R.; Katarina, W.; Wangidjaja, W.

2017-12-01

During flood period, most of temporary evacuation shelters in Jakarta are lack in electricity because the local electricity company turned the electricity off to avoid any electrical problem because of the high water level over the flooded area. Whereas, the local electricity or the grid is the main energy source for the lighting and water pump machine, therefore the energy source becomes a significant issue during this period. Currently, the local government has already provided diesel generators to substitute the local grid when it is off, however, the amount of the generators is still limited. This study, therefore, investigated an alternative energy for the electricity, particularly solar energy and this paper presents an analysis of the Jakarta duration of sunshine during rainy seasons in order to investigate which Crystalline Silicone solar cell type that can be implemented optimally for energy supply in the period of flood evacuation as well as for the shelter. A deep analysis on literature review was conducted on the three types of Crystalline Silicone solar cell, Jakarta local weather. Furthermore, the standard of International Federation of Red Cross and Red Crescent Societies (IFRC) was also studied for the shelter design. The results of this study could be used as a reference for the local authority in providing the substitute energy supply in the temporary evacuation area during flood period in which the solar energy source could be also attached on the shelter.

Modification of the band offset in boronitrene

NASA Astrophysics Data System (ADS)

Obodo, K. O.; Andrew, R. C.; Chetty, N.

2011-10-01

Using density functional methods within the generalized gradient approximation implemented in the Quantum Espresso codes, we modify the band offset in a single layer of boronitrene by substituting a double line of carbon atoms. This effectively introduces a line of dipoles at the interface. We considered various junctions of this system within the zigzag and armchair orientations. Our results show that the “zigzag-short” structure is energetically most stable, with a formation energy of 0.502 eV and with a band offset of 1.51 eV. The “zigzag-long” structure has a band offset of 1.99 eV. The armchair structures are nonpolar, while the zigzag-single structures show a charge accumulation for the C-substituted B and charge depletion for the C-substituted N at the junction. Consequently there is no shifting of the bands.

Diels–Alder Exo-Selectivity in Terminal-Substituted Dienes and Dienophiles: Experimental Discoveries and Computational Explanations

PubMed Central

Lam, Yu-hong; Cheong, Paul Ha-Yeon; Mata, José M. Blasco; Stanway, Steven J.; Gouverneur, Véronique; Houk, K. N.

2009-01-01

The Diels–Alder reactions of a series of silyloxydienes and silylated dienes with acyclic α,β-unsaturated ketones and N-acyloxazolidinones have been investigated. The endo/exo stereochemical outcome is strongly influenced by the substitution pattern of the reactants. High exo selectivity was observed when the termini of the diene and the dienophile involved in the shorter forming bond are both substituted, while the normal endo preference was found otherwise. The exo-selective asymmetric Diels–Alder reactions using Evans’ oxazolidinone chiral auxiliary furnished a high level of π-facial selectivity in the same sense as their well-documented endo-selective counterparts. Computational results of these Diels–Alder reactions were consistent with the experimental endo/exo selectivity in most cases. A twist-asynchronous model accounts for the geometries and energies of the computed transition structures. PMID:19154113

Modelling Electrical Energy Consumption in Automotive Paint Shop

NASA Astrophysics Data System (ADS)

Oktaviandri, Muchamad; Safiee, Aidil Shafiza Bin

2018-03-01

Industry players are seeking ways to reduce operational cost to sustain in a challenging economic trend. One key aspect is an energy cost reduction. However, implementing energy reduction strategy often struggle with obstructions, which slow down their realization and implementation. Discrete event simulation method is an approach actively discussed in current research trend to overcome such obstructions because of its flexibility and comprehensiveness. Meanwhile, in automotive industry, paint shop is considered the most energy consumer area which is reported consuming about 50%-70% of overall automotive plant consumption. Hence, this project aims at providing a tool to model and simulate energy consumption at paint shop area by conducting a case study at XYZ Company, one of the automotive companies located at Pekan, Pahang. The simulation model was developed using Tecnomatix Plant Simulation software version 13. From the simulation result, the model was accurately within ±5% for energy consumption and ±15% for maximum demand after validation with real system. Two different energy saving scenarios were tested. Scenario 1 was based on production scheduling approach under low demand situation which results energy saving up to 30% on the consumption. Meanwhile scenario 2 was based on substituting high power compressor with the lower power compressor. The results were energy consumption saving of approximately 1.42% and maximum demand reduction about 1.27%. This approach would help managers and engineers to justify worthiness of investment for implementing the reduction strategies.

Vitreous Substitutes: Old and New Materials in Vitreoretinal Surgery

PubMed Central

Panico, Claudio; Eandi, Chiara M.

2017-01-01

Recent developments in vitreoretinal surgery have increased the need for suitable vitreous substitutes. A successful substitute should maintain all the physical and biochemical properties of the original vitreous, be easy to manipulate, and be long lasting. Substitutes can be gaseous or liquid, both of which have associated advantages and disadvantages related to their physical properties and use. Furthermore, new surgical techniques with smaller vitreoretinal instruments have driven the use of more viscous substitutes. In this review, we analyze and discuss the most frequently used vitreous substitutes and look ahead to future alternatives. We classify these compounds based on their composition and structure, discuss their clinical use with respect to their associated advantages and disadvantages, and analyze how new vitreoretinal surgical techniques have modified their use. PMID:28785482

Comparing the greenhouse gas emissions from three alternative waste combustion concepts

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

Vainikka, Pasi, E-mail: pasi.vainikka@vtt.fi; Tsupari, Eemeli; Sipilae, Kai

2012-03-15

Highlights: Black-Right-Pointing-Pointer Significant GHG reductions are possible by efficient WtE technologies. Black-Right-Pointing-Pointer CHP and high power-to-heat ratio provide significant GHG savings. Black-Right-Pointing-Pointer N{sub 2}O and coal mine type are important in LCA GHG emissions of FBC co-combustion. Black-Right-Pointing-Pointer Substituting coal and fuel oil by waste is beneficial in electricity and heat production. Black-Right-Pointing-Pointer Substituting natural gas by waste may not be reasonable in CHP generation. - Abstract: Three alternative condensing mode power and combined heat and power (CHP) waste-to-energy concepts were compared in terms of their impacts on the greenhouse gas (GHG) emissions from a heat and power generation system.more » The concepts included (i) grate, (ii) bubbling fluidised bed (BFB) and (iii) circulating fluidised bed (CFB) combustion of waste. The BFB and CFB take advantage of advanced combustion technology which enabled them to reach electric efficiency up to 35% and 41% in condensing mode, respectively, whereas 28% (based on the lower heating value) was applied for the grate fired unit. A simple energy system model was applied in calculating the GHG emissions in different scenarios where coal or natural gas was substituted in power generation and mix of fuel oil and natural gas in heat generation by waste combustion. Landfilling and waste transportation were not considered in the model. GHG emissions were reduced significantly in all of the considered scenarios where the waste combustion concepts substituted coal based power generation. With the exception of condensing mode grate incinerator the different waste combustion scenarios resulted approximately in 1 Mton of fossil CO{sub 2}-eq. emission reduction per 1 Mton of municipal solid waste (MSW) incinerated. When natural gas based power generation was substituted by electricity from the waste combustion significant GHG emission reductions were not achieved.« less

Al-, Y-, and La-doping effects favoring intrinsic and field induced ferroelectricity in HfO2: A first principles study

NASA Astrophysics Data System (ADS)

Materlik, Robin; Künneth, Christopher; Falkowski, Max; Mikolajick, Thomas; Kersch, Alfred

2018-04-01

III-valent dopants have shown to be most effective in stabilizing the ferroelectric, crystalline phase in atomic layer deposited, polycrystalline HfO2 thin films. On the other hand, such dopants are commonly used for tetragonal and cubic phase stabilization in ceramic HfO2. This difference in the impact has not been elucidated so far. The prospect is a suitable doping to produce ferroelectric HfO2 ceramics with a technological impact. In this paper, we investigate the impact of Al, Y, and La doping, which have experimentally proven to stabilize the ferroelectric Pca21 phase in HfO2, in a comprehensive first-principles study. Density functional theory calculations reveal the structure, formation energy, and total energy of various defects in HfO2. Most relevant are substitutional electronically compensated defects without oxygen vacancy, substitutional mixed compensated defects paired with a vacancy, and ionically compensated defect complexes containing two substitutional dopants paired with a vacancy. The ferroelectric phase is strongly favored with La and Y in the substitutional defect. The mixed compensated defect favors the ferroelectric phase as well, but the strongly favored cubic phase limits the concentration range for ferroelectricity. We conclude that a reduction of oxygen vacancies should significantly enhance this range in Y doped HfO2 thin films. With Al, the substitutional defect hardly favors the ferroelectric phase before the tetragonal phase becomes strongly favored with the increasing concentration. This could explain the observed field induced ferroelectricity in Al-doped HfO2. Further Al defects are investigated, but do not favor the f-phase such that the current explanation remains incomplete for Al doping. According to the simulation, doping alone shows clear trends, but is insufficient to replace the monoclinic phase as the ground state. To explain this fact, some other mechanism is needed.

Thermochemistry of Hydroxyl and Hydroperoxide Substituted Furan, Methylfuran, and Methoxyfuran.

PubMed

Hudzik, Jason M; Bozzelli, Joseph W

2017-06-15

Reaction pathways are influenced by thermochemical properties, species stability, and chemical kinetics. Understanding these factors allows for an understanding of the reaction paths and formation of intermediate species. Enthalpies of formation (ΔH f,298 ° ), entropies (S 298 ° ), heat capacities (C p (T)), oxygen-hydrogen (O-H), oxygen-oxygen (O-O), and (R-O) bond dissociation energies (BDEs) are reported for hydroxyl and hydroperoxide substituted furan, methylfuran, and methoxyfuran species. Standard enthalpies of formation for parent and radical species have been determined using density functional theory B3LYP/6-31G(d,p), B3LYP/6-311G(2d,2p), and M06-2X/6-31G(d,p) along with higher-level CBS-QB3 and CBS-APNO composite methods. Isodesmic work reactions were employed to improve accuracy by canceling error and show consistency between the levels of theory. Corresponding O-H and O-O BDEs are determined and compared to other similar structures. The stability of the furan moiety coupled with the double-bond-forming capability of the oxygen moiety results in a number of bond energies significantly lower than one might have expected. Substituted hydroperoxides are calculated to have ROO-H BDEs between 86.9 and 94.2 kcal mol -1 , and their RO-OH BDEs show a large 49 kcal mol -1 range of -2.3-46.8 kcal mol -1 . Substituted alcohols also show a wide 48 kcal mol -1 range with RO-H BDEs, ranging from 59.3 to 106.9 kcal mol -1 . Bond lengths of parent and radical species are presented to highlight potential bonds of interest leading to furan ring opening. Group additivity is discussed, and groups for substituted furan, methylfuran, and methoxyfuran species are derived. Structures, moments of inertia, vibrational frequencies, and internal rotor potentials are calculated at the B3LYP/6-31G(d,p) density functional level and are used to determine the S 298 ° and C p (T) values.

Effects of free sugars on blood pressure and lipids: a systematic review and meta-analysis of nutritional isoenergetic intervention trials.

PubMed

Fattore, Elena; Botta, Francesca; Agostoni, Carlo; Bosetti, Cristina

2017-01-01

Sugar has been suggested as a central risk factor in the development of noncommunicable diseases. We assessed the evidence of the effects of free sugars compared with complex carbohydrates on selected cardiovascular disease risk factors. We conducted a systematic review and meta-analysis of intervention trials to compare diets that provide a given amount of energy from free sugars with a control diet that provides the same amount of energy from complex carbohydrates. The primary outcomes were: blood pressure, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triacylglycerols, apolipoproteins A-I and B, or very low-density lipoprotein cholesterol. Body weight was also recorded but was not a primary outcome of the studies. In all, 28 studies involving 510 volunteers were included. When free sugars were substituted for complex carbohydrates, no significant increases were detected in systolic or diastolic blood pressure, and no heterogeneity was observed. There were significant increases in HDL cholesterol, LDL cholesterol, and triacylglycerols, although for LDL cholesterol and triacylglycerols there was significant heterogeneity between studies and evidence of publication bias. After adjustment for missing studies, these increases lost significance. Subgroup analyses showed that diets providing the largest total energy intake and energy exchange enhanced the effect of free sugars on total and LDL cholesterol and triacylglycerols. The increase of triacylglycerols was no longer significant when studies with the highest risk of bias were excluded or when only randomized trials were considered. Free sugars had no effect on body weight. In short- or moderate-term isoenergetic intervention trials, the substitution of free sugars for complex carbohydrates had no effect on blood pressure or body weight and an unclear effect on blood lipid profile. Further independent trials are required to assess whether the reduction of free sugars improves cardiovascular disease risk factors. This review was registered at http://www.crd.york.ac.uk/prospero as CRD42016042930. © 2017 American Society for Nutrition.

Enhanced bioactivity, biocompatibility and mechanical behavior of strontium substituted bioactive glasses.

PubMed

Arepalli, Sampath Kumar; Tripathi, Himanshu; Hira, Sumit Kumar; Manna, Partha Pratim; Pyare, Ram; S P Singh

2016-12-01

Strontium contained biomaterials have been reported as a potential bioactive material for bone regeneration, as it reduces bone resorption and stimulates bone formation. In the present investigation, the bioactive glasses were designed to partially substitute SrO for SiO2 in Na2O-CaO-SrO-P2O5-SiO2 system. This work demonstrates that the substitution of SrO for SiO2 has got significant benefit than substitution for CaO in the bioactive glass. Bioactivity was assessed by the immersion of the samples in simulated body fluid for different intervals. The formation of hydroxy carbonate apatite layer was identified by X-ray diffractometry, scanning electron microscopy (SEM) and energy dispersive spectroscopy. The elastic modulus of the bioactive glasses was measured and found to increase with increasing SrO for SiO2. The blood compatibility of the samples was evaluated. In vitro cell culture studies of the samples were performed using human osteosarcoma U2-OS cell lines and found a significant improvement in cell viability and proliferation. The investigation showed enhancement in bioactivity, mechanical and biological properties of the strontia substituted for silica in glasses. Thus, these bioactive glasses would be highly potential for bone regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.

Enhanced O 2 selectivity versus N 2 by partial metal substitution in Cu-BTC

DOE PAGES

Sava Gallis, Dorina F.; Parkes, Marie V.; Greathouse, Jeffery A.; ...

2015-03-05

Here we describe the homogeneous substitution of Mn, Fe and Co at various levels into a prototypical metal-organic framework (MOF), namely Cu-BTC (HKUST-1), and the effect of that substitution on preferential gas sorption. Using a combination of density functional theory (DFT) calculations, postsynthetic metal substitutions, materials characterization, and gas sorption testing, we demonstrate that the identity of the metal ion has a quantifiable effect on their oxygen and nitrogen sorption properties at cryogenic temperatures. An excellent correlation is found between O 2/N 2 selectivities determined experimentally at 77 K and the difference in O 2 and N 2 binding energiesmore » calculated from DFT modeling data: Mn > Fe > Co > Cu. Room temperature gas sorption studies were also performed and correlated with metal substitution. The Fe-exchanged sample shows a significantly higher nitrogen isosteric heat of adsorption at temperatures close to ambient conditions (273 K - 298 K) as compared to all other metals studied, indicative of favorable interactions between N 2 and coordinatively unsaturated Fe metal centers. Furthermore, differences in gas adsorption results at cryogenic and room temperatures are evident; they are explained by comparing experimental results with DFT binding energies (0 K) and room temperature Grand Canonical Monte Carlo simulations.« less

Melissa Hudman | NREL

Science.gov Websites

Melissa Hudman Photo of Melissa Hudman Melissa Hudman Professional I-Project Administrator Energy Analysis Center. Areas of Expertise Media relations Project coordination Research Interests , Colorado Serenity Magazine (2008) Substitute Teacher, Jeffco School District (2007) Media Relations

Relative contribution of combined kinetic and exchange energy terms vs the electronic component of molecular electrostatic potential in hardness potential derivatives.

PubMed

Bhattacharjee, Rituparna; Roy, Ram Kinkar

2013-11-14

The relative contribution of the sum of kinetic [(10/9)CFρ(r)2/3] and exchange energy [(4/9)CXρ(r)1/3] terms to that of the electronic part of the molecular electrostatic potential [Vel(r)] in the variants of hardness potential is investigated to assess the proposed definition of Δ+h(k) = −[VelN+1(k) – VelN(k)] and Δ–h(k) = −[VelN(k) – VelN–1(k)] (Saha; et al. J. Comput. Chem. 2013, 34, 662). Some substituted benzenes and polycyclic aromatic hydrocarbons (PAHs) (undergoing electrophilic aromatic substitution), carboxylic acids, and their derivatives are chosen to carry out the theoretical investigation as stated above. Intra- and intermolecular reactivity trends generated by Δ+h(k) and Δ–h(k) are found to be satisfactory and are correlated reasonably well with experimental results.

Enhanced hydrogen storage on Li-doped defective graphene with B substitution: A DFT study

NASA Astrophysics Data System (ADS)

Zhou, Yanan; Chu, Wei; Jing, Fangli; Zheng, Jian; Sun, Wenjing; Xue, Ying

2017-07-01

The characteristics of hydrogen adsorption on Li-doped defective graphene systems were investigated using density functional theory (DFT) calculations. Four types of defective structures were selected. Li atoms were well dispersed on the defective graphene without clustering, evidenced by the binding energy value between Li and defective graphene than that of Li-Lix. Additionally, as the amount of adsorbed H2 molecules increase, the H2 molecules show tilting configuration toward the Li adatom. This is beneficial for more hydrogen adsorption under the electrostatic interaction. On these four stable structures, there were up to three polarized H2 molecules adsorbed on per Li adatom, with the average hydrogen adsorption energy in the range of approximately 0.2-0.4 eV. These results provide new focus on the nature of Li-doped defective graphene with sometimes B substitution medium, which could be considered as a promising candidate for hydrogen storage.

AB INITIO STUDY OF GRAIN BOUNDARY PROPERTIES OF TUNGSTEN ALLOYS

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

Setyawan, Wahyu; Kurtz, Richard J.

2012-04-17

Density functional theory was employed to investigate the grain boundary (GB) property of W-TM alloys (TM: fifth and sixth row transition metals). GB strengthening was found for Hf, Ta, Nb, Ru, Re, Os and Ir for 27{l_brace}525{r_brace} and to a lesser degree for 11{l_brace}323{r_brace}. Lower valence solutes strengthen the GB at certain substitutional sites, while higher valence elements enforce it at other positions. For 3{l_brace}112{r_brace}, the alloys exhibit reduced cleavage energies. Hence, allowing with TMs increases the GB cohesion more effectively for large-angle GBs whose cleavage energy is, in general, inherently lower than the low-angle ones. Electron density analysis elucidatesmore » the mechanism of charge addition or depletion of the GB bonding region upon TM substitution at various positions leading to stronger or weaker intergranular cohesion, respectively.« less

Substituent effects on rates and torquoselectivities of electrocyclic ring-openings of N-substituted 2-azetines.

PubMed

Lopez, Steven A; Houk, K N

2014-07-03

Transition structures for the conrotatory electrocyclic ring-opening reactions of N-substituted 2-azetines were computed with the density functional M06-2X/6-31+G(d,p). A wide range of substituents from π acceptors (e.g., CHO, CN) to π donors (NMe2, OMe) was explored. Acceptor substituents delocalize the nitrogen lone pair and stabilize the reactant state of 2-azetines, while donors destabilize the 2-azetine reactant state. The conrotatory ring-opening is torquoselective, and the transition state for the outward rotation of the N-substituent and inward rotation of the nitrogen lone pair is preferred. This transition structure is stabilized by an interaction between the nitrogen lone pair and the vacant π* orbital. The activation free energies are linearly related to the reaction free energies and the Taft σR(0) parameter.

Role of Bi3+ substitution on structural, magnetic and optical properties of cobalt spinel ferrite

NASA Astrophysics Data System (ADS)

Anjum, Safia; Sehar, Fatima; Awan, M. S.; Zia, Rehana

2016-04-01

Bismuth-doped cobalt ferrite CoBi x Fe(2- x)O4 with x = 0, 0.1,0.2, 0.3, 0.4, 0.5 have been prepared using powder metallurgy route. The structural, morphological, elemental, magnetic and optical properties have been investigated using X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-rays, vibrating sample magnetometer and ultraviolet-visible spectrometer, respectively. X-ray diffractometer analysis confirms the formation of single-phase cubic spinel structure. As the substitution of larger ionic radii Bi3+ ions increases in cobalt ferrite which is responsible to increase the lattice parameters and decrease the crystallite size. SEM micrographs revealed the spherical shape of the particles with the nonuniform grain boundaries. The saturation magnetization decreases and bandgap energy increases as the concentration of non-magnetic Bi3+ ions increases.

Experimental and numerical measurements of adhesion energies between PHEMA and PGLYMA with hydroxyapatite crystal.

PubMed

Youssefian, Sina; Liu, Pingsheng; Askarinejad, Sina; Shalchy, Faezeh; Song, Jie; Rahbar, Nima

2015-07-16

Synthetic orthopaedic materials consisting of a single bioinert polymeric material do not meet the complex biological and physical requirements of scaffold-guided bone tissue repair and regeneration. Of particular interest is the design of biocompatible hydrogel-hydroxyapatite composite bone substitutes with outstanding interfacial adhesion that would warranty the ability for the composite to withstand functional loadings without exhibiting brittle fractures during the dynamic guided tissue regeneration. For this purpose, the hydroxylated side chain of chemically cross-linked poly (2-hydroxyethyl methacrylate) (pHEMA) is substitute with a carboxylated side chain to make poly (glycerol methacrylate) (pGLYMA). Here, we carry out atomistic simulations and atomic force microscopy to predict and experimentally determine the interfacial adhesion energies of pHEMA and pGLYMA with the surface of single-crystalline hydroxyapatite (HA) whiskers. Both experimental and numerical results showed that pGLYMA has stronger adhesion forces with HA and may be used for preparing a high-affinity polymer-HA composite. The high adhesive interactions between pGLYMA and HA were found to be due to strong electrostatic energies.

Ternary metal fluorides as high-energy cathodes with low cycling hysteresis

DOE PAGES

Wang, Feng; Kim, Sung -Wook; Seo, Dong -Hwa; ...

2015-03-26

In this study, transition metal fluorides are an appealing alternative to conventional intercalation compounds for use as cathodes in next-generation lithium batteries due to their extremely high capacity (3–4 times greater than the current state-of-the-art). However, issues related to reversibility, energy efficiency and kinetics prevent their practical application. Here we report on the synthesis, structural and electrochemical properties of ternary metal fluorides (M 1 yM 2 1-yF x: M 1, M 2 = Fe, Cu), which may overcome these issues. By substituting Cu into the Fe lattice, forming the solid–solution Cu yFe 1-yF 2, reversible Cu and Fe redox reactionsmore » are achieved with surprisingly small hysteresis (<150 mV). This finding indicates that cation substitution may provide a new avenue for tailoring key electrochemical properties of conversion electrodes. In conclusion, although the reversible capacity of Cu conversion fades rapidly, likely due to Cu + dissolution, the low hysteresis and high energy suggest that a Cu-based fluoride cathode remains an intriguing candidate for rechargeable lithium batteries.« less

Net radiative forcing from widespread deployment of photovoltaics.

PubMed

Nemet, Gregory F

2009-03-15

If photovoltaics (PV) are to contribute significantly to stabilizing the climate, they will need to be deployed on the scale of multiple terawatts. Installation of that much PV would cover substantial portions of the Earth's surface with dark-colored, sunlight-absorbing panels, reducing the Earth's albedo. How much radiative forcing would result from this change in land use? How does this amount compare to the radiative forcing avoided by substituting PV for fossil fuels? This analysis uses a series of simple equations to compare the two effects and finds that substitution dominates; the avoided radiative forcing due to substitution of PV for fossil fuels is approximately 30 times largerthan the forcing due to albedo modification. Sensitivity analysis, including discounting of future costs and benefits, identifies unfavorable yet plausible configurations in which the albedo effect substantially reduces the climatic benefits of PV. The value of PV as a climate mitigation option depends on how it is deployed, not just how much it is deployed--efficiency of PV systems and the carbon intensity of the substituted energy are particularly important