[Possible changes in energy-minimizer mechanisms of locomotion due to chronic low back pain - a literature review].

PubMed

de Carvalho, Alberito Rodrigo; Andrade, Alexandro; Peyré-Tartaruga, Leonardo Alexandre

2015-01-01

One goal of the locomotion is to move the body in the space at the most economical way possible. However, little is known about the mechanical and energetic aspects of locomotion that are affected by low back pain. And in case of occurring some damage, little is known about how the mechanical and energetic characteristics of the locomotion are manifested in functional activities, especially with respect to the energy-minimizer mechanisms during locomotion. This study aimed: a) to describe the main energy-minimizer mechanisms of locomotion; b) to check if there are signs of damage on the mechanical and energetic characteristics of the locomotion due to chronic low back pain (CLBP) which may endanger the energy-minimizer mechanisms. This study is characterized as a narrative literature review. The main theory that explains the minimization of energy expenditure during the locomotion is the inverted pendulum mechanism, by which the energy-minimizer mechanism converts kinetic energy into potential energy of the center of mass and vice-versa during the step. This mechanism is strongly influenced by spatio-temporal gait (locomotion) parameters such as step length and preferred walking speed, which, in turn, may be severely altered in patients with chronic low back pain. However, much remains to be understood about the effects of chronic low back pain on the individual's ability to practice an economic locomotion, because functional impairment may compromise the mechanical and energetic characteristics of this type of gait, making it more costly. Thus, there are indications that such changes may compromise the functional energy-minimizer mechanisms. Copyright © 2014 Elsevier Editora Ltda. All rights reserved.

Energy-efficient ECG compression on wireless biosensors via minimal coherence sensing and weighted ℓ₁ minimization reconstruction.

PubMed

Zhang, Jun; Gu, Zhenghui; Yu, Zhu Liang; Li, Yuanqing

2015-03-01

Low energy consumption is crucial for body area networks (BANs). In BAN-enabled ECG monitoring, the continuous monitoring entails the need of the sensor nodes to transmit a huge data to the sink node, which leads to excessive energy consumption. To reduce airtime over energy-hungry wireless links, this paper presents an energy-efficient compressed sensing (CS)-based approach for on-node ECG compression. At first, an algorithm called minimal mutual coherence pursuit is proposed to construct sparse binary measurement matrices, which can be used to encode the ECG signals with superior performance and extremely low complexity. Second, in order to minimize the data rate required for faithful reconstruction, a weighted ℓ1 minimization model is derived by exploring the multisource prior knowledge in wavelet domain. Experimental results on MIT-BIH arrhythmia database reveals that the proposed approach can obtain higher compression ratio than the state-of-the-art CS-based methods. Together with its low encoding complexity, our approach can achieve significant energy saving in both encoding process and wireless transmission.

[Can the local energy minimization refine the PDB structures of different resolution universally?].

PubMed

Godzi, M G; Gromova, A P; Oferkin, I V; Mironov, P V

2009-01-01

The local energy minimization was statistically validated as the refinement strategy for PDB structure pairs of different resolution. Thirteen pairs of structures with the only difference in resolution were extracted from PDB, and the structures of 11 identical proteins obtained by different X-ray diffraction techniques were represented. The distribution of RMSD value was calculated for these pairs before and after the local energy minimization of each structure. The MMFF94 field was used for energy calculations, and the quasi-Newton method was used for local energy minimization. By comparison of these two RMSD distributions, the local energy minimization was proved to statistically increase the structural differences in pairs so that it cannot be used for refinement purposes. To explore the prospects of complex refinement strategies based on energy minimization, randomized structures were obtained by moving the initial PDB structures as far as the minimized structures had been moved in a multidimensional space of atomic coordinates. For these randomized structures, the RMSD distribution was calculated and compared with that for minimized structures. The significant differences in their mean values proved the energy surface of the protein to have only few minima near the conformations of different resolution obtained by X-ray diffraction for PDB. Some other results obtained by exploring the energy surface near these conformations are also presented. These results are expected to be very useful for the development of new protein refinement strategies based on energy minimization.

Sculpting proteins interactively: continual energy minimization embedded in a graphical modeling system.

PubMed

Surles, M C; Richardson, J S; Richardson, D C; Brooks, F P

1994-02-01

We describe a new paradigm for modeling proteins in interactive computer graphics systems--continual maintenance of a physically valid representation, combined with direct user control and visualization. This is achieved by a fast algorithm for energy minimization, capable of real-time performance on all atoms of a small protein, plus graphically specified user tugs. The modeling system, called Sculpt, rigidly constrains bond lengths, bond angles, and planar groups (similar to existing interactive modeling programs), while it applies elastic restraints to minimize the potential energy due to torsions, hydrogen bonds, and van der Waals and electrostatic interactions (similar to existing batch minimization programs), and user-specified springs. The graphical interface can show bad and/or favorable contacts, and individual energy terms can be turned on or off to determine their effects and interactions. Sculpt finds a local minimum of the total energy that satisfies all the constraints using an augmented Lagrange-multiplier method; calculation time increases only linearly with the number of atoms because the matrix of constraint gradients is sparse and banded. On a 100-MHz MIPS R4000 processor (Silicon Graphics Indigo), Sculpt achieves 11 updates per second on a 20-residue fragment and 2 updates per second on an 80-residue protein, using all atoms except non-H-bonding hydrogens, and without electrostatic interactions. Applications of Sculpt are described: to reverse the direction of bundle packing in a designed 4-helix bundle protein, to fold up a 2-stranded beta-ribbon into an approximate beta-barrel, and to design the sequence and conformation of a 30-residue peptide that mimics one partner of a protein subunit interaction. Computer models that are both interactive and physically realistic (within the limitations of a given force field) have 2 significant advantages: (1) they make feasible the modeling of very large changes (such as needed for de novo design), and

Maximizing cellulosic ethanol potentials by minimizing wastewater generation and energy consumption: Competing with corn ethanol.

PubMed

Liu, Gang; Bao, Jie

2017-12-01

Energy consumption and wastewater generation in cellulosic ethanol production are among the determinant factors on overall cost and technology penetration into fuel ethanol industry. This study analyzed the energy consumption and wastewater generation by the new biorefining process technology, dry acid pretreatment and biodetoxification (DryPB), as well as by the current mainstream technologies. DryPB minimizes the steam consumption to 8.63GJ and wastewater generation to 7.71tons in the core steps of biorefining process for production of one metric ton of ethanol, close to 7.83GJ and 8.33tons in corn ethanol production, respectively. The relatively higher electricity consumption is compensated by large electricity surplus from lignin residue combustion. The minimum ethanol selling price (MESP) by DryPB is below $2/gal and falls into the range of corn ethanol production cost. The work indicates that the technical and economical gap between cellulosic ethanol and corn ethanol has been almost filled up. Copyright © 2017 Elsevier Ltd. All rights reserved.

Free energy minimization to predict RNA secondary structures and computational RNA design.

PubMed

Churkin, Alexander; Weinbrand, Lina; Barash, Danny

2015-01-01

Determining the RNA secondary structure from sequence data by computational predictions is a long-standing problem. Its solution has been approached in two distinctive ways. If a multiple sequence alignment of a collection of homologous sequences is available, the comparative method uses phylogeny to determine conserved base pairs that are more likely to form as a result of billions of years of evolution than by chance. In the case of single sequences, recursive algorithms that compute free energy structures by using empirically derived energy parameters have been developed. This latter approach of RNA folding prediction by energy minimization is widely used to predict RNA secondary structure from sequence. For a significant number of RNA molecules, the secondary structure of the RNA molecule is indicative of its function and its computational prediction by minimizing its free energy is important for its functional analysis. A general method for free energy minimization to predict RNA secondary structures is dynamic programming, although other optimization methods have been developed as well along with empirically derived energy parameters. In this chapter, we introduce and illustrate by examples the approach of free energy minimization to predict RNA secondary structures.

Nonlinear transient analysis via energy minimization

NASA Technical Reports Server (NTRS)

Kamat, M. P.; Knight, N. F., Jr.

1978-01-01

The formulation basis for nonlinear transient analysis of finite element models of structures using energy minimization is provided. Geometric and material nonlinearities are included. The development is restricted to simple one and two dimensional finite elements which are regarded as being the basic elements for modeling full aircraft-like structures under crash conditions. The results indicate the effectiveness of the technique as a viable tool for this purpose.

Determining the electron energy distribution near the plasma potential in the earth's ionosphere

NASA Technical Reports Server (NTRS)

Sharp, W. E.; Hays, P. B.; Cutler, J. R.; Dobbs, M. E.

1981-01-01

A determination of the plasma potential using an electrostatic analyzer is described in which the potential difference between the instrument slit system and surrounding plasma is minimized. Data obtained from rocket-borne instrumentation demonstrate the viability of this technique for electron fluxes between thermal energies (about 0.5 V) and suprathermal energies (many volts).

Minimizing energy dissipation of matrix multiplication kernel on Virtex-II

NASA Astrophysics Data System (ADS)

Choi, Seonil; Prasanna, Viktor K.; Jang, Ju-wook

2002-07-01

In this paper, we develop energy-efficient designs for matrix multiplication on FPGAs. To analyze the energy dissipation, we develop a high-level model using domain-specific modeling techniques. In this model, we identify architecture parameters that significantly affect the total energy (system-wide energy) dissipation. Then, we explore design trade-offs by varying these parameters to minimize the system-wide energy. For matrix multiplication, we consider a uniprocessor architecture and a linear array architecture to develop energy-efficient designs. For the uniprocessor architecture, the cache size is a parameter that affects the I/O complexity and the system-wide energy. For the linear array architecture, the amount of storage per processing element is a parameter affecting the system-wide energy. By using maximum amount of storage per processing element and minimum number of multipliers, we obtain a design that minimizes the system-wide energy. We develop several energy-efficient designs for matrix multiplication. For example, for 6×6 matrix multiplication, energy savings of upto 52% for the uniprocessor architecture and 36% for the linear arrary architecture is achieved over an optimized library for Virtex-II FPGA from Xilinx.

Smart HVAC Control in IoT: Energy Consumption Minimization with User Comfort Constraints

PubMed Central

Verikoukis, Christos

2014-01-01

Smart grid is one of the main applications of the Internet of Things (IoT) paradigm. Within this context, this paper addresses the efficient energy consumption management of heating, ventilation, and air conditioning (HVAC) systems in smart grids with variable energy price. To that end, first, we propose an energy scheduling method that minimizes the energy consumption cost for a particular time interval, taking into account the energy price and a set of comfort constraints, that is, a range of temperatures according to user's preferences for a given room. Then, we propose an energy scheduler where the user may select to relax the temperature constraints to save more energy. Moreover, thanks to the IoT paradigm, the user may interact remotely with the HVAC control system. In particular, the user may decide remotely the temperature of comfort, while the temperature and energy consumption information is sent through Internet and displayed at the end user's device. The proposed algorithms have been implemented in a real testbed, highlighting the potential gains that can be achieved in terms of both energy and cost. PMID:25054163

Smart HVAC control in IoT: energy consumption minimization with user comfort constraints.

PubMed

Serra, Jordi; Pubill, David; Antonopoulos, Angelos; Verikoukis, Christos

2014-01-01

Smart grid is one of the main applications of the Internet of Things (IoT) paradigm. Within this context, this paper addresses the efficient energy consumption management of heating, ventilation, and air conditioning (HVAC) systems in smart grids with variable energy price. To that end, first, we propose an energy scheduling method that minimizes the energy consumption cost for a particular time interval, taking into account the energy price and a set of comfort constraints, that is, a range of temperatures according to user's preferences for a given room. Then, we propose an energy scheduler where the user may select to relax the temperature constraints to save more energy. Moreover, thanks to the IoT paradigm, the user may interact remotely with the HVAC control system. In particular, the user may decide remotely the temperature of comfort, while the temperature and energy consumption information is sent through Internet and displayed at the end user's device. The proposed algorithms have been implemented in a real testbed, highlighting the potential gains that can be achieved in terms of both energy and cost.

Quantum scattering in one-dimensional systems satisfying the minimal length uncertainty relation

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

Bernardo, Reginald Christian S., E-mail: rcbernardo@nip.upd.edu.ph; Esguerra, Jose Perico H., E-mail: jesguerra@nip.upd.edu.ph

In quantum gravity theories, when the scattering energy is comparable to the Planck energy the Heisenberg uncertainty principle breaks down and is replaced by the minimal length uncertainty relation. In this paper, the consequences of the minimal length uncertainty relation on one-dimensional quantum scattering are studied using an approach involving a recently proposed second-order differential equation. An exact analytical expression for the tunneling probability through a locally-periodic rectangular potential barrier system is obtained. Results show that the existence of a non-zero minimal length uncertainty tends to shift the resonant tunneling energies to the positive direction. Scattering through a locally-periodic potentialmore » composed of double-rectangular potential barriers shows that the first band of resonant tunneling energies widens for minimal length cases when the double-rectangular potential barrier is symmetric but narrows down when the double-rectangular potential barrier is asymmetric. A numerical solution which exploits the use of Wronskians is used to calculate the transmission probabilities through the Pöschl–Teller well, Gaussian barrier, and double-Gaussian barrier. Results show that the probability of passage through the Pöschl–Teller well and Gaussian barrier is smaller in the minimal length cases compared to the non-minimal length case. For the double-Gaussian barrier, the probability of passage for energies that are more positive than the resonant tunneling energy is larger in the minimal length cases compared to the non-minimal length case. The approach is exact and applicable to many types of scattering potential.« less

Minimizing Higgs potentials via numerical polynomial homotopy continuation

NASA Astrophysics Data System (ADS)

Maniatis, M.; Mehta, D.

2012-08-01

The study of models with extended Higgs sectors requires to minimize the corresponding Higgs potentials, which is in general very difficult. Here, we apply a recently developed method, called numerical polynomial homotopy continuation (NPHC), which guarantees to find all the stationary points of the Higgs potentials with polynomial-like non-linearity. The detection of all stationary points reveals the structure of the potential with maxima, metastable minima, saddle points besides the global minimum. We apply the NPHC method to the most general Higgs potential having two complex Higgs-boson doublets and up to five real Higgs-boson singlets. Moreover the method is applicable to even more involved potentials. Hence the NPHC method allows to go far beyond the limits of the Gröbner basis approach.

Running non-minimal inflation with stabilized inflaton potential

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

Okada, Nobuchika; Raut, Digesh

In the context of the Higgs model involving gauge and Yukawa interactions with the spontaneous gauge symmetry breaking, we consider λφ4 inflation with non- minimal gravitational coupling, where the Higgs field is identified as the inflaton. Since the inflaton quartic coupling is very small, once quantum corrections through the gauge and Yukawa interactions are taken into account, the inflaton effective potential most likely becomes unstable. Furthermore, in order to avoid this problem, we need to impose stability conditions on the effective inflaton potential, which lead to not only non-trivial relations amongst the particle mass spectrum of the model, but alsomore » correlations between the inflationary predictions and the mass spectrum. For reasons of concrete discussion, we investigate the minimal B - L extension of the standard model with identification of the B - L Higgs field as the inflaton. The stability conditions for the inflaton effective potential fix the mass ratio amongst the B - L gauge boson, the right-handed neutrinos and the inflaton. This mass ratio also correlates with the inflationary predictions. So, if the B - L gauge boson and the right-handed neutrinos are discovered in the future, their observed mass ratio provides constraints on the inflationary predictions.« less

Running non-minimal inflation with stabilized inflaton potential

DOE PAGES

Okada, Nobuchika; Raut, Digesh

2017-04-18

In the context of the Higgs model involving gauge and Yukawa interactions with the spontaneous gauge symmetry breaking, we consider λφ4 inflation with non- minimal gravitational coupling, where the Higgs field is identified as the inflaton. Since the inflaton quartic coupling is very small, once quantum corrections through the gauge and Yukawa interactions are taken into account, the inflaton effective potential most likely becomes unstable. Furthermore, in order to avoid this problem, we need to impose stability conditions on the effective inflaton potential, which lead to not only non-trivial relations amongst the particle mass spectrum of the model, but alsomore » correlations between the inflationary predictions and the mass spectrum. For reasons of concrete discussion, we investigate the minimal B - L extension of the standard model with identification of the B - L Higgs field as the inflaton. The stability conditions for the inflaton effective potential fix the mass ratio amongst the B - L gauge boson, the right-handed neutrinos and the inflaton. This mass ratio also correlates with the inflationary predictions. So, if the B - L gauge boson and the right-handed neutrinos are discovered in the future, their observed mass ratio provides constraints on the inflationary predictions.« less

Minimal nuclear energy density functional

NASA Astrophysics Data System (ADS)

Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi; Perez, Rodrigo Navarro; Schunck, Nicolas

2018-04-01

We present a minimal nuclear energy density functional (NEDF) called "SeaLL1" that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ɛr=0.022 fm and a standard deviation σr=0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body (NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body (NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. We identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.

Minimal nuclear energy density functional

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

Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi

Inmore » this paper, we present a minimal nuclear energy density functional (NEDF) called “SeaLL1” that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ε r = 0.022 fm and a standard deviation σ r = 0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body ( NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body ( NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. Finally, we identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.« less

Minimal nuclear energy density functional

DOE PAGES

Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi; ...

2018-04-17

Inmore » this paper, we present a minimal nuclear energy density functional (NEDF) called “SeaLL1” that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ε r = 0.022 fm and a standard deviation σ r = 0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body ( NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body ( NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. Finally, we identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.« less

Stability analysis for non-minimally coupled dark energy models in the Palatini formalism

NASA Astrophysics Data System (ADS)

Wang, Zuobin; Wu, Puxun; Yu, Hongwei

2018-06-01

In this paper, we use the method of global analysis to study the stability of de-Sitter solutions in an universe dominated by a scalar field dark energy, which couples non-minimally with the Ricci scalar defined in the Palatini formalism. Effective potential and phase-space diagrams are introduced to describe qualitatively the de-Sitter solutions and their stabilities. We find that for the simple power-law function V(φ)=V0φn there are no stable de-Sitter solutions. While for some more complicated potentials, i.e. V(φ)=V0φn+Λ and V(φ)=V0 (e ^{-λφ}+e^{λφ)2, stable de-Sitter solutions can exist.

Consolidation of hydrophobic transition criteria by using an approximate energy minimization approach.

PubMed

Patankar, Neelesh A

2010-06-01

Recent experimental work has successfully revealed pressure induced transition from Cassie to Wenzel state on rough hydrophobic substrates. Formulas, based on geometric considerations and imposed pressure, have been developed as transition criteria. In the past, transition has also been considered as a process of overcoming the energy barrier between the Cassie and Wenzel states. A unified understanding of the various considerations of transition has not been apparent. To address this issue, in this work, we consolidate the transition criteria with a homogenized energy minimization approach. This approach decouples the problem of minimizing the energy to wet the rough substrate, from the energy of the macroscopic drop. It is seen that the transition from Cassie to Wenzel state, due to depinning of the liquid-air interface, emerges from the approximate energy minimization approach if the pressure-volume energy associated with the impaled liquid in the roughness is included. This transition can be viewed as a process in which the work done by the pressure force is greater than the barrier due to the surface energy associated with wetting the roughness. It is argued that another transition mechanism, due to a sagging liquid-air interface that touches the bottom of the roughness grooves, is not typically relevant if the substrate roughness is designed such that the Cassie state is at lower energy compared to the Wenzel state.

Communication: Fitting potential energy surfaces with fundamental invariant neural network

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

Shao, Kejie; Chen, Jun; Zhao, Zhiqiang

A more flexible neural network (NN) method using the fundamental invariants (FIs) as the input vector is proposed in the construction of potential energy surfaces for molecular systems involving identical atoms. Mathematically, FIs finitely generate the permutation invariant polynomial (PIP) ring. In combination with NN, fundamental invariant neural network (FI-NN) can approximate any function to arbitrary accuracy. Because FI-NN minimizes the size of input permutation invariant polynomials, it can efficiently reduce the evaluation time of potential energy, in particular for polyatomic systems. In this work, we provide the FIs for all possible molecular systems up to five atoms. Potential energymore » surfaces for OH{sub 3} and CH{sub 4} were constructed with FI-NN, with the accuracy confirmed by full-dimensional quantum dynamic scattering and bound state calculations.« less

Regional prediction of long-term landfill gas to energy potential.

PubMed

Amini, Hamid R; Reinhart, Debra R

2011-01-01

Quantifying landfill gas to energy (LFGTE) potential as a source of renewable energy is difficult due to the challenges involved in modeling landfill gas (LFG) generation. In this paper a methodology is presented to estimate LFGTE potential on a regional scale over a 25-year timeframe with consideration of modeling uncertainties. The methodology was demonstrated for the US state of Florida, as a case study, and showed that Florida could increase the annual LFGTE production by more than threefold by 2035 through installation of LFGTE facilities at all landfills. The estimated electricity production potential from Florida LFG is equivalent to removing some 70 million vehicles from highways or replacing over 800 million barrels of oil consumption during the 2010-2035 timeframe. Diverting food waste could significantly reduce fugitive LFG emissions, while having minimal effect on the LFGTE potential; whereas, achieving high diversion goals through increased recycling will result in reduced uncollected LFG and significant loss of energy production potential which may be offset by energy savings from material recovery and reuse. Estimates showed that the power density for Florida LFGTE production could reach as high as 10 Wm(-2) with optimized landfill operation and energy production practices. The environmental benefits from increased lifetime LFG collection efficiencies magnify the value of LFGTE projects. Copyright © 2011 Elsevier Ltd. All rights reserved.

A strategy to minimize the energy offset in carrier injection from excited dyes to inorganic semiconductors for efficient dye-sensitized solar energy conversion.

PubMed

Fujisawa, Jun-Ichi; Osawa, Ayumi; Hanaya, Minoru

2016-08-10

Photoinduced carrier injection from dyes to inorganic semiconductors is a crucial process in various dye-sensitized solar energy conversions such as photovoltaics and photocatalysis. It has been reported that an energy offset larger than 0.2-0.3 eV (threshold value) is required for efficient electron injection from excited dyes to metal-oxide semiconductors such as titanium dioxide (TiO2). Because the energy offset directly causes loss in the potential of injected electrons, it is a crucial issue to minimize the energy offset for efficient solar energy conversions. However, a fundamental understanding of the energy offset, especially the threshold value, has not been obtained yet. In this paper, we report the origin of the threshold value of the energy offset, solving the long-standing questions of why such a large energy offset is necessary for the electron injection and which factors govern the threshold value, and suggest a strategy to minimize the threshold value. The threshold value is determined by the sum of two reorganization energies in one-electron reduction of semiconductors and typically-used donor-acceptor (D-A) dyes. In fact, the estimated values (0.21-0.31 eV) for several D-A dyes are in good agreement with the threshold value, supporting our conclusion. In addition, our results reveal that the threshold value is possible to be reduced by enlarging the π-conjugated system of the acceptor moiety in dyes and enhancing its structural rigidity. Furthermore, we extend the analysis to hole injection from excited dyes to semiconductors. In this case, the threshold value is given by the sum of two reorganization energies in one-electron oxidation of semiconductors and D-A dyes.

Time versus energy minimization migration strategy varies with body size and season in long-distance migratory shorebirds.

PubMed

Zhao, Meijuan; Christie, Maureen; Coleman, Jonathan; Hassell, Chris; Gosbell, Ken; Lisovski, Simeon; Minton, Clive; Klaassen, Marcel

2017-01-01

Migrants have been hypothesised to use different migration strategies between seasons: a time-minimization strategy during their pre-breeding migration towards the breeding grounds and an energy-minimization strategy during their post-breeding migration towards the wintering grounds. Besides season, we propose body size as a key factor in shaping migratory behaviour. Specifically, given that body size is expected to correlate negatively with maximum migration speed and that large birds tend to use more time to complete their annual life-history events (such as moult, breeding and migration), we hypothesise that large-sized species are time stressed all year round. Consequently, large birds are not only likely to adopt a time-minimization strategy during pre-breeding migration, but also during post-breeding migration, to guarantee a timely arrival at both the non-breeding (i.e. wintering) and breeding grounds. We tested this idea using individual tracks across six long-distance migratory shorebird species (family Scolopacidae) along the East Asian-Australasian Flyway varying in size from 50 g to 750 g lean body mass. Migration performance was compared between pre- and post-breeding migration using four quantifiable migratory behaviours that serve to distinguish between a time- and energy-minimization strategy, including migration speed, number of staging sites, total migration distance and step length from one site to the next. During pre- and post-breeding migration, the shorebirds generally covered similar distances, but they tended to migrate faster, used fewer staging sites, and tended to use longer step lengths during pre-breeding migration. These seasonal differences are consistent with the prediction that a time-minimization strategy is used during pre-breeding migration, whereas an energy-minimization strategy is used during post-breeding migration. However, there was also a tendency for the seasonal difference in migration speed to progressively disappear

Energy minimization in medical image analysis: Methodologies and applications.

PubMed

Zhao, Feng; Xie, Xianghua

2016-02-01

Energy minimization is of particular interest in medical image analysis. In the past two decades, a variety of optimization schemes have been developed. In this paper, we present a comprehensive survey of the state-of-the-art optimization approaches. These algorithms are mainly classified into two categories: continuous method and discrete method. The former includes Newton-Raphson method, gradient descent method, conjugate gradient method, proximal gradient method, coordinate descent method, and genetic algorithm-based method, while the latter covers graph cuts method, belief propagation method, tree-reweighted message passing method, linear programming method, maximum margin learning method, simulated annealing method, and iterated conditional modes method. We also discuss the minimal surface method, primal-dual method, and the multi-objective optimization method. In addition, we review several comparative studies that evaluate the performance of different minimization techniques in terms of accuracy, efficiency, or complexity. These optimization techniques are widely used in many medical applications, for example, image segmentation, registration, reconstruction, motion tracking, and compressed sensing. We thus give an overview on those applications as well. Copyright © 2015 John Wiley & Sons, Ltd.

Free-energy minimization and the dark-room problem.

PubMed

Friston, Karl; Thornton, Christopher; Clark, Andy

2012-01-01

Recent years have seen the emergence of an important new fundamental theory of brain function. This theory brings information-theoretic, Bayesian, neuroscientific, and machine learning approaches into a single framework whose overarching principle is the minimization of surprise (or, equivalently, the maximization of expectation). The most comprehensive such treatment is the "free-energy minimization" formulation due to Karl Friston (see e.g., Friston and Stephan, 2007; Friston, 2010a,b - see also Fiorillo, 2010; Thornton, 2010). A recurrent puzzle raised by critics of these models is that biological systems do not seem to avoid surprises. We do not simply seek a dark, unchanging chamber, and stay there. This is the "Dark-Room Problem." Here, we describe the problem and further unpack the issues to which it speaks. Using the same format as the prolog of Eddington's Space, Time, and Gravitation (Eddington, 1920) we present our discussion as a conversation between: an information theorist (Thornton), a physicist (Friston), and a philosopher (Clark).

New insights gained on mechanisms of low-energy proton-induced SEUs by minimizing energy straggle

DOE PAGES

Dodds, Nathaniel Anson; Dodd, Paul E.; Shaneyfelt, Marty R.; ...

2015-12-01

In this study, we present low-energy proton single-event upset (SEU) data on a 65 nm SOI SRAM whose substrate has been completely removed. Since the protons only had to penetrate a very thin buried oxide layer, these measurements were affected by far less energy loss, energy straggle, flux attrition, and angular scattering than previous datasets. The minimization of these common sources of experimental interference allows more direct interpretation of the data and deeper insight into SEU mechanisms. The results show a strong angular dependence, demonstrate that energy straggle, flux attrition, and angular scattering affect the measured SEU cross sections, andmore » prove that proton direct ionization is the dominant mechanism for low-energy proton-induced SEUs in these circuits.« less

Improved bounds on the energy-minimizing strains in martensitic polycrystals

NASA Astrophysics Data System (ADS)

Peigney, Michaël

2016-07-01

This paper is concerned with the theoretical prediction of the energy-minimizing (or recoverable) strains in martensitic polycrystals, considering a nonlinear elasticity model of phase transformation at finite strains. The main results are some rigorous upper bounds on the set of energy-minimizing strains. Those bounds depend on the polycrystalline texture through the volume fractions of the different orientations. The simplest form of the bounds presented is obtained by combining recent results for single crystals with a homogenization approach proposed previously for martensitic polycrystals. However, the polycrystalline bound delivered by that procedure may fail to recover the monocrystalline bound in the homogeneous limit, as is demonstrated in this paper by considering an example related to tetragonal martensite. This motivates the development of a more detailed analysis, leading to improved polycrystalline bounds that are notably consistent with results for single crystals in the homogeneous limit. A two-orientation polycrystal of tetragonal martensite is studied as an illustration. In that case, analytical expressions of the upper bounds are derived and the results are compared with lower bounds obtained by considering laminate textures.

Mechanical behavior of cells in microinjection: a minimum potential energy study.

PubMed

Liu, Fei; Wu, Dan; Chen, Ken

2013-08-01

Microinjection is a widely used technique to deliver foreign materials into biological cells. We propose a mathematical model to study the mechanical behavior of a cell in microinjection. Firstly, a cell is modeled by a hyperelastic membrane and interior cytoplasm. Then, based on the fact that the equilibrium configuration of a cell would minimize the potential energy, the energy function during microinjection is analyzed. With Lagrange multiplier and Rayleigh-Ritz technique, we successfully minimize the potential energy and obtain the equilibrium configuration. Upon this model, the injection force, the injection distance, the radius of the microinjector and the membrane stress are studied. The analysis demonstrates that the microinjector radius has a significant influence on the cell mechanical behavior: (1) the larger radius generates larger injection force and larger interior pressure at the same injection distance; (2) the radius determines the place where the membrane is most likely to rupture by governing the membrane stress distribution. For a fine microinjector with radius less than 20% of the cell radius, the most likely rupture point located at the edge of the contact area between the microinjector and the membrane; however, it may move to the middle of the equilibrium configuration as the radius increases. To verify our model, some experiments were conducted on zebrafish egg cells. The results show that the computational analysis agrees with the experimental data, which supports the findings from the theoretical model. Copyright © 2013 Elsevier Ltd. All rights reserved.

Minimization of a free-energy-like potential for non-equilibrium flow systems at steady state

PubMed Central

Niven, Robert K.

2010-01-01

This study examines a new formulation of non-equilibrium thermodynamics, which gives a conditional derivation of the ‘maximum entropy production’ (MEP) principle for flow and/or chemical reaction systems at steady state. The analysis uses a dimensionless potential function ϕst for non-equilibrium systems, analogous to the free energy concept of equilibrium thermodynamics. Spontaneous reductions in ϕst arise from increases in the ‘flux entropy’ of the system—a measure of the variability of the fluxes—or in the local entropy production; conditionally, depending on the behaviour of the flux entropy, the formulation reduces to the MEP principle. The inferred steady state is also shown to exhibit high variability in its instantaneous fluxes and rates, consistent with the observed behaviour of turbulent fluid flow, heat convection and biological systems; one consequence is the coexistence of energy producers and consumers in ecological systems. The different paths for attaining steady state are also classified. PMID:20368250

Inference with minimal Gibbs free energy in information field theory.

PubMed

Ensslin, Torsten A; Weig, Cornelius

2010-11-01

Non-linear and non-gaussian signal inference problems are difficult to tackle. Renormalization techniques permit us to construct good estimators for the posterior signal mean within information field theory (IFT), but the approximations and assumptions made are not very obvious. Here we introduce the simple concept of minimal Gibbs free energy to IFT, and show that previous renormalization results emerge naturally. They can be understood as being the gaussian approximation to the full posterior probability, which has maximal cross information with it. We derive optimized estimators for three applications, to illustrate the usage of the framework: (i) reconstruction of a log-normal signal from poissonian data with background counts and point spread function, as it is needed for gamma ray astronomy and for cosmography using photometric galaxy redshifts, (ii) inference of a gaussian signal with unknown spectrum, and (iii) inference of a poissonian log-normal signal with unknown spectrum, the combination of (i) and (ii). Finally we explain how gaussian knowledge states constructed by the minimal Gibbs free energy principle at different temperatures can be combined into a more accurate surrogate of the non-gaussian posterior.

On the Duffin-Kemmer-Petiau equation with linear potential in the presence of a minimal length

NASA Astrophysics Data System (ADS)

Chargui, Yassine

2018-04-01

We point out an erroneous handling in the literature regarding solutions of the (1 + 1)-dimensional Duffin-Kemmer-Petiau equation with linear potentials in the context of quantum mechanics with minimal length. Furthermore, using Brau's approach, we present a perturbative treatment of the effect of the minimal length on bound-state solutions when a Lorentz-scalar linear potential is applied.

Wormholes minimally violating the null energy condition

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

Bouhmadi-López, Mariam; Lobo, Francisco S N; Martín-Moruno, Prado, E-mail: mariam.bouhmadi@ehu.es, E-mail: fslobo@fc.ul.pt, E-mail: pmmoruno@fc.ul.pt

2014-11-01

We consider novel wormhole solutions supported by a matter content that minimally violates the null energy condition. More specifically, we consider an equation of state in which the sum of the energy density and radial pressure is proportional to a constant with a value smaller than that of the inverse area characterising the system, i.e., the area of the wormhole mouth. This approach is motivated by a recently proposed cosmological event, denoted {sup t}he little sibling of the big rip{sup ,} where the Hubble rate and the scale factor blow up but the cosmic derivative of the Hubble rate doesmore » not [1]. By using the cut-and-paste approach, we match interior spherically symmetric wormhole solutions to an exterior Schwarzschild geometry, and analyse the stability of the thin-shell to linearized spherically symmetric perturbations around static solutions, by choosing suitable properties for the exotic material residing on the junction interface radius. Furthermore, we also consider an inhomogeneous generalization of the equation of state considered above and analyse the respective stability regions. In particular, we obtain a specific wormhole solution with an asymptotic behaviour corresponding to a global monopole.« less

Finite-element grid improvement by minimization of stiffness matrix trace

NASA Technical Reports Server (NTRS)

Kittur, Madan G.; Huston, Ronald L.; Oswald, Fred B.

1989-01-01

A new and simple method of finite-element grid improvement is presented. The objective is to improve the accuracy of the analysis. The procedure is based on a minimization of the trace of the stiffness matrix. For a broad class of problems this minimization is seen to be equivalent to minimizing the potential energy. The method is illustrated with the classical tapered bar problem examined earlier by Prager and Masur. Identical results are obtained.

Finite-element grid improvement by minimization of stiffness matrix trace

NASA Technical Reports Server (NTRS)

Kittur, Madan G.; Huston, Ronald L.; Oswald, Fred B.

1987-01-01

A new and simple method of finite-element grid improvement is presented. The objective is to improve the accuracy of the analysis. The procedure is based on a minimization of the trace of the stiffness matrix. For a broad class of problems this minimization is seen to be equivalent to minimizing the potential energy. The method is illustrated with the classical tapered bar problem examined earlier by Prager and Masur. Identical results are obtained.

Beyond Group: Multiple Person Tracking via Minimal Topology-Energy-Variation.

PubMed

Gao, Shan; Ye, Qixiang; Xing, Junliang; Kuijper, Arjan; Han, Zhenjun; Jiao, Jianbin; Ji, Xiangyang

2017-12-01

Tracking multiple persons is a challenging task when persons move in groups and occlude each other. Existing group-based methods have extensively investigated how to make group division more accurately in a tracking-by-detection framework; however, few of them quantify the group dynamics from the perspective of targets' spatial topology or consider the group in a dynamic view. Inspired by the sociological properties of pedestrians, we propose a novel socio-topology model with a topology-energy function to factor the group dynamics of moving persons and groups. In this model, minimizing the topology-energy-variance in a two-level energy form is expected to produce smooth topology transitions, stable group tracking, and accurate target association. To search for the strong minimum in energy variation, we design the discrete group-tracklet jump moves embedded in the gradient descent method, which ensures that the moves reduce the energy variation of group and trajectory alternately in the varying topology dimension. Experimental results on both RGB and RGB-D data sets show the superiority of our proposed model for multiple person tracking in crowd scenes.

Minimizing the Free Energy: A Computer Method for Teaching Chemical Equilibrium Concepts.

ERIC Educational Resources Information Center

Heald, Emerson F.

1978-01-01

Presents a computer method for teaching chemical equilibrium concepts using material balance conditions and the minimization of the free energy. Method for the calculation of chemical equilibrium, the computer program used to solve equilibrium problems and applications of the method are also included. (HM)

Evolved Minimal Frustration in Multifunctional Biomolecules.

PubMed

Röder, Konstantin; Wales, David J

2018-05-25

Protein folding is often viewed in terms of a funnelled potential or free energy landscape. A variety of experiments now indicate the existence of multifunnel landscapes, associated with multifunctional biomolecules. Here, we present evidence that these systems have evolved to exhibit the minimal number of funnels required to fulfil their cellular functions, suggesting an extension to the principle of minimum frustration. We find that minimal disruptive mutations result in additional funnels, and the associated structural ensembles become more diverse. The same trends are observed in an atomic cluster. These observations suggest guidelines for rational design of engineered multifunctional biomolecules.

Flattening the inflaton potential beyond minimal gravity

NASA Astrophysics Data System (ADS)

Lee, Hyun Min

2018-01-01

We review the status of the Starobinsky-like models for inflation beyond minimal gravity and discuss the unitarity problem due to the presence of a large non-minimal gravity coupling. We show that the induced gravity models allow for a self-consistent description of inflation and discuss the implications of the inflaton couplings to the Higgs field in the Standard Model.

Energy Minimization of Molecular Features Observed on the (110) Face of Lysozyme Crystals

NASA Technical Reports Server (NTRS)

Perozzo, Mary A.; Konnert, John H.; Li, Huayu; Nadarajah, Arunan; Pusey, Marc

1999-01-01

Molecular dynamics and energy minimization have been carried out using the program XPLOR to check the plausibility of a model lysozyme crystal surface. The molecular features of the (110) face of lysozyme were observed using atomic force microscopy (AFM). A model of the crystal surface was constructed using the PDB file 193L, and was used to simulate an AFM image. Molecule translations, van der Waals radii, and assumed AFM tip shape were adjusted to maximize the correlation coefficient between the experimental and simulated images. The highest degree of 0 correlation (0.92) was obtained with the molecules displaced over 6 A from their positions within the bulk of the crystal. The quality of this starting model, the extent of energy minimization, and the correlation coefficient between the final model and the experimental data will be discussed.

Transformation of general binary MRF minimization to the first-order case.

PubMed

Ishikawa, Hiroshi

2011-06-01

We introduce a transformation of general higher-order Markov random field with binary labels into a first-order one that has the same minima as the original. Moreover, we formalize a framework for approximately minimizing higher-order multi-label MRF energies that combines the new reduction with the fusion-move and QPBO algorithms. While many computer vision problems today are formulated as energy minimization problems, they have mostly been limited to using first-order energies, which consist of unary and pairwise clique potentials, with a few exceptions that consider triples. This is because of the lack of efficient algorithms to optimize energies with higher-order interactions. Our algorithm challenges this restriction that limits the representational power of the models so that higher-order energies can be used to capture the rich statistics of natural scenes. We also show that some minimization methods can be considered special cases of the present framework, as well as comparing the new method experimentally with other such techniques.

Catching the right wave: evaluating wave energy resources and potential compatibility with existing marine and coastal uses.

PubMed

Kim, Choong-Ki; Toft, Jodie E; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D; Ruckelshaus, Marry H; Arkema, Katie K; Guannel, Gregory; Wood, Spencer A; Bernhardt, Joanna R; Tallis, Heather; Plummer, Mark L; Halpern, Benjamin S; Pinsky, Malin L; Beck, Michael W; Chan, Francis; Chan, Kai M A; Levin, Phil S; Polasky, Stephen

2012-01-01

Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses.

Catching the Right Wave: Evaluating Wave Energy Resources and Potential Compatibility with Existing Marine and Coastal Uses

PubMed Central

Kim, Choong-Ki; Toft, Jodie E.; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D.; Ruckelshaus, Marry H.; Arkema, Katie K.; Guannel, Gregory; Wood, Spencer A.; Bernhardt, Joanna R.; Tallis, Heather; Plummer, Mark L.; Halpern, Benjamin S.; Pinsky, Malin L.; Beck, Michael W.; Chan, Francis; Chan, Kai M. A.; Levin, Phil S.; Polasky, Stephen

2012-01-01

Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses. PMID:23144824

Real-space finite-difference approach for multi-body systems: path-integral renormalization group method and direct energy minimization method.

PubMed

Sasaki, Akira; Kojo, Masashi; Hirose, Kikuji; Goto, Hidekazu

2011-11-02

The path-integral renormalization group and direct energy minimization method of practical first-principles electronic structure calculations for multi-body systems within the framework of the real-space finite-difference scheme are introduced. These two methods can handle higher dimensional systems with consideration of the correlation effect. Furthermore, they can be easily extended to the multicomponent quantum systems which contain more than two kinds of quantum particles. The key to the present methods is employing linear combinations of nonorthogonal Slater determinants (SDs) as multi-body wavefunctions. As one of the noticeable results, the same accuracy as the variational Monte Carlo method is achieved with a few SDs. This enables us to study the entire ground state consisting of electrons and nuclei without the need to use the Born-Oppenheimer approximation. Recent activities on methodological developments aiming towards practical calculations such as the implementation of auxiliary field for Coulombic interaction, the treatment of the kinetic operator in imaginary-time evolutions, the time-saving double-grid technique for bare-Coulomb atomic potentials and the optimization scheme for minimizing the total-energy functional are also introduced. As test examples, the total energy of the hydrogen molecule, the atomic configuration of the methylene and the electronic structures of two-dimensional quantum dots are calculated, and the accuracy, availability and possibility of the present methods are demonstrated.

Computational methods for reactive transport modeling: A Gibbs energy minimization approach for multiphase equilibrium calculations

NASA Astrophysics Data System (ADS)

Leal, Allan M. M.; Kulik, Dmitrii A.; Kosakowski, Georg

2016-02-01

We present a numerical method for multiphase chemical equilibrium calculations based on a Gibbs energy minimization approach. The method can accurately and efficiently determine the stable phase assemblage at equilibrium independently of the type of phases and species that constitute the chemical system. We have successfully applied our chemical equilibrium algorithm in reactive transport simulations to demonstrate its effective use in computationally intensive applications. We used FEniCS to solve the governing partial differential equations of mass transport in porous media using finite element methods in unstructured meshes. Our equilibrium calculations were benchmarked with GEMS3K, the numerical kernel of the geochemical package GEMS. This allowed us to compare our results with a well-established Gibbs energy minimization algorithm, as well as their performance on every mesh node, at every time step of the transport simulation. The benchmark shows that our novel chemical equilibrium algorithm is accurate, robust, and efficient for reactive transport applications, and it is an improvement over the Gibbs energy minimization algorithm used in GEMS3K. The proposed chemical equilibrium method has been implemented in Reaktoro, a unified framework for modeling chemically reactive systems, which is now used as an alternative numerical kernel of GEMS.

Free Energy Minimization Calculation of Complex Chemical Equilibria. Reduction of Silicon Dioxide with Carbon at High Temperature.

ERIC Educational Resources Information Center

Wai, C. M.; Hutchinson, S. G.

1989-01-01

Discusses the calculation of free energy in reactions between silicon dioxide and carbon. Describes several computer programs for calculating the free energy minimization and their uses in chemistry classrooms. Lists 16 references. (YP)

Methods for finding transition states on reduced potential energy surfaces

NASA Astrophysics Data System (ADS)

Burger, Steven K.; Ayers, Paul W.

2010-06-01

Three new algorithms are presented for determining transition state (TS) structures on the reduced potential energy surface, that is, for problems in which a few important degrees of freedom can be isolated. All three methods use constrained optimization to rapidly find the TS without an initial Hessian evaluation. The algorithms highlight how efficiently the TS can be located on a reduced surface, where the rest of the degrees of freedom are minimized. The first method uses a nonpositive definite quasi-Newton update for the reduced degrees of freedom. The second uses Shepard interpolation to fit the Hessian and starts from a set of points that bound the TS. The third directly uses a finite difference scheme to calculate the reduced degrees of freedom of the Hessian of the entire system, and searches for the TS on the full potential energy surface. All three methods are tested on an epoxide hydrolase cluster, and the ring formations of cyclohexane and cyclobutenone. The results indicate that all the methods are able to converge quite rapidly to the correct TS, but that the finite difference approach is the most efficient.

Methods for finding transition states on reduced potential energy surfaces.

PubMed

Burger, Steven K; Ayers, Paul W

2010-06-21

Three new algorithms are presented for determining transition state (TS) structures on the reduced potential energy surface, that is, for problems in which a few important degrees of freedom can be isolated. All three methods use constrained optimization to rapidly find the TS without an initial Hessian evaluation. The algorithms highlight how efficiently the TS can be located on a reduced surface, where the rest of the degrees of freedom are minimized. The first method uses a nonpositive definite quasi-Newton update for the reduced degrees of freedom. The second uses Shepard interpolation to fit the Hessian and starts from a set of points that bound the TS. The third directly uses a finite difference scheme to calculate the reduced degrees of freedom of the Hessian of the entire system, and searches for the TS on the full potential energy surface. All three methods are tested on an epoxide hydrolase cluster, and the ring formations of cyclohexane and cyclobutenone. The results indicate that all the methods are able to converge quite rapidly to the correct TS, but that the finite difference approach is the most efficient.

Outage Probability Minimization for Energy Harvesting Cognitive Radio Sensor Networks

PubMed Central

Zhang, Fan; Jing, Tao; Huo, Yan; Jiang, Kaiwei

2017-01-01

The incorporation of cognitive radio (CR) capability in wireless sensor networks yields a promising network paradigm known as CR sensor networks (CRSNs), which is able to provide spectrum efficient data communication. However, due to the high energy consumption results from spectrum sensing, as well as subsequent data transmission, the energy supply for the conventional sensor nodes powered by batteries is regarded as a severe bottleneck for sustainable operation. The energy harvesting technique, which gathers energy from the ambient environment, is regarded as a promising solution to perpetually power-up energy-limited devices with a continual source of energy. Therefore, applying the energy harvesting (EH) technique in CRSNs is able to facilitate the self-sustainability of the energy-limited sensors. The primary concern of this study is to design sensing-transmission policies to minimize the long-term outage probability of EH-powered CR sensor nodes. We formulate this problem as an infinite-horizon discounted Markov decision process and propose an ϵ-optimal sensing-transmission (ST) policy through using the value iteration algorithm. ϵ is the error bound between the ST policy and the optimal policy, which can be pre-defined according to the actual need. Moreover, for a special case that the signal-to-noise (SNR) power ratio is sufficiently high, we present an efficient transmission (ET) policy and prove that the ET policy achieves the same performance with the ST policy. Finally, extensive simulations are conducted to evaluate the performance of the proposed policies and the impaction of various network parameters. PMID:28125023

Outage Probability Minimization for Energy Harvesting Cognitive Radio Sensor Networks.

PubMed

Zhang, Fan; Jing, Tao; Huo, Yan; Jiang, Kaiwei

2017-01-24

The incorporation of cognitive radio (CR) capability in wireless sensor networks yields a promising network paradigm known as CR sensor networks (CRSNs), which is able to provide spectrum efficient data communication. However, due to the high energy consumption results from spectrum sensing, as well as subsequent data transmission, the energy supply for the conventional sensor nodes powered by batteries is regarded as a severe bottleneck for sustainable operation. The energy harvesting technique, which gathers energy from the ambient environment, is regarded as a promising solution to perpetually power-up energy-limited devices with a continual source of energy. Therefore, applying the energy harvesting (EH) technique in CRSNs is able to facilitate the self-sustainability of the energy-limited sensors. The primary concern of this study is to design sensing-transmission policies to minimize the long-term outage probability of EH-powered CR sensor nodes. We formulate this problem as an infinite-horizon discounted Markov decision process and propose an ϵ -optimal sensing-transmission (ST) policy through using the value iteration algorithm. ϵ is the error bound between the ST policy and the optimal policy, which can be pre-defined according to the actual need. Moreover, for a special case that the signal-to-noise (SNR) power ratio is sufficiently high, we present an efficient transmission (ET) policy and prove that the ET policy achieves the same performance with the ST policy. Finally, extensive simulations are conducted to evaluate the performance of the proposed policies and the impaction of various network parameters.

Potential Coastal Pumped Hydroelectric Energy Storage Locations Identified using GIS-based Topographic Analysis

NASA Astrophysics Data System (ADS)

Parsons, R.; Barnhart, C. J.; Benson, S. M.

2013-12-01

Large-scale electrical energy storage could accommodate variable, weather dependent energy resources such as wind and solar. Pumped hydroelectric energy storage (PHS) and compressed energy storage area (CAES) have life cycle energy and financial costs that are an order of magnitude lower than conventional electrochemical storage technologies. However PHS and CAES storage technologies require specific geologic conditions. Conventional PHS requires an upper and lower reservoir separated by at least 100 m of head, but no more than 10 km in horizontal distance. Conventional PHS also impacts fresh water supplies, riparian ecosystems, and hydrologic environments. A PHS facility that uses the ocean as the lower reservoir benefits from a smaller footprint, minimal freshwater impact, and the potential to be located near off shore wind resources and population centers. Although technologically nascent, today one coastal PHS facility exists. The storage potential for coastal PHS is unknown. Can coastal PHS play a significant role in augmenting future power grids with a high faction of renewable energy supply? In this study we employ GIS-based topographic analysis to quantify the coastal PHS potential of several geographic locations, including California, Chile and Peru. We developed automated techniques that seek local topographic minima in 90 m spatial resolution shuttle radar topography mission (SRTM) digital elevation models (DEM) that satisfy the following criteria conducive to PHS: within 10 km from the sea; minimum elevation 150 m; maximum elevation 1000 m. Preliminary results suggest the global potential for coastal PHS could be very significant. For example, in northern Chile we have identified over 60 locations that satisfy the above criteria. Two of these locations could store over 10 million cubic meters of water or several GWh of energy. We plan to report a global database of candidate coastal PHS locations and to estimate their energy storage capacity.

DeePMD-kit: A deep learning package for many-body potential energy representation and molecular dynamics

NASA Astrophysics Data System (ADS)

Wang, Han; Zhang, Linfeng; Han, Jiequn; E, Weinan

2018-07-01

Recent developments in many-body potential energy representation via deep learning have brought new hopes to addressing the accuracy-versus-efficiency dilemma in molecular simulations. Here we describe DeePMD-kit, a package written in Python/C++ that has been designed to minimize the effort required to build deep learning based representation of potential energy and force field and to perform molecular dynamics. Potential applications of DeePMD-kit span from finite molecules to extended systems and from metallic systems to chemically bonded systems. DeePMD-kit is interfaced with TensorFlow, one of the most popular deep learning frameworks, making the training process highly automatic and efficient. On the other end, DeePMD-kit is interfaced with high-performance classical molecular dynamics and quantum (path-integral) molecular dynamics packages, i.e., LAMMPS and the i-PI, respectively. Thus, upon training, the potential energy and force field models can be used to perform efficient molecular simulations for different purposes. As an example of the many potential applications of the package, we use DeePMD-kit to learn the interatomic potential energy and forces of a water model using data obtained from density functional theory. We demonstrate that the resulted molecular dynamics model reproduces accurately the structural information contained in the original model.

Power allocation strategies to minimize energy consumption in wireless body area networks.

PubMed

Kailas, Aravind

2011-01-01

The wide scale deployment of wireless body area networks (WBANs) hinges on designing energy efficient communication protocols to support the reliable communication as well as to prolong the network lifetime. Cooperative communications, a relatively new idea in wireless communications, offers the benefits of multi-antenna systems, thereby improving the link reliability and boosting energy efficiency. In this short paper, the advantages of resorting to cooperative communications for WBANs in terms of minimized energy consumption are investigated. Adopting an energy model that encompasses energy consumptions in the transmitter and receiver circuits, and transmitting energy per bit, it is seen that cooperative transmission can improve energy efficiency of the wireless network. In particular, the problem of optimal power allocation is studied with the constraint of targeted outage probability. Two strategies of power allocation are considered: power allocation with and without posture state information. Using analysis and simulation-based results, two key points are demonstrated: (i) allocating power to the on-body sensors making use of the posture information can reduce the total energy consumption of the WBAN; and (ii) when the channel condition is good, it is better to recruit less relays for cooperation to enhance energy efficiency.

The Energy-Water Nexus: potential groundwater-quality degradation associated with production of shale gas

USGS Publications Warehouse

Kharaka, Yousif K.; Thordsen, James J.; Conaway, Christopher H.; Thomas, Randal B.

2013-01-01

Oil and natural gas have been the main sources of primary energy in the USA, providing 63% of the total energy consumption in 2011. Petroleum production, drilling operations, and improperly sealed abandoned wells have caused significant local groundwater contamination in many states, including at the USGS OSPER sites in Oklahoma. The potential for groundwater contamination is higher when producing natural gas and oil from unconventional sources of energy, including shale and tight sandstones. These reservoirs require horizontally-completed wells and massive hydraulic fracturing that injects large volumes (up to 50,000 m3/well) of high-pressured water with added proppant, and toxic organic and inorganic chemicals. Recent results show that flow back and produced waters from Haynesville (Texas) and Marcellus (Pennsylvania) Shale have high salinities (≥200,000 mg/L TDS) and high NORMs (up to 10,000 picocuries/L) concentrations. A major research effort is needed worldwide to minimize all potential environmental impacts, especially groundwater contamination and induced seismicity, when producing these extremely important new sources of energy.

Shifts in wind energy potential following land-use driven vegetation dynamics in complex terrain.

PubMed

Fang, Jiannong; Peringer, Alexander; Stupariu, Mihai-Sorin; Pǎtru-Stupariu, Ileana; Buttler, Alexandre; Golay, Francois; Porté-Agel, Fernando

2018-10-15

Many mountainous regions with high wind energy potential are characterized by multi-scale variabilities of vegetation in both spatial and time dimensions, which strongly affect the spatial distribution of wind resource and its time evolution. To this end, we developed a coupled interdisciplinary modeling framework capable of assessing the shifts in wind energy potential following land-use driven vegetation dynamics in complex mountain terrain. It was applied to a case study area in the Romanian Carpathians. The results show that the overall shifts in wind energy potential following the changes of vegetation pattern due to different land-use policies can be dramatic. This suggests that the planning of wind energy project should be integrated with the land-use planning at a specific site to ensure that the expected energy production of the planned wind farm can be reached over its entire lifetime. Moreover, the changes in the spatial distribution of wind and turbulence under different scenarios of land-use are complex, and they must be taken into account in the micro-siting of wind turbines to maximize wind energy production and minimize fatigue loads (and associated maintenance costs). The proposed new modeling framework offers, for the first time, a powerful tool for assessing long-term variability in local wind energy potential that emerges from land-use change driven vegetation dynamics over complex terrain. Following a previously unexplored pathway of cause-effect relationships, it demonstrates a new linkage of agro- and forest policies in landscape development with an ultimate trade-off between renewable energy production and biodiversity targets. Moreover, it can be extended to study the potential effects of micro-climatic changes associated with wind farms on vegetation development (growth and patterning), which could in turn have a long-term feedback effect on wind resource distribution in mountainous regions. Copyright © 2018 Elsevier B.V. All rights

Dynamic Electron Correlation Effects on the Ground State Potential Energy Surface of a Retinal Chromophore Model.

PubMed

Gozem, Samer; Huntress, Mark; Schapiro, Igor; Lindh, Roland; Granovsky, Alexander A; Angeli, Celestino; Olivucci, Massimo

2012-11-13

The ground state potential energy surface of the retinal chromophore of visual pigments (e.g., bovine rhodopsin) features a low-lying conical intersection surrounded by regions with variable charge-transfer and diradical electronic structures. This implies that dynamic electron correlation may have a large effect on the shape of the force fields driving its reactivity. To investigate this effect, we focus on mapping the potential energy for three paths located along the ground state CASSCF potential energy surface of the penta-2,4-dieniminium cation taken as a minimal model of the retinal chromophore. The first path spans the bond length alternation coordinate and intercepts a conical intersection point. The other two are minimum energy paths along two distinct but kinetically competitive thermal isomerization coordinates. We show that the effect of introducing the missing dynamic electron correlation variationally (with MRCISD) and perturbatively (with the CASPT2, NEVPT2, and XMCQDPT2 methods) leads, invariably, to a stabilization of the regions with charge transfer character and to a significant reshaping of the reference CASSCF potential energy surface and suggesting a change in the dominating isomerization mechanism. The possible impact of such a correction on the photoisomerization of the retinal chromophore is discussed.

Minimizing center of mass vertical movement increases metabolic cost in walking.

PubMed

Ortega, Justus D; Farley, Claire T

2005-12-01

A human walker vaults up and over each stance limb like an inverted pendulum. This similarity suggests that the vertical motion of a walker's center of mass reduces metabolic cost by providing a mechanism for pendulum-like mechanical energy exchange. Alternatively, some researchers have hypothesized that minimizing vertical movements of the center of mass during walking minimizes the metabolic cost, and this view remains prevalent in clinical gait analysis. We examined the relationship between vertical movement and metabolic cost by having human subjects walk normally and with minimal center of mass vertical movement ("flat-trajectory walking"). In flat-trajectory walking, subjects reduced center of mass vertical displacement by an average of 69% (P = 0.0001) but consumed approximately twice as much metabolic energy over a range of speeds (0.7-1.8 m/s) (P = 0.0001). In flat-trajectory walking, passive pendulum-like mechanical energy exchange provided only a small portion of the energy required to accelerate the center of mass because gravitational potential energy fluctuated minimally. Thus, despite the smaller vertical movements in flat-trajectory walking, the net external mechanical work needed to move the center of mass was similar in both types of walking (P = 0.73). Subjects walked with more flexed stance limbs in flat-trajectory walking (P < 0.001), and the resultant increase in stance limb force generation likely helped cause the doubling in metabolic cost compared with normal walking. Regardless of the cause, these findings clearly demonstrate that human walkers consume substantially more metabolic energy when they minimize vertical motion.

Energy minimization of mobile video devices with a hardware H.264/AVC encoder based on energy-rate-distortion optimization

NASA Astrophysics Data System (ADS)

Kang, Donghun; Lee, Jungeon; Jung, Jongpil; Lee, Chul-Hee; Kyung, Chong-Min

2014-09-01

In mobile video systems powered by battery, reducing the encoder's compression energy consumption is critical to prolong its lifetime. Previous Energy-rate-distortion (E-R-D) optimization methods based on a software codec is not suitable for practical mobile camera systems because the energy consumption is too large and encoding rate is too low. In this paper, we propose an E-R-D model for the hardware codec based on the gate-level simulation framework to measure the switching activity and the energy consumption. From the proposed E-R-D model, an energy minimizing algorithm for mobile video camera sensor have been developed with the GOP (Group of Pictures) size and QP(Quantization Parameter) as run-time control variables. Our experimental results show that the proposed algorithm provides up to 31.76% of energy consumption saving while satisfying the rate and distortion constraints.

Minimizing the injury potential of deploying airbag interactions with car occupants.

PubMed

Mertz, Harold J; Prasad, Priya; Dalmotas, Dainius

2013-11-01

Minimizing the injury potential of the interactions between deploying airbags and car occupants is the major issue with the design of airbag systems. This concern was identified in 1964 by Carl Clark when he presented the results of human volunteer and dummy testing of the "Airstop" system that was being developed for aircraft. The following is a chronological summary of the actions taken by the car manufacturers, airbag suppliers, SAE and ISO task groups, research institutes and universities, and consumer and government groups to address this issue.

Evaluation of the carotid artery stenosis based on minimization of mechanical energy loss of the blood flow.

PubMed

Sia, Sheau Fung; Zhao, Xihai; Li, Rui; Zhang, Yu; Chong, Winston; He, Le; Chen, Yu

2016-11-01

Internal carotid artery stenosis requires an accurate risk assessment for the prevention of stroke. Although the internal carotid artery area stenosis ratio at the common carotid artery bifurcation can be used as one of the diagnostic methods of internal carotid artery stenosis, the accuracy of results would still depend on the measurement techniques. The purpose of this study is to propose a novel method to estimate the effect of internal carotid artery stenosis on the blood flow based on the concept of minimization of energy loss. Eight internal carotid arteries from different medical centers were diagnosed as stenosed internal carotid arteries, as plaques were found at different locations on the vessel. A computational fluid dynamics solver was developed based on an open-source code (OpenFOAM) to test the flow ratio and energy loss of those stenosed internal carotid arteries. For comparison, a healthy internal carotid artery and an idealized internal carotid artery model have also been tested and compared with stenosed internal carotid artery in terms of flow ratio and energy loss. We found that at a given common carotid artery bifurcation, there must be a certain flow distribution in the internal carotid artery and external carotid artery, for which the total energy loss at the bifurcation is at a minimum; for a given common carotid artery flow rate, an irregular shaped plaque at the bifurcation constantly resulted in a large value of minimization of energy loss. Thus, minimization of energy loss can be used as an indicator for the estimation of internal carotid artery stenosis.

Cosmological dynamics with non-minimally coupled scalar field and a constant potential function

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

Hrycyna, Orest; Szydłowski, Marek, E-mail: orest.hrycyna@ncbj.gov.pl, E-mail: marek.szydlowski@uj.edu.pl

2015-11-01

Dynamical systems methods are used to investigate global behaviour of the spatially flat Friedmann-Robertson-Walker cosmological model in gravitational theory with a non-minimally coupled scalar field and a constant potential function. We show that the system can be reduced to an autonomous three-dimensional dynamical system and additionally is equipped with an invariant manifold corresponding to an accelerated expansion of the universe. Using this invariant manifold we find an exact solution of the reduced dynamics. We investigate all solutions for all admissible initial conditions using theory of dynamical systems to obtain a classification of all evolutional paths. The right-hand sides of themore » dynamical system depend crucially on the value of the non-minimal coupling constant therefore we study bifurcation values of this parameter under which the structure of the phase space changes qualitatively. We found a special bifurcation value of the non-minimal coupling constant which is distinguished by dynamics of the model and may suggest some additional symmetry in matter sector of the theory.« less

Energy-efficient approach to minimizing the energy consumption in an extended job-shop scheduling problem

NASA Astrophysics Data System (ADS)

Tang, Dunbing; Dai, Min

2015-09-01

The traditional production planning and scheduling problems consider performance indicators like time, cost and quality as optimization objectives in manufacturing processes. However, environmentally-friendly factors like energy consumption of production have not been completely taken into consideration. Against this background, this paper addresses an approach to modify a given schedule generated by a production planning and scheduling system in a job shop floor, where machine tools can work at different cutting speeds. It can adjust the cutting speeds of the operations while keeping the original assignment and processing sequence of operations of each job fixed in order to obtain energy savings. First, the proposed approach, based on a mixed integer programming mathematical model, changes the total idle time of the given schedule to minimize energy consumption in the job shop floor while accepting the optimal solution of the scheduling objective, makespan. Then, a genetic-simulated annealing algorithm is used to explore the optimal solution due to the fact that the problem is strongly NP-hard. Finally, the effectiveness of the approach is performed smalland large-size instances, respectively. The experimental results show that the approach can save 5%-10% of the average energy consumption while accepting the optimal solution of the makespan in small-size instances. In addition, the average maximum energy saving ratio can reach to 13%. And it can save approximately 1%-4% of the average energy consumption and approximately 2.4% of the average maximum energy while accepting the near-optimal solution of the makespan in large-size instances. The proposed research provides an interesting point to explore an energy-aware schedule optimization for a traditional production planning and scheduling problem.

FPGA design for constrained energy minimization

NASA Astrophysics Data System (ADS)

Wang, Jianwei; Chang, Chein-I.; Cao, Mang

2004-02-01

The Constrained Energy Minimization (CEM) has been widely used for hyperspectral detection and classification. The feasibility of implementing the CEM as a real-time processing algorithm in systolic arrays has been also demonstrated. The main challenge of realizing the CEM in hardware architecture in the computation of the inverse of the data correlation matrix performed in the CEM, which requires a complete set of data samples. In order to cope with this problem, the data correlation matrix must be calculated in a causal manner which only needs data samples up to the sample at the time it is processed. This paper presents a Field Programmable Gate Arrays (FPGA) design of such a causal CEM. The main feature of the proposed FPGA design is to use the Coordinate Rotation DIgital Computer (CORDIC) algorithm that can convert a Givens rotation of a vector to a set of shift-add operations. As a result, the CORDIC algorithm can be easily implemented in hardware architecture, therefore in FPGA. Since the computation of the inverse of the data correlction involves a series of Givens rotations, the utility of the CORDIC algorithm allows the causal CEM to perform real-time processing in FPGA. In this paper, an FPGA implementation of the causal CEM will be studied and its detailed architecture will be also described.

Progress in calculating the potential energy surface of H3+.

PubMed

Adamowicz, Ludwik; Pavanello, Michele

2012-11-13

The most accurate electronic structure calculations are performed using wave function expansions in terms of basis functions explicitly dependent on the inter-electron distances. In our recent work, we use such basis functions to calculate a highly accurate potential energy surface (PES) for the H(3)(+) ion. The functions are explicitly correlated Gaussians, which include inter-electron distances in the exponent. Key to obtaining the high accuracy in the calculations has been the use of the analytical energy gradient determined with respect to the Gaussian exponential parameters in the minimization of the Rayleigh-Ritz variational energy functional. The effective elimination of linear dependences between the basis functions and the automatic adjustment of the positions of the Gaussian centres to the changing molecular geometry of the system are the keys to the success of the computational procedure. After adiabatic and relativistic corrections are added to the PES and with an effective accounting of the non-adiabatic effects in the calculation of the rotational/vibrational states, the experimental H(3)(+) rovibrational spectrum is reproduced at the 0.1 cm(-1) accuracy level up to 16,600 cm(-1) above the ground state.

Direct Density Functional Energy Minimization using an Tetrahedral Finite Element Grid

NASA Astrophysics Data System (ADS)

Vaught, A.; Schmidt, K. E.; Chizmeshya, A. V. G.

1998-03-01

We describe an O(N) (N proportional to volume) technique for solving electronic structure problems using the finite element method (FEM). A real--space tetrahedral grid is used as a basis to represent the electronic density, of a free or periodic system and Poisson's equation is solved as a boundary value problem. Nuclear cusps are treated using a local grid consisting of radial elements. These features facilitate the implementation of complicated energy functionals and permit a direct (constrained) energy minimization with respect to the density. We demonstrate the usefulness of the scheme by calculating the binding trends and polarizabilities of a number of atoms and molecules using a number of recently proposed non--local, orbital--free kinetic energy functionals^1,2. Scaling behavior, computational efficiency and the generalization to band--structure will also be discussed. indent 0 pt øbeylines øbeyspaces skip 0 pt ^1 P. Garcia-Gonzalez, J.E. Alvarellos and E. Chacon, Phys. Rev. B 54, 1897 (1996). ^2 A. J. Thakkar, Phys.Rev.B 46, 6920 (1992).

Solar Energy Development and Aquatic Ecosystems in the Southwestern United States: Potential Impacts, Mitigation, and Research Needs

NASA Astrophysics Data System (ADS)

Grippo, Mark; Hayse, John W.; O'Connor, Ben L.

2015-01-01

The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found to attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface-groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems.

Solar energy development and aquatic ecosystems in the southwestern United States: potential impacts, mitigation, and research needs.

PubMed

Grippo, Mark; Hayse, John W; O'Connor, Ben L

2015-01-01

The cumulative impacts of utility-scale solar energy facilities on aquatic ecosystems in the Southwestern United States are of concern, considering the many existing regional anthropogenic stressors. We review the potential impacts of solar energy development on aquatic habitat and biota. The greatest potential for impacts is related to the loss, fragmentation, or prolonged drying of ephemeral water bodies and drainage networks resulting from the loss of desert washes within the construction footprint of the facility. Groundwater-dependent aquatic habitat may also be affected by operational groundwater withdrawal in the case of water-intensive solar technologies. Solar panels have also been found to attract aquatic insects and waterbirds, potentially resulting in mortality. Avoiding construction activity near perennial and intermittent surface waters is the primary means of reducing impacts on aquatic habitats, followed by measures to minimize erosion, sedimentation, and contaminant inputs into waterways. Currently, significant data gaps make solar facility impact assessment and mitigation more difficult. Examples include the need for more regional and site-specific studies of surface-groundwater connectivity, more detailed maps of regional stream networks and riparian vegetation corridors, as well as surveys of the aquatic communities inhabiting ephemeral streams. In addition, because they often lack regulatory protection, there is also a need to develop valuation criteria for ephemeral waters based on their ecological and hydrologic function within the landscape. By addressing these research needs, we can achieve the goal of greater reliance on solar energy, while at the same time minimizing impacts on desert ecosystems.

Energy spread minimization in a cascaded laser wakefield accelerator via velocity bunching

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

Zhang, Zhijun; Li, Wentao; Wang, Wentao

2016-05-15

We propose a scheme to minimize the energy spread of an electron beam (e-beam) in a cascaded laser wakefield accelerator to the one-thousandth-level by inserting a stage to compress its longitudinal spatial distribution. In this scheme, three-segment plasma stages are designed for electron injection, e-beam length compression, and e-beam acceleration, respectively. The trapped e-beam in the injection stage is transferred to the zero-phase region at the center of one wakefield period in the compression stage where the length of the e-beam can be greatly shortened owing to the velocity bunching. After being seeded into the third stage for acceleration, themore » e-beam can be accelerated to a much higher energy before its energy chirp is compensated owing to the shortened e-beam length. A one-dimensional theory and two-dimensional particle-in-cell simulations have demonstrated this scheme and an e-beam with 0.2% rms energy spread and low transverse emittance could be generated without loss of charge.« less

Dark energy, non-minimal couplings and the origin of cosmic magnetic fields

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

Jiménez, Jose Beltrán; Maroto, Antonio L., E-mail: jobeltra@fis.ucm.es, E-mail: maroto@fis.ucm.es

2010-12-01

In this work we consider the most general electromagnetic theory in curved space-time leading to linear second order differential equations, including non-minimal couplings to the space-time curvature. We assume the presence of a temporal electromagnetic background whose energy density plays the role of dark energy, as has been recently suggested. Imposing the consistency of the theory in the weak-field limit, we show that it reduces to standard electromagnetism in the presence of an effective electromagnetic current which is generated by the momentum density of the matter/energy distribution, even for neutral sources. This implies that in the presence of dark energy,more » the motion of large-scale structures generates magnetic fields. Estimates of the present amplitude of the generated seed fields for typical spiral galaxies could reach 10{sup −9} G without any amplification. In the case of compact rotating objects, the theory predicts their magnetic moments to be related to their angular momenta in the way suggested by the so called Schuster-Blackett conjecture.« less

FAST TRACK COMMUNICATION: Freezing and extreme-value statistics in a random energy model with logarithmically correlated potential

NASA Astrophysics Data System (ADS)

Fyodorov, Yan V.; Bouchaud, Jean-Philippe

2008-09-01

We investigate some implications of the freezing scenario proposed by Carpentier and Le Doussal (CLD) for a random energy model (REM) with logarithmically correlated random potential. We introduce a particular (circular) variant of the model, and show that the integer moments of the partition function in the high-temperature phase are given by the well-known Dyson Coulomb gas integrals. The CLD freezing scenario allows one to use those moments for extracting the distribution of the free energy in both high- and low-temperature phases. In particular, it yields the full distribution of the minimal value in the potential sequence. This provides an explicit new class of extreme-value statistics for strongly correlated variables, manifestly different from the standard Gumbel class.

Radial Symmetry of p-Harmonic Minimizers

NASA Astrophysics Data System (ADS)

Koski, Aleksis; Onninen, Jani

2018-03-01

"It is still not known if the radial cavitating minimizers obtained by uc(Ball) (Philos Trans R Soc Lond A 306:557-611, 1982) (and subsequently by many others) are global minimizers of any physically reasonable nonlinearly elastic energy". This quotation is from uc(Sivaloganathan) and uc(Spector) (Ann Inst Henri Poincaré Anal Non Linéaire 25(1):201-213, 2008) and seems to be still accurate. The model case of the p-harmonic energy is considered here. We prove that the planar radial minimizers are indeed the global minimizers provided we prescribe the admissible deformations on the boundary. In the traction free setting, however, even the identity map need not be a global minimizer.

Mesohysteresis model for ferromagnetic materials by minimization of the micromagnetic free energy

NASA Astrophysics Data System (ADS)

van den Berg, A.; Dupré, L.; Van de Wiele, B.; Crevecoeur, G.

2009-04-01

To study the connection between macroscopic hysteretic behavior and the microstructural properties, this paper presents and validates a new material dependent three-dimensional mesoscopic magnetic hysteresis model. In the presented mesoscopic description, the different micromagnetic energy terms are reformulated on the space scale of the magnetic domains. The sample is discretized in cubic cells, each with a local stress state, local bcc crystallographic axes, etc. The magnetization is assumed to align with one of the three crystallographic axes, in positive or negative sense, defining six volume fractions within each cell. The micromagnetic Gibbs free energy is described in terms of these volume fractions. Hysteresis loops are computed by minimizing the mesoscopic Gibbs free energy using a modified gradient search for a sequence of external applied fields. To validate the mesohysteresis model, we studied the magnetic memory properties. Numerical experiments reveal that (1) minor hysteresis loops are indeed closed and (2) the closed minor loops are erased from the memory.

An integrated assessment of the potential of agricultural and forestry residues for energy production in China

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

Gao, Ji; Zhang, Aiping; Lam, Shu Kee

Biomass has been widely recognized as an important energy source with high potential to reduce greenhouse gas emissions while minimizing environmental pollution. In this study, we employ the Global Change Assessment Model to estimate the potential of agricultural and forestry residue biomass for energy production in China. Potential availability of residue biomass as an energy source was analyzed for the 21st century under different climate policy scenarios. Currently, the amount of total annual residue biomass, averaged over 2003-2007, is around 15519PJ in China, consisting of 10818PJ from agriculture residues (70%) and 4701PJ forestry residues (30%). We estimate that 12693PJ ofmore » the total biomass is available for energy production, with 66% derived from agricultural residue and 34% from forestry residue. Most of the available residue is from south central China (3347PJ), east China (2862PJ) and south-west China (2229PJ), which combined exceeds 66% of the total national biomass. Under the reference scenario without carbon tax, the potential availability of residue biomass for energy production is projected to be 3380PJ by 2050 and 4108PJ by 2095, respectively. When carbon tax is imposed, biomass availability increases substantially. For the CCS 450ppm scenario, availability of biomass increases to 9002PJ (2050) and 11524PJ (2095), respectively. For the 450ppm scenario without CCS, 9183 (2050) and 11150PJ (2095) residue biomass, respectively, is projected to be available. Moreover, the implementation of CCS will have a little impact on the supply of residue biomass after 2035. Our results suggest that residue biomass has the potential to be an important component in China's sustainable energy production portfolio. As a low carbon emission energy source, climate change policies that involve carbon tariff and CCS technology promote the use of residue biomass for energy production in a low carbon-constrained world.« less

Assessment of the potential of halophytes as energy crops for the electric utility industry. Final report

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

Goodin, J.R.

1984-09-01

This technical report assesses and estimates the potential of selected halophytes as future renewable energy resources, especially by US electric utilities, and familiarizes nonspecialists with research and development problems that must be resolved before these energy sources can become dependable supplies of energy. A literature search related to both indigenous and exotic species of halophytes has been done and appropriate terrestrial species have been selected. Selection criteria include: total biomass potential, genetic constraints, establishment and cultivation requirements, regions of suitability, secondary credits, and a number of other factors. Based on these selection criteria, for the arid western states with highmore » levels of salinity in water and/or soils, there is little potential for energy feedstocks derived from grasses and herbaceous forbs. Likewise, coastal marshes, estuaries, and mangrove swamps, although excellent biomass producers, are too limited by region and have too many ecological and environmental problems for consideration. The deep-rooted, perennial woody shrubs indigenous to many saline regions of the west provide the best potential. The number of species in this group is limited, and Atriplex canescens, Sarcobatus vermiculatus, and Chrysothamnus nauseosus are the three species with the greatest biological potential. These shrubs would receive minimal energy inputs in cultivation, would not compete with agricultural land, and would restore productivity to severely disturbed sites. One might logically expect to achieve biomass feedstock yields of three to five tons/acre/yr on a long-term sustainable basis. The possibility also exists that exotic species might be introduced. 67 references, 1 figure, 5 tables.« less

Energy performance and savings potentials with skylights

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

Arasteh, D.; Johnson, R.; Selkowitz, S.

1984-12-01

This study systematically explores the energy effects of skylight systems in a prototypical office building module and examines the savings from daylighting. For specific climates, roof/skylight characteristics are identified that minimize total energy or peak electrical demand. Simplified techniques for energy performance calculation are also presented based on a multiple regression analysis of our data base so that one may easily evaluate daylighting's effects on total and component energy loads and electrical peaks. This provides additional insights into the influence of skylight parameters on energy consumption and electrical peaks. We use the DOE-2.1B energy analysis program with newly incorporated daylightingmore » algorithms to determine hourly, monthly, and annual impacts of daylighting strategies on electrical lighting consumption, cooling, heating, fan power, peak electrical demands, and total energy use. A data base of more than 2000 parametric simulations for 14 US climates has been generated. Parameters varied include skylight-to-roof ratio, shading coefficient, visible transmittance, skylight well light loss, electric lighting power density, roof heat transfer coefficient, and electric lighting control type. 14 references, 13 figures, 4 tables.« less

Optimizing rice yields while minimizing yield-scaled global warming potential.

PubMed

Pittelkow, Cameron M; Adviento-Borbe, Maria A; van Kessel, Chris; Hill, James E; Linquist, Bruce A

2014-05-01

To meet growing global food demand with limited land and reduced environmental impact, agricultural greenhouse gas (GHG) emissions are increasingly evaluated with respect to crop productivity, i.e., on a yield-scaled as opposed to area basis. Here, we compiled available field data on CH4 and N2 O emissions from rice production systems to test the hypothesis that in response to fertilizer nitrogen (N) addition, yield-scaled global warming potential (GWP) will be minimized at N rates that maximize yields. Within each study, yield N surplus was calculated to estimate deficit or excess N application rates with respect to the optimal N rate (defined as the N rate at which maximum yield was achieved). Relationships between yield N surplus and GHG emissions were assessed using linear and nonlinear mixed-effects models. Results indicate that yields increased in response to increasing N surplus when moving from deficit to optimal N rates. At N rates contributing to a yield N surplus, N2 O and yield-scaled N2 O emissions increased exponentially. In contrast, CH4 emissions were not impacted by N inputs. Accordingly, yield-scaled CH4 emissions decreased with N addition. Overall, yield-scaled GWP was minimized at optimal N rates, decreasing by 21% compared to treatments without N addition. These results are unique compared to aerobic cropping systems in which N2 O emissions are the primary contributor to GWP, meaning yield-scaled GWP may not necessarily decrease for aerobic crops when yields are optimized by N fertilizer addition. Balancing gains in agricultural productivity with climate change concerns, this work supports the concept that high rice yields can be achieved with minimal yield-scaled GWP through optimal N application rates. Moreover, additional improvements in N use efficiency may further reduce yield-scaled GWP, thereby strengthening the economic and environmental sustainability of rice systems. © 2013 John Wiley & Sons Ltd.

Potential Advantages of Reusing Potentially Contaminated Land for Renewable Energy Fact Sheet

EPA Pesticide Factsheets

EPA promotes the reuse of potentially contaminated lands and landfills for renewable energy. This strategy creates new markets for potentially contaminated lands, while providing a sustainable land development strategy for renewable energy.

Investigating energy-saving potentials in the cloud.

PubMed

Lee, Da-Sheng

2014-02-20

Collecting webpage messages can serve as a sensor for investigating the energy-saving potential of buildings. Focusing on stores, a cloud sensor system is developed to collect data and determine their energy-saving potential. The owner of a store under investigation must register online, report the store address, area, and the customer ID number on the electric meter. The cloud sensor system automatically surveys the energy usage records by connecting to the power company website and calculating the energy use index (EUI) of the store. Other data includes the chain store check, company capital, location price, and the influence of weather conditions on the store; even the exposure frequency of store under investigation may impact the energy usage collected online. After collecting data from numerous stores, a multi-dimensional data array is constructed to determine energy-saving potential by identifying stores with similarity conditions. Similarity conditions refer to analyzed results that indicate that two stores have similar capital, business scale, weather conditions, and exposure frequency on web. Calculating the EUI difference or pure technical efficiency of stores, the energy-saving potential is determined. In this study, a real case study is performed. An 8-dimensional (8D) data array is constructed by surveying web data related to 67 stores. Then, this study investigated the savings potential of the 33 stores, using a site visit, and employed the cloud sensor system to determine the saving potential. The case study results show good agreement between the data obtained by the site visit and the cloud investigation, with errors within 4.17%. Among 33 the samples, eight stores have low saving potentials of less than 5%. The developed sensor on the cloud successfully identifies them as having low saving potential and avoids wasting money on the site visit.

Investigating Energy-Saving Potentials in the Cloud

PubMed Central

Lee, Da-Sheng

2014-01-01

Collecting webpage messages can serve as a sensor for investigating the energy-saving potential of buildings. Focusing on stores, a cloud sensor system is developed to collect data and determine their energy-saving potential. The owner of a store under investigation must register online, report the store address, area, and the customer ID number on the electric meter. The cloud sensor system automatically surveys the energy usage records by connecting to the power company website and calculating the energy use index (EUI) of the store. Other data includes the chain store check, company capital, location price, and the influence of weather conditions on the store; even the exposure frequency of store under investigation may impact the energy usage collected online. After collecting data from numerous stores, a multi-dimensional data array is constructed to determine energy-saving potential by identifying stores with similarity conditions. Similarity conditions refer to analyzed results that indicate that two stores have similar capital, business scale, weather conditions, and exposure frequency on web. Calculating the EUI difference or pure technical efficiency of stores, the energy-saving potential is determined. In this study, a real case study is performed. An 8-dimensional (8D) data array is constructed by surveying web data related to 67 stores. Then, this study investigated the savings potential of the 33 stores, using a site visit, and employed the cloud sensor system to determine the saving potential. The case study results show good agreement between the data obtained by the site visit and the cloud investigation, with errors within 4.17%. Among 33 the samples, eight stores have low saving potentials of less than 5%. The developed sensor on the cloud successfully identifies them as having low saving potential and avoids wasting money on the site visit. PMID:24561405

Wave Energy Potential in the Latvian EEZ

NASA Astrophysics Data System (ADS)

Beriņš, J.; Beriņš, J.; Kalnačs, J.; Kalnačs, A.

2016-06-01

The present article deals with one of the alternative forms of energy - sea wave energy potential in the Latvian Exclusice Economic Zone (EEZ). Results have been achieved using a new method - VEVPP. Calculations have been performed using the data on wave parameters over the past five years (2010-2014). We have also considered wave energy potential in the Gulf of Riga. The conclusions have been drawn on the recommended methodology for the sea wave potential and power calculations for wave-power plant pre-design stage.

Isometric immersions, energy minimization and self-similar buckling in non-Euclidean elastic sheets

NASA Astrophysics Data System (ADS)

Gemmer, John; Sharon, Eran; Shearman, Toby; Venkataramani, Shankar C.

2016-04-01

The edges of torn plastic sheets and growing leaves often display hierarchical buckling patterns. We show that this complex morphology i) emerges even in zero strain configurations, and ii) is driven by a competition between the two principal curvatures, rather than between bending and stretching. We identify the key role of branch point (or “monkey saddle”) singularities in generating complex wrinkling patterns in isometric immersions, and show how they arise naturally from minimizing the elastic energy.

10 CFR 20.1406 - Minimization of contamination.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Minimization of contamination. 20.1406 Section 20.1406 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiological Criteria for License Termination § 20.1406 Minimization of contamination. (a) Applicants for licenses, other than early...

10 CFR 20.1406 - Minimization of contamination.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Minimization of contamination. 20.1406 Section 20.1406 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiological Criteria for License Termination § 20.1406 Minimization of contamination. (a) Applicants for licenses, other than early...

Deterministic and stochastic algorithms for resolving the flow fields in ducts and networks using energy minimization

NASA Astrophysics Data System (ADS)

Sochi, Taha

2016-09-01

Several deterministic and stochastic multi-variable global optimization algorithms (Conjugate Gradient, Nelder-Mead, Quasi-Newton and global) are investigated in conjunction with energy minimization principle to resolve the pressure and volumetric flow rate fields in single ducts and networks of interconnected ducts. The algorithms are tested with seven types of fluid: Newtonian, power law, Bingham, Herschel-Bulkley, Ellis, Ree-Eyring and Casson. The results obtained from all those algorithms for all these types of fluid agree very well with the analytically derived solutions as obtained from the traditional methods which are based on the conservation principles and fluid constitutive relations. The results confirm and generalize the findings of our previous investigations that the energy minimization principle is at the heart of the flow dynamics systems. The investigation also enriches the methods of computational fluid dynamics for solving the flow fields in tubes and networks for various types of Newtonian and non-Newtonian fluids.

Renewable Energy Technical Potential | Geospatial Data Science | NREL

Science.gov Websites

Technical Potential Renewable Energy Technical Potential The renewable energy technical potential level from Resource to Technical to Economic to Market. The benefit of assessing technical potential is potential-resource, technical, economic, and market-as shown in the graphic with key assumptions. Technical

Cost minimization in a full-scale conventional wastewater treatment plant: associated costs of biological energy consumption versus sludge production.

PubMed

Sid, S; Volant, A; Lesage, G; Heran, M

2017-11-01

Energy consumption and sludge production minimization represent rising challenges for wastewater treatment plants (WWTPs). The goal of this study is to investigate how energy is consumed throughout the whole plant and how operating conditions affect this energy demand. A WWTP based on the activated sludge process was selected as a case study. Simulations were performed using a pre-compiled model implemented in GPS-X simulation software. Model validation was carried out by comparing experimental and modeling data of the dynamic behavior of the mixed liquor suspended solids (MLSS) concentration and nitrogen compounds concentration, energy consumption for aeration, mixing and sludge treatment and annual sludge production over a three year exercise. In this plant, the energy required for bioreactor aeration was calculated at approximately 44% of the total energy demand. A cost optimization strategy was applied by varying the MLSS concentrations (from 1 to 8 gTSS/L) while recording energy consumption, sludge production and effluent quality. An increase of MLSS led to an increase of the oxygen requirement for biomass aeration, but it also reduced total sludge production. Results permit identification of a key MLSS concentration allowing identification of the best compromise between levels of treatment required, biological energy demand and sludge production while minimizing the overall costs.

Minimally Invasive Surgical Pulmonary Embolectomy: A Potential Alternative to Conventional Sternotomy.

PubMed

Pasrija, Chetan; Shah, Aakash; Sultanik, Elliot; Rouse, Michael; Ghoreishi, Mehrdad; Bittle, Gregory J; Boulos, Francesca; Griffith, Bartley P; Kon, Zachary N

Surgical pulmonary embolectomy has gained increasing popularity over the past decade with multiple series reporting excellent outcomes in the treatment of submassive pulmonary embolism. However, a significant barrier to the broader adoption of surgical pulmonary embolectomy remains the large incision and long recovery after a full sternotomy. We report the safety and efficacy of using a minimally invasive approach to surgical pulmonary embolectomy. All consecutive patients undergoing surgical pulmonary embolectomy for a submassive pulmonary embolism (2015-2017) were reviewed. Patients were stratified as conventional or minimally invasive. The minimally invasive approach included a 5- to 7-cm skin incision with upper hemisternotomy to the third intercostal space. The primary outcomes were in-hospital and 90-day survival. Thirty patients (conventional = 20, minimally invasive = 10) were identified. Operative time was similar between the two groups, but cardiopulmonary bypass time was significantly longer in the minimally invasive group (58 vs 94 minutes, P = 0.04). While ventilator time and intensive care unit length of stay were similar between groups, hospital length of stay was 4.5 days shorter in the minimally invasive group, and there was a trend toward less blood product use. In-hospital and 90-day survival was 100%. Within the minimally invasive cohort, median right ventricular dysfunction at discharge was none-mild and no patient experienced postoperative renal failure, deep sternal wound infection, sepsis, or stroke. Minimally invasive surgical pulmonary embolectomy appears to be a feasible approach in the treatment of patients with a submassive pulmonary embolism. A larger, prospective analysis comparing this modality with conventional surgical pulmonary embolectomy may be warranted.

Gravitational potential as a source of earthquake energy

USGS Publications Warehouse

Barrows, L.; Langer, C.J.

1981-01-01

Some degree of tectonic stress within the earth originates from gravity acting upon density structures. The work performed by this "gravitational tectonics stress" must have formerly existed as gravitational potential energy contained in the stress-causing density structure. According to the elastic rebound theory (Reid, 1910), the energy of earthquakes comes from an elastic strain field built up by fairly continuous elastic deformation in the period between events. For earthquakes resulting from gravitational tectonic stress, the elastic rebound theory requires the transfer of energy from the gravitational potential of the density structures into an elastic strain field prior to the event. An alternate theory involves partial gravitational collapse of the stress-causing density structures. The earthquake energy comes directly from a net decrease in gravitational potential energy. The gravitational potential energy released at the time of the earthquake is split between the energy released by the earthquake, including work done in the fault zone and an increase in stored elastic strain energy. The stress associated with this elastic strain field should oppose further fault slip. ?? 1981.

Global optimization of additive potential energy functions: Predicting binary Lennard-Jones clusters

NASA Astrophysics Data System (ADS)

Kolossváry, István; Bowers, Kevin J.

2010-11-01

We present a method for minimizing additive potential-energy functions. Our hidden-force algorithm can be described as an intricate multiplayer tug-of-war game in which teams try to break an impasse by randomly assigning some players to drop their ropes while the others are still tugging until a partial impasse is reached, then, instructing the dropouts to resume tugging, for all teams to come to a new overall impasse. Utilizing our algorithm in a non-Markovian parallel Monte Carlo search, we found 17 new putative global minima for binary Lennard-Jones clusters in the size range of 90-100 particles. The method is efficient enough that an unbiased search was possible; no potential-energy surface symmetries were exploited. All new minima are comprised of three nested polyicosahedral or polytetrahedral shells when viewed as a nested set of Connolly surfaces (though the shell structure has previously gone unscrutinized, known minima are often qualitatively similar). Unlike known minima, in which the outer and inner shells are comprised of the larger and smaller atoms, respectively, in 13 of the new minima, the atoms are not as clearly separated by size. Furthermore, while some known minima have inner shells stabilized by larger atoms, four of the new minima have outer shells stabilized by smaller atoms.

Renewable Energy Economic Potential | Geospatial Data Science | NREL

Science.gov Websites

Economic Potential Renewable Energy Economic Potential Economic potential, one measure of renewable electricity is less than the revenue available. Illustration that shows economic potential grow smaller at each level from Resource to Technical to Economic to Market. Estimating Renewable Energy Economic

Modeling specific action potentials in the human atria based on a minimal single-cell model.

PubMed

Richter, Yvonne; Lind, Pedro G; Maass, Philipp

2018-01-01

We present an effective method to model empirical action potentials of specific patients in the human atria based on the minimal model of Bueno-Orovio, Cherry and Fenton adapted to atrial electrophysiology. In this model, three ionic are currents introduced, where each of it is governed by a characteristic time scale. By applying a nonlinear optimization procedure, a best combination of the respective time scales is determined, which allows one to reproduce specific action potentials with a given amplitude, width and shape. Possible applications for supporting clinical diagnosis are pointed out.

Hack's relation and optimal channel networks: The elongation of river basins as a consequence of energy minimization

NASA Astrophysics Data System (ADS)

Ijjasz-Vasquez, Ede J.; Bras, Rafael L.; Rodriguez-Iturbe, Ignacio

1993-08-01

As pointed by Hack (1957), river basins tend to become longer and narrower as their size increases. This work shows that this property may be partially regarded as the consequence of competition and minimization of energy expenditure in river basins.

Reduced impact logging minimally alters tropical rainforest carbon and energy exchange.

PubMed

Miller, Scott D; Goulden, Michael L; Hutyra, Lucy R; Keller, Michael; Saleska, Scott R; Wofsy, Steven C; Figueira, Adelaine Michela Silva; da Rocha, Humberto R; de Camargo, Plinio B

2011-11-29

We used eddy covariance and ecological measurements to investigate the effects of reduced impact logging (RIL) on an old-growth Amazonian forest. Logging caused small decreases in gross primary production, leaf production, and latent heat flux, which were roughly proportional to canopy loss, and increases in heterotrophic respiration, tree mortality, and wood production. The net effect of RIL was transient, and treatment effects were barely discernable after only 1 y. RIL appears to provide a strategy for managing tropical forest that minimizes the potential risks to climate associated with large changes in carbon and water exchange.

Reduced impact logging minimally alters tropical rainforest carbon and energy exchange

PubMed Central

Miller, Scott D.; Goulden, Michael L.; Hutyra, Lucy R.; Keller, Michael; Saleska, Scott R.; Wofsy, Steven C.; Figueira, Adelaine Michela Silva; da Rocha, Humberto R.; de Camargo, Plinio B.

2011-01-01

We used eddy covariance and ecological measurements to investigate the effects of reduced impact logging (RIL) on an old-growth Amazonian forest. Logging caused small decreases in gross primary production, leaf production, and latent heat flux, which were roughly proportional to canopy loss, and increases in heterotrophic respiration, tree mortality, and wood production. The net effect of RIL was transient, and treatment effects were barely discernable after only 1 y. RIL appears to provide a strategy for managing tropical forest that minimizes the potential risks to climate associated with large changes in carbon and water exchange. PMID:22087005

Food waste minimization from a life-cycle perspective.

PubMed

Bernstad Saraiva Schott, A; Andersson, T

2015-01-01

This article investigates potentials and environmental impacts related to household food waste minimization, based on a case study in Southern Sweden. In the study, the amount of avoidable and unavoidable food waste currently being disposed of by households was assessed through waste composition analyses and the different types of avoidable food waste were classified. Currently, both avoidable and unavoidable food waste is either incinerated or treated through anaerobic digestion. A hypothetical scenario with no generation of avoidable food waste and either anaerobic digestion or incineration of unavoidable food waste was compared to the current situation using the life-cycle assessment method, limited to analysis of global warming potential (GWP). The results from the waste composition analyses indicate that an average of 35% of household food waste is avoidable. Minimization of this waste could result in reduction of greenhouse gas emissions of 800-1400 kg/tonne of avoidable food waste. Thus, a minimization strategy would result in increased avoidance of GWP compared to the current situation. The study clearly shows that although modern alternatives for food waste treatment can result in avoidance of GWP through nutrient and energy recovery, food waste prevention yields far greater benefits for GWP compared to both incineration and anaerobic digestion. Copyright © 2014 Elsevier Ltd. All rights reserved.

Minimal Model of Quantum Kinetic Clusters for the Energy-Transfer Network of a Light-Harvesting Protein Complex.

PubMed

Wu, Jianlan; Tang, Zhoufei; Gong, Zhihao; Cao, Jianshu; Mukamel, Shaul

2015-04-02

The energy absorbed in a light-harvesting protein complex is often transferred collectively through aggregated chromophore clusters. For population evolution of chromophores, the time-integrated effective rate matrix allows us to construct quantum kinetic clusters quantitatively and determine the reduced cluster-cluster transfer rates systematically, thus defining a minimal model of energy-transfer kinetics. For Fenna-Matthews-Olson (FMO) and light-havrvesting complex II (LCHII) monomers, quantum Markovian kinetics of clusters can accurately reproduce the overall energy-transfer process in the long-time scale. The dominant energy-transfer pathways are identified in the picture of aggregated clusters. The chromophores distributed extensively in various clusters can assist a fast and long-range energy transfer.

Action Potential Energy Efficiency Varies Among Neuron Types in Vertebrates and Invertebrates

PubMed Central

Sengupta, Biswa; Stemmler, Martin; Laughlin, Simon B.; Niven, Jeremy E.

2010-01-01

The initiation and propagation of action potentials (APs) places high demands on the energetic resources of neural tissue. Each AP forces ATP-driven ion pumps to work harder to restore the ionic concentration gradients, thus consuming more energy. Here, we ask whether the ionic currents underlying the AP can be predicted theoretically from the principle of minimum energy consumption. A long-held supposition that APs are energetically wasteful, based on theoretical analysis of the squid giant axon AP, has recently been overturned by studies that measured the currents contributing to the AP in several mammalian neurons. In the single compartment models studied here, AP energy consumption varies greatly among vertebrate and invertebrate neurons, with several mammalian neuron models using close to the capacitive minimum of energy needed. Strikingly, energy consumption can increase by more than ten-fold simply by changing the overlap of the Na+ and K+ currents during the AP without changing the APs shape. As a consequence, the height and width of the AP are poor predictors of energy consumption. In the Hodgkin–Huxley model of the squid axon, optimizing the kinetics or number of Na+ and K+ channels can whittle down the number of ATP molecules needed for each AP by a factor of four. In contrast to the squid AP, the temporal profile of the currents underlying APs of some mammalian neurons are nearly perfectly matched to the optimized properties of ionic conductances so as to minimize the ATP cost. PMID:20617202

Action potential energy efficiency varies among neuron types in vertebrates and invertebrates.

PubMed

Sengupta, Biswa; Stemmler, Martin; Laughlin, Simon B; Niven, Jeremy E

2010-07-01

The initiation and propagation of action potentials (APs) places high demands on the energetic resources of neural tissue. Each AP forces ATP-driven ion pumps to work harder to restore the ionic concentration gradients, thus consuming more energy. Here, we ask whether the ionic currents underlying the AP can be predicted theoretically from the principle of minimum energy consumption. A long-held supposition that APs are energetically wasteful, based on theoretical analysis of the squid giant axon AP, has recently been overturned by studies that measured the currents contributing to the AP in several mammalian neurons. In the single compartment models studied here, AP energy consumption varies greatly among vertebrate and invertebrate neurons, with several mammalian neuron models using close to the capacitive minimum of energy needed. Strikingly, energy consumption can increase by more than ten-fold simply by changing the overlap of the Na(+) and K(+) currents during the AP without changing the APs shape. As a consequence, the height and width of the AP are poor predictors of energy consumption. In the Hodgkin-Huxley model of the squid axon, optimizing the kinetics or number of Na(+) and K(+) channels can whittle down the number of ATP molecules needed for each AP by a factor of four. In contrast to the squid AP, the temporal profile of the currents underlying APs of some mammalian neurons are nearly perfectly matched to the optimized properties of ionic conductances so as to minimize the ATP cost.

Minimal non-abelian supersymmetric Twin Higgs

DOE PAGES

Badziak, Marcin; Harigaya, Keisuke

2017-10-17

We propose a minimal supersymmetric Twin Higgs model that can accommodate tuning of the electroweak scale for heavy stops better than 10% with high mediation scales of supersymmetry breaking. A crucial ingredient of this model is a new SU(2) X gauge symmetry which provides a D-term potential that generates a large SU(4) invariant coupling for the Higgs sector and only small set of particles charged under SU(2) X , which allows the model to be perturbative around the Planck scale. The new gauge interaction drives the top yukawa coupling small at higher energy scales, which also reduces the tuning.

Constraints on B and Higgs physics in minimal low energy supersymmetric models

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

Carena, Marcela; /Fermilab; Menon, A.

2006-03-01

We study the implications of minimal flavor violating low energy supersymmetry scenarios for the search of new physics in the B and Higgs sectors at the Tevatron collider and the LHC. We show that the already stringent Tevatron bound on the decay rate B{sub s} {yields} {mu}{sup +}{mu}{sup -} sets strong constraints on the possibility of generating large corrections to the mass difference {Delta} M{sub s} of the B{sub s} eigenstates. We also show that the B{sub s} {yields} {mu}{sup +}{mu}{sup -} bound together with the constraint on the branching ratio of the rare decay b {yields} s{gamma} has strongmore » implications for the search of light, non-standard Higgs bosons at hadron colliders. In doing this, we demonstrate that the former expressions derived for the analysis of the double penguin contributions in the Kaon sector need to be corrected by additional terms for a realistic analysis of these effects. We also study a specific non-minimal flavor violating scenario, where there are flavor changing gluino-squark-quark interactions, governed by the CKM matrix elements, and show that the B and Higgs physics constraints are similar to the ones in the minimal flavor violating case. Finally we show that, in scenarios like electroweak baryogenesis which have light stops and charginos, there may be enhanced effects on the B and K mixing parameters, without any significant effect on the rate of B{sub s} {yields} {mu}{sup +}{mu}{sup -}.« less

Thermal energy storage to minimize cost and improve efficiency of a polygeneration district energy system in a real-time electricity market

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

Powell, Kody M.; Kim, Jong Suk; Cole, Wesley J.

2016-10-01

District energy systems can produce low-cost utilities for large energy networks, but can also be a resource for the electric grid by their ability to ramp production or to store thermal energy by responding to real-time market signals. In this work, dynamic optimization exploits the flexibility of thermal energy storage by determining optimal times to store and extract excess energy. This concept is applied to a polygeneration distributed energy system with combined heat and power, district heating, district cooling, and chilled water thermal energy storage. The system is a university campus responsible for meeting the energy needs of tens ofmore » thousands of people. The objective for the dynamic optimization problem is to minimize cost over a 24-h period while meeting multiple loads in real time. The paper presents a novel algorithm to solve this dynamic optimization problem with energy storage by decomposing the problem into multiple static mixed-integer nonlinear programming (MINLP) problems. Another innovative feature of this work is the study of a large, complex energy network which includes the interrelations of a wide variety of energy technologies. Results indicate that a cost savings of 16.5% is realized when the system can participate in the wholesale electricity market.« less

Elucidating Molecular Motion through Structural and Dynamic Filters of Energy-Minimized Conformer Ensembles

PubMed Central

2015-01-01

Complex RNA structures are constructed from helical segments connected by flexible loops that move spontaneously and in response to binding of small molecule ligands and proteins. Understanding the conformational variability of RNA requires the characterization of the coupled time evolution of interconnected flexible domains. To elucidate the collective molecular motions and explore the conformational landscape of the HIV-1 TAR RNA, we describe a new methodology that utilizes energy-minimized structures generated by the program “Fragment Assembly of RNA with Full-Atom Refinement (FARFAR)”. We apply structural filters in the form of experimental residual dipolar couplings (RDCs) to select a subset of discrete energy-minimized conformers and carry out principal component analyses (PCA) to corroborate the choice of the filtered subset. We use this subset of structures to calculate solution T1 and T1ρ relaxation times for 13C spins in multiple residues in different domains of the molecule using two simulation protocols that we previously published. We match the experimental T1 times to within 2% and the T1ρ times to within less than 10% for helical residues. These results introduce a protocol to construct viable dynamic trajectories for RNA molecules that accord well with experimental NMR data and support the notion that the motions of the helical portions of this small RNA can be described by a relatively small number of discrete conformations exchanging over time scales longer than 1 μs. PMID:24479561

A potential energy surface for the process H2 + H2O yielding H + H + H2O - Ab initio calculations and analytical representation

NASA Technical Reports Server (NTRS)

Schwenke, David W.; Walch, Stephen P.; Taylor, Peter R.

1991-01-01

Extensive ab initio calculations on the ground state potential energy surface of H2 + H2O were performed using a large contracted Gaussian basis set and a high level of correlation treatment. An analytical representation of the potential energy surface was then obtained which reproduces the calculated energies with an overall root-mean-square error of only 0.64 mEh. The analytic representation explicitly includes all nine internal degrees of freedom and is also well behaved as the H2 dissociates; it thus can be used to study collision-induced dissociation or recombination of H2. The strategy used to minimize the number of energy calculations is discussed, as well as other advantages of the present method for determining the analytical representation.

Bandwidth Study on Energy Use and Potential Energy Savings Opportunities in U.S. Petroleum Refining

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

Sabine Brueske, Caroline Kramer, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. petroleum refining. The study relies on multiple sources to estimate the energy used in nine individual process areas, representing 68% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

The exponentiated Hencky-logarithmic strain energy. Part II: Coercivity, planar polyconvexity and existence of minimizers

NASA Astrophysics Data System (ADS)

Neff, Patrizio; Lankeit, Johannes; Ghiba, Ionel-Dumitrel; Martin, Robert; Steigmann, David

2015-08-01

We consider a family of isotropic volumetric-isochoric decoupled strain energies based on the Hencky-logarithmic (true, natural) strain tensor log U, where μ > 0 is the infinitesimal shear modulus, is the infinitesimal bulk modulus with the first Lamé constant, are dimensionless parameters, is the gradient of deformation, is the right stretch tensor and is the deviatoric part (the projection onto the traceless tensors) of the strain tensor log U. For small elastic strains, the energies reduce to first order to the classical quadratic Hencky energy which is known to be not rank-one convex. The main result in this paper is that in plane elastostatics the energies of the family are polyconvex for , extending a previous finding on its rank-one convexity. Our method uses a judicious application of Steigmann's polyconvexity criteria based on the representation of the energy in terms of the principal invariants of the stretch tensor U. These energies also satisfy suitable growth and coercivity conditions. We formulate the equilibrium equations, and we prove the existence of minimizers by the direct methods of the calculus of variations.

Improved Potential Energy Surface of Ozone Constructed Using the Fitting by Permutationally Invariant Polynomial Function

DOE PAGES

Ayouz, Mehdi; Babikov, Dmitri

2012-01-01

New global potential energy surface for the ground electronic state of ozone is constructed at the complete basis set level of the multireference configuration interaction theory. A method of fitting the data points by analytical permutationally invariant polynomial function is adopted. A small set of 500 points is preoptimized using the old surface of ozone. In this procedure the positions of points in the configuration space are chosen such that the RMS deviation of the fit is minimized. New ab initio calculations are carried out at these points and are used to build new surface. Additional points are added tomore » the vicinity of the minimum energy path in order to improve accuracy of the fit, particularly in the region where the surface of ozone exhibits a shallow van der Waals well. New surface can be used to study formation of ozone at thermal energies and its spectroscopy near the dissociation threshold.« less

Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Chemical Manufacturing

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

Sabine Brueske, Caroline Kramer, Aaron Fisher

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. chemical manufacturing. The study relies on multiple sources to estimate the energy used in the production of 74 individual chemicals, representing 57% of sector-wide energy consumption. Energy savings opportunities for individual chemicals and for 15 subsectors of chemicals manufacturing are based on technologies currently in use or under development; these potential savings are then extrapolated to estimate sector-wide energy savings opportunity.

Energy barriers, entropy barriers, and non-Arrhenius behavior in a minimal glassy model.

PubMed

Du, Xin; Weeks, Eric R

2016-06-01

We study glassy dynamics using a simulation of three soft Brownian particles confined to a two-dimensional circular region. If the circular region is large, the disks freely rearrange, but rearrangements are rarer for smaller system sizes. We directly measure a one-dimensional free-energy landscape characterizing the dynamics. This landscape has two local minima corresponding to the two distinct disk configurations, separated by a free-energy barrier that governs the rearrangement rate. We study several different interaction potentials and demonstrate that the free-energy barrier is composed of a potential-energy barrier and an entropic barrier. The heights of both of these barriers depend on temperature and system size, demonstrating how non-Arrhenius behavior can arise close to the glass transition.

Computed Potential Energy Surfaces and Minimum Energy Pathways for Chemical Reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

1994-01-01

Computed potential energy surfaces are often required for computation of such parameters as rate constants as a function of temperature, product branching ratios, and other detailed properties. For some dynamics methods, global potential energy surfaces are required. In this case, it is necessary to obtain the energy at a complete sampling of all the possible arrangements of the nuclei, which are energetically accessible, and then a fitting function must be obtained to interpolate between the computed points. In other cases, characterization of the stationary points and the reaction pathway connecting them is sufficient. These properties may be readily obtained using analytical derivative methods. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method to obtain accurate energetics, gives usefull results for a number of chemically important systems. The talk will focus on a number of applications including global potential energy surfaces, H + O2, H + N2, O(3p) + H2, and reaction pathways for complex reactions, including reactions leading to NO and soot formation in hydrocarbon combustion.

Timing of head movements is consistent with energy minimization in walking ungulates

PubMed Central

Loscher, David M.; Meyer, Fiete; Kracht, Kerstin

2016-01-01

Many ungulates show a conspicuous nodding motion of the head when walking. Until now, the functional significance of this behaviour remained unclear. Combining in vivo kinematics of quadrupedal mammals with a computer model, we show that the timing of vertical displacements of the head and neck is consistent with minimizing energy expenditure for carrying these body parts in an inverted pendulum walking gait. Varying the timing of head movements in the model resulted in increased metabolic cost estimate for carrying the head and neck of up to 63%. Oscillations of the head–neck unit result in weight force oscillations transmitted to the forelimbs. Advantageous timing increases the load in single support phases, in which redirecting the trajectory of the centre of mass (COM) is thought to be energetically inexpensive. During double support, in which—according to collision mechanics—directional changes of the impulse of the COM are expensive, the observed timing decreases the load. Because the head and neck comprise approximately 10% of body mass, the effect shown here should also affect the animals' overall energy expenditure. This mechanism, working analogously in high-tech backpacks for energy-saving load carriage, is widespread in ungulates, and provides insight into how animals economize locomotion. PMID:27903873

Energy potential of the modified excess sludge

NASA Astrophysics Data System (ADS)

Zawieja, Iwona

2017-11-01

On the basis of the SCOD value of excess sludge it is possible to estimate an amount of energy potentially obtained during the methane fermentation process. Based on a literature review, it has been estimated that from 1 kg of SCOD it is possible to obtain 3.48 kWh of energy. Taking into account the above methane and energy ratio (i.e. 10 kWh/1Nm3 CH4), it is possible to determine the volume of methane obtained from the tested sludge. Determination of potential energy of sludge is necessary for the use of biogas as a source of power generators as cogeneration and ensure the stability of this type of system. Therefore, the aim of the study was to determine the energy potential of excess sludge subjected to the thermal and chemical disintegration. In the case of thermal disintegration, test was conducted in the low temperature 80°C. The reagent used for the chemical modification was a peracetic acid, which in an aqueous medium having strong oxidizing properties. The time of chemical modification was 6 hours. Applied dose of the reagent was 1.0 ml CH3COOOH/L of sludge. By subjecting the sludge disintegration by the test methods achieved an increase in the SCOD value of modified sludge, indicating the improvement of biodegradability along with a concomitant increase in their energy potential. The obtained experimental production of biogas from disintegrated sludge confirmed that it is possible to estimate potential intensity of its production. The SCOD value of 2576 mg O2/L, in the case of chemical disintegration, was obtained for a dose of 1.0 ml CH3COOH/L. For this dose the pH value was equal 6.85. In the case of thermal disintegration maximum SCOD value was 2246 mg O2/L obtained at 80°C and the time of preparation 6 h. It was estimated that in case of thermal disintegration as well as for the chemical disintegration for selected parameters, the potential energy for model digester of active volume of 5L was, respectively, 0.193 and 0,118 kWh.

Geothermal Energy Potential in Western United States

ERIC Educational Resources Information Center

Pryde, Philip R.

1977-01-01

Reviews types of geothermal energy sources in the western states, including hot brine systems and dry steam systems. Conversion to electrical energy is a major potential use of geothermal energy, although it creates environmental disruptions such as noise, corrosion, and scaling of equipment. (AV)

Generalised teleparallel quintom dark energy non-minimally coupled with the scalar torsion and a boundary term

NASA Astrophysics Data System (ADS)

Bahamonde, Sebastian; Marciu, Mihai; Rudra, Prabir

2018-04-01

Within this work, we propose a new generalised quintom dark energy model in the teleparallel alternative of general relativity theory, by considering a non-minimal coupling between the scalar fields of a quintom model with the scalar torsion component T and the boundary term B. In the teleparallel alternative of general relativity theory, the boundary term represents the divergence of the torsion vector, B=2∇μTμ, and is related to the Ricci scalar R and the torsion scalar T, by the fundamental relation: R=‑T+B. We have investigated the dynamical properties of the present quintom scenario in the teleparallel alternative of general relativity theory by performing a dynamical system analysis in the case of decomposable exponential potentials. The study analysed the structure of the phase space, revealing the fundamental dynamical effects of the scalar torsion and boundary couplings in the case of a more general quintom scenario. Additionally, a numerical approach to the model is presented to analyse the cosmological evolution of the system.

Wind energy potential analysis in Al-Fattaih-Darnah

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

Tjahjana, Dominicus Danardono Dwi Prija, E-mail: danar1405@gmail.com; Salem, Abdelkarim Ali, E-mail: keemsalem@gmail.com; Himawanto, Dwi Aries, E-mail: dwiarieshimawanto@gmail.com

2016-03-29

In this paper the wind energy potential in Al-Fattaih-Darnah, Libya, had been studied. Wind energy is very attractive because it can provide a clean and renewable energy. Due mostly to the uncertainty caused by the chaotic characteristics of wind near the earth’s surface, wind energy characteristic need to be investigated carefully in order to get consistent power generation. This investigation was based on one year wind data measured in 2003. As a result of the analysis, wind speed profile and wind energy potential have been developed. The wind energy potential of the location is looked very promising to generate electricity.more » The annual wind speed of the site is 8.21 m/s and the wind speed carrying maximum energy is 7.97 m/s. The annual power density of the site is classified into class 3. The Polaris P50-500 wind turbine can produce 768.39 M Wh/year and has capacity factor of 17.54%.« less

Hydrogel-forming microneedle arrays: Potential for use in minimally-invasive lithium monitoring.

PubMed

Eltayib, Eyman; Brady, Aaron J; Caffarel-Salvador, Ester; Gonzalez-Vazquez, Patricia; Zaid Alkilani, Ahlam; McCarthy, Helen O; McElnay, James C; Donnelly, Ryan F

2016-05-01

We describe, for the first time, hydrogel-forming microneedle (s) (MN) arrays for minimally-invasive extraction and quantification of lithium in vitro and in vivo. MN arrays, prepared from aqueous blends of hydrolysed poly(methyl-vinylether-co-maleic anhydride) and crosslinked by poly(ethyleneglycol), imbibed interstitial fluid (ISF) upon skin insertion. Such MN were always removed intact. In vitro, mean detected lithium concentrations showed no significant difference following 30min MN application to excised neonatal porcine skin for lithium citrate concentrations of 0.9 and 2mmol/l. However, after 1h application, the mean lithium concentrations extracted were significantly different, being appropriately concentration-dependent. In vivo, rats were orally dosed with lithium citrate equivalent to 15mg/kg and 30mg/kg lithium carbonate, respectively. MN arrays were applied 1h after dosing and removed 1h later. The two groups, having received different doses, showed no significant difference between lithium concentrations in serum or MN. However, the higher dosed rats demonstrated a lithium concentration extracted from MN arrays equivalent to a mean increase of 22.5% compared to rats which received the lower dose. Hydrogel-forming MN clearly have potential as a minimally-invasive tool for lithium monitoring in outpatient settings. We will now focus on correlation between serum and MN lithium concentrations. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Assessing the Potential for Renewable Energy on Public Lands

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

Not Available

2003-02-01

This report represents an initial activity of the Bureau of Land Managements (BLM) proposed National Energy Policy Implementation Plan: identify and evaluate renewable energy resources on federal lands and any limitations on accessing them. Ultimately, BLM will prioritize land-use planning activities to increase industrys development of renewable energy resources. These resources include solar, biomass, geothermal, water, and wind energy. To accomplish this, BLM and the Department of Energys National Renewable Energy Laboratory (NREL) established a partnership to conduct an assessment of renewable energy resources on BLM lands in the western United States. The objective of this collaboration was to identifymore » BLM planning units in the western states with the highest potential for private-sector development of renewable resources. The assessment resulted in the following findings: (1) 63 BLM planning units in nine western states have high potential for one or more renewable energy technologies; and (2) 20 BLM planning units in seven western states have high potential for power production from three or more renewable energy sources. This assessment report provides BLM with information needed to prioritize land-use planning activities on the basis of potential for the development of energy from renewable resources.« less

Utilization of biocatalysts in cellulose waste minimization

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

Woodward, J.; Evans, B.R.

1996-09-01

Cellulose, a polymer of glucose, is the principal component of biomass and, therefore, a major source of waste that is either buried or burned. Examples of biomass waste include agricultural crop residues, forestry products, and municipal wastes. Recycling of this waste is important for energy conservation as well as waste minimization and there is some probability that in the future biomass could become a major energy source and replace fossil fuels that are currently used for fuels and chemicals production. It has been estimated that in the United States, between 100-450 million dry tons of agricultural waste are produced annually,more » approximately 6 million dry tons of animal waste, and of the 190 million tons of municipal solid waste (MSW) generated annually, approximately two-thirds is cellulosic in nature and over one-third is paper waste. Interestingly, more than 70% of MSW is landfilled or burned, however landfill space is becoming increasingly scarce. On a smaller scale, important cellulosic products such as cellulose acetate also present waste problems; an estimated 43 thousand tons of cellulose ester waste are generated annually in the United States. Biocatalysts could be used in cellulose waste minimization and this chapter describes their characteristics and potential in bioconversion and bioremediation processes.« less

Next-to-minimal SOFTSUSY

NASA Astrophysics Data System (ADS)

Allanach, B. C.; Athron, P.; Tunstall, Lewis C.; Voigt, A.; Williams, A. G.

2014-09-01

We describe an extension to the SOFTSUSY program that provides for the calculation of the sparticle spectrum in the Next-to-Minimal Supersymmetric Standard Model (NMSSM), where a chiral superfield that is a singlet of the Standard Model gauge group is added to the Minimal Supersymmetric Standard Model (MSSM) fields. Often, a Z3 symmetry is imposed upon the model. SOFTSUSY can calculate the spectrum in this case as well as the case where general Z3 violating (denoted as =) terms are added to the soft supersymmetry breaking terms and the superpotential. The user provides a theoretical boundary condition for the couplings and mass terms of the singlet. Radiative electroweak symmetry breaking data along with electroweak and CKM matrix data are used as weak-scale boundary conditions. The renormalisation group equations are solved numerically between the weak scale and a high energy scale using a nested iterative algorithm. This paper serves as a manual to the NMSSM mode of the program, detailing the approximations and conventions used. Catalogue identifier: ADPM_v4_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADPM_v4_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 154886 No. of bytes in distributed program, including test data, etc.: 1870890 Distribution format: tar.gz Programming language: C++, fortran. Computer: Personal computer. Operating system: Tested on Linux 3.x. Word size: 64 bits Classification: 11.1, 11.6. Does the new version supersede the previous version?: Yes Catalogue identifier of previous version: ADPM_v3_0 Journal reference of previous version: Comput. Phys. Comm. 183 (2012) 785 Nature of problem: Calculating supersymmetric particle spectrum and mixing parameters in the next-to-minimal supersymmetric standard model. The solution to the

Energies of Screened Coulomb Potentials.

ERIC Educational Resources Information Center

Lai, C. S.

1979-01-01

This article shows that, by applying the Hellman-Feynman theorem alone to screened Coulomb potentials, the first four coefficients in the energy series in powers of the perturbation parameter can be obtained from the unperturbed Coulomb system. (Author/HM)

In vitro screening techniques for reactive metabolites for minimizing bioactivation potential in drug discovery.

PubMed

Prakash, Chandra; Sharma, Raman; Gleave, Michelle; Nedderman, Angus

2008-11-01

Drug induced toxicity remains one of the major reasons for failures of new pharmaceuticals, and for the withdrawal of approved drugs from the market. Efforts are being made to reduce attrition of drug candidates, and to minimize their bioactivation potential in the early stages of drug discovery in order to bring safer compounds to the market. Therefore, in addition to potency and selectivity; drug candidates are now selected on the basis of acceptable metabolism/toxicology profiles in preclinical species. To support this, new approaches have been developed, which include extensive in vitro methods using human and animal hepatic cellular and subcellular systems, recombinant human drug metabolizing enzymes, increased automation for higher-throughput screens, sensitive analytical technologies and in silico computational models to assess the metabolism aspects of the new chemical entities. By using these approaches many compounds that might have serious adverse reactions associated with them are effectively eliminated before reaching clinical trials, however some toxicities such as those caused by idiosyncratic responses, are not detected until a drug is in late stages of clinical trials or has become available to the market. One of the proposed mechanisms for the development of idiosyncratic drug toxicity is the bioactivation of drugs to form reactive metabolites by drug metabolizing enzymes. This review discusses the different approaches to, and benefits of using existing in vitro techniques, for the detection of reactive intermediates in order to minimize bioactivation potential in drug discovery.

MO-FG-204-01: Improved Noise Suppression for Dual-Energy CT Through Entropy Minimization

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

Petrongolo, M; Zhu, L

2015-06-15

Purpose: In dual energy CT (DECT), noise amplification during signal decomposition significantly limits the utility of basis material images. Since clinically relevant objects contain a limited number of materials, we propose to suppress noise for DECT based on image entropy minimization. An adaptive weighting scheme is employed during noise suppression to improve decomposition accuracy with limited effect on spatial resolution and image texture preservation. Methods: From decomposed images, we first generate a 2D plot of scattered data points, using basis material densities as coordinates. Data points representing the same material generate a highly asymmetric cluster. We orient an axis bymore » minimizing the entropy in a 1D histogram of these points projected onto the axis. To suppress noise, we replace pixel values of decomposed images with center-of-mass values in the direction perpendicular to the optimal axis. To limit errors due to cluster overlap, we weight each data point’s contribution based on its high and low energy CT values and location within the image. The proposed method’s performance is assessed on physical phantom studies. Electron density is used as the quality metric for decomposition accuracy. Our results are compared to those without noise suppression and with a recently developed iterative method. Results: The proposed method reduces noise standard deviations of the decomposed images by at least one order of magnitude. On the Catphan phantom, this method greatly preserves the spatial resolution and texture of the CT images and limits induced error in measured electron density to below 1.2%. In the head phantom study, the proposed method performs the best in retaining fine, intricate structures. Conclusion: The entropy minimization based algorithm with adaptive weighting substantially reduces DECT noise while preserving image spatial resolution and texture. Future investigations will include extensive investigations on material

A Localization-Free Interference and Energy Holes Minimization Routing for Underwater Wireless Sensor Networks.

PubMed

Khan, Anwar; Ahmedy, Ismail; Anisi, Mohammad Hossein; Javaid, Nadeem; Ali, Ihsan; Khan, Nawsher; Alsaqer, Mohammed; Mahmood, Hasan

2018-01-09

Interference and energy holes formation in underwater wireless sensor networks (UWSNs) threaten the reliable delivery of data packets from a source to a destination. Interference also causes inefficient utilization of the limited battery power of the sensor nodes in that more power is consumed in the retransmission of the lost packets. Energy holes are dead nodes close to the surface of water, and their early death interrupts data delivery even when the network has live nodes. This paper proposes a localization-free interference and energy holes minimization (LF-IEHM) routing protocol for UWSNs. The proposed algorithm overcomes interference during data packet forwarding by defining a unique packet holding time for every sensor node. The energy holes formation is mitigated by a variable transmission range of the sensor nodes. As compared to the conventional routing protocols, the proposed protocol does not require the localization information of the sensor nodes, which is cumbersome and difficult to obtain, as nodes change their positions with water currents. Simulation results show superior performance of the proposed scheme in terms of packets received at the final destination and end-to-end delay.

A Localization-Free Interference and Energy Holes Minimization Routing for Underwater Wireless Sensor Networks

PubMed Central

Khan, Anwar; Anisi, Mohammad Hossein; Javaid, Nadeem; Khan, Nawsher; Alsaqer, Mohammed; Mahmood, Hasan

2018-01-01

Interference and energy holes formation in underwater wireless sensor networks (UWSNs) threaten the reliable delivery of data packets from a source to a destination. Interference also causes inefficient utilization of the limited battery power of the sensor nodes in that more power is consumed in the retransmission of the lost packets. Energy holes are dead nodes close to the surface of water, and their early death interrupts data delivery even when the network has live nodes. This paper proposes a localization-free interference and energy holes minimization (LF-IEHM) routing protocol for UWSNs. The proposed algorithm overcomes interference during data packet forwarding by defining a unique packet holding time for every sensor node. The energy holes formation is mitigated by a variable transmission range of the sensor nodes. As compared to the conventional routing protocols, the proposed protocol does not require the localization information of the sensor nodes, which is cumbersome and difficult to obtain, as nodes change their positions with water currents. Simulation results show superior performance of the proposed scheme in terms of packets received at the final destination and end-to-end delay. PMID:29315247

Optimal Control of Induction Machines to Minimize Transient Energy Losses

NASA Astrophysics Data System (ADS)

Plathottam, Siby Jose

Induction machines are electromechanical energy conversion devices comprised of a stator and a rotor. Torque is generated due to the interaction between the rotating magnetic field from the stator, and the current induced in the rotor conductors. Their speed and torque output can be precisely controlled by manipulating the magnitude, frequency, and phase of the three input sinusoidal voltage waveforms. Their ruggedness, low cost, and high efficiency have made them ubiquitous component of nearly every industrial application. Thus, even a small improvement in their energy efficient tend to give a large amount of electrical energy savings over the lifetime of the machine. Hence, increasing energy efficiency (reducing energy losses) in induction machines is a constrained optimization problem that has attracted attention from researchers. The energy conversion efficiency of induction machines depends on both the speed-torque operating point, as well as the input voltage waveform. It also depends on whether the machine is in the transient or steady state. Maximizing energy efficiency during steady state is a Static Optimization problem, that has been extensively studied, with commercial solutions available. On the other hand, improving energy efficiency during transients is a Dynamic Optimization problem that is sparsely studied. This dissertation exclusively focuses on improving energy efficiency during transients. This dissertation treats the transient energy loss minimization problem as an optimal control problem which consists of a dynamic model of the machine, and a cost functional. The rotor field oriented current fed model of the induction machine is selected as the dynamic model. The rotor speed and rotor d-axis flux are the state variables in the dynamic model. The stator currents referred to as d-and q-axis currents are the control inputs. A cost functional is proposed that assigns a cost to both the energy losses in the induction machine, as well as the

Free energy calculations: an efficient adaptive biasing potential method.

PubMed

Dickson, Bradley M; Legoll, Frédéric; Lelièvre, Tony; Stoltz, Gabriel; Fleurat-Lessard, Paul

2010-05-06

We develop an efficient sampling and free energy calculation technique within the adaptive biasing potential (ABP) framework. By mollifying the density of states we obtain an approximate free energy and an adaptive bias potential that is computed directly from the population along the coordinates of the free energy. Because of the mollifier, the bias potential is "nonlocal", and its gradient admits a simple analytic expression. A single observation of the reaction coordinate can thus be used to update the approximate free energy at every point within a neighborhood of the observation. This greatly reduces the equilibration time of the adaptive bias potential. This approximation introduces two parameters: strength of mollification and the zero of energy of the bias potential. While we observe that the approximate free energy is a very good estimate of the actual free energy for a large range of mollification strength, we demonstrate that the errors associated with the mollification may be removed via deconvolution. The zero of energy of the bias potential, which is easy to choose, influences the speed of convergence but not the limiting accuracy. This method is simple to apply to free energy or mean force computation in multiple dimensions and does not involve second derivatives of the reaction coordinates, matrix manipulations nor on-the-fly adaptation of parameters. For the alanine dipeptide test case, the new method is found to gain as much as a factor of 10 in efficiency as compared to two basic implementations of the adaptive biasing force methods, and it is shown to be as efficient as well-tempered metadynamics with the postprocess deconvolution giving a clear advantage to the mollified density of states method.

Minimization of the energy loss of nuclear power plants in case of partial in-core monitoring system failure

NASA Astrophysics Data System (ADS)

Zagrebaev, A. M.; Ramazanov, R. N.; Lunegova, E. A.

2017-01-01

In this paper we consider the optimization problem minimize of the energy loss of nuclear power plants in case of partial in-core monitoring system failure. It is possible to continuation of reactor operation at reduced power or total replacement of the channel neutron measurements, requiring shutdown of the reactor and the stock of detectors. This article examines the reconstruction of the energy release in the core of a nuclear reactor on the basis of the indications of height sensors. The missing measurement information can be reconstructed by mathematical methods, and replacement of the failed sensors can be avoided. It is suggested that a set of ‘natural’ functions determined by means of statistical estimates obtained from archival data be constructed. The procedure proposed makes it possible to reconstruct the field even with a significant loss of measurement information. Improving the accuracy of the restoration of the neutron flux density in partial loss of measurement information to minimize the stock of necessary components and the associated losses.

Predicting and mapping potential Whooping Crane stopover habitat to guide site selection for wind energy projects.

PubMed

Belaire, J Amy; Kreakie, Betty J; Keitt, Timothy; Minor, Emily

2014-04-01

Migratory stopover habitats are often not part of planning for conservation or new development projects. We identified potential stopover habitats within an avian migratory flyway and demonstrated how this information can guide the site-selection process for new development. We used the random forests modeling approach to map the distribution of predicted stopover habitat for the Whooping Crane (Grus americana), an endangered species whose migratory flyway overlaps with an area where wind energy development is expected to become increasingly important. We then used this information to identify areas for potential wind power development in a U.S. state within the flyway (Nebraska) that minimize conflicts between Whooping Crane stopover habitat and the development of clean, renewable energy sources. Up to 54% of our study area was predicted to be unsuitable as Whooping Crane stopover habitat and could be considered relatively low risk for conflicts between Whooping Cranes and wind energy development. We suggest that this type of analysis be incorporated into the habitat conservation planning process in areas where incidental take permits are being considered for Whooping Cranes or other species of concern. Field surveys should always be conducted prior to construction to verify model predictions and understand baseline conditions. © 2013 Society for Conservation Biology.

Ab Initio Potential Energy Surface for H-H2

NASA Technical Reports Server (NTRS)

Patridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

1993-01-01

Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- 3 micro E(h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces (25-70 kcal/mol above the H-H2 asymptote) at small interatomic separations; the Boothroyd, Keogh, Martin, and Peterson (BKMP) potential energy surface is found to agree with results of the present calculations within the expected uncertainty (+/- 1 kcal/mol) of the fit. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(0)) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

Potential for energy recovery from humid air streams.

Treesearch

Howard H. Rosen

1979-01-01

The potential for energy recovery from the vent stream of dryers is examined by assuming the vent stream transfers its energy in a regenerative heat exchanger. Tables present energy recovery over a range of conditions. Example problems demonstrate the use of the energy recovery tables.

Research on potential user identification model for electric energy substitution

NASA Astrophysics Data System (ADS)

Xia, Huaijian; Chen, Meiling; Lin, Haiying; Yang, Shuo; Miao, Bo; Zhu, Xinzhi

2018-01-01

The implementation of energy substitution plays an important role in promoting the development of energy conservation and emission reduction in china. Energy service management platform of alternative energy users based on the data in the enterprise production value, product output, coal and other energy consumption as a potential evaluation index, using principal component analysis model to simplify the formation of characteristic index, comprehensive index contains the original variables, and using fuzzy clustering model for the same industry user’s flexible classification. The comprehensive index number and user clustering classification based on constructed particle optimization neural network classification model based on the user, user can replace electric potential prediction. The results of an example show that the model can effectively predict the potential of users’ energy potential.

Spin–orbit coupling, minimal model and potential Cooper-pairing from repulsion in BiS2-superconductors

NASA Astrophysics Data System (ADS)

Cobo-Lopez, Sergio; Saeed Bahramy, Mohammad; Arita, Ryotaro; Akbari, Alireza; Eremin, Ilya

2018-04-01

We develop the realistic minimal electronic model for recently discovered BiS2 superconductors including the spin–orbit (SO) coupling based on the first-principles band structure calculations. Due to strong SO coupling, characteristic for the Bi-based systems, the tight-binding low-energy model necessarily includes p x , p y , and p z orbitals. We analyze a potential Cooper-pairing instability from purely repulsive interaction for the moderate electronic correlations using the so-called leading angular harmonics approximation. For small and intermediate doping concentrations we find the dominant instabilities to be {d}{x2-{y}2}-wave, and s ±-wave symmetries, respectively. At the same time, in the absence of the sizable spin fluctuations the intra and interband Coulomb repulsions are of the same strength, which yield the strongly anisotropic behavior of the superconducting gaps on the Fermi surface. This agrees with recent angle resolved photoemission spectroscopy findings. In addition, we find that the Fermi surface topology for BiS2 layered systems at large electron doping can resemble the doped iron-based pnictide superconductors with electron and hole Fermi surfaces maintaining sufficient nesting between them. This could provide further boost to increase T c in these systems.

The extended Lennard-Jones potential energy function: A simpler model for direct-potential-fit analysis

NASA Astrophysics Data System (ADS)

Hajigeorgiou, Photos G.

2016-12-01

An analytical model for the diatomic potential energy function that was recently tested as a universal function (Hajigeorgiou, 2010) has been further modified and tested as a suitable model for direct-potential-fit analysis. Applications are presented for the ground electronic states of three diatomic molecules: oxygen, carbon monoxide, and hydrogen fluoride. The adjustable parameters of the extended Lennard-Jones potential model are determined through nonlinear regression by fits to calculated rovibrational energy term values or experimental spectroscopic line positions. The model is shown to lead to reliable, compact and simple representations for the potential energy functions of these systems and could therefore be classified as a suitable and attractive model for direct-potential-fit analysis.

Properties of Augmented Kohn-Sham Potential for Energy as Simple Sum of Orbital Energies.

PubMed

Zahariev, Federico; Levy, Mel

2017-01-12

A recent modification to the traditional Kohn-Sham method ( Levy , M. ; Zahariev , F. Phys. Rev. Lett. 2014 , 113 , 113002 ; Levy , M. ; Zahariev , F. Mol. Phys. 2016 , 114 , 1162 - 1164 ), which gives the ground-state energy as a direct sum of the occupied orbital energies, is discussed and its properties are numerically illustrated on representative atoms and ions. It is observed that current approximate density functionals tend to give surprisingly small errors for the highest occupied orbital energies that are obtained with the augmented potential. The appropriately shifted Kohn-Sham potential is the basic object within this direct-energy Kohn-Sham method and needs to be approximated. To facilitate approximations, several constraints to the augmented Kohn-Sham potential are presented.

Inflationary predictions of double-well, Coleman-Weinberg, and hilltop potentials with non-minimal coupling

NASA Astrophysics Data System (ADS)

Bostan, Nilay; Güleryüz, Ömer; Nefer Şenoğuz, Vedat

2018-05-01

We discuss how the non-minimal coupling ξphi2R between the inflaton and the Ricci scalar affects the predictions of single field inflation models where the inflaton has a non-zero vacuum expectation value (VEV) v after inflation. We show that, for inflaton values both above the VEV and below the VEV during inflation, under certain conditions the inflationary predictions become approximately the same as the predictions of the Starobinsky model. We then analyze inflation with double-well and Coleman-Weinberg potentials in detail, displaying the regions in the v-ξ plane for which the spectral index ns and the tensor-to-scalar ratio r values are compatible with the current observations. r is always larger than 0.002 in these regions. Finally, we consider the effect of ξ on small field inflation (hilltop) potentials.

EPA RE-Powering Mapper: Alternative Energy Potential at Cleanup Sites

EPA Pesticide Factsheets

The U.S. Environmental Protection Agency (EPA) Office of Land and Emergency Management??s (OLEM) Office of Communications, Partnerships and Analysis (OCPA) initiated the RE-Powering America's Land Initiative to demonstrate the enormous potential that contaminated lands, landfills, and mine sites provide for developing renewable energy in the United States. EPA developed national level site screening criteria in partnership with the U.S. Department of Energy (DOE) National Renewable Energy Laboratory (NREL) for wind, solar, biomass, and geothermal facilities. While the screening criteria demonstrate the potential to reuse contaminated land for renewable energy facilities, the criteria and data are neither designed to identify the best sites for developing renewable energy nor all-inclusive. Therefore, more detailed, site-specific analysis is necessary to identify or prioritize the best sites for developing renewable energy facilities based on the technical and economic potential. Please note that these sites were only pre-screened for renewable energy potential. The sites were not evaluated for land use constraints or current on the ground conditions. Additional research and site-specific analysis are needed to verify viability for renewable energy potential at a given site.

NEUTRON ENERGY LEVELS IN A DIFFUSE POTENTIAL

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

Ghosh, A.; Sil, N.C.

1960-06-01

The energy eigenvalues of neutrons within the nucleus for a spherically symmetrical potential V(r) = --V/sub 0/STAl + exp{(r-- R)/a}!/sup -1/ are investigated by following a new method of Lanczos for solving the differential equation. The s- and p-state energy levels are calculated for atomic mass 200 with the values of parameters adopted by Feshbach et al. in their calculation of the neutron strength function with a similar potential. The results of the calculation agree closely with those of Malenka. (auth)

Bandwidth Study on Energy Use and Potential Energy Saving Opportunities in U.S. Pulp and Paper Manufacturing

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

Sabine Brueske, Caroline Kramer, Aaron Fisher

2015-06-01

Energy bandwidth studies of U.S. manufacturing sectors can serve as foundational references in framing the range (or bandwidth) of potential energy savings opportunities. This bandwidth study examines energy consumption and potential energy savings opportunities in U.S. pulp and paper manufacturing. The study relies on multiple sources to estimate the energy used in six individual process areas, representing 52% of sector-wide energy consumption. Energy savings opportunities for individual processes are based on technologies currently in use or under development; the potential savings are then extrapolated to estimate sector-wide energy savings opportunity

Life cycle optimization model for integrated cogeneration and energy systems applications in buildings

NASA Astrophysics Data System (ADS)

Osman, Ayat E.

Energy use in commercial buildings constitutes a major proportion of the energy consumption and anthropogenic emissions in the USA. Cogeneration systems offer an opportunity to meet a building's electrical and thermal demands from a single energy source. To answer the question of what is the most beneficial and cost effective energy source(s) that can be used to meet the energy demands of the building, optimizations techniques have been implemented in some studies to find the optimum energy system based on reducing cost and maximizing revenues. Due to the significant environmental impacts that can result from meeting the energy demands in buildings, building design should incorporate environmental criteria in the decision making criteria. The objective of this research is to develop a framework and model to optimize a building's operation by integrating congregation systems and utility systems in order to meet the electrical, heating, and cooling demand by considering the potential life cycle environmental impact that might result from meeting those demands as well as the economical implications. Two LCA Optimization models have been developed within a framework that uses hourly building energy data, life cycle assessment (LCA), and mixed-integer linear programming (MILP). The objective functions that are used in the formulation of the problems include: (1) Minimizing life cycle primary energy consumption, (2) Minimizing global warming potential, (3) Minimizing tropospheric ozone precursor potential, (4) Minimizing acidification potential, (5) Minimizing NOx, SO 2 and CO2, and (6) Minimizing life cycle costs, considering a study period of ten years and the lifetime of equipment. The two LCA optimization models can be used for: (a) long term planning and operational analysis in buildings by analyzing the hourly energy use of a building during a day and (b) design and quick analysis of building operation based on periodic analysis of energy use of a building in a

Ab initio Potential Energy Surface for H-H2

NASA Technical Reports Server (NTRS)

Partridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

1993-01-01

Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- (mu)E(sub h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(sub 0) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

Manufacturing of mushroom-shaped structures and its hydrophobic robustness analysis based on energy minimization approach

NASA Astrophysics Data System (ADS)

Wang, Li; Yang, Xiaonan; Wang, Quandai; Yang, Zhiqiang; Duan, Hui; Lu, Bingheng

2017-07-01

The construction of stable hydrophobic surfaces has increasingly gained attention owing to its wide range of potential applications. However, these surfaces may become wet and lose their slip effect owing to insufficient hydrophobic stability. Pillars with a mushroom-shaped tip are believed to enhance hydrophobicity stability. This work presents a facile method of manufacturing mushroom-shaped structures, where, compared with the previously used method, the modulation of the cap thickness, cap diameter, and stem height of the structures is more convenient. The effects of the development time on the cap diameter and overhanging angle are investigated and well-defined mushroom-shaped structures are demonstrated. The effect of the microstructure geometry on the contact state of a droplet is predicted by taking an energy minimization approach and is experimentally validated with nonvolatile ultraviolet-curable polymer with a low surface tension by inspecting the profiles of liquid-vapor interface deformation and tracking the trace of the receding contact line after exposure to ultraviolet light. Theoretical and experimental results show that, compared with regular pillar arrays having a vertical sidewall, the mushroom-like structures can effectively enhance hydrophobic stability. The proposed manufacturing method will be useful for fabricating robust hydrophobic surfaces in a cost-effective and convenient manner.

The Dilemmas of Energy: Essential energy services and potentially fatal risks

NASA Astrophysics Data System (ADS)

Perkins, J. H.

2018-01-01

During their evolution, humans have made three energy transitions, each marked by the adoption of new ways of procuring energy with attendant changes in lifestyle. Modern civilization arose in the Third Energy Transition, and its major sources of energy come from coal, oil, gas, uranium, and hydropower. Unfortunately, despite its incalculable benefits, the Third Transition can’t provide sustainable energy services for the indefinite future. Climate change is the most serious problem. Criteria and standards for each of the currently available, nine primary energy sources indicate the potential feasibility of replacing most or all uses of coal, oil, gas, and uranium with hydropower, solar, wind, biomass, and geothermal. This is the Fourth Energy Transition, promotion of which is strongly supported by considerations of sustainability.

The potential energy landscape contribution to the dynamic heat capacity

NASA Astrophysics Data System (ADS)

Brown, Jonathan R.; McCoy, John D.

2011-05-01

The dynamic heat capacity of a simple polymeric, model glassformer was computed using molecular dynamics simulations by sinusoidally driving the temperature and recording the resultant energy. The underlying potential energy landscape of the system was probed by taking a time series of particle positions and quenching them. The resulting dynamic heat capacity demonstrates that the long time relaxation is the direct result of dynamics resulting from the potential energy landscape. Moreover, the equilibrium (low frequency) portion of the potential energy landscape contribution to the heat capacity is found to increase rapidly at low temperatures and at high packing fractions. This increase in the heat capacity is explained by a statistical mechanical model based on the distribution of minima in the potential energy landscape.

Pressure-strain energy redistribution in compressible turbulence: return-to-isotropy versus kinetic-potential energy equipartition

NASA Astrophysics Data System (ADS)

Lee, Kurnchul; Venugopal, Vishnu; Girimaji, Sharath S.

2016-08-01

Return-to-isotropy and kinetic-potential energy equipartition are two fundamental pressure-moderated energy redistributive processes in anisotropic compressible turbulence. Pressure-strain correlation tensor redistributes energy among various Reynolds stress components and pressure-dilatation is responsible for energy reallocation between dilatational kinetic and potential energies. The competition and interplay between these pressure-based processes are investigated in this study. Direct numerical simulations (DNS) of low turbulent Mach number dilatational turbulence are performed employing the hybrid thermal Lattice Boltzman method (HTLBM). It is found that a tendency towards equipartition precedes proclivity for isotropization. An evolution towards equipartition has a collateral but critical effect on return-to-isotropy. The preferential transfer of energy from strong (rather than weak) Reynolds stress components to potential energy accelerates the isotropization of dilatational fluctuations. Understanding of these pressure-based redistributive processes is critical for developing insight into the character of compressible turbulence.

Minimally invasive periodontal therapy

PubMed Central

Dannan, Aous

2011-01-01

Minimally invasive dentistry is a concept that preserves dentition and supporting structures. However, minimally invasive procedures in periodontal treatment are supposed to be limited within periodontal surgery, the aim of which is to represent alternative approaches developed to allow less extensive manipulation of surrounding tissues than conventional procedures, while accomplishing the same objectives. In this review, the concept of minimally invasive periodontal surgery (MIPS) is firstly explained. An electronic search for all studies regarding efficacy and effectiveness of MIPS between 2001 and 2009 was conducted. For this purpose, suitable key words from Medical Subject Headings on PubMed were used to extract the required studies. All studies are demonstrated and important results are concluded. Preliminary data from case cohorts and from many studies reveal that the microsurgical access flap, in terms of MIPS, has a high potential to seal the healing wound from the contaminated oral environment by achieving and maintaining primary closure. Soft tissues are mostly preserved and minimal gingival recession is observed, an important feature to meet the demands of the patient and the clinician in the esthetic zone. However, although the potential efficacy of MIPS in the treatment of deep intrabony defects has been proved, larger studies are required to confirm and extend the reported positive preliminary outcomes. PMID:22368356

Re-examining Potential for Geothermal Energy in United States

NASA Astrophysics Data System (ADS)

Showstack, Randy

New technological initiatives, along with potential policy and economic incentives, could help to bring about a resurgence in geothermal energy development in the United States, said several experts at a 22 May forum in Washington, D.C. The forum was sponsored by the House and Senate Renewable Energy and Energy Efficiency Caucuses, the Sustainable Energy Coalition, and the Environmental and Energy Study Institute. Among these initiatives is an ambitious program of the U.S. Department of Energy to expand existing geothermal energy fields and potentially create new fields through ``enhanced geothermal systems.'' In addition, a program of the Bush administration encourages geothermal development on some public lands, and current legislation would provide tax credits and other incentives for geothermal development.

Potential of energy production from conserved forages

USDA-ARS?s Scientific Manuscript database

Forages have a potential role in meeting the demand for energy. Perennial forages are attractive for various reasons. One, both the monetary and energy cost of planting is spread over many years. Two, we already have the equipment for harvesting, storing and transporting this source of biomass. Thre...

The minimal axion minimal linear σ model

NASA Astrophysics Data System (ADS)

Merlo, L.; Pobbe, F.; Rigolin, S.

2018-05-01

The minimal SO(5) / SO(4) linear σ model is extended including an additional complex scalar field, singlet under the global SO(5) and the Standard Model gauge symmetries. The presence of this scalar field creates the conditions to generate an axion à la KSVZ, providing a solution to the strong CP problem, or an axion-like-particle. Different choices for the PQ charges are possible and lead to physically distinct Lagrangians. The internal consistency of each model necessarily requires the study of the scalar potential describing the SO(5)→ SO(4), electroweak and PQ symmetry breaking. A single minimal scenario is identified and the associated scalar potential is minimised including counterterms needed to ensure one-loop renormalizability. In the allowed parameter space, phenomenological features of the scalar degrees of freedom, of the exotic fermions and of the axion are illustrated. Two distinct possibilities for the axion arise: either it is a QCD axion with an associated scale larger than ˜ 105 TeV and therefore falling in the category of the invisible axions; or it is a more massive axion-like-particle, such as a 1 GeV axion with an associated scale of ˜ 200 TeV, that may show up in collider searches.

Use of Binary Partition Tree and energy minimization for object-based classification of urban land cover

NASA Astrophysics Data System (ADS)

Li, Mengmeng; Bijker, Wietske; Stein, Alfred

2015-04-01

Two main challenges are faced when classifying urban land cover from very high resolution satellite images: obtaining an optimal image segmentation and distinguishing buildings from other man-made objects. For optimal segmentation, this work proposes a hierarchical representation of an image by means of a Binary Partition Tree (BPT) and an unsupervised evaluation of image segmentations by energy minimization. For building extraction, we apply fuzzy sets to create a fuzzy landscape of shadows which in turn involves a two-step procedure. The first step is a preliminarily image classification at a fine segmentation level to generate vegetation and shadow information. The second step models the directional relationship between building and shadow objects to extract building information at the optimal segmentation level. We conducted the experiments on two datasets of Pléiades images from Wuhan City, China. To demonstrate its performance, the proposed classification is compared at the optimal segmentation level with Maximum Likelihood Classification and Support Vector Machine classification. The results show that the proposed classification produced the highest overall accuracies and kappa coefficients, and the smallest over-classification and under-classification geometric errors. We conclude first that integrating BPT with energy minimization offers an effective means for image segmentation. Second, we conclude that the directional relationship between building and shadow objects represented by a fuzzy landscape is important for building extraction.

Analysis on Potential of Electric Energy Market based on Large Industrial Consumer

NASA Astrophysics Data System (ADS)

Lin, Jingyi; Zhu, Xinzhi; Yang, Shuo; Xia, Huaijian; Yang, Di; Li, Hao; Lin, Haiying

2018-01-01

The implementation of electric energy substitution by enterprises plays an important role in promoting the development of energy conservation and emission reduction in china. In order to explore alternative energy potential of industrial enterprises, to simulate and analyze the process of industrial enterprises, identify high energy consumption process and equipment, give priority to alternative energy technologies, and determine the enterprise electric energy substitution potential predictive value, this paper constructs the evaluation model of the influence factors of the electric energy substitution potential of industrial enterprises, and uses the combined weight method to determine the weight value of the evaluation factors to calculate the target value of the electric energy substitution potential. Taking the iron and steel industry as an example, this method is used to excavate the potential. The results show that the method can effectively tap the potential of the electric power industry

Eigensolutions, Shannon entropy and information energy for modified Tietz-Hua potential

NASA Astrophysics Data System (ADS)

Onate, C. A.; Onyeaju, M. C.; Ituen, E. E.; Ikot, A. N.; Ebomwonyi, O.; Okoro, J. O.; Dopamu, K. O.

2018-04-01

The Tietz-Hua potential is modified by the inclusion of De ( {{Ch - 1}/{1 - C_{h e^{{ - bh ( {r - re } )}} }}} )be^{{ - bh ( {r - re } )}} term to the Tietz-Hua potential model since a potential of such type is very good in the description and vibrational energy levels for diatomic molecules. The energy eigenvalues and the corresponding eigenfunctions are explicitly obtained using the methodology of parametric Nikiforov-Uvarov. By putting the potential parameter b = 0, in the modified Tietz-Hua potential quickly reduces to the Tietz-Hua potential. To show more applications of our work, we have computed the Shannon entropy and Information energy under the modified Tietz-Hua potential. However, the computation of the Shannon entropy and Information energy is an extension of the work of Falaye et al., who computed only the Fisher information under Tietz-Hua potential.

Green Energy in New Construction: Maximize Energy Savings and Minimize Cost

ERIC Educational Resources Information Center

Ventresca, Joseph

2010-01-01

People often use the term "green energy" to refer to alternative energy technologies. But green energy doesn't guarantee maximum energy savings at a minimum cost--a common misconception. For school business officials, green energy means getting the lowest energy bills for the lowest construction cost, which translates into maximizing green energy…

Energy Minimization of Discrete Protein Titration State Models Using Graph Theory.

PubMed

Purvine, Emilie; Monson, Kyle; Jurrus, Elizabeth; Star, Keith; Baker, Nathan A

2016-08-25

There are several applications in computational biophysics that require the optimization of discrete interacting states, for example, amino acid titration states, ligand oxidation states, or discrete rotamer angles. Such optimization can be very time-consuming as it scales exponentially in the number of sites to be optimized. In this paper, we describe a new polynomial time algorithm for optimization of discrete states in macromolecular systems. This algorithm was adapted from image processing and uses techniques from discrete mathematics and graph theory to restate the optimization problem in terms of "maximum flow-minimum cut" graph analysis. The interaction energy graph, a graph in which vertices (amino acids) and edges (interactions) are weighted with their respective energies, is transformed into a flow network in which the value of the minimum cut in the network equals the minimum free energy of the protein and the cut itself encodes the state that achieves the minimum free energy. Because of its deterministic nature and polynomial time performance, this algorithm has the potential to allow for the ionization state of larger proteins to be discovered.

Energy Minimization of Discrete Protein Titration State Models Using Graph Theory

PubMed Central

Purvine, Emilie; Monson, Kyle; Jurrus, Elizabeth; Star, Keith; Baker, Nathan A.

2016-01-01

There are several applications in computational biophysics which require the optimization of discrete interacting states; e.g., amino acid titration states, ligand oxidation states, or discrete rotamer angles. Such optimization can be very time-consuming as it scales exponentially in the number of sites to be optimized. In this paper, we describe a new polynomial-time algorithm for optimization of discrete states in macromolecular systems. This algorithm was adapted from image processing and uses techniques from discrete mathematics and graph theory to restate the optimization problem in terms of “maximum flow-minimum cut” graph analysis. The interaction energy graph, a graph in which vertices (amino acids) and edges (interactions) are weighted with their respective energies, is transformed into a flow network in which the value of the minimum cut in the network equals the minimum free energy of the protein, and the cut itself encodes the state that achieves the minimum free energy. Because of its deterministic nature and polynomial-time performance, this algorithm has the potential to allow for the ionization state of larger proteins to be discovered. PMID:27089174

Free Energy Computations by Minimization of Kullback-Leibler Divergence: An Efficient Adaptive Biasing Potential Method for Sparse Representations

DTIC Science & Technology

2011-10-14

landscapes. It is motivated by statistical learning arguments and unifies the tasks of biasing the molecular dynamics to escape free energy wells and...statistical learning arguments and unifies the tasks of biasing the molecular dynamics to escape free energy wells and estimating the free energy...experimentally, to characterize global changes as well as investigate relative stabilities. In most applications, a brute- force computation based on

Controlling molecular transport in minimal emulsions

NASA Astrophysics Data System (ADS)

Gruner, Philipp; Riechers, Birte; Semin, Benoît; Lim, Jiseok; Johnston, Abigail; Short, Kathleen; Baret, Jean-Christophe

2016-01-01

Emulsions are metastable dispersions in which molecular transport is a major mechanism driving the system towards its state of minimal energy. Determining the underlying mechanisms of molecular transport between droplets is challenging due to the complexity of a typical emulsion system. Here we introduce the concept of `minimal emulsions', which are controlled emulsions produced using microfluidic tools, simplifying an emulsion down to its minimal set of relevant parameters. We use these minimal emulsions to unravel the fundamentals of transport of small organic molecules in water-in-fluorinated-oil emulsions, a system of great interest for biotechnological applications. Our results are of practical relevance to guarantee a sustainable compartmentalization of compounds in droplet microreactors and to design new strategies for the dynamic control of droplet compositions.

The Potential for Harvesting Energy from the Movement of Trees

PubMed Central

McGarry, Scott; Knight, Chris

2011-01-01

Over the last decade, wireless devices have decreased in size and power requirements. These devices generally use batteries as a power source but can employ additional means of power, such as solar, thermal or wind energy. However, sensor networks are often deployed in conditions of minimal lighting and thermal gradient such as densely wooded environments, where even normal wind energy harvesting is limited. In these cases a possible source of energy is from the motion of the trees themselves. We investigated the amount of energy and power available from the motion of a tree in a sheltered position, during Beaufort 4 winds. We measured the work performed by the tree to lift a mass, we measured horizontal acceleration of free movement, and we determined the angular deflection of the movement of the tree trunk, to determine the energy and power available to various types of harvesting devices. We found that the amount of power available from the tree, as demonstrated by lifting a mass, compares favourably with the power required to run a wireless sensor node. PMID:22163695

The potential for harvesting energy from the movement of trees.

PubMed

McGarry, Scott; Knight, Chris

2011-01-01

Over the last decade, wireless devices have decreased in size and power requirements. These devices generally use batteries as a power source but can employ additional means of power, such as solar, thermal or wind energy. However, sensor networks are often deployed in conditions of minimal lighting and thermal gradient such as densely wooded environments, where even normal wind energy harvesting is limited. In these cases a possible source of energy is from the motion of the trees themselves. We investigated the amount of energy and power available from the motion of a tree in a sheltered position, during Beaufort 4 winds. We measured the work performed by the tree to lift a mass, we measured horizontal acceleration of free movement, and we determined the angular deflection of the movement of the tree trunk, to determine the energy and power available to various types of harvesting devices. We found that the amount of power available from the tree, as demonstrated by lifting a mass, compares favourably with the power required to run a wireless sensor node.

Principle of minimal work fluctuations.

PubMed

Xiao, Gaoyang; Gong, Jiangbin

2015-08-01

Understanding and manipulating work fluctuations in microscale and nanoscale systems are of both fundamental and practical interest. For example, in considering the Jarzynski equality 〈e-βW〉=e-βΔF, a change in the fluctuations of e-βW may impact how rapidly the statistical average of e-βW converges towards the theoretical value e-βΔF, where W is the work, β is the inverse temperature, and ΔF is the free energy difference between two equilibrium states. Motivated by our previous study aiming at the suppression of work fluctuations, here we obtain a principle of minimal work fluctuations. In brief, adiabatic processes as treated in quantum and classical adiabatic theorems yield the minimal fluctuations in e-βW. In the quantum domain, if a system initially prepared at thermal equilibrium is subjected to a work protocol but isolated from a bath during the time evolution, then a quantum adiabatic process without energy level crossing (or an assisted adiabatic process reaching the same final states as in a conventional adiabatic process) yields the minimal fluctuations in e-βW, where W is the quantum work defined by two energy measurements at the beginning and at the end of the process. In the classical domain where the classical work protocol is realizable by an adiabatic process, then the classical adiabatic process also yields the minimal fluctuations in e-βW. Numerical experiments based on a Landau-Zener process confirm our theory in the quantum domain, and our theory in the classical domain explains our previous numerical findings regarding the suppression of classical work fluctuations [G. Y. Xiao and J. B. Gong, Phys. Rev. E 90, 052132 (2014)].

Achieving wood energy potentials: evidence in northeastern Minnesota.

Treesearch

Dennis P. Bradley; David C. Lothner

1987-01-01

A study of wood energy potential in northeastern Minnesota concludes that (1) the forests of the region could support a much larger wood energy harvest without significant cost increases for other forest products; (2) existing stands are predominantly overmature and cutting more now will enhance future wood supplies for all users; (3) converting to wood energy could...

Non-minimally coupled quintessence dark energy model with a cubic galileon term: a dynamical system analysis

NASA Astrophysics Data System (ADS)

Bhattacharya, Somnath; Mukherjee, Pradip; Roy, Amit Singha; Saha, Anirban

2018-03-01

We consider a scalar field which is generally non-minimally coupled to gravity and has a characteristic cubic Galilean-like term and a generic self-interaction, as a candidate of a Dark Energy model. The system is dynamically analyzed and novel fixed points with perturbative stability are demonstrated. Evolution of the system is numerically studied near a novel fixed point which owes its existence to the Galileon character of the model. It turns out that demanding the stability of this novel fixed point puts a strong restriction on the allowed non-minimal coupling and the choice of the self-interaction. The evolution of the equation of state parameter is studied, which shows that our model predicts an accelerated universe throughout and the phantom limit is only approached closely but never crossed. Our result thus extends the findings of Coley, Dynamical systems and cosmology. Kluwer Academic Publishers, Boston (2013) for more general NMC than linear and quadratic couplings.

Warm Body Temperature Facilitates Energy Efficient Cortical Action Potentials

PubMed Central

Yu, Yuguo; Hill, Adam P.; McCormick, David A.

2012-01-01

The energy efficiency of neural signal transmission is important not only as a limiting factor in brain architecture, but it also influences the interpretation of functional brain imaging signals. Action potential generation in mammalian, versus invertebrate, axons is remarkably energy efficient. Here we demonstrate that this increase in energy efficiency is due largely to a warmer body temperature. Increases in temperature result in an exponential increase in energy efficiency for single action potentials by increasing the rate of Na+ channel inactivation, resulting in a marked reduction in overlap of the inward Na+, and outward K+, currents and a shortening of action potential duration. This increase in single spike efficiency is, however, counterbalanced by a temperature-dependent decrease in the amplitude and duration of the spike afterhyperpolarization, resulting in a nonlinear increase in the spike firing rate, particularly at temperatures above approximately 35°C. Interestingly, the total energy cost, as measured by the multiplication of total Na+ entry per spike and average firing rate in response to a constant input, reaches a global minimum between 37–42°C. Our results indicate that increases in temperature result in an unexpected increase in energy efficiency, especially near normal body temperature, thus allowing the brain to utilize an energy efficient neural code. PMID:22511855

Collective motion in prolate γ-rigid nuclei within minimal length concept via a quantum perturbation method

NASA Astrophysics Data System (ADS)

Chabab, M.; El Batoul, A.; Lahbas, A.; Oulne, M.

2018-05-01

Based on the minimal length concept, inspired by Heisenberg algebra, a closed analytical formula is derived for the energy spectrum of the prolate γ-rigid Bohr-Mottelson Hamiltonian of nuclei, within a quantum perturbation method (QPM), by considering a scaled Davidson potential in β shape variable. In the resulting solution, called X(3)-D-ML, the ground state and the first β-band are all studied as a function of the free parameters. The fact of introducing the minimal length concept with a QPM makes the model very flexible and a powerful approach to describe nuclear collective excitations of a variety of vibrational-like nuclei. The introduction of scaling parameters in the Davidson potential enables us to get a physical minimum of this latter in comparison with previous works. The analysis of the corrected wave function, as well as the probability density distribution, shows that the minimal length parameter has a physical upper bound limit.

Study of the potential of wave energy in Malaysia

NASA Astrophysics Data System (ADS)

Tan, Wan Ching; Chan, Keng Wai; Ooi, Heivin

2017-07-01

Renewable energy is generally defined as energy harnessed from resources which are naturally replenished. It is an alternative to the current conventional energy sources such as natural gas, oil and coal, which are nonrenewable. Besides being nonrenewable, the harnessing of these resources generally produce by-products which could be potentially harmful to the environment. On the contrary, the generation from renewable energy does not pose environmental degradation. Some examples of renewable energy sources are sunlight, wind, tides, waves and geothermal heat. Wave energy is considered as one of the most promising marine renewable resources and is becoming commercially viable quicker than other renewable technologies at an astonishing growth rate. This paper illustrates the working principle of wave energy converter (WEC) and the availability of wave energy in Malaysia oceans. A good understanding of the behaviour of ocean waves is important for designing an efficient WEC as the characteristics of the waves in shallow and deep water are different. Consequently, wave energy converters are categorized into three categories on shore, near shore and offshore. Therefore, the objectives of this study is ought to be carried out by focusing on the formation of waves and wave characteristics in shallow as well as in deep water. The potential sites for implementation of wave energy harvesting technology in Malaysia and the wave energy available in the respective area were analysed. The potential of wave energy in Malaysia were tabulated and presented with theoretical data. The interaction between motion of waves and heave buoys for optimum phase condition by using the mass and diameter as the variables were investigated.

Radio frequency energy for non-invasive and minimally invasive skin tightening.

PubMed

Mulholland, R Stephen

2011-07-01

This article reviews the non-invasive and minimally invasive options for skin tightening, focusing on peer-reviewed articles and presentations and those technologies with the most proven or promising RF non-excisional skin-tightening results for excisional surgeons. RF has been the mainstay of non-invasive skin tightening and has emerged as the "cutting edge" technology in the minimally invasive skin-tightening field. Because these RF skin-tightening technologies are capital equipment purchases with a significant cost associated, this article also discusses some business issues and models that have proven to work in the plastic surgeon's office for non-invasive and minimally invasive skin-tightening technologies. Copyright © 2011 Elsevier Inc. All rights reserved.

Direct computation of general chemical energy differences: Application to ionization potentials, excitation, and bond energies.

PubMed

Beste, A; Harrison, R J; Yanai, T

2006-08-21

Chemists are mainly interested in energy differences. In contrast, most quantum chemical methods yield the total energy which is a large number compared to the difference and has therefore to be computed to a higher relative precision than would be necessary for the difference alone. Hence, it is desirable to compute energy differences directly, thereby avoiding the precision problem. Whenever it is possible to find a parameter which transforms smoothly from an initial to a final state, the energy difference can be obtained by integrating the energy derivative with respect to that parameter (cf. thermodynamic integration or adiabatic connection methods). If the dependence on the parameter is predominantly linear, accurate results can be obtained by single-point integration. In density functional theory and Hartree-Fock, we applied the formalism to ionization potentials, excitation energies, and chemical bond breaking. Example calculations for ionization potentials and excitation energies showed that accurate results could be obtained with a linear estimate. For breaking bonds, we introduce a nongeometrical parameter which gradually turns the interaction between two fragments of a molecule on. The interaction changes the potentials used to determine the orbitals as well as the constraint on the orbitals to be orthogonal.

Potential energy hypersurface and molecular flexibility

NASA Astrophysics Data System (ADS)

Koča, Jaroslav

1993-02-01

The molecular flexibility phenomenon is discussed from the conformational potential energy(hyper) surface (PES) point of view. Flexibility is considered as a product of three terms: thermodynamic, kinetic and geometrical. Several expressions characterizing absolute and relative molecular flexibility are introduced, depending on a subspace studied of the entire conformational space, energy level E of PES as well as absolute temperature. Results obtained by programs DAISY, CICADA and PANIC in conjunction with molecular mechanics program MMX for flexibility analysis of isopentane, 2,2-dimethylpentane and isohexane molecules are introduced.

Potential for natural evaporation as a reliable renewable energy resource

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

Cavusoglu, Ahmet-Hamdi; Chen, Xi; Gentine, Pierre

About 50% of the solar energy absorbed at the Earth’s surface drives evaporation, fueling the water cycle that affects various renewable energy resources, such as wind and hydropower. Recent advances demonstrate our nascent ability to convert evaporation energy into work, yet there is little understanding about the potential of this resource. Here in this paper we study the energy available from natural evaporation to predict the potential of this ubiquitous resource. We find that natural evaporation from open water surfaces could provide power densities comparable to current wind and solar technologies while cutting evaporative water losses by nearly half. Wemore » estimate up to 325 GW of power is potentially available in the United States. Strikingly, water’s large heat capacity is sufficient to control power output by storing excess energy when demand is low, thus reducing intermittency and improving reliability. Our findings motivate the improvement of materials and devices that convert energy from evaporation.« less

Potential for natural evaporation as a reliable renewable energy resource

DOE PAGES

Cavusoglu, Ahmet-Hamdi; Chen, Xi; Gentine, Pierre; ...

2017-09-26

About 50% of the solar energy absorbed at the Earth’s surface drives evaporation, fueling the water cycle that affects various renewable energy resources, such as wind and hydropower. Recent advances demonstrate our nascent ability to convert evaporation energy into work, yet there is little understanding about the potential of this resource. Here in this paper we study the energy available from natural evaporation to predict the potential of this ubiquitous resource. We find that natural evaporation from open water surfaces could provide power densities comparable to current wind and solar technologies while cutting evaporative water losses by nearly half. Wemore » estimate up to 325 GW of power is potentially available in the United States. Strikingly, water’s large heat capacity is sufficient to control power output by storing excess energy when demand is low, thus reducing intermittency and improving reliability. Our findings motivate the improvement of materials and devices that convert energy from evaporation.« less

Energy Minimization of Discrete Protein Titration State Models Using Graph Theory

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

Purvine, Emilie AH; Monson, Kyle E.; Jurrus, Elizabeth R.

There are several applications in computational biophysics which require the optimization of discrete interacting states; e.g., amino acid titration states, ligand oxidation states, or discrete rotamer angles. Such optimization can be very time-consuming as it scales exponentially in the number of sites to be optimized. In this paper, we describe a new polynomial-time algorithm for optimization of discrete states in macromolecular systems. This algorithm was adapted from image processing and uses techniques from discrete mathematics and graph theory to restate the optimization problem in terms of maximum flow-minimum cut graph analysis. The interaction energy graph, a graph in which verticesmore » (amino acids) and edges (interactions) are weighted with their respective energies, is transformed into a flow network in which the value of the minimum cut in the network equals the minimum free energy of the protein, and the cut itself encodes the state that achieves the minimum free energy. Because of its deterministic nature and polynomial-time performance, this algorithm has the potential to allow for the ionization state of larger proteins to be discovered.« less

10 CFR 20.1406 - Minimization of contamination.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Minimization of contamination. 20.1406 Section 20.1406 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiological Criteria for..., including the subsurface, in accordance with the existing radiation protection requirements in Subpart B and...

10 CFR 20.1406 - Minimization of contamination.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Minimization of contamination. 20.1406 Section 20.1406 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiological Criteria for... subsurface, in accordance with the existing radiation protection requirements in subpart B and radiological...

10 CFR 20.1406 - Minimization of contamination.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Minimization of contamination. 20.1406 Section 20.1406 Energy NUCLEAR REGULATORY COMMISSION STANDARDS FOR PROTECTION AGAINST RADIATION Radiological Criteria for... subsurface, in accordance with the existing radiation protection requirements in subpart B and radiological...

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.

Energy consumption during simulated minimal access surgery with and without using an armrest.

PubMed

Jafri, Mansoor; Brown, Stuart; Arnold, Graham; Abboud, Rami; Wang, Weijie

2013-03-01

Minimal access surgery (MAS) can be a lengthy procedure when compared to open surgery and therefore surgeon fatigue becomes an important issue and surgeons may expose themselves to chronic injuries and making errors. There have been few studies on this topic and they have used only questionnaires and electromyography rather than direct measurement of energy expenditure (EE). The aim of this study was to investigate whether the use of an armrest could reduce the EE of surgeons during MAS. Sixteen surgeons performed simulated MAS with and without using an armrest. They were required to perform the time-consuming task of using scissors to cut a rubber glove through its top layer in a triangular fashion with the help of a laparoscopic camera. Energy consumptions were measured using the Oxycon Mobile system during all the procedures. Error rate and duration time for simulated surgery were recorded. After performing the simulated surgery, subjects scored how comfortable they felt using the armrest. It was found that O(2) uptake (VO(2)) was 5 % less when surgeons used the armrest. The error rate when performing the procedure with the armrest was 35 % compared with 42.29 % without the armrest. Additionally, comfort levels with the armrest were higher than without the armrest. 75 % of surgeons indicated a preference for using the armrest during the simulated surgery. The armrest provides support for surgeons and cuts energy consumption during simulated MAS.

Minimally displaced clavicle fracture after high-energy injury: are they likely to displace?

PubMed

Riehl, John T; Athans, Bill J; Munro, Mark W; Langford, Joshua R; Kupiszewski, Stanley J; Haidukewych, George J; Koval, Kenneth J

2014-06-01

Nondisplaced or minimally displaced clavicle fractures are often considered to be benign injuries. These fractures in the trauma patient population, however, may deserve closer follow-up than their low-energy counterparts. We sought to determine the initial assessment performed on these patients and the rate of subsequent fracture displacement in patients sustaining high-energy trauma when a supine chest radiograph on initial trauma survey revealed a well-aligned clavicle fracture. We retrospectively reviewed the cases of trauma alert patients who sustained a midshaft clavicle fracture (AO/OTA type 15-B) with less than 100% displacement treated at a single level 1 trauma centre between 2005 and 2010. We compared fracture displacement on initial supine chest radiographs and follow-up radiographs. Orthopedic consultation and the type of imaging studies obtained were also recorded. Ninety-five patients with clavicle fractures met the inclusion criteria. On follow-up, 57 (60.0%) had displacement of 100% or more of the shaft width. Most patients (63.2%) in our study had an orthopedic consultation during their hospital admission, and 27.4% had clavicle radiographs taken on the day of admission. Clavicle fractures in patients with a high-energy mechanism of injury are prone to fracture displacement, even when initial supine chest radiographs show nondisplacement. We recommend clavicle films as part of the initial evaluation for all patients with clavicle fractures and early follow-up within the first 2 weeks of injury.

Minimally displaced clavicle fracture after high-energy injury: Are they likely to displace?

PubMed Central

Riehl, John T.; Athans, Bill J.; Munro, Mark W.; Langford, Joshua R.; Kupiszewski, Stanley J.; Haidukewych, George J.; Koval, Kenneth J.

2014-01-01

Background Nondisplaced or minimally displaced clavicle fractures are often considered to be benign injuries. These fractures in the trauma patient population, however, may deserve closer follow-up than their low-energy counterparts. We sought to determine the initial assessment performed on these patients and the rate of subsequent fracture displacement in patients sustaining high-energy trauma when a supine chest radiograph on initial trauma survey revealed a well-aligned clavicle fracture. Methods We retrospectively reviewed the cases of trauma alert patients who sustained a midshaft clavicle fracture (AO/OTA type 15-B) with less than 100% displacement treated at a single level 1 trauma centre between 2005 and 2010. We compared fracture displacement on initial supine chest radiographs and follow-up radiographs. Orthopedic consultation and the type of imaging studies obtained were also recorded. Results Ninety-five patients with clavicle fractures met the inclusion criteria. On follow-up, 57 (60.0%) had displacement of 100% or more of the shaft width. Most patients (63.2%) in our study had an orthopedic consultation during their hospital admission, and 27.4% had clavicle radiographs taken on the day of admission. Conclusion Clavicle fractures in patients with a high-energy mechanism of injury are prone to fracture displacement, even when initial supine chest radiographs show nondisplacement. We recommend clavicle films as part of the initial evaluation for all patients with clavicle fractures and early follow-up within the first 2 weeks of injury. PMID:24869608

Convective Available Potential Energy of World Ocean

NASA Astrophysics Data System (ADS)

Su, Z.; Ingersoll, A. P.; Thompson, A. F.

2012-12-01

Here, for the first time, we propose the concept of Ocean Convective Available Potential Energy (OCAPE), which is the maximum kinetic energy (KE) per unit seawater mass achievable by ocean convection. OCAPE occurs through a different mechanism from atmospheric CAPE, and involves the interplay of temperature and salinity on the equation of state of seawater. The thermobaric effect, which arises because the thermal coefficient of expansion increases with depth, is an important ingredient of OCAPE. We develop an accurate algorithm to calculate the OCAPE for a given temperature and salinity profile. We then validate our calculation of OCAPE by comparing it with the conversion of OCAPE to KE in a 2-D numerical model. We propose that OCAPE is an important energy source of ocean deep convection and contributes to deep water formation. OCAPE, like Atmospheric CAPE, can help predict deep convection and may also provide a useful constraint for modelling deep convection in ocean GCMs. We plot the global distribution of OCAPE using data from the World Ocean Atlas 2009 (WOA09) and see many important features. These include large values of OCAPE in the Labrador, Greenland, Weddell and Mediterranean Seas, which are consistent with our present observations and understanding, but also identify some new features like the OCAPE pattern in the Antarctic Circumpolar Current (ACC). We propose that the diagnosis of OCAPE can improve our understanding of global patterns of ocean convection and deep water formation as well as ocean stratification, the meridional overturning circulation and mixed layer processes. The background of this work is briefly introduced as below. Open-ocean deep convection can significantly modify water properties both at the ocean surface and throughout the water column (Gordon 1982). Open-ocean convection is also an important mechanism for Ocean Deep Water formation and the transport of heat, freshwater and nutrient (Marshall and Schott 1999). Open

Teaching Potential Energy Functions and Stability with Slap Bracelets

NASA Astrophysics Data System (ADS)

Van Hook, Stephen J.

2005-10-01

The slap bracelet, an inexpensive child's toy, makes it easy to engage students in hands-on exploration of potential energy curves as well as of stable, unstable, and meta-stable states. Rather than just observing the teacher performing a demonstration, the students can manipulate the equipment themselves and make their own observations, which are then pooled to focus a class discussion on potential energy functions and stability.

Collecting and Analyzing At-Sea and Coastal Avian Data to Assess Potential Effects of Offshore Renewable Energy Development

NASA Astrophysics Data System (ADS)

Pereksta, D. M.

2016-02-01

The prospect of renewable energy development off the coasts of the United States has led to a scramble for data needs on potentially affected resources, particularly those related to avian species. The potential effects from renewable energy development to avian species are complex and varied including collision, displacement, barrier effects, and attraction. As the lead Federal agency for renewable energy development on the Federal outer continental shelf (OCS), the Bureau of Ocean Energy Management (BOEM) has initiated, in coordination with other agencies and partners, the collection and synthesizing of existing data, identification of data gaps, development and funding of studies to fill those gaps, and creation of products for assessing risk to birds from structures at sea. Through the Environmental Studies Program, BOEM collects a wide range of environmental information to provide an improved understanding of offshore ecosystems, a baseline for assessing cumulative effects, and the scientific basis for development of regulatory measures to mitigate adverse impacts. With broad-scale assessments of suitable areas for wind, wave, and tidal energy production offshore, the challenge has been to collect and compile information quickly and at as large a scale as possible. Assessing what we know, what we can predict, and how can we assess risk has led BOEM to develop and collaborate on a variety of studies including baseline data assessments, at-sea surveys, predictive modeling of seabird distribution and abundance, vulnerability and risk assessments, and technology testing for efficient ways to inventory birds on the OCS. These are being applied in both the Atlantic and Pacific, including the Main Hawaiian Islands, to provide for assessments of potential effects and data needs early in the planning process at regional and local scales with the goal of designing and implementing projects that will minimize effects to avian species to the greatest extent practicable.

Non-minimally coupled condensate cosmologies: a phase space analysis

NASA Astrophysics Data System (ADS)

Carloni, Sante; Vignolo, Stefano; Cianci, Roberto

2014-09-01

We present an analysis of the phase space of cosmological models based on a non-minimal coupling between the geometry and a fermionic condensate. We observe that the strong constraint coming from the Dirac equations allows a detailed design of the cosmology of these models, and at the same time guarantees an evolution towards a state indistinguishable from general relativistic cosmological models. In this light, we show in detail how the use of some specific potentials can naturally reproduce a phase of accelerated expansion. In particular, we find for the first time that an exponential potential is able to induce two de Sitter phases separated by a power law expansion, which could be an interesting model for the unification of an inflationary phase and a dark energy era.

Mass Energy Equivalence Formula Must Include Rotational and Vibrational Kinetuic Energies as Well As Potential Energies

NASA Astrophysics Data System (ADS)

Brekke, Stewart

2010-11-01

Originally Einstein proposed the the mass-energy equivalence at low speeds as E=mc^2 + 1/2 mv^2. However, a mass may also be rotating and vibrating as well as moving linearly. Although small, these kinetic energies must be included in formulating a true mathematical statement of the mass-energy equivalence. Also, gravitational, electromagneic and magnetic potential energies must be included in the mass-energy equivalence mathematical statement. While the kinetic energy factors may differ in each physical situation such as types of vibrations and rotations, the basic equation for the mass- energy equivalence is therefore E = m0c^2 + 1/2m0v^2 + 1/2I2̂+ 1/2kx^2 + WG+ WE+ WM.

Thermodynamic potential of free energy for thermo-elastic-plastic body

NASA Astrophysics Data System (ADS)

Śloderbach, Z.; Pająk, J.

2018-01-01

The procedure of derivation of thermodynamic potential of free energy (Helmholtz free energy) for a thermo-elastic-plastic body is presented. This procedure concerns a special thermodynamic model of a thermo-elastic-plastic body with isotropic hardening characteristics. The classical thermodynamics of irreversible processes for material characterized by macroscopic internal parameters is used in the derivation. Thermodynamic potential of free energy may be used for practical determination of the level of stored energy accumulated in material during plastic processing applied, e.g., for industry components and other machinery parts received by plastic deformation processing. In this paper the stored energy for the simple stretching of austenitic steel will be presented.

Potential energy surface of cyclooctatetraene

NASA Astrophysics Data System (ADS)

Andrés, José L.; Castaño, Obis; Morreale, Antonio; Palmeiro, Raul; Gomperts, Roberto

1998-01-01

We present a theoretical study of the cyclooctatetraene (COT) molecule. Seven COT structures are located on the singlet ground state potential energy surface. Four of them, which present D2d (tub), Cs (bicyclo[4.2.0]octa-2,4,7-triene or BOT), C2h (chair) and D4 (crown) symmetries are stable species, and the other three are transition state structures showing Cs, D4h, and D8h symmetry. We discuss the symmetry of wave functions for these stationary points. Geometries, energies, and harmonic vibrational frequencies of these structures, and energy gaps between singlet-triplet states and low-lying singlets are presented. For the planar D4h and D8h structures, Jahn-Teller and tunneling effects have also been discussed. Ring inversion, bond shifting and valence isomerization reactive channels from the tub COT conformer are discussed from the point of view of the corresponding transition state structures. Where possible, in order to lend support to this theoretical information comparisons with recent transition state spectroscopy data are made.

Energy-switching potential energy surface for ground-state C3

NASA Astrophysics Data System (ADS)

Rocha, C. M. R.; Varandas, A. J. C.

2018-05-01

The multiple energy switching scheme [J. Chem. Phys. 119 (2003) 2596] has been used to improve the double many-body expansion (DMBE II) potential energy surface of C3 near its linear global minima by morphing it with an accurate Taylor-series expansion [J. Chem. Phys. 144 (2016) 044307]. The final ES form attains the accuracy of the local form in reproducing the rovibrational spectrum of C3 while keeping unaltered all key attributes of the original DMBE II, namely conical intersection seams and dissociative channels. The ES form is therefore commended for adiabatic spectroscopic and reaction dynamics studies.

Labor management evidence update: potential to minimize risk of cesarean birth in healthy women.

PubMed

Simpson, Kathleen Rice

2014-01-01

New evidence regarding normal parameters of labor progress for healthy women has the potential to minimize risk of cesarean birth and thereby enhance current and future maternal well-being if clinicians apply the research findings to obstetric practice. The economic and reproductive health consequences of the increasing cesarean birth rate in the United States are considerable; therefore, action on this issue by all stakeholders is necessary. Review and integration of the recent recommendations for labor management from experts convened by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the American College of Obstetricians and Gynecologists, and the Society for Maternal-Fetal Medicine are required to make maternity care in the United States as safe as possible.

Potential for natural evaporation as a reliable renewable energy resource.

PubMed

Cavusoglu, Ahmet-Hamdi; Chen, Xi; Gentine, Pierre; Sahin, Ozgur

2017-09-26

About 50% of the solar energy absorbed at the Earth's surface drives evaporation, fueling the water cycle that affects various renewable energy resources, such as wind and hydropower. Recent advances demonstrate our nascent ability to convert evaporation energy into work, yet there is little understanding about the potential of this resource. Here we study the energy available from natural evaporation to predict the potential of this ubiquitous resource. We find that natural evaporation from open water surfaces could provide power densities comparable to current wind and solar technologies while cutting evaporative water losses by nearly half. We estimate up to 325 GW of power is potentially available in the United States. Strikingly, water's large heat capacity is sufficient to control power output by storing excess energy when demand is low, thus reducing intermittency and improving reliability. Our findings motivate the improvement of materials and devices that convert energy from evaporation.The evaporation of water represents an alternative source of renewable energy. Building on previous models of evaporation, Cavusoglu et al. show that the power available from this natural resource is comparable to wind and solar power, yet it does not suffer as much from varying weather conditions.

Possible explanation of the atmospheric kinetic and potential energy spectra.

PubMed

Vallgren, Andreas; Deusebio, Enrico; Lindborg, Erik

2011-12-23

We hypothesize that the observed wave number spectra of kinetic and potential energy in the atmosphere can be explained by assuming that there are two related cascade processes emanating from the same large-scale energy source, a downscale cascade of potential enstrophy, giving rise to the k(-3) spectrum at synoptic scales and a downscale energy cascade giving rise to the k(-5/3) spectrum at mesoscales. The amount of energy which is going into the downscale energy cascade is determined by the rate of system rotation, with negligible energy going downscale in the limit of very fast rotation. We present a set of simulations of a system with strong rotation and stratification, supporting these hypotheses and showing good agreement with observations.

Energy minimization in nematic liquid crystal systems driven by geometric confinement and temperature gradients with applications in colloidal systems

NASA Astrophysics Data System (ADS)

Kolacz, Jakub

We first explore the topology of liquid crystals and look at the fundamental limitations of liquid crystals in confined geometries. The properties of liquid crystal droplets are studied both theoretically and through simulations. We then demonstrate a method of chemically patterning surfaces that allows us to generate periodic arrays of micron-sized liquid crystal droplets and compare them to our simulation results. The parallelizable method of self-localizing liquid crystals using 2D chemical patterning developed here has applications in liquid crystal biosensors and lens arrays. We also present the first work looking at colloidal liquid crystals under the guise of thermophoresis. We observe that strong negative thermophoresis occurs in these systems and develop a theory based on elastic energy minimization. We also calculate a Soret coefficient two orders of magnitude larger than those present in the literature. This large Soret coefficient has considerable potential for improving thermophoretic sorting mechanisms such as Thermal-Field Flow Fractionation and MicroScale Thermophoresis. The final piece of this work demonstrates a method of using projection lithography to polymerize liquid crystal colloids with a defined internal director. While still a work in progress, there is potential for generating systems of active colloids that can change shape upon external stimulus and in the generation of self-folding shapes by selective polymerization and director predetermination in the vain of micro-kirigami.

Potential Energy Cost Savings from Increased Commercial Energy Code Compliance

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

Rosenberg, Michael I.; Hart, Philip R.; Athalye, Rahul A.

2016-08-22

An important question for commercial energy code compliance is: “How much energy cost savings can better compliance achieve?” This question is in sharp contrast to prior efforts that used a checklist of code requirements, each of which was graded pass or fail. Percent compliance for any given building was simply the percent of individual requirements that passed. A field investigation method is being developed that goes beyond the binary approach to determine how much energy cost savings is not realized. Prototype building simulations were used to estimate the energy cost impact of varying levels of non-compliance for newly constructed officemore » buildings in climate zone 4C. Field data collected from actual buildings on specific conditions relative to code requirements was then applied to the simulation results to find the potential lost energy savings for a single building or for a sample of buildings. This new methodology was tested on nine office buildings in climate zone 4C. The amount of additional energy cost savings they could have achieved had they complied fully with the 2012 International Energy Conservation Code is determined. This paper will present the results of the test, lessons learned, describe follow-on research that is needed to verify that the methodology is both accurate and practical, and discuss the benefits that might accrue if the method were widely adopted.« less

San Jose, California: Evaluating Local Solar Energy Generation Potential (City Energy: From Data to Decisions)

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

Office of Strategic Programs, Strategic Priorities and Impact Analysis Team

This fact sheet "San Jose, California: Evaluating Local Solar Energy Generation Potential" explains how the City of San Jose used data from the U.S. Department of Energy's Cities Leading through Energy Analysis and Planning (Cities-LEAP) and the State and Local Energy Data (SLED) programs to inform its city energy planning. It is one of ten fact sheets in the "City Energy: From Data to Decisions" series.

Computed potential energy surfaces for chemical reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.

1994-01-01

Quantum mechanical methods have been used to compute potential energy surfaces for chemical reactions. The reactions studied were among those believed to be important to the NASP and HSR programs and included the recombination of two H atoms with several different third bodies; the reactions in the thermal Zeldovich mechanism; the reactions of H atom with O2, N2, and NO; reactions involved in the thermal De-NO(x) process; and the reaction of CH(squared Pi) with N2 (leading to 'prompt NO'). These potential energy surfaces have been used to compute reaction rate constants and rates of unimolecular decomposition. An additional application was the calculation of transport properties of gases using a semiclassical approximation (and in the case of interactions involving hydrogen inclusion of quantum mechanical effects).

Potential energy surfaces of Polonium isotopes

NASA Astrophysics Data System (ADS)

Nerlo-Pomorska, B.; Pomorski, K.; Schmitt, C.; Bartel, J.

2015-11-01

The evolution of the potential energy landscape is analysed in detail for ten even-even polonium isotopes in the mass range 188\\lt A\\lt 220 as obtained within the macroscopic-microscopic approach, relying on the Lublin-Strasbourg drop model and the Yukawa-folded single-particle energies for calculating the microscopic shell and pairing corrections. A variant of the modified Funny-Hills nuclear shape parametrization is used to efficiently map possible fission paths. The approach explains the main features of the fragment partition as measured in low-energy fission along the polonium chain. The latter lies in a transitional region of the nuclear chart, and will be essential to consistently understand the evolution of fission properties from neutron-deficient mercury to heavy actinides. The ability of our method to predict fission observables over such an extended region looks promising.

Assessment of potential biomass energy production in China towards 2030 and 2050

NASA Astrophysics Data System (ADS)

Zhao, Guangling

2018-01-01

The objective of this paper is to provide a more detailed picture of potential biomass energy production in the Chinese energy system towards 2030 and 2050. Biomass for bioenergy feedstocks comes from five sources, which are agricultural crop residues, forest residues and industrial wood waste, energy crops and woody crops, animal manure, and municipal solid waste. The potential biomass production is predicted based on the resource availability. In the process of identifying biomass resources production, assumptions are made regarding arable land, marginal land, crops yields, forest growth rate, and meat consumption and waste production. Four scenarios were designed to describe the potential biomass energy production to elaborate the role of biomass energy in the Chinese energy system in 2030. The assessment shows that under certain restrictions on land availability, the maximum potential biomass energy productions are estimated to be 18,833 and 24,901 PJ in 2030 and 2050.

The Department of Defense energy vulnerabilities: Potential problems and observations

NASA Astrophysics Data System (ADS)

Freiwald, D. A.; Berger, M. E.; Roach, J. F.

1982-08-01

The Department of Defense is almost entirely dependent on civilian energy supplies to meet its needs in both peacetime and periods of heightened conflict. There are a number of potential vulnerabilities to the continual and timely supply of energy to both the civilian and military sectors. These include denial of the energy resources themselves, disruption of critical transportation networks, destruction of storage facilities, and interruption of electrical power. This report briefly reviews the present situation for provision of energy from the civilian sector to the military. General vulnerabilities of the existing energy supply system are identified, along with the potential for armed aggression (including terrorist and sabotage activities) against the energy network. Conclusions and some tentative observations are made as to a proper response to the existing vulnerabilities.

New parameter-free polarization potentials in low-energy positron collisions

NASA Technical Reports Server (NTRS)

Jain, Ashok

1990-01-01

The polarization potential plays a decisive role in shaping up the cross sections in low energy positron collisions with atoms and molecules. However, its inclusion without involving any adjustable parameter, is still a challenge. Various other techniques employed so far for positron collisions are summarized, and a new, nonadjustable and very simple form of the polarization potential for positron-atom (molecule) collisions below the threshold of positronium formation is discussed. This new recently proposed potential is based on the correlation energy of a single positron in a homogeneous electron gas. The correlation energy was calculated by solving the Schrodinger equation of the positron-electron system and fitted to an analytical form in various ranges of the density parameter. In the outside region, the correlation energy is joined smoothly with the correct asymptotic form. This new positron correlation polarization (PCOP) potential was tested on several atomic and molecular targets such as the Ar, CO, and CH4. The results on the total and differential cross sections on these targets are shown along with the experimental data where available.

Saturation wind power potential and its implications for wind energy.

PubMed

Jacobson, Mark Z; Archer, Cristina L

2012-09-25

Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy.

Minimizing water consumption when producing hydropower

NASA Astrophysics Data System (ADS)

Leon, A. S.

2015-12-01

In 2007, hydropower accounted for only 16% of the world electricity production, with other renewable sources totaling 3%. Thus, it is not surprising that when alternatives are evaluated for new energy developments, there is strong impulse for fossil fuel or nuclear energy as opposed to renewable sources. However, as hydropower schemes are often part of a multipurpose water resources development project, they can often help to finance other components of the project. In addition, hydropower systems and their associated dams and reservoirs provide human well-being benefits, such as flood control and irrigation, and societal benefits such as increased recreational activities and improved navigation. Furthermore, hydropower due to its associated reservoir storage, can provide flexibility and reliability for energy production in integrated energy systems. The storage capability of hydropower systems act as a regulating mechanism by which other intermittent and variable renewable energy sources (wind, wave, solar) can play a larger role in providing electricity of commercial quality. Minimizing water consumption for producing hydropower is critical given that overuse of water for energy production may result in a shortage of water for other purposes such as irrigation, navigation or fish passage. This paper presents a dimensional analysis for finding optimal flow discharge and optimal penstock diameter when designing impulse and reaction water turbines for hydropower systems. The objective of this analysis is to provide general insights for minimizing water consumption when producing hydropower. This analysis is based on the geometric and hydraulic characteristics of the penstock, the total hydraulic head and the desired power production. As part of this analysis, various dimensionless relationships between power production, flow discharge and head losses were derived. These relationships were used to withdraw general insights on determining optimal flow discharge and

Minimally refined biomass fuel

DOEpatents

Pearson, Richard K.; Hirschfeld, Tomas B.

1984-01-01

A minimally refined fluid composition, suitable as a fuel mixture and derived from biomass material, is comprised of one or more water-soluble carbohydrates such as sucrose, one or more alcohols having less than four carbons, and water. The carbohydrate provides the fuel source; water solubilizes the carbohydrates; and the alcohol aids in the combustion of the carbohydrate and reduces the vicosity of the carbohydrate/water solution. Because less energy is required to obtain the carbohydrate from the raw biomass than alcohol, an overall energy savings is realized compared to fuels employing alcohol as the primary fuel.

Minimally nonlocal nucleon-nucleon potentials with chiral two-pion exchange including Δ resonances

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

Piarulli, M.; Girlanda, L.; Schiavilla, R.

In this study, we construct a coordinate-space chiral potential, including Δ-isobar intermediate states in its two-pion-exchange component up to order Q 3 (Q denotes generically the low momentum scale). The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders (Q 2 and Q 4, respectively) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constant multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 pp and 2982 np data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0–300 MeV. For themore » total 5291 $pp$ and $np$ data in this range, we obtain a Χ 2 /datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, R L and R S respectively, ranging from (R L,R S)=(1.2,0.8) fm down to (0.8,0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

Minimally nonlocal nucleon-nucleon potentials with chiral two-pion exchange including Δ resonances

DOE PAGES

Piarulli, M.; Girlanda, L.; Schiavilla, R.; ...

2015-02-26

In this study, we construct a coordinate-space chiral potential, including Δ-isobar intermediate states in its two-pion-exchange component up to order Q 3 (Q denotes generically the low momentum scale). The contact interactions entering at next-to-leading and next-to-next-to-next-to-leading orders (Q 2 and Q 4, respectively) are rearranged by Fierz transformations to yield terms at most quadratic in the relative momentum operator of the two nucleons. The low-energy constant multiplying these contact interactions are fitted to the 2013 Granada database, consisting of 2309 pp and 2982 np data (including, respectively, 148 and 218 normalizations) in the laboratory-energy range 0–300 MeV. For themore » total 5291 $pp$ and $np$ data in this range, we obtain a Χ 2 /datum of roughly 1.3 for a set of three models characterized by long- and short-range cutoffs, R L and R S respectively, ranging from (R L,R S)=(1.2,0.8) fm down to (0.8,0.6) fm. The long-range (short-range) cutoff regularizes the one- and two-pion exchange (contact) part of the potential.« less

NVU dynamics. I. Geodesic motion on the constant-potential-energy hypersurface.

PubMed

Ingebrigtsen, Trond S; Toxvaerd, Søren; Heilmann, Ole J; Schrøder, Thomas B; Dyre, Jeppe C

2011-09-14

An algorithm is derived for computer simulation of geodesics on the constant-potential-energy hypersurface of a system of N classical particles. First, a basic time-reversible geodesic algorithm is derived by discretizing the geodesic stationarity condition and implementing the constant-potential-energy constraint via standard Lagrangian multipliers. The basic NVU algorithm is tested by single-precision computer simulations of the Lennard-Jones liquid. Excellent numerical stability is obtained if the force cutoff is smoothed and the two initial configurations have identical potential energy within machine precision. Nevertheless, just as for NVE algorithms, stabilizers are needed for very long runs in order to compensate for the accumulation of numerical errors that eventually lead to "entropic drift" of the potential energy towards higher values. A modification of the basic NVU algorithm is introduced that ensures potential-energy and step-length conservation; center-of-mass drift is also eliminated. Analytical arguments confirmed by simulations demonstrate that the modified NVU algorithm is absolutely stable. Finally, we present simulations showing that the NVU algorithm and the standard leap-frog NVE algorithm have identical radial distribution functions for the Lennard-Jones liquid. © 2011 American Institute of Physics

Massively parallel GPU-accelerated minimization of classical density functional theory

NASA Astrophysics Data System (ADS)

Stopper, Daniel; Roth, Roland

2017-08-01

In this paper, we discuss the ability to numerically minimize the grand potential of hard disks in two-dimensional and of hard spheres in three-dimensional space within the framework of classical density functional and fundamental measure theory on modern graphics cards. Our main finding is that a massively parallel minimization leads to an enormous performance gain in comparison to standard sequential minimization schemes. Furthermore, the results indicate that in complex multi-dimensional situations, a heavy parallel minimization of the grand potential seems to be mandatory in order to reach a reasonable balance between accuracy and computational cost.

Design integration for minimal energy and cost

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

Halldane, J.E.

The authors present requirements for creating alternative energy conserving designs including energy management and architectural, plumbing, mechanical, electrical, electronic and optical design. Parameters of power, energy, life cycle costs and benefit for resource for an evaluation by the interested parties are discussed. They present an analysis of power systems through a seasonal power distribution diagram. An analysis of cost systems includes capital cost from the power components, annual costs from the utility energy use, and finance costs with loans, taxes, settlement and design fees. Equations are transposed to the evaluative parameter and are uniquely explicit with consistent symbols, parameter definitions,more » dual and balanced units, unit conversions, criteria for operation, incorporated constants for rapid calculations, references to data in the handbook, other common terms, and instrumentation for the measurement. Each component equation has a key power diagram.« less

Global Potential of Energy Efficiency Standards and Labeling Programs

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

McNeil, Michael A; McNeil, Michael A.; Letschert, Virginie

2008-06-15

This report estimates the global potential reductions in greenhouse gas emissions by 2030 for energy efficiency improvements associated with equipment (appliances, lighting, and HVAC) in buildings by means of energy efficiency standards and labels (EES&L). A consensus has emerged among the world's scientists and many corporate and political leaders regarding the need to address the threat of climate change through emissions mitigation and adaptation. A further consensus has emerged that a central component of these strategies must be focused around energy, which is the primary generator of greenhouse gas emissions. Two important questions result from this consensus: 'what kinds ofmore » policies encourage the appropriate transformation to energy efficiency' and 'how much impact can these policies have'? This report aims to contribute to the dialogue surrounding these issues by considering the potential impacts of a single policy type, applied on a global scale. The policy addressed in this report is Energy Efficient Standards and Labeling (EES&L) for energy-consuming equipment, which has now been implemented in over 60 countries. Mandatory energy performance standards are important because they contribute positively to a nation's economy and provide relative certainty about the outcome (both timing and magnitudes). Labels also contribute positively to a nation's economy and importantly increase the awareness of the energy-consuming public. Other policies not analyzed here (utility incentives, tax credits) are complimentary to standards and labels and also contribute in significant ways to reducing greenhouse gas emissions. We believe the analysis reported here to be the first systematic attempt to evaluate the potential of savings from EES&L for all countries and for such a large set of products. The goal of the analysis is to provide an assessment that is sufficiently well-quantified and accurate to allow comparison and integration with other strategies under

Saturation wind power potential and its implications for wind energy

PubMed Central

Jacobson, Mark Z.; Archer, Cristina L.

2012-01-01

Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world’s all-purpose power from wind in a 2030 clean-energy economy. PMID:23019353

On the potential energy in a gravitationally bound two-body system

NASA Astrophysics Data System (ADS)

Wilhelm, Klaus; Dwivedi, Bhola N.

2015-01-01

The potential energy problem in a gravitationally bound two-body system is studied in the framework of a recently proposed impact model of gravity (Wilhelm et al., 2013). The concept of a closed system has been modified, before the physical processes resulting in the liberation of the potential energy can be described. The energy is extracted from the background flux of hypothetical interaction entities.

Computed potential energy surfaces for chemical reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.

1990-01-01

The objective was to obtain accurate potential energy surfaces (PES's) for a number of reactions which are important in the H/N/O combustion process. The interest in this is centered around the design of the SCRAM jet engine for the National Aerospace Plane (NASP), which was envisioned as an air-breathing hydrogen-burning vehicle capable of reaching velocities as large as Mach 25. Preliminary studies indicated that the supersonic flow in the combustor region of the scram jet engine required accurate reaction rate data for reactions in the H/N/O system, some of which was not readily available from experiment. The most important class of combustion reactions from the standpoint of the NASP project are radical recombinaton reactions, since these reactions result in most of the heat release in the combustion process. Theoretical characterizations of the potential energy surfaces for these reactions are presented and discussed.

Repulsive nature of optical potentials for high-energy heavy-ion scattering

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

Furumoto, T.; Sakuragi, Y.; Yamamoto, Y.

2010-10-15

The recent works by the present authors predicted that the real part of heavy-ion optical potentials changes its character from attraction to repulsion around the incident energy per nucleon E/A=200-300 MeV on the basis of the complex G-matrix interaction and the double-folding model (DFM) and revealed that the three-body force plays an important role there. In the present paper, we have precisely analyzed the energy dependence of the calculated DFM potentials and its relation to the elastic-scattering angular distributions in detail in the case of the {sup 12}C+{sup 12}C system in the energy range of E/A=100-400 MeV. The tensor forcemore » contributes substantially to the energy dependence of the real part of the DFM potentials and plays an important role to lower the attractive-to-repulsive transition energy. The nearside and farside (N/F) decompositions of the elastic-scattering amplitudes clarify the close relation between the attractive-to-repulsive transition of the potentials and the characteristic evolution of the calculated angular distributions with the increase of the incident energy. Based on the present analysis, we propose experimental measurements for the predicted strong diffraction phenomena of the elastic-scattering angular distribution caused by the N/F interference around the attractive-to-repulsive transition energy together with the reduced diffractions below and above the transition energy.« less

Tachyon field non-minimally coupled to massive neutrino matter

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

Ahmad, Safia; Myrzakulov, Nurgissa; Myrzakulov, R., E-mail: safia@ctp-jamia.res.in, E-mail: nmyrzakulov@gmail.com, E-mail: rmyrzakulov@gmail.com

2016-07-01

In this paper, we consider rolling tachyon, with steep run-away type of potentials non-minimally coupled to massive neutrino matter. The coupling dynamically builds up at late times as neutrino matter turns non-relativistic. In case of scaling and string inspired potentials, we have shown that non-minimal coupling leads to minimum in the field potential. Given a suitable choice of model parameters, it is shown to give rise to late-time acceleration with the desired equation of state.

Energy-switching potential energy surface for the water molecule revisited: A highly accurate singled-sheeted form.

PubMed

Galvão, B R L; Rodrigues, S P J; Varandas, A J C

2008-07-28

A global ab initio potential energy surface is proposed for the water molecule by energy-switching/merging a highly accurate isotope-dependent local potential function reported by Polyansky et al. [Science 299, 539 (2003)] with a global form of the many-body expansion type suitably adapted to account explicitly for the dynamical correlation and parametrized from extensive accurate multireference configuration interaction energies extrapolated to the complete basis set limit. The new function mimics also the complicated Sigma/Pi crossing that arises at linear geometries of the water molecule.

Energy spectra and wave function of trigonometric Rosen-Morse potential as an effective quantum chromodynamics potential in D-dimensions

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

Deta, U. A., E-mail: utamaalan@yahoo.co.id; Suparmi,; Cari,

2014-09-30

The Energy Spectra and Wave Function of Schrodinger equation in D-Dimensions for trigonometric Rosen-Morse potential were investigated analytically using Nikiforov-Uvarov method. This potential captures the essential traits of the quark-gluon dynamics of Quantum Chromodynamics. The approximate energy spectra are given in the close form and the corresponding approximate wave function for arbitrary l-state (l ≠ 0) in D-dimensions are formulated in the form of differential polynomials. The wave function of this potential unnormalizable for general case. The wave function of this potential unnormalizable for general case. The existence of extra dimensions (centrifugal factor) and this potential increase the energy spectramore » of system.« less

Energy Efficiency Potential in the U.S. Single-Family Housing Stock

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

Wilson, Eric J.; Christensen, Craig B.; Horowitz, Scott G.

Typical approaches for assessing energy efficiency potential in buildings use a limited number of prototypes, and therefore suffer from inadequate resolution when pass-fail cost-effectiveness tests are applied, which can significantly underestimate or overestimate the economic potential of energy efficiency technologies. This analysis applies a new approach to large-scale residential energy analysis, combining the use of large public and private data sources, statistical sampling, detailed building simulations, and high-performance computing to achieve unprecedented granularity - and therefore accuracy - in modeling the diversity of the single-family housing stock. The result is a comprehensive set of maps, tables, and figures showing themore » technical and economic potential of 50 plus residential energy efficiency upgrades and packages for each state. Policymakers, program designers, and manufacturers can use these results to identify upgrades with the highest potential for cost-effective savings in a particular state or region, as well as help identify customer segments for targeted marketing and deployment. The primary finding of this analysis is that there is significant technical and economic potential to save electricity and on-site fuel use in the single-family housing stock. However, the economic potential is very sensitive to the cost-effectiveness criteria used for analysis. Additionally, the savings of particular energy efficiency upgrades is situation-specific within the housing stock (depending on climate, building vintage, heating fuel type, building physical characteristics, etc.).« less

Cloud-generated radiative heating and its generation of available potential energy

NASA Technical Reports Server (NTRS)

Stuhlmann, R.; Smith, G. L.

1989-01-01

The generation of zonal available potential energy (APE) by cloud radiative heating is discussed. The APE concept was mathematically formulated by Lorenz (1955) as a measure of the maximum amount of total potential energy that is available for conversion by adiabatic processes to kinetic energy. The rate of change of APE is the rate of the generation of APE minus the rate of conversion between potential and kinetic energy. By radiative transfer calculations, a mean cloud-generated radiative heating for a well defined set of cloud classes is derived as a function of cloud optical thickness. The formulation is suitable for using a general cloud parameter data set and has the advantage of taking into account nonlinearities between the microphysical and macrophysical cloud properties and the related radiation field.

Electromagnetic potentials basis for energy density and power flux

NASA Astrophysics Data System (ADS)

Puthoff, H. E.

2016-09-01

In rounding out the education of students in advanced courses in applied electromagnetics it is incumbent on us as mentors to raise issues that encourage appreciation of certain subtle aspects that are often overlooked during first exposure to the field. One of these has to do with the interplay between fields and potentials, with the latter often seen as just a convenient mathematical artifice useful in solving Maxwell’s equations. Nonetheless, to those practiced in application it is well understood that various alternatives in the use of fields and potentials are available within electromagnetic (EM) theory for the definitions of energy density, momentum transfer, EM stress-energy tensor, and so forth. Although the various options are all compatible with the basic equations of electrodynamics (e.g., Maxwell’s equations, Lorentz force law, gauge invariance), nonetheless certain alternative formulations lend themselves to being seen as preferable to others with regard to the transparency of their application to physical problems of interest. Here we argue for the transparency of an energy density/power flux option based on the EM potentials alone.

Simulation of minimally invasive vascular interventions for training purposes.

PubMed

Alderliesten, Tanja; Konings, Maurits K; Niessen, Wiro J

2004-01-01

To master the skills required to perform minimally invasive vascular interventions, proper training is essential. A computer simulation environment has been developed to provide such training. The simulation is based on an algorithm specifically developed to simulate the motion of a guide wire--the main instrument used during these interventions--in the human vasculature. In this paper, the design and model of the computer simulation environment is described and first results obtained with phantom and patient data are presented. To simulate minimally invasive vascular interventions, a discrete representation of a guide wire is used which allows modeling of guide wires with different physical properties. An algorithm for simulating the propagation of a guide wire within a vascular system, on the basis of the principle of minimization of energy, has been developed. Both longitudinal translation and rotation are incorporated as possibilities for manipulating the guide wire. The simulation is based on quasi-static mechanics. Two types of energy are introduced: internal energy related to the bending of the guide wire, and external energy resulting from the elastic deformation of the vessel wall. A series of experiments were performed on phantom and patient data. Simulation results are qualitatively compared with 3D rotational angiography data. The results indicate plausible behavior of the simulation.

Modelling the dynamics of a minimal protocell container

NASA Astrophysics Data System (ADS)

Nilsson Jacobi, Martin; Rasmussen, Steen; Tunstrøm, Kolbjørn

2005-01-01

This paper is a discussion on how reaction kinetics and three-dimensional (3D) lattice simulations can be used to elucidate the dynamical properties of micelles as a possible minimal protocell container. We start with a general discussion on the role of molecular self-assembly in prebiotic and contemporary biological systems. A simple reaction kinetic model of a micellation process of amphiphilic molecules in water is then presented and solved analytically. Amphiphilic molecules are polymers with hydrophobic (water-fearing), e.g. hydrocarbon tail groups, and hydrophilic (water-loving) head groups, e.g. fatty acids. By making a few simplifying assumptions an analytical expression for the size distribution of the resulting micelles can be derived. The main part of the paper presents and discusses a lattice gas technique for a more detailed 3D simulation of molecular self-assembly of amphiphilic polymers in aqueous environments. Water molecules, hydrocarbon tail groups and hydrophilic head groups are explicitly represented on a three-dimensional discrete lattice. Molecules move on the lattice proportional to their continuous momentum. Collision rules preserve momentum and kinetic energy. Potential energy from molecular interactions are also included explicitly. The non-trivial thermodynamics of large-scale and long-time dynamics are studied. In this paper we specifically demonstrate how, from a random initial distribution, micelles are formed and grow until they destabilize and can divide. Eventually a steady state of growing and dividing micelles is formed. Towards the end of the paper we discuss the relevance of the presented results to the design of a minimal artificial protocell.

Economic impact of minimally invasive lumbar surgery.

PubMed

Hofstetter, Christoph P; Hofer, Anna S; Wang, Michael Y

2015-03-18

Cost effectiveness has been demonstrated for traditional lumbar discectomy, lumbar laminectomy as well as for instrumented and noninstrumented arthrodesis. While emerging evidence suggests that minimally invasive spine surgery reduces morbidity, duration of hospitalization, and accelerates return to activites of daily living, data regarding cost effectiveness of these novel techniques is limited. The current study analyzes all available data on minimally invasive techniques for lumbar discectomy, decompression, short-segment fusion and deformity surgery. In general, minimally invasive spine procedures appear to hold promise in quicker patient recovery times and earlier return to work. Thus, minimally invasive lumbar spine surgery appears to have the potential to be a cost-effective intervention. Moreover, novel less invasive procedures are less destabilizing and may therefore be utilized in certain indications that traditionally required arthrodesis procedures. However, there is a lack of studies analyzing the economic impact of minimally invasive spine surgery. Future studies are necessary to confirm the durability and further define indications for minimally invasive lumbar spine procedures.

Classical Trajectory Study of Collision Energy Transfer between Ne and C2H2 on a Full Dimensional Accurate Potential Energy Surface.

PubMed

Liu, Yang; Huang, Yin; Ma, Jianyi; Li, Jun

2018-02-15

Collision energy transfer plays an important role in gas phase reaction kinetics and relaxation of excited molecules. However, empirical treatments are generally adopted for the collisional energy transfer in the master equation based approach. In this work, classical trajectory approach is employed to investigate the collision energy transfer dynamics in the C 2 H 2 -Ne system. The entire potential energy surface is described as the sum of the C 2 H 2 potential and interaction potential between C 2 H 2 and Ne. It is highlighted that both parts of the entire potential are highly accurate. In particular, the interaction potential is fit to ∼41 300 configurations determined at the level of CCSD(T)-F12a/cc-pCVTZ-F12 with the counterpoise correction. Collision energy transfer dynamics are then carried out on this benchmark potential and the widely used Lennard-Jones and Buckingham interaction potentials. Energy transfers and related probability densities at different collisional energies are reported and discussed.

Residential energy efficiency: Progress since 1973 and future potential

NASA Astrophysics Data System (ADS)

Rosenfeld, Arthur H.

1985-11-01

Today's 85 million U.S. homes use 100 billion of fuel and electricity (1150/home). If their energy intensity (resource energy/ft2) were still frozen at 1973 levels, they would use 18% more. With well-insulated houses, need for space heat is vanishing. Superinsulated Saskatchewan homes spend annually only 270 for space heat, 150 for water heat, and 400 for appliances, yet they cost only 2000±1000 more than conventional new homes. The concept of Cost of Conserved Energy (CCE) is used to rank conservation technologies for existing and new homes and appliances, and to develop supply curves of conserved energy and a least cost scenario. Calculations are calibrated with the BECA and other data bases. By limiting investments in efficiency to those whose CCE is less than current fuel and electricity prices, the potential residential plus commercial energy use in 2000 AD drops to half of that estimated by DOE, and the number of power plants needed drops by 200. For the whole buildings sector, potential savings by 2000 are 8 Mbod (worth 50B/year), at an average CCE of 10/barrel.

Metallic bionanocatalysts: potential applications as green catalysts and energy materials.

PubMed

Macaskie, Lynne E; Mikheenko, Iryna P; Omajai, Jacob B; Stephen, Alan J; Wood, Joseph

2017-09-01

Microbially generated or supported nanocatalysts have potential applications in green chemistry and environmental application. However, precious (and base) metals biorefined from wastes may be useful for making cheap, low-grade catalysts for clean energy production. The concept of bionanomaterials for energy applications is reviewed with respect to potential fuel cell applications, bio-catalytic upgrading of oils and manufacturing 'drop-in fuel' precursors. Cheap, effective biomaterials would facilitate progress towards dual development goals of sustainable consumption and production patterns and help to ensure access to affordable, reliable, sustainable and modern energy. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Free energy landscape of protein-like chains with discontinuous potentials

NASA Astrophysics Data System (ADS)

Movahed, Hanif Bayat; van Zon, Ramses; Schofield, Jeremy

2012-06-01

In this article the configurational space of two simple protein models consisting of polymers composed of a periodic sequence of four different kinds of monomers is studied as a function of temperature. In the protein models, hydrogen bond interactions, electrostatic repulsion, and covalent bond vibrations are modeled by discontinuous step, shoulder, and square-well potentials, respectively. The protein-like chains exhibit a secondary alpha helix structure in their folded states at low temperatures, and allow a natural definition of a configuration by considering which beads are bonded. Free energies and entropies of configurations are computed using the parallel tempering method in combination with hybrid Monte Carlo sampling of the canonical ensemble of the discontinuous potential system. The probability of observing the most common configuration is used to analyze the nature of the free energy landscape, and it is found that the model with the least number of possible bonds exhibits a funnel-like free energy landscape at low enough temperature for chains with fewer than 30 beads. For longer proteins, the free landscape consists of several minima, where the configuration with the lowest free energy changes significantly by lowering the temperature and the probability of observing the most common configuration never approaches one due to the degeneracy of the lowest accessible potential energy.

Material and energy recovery in integrated waste management systems: the potential for energy recovery.

PubMed

Consonni, Stefano; Viganò, Federico

2011-01-01

This article is part of a set of six coordinated papers reporting the main findings of a research project carried out by five Italian universities on "Material and energy recovery in Integrated Waste Management Systems (IWMS)". An overview of the project and a summary of the most relevant results can be found in the introductory article of the series. This paper describes the work related to the evaluation of mass and energy balances, which has consisted of three major efforts (i) development of a model for quantifying the energy content and the elemental compositions of the waste streams appearing in a IWMS; (ii) upgrade of an earlier model to predict the performances of Waste-to-Energy (WtE) plants; (iii) evaluation of mass and energy balances of all the scenarios and the recovery paths considered in the project. Results show that not only the amount of material available for energy recovery is significantly higher than the Unsorted Residual Waste (URW) left after Separate Collection (SC), because selection and recycling generate significant amounts of residues, but its heating value is higher than that of the original, gross waste. Therefore, the energy potential of what is left after recycling is always higher than the complement to 100% of the Source Separation Level (SSL). Also, increasing SSL has marginal effects on the potential for energy recovery: nearly doubling SSL (from 35% to 65%) reduces the energy potential only by one fourth. Consequently, even at high SSL energy recovery is a fundamental step of a sustainable waste management system. Variations of SSL do bring about variations of the composition, heating value and moisture content of the material fed to WtE plants, but these variations (i) are smaller than one can expect; (ii) have marginal effects on the performances of the WtE plant. These considerations suggest that the mere value of SSL is not a good indicator of the quality of the waste management system, nor of its energy and environmental

Reconstructing free-energy landscapes for nonequilibrium periodic potentials

NASA Astrophysics Data System (ADS)

López-Alamilla, N. J.; Jack, Michael W.; Challis, K. J.

2018-03-01

We present a method for reconstructing the free-energy landscape of overdamped Brownian motion on a tilted periodic potential. Our approach exploits the periodicity of the system by using the k -space form of the Smoluchowski equation and we employ an iterative approach to determine the nonequilibrium tilt. We reconstruct landscapes for a number of example potentials to show the applicability of the method to both deep and shallow wells and near-to- and far-from-equilibrium regimes. The method converges logarithmically with the number of Fourier terms in the potential.

Review of Potential Characterization Techniques in Approaching Energy and Sustainability

DOE PAGES

LePoire, David

2014-03-20

Societal prosperity is linked to sustainable energy and a healthy environment. But, tough global challenges include increased demand for fossil fuels, while approaching peak oil production and uncertainty in the environmental impacts of energy generation. Recently, energy use was identified as a major component of economic productivity, along with capital and labor. Furthermore, other environmental resources and impacts may be nearing environmental thresholds as indicated by nine planetary environmental boundaries, many of which are linked to energy production and use. Foresight techniques could be applied to guide future actions which include emphasis on (1) energy efficiency to bridge the transitionmore » to a renewable energy economy, (2) continued research, development, and assessment of new technologies, (3) improved understanding of environment impacts including natural capital use and degradation, (4) exploration of GDP alternative measures that include both economic production and environmental impacts, and (5) international cooperation and awareness of longer-term opportunities and their associated potential scenarios. Examples from the U.S. and the international community illustrate challenges and potential.« less

Supergravity contributions to inflation in models with non-minimal coupling to gravity

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

Das, Kumar; Dutta, Koushik; Domcke, Valerie, E-mail: kumar.das@saha.ac.in, E-mail: valerie.domcke@apc.univ-paris7.fr, E-mail: koushik.dutta@saha.ac.in

2017-03-01

This paper provides a systematic study of supergravity contributions relevant for inflationary model building in Jordan frame supergravity. In this framework, canonical kinetic terms in the Jordan frame result in the separation of the Jordan frame scalar potential into a tree-level term and a supergravity contribution which is potentially dangerous for sustaining inflation. We show that if the vacuum energy necessary for driving inflation originates dominantly from the F-term of an auxiliary field (i.e. not the inflaton), the supergravity corrections to the Jordan frame scalar potential are generically suppressed. Moreover, these supergravity contributions identically vanish if the superpotential vanishes alongmore » the inflationary trajectory. On the other hand, if the F-term associated with the inflaton dominates the vacuum energy, the supergravity contributions are generically comparable to the globally supersymmetric contributions. In addition, the non-minimal coupling to gravity inherent to Jordan frame supergravity significantly impacts the inflationary model depending on the size and sign of this coupling. We discuss the phenomenology of some representative inflationary models, and point out the relation to the recently much discussed cosmological 'attractor' models.« less

Potential energy distribution function and its application to the problem of evaporation

NASA Astrophysics Data System (ADS)

Gerasimov, D. N.; Yurin, E. I.

2017-10-01

Distribution function on potential energy in a strong correlated system can be calculated analytically. In an equilibrium system (for instance, in the bulk of the liquid) this distribution function depends only on temperature and mean potential energy, which can be found through the specific heat of vaporization. At the surface of the liquid this distribution function differs significantly, but its shape still satisfies analytical correlation. Distribution function on potential energy nearby the evaporation surface can be used instead of the work function of the atom of the liquid.

Surface tension, surface energy, and chemical potential due to their difference.

PubMed

Hui, C-Y; Jagota, A

2013-09-10

It is well-known that surface tension and surface energy are distinct quantities for solids. Each can be regarded as a thermodynamic property related first by Shuttleworth. Mullins and others have suggested that the difference between surface tension and surface energy cannot be sustained and that the two will approach each other over time. In this work we show that in a single-component system where changes in elastic energy can be neglected, the chemical potential difference between the surface and bulk is proportional to the difference between surface tension and surface energy. By further assuming that mass transfer is driven by this chemical potential difference, we establish a model for the kinetics by which mass transfer removes the difference between surface tension and surface energy.

Perturbed Yukawa textures in the minimal seesaw model

NASA Astrophysics Data System (ADS)

Rink, Thomas; Schmitz, Kai

2017-03-01

We revisit the minimal seesaw model, i.e., the type-I seesaw mechanism involving only two right-handed neutrinos. This model represents an important minimal benchmark scenario for future experimental updates on neutrino oscillations. It features four real parameters that cannot be fixed by the current data: two CP -violating phases, δ and σ, as well as one complex parameter, z, that is experimentally inaccessible at low energies. The parameter z controls the structure of the neutrino Yukawa matrix at high energies, which is why it may be regarded as a label or index for all UV completions of the minimal seesaw model. The fact that z encompasses only two real degrees of freedom allows us to systematically scan the minimal seesaw model over all of its possible UV completions. In doing so, we address the following question: suppose δ and σ should be measured at particular values in the future — to what extent is one then still able to realize approximate textures in the neutrino Yukawa matrix? Our analysis, thus, generalizes previous studies of the minimal seesaw model based on the assumption of exact texture zeros. In particular, our study allows us to assess the theoretical uncertainty inherent to the common texture ansatz. One of our main results is that a normal light-neutrino mass hierarchy is, in fact, still consistent with a two-zero Yukawa texture, provided that the two texture zeros receive corrections at the level of O (10%). While our numerical results pertain to the minimal seesaw model only, our general procedure appears to be applicable to other neutrino mass models as well.

Potential Arbitrage Revenue of Energy Storage Systems in PJM

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

Salles, Mauricio; Huang, Junling; Aziz, Michael

The volatility of electricity prices is attracting interest in the opportunity of providing net revenue by energy arbitrage. We analyzed the potential revenue of a generic Energy Storage System (ESS) in 7395 different locations within the electricity markets of Pennsylvania-New Jersey-Maryland interconnection (PJM), the largest U.S. regional transmission organization, using hourly locational marginal prices over the seven-year period 2008–2014. Assuming a price-taking ESS with perfect foresight in the real-time market, we optimized the charge-discharge profile to determine the maximum potential revenue for a 1 MW system as a function of energy/power ratio, or rated discharge duration, from 1 to 14more » h, including a limited analysis of sensitivity to round-trip efficiency. We determined minimum potential revenue with a similar analysis of the day-ahead market. We presented the distribution over the set of nodes and years of price, price volatility, and maximum potential arbitrage revenue. From these results, we determined the break even overnight installed cost of an ESS below which arbitrage would be profitable, its dependence on rated discharge duration, its distribution over grid nodes, and its variation over the years. We showed that dispatch into real-time markets based on day-ahead market settlement prices is a simple, feasible method that raises the lower bound on the achievable arbitrage revenue.« less

Potential Arbitrage Revenue of Energy Storage Systems in PJM

DOE PAGES

Salles, Mauricio; Huang, Junling; Aziz, Michael; ...

2017-07-27

The volatility of electricity prices is attracting interest in the opportunity of providing net revenue by energy arbitrage. We analyzed the potential revenue of a generic Energy Storage System (ESS) in 7395 different locations within the electricity markets of Pennsylvania-New Jersey-Maryland interconnection (PJM), the largest U.S. regional transmission organization, using hourly locational marginal prices over the seven-year period 2008–2014. Assuming a price-taking ESS with perfect foresight in the real-time market, we optimized the charge-discharge profile to determine the maximum potential revenue for a 1 MW system as a function of energy/power ratio, or rated discharge duration, from 1 to 14more » h, including a limited analysis of sensitivity to round-trip efficiency. We determined minimum potential revenue with a similar analysis of the day-ahead market. We presented the distribution over the set of nodes and years of price, price volatility, and maximum potential arbitrage revenue. From these results, we determined the break even overnight installed cost of an ESS below which arbitrage would be profitable, its dependence on rated discharge duration, its distribution over grid nodes, and its variation over the years. We showed that dispatch into real-time markets based on day-ahead market settlement prices is a simple, feasible method that raises the lower bound on the achievable arbitrage revenue.« less

Intermolecular Potentials of Methane Assessed by Second Virial Coefficients, ab Initio Dimer Interaction Energies, and Aggregate Cohesive Energies.

PubMed

Ribeiro, Douglas S

2017-06-01

This study presents computations of three energy related properties for 26 previously published multisite intermolecular potentials of methane: MM2, MM3, MM2en, MM3en, MM2mc, MM3mc, MM3envir, RMK, OPLS all-atom, MUB-2, AMBER, BOYD, Williams, Sheikh, MG, Tsuzuki, E2-Gay, E4-Gay, MP4exp-6(iii), MP4exp-6(iv), Rowley-A, Rowley-B, TraPPE-EH, Ouyang, CLC, and Chao and three united atom potentials: Saager-Fischer (SF), OPLS united atom, and HFD. The three properties analyzed are the second virial coefficients for 14 temperature points in the range of 110 to 623.15 K, the interaction energies for 12 orientations of the methane dimer as a function of distance followed by a comparison to three ab initio data sets and the cohesive energy of the aggregate of 512 methane molecules. The latter computed energies are correlated to latent heat of evaporation of 11 potentials and are proposed as surrogate approximate parameters for ΔH vap for the studied potentials. The 10 best performing potentials are selected by rms order in each one of the properties and three of them are found to be present simultaneously in the three sets: Tsuzuki, MM3mc, and MM2mc. On the basis of the cohesive energy of the aggregate, a quantitative measure of the anisotropy of the potentials is proposed. The results are discussed on the basis of anisotropy, nonadditivity and ability of the potentials to reproduce ab initio data. It is concluded that the nonadditivity of the pair potentials holds and the available ab initio data did not lead to pair potentials that are cohesive enough to reproduce accurately the second virial coefficients.

An adaptive interpolation scheme for molecular potential energy surfaces

NASA Astrophysics Data System (ADS)

Kowalewski, Markus; Larsson, Elisabeth; Heryudono, Alfa

2016-08-01

The calculation of potential energy surfaces for quantum dynamics can be a time consuming task—especially when a high level of theory for the electronic structure calculation is required. We propose an adaptive interpolation algorithm based on polyharmonic splines combined with a partition of unity approach. The adaptive node refinement allows to greatly reduce the number of sample points by employing a local error estimate. The algorithm and its scaling behavior are evaluated for a model function in 2, 3, and 4 dimensions. The developed algorithm allows for a more rapid and reliable interpolation of a potential energy surface within a given accuracy compared to the non-adaptive version.

Potential for the Use of Energy Savings Performance Contracts to Reduce Energy Consumption and Provide Energy and Cost Savings in Non-Building Applications

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

Williams, Charles; Green, Andrew S.; Dahle, Douglas

2013-08-01

The findings of this study indicate that potential exists in non-building applications to save energy and costs. This potential could save billions of federal dollars, reduce reliance on fossil fuels, increase energy independence and security, and reduce greenhouse gas emissions. The Federal Government has nearly twenty years of experience with achieving similar energy cost reductions, and letting the energy costs savings pay for themselves, by applying energy savings performance contracts (ESPC) inits buildings. Currently, the application of ESPCs is limited by statute to federal buildings. This study indicates that ESPCs can be a compatible and effective contracting tool for achievingmore » savings in non-building applications.« less

Radioistopes to Solar to High Energy Accelerators - Chip-Scale Energy Sources

NASA Astrophysics Data System (ADS)

Lal, Amit

2013-12-01

This talk will present MEMS based power sources that utilize radioisotopes, solar energy, and potentially nuclear energy through advancements in integration of new structures and materials within MEMS. Micro power harvesters can harness power from vibration, radioisotopes, light, sound, and biology may provide pathways to minimize or even eliminate batteries in sensor nodes. In this talk work on radioisotope thin films for MEMS will be include the self-reciprocating cantilever, betavoltaic cells, and high DC voltages. The self-reciprocating cantilever energy harvester allows small commercially viable amounts of radioisotopes to generate mW to Watts of power so that very reliable power sources that last 100s of years are possible. The tradeoffs between reliability and potential stigma with radioisotopes allow one to span a useful design space with reliability as a key parameter. These power sources provide pulsed power at three different time scales using mechanical, RF, and static extraction of energy from collected charge. Multi-use capability, both harvesting radioisotope power and local vibration energy extends the reliability of micro-power sources further.

The B 1Πu potential energy curve and dissociation energy of 39K2

NASA Astrophysics Data System (ADS)

Heinze, Johannes; Engelke, Friedrich

1988-07-01

The 39K2 B 1Πu potential energy curve has been determined using laser spectroscopic techniques and quantum mechanical calculations. The dissociation energy is 2407.6±0.5 cm-1 (0.2985±0.0001 eV) including a potential barrier of 298±10 cm-1 (0.037±0.0013 eV) found with its maximum at 8.08±0.05 Å (15.3±0.1 bohr). The long-range behavior matches smoothly onto the form predicted from dispersion forces. The dissociation energy of the ground state X 1Σ+g, obtained by a long-range extrapolation of the vibrational separations, is De =4444±10 cm-1 (0.5506±0.0013 eV), in agreement with recent theoretical prediction.

Major Energy Plants and Their Potential for Bioenergy Development in China

NASA Astrophysics Data System (ADS)

Li, Xiaofeng; Hou, Shenglin; Su, Man; Yang, Mingfeng; Shen, Shihua; Jiang, Gaoming; Qi, Dongmei; Chen, Shuangyan; Liu, Gongshe

2010-10-01

China is rich in energy plant resources. In this article, 64 plant species are identified as potential energy plants in China. The energy plant species include 38 oilseed crops, 5 starch-producing crops, 3 sugar-producing crops and 18 species for lignocellulosic biomass. The species were evaluated on the basis of their production capacity and their resistance to salt, drought, and/or low temperature stress. Ten plant species have high production and/or stress resistance and can be potentially developed as the candidate energy plants. Of these, four species could be the primary energy plants in China: Barbados nut ( Jatropha curcas L.), Jerusalem artichoke ( Helianthus tuberosus L.), sweet sorghum ( Sorghum bicolor L.) and Chinese silvergrass ( Miscanthus sinensis Anderss.). We discuss the use of biotechnological techniques such as genome sequencing, molecular markers, and genetic transformation to improve energy plants. These techniques are being used to develop new cultivars and to analyze and manipulate genetic variation to improve attributes of energy plants in China.

Conformational Sampling of a Biomolecular Rugged Energy Landscape.

PubMed

Rydzewski, Jakub; Jakubowski, Rafal; Nicosia, Giuseppe; Nowak, Wieslaw

2018-01-01

The protein structure refinement using conformational sampling is important in hitherto protein studies. In this paper, we examined the protein structure refinement by means of potential energy minimization using immune computing as a method of sampling conformations. The method was tested on the x-ray structure and 30 decoys of the mutant of [Leu]Enkephalin, a paradigmatic example of the biomolecular multiple-minima problem. In order to score the refined conformations, we used a standard potential energy function with the OPLSAA force field. The effectiveness of the search was assessed using a variety of methods. The robustness of sampling was checked by the energy yield function which measures quantitatively the number of the peptide decoys residing in an energetic funnel. Furthermore, the potential energy-dependent Pareto fronts were calculated to elucidate dissimilarities between peptide conformations and the native state as observed by x-ray crystallography. Our results showed that the probed potential energy landscape of [Leu]Enkephalin is self-similar on different metric scales and that the local potential energy minima of the peptide decoys are metastable, thus they can be refined to conformations whose potential energy is decreased by approximately 250 kJ/mol.

Minimally Invasive Surgery (MIS) Approaches to Thoracolumbar Trauma.

PubMed

Kaye, Ian David; Passias, Peter

2018-03-01

Minimally invasive surgical (MIS) techniques offer promising improvements in the management of thoracolumbar trauma. Recent advances in MIS techniques and instrumentation for degenerative conditions have heralded a growing interest in employing these techniques for thoracolumbar trauma. Specifically, surgeons have applied these techniques to help manage flexion- and extension-distraction injuries, neurologically intact burst fractures, and cases of damage control. Minimally invasive surgical techniques offer a means to decrease blood loss, shorten operative time, reduce infection risk, and shorten hospital stays. Herein, we review thoracolumbar minimally invasive surgery with an emphasis on thoracolumbar trauma classification, minimally invasive spinal stabilization, surgical indications, patient outcomes, technical considerations, and potential complications.

On the Minimal Length Uncertainty Relation and the Foundations of String Theory

DOE PAGES

Chang, Lay Nam; Lewis, Zachary; Minic, Djordje; ...

2011-01-01

We review our work on the minimal length uncertainty relation as suggested by perturbative string theory. We discuss simple phenomenological implications of the minimal length uncertainty relation and then argue that the combination of the principles of quantum theory and general relativity allow for a dynamical energy-momentum space. We discuss the implication of this for the problem of vacuum energy and the foundations of nonperturbative string theory.

Influence of combined fundamental potentials in a nonlinear vibration energy harvester

NASA Astrophysics Data System (ADS)

Podder, Pranay; Mallick, Dhiman; Amann, Andreas; Roy, Saibal

2016-11-01

Ambient mechanical vibrations have emerged as a viable energy source for low-power wireless sensor nodes aiming the upcoming era of the ‘Internet of Things’. Recently, purposefully induced dynamical nonlinearities have been exploited to widen the frequency spectrum of vibration energy harvesters. Here we investigate some critical inconsistencies between the theoretical formulation and applications of the bistable Duffing nonlinearity in vibration energy harvesting. A novel nonlinear vibration energy harvesting device with the capability to switch amidst individually tunable bistable-quadratic, monostable-quartic and bistable-quartic potentials has been designed and characterized. Our study highlights the fundamentally different large deflection behaviors of the theoretical bistable-quartic Duffing oscillator and the experimentally adapted bistable-quadratic systems, and underlines their implications in the respective spectral responses. The results suggest enhanced performance in the bistable-quartic potential in comparison to others, primarily due to lower potential barrier and higher restoring forces facilitating large amplitude inter-well motion at relatively lower accelerations.

Stalking Higher Energy Conformers on the Potential Energy Surface of Charged Species.

PubMed

Brites, Vincent; Cimas, Alvaro; Spezia, Riccardo; Sieffert, Nicolas; Lisy, James M; Gaigeot, Marie-Pierre

2015-03-10

Combined theoretical DFT-MD and RRKM methodologies and experimental spectroscopic infrared predissociation (IRPD) strategies to map potential energy surfaces (PES) of complex ionic clusters are presented, providing lowest and high energy conformers, thresholds to isomerization, and cluster formation pathways. We believe this association not only represents a significant advance in the field of mapping minima and transition states on the PES but also directly measures dynamical pathways for the formation of structural conformers and isomers. Pathways are unraveled over picosecond (DFT-MD) and microsecond (RRKM) time scales while changing the amount of internal energy is experimentally achieved by changing the loss channel for the IRPD measurements, thus directly probing different kinetic and isomerization pathways. Demonstration is provided for Li(+)(H2O)3,4 ionic clusters. Nonstatistical formation of these ionic clusters by both direct and cascade processes, involving isomerization processes that can lead to trapping of high energy conformers along the paths due to evaporative cooling, has been unraveled.

Bio-Energy Retains Its Mitigation Potential Under Elevated CO2

PubMed Central

Bellassen, Valentin; Njakou Djomo, Sylvestre; Lukac, Martin; Calfapietra, Carlo; Janssens, Ivan A.; Hoosbeek, Marcel R.; Viovy, Nicolas; Churkina, Galina; Scarascia-Mugnozza, Giuseppe; Ceulemans, Reinhart

2010-01-01

Background If biofuels are to be a viable substitute for fossil fuels, it is essential that they retain their potential to mitigate climate change under future atmospheric conditions. Elevated atmospheric CO2 concentration [CO2] stimulates plant biomass production; however, the beneficial effects of increased production may be offset by higher energy costs in crop management. Methodology/Main Findings We maintained full size poplar short rotation coppice (SRC) systems under both current ambient and future elevated [CO2] (550 ppm) and estimated their net energy and greenhouse gas balance. We show that a poplar SRC system is energy efficient and produces more energy than required for coppice management. Even more, elevated [CO2] will increase the net energy production and greenhouse gas balance of a SRC system with 18%. Managing the trees in shorter rotation cycles (i.e., 2 year cycles instead of 3 year cycles) will further enhance the benefits from elevated [CO2] on both the net energy and greenhouse gas balance. Conclusions/Significance Adapting coppice management to the future atmospheric [CO2] is necessary to fully benefit from the climate mitigation potential of bio-energy systems. Further, a future increase in potential biomass production due to elevated [CO2] outweighs the increased production costs resulting in a northward extension of the area where SRC is greenhouse gas neutral. Currently, the main part of the European terrestrial carbon sink is found in forest biomass and attributed to harvesting less than the annual growth in wood. Because SRC is intensively managed, with a higher turnover in wood production than conventional forest, northward expansion of SRC is likely to erode the European terrestrial carbon sink. PMID:20657833

Relationship of the Williams-Poulios and Manning-Rosen Potential Energy Models for Diatomic Molecules

NASA Astrophysics Data System (ADS)

Jia, Chun-Sheng; Liang, Guang-Chuan; Peng, Xiao-Long; Tang, Hong-Ming; Zhang, Lie-Hui

2014-06-01

By employing the dissociation energy and the equilibrium bond length for a diatomic molecule as explicit parameters, we generate an improved form of the Williams-Poulios potential energy model. It is found that the negative Williams-Poulios potential model is equivalent to the Manning-Rosen potential model for diatomic molecules. We observe that the Manning-Rosen potential is superior to the Morse potential in reproducing the interaction potential energy curves for the {{a}3 Σu+} state of the 6Li2 molecule and the {{X}1 sum+} state of the SiF+ molecule.

Beam-energy-spread minimization using cell-timing optimization

NASA Astrophysics Data System (ADS)

Rose, C. R.; Ekdahl, C.; Schulze, M.

2012-04-01

Beam energy spread, and related beam motion, increase the difficulty in tuning for multipulse radiographic experiments at the dual-axis radiographic hydrodynamic test facility’s axis-II linear induction accelerator (LIA). In this article, we describe an optimization method to reduce the energy spread by adjusting the timing of the cell voltages (both unloaded and loaded), either advancing or retarding, such that the injector voltage and summed cell voltages in the LIA result in a flatter energy profile. We developed a nonlinear optimization routine which accepts as inputs the 74 cell-voltage, injector voltage, and beam current waveforms. It optimizes cell timing per user-selected groups of cells and outputs timing adjustments, one for each of the selected groups. To verify the theory, we acquired and present data for both unloaded and loaded cell-timing optimizations. For the unloaded cells, the preoptimization baseline energy spread was reduced by 34% and 31% for two shots as compared to baseline. For the loaded-cell case, the measured energy spread was reduced by 49% compared to baseline.

Minimizers with Bounded Action for the High-Dimensional Frenkel-Kontorova Model

NASA Astrophysics Data System (ADS)

Miao, Xue-Qing; Wang, Ya-Nan; Qin, Wen-Xin

In Aubry-Mather theory for monotone twist maps or for one-dimensional Frenkel-Kontorova (FK) model with nearest neighbor interactions, each global minimizer (minimal energy configuration) is naturally Birkhoff. However, this is not true for the one-dimensional FK model with non-nearest neighbor interactions or for the high-dimensional FK model. In this paper, we study the Birkhoff property of minimizers with bounded action for the high-dimensional FK model.

The global technical potential of bio-energy in 2050 considering sustainability constraints

PubMed Central

Haberl, Helmut; Beringer, Tim; Bhattacharya, Sribas C; Erb, Karl-Heinz; Hoogwijk, Monique

2010-01-01

Bio-energy, that is, energy produced from organic non-fossil material of biological origin, is promoted as a substitute for non-renewable (e.g., fossil) energy to reduce greenhouse gas (GHG) emissions and dependency on energy imports. At present, global bio-energy use amounts to approximately 50 EJ/yr, about 10% of humanity's primary energy supply. We here review recent literature on the amount of bio-energy that could be supplied globally in 2050, given current expectations on technology, food demand and environmental targets (‘technical potential’). Recent studies span a large range of global bio-energy potentials from ≈30 to over 1000 EJ/yr. In our opinion, the high end of the range is implausible because of (1) overestimation of the area available for bio-energy crops due to insufficient consideration of constraints (e.g., area for food, feed or nature conservation) and (2) too high yield expectations resulting from extrapolation of plot-based studies to large, less productive areas. According to this review, the global technical primary bio-energy potential in 2050 is in the range of 160–270 EJ/yr if sustainability criteria are considered. The potential of bio-energy crops is at the lower end of previously published ranges, while residues from food production and forestry could provide significant amounts of energy based on an integrated optimization (‘cascade utilization’) of biomass flows. PMID:24069093

An adaptive interpolation scheme for molecular potential energy surfaces

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

Kowalewski, Markus, E-mail: mkowalew@uci.edu; Larsson, Elisabeth; Heryudono, Alfa

The calculation of potential energy surfaces for quantum dynamics can be a time consuming task—especially when a high level of theory for the electronic structure calculation is required. We propose an adaptive interpolation algorithm based on polyharmonic splines combined with a partition of unity approach. The adaptive node refinement allows to greatly reduce the number of sample points by employing a local error estimate. The algorithm and its scaling behavior are evaluated for a model function in 2, 3, and 4 dimensions. The developed algorithm allows for a more rapid and reliable interpolation of a potential energy surface within amore » given accuracy compared to the non-adaptive version.« less

Bifurcations on Potential Energy Surfaces of Organic Reactions

PubMed Central

Ess, Daniel H.; Wheeler, Steven E.; Iafe, Robert G.; Xu, Lai; Çelebi-Ölçüm, Nihan; Houk, K. N.

2009-01-01

A single transition state may lead to multiple intermediates or products if there is a post-transition state reaction path bifurcation. These bifurcations arise when there are sequential transition states with no intervening energy minimum. For such systems, the shape of the potential energy surface and dynamic effects control selectivity rather than transition state energetics. This minireview covers recent investigations of organic reactions exhibiting reaction pathway bifurcations. Such phenomena are surprisingly general and affect experimental observables such as kinetic isotope effects and product distributions. PMID:18767086

Solar Pond Potential as A New Renewable Energy in South Sulawesi

NASA Astrophysics Data System (ADS)

Fadliah Baso, Nur; Chaerah Gunadin, Indar; Yusran

2018-03-01

Renewable energy sources need to be developed to maintain the electric energy availability by utilizing oceanic energy, namely solar pond energy. This energy is highly influenced by several factors including salinity, air temperature and solar radiation. This study was focused on finding the potential of solar pond in South Sulawesi, a region with fairly high solar radiation and abundant salt water raw materials availability. The method used in this study was analyzing the values from the mathematic models of daily horizontal solar radiation, air temperature, wind speed, relative humidity and atmospheric pressure for the last 22 years which were finalized using MATLAB. The findings of this study will show the areas with good potentials to apply solar pond in South Sulawesi that can be utilized in various fields including power generator, industrial heating process, desalination and heating for biomass conversion.

Solar energy in California industry - Applications, characteristics and potential

NASA Technical Reports Server (NTRS)

Barbieri, R. H.; Pivirotto, D. S.

1978-01-01

Results of a survey to determine the potential applicability of solar thermal energy to industrial processes in California are presented. It is found that if the heat for all industrial processes at temperatures below 212 F were supplied by solar energy, total state energy consumption could be reduced by 100 trillion Btus (2%), while the use of solar energy in processes between 212 and 350 F could displace 500 trillion Btus. The issues and problems with which solar energy must contend are illustrated by a description of fluid milk processing operations. Solar energy application is found to be technically feasible for processes with thermal energy requirements below 212 F, with design, and degree of technical, economic and management feasibility being site specific. It is recommended that the state provide support for federal and industrial research, development and demonstration programs in order to stimulate acceptance of solar process heat application by industry.

State and location dependence of action potential metabolic cost in cortical pyramidal neurons.

PubMed

Hallermann, Stefan; de Kock, Christiaan P J; Stuart, Greg J; Kole, Maarten H P

2012-06-03

Action potential generation and conduction requires large quantities of energy to restore Na(+) and K(+) ion gradients. We investigated the subcellular location and voltage dependence of this metabolic cost in rat neocortical pyramidal neurons. Using Na(+)/K(+) charge overlap as a measure of action potential energy efficiency, we found that action potential initiation in the axon initial segment (AIS) and forward propagation into the axon were energetically inefficient, depending on the resting membrane potential. In contrast, action potential backpropagation into dendrites was efficient. Computer simulations predicted that, although the AIS and nodes of Ranvier had the highest metabolic cost per membrane area, action potential backpropagation into the dendrites and forward propagation into axon collaterals dominated energy consumption in cortical pyramidal neurons. Finally, we found that the high metabolic cost of action potential initiation and propagation down the axon is a trade-off between energy minimization and maximization of the conduction reliability of high-frequency action potentials.

Minimizing temperature instability of heat recovery hot water system utilizing optimized thermal energy storage

NASA Astrophysics Data System (ADS)

Suamir, I. N.; Sukadana, I. B. P.; Arsana, M. E.

2018-01-01

One energy-saving technology that starts gaining attractive for hotel industry application in Indonesia is the utilization of waste heat of a central air conditioning system to heat water for domestic hot water supply system. Implementing the technology for such application at a hotel was found that hot water capacity generated from the heat recovery system could satisfy domestic hot water demand of the hotel. The gas boilers installed in order to back up the system have never been used. The hot water supply, however, was found to be instable with hot water supply temperature fluctuated ranging from 45 °C to 62 °C. The temperature fluctuations reaches 17 °C, which is considered instable and can reduce hot water usage comfort level. This research is aimed to optimize the thermal energy storage in order to minimize the temperature instability of heat recovery hot water supply system. The research is a case study approach based on cooling and hot water demands of a hotel in Jakarta-Indonesia that has applied water cooled chillers with heat recovery systems. The hotel operation with 329 guest rooms and 8 function rooms showed that hot water production in the heat recovery system completed with 5 m3 thermal energy storage (TES) could not hold the hot water supply temperature constantly. The variations of the cooling demand and hot water demands day by day were identified. It was found that there was significant mismatched of available time (hours) between cooling demand which is directly correlated to the hot water production from the heat recovery system and hot water usage. The available TES system could not store heat rejected from the condenser of the chiller during cooling demand peak time between 14.00 and 18.00 hours. The extra heat from the heat recovery system consequently increases the temperature of hot water up to 62 °C. It is about 12 K above 50 °C the requirement hot water temperature of the hotel. In contrast, the TES could not deliver proper

The Potential for Renewable Energy Development to Benefit Restoration of the Salton Sea. Analysis of Technical and Market Potential

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

Gagne, Douglas; Haase, Scott; Oakleaf, Brett

This report summarizes the potential for renewable energy development in the Salton Sea region, as well as the potential for revenues from this development to contribute financially to Salton Sea restoration costs. It considers solar, geothermal, biofuels or nutraceutical production from algae pond cultivation, desalination using renewable energy, and mineral recovery from geothermal fluids.

Potential structural material problems in a hydrogen energy system

NASA Technical Reports Server (NTRS)

Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, B.; Howard, F. S.; Swisher, J. H.

1975-01-01

Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - were identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described.

Geospatial Analysis of Renewable Energy Technical Potential on Tribal Lands

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

Doris, E.; Lopez, A.; Beckley, D.

2013-02-01

This technical report uses an established geospatial methodology to estimate the technical potential for renewable energy on tribal lands for the purpose of allowing Tribes to prioritize the development of renewable energy resources either for community scale on-tribal land use or for revenue generating electricity sales.

Constrained minimization of smooth functions using a genetic algorithm

NASA Technical Reports Server (NTRS)

Moerder, Daniel D.; Pamadi, Bandu N.

1994-01-01

The use of genetic algorithms for minimization of differentiable functions that are subject to differentiable constraints is considered. A technique is demonstrated for converting the solution of the necessary conditions for a constrained minimum into an unconstrained function minimization. This technique is extended as a global constrained optimization algorithm. The theory is applied to calculating minimum-fuel ascent control settings for an energy state model of an aerospace plane.

A Molecular Dynamics Simulation of the Turbulent Couette Minimal Flow Unit

NASA Astrophysics Data System (ADS)

Smith, Edward

2016-11-01

What happens to turbulent motions below the Kolmogorov length scale? In order to explore this question, a 300 million molecule Molecular Dynamics (MD) simulation is presented for the minimal Couette channel in which turbulence can be sustained. The regeneration cycle and turbulent statistics show excellent agreement to continuum based computational fluid dynamics (CFD) at Re=400. As MD requires only Newton's laws and a form of inter-molecular potential, it captures a much greater range of phenomena without requiring the assumptions of Newton's law of viscosity, thermodynamic equilibrium, fluid isotropy or the limitation of grid resolution. The fundamental nature of MD means it is uniquely placed to explore the nature of turbulent transport. A number of unique insights from MD are presented, including energy budgets, sub-grid turbulent energy spectra, probability density functions, Lagrangian statistics and fluid wall interactions. EPSRC Post Doctoral Prize Fellowship.

Conversion of laser energy to gas kinetic energy

NASA Technical Reports Server (NTRS)

Caledonia, G. E.

1976-01-01

Techniques for the gas phase absorption of laser radiation for ultimate conversion to gas kinetic energy are discussed. Particular emphasis is placed on absorption by the vibration rotation bands of diatomic molecules at high pressures. This high pressure absorption appears to offer efficient conversion of laser energy to gas translational energy. Bleaching and chemical effects are minimized and the variation of the total absorption coefficient with temperature is minimal.

IBS and Potential Luminosity Improvement for RHIC Operation Below Transition Energy

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

Fedotov,A.

There is a strong interest in low-energy RHIC operations in the single-beam total energy range of 2.5-25 GeV/nucleon [1-3]. Collisions in this energy range, much of which is below nominal RHIC injection energy, will help to answer one of the key questions in the field of QeD about the existence and location of a critical point on the QCD phase diagram [4]. There have been several short test runs during 2006-2008 RHIC operations to evaluate RHIC operational challenges at these low energies [5]. Beam lifetimes observed during the test runs were limited by machine nonlinearities. This performance limit can bemore » improved with sufficient machine tuning. The next luminosity limitation comes from transverse and longitudinal Intra-beam Scattering (IBS), and ultimately from the space-charge limit. Detailed discussion of limiting beam dynamics effects and possible luminosity improvement with electron cooling can be found in Refs. [6-8]. For low-energy RHIC operation, particle losses from the RF bucket are of particular concern since the longitudinal beam size is comparable to the existing RF bucket at low energies. However, operation below transition energy allows us to exploit an Intra-beam Scattering (IBS) feature that drives the transverse and longitudinal beam temperatures towards equilibrium by minimizing the longitudinal diffusion rate using a high RF voltage. Simulation studies were performed with the goal to understand whether one can use this feature of IBS to improve luminosity of RHIC collider at low-energies. This Note presents results of simulations which show that additional luminosity improvement for low-energy RHIC project may be possible with high RF voltage from a 56 MHz superconducting RF cavity that is presently under development for RHIC.« less

Energy gap in graphene nanoribbons with structured external electric potentials

NASA Astrophysics Data System (ADS)

Apel, W.; Pal, G.; Schweitzer, L.

2011-03-01

The electronic properties of graphene zigzag nanoribbons with electrostatic potentials along the edges are investigated. Using the Dirac-fermion approach, we calculate the energy spectrum of an infinitely long nanoribbon of finite width w, terminated by Dirichlet boundary conditions in the transverse direction. We show that a structured external potential that acts within the edge regions of the ribbon can induce a spectral gap and thus switch the nanoribbon from metallic to insulating behavior. The basic mechanism of this effect is the selective influence of the external potentials on the spinorial wave functions that are topological in nature and localized along the boundary of the graphene nanoribbon. Within this single-particle description, the maximal obtainable energy gap is Emax∝πℏvF/w, i.e., ≈0.12 eV for w=15 nm. The stability of the spectral gap against edge disorder and the effect of disorder on the two-terminal conductance is studied numerically within a tight-binding lattice model. We find that the energy gap persists as long as the applied external effective potential is larger than ≃0.55×W, where W is a measure of the disorder strength. We argue that there is a transport gap due to localization effects even in the absence of a spectral gap.

Mission and status of the US Department of Energy's battery energy storage program

NASA Astrophysics Data System (ADS)

Quinn, J. E.; Hurwitch, J. W.; Landgrebe, A. R.; Hauser, S. G.

1985-05-01

The mission of the US Department of Energy's battery research program has evolved to reflect the changing conditions of the world energy economy and the national energy policy. The battery energy storage program supports the goals of the National Energy Policy Plan (FY 1984). The goals are to provide an adequate supply of energy at reasonable costs, minimize federal control and involvement in the energy marketplace, promote a balanced and mixed energy resource system, and facilitate technology transfer from the public to the private sector. This paper describes the history of the battery energy storage program and its relevance to the national interest. Potential market applications for battery energy storage are reviewed, and each technology, its goals, and its current technical status are described. The paper concludes by describing the strategy developed to ensure effective technology transfer to the private sector and reviewing past significant accomplishments.

The Parisi Formula has a Unique Minimizer

NASA Astrophysics Data System (ADS)

Auffinger, Antonio; Chen, Wei-Kuo

2015-05-01

In 1979, Parisi (Phys Rev Lett 43:1754-1756, 1979) predicted a variational formula for the thermodynamic limit of the free energy in the Sherrington-Kirkpatrick model, and described the role played by its minimizer. This formula was verified in the seminal work of Talagrand (Ann Math 163(1):221-263, 2006) and later generalized to the mixed p-spin models by Panchenko (Ann Probab 42(3):946-958, 2014). In this paper, we prove that the minimizer in Parisi's formula is unique at any temperature and external field by establishing the strict convexity of the Parisi functional.

Forecasting and evaluating patterns of energy development in southwestern Wyoming

USGS Publications Warehouse

Garman, Steven L.

2015-01-01

The effects of future oil and natural gas development in southwestern Wyoming on wildlife populations are topical to conservation of the sagebrush steppe ecosystem. To aid in understanding these potential effects, the U.S. Geological Survey developed an Energy Footprint simulation model that forecasts the amount and pattern of energy development under different assumptions of development rates and well-drilling methods. The simulated disturbance patterns produced by the footprint model are used to assess the potential effects on wildlife habitat and populations. A goal of this modeling effort is to use measures of energy production (number of simulated wells), well-pad and road-surface disturbance, and potential effects on wildlife to identify build-out designs that minimize the physical and ecological footprint of energy development for different levels of energy production and development costs.

Minimal massive 3D gravity

NASA Astrophysics Data System (ADS)

Bergshoeff, Eric; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.

2014-07-01

We present an alternative to topologically massive gravity (TMG) with the same ‘minimal’ bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new ‘minimal massive gravity’ has both a positive energy graviton and positive central charges for the asymptotic AdS-boundary conformal algebra.

Development of an Empirical Model for Optimization of Machining Parameters to Minimize Power Consumption

NASA Astrophysics Data System (ADS)

Kant Garg, Girish; Garg, Suman; Sangwan, K. S.

2018-04-01

The manufacturing sector consumes huge energy demand and the machine tools used in this sector have very less energy efficiency. Selection of the optimum machining parameters for machine tools is significant for energy saving and for reduction of environmental emission. In this work an empirical model is developed to minimize the power consumption using response surface methodology. The experiments are performed on a lathe machine tool during the turning of AISI 6061 Aluminum with coated tungsten inserts. The relationship between the power consumption and machining parameters is adequately modeled. This model is used for formulation of minimum power consumption criterion as a function of optimal machining parameters using desirability function approach. The influence of machining parameters on the energy consumption has been found using the analysis of variance. The validation of the developed empirical model is proved using the confirmation experiments. The results indicate that the developed model is effective and has potential to be adopted by the industry for minimum power consumption of machine tools.

Notepad-like triboelectric generator for efficiently harvesting low-velocity motion energy by interconversion between kinetic energy and elastic potential energy.

PubMed

Liu, Guanlin; Leng, Qiang; Lian, Jiawei; Guo, Hengyu; Yi, Xi; Hu, Chenguo

2015-01-21

Great attention has been paid to nanogenerators that harvest energy from ambient environments lately. In order to give considerable output current, most nanogenerators require high-velocity motion that in most cases can hardly be provided in our daily life. Here we report a notepad-like triboelectric generator (NTEG), which uses simple notepad-like structure to generate elastic deformation so as to turn a low-velocity kinetic energy into high-velocity kinetic energy through the conversion of elastic potential energy. Therefore, the NTEG can achieve high current output under low-velocity motion, which completely distinguishes it from tribogenerators previously reported. The factors that may affect the output performance are explored, including the number of slices, active length of slice, press speed, and vertical displacement. In addition, the working mechanism is systematically studied, indicating that the efficiency of the generator can be greatly enhanced by interconversion between kinetic energy and elastic potential energy. The short-circuit current, the open-circuit voltage, and power density are 205 μA and 470 V and 9.86 W/m(2), respectively, which is powerful enough to light up hundreds of light-emitting diodes (LEDs) and charge a commercial capacitor. Besides, NTEGs have been successfully applied to a self-powered door monitor.

An assessment of wind energy potential in Iberia under climate change

NASA Astrophysics Data System (ADS)

Liberato, Margarida L. R.; Santos, João A.; Rochinha, Carlos; Reyers, Mark; Pinto, Joaquim G.

2015-04-01

Wind energy potential in Iberia is assessed for recent-past (1961-2000) and future (2041-2070) climates. For recent-past, a COSMO-CLM simulation driven by ERA-40 is used. COSMO-CLM simulations driven by ECHAM5 following the A1B scenario are used for future projections. A 2 MW rated power wind turbine is selected. Mean potentials, inter-annual variability and irregularity are discussed on annual/seasonal scales and on a grid resolution of 20 km. For detailed regional assessments eight target sites are considered. For recent-past conditions, the highest daily mean potentials are found in winter over northern and eastern Iberia, particularly on high-elevation or coastal regions. In northwestern Iberia, daily potentials frequently reach maximum wind energy output (50 MWh day-1), particularly in winter. Southern Andalucía reveals high potentials throughout the year, whereas the Ebro valley and central-western coast show high potentials in summer. The irregularity in annual potentials is moderate (<15% of mean output), but exacerbated in winter (40%). Climate change projections show significant decreases over most of Iberia (<2 MWh day-1). The strong enhancement of autumn potentials in Southern Andalucía is noteworthy (>2 MWh day-1). The northward displacement of North Atlantic westerly winds (autumn-spring) and the strengthening of easterly flows (summer) are key drivers of future projections. Santos, J.A.; Rochinha, C.; Liberato, M.L.R.; Reyers, M.; Pinto, J.G. (2015) Projected changes in wind energy potentials over Iberia. Renewable Energy, 75, 1: 68-80. doi: 10.1016/j.renene.2014.09.026 Acknowledgements: This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER-019524 (PTDC/AAC-CLI/121339/2010).

New methods in the Newtonian potential theory. I - The representation of the potential energy of homogeneous gravitating bodies by converging bodies

NASA Astrophysics Data System (ADS)

Kondrat'ev, B. P.

1993-06-01

A method is developed for the representation of the potential energy of homogeneous gravitating, as well as electrically charged, bodies in the form of special series. These series contain members consisting of products of the corresponding coefficients appearing in the expansion of external and internal Newtonian potentials in Legendre polynomial series. Several versions of the representation of potential energy through these series are possible. A formula which expresses potential energy not as a volume integral, as is the convention, but as an integral over the body surface is derived. The method is tested for the particular cases of sphere and ellipsoid, and the convergence of the found series is shown.

Energy balance during underwater implosion of ductile metallic cylinders.

PubMed

Chamberlin, Ryan E; Guzas, Emily L; Ambrico, Joseph M

2014-11-01

Energy-based metrics are developed and applied to a numerical test case of implosion of an underwater pressure vessel. The energy metrics provide estimates of the initial energy in the system (potential energy), the energy released into the fluid as a pressure pulse, the energy absorbed by the imploding structure, and the energy absorbed by air trapped within the imploding structure. The primary test case considered is the implosion of an aluminum cylinder [diameter: 2.54 cm (1 in.), length: 27.46 cm (10.81 in.)] that collapses flat in a mode-2 shape with minimal fracture. The test case indicates that the structure absorbs the majority (92%) of the initial energy in the system. Consequently, the energy emitted as a pressure pulse into the fluid is a small fraction, approximately 5%, of the initial energy. The energy absorbed by the structure and the energy emitted into the fluid are calculated for additional simulations of underwater pressure vessel implosions. For all cases investigated, there is minimal fracture in the collapse, the structure absorbs more than 80% of the initial energy of the system, and the released pressure pulse carries away less than 6% of the initial energy.

On inflation with non-minimal coupling

NASA Astrophysics Data System (ADS)

Hertzberg, Mark P.

2010-11-01

A simple realization of inflation consists of adding the following operators to the Einstein-Hilbert action: ( ∂ϕ)2, λϕ 4, and ξϕ 2 R , with ξ a large non-minimal coupling. Recently there has been much discussion as to whether such theories make sense quantum mechanically and if the inflaton ϕ can also be the Standard Model Higgs. In this work we answer these questions. Firstly, for a single scalar ϕ, we show that the quantum field theory is well behaved in the pure gravity and kinetic sectors, since the quantum generated corrections are small. However, the theory likely breaks down at m Pl /ξ due to scattering provided by the self-interacting potential λϕ 4. Secondly, we show that the theory changes for multiple scalars overrightarrow φ with non-minimal coupling ξ overrightarrow φ \\cdot overrightarrow φ mathcal{R} , since this introduces qualitatively new interactions which manifestly generate large quantum corrections even in the gravity and kinetic sectors, spoiling the theory for energies ≳ m Pl /ξ. Since the Higgs doublet of the Standard Model includes the Higgs boson and 3 Goldstone bosons, it falls into the latter category and therefore its validity is manifestly spoiled. We show that these conclusions hold in both the Jordan and Einstein frames and describe an intuitive analogy in the form of the pion Lagrangian. We also examine the recent claim that curvature-squared inflation models fail quantum mechanically. Our work appears to go beyond the recent discussions.

Plateau inflation from random non-minimal coupling

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

Broy, Benedict J.; Coone, Dries; Theoretische Natuurkunde,Vrije Universiteit Brussel and The International Solvay Institutes,Pleinlaan 2, B-1050 Brussels

A generic non-minimal coupling can push any higher-order terms of the scalar potential sufficiently far out in field space to yield observationally viable plateau inflation. We provide analytic and numerical evidence that this generically happens for a non-minimal coupling strength ξ of the order N{sub e}{sup 2}. In this regime, the non-minimally coupled field is sub-Planckian during inflation and is thus protected from most higher-order terms. For larger values of ξ, the inflationary predictions converge towards the sweet spot of PLANCK. The latter includes ξ≃10{sup 4} obtained from CMB normalization arguments, thus providing a natural explanation for the inflationary observablesmore » measured.« less

Potential reduction of energy consumption in public university library

NASA Astrophysics Data System (ADS)

Noranai, Z.; Azman, ADF

2017-09-01

Efficient electrical energy usage has been recognized as one of the important factor to reduce cost of electrical energy consumption. Various parties have been emphasized about the importance of using electrical energy efficiently. Inefficient usage of electrical energy usage lead to biggest factor increasing of administration cost in Universiti Tun Hussein Onn Malaysia. With this in view, a project the investigate potential reduction electrical energy consumption in Universiti Tun Hussein Onn Malaysia was carried out. In this project, a case study involving electrical energy consumption of Perpustakaan Tunku Tun Aminah was conducted. The scopes of this project are to identify energy consumption in selected building and to find the factors that contributing to wastage of electrical energy. The MS1525:2001, Malaysian Standard - Code of practice on energy efficiency and use of renewable energy for non-residential buildings was used as reference. From the result, 4 saving measure had been proposed which is change type of the lamp, install sensor, decrease the number of lamp and improve shading coefficient on glass. This saving measure is suggested to improve the efficiency of electrical energy consumption. Improve of human behaviour toward saving energy measure can reduce 10% from the total of saving cost while on building technical measure can reduce 90% from total saving cost.

Energy savings potential from improved building controls for the US commercial building sector

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

Fernandez, Nick; Katipamula, Srinivas; Wang, Weimin

The U.S. Department of Energy’s (DOE’s) Building Technologies Office (BTO) sponsored a study to determine the potential national savings achievable in the commercial building sector through widespread deployment of best practice controls, elimination of system and component faults, and use of better sensing. Detailed characterization of potential savings was one source of input to set research, development, and deployment (RD&D) goals in the field of building sensors and controls. DOE’s building energy simulation software, EnergyPlus, was employed to estimate the potential savings from 34 measures in 9 building types and across 16 climates representing almost 57% of commercial building sectormore » energy consumption. In addition to estimating savings from individual measures, three packages of measures were created to estimate savings from the packages. These packages represented an 1) efficient building, 2) typical building, and 3) inefficient building. To scale the results from individual measures or a package to the national scale, building weights by building type and climate locations from the Energy Information Administration’s 2012 Commercial Building Energy Consumption Survey (CBECS) were used. The results showed significant potential for energy savings across all building types and climates. The total site potential savings from individual measures by building type and climate location ranged between 0% and 25%. The total site potential savings by building type aggregated across all climates (using the CBECS building weights) for each measure varied between 0% and 16%. The total site potential savings aggregated across all building types and climates for each measure varied between 0% and 11%. Some individual measures had negative savings because correcting underlying operational problems (e.g., inadequate ventilation) resulted in increased energy consumption. When combined into packages, the overall national savings potential is estimated to be

Comparison of Degrees of Potential-Energy-Surface Anharmonicity for Complexes and Clusters with Hydrogen Bonds

NASA Astrophysics Data System (ADS)

Kozlovskaya, E. N.; Doroshenko, I. Yu.; Pogorelov, V. E.; Vaskivskyi, Ye. V.; Pitsevich, G. A.

2018-01-01

Previously calculated multidimensional potential-energy surfaces of the MeOH monomer and dimer, water dimer, malonaldehyde, formic acid dimer, free pyridine-N-oxide/trichloroacetic acid complex, and protonated water dimer were analyzed. The corresponding harmonic potential-energy surfaces near the global minima were constructed for series of clusters and complexes with hydrogen bonds of different strengths based on the behavior of the calculated multidimensional potential-energy surfaces. This enabled the introduction of an obvious anharmonicity parameter for the calculated potential-energy surfaces. The anharmonicity parameter was analyzed as functions of the size of the analyzed area near the energy minimum, the number of points over which energies were compared, and the dimensionality of the solved vibrational problem. Anharmonicity parameters for potential-energy surfaces in complexes with strong, medium, and weak H-bonds were calculated under identical conditions. The obtained anharmonicity parameters were compared with the corresponding diagonal anharmonicity constants for stretching vibrations of the bridging protons and the lengths of the hydrogen bridges.

Dimensional oscillation. A fast variation of energy embedding gives good results with the AMBER potential energy function.

PubMed

Snow, M E; Crippen, G M

1991-08-01

The structure of the AMBER potential energy surface of the cyclic tetrapeptide cyclotetrasarcosyl is analyzed as a function of the dimensionality of coordinate space. It is found that the number of local energy minima decreases as the dimensionality of the space increases until some limit at which point equipotential subspaces appear. The applicability of energy embedding methods to finding global energy minima in this type of energy-conformation space is explored. Dimensional oscillation, a computationally fast variant of energy embedding is introduced and found to sample conformation space widely and to do a good job of finding global and near-global energy minima.

Morcellator's Port-site Metastasis of a Uterine Smooth Muscle Tumor of Uncertain Malignant Potential After Minimally Invasive Myomectomy.

PubMed

Bogani, Giorgio; Ditto, Antonino; Martinelli, Fabio; Signorelli, Mauro; Chiappa, Valentina; Lorusso, Domenica; Sabatucci, Ilaria; Carcangiu, Maria L; Fiore, Marco; Gronchi, Alessandro; Raspagliesi, Francesco

2016-01-01

Since the safety warning from the US Food and Drug Administration on the use of power morcellators, minimally invasive procedures involving the removal of uterine myomas and large uteri are under scrutiny. Growing evidence suggests that morcellation of undiagnosed uterine malignancies is associated with worse survival outcomes of patients affected by uterine sarcoma. However, to date, only limited data regarding morcellation of low-grade uterine neoplasms are available. In the present article, we reported a case of a (morcellator) port-site implantation of a smooth muscle tumor that occurred 6 years after laparoscopic morcellation of a uterine smooth muscle tumor of uncertain potential. This case highlights the effects of intra-abdominal morcellation, even in low-grade uterine neoplasms. Caution should be used when determining techniques for tissue extraction; the potential adverse consequences of morcellation should be more fully explored. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Fourfold Clusters of Rovibrational Energies in H2Te Studied With an Ab Initio Potential Energy Function

NASA Technical Reports Server (NTRS)

Jensen, Per; Li, Yan; Hirsch, Gerhard; Buenker, Robert J.; Lee, Timothy J.; Arnold, James O. (Technical Monitor)

1994-01-01

We report an ab initio investigation of the cluster effect (i.e., the formation of nearly degenerate, four member groups of rotation-vibration energy levels at higher J and K(sub a). values) in the H2Te molecule. The potential energy function has been calculated ab initio at a total of 334 molecular geometries by means of the CCSD(T) method where the (1s-4f) core electrons of Te were described by an effective core potential. The values of the potential energy function obtained cover the region up to around 10,000/cm above the equilibrium energy. On the basis of the ab initio potential, the rotation-vibration energy spectra of H2Te-130 and its deuterated isotopomers have been calculated with the MORBID (Morse Oscillator Rigid Bender Internal Dynamics) Hamiltonian and computer program. In particular, we have calculated the rotational energy manifolds for J less than or = 40 in the vibrational ground state, the upsilon(sub 2) state, the "first triad" (the upsilon(sub l)/upsilon(sub 3)/2upsilon(sub 2) interacting vibrational states), and the "second triad" (the upsilon(sub 1) + upsilon(sub 2/upsilon(sub 2) + upsilon(sub 3)/3upsilon(sub 2) states) of H2Te-130. We find that the cluster formation in H2Te is very similar to those of of H2Se and H2S, which we have studied previously. However, contrary to semiclassical predictions, we do not determine any significant displacement of the clusters towards lower J values relative to H2Se. Hence the experimental observation of the cluster states in H2Te will be at least as difficult as in H2Se.

Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf

PubMed Central

Simonin, Kevin A.; Burns, Emily; Choat, Brendan; Barbour, Margaret M.; Dawson, Todd E.; Franks, Peter J.

2015-01-01

Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem–leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO2 concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO2 concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO2 on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem–leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO2 assimilation rate over the diurnal course of evaporative demand. PMID:25547915

The Dominant Folding Route Minimizes Backbone Distortion in SH3

PubMed Central

Lammert, Heiko; Noel, Jeffrey K.; Onuchic, José N.

2012-01-01

Energetic frustration in protein folding is minimized by evolution to create a smooth and robust energy landscape. As a result the geometry of the native structure provides key constraints that shape protein folding mechanisms. Chain connectivity in particular has been identified as an essential component for realistic behavior of protein folding models. We study the quantitative balance of energetic and geometrical influences on the folding of SH3 in a structure-based model with minimal energetic frustration. A decomposition of the two-dimensional free energy landscape for the folding reaction into relevant energy and entropy contributions reveals that the entropy of the chain is not responsible for the folding mechanism. Instead the preferred folding route through the transition state arises from a cooperative energetic effect. Off-pathway structures are penalized by excess distortion in local backbone configurations and contact pair distances. This energy cost is a new ingredient in the malleable balance of interactions that controls the choice of routes during protein folding. PMID:23166485

Criticality of the electron-nucleus cusp condition to local effective potential-energy theories

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

Pan Xiaoyin; Sahni, Viraht; Graduate School of the City University of New York, 360 Fifth Avenue, New York, New York 10016

2003-01-01

Local(multiplicative) effective potential energy-theories of electronic structure comprise the transformation of the Schroedinger equation for interacting Fermi systems to model noninteracting Fermi or Bose systems whereby the equivalent density and energy are obtained. By employing the integrated form of the Kato electron-nucleus cusp condition, we prove that the effective electron-interaction potential energy of these model fermions or bosons is finite at a nucleus. The proof is general and valid for arbitrary system whether it be atomic, molecular, or solid state, and for arbitrary state and symmetry. This then provides justification for all prior work in the literature based on themore » assumption of finiteness of this potential energy at a nucleus. We further demonstrate the criticality of the electron-nucleus cusp condition to such theories by an example of the hydrogen molecule. We show thereby that both model system effective electron-interaction potential energies, as determined from densities derived from accurate wave functions, will be singular at the nucleus unless the wave function satisfies the electron-nucleus cusp condition.« less

Application of free energy minimization to the design of adaptive multi-agent teams

NASA Astrophysics Data System (ADS)

Levchuk, Georgiy; Pattipati, Krishna; Fouse, Adam; Serfaty, Daniel

2017-05-01

Many novel DoD missions, from disaster relief to cyber reconnaissance, require teams of humans and machines with diverse capabilities. Current solutions do not account for heterogeneity of agent capabilities, uncertainty of team knowledge, and dynamics of and dependencies between tasks and agent roles, resulting in brittle teams. Most importantly, the state-of-the-art team design solutions are either centralized, imposing role and relation assignment onto agents, or completely distributed, suitable for only homogeneous organizations such as swarms. Centralized design models can't provide insights for team's self-organization, i.e. adapting team structure over time in distributed collaborative manner by team members with diverse expertise and responsibilities. In this paper we present an information-theoretic formalization of team composition and structure adaptation using a minimization of variational free energy. The structure adaptation is obtained in an iterative distributed and collaborative manner without the need for centralized control. We show that our model is lightweight, predictive, and produces team structures that theoretically approximate an optimal policy for team adaptation. Our model also provides a unique coupling between the structure and action policy, and captures three essential processes of learning, perception, and control.

Energy generation potential from coals of the Charqueadas Coalfield, RS, Brazil

NASA Astrophysics Data System (ADS)

Correa da Silva, Z. C.; Heemann, R.; Castro, L.; Ketzer, J. M.

2009-04-01

Three coal seams, I2B (Inferior 2), I1F (Inferior 1) and MB, from the Charqueadas Coalfield located in the central-east region of the State of Rio Grande do Sul, Southern Brazil were studied on the basis of geological, petrographic, chemical and geochemical techniques and correlated to the SR1, SR2 and SR3 coal seams from the Santa Rita Coalfield. The Charqueadas Coalfield reserves reach 2,993x106 metric tons of coal distributed in six coal seams. The study of sedimentary and organic facies is made on the subsurface data from five boreholes drilled in the area. There show a well marked lateral facies change from sub aquatic to sub aerial environment, conditioned by both the water level variations and the irregular palaeotopography of the basement. The coals change from limnic to forest-terrestrial moor types characterized by variations of composition in terms of macerals, microlithotypes and mineral matter. The coals are rich in mineral matter (28 to 40%); the vitrinite content reaches 50 %, inertinite 44 % and liptinite varies from 10 to 30 %, in mineral matter free basis. Among the microlithotypes carbominerite and vitrite are predominant. Rank studies carried out by different methods (vitrinite reflectance, max and red-green quotient among others) gave conflicting results, which are explained by the strong bituminization of the vitrinite. However, agreement between fluorescence measurements and organic geochemical parameters (e.g. CPI values) confirm that the coals are of a High Volatile Bituminous B/C (ASTM) or Gasflammkohle (DIN) rank. Based on these characteristics, the Charqueadas coal seams show great potential for use in Underground Coal Gasification (UCG) and Enhanced Coalbed Methane (ECBM) projects. Nowadays the state of Rio Grande do Sul is rapidly growing and needs to increase the energy efficiency to attend the industrial demands, filling the gap between supply and energy generation. As with conventional IGCC, UCG gas can be used to generate

Characteristics of Ampel bamboo as a biomass energy source potential in Bali

NASA Astrophysics Data System (ADS)

Sucipta, M.; Putra Negara, D. N. K.; Tirta Nindhia, T. G.; Surata, I. W.

2017-05-01

Currently, non-renewable fossil energy dominates utilization of the world energy need for many applications. Efforts has been developed to find alternative renewable energy sources, due to fossil energy availability is diminishing. And one of renewable energy source is from biomass. The aim of this research is to determine characteristics of the Ampel bamboo (Bambusa vulgaris) as an energy potential of biomass. The Ampel bamboo’s characteristics possessed are evaluated based on its chemical composition; moisture, volatile, ash, and fixed carbon through proximate analysis; and also carbon, hydrogen and nitrogen content through ultimate analysis. From the Thermo-gravimetric analysis (TGA) indicates that Ampel bamboo contains of about 18.10% hemicelluloses, 47.75% cellulose and 18.86% lignin. While from the ultimate analysis results in the content of carbon, hydrogen, and Nitrogen of Ampel bamboo are 39.75%, 5.75% and 0% respectively. With such characteristics, it indicates that Ampel bamboo has an attractive potential as a renewable energy source.

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

Scalar-fluid interacting dark energy: Cosmological dynamics beyond the exponential potential

NASA Astrophysics Data System (ADS)

Dutta, Jibitesh; Khyllep, Wompherdeiki; Tamanini, Nicola

2017-01-01

We extend the dynamical systems analysis of scalar-fluid interacting dark energy models performed in C. G. Boehmer et al., Phys. Rev. D 91, 123002 (2015), 10.1103/PhysRevD.91.123002 by considering scalar field potentials beyond the exponential type. The properties and stability of critical points are examined using a combination of linear analysis, computational methods and advanced mathematical techniques, such as center manifold theory. We show that the interesting results obtained with an exponential potential can generally be recovered also for more complicated scalar field potentials. In particular, employing power law and hyperbolic potentials as examples, we find late time accelerated attractors, transitions from dark matter to dark energy domination with specific distinguishing features, and accelerated scaling solutions capable of solving the cosmic coincidence problem.

The sea surface currents as a potential factor in the estimation and monitoring of wave energy potential

NASA Astrophysics Data System (ADS)

Zodiatis, George; Galanis, George; Nikolaidis, Andreas; Stylianoy, Stavros; Liakatas, Aristotelis

2015-04-01

The use of wave energy as an alternative renewable is receiving attention the last years under the shadow of the economic crisis in Europe and in the light of the promising corresponding potential especially for countries with extended coastline. Monitoring and studying the corresponding resources is further supported by a number of critical advantages of wave energy compared to other renewable forms, like the reduced variability and the easier adaptation to the general grid, especially when is jointly approached with wind power. Within the framework, a number of countries worldwide have launched research and development projects and a significant number of corresponding studies have been presented the last decades. However, in most of them the impact of wave-sea surface currents interaction on the wave energy potential has not been taken into account neglecting in this way a factor of potential importance. The present work aims at filling this gap for a sea area with increased scientific and economic interest, the Eastern Mediterranean Sea. Based on a combination of high resolution numerical modeling approach with advanced statistical tools, a detailed analysis is proposed for the quantification of the impact of sea surface currents, which produced from downscaling the MyOcean-FO regional data, to wave energy potential. The results although spatially sensitive, as expected, prove beyond any doubt that the wave- sea surface currents interaction should be taken into account for similar resource analysis and site selection approaches since the percentage of impact to the available wave power may reach or even exceed 20% at selected areas.

Modeling In-stream Tidal Energy Extraction and Its Potential Environmental Impacts

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

Yang, Zhaoqing; Wang, Taiping; Copping, Andrea

In recent years, there has been growing interest in harnessing in-stream tidal energy in response to concerns of increasing energy demand and to mitigate climate change impacts. While many studies have been conducted to assess and map tidal energy resources, efforts for quantifying the associated potential environmental impacts have been limited. This paper presents the development of a tidal turbine module within a three-dimensional unstructured-grid coastal ocean model and its application for assessing the potential environmental impacts associated with tidal energy extraction. The model is used to investigate in-stream tidal energy extraction and associated impacts on estuarine hydrodynamic and biologicalmore » processes in a tidally dominant estuary. A series of numerical experiments with varying numbers and configurations of turbines installed in an idealized estuary were carried out to assess the changes in the hydrodynamics and biological processes due to tidal energy extraction. Model results indicated that a large number of turbines are required to extract the maximum tidal energy and cause significant reduction of the volume flux. Preliminary model results also indicate that extraction of tidal energy increases vertical mixing and decreases flushing rate in a stratified estuary. The tidal turbine model was applied to simulate tidal energy extraction in Puget Sound, a large fjord-like estuary in the Pacific Northwest coast.« less

Consequences of converting graded to action potentials upon neural information coding and energy efficiency.

PubMed

Sengupta, Biswa; Laughlin, Simon Barry; Niven, Jeremy Edward

2014-01-01

Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na(+) and K(+) channels, with generator potential and graded potential models lacking voltage-gated Na(+) channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na(+) channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a 'footprint' in the generator potential that obscures incoming signals. These three processes reduce information rates by ∼50% in generator potentials, to ∼3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation.

Solar Energy within the Central Valley, CA: Current Practices and Potential

NASA Astrophysics Data System (ADS)

Hoffacker, M. K.; Hernandez, R. R.; Allen, M. F.

2015-12-01

Utility-scale solar energy (USSE, ≥ 1 megawatt [MW]) systems are rapidly being deployed in the Central Valley of California, generating clean electricity and new job opportunities. Utility-scale solar energy systems require substantial quantities of land or space, often prompting an evaluation of environmental impacts and trade-offs when selecting their placement. Utilizing salt-contaminated agricultural land (as the sodium absorption and electrical conductivity values are unsuitably high), unsuitable for food production, and lands within the built environment (developed), can serve as a co-benefit opportunity when reclamation of these lands for USSE development is prioritized. In this study, we quantify the theoretical and generation-based solar energy potential for the Central Valley according to land-cover type, crop type, and for salt-contaminated lands. Further, we utilize the Carnegie Energy and Environmental Compatibility (CEEC) model to identify and prioritize solar energy, integrating environmental resource opportunities and constraints most relevant to the Central Valley. We use the CEEC model to generate a value-based environmental compatibility output for the Central Valley. The Central Valley extends across nearly 60,000 km2 of California with the potential of generating 21,800 - 30,300 TWh y-1 and 41,600 TWh y-1 of solar energy for photovoltaic (PV) and concentrating solar power (CSP), respectively. Pasture, hay, and cultivated crops comprise over half of the Central Valley, much of which is considered prime agriculture or of statewide or local importance for farming (28,200 km2). Together, approximately one-third of this region is salt-contaminated (16%) or developed (11%). This confers a generation-based potential of 5713 - 7891 TWh y-1 and 2770 TWh y-1 for PV and CSP, respectively. As energy, food, and land are inextricably linked, our study shows how land favorable for renewable energy systems can be used more effectively in places where land is

Comparisons of Adolescent and Parent Willingness to Participate in Minimal and Above Minimal Risk Pediatric Asthma Research Protocols

PubMed Central

Brody, Janet L.; Annett, Robert D.; Scherer, David G.; Perryman, Mandy L.; Cofrin, Keely M. W.

2007-01-01

Purpose Much has been written about conceptual concern for voluntary assent with children and adolescents. However, little empirical data exists examining the frequency with which, or context in which, adolescents and parents disagree on research participation decisions. The purpose of this study was to compare parent and adolescent willingness to participate in minimal and above minimal risk pediatric asthma research protocols. Method 36 adolescents diagnosed with asthma and one of their parents independently rated their willingness to participate in 9 pediatric asthma research protocol vignettes. The selected protocols were chosen by an expert panel as representative of typical minimal and above minimal risk pediatric asthma studies. Results Parents and adolescents were significantly less likely to agree to enroll in above minimal risk studies. However, this was qualified by a finding that adolescents were significantly more willing than parents to enroll in above minimal risk research. Across all 9 studies, parents and adolescents held concordant views on participation decisions approximately 60% of the time. Perception of potential study benefit was the most frequent reason provided for participation decisions by both parents and adolescents. Conclusion Parents and their adolescents report a consistent 40% discordance in their views about participating in asthma research across a variety of asthma research protocols, with adolescents more willing than their parents to enroll in above minimal risk studies. These differences of opinion highlight the need to carefully consider the process by which families are offered the option of adolescent research participation. PMID:16109343

Energy savings potential in air conditioners and chiller systems

DOE PAGES

Kaya, Durmus; Alidrisi, Hisham

2014-01-22

In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. Here, we also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: (1) installing higher efficiency air conditioners, (2) installing higher efficiency chillers, (3) duty cycling air conditioning units, and (4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment costmore » and pay back periods were calculated.« less

Use of minimal invasive extracorporeal circulation in cardiac surgery: principles, definitions and potential benefits. A position paper from the Minimal invasive Extra-Corporeal Technologies international Society (MiECTiS)

PubMed Central

Anastasiadis, Kyriakos; Murkin, John; Antonitsis, Polychronis; Bauer, Adrian; Ranucci, Marco; Gygax, Erich; Schaarschmidt, Jan; Fromes, Yves; Philipp, Alois; Eberle, Balthasar; Punjabi, Prakash; Argiriadou, Helena; Kadner, Alexander; Jenni, Hansjoerg; Albrecht, Guenter; van Boven, Wim; Liebold, Andreas; de Somer, Fillip; Hausmann, Harald; Deliopoulos, Apostolos; El-Essawi, Aschraf; Mazzei, Valerio; Biancari, Fausto; Fernandez, Adam; Weerwind, Patrick; Puehler, Thomas; Serrick, Cyril; Waanders, Frans; Gunaydin, Serdar; Ohri, Sunil; Gummert, Jan; Angelini, Gianni; Falk, Volkmar; Carrel, Thierry

2016-01-01

Minimal invasive extracorporeal circulation (MiECC) systems have initiated important efforts within science and technology to further improve the biocompatibility of cardiopulmonary bypass components to minimize the adverse effects and improve end-organ protection. The Minimal invasive Extra-Corporeal Technologies international Society was founded to create an international forum for the exchange of ideas on clinical application and research of minimal invasive extracorporeal circulation technology. The present work is a consensus document developed to standardize the terminology and the definition of minimal invasive extracorporeal circulation technology as well as to provide recommendations for the clinical practice. The goal of this manuscript is to promote the use of MiECC systems into clinical practice as a multidisciplinary strategy involving cardiac surgeons, anaesthesiologists and perfusionists. PMID:26819269

Turkey's High Temperature Geothermal Energy Resources and Electricity Production Potential

NASA Astrophysics Data System (ADS)

Bilgin, Ö.

2012-04-01

Turkey is in the first 7 countries in the world in terms of potential and applications. Geothermal energy which is an alternative energy resource has advantages such as low-cost, clean, safe and natural resource. Geothermal energy is defined as hot water and steam which is formed by heat that accumulated in various depths of the Earth's crust; with more than 20oC temperature and which contain more than fused minerals, various salts and gases than normal underground and ground water. It is divided into three groups as low, medium and high temperature. High-temperature fluid is used in electricity generation, low and medium temperature fluids are used in greenhouses, houses, airport runways, animal farms and places such as swimming pools heating. In this study high temperature geothermal fields in Turkey which is suitable for electricity production, properties and electricity production potential was investigated.

Rotational Energy Transfer of N2 Gas Determined Using a New Ab Initio Potential Energy Surface

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

1997-01-01

Rotational energy transfer between two N2 molecules is a fundamental process of some importance. Exchange is expected to play a role, but its importance is somewhat uncertain. Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows, laser operations, and linewidth analysis in nonintrusive laser diagnostics. A number of N2-N2 rigid rotor potential energy surface (PES) has been reported in the literature.

A minimally invasive blood-extraction system: elastic self-recovery actuator integrated with an ultrahigh- aspect-ratio microneedle.

PubMed

Li, Cheng Guo; Lee, Kwang; Lee, Chang Yeol; Dangol, Manita; Jung, Hyungil

2012-08-28

A minimally invasive blood-extraction system is fabricated by the integration of an elastic self-recovery actuator and an ultrahigh-aspect-ratio microneedle. The simple elastic self-recovery actuator converts finger force to elastic energy to provide power for blood extraction and transport without requiring an external source of power. This device has potential utility in the biomedical field within the framework of complete micro-electromechanical systems. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Training potential in minimally invasive surgery in a tertiary care, paediatric urology centre.

PubMed

Schroeder, R P J; Chrzan, R J; Klijn, A J; Kuijper, C F; Dik, P; de Jong, T P V M

2015-10-01

Minimally invasive surgery (MIS) is being utilized more frequently as a surgical technique in general surgery and in paediatric urology. It is associated with a steep learning curve. Currently, the centre does not offer a MIS training programme. It is hypothesized that the number of MIS procedures performed in the low-volume specialty of paediatric urology will offer insufficient training potential for surgeons. To assess the MIS training potential of a highly specialized, tertiary care, paediatric urology training centre that has been accredited by the Joint Committee of Paediatric Urology (JCPU). The clinical activity of the department was retrospectively reviewed by extracting the annual number of admissions, outpatient consultations and operative procedures. The operations were divided into open procedures and MIS. Major ablative procedures (nephrectomy) and reconstructive procedures (pyeloplasty) were analysed with reference to the patients' ages. The centre policy is not to perform major MIS in children who are under 2 years old or who weigh less than 12 kg. Every year, this institution provides approximately 4300 out-patient consultations, 600 admissions, and 1300 procedures under general anaesthesia for children with urological problems. In 2012, 35 patients underwent major intricate MIS: 16 pyeloplasties, eight nephrectomies and 11 operations for incontinence (seven Burch, and four bladder neck procedures). In children ≥2 years of age, 16/21 of the pyeloplasties and 8/12 of the nephrectomies were performed laparoscopically. The remaining MIS procedures included 25 orchidopexies and one intravesical ureteral reimplantation. There is no consensus on how to assess laparoscopic training. It would be valuable to reach a consensus on a standardized laparoscopic training programme in paediatric urology. Often training potential is based on operation numbers only. In paediatric urology no minimum requirement has been specified. The number of procedures quoted

Alaska's renewable energy potential.

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

Not Available

2009-02-01

This paper delivers a brief survey of renewable energy technologies applicable to Alaska's climate, latitude, geography, and geology. We first identify Alaska's natural renewable energy resources and which renewable energy technologies would be most productive. e survey the current state of renewable energy technologies and research efforts within the U.S. and, where appropriate, internationally. We also present information on the current state of Alaska's renewable energy assets, incentives, and commercial enterprises. Finally, we escribe places where research efforts at Sandia National Laboratories could assist the state of Alaska with its renewable energy technology investment efforts.

Upcrowding energy co-operatives - Evaluating the potential of crowdfunding for business model innovation of energy co-operatives.

PubMed

Dilger, Mathias Georg; Jovanović, Tanja; Voigt, Kai-Ingo

2017-08-01

Practice and theory have proven the relevance of energy co-operatives for civic participation in the energy turnaround. However, due to a still low awareness and changing regulation, there seems an unexploited potential of utilizing the legal form 'co-operative' in this context. The aim of this study is therefore to investigate the crowdfunding implementation in the business model of energy co-operatives in order to cope with the mentioned challenges. Based on a theoretical framework, we derive a Business Model Innovation (BMI) through crowdfunding including synergies and differences. A qualitative study design, particularly a multiple-case study of energy co-operatives, was chosen to prove the BMI and to reveal barriers. The results show that although most co-operatives are not familiar with crowdfunding, there is strong potential in opening up predominantly local structures to a broader group of members. Building on this, equity-based crowdfunding is revealed to be suitable for energy co-operatives as BMI and to accompany other challenges in the same way. Copyright © 2017 Elsevier Ltd. All rights reserved.

Minimizing calibration time using inter-subject information of single-trial recognition of error potentials in brain-computer interfaces.

PubMed

Iturrate, Iñaki; Montesano, Luis; Chavarriaga, Ricardo; del R Millán, Jose; Minguez, Javier

2011-01-01

One of the main problems of both synchronous and asynchronous EEG-based BCIs is the need of an initial calibration phase before the system can be used. This phase is necessary due to the high non-stationarity of the EEG, since it changes between sessions and users. The calibration process limits the BCI systems to scenarios where the outputs are very controlled, and makes these systems non-friendly and exhausting for the users. Although it has been studied how to reduce calibration time for asynchronous signals, it is still an open issue for event-related potentials. Here, we propose the minimization of the calibration time on single-trial error potentials by using classifiers based on inter-subject information. The results show that it is possible to have a classifier with a high performance from the beginning of the experiment, and which is able to adapt itself making the calibration phase shorter and transparent to the user.

Permutation invariant potential energy surfaces for polyatomic reactions using atomistic neural networks

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

Kolb, Brian; Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; Zhao, Bin

2016-06-14

The applicability and accuracy of the Behler-Parrinello atomistic neural network method for fitting reactive potential energy surfaces is critically examined in three systems, H + H{sub 2} → H{sub 2} + H, H + H{sub 2}O → H{sub 2} + OH, and H + CH{sub 4} → H{sub 2} + CH{sub 3}. A pragmatic Monte Carlo method is proposed to make efficient choice of the atom-centered mapping functions. The accuracy of the potential energy surfaces is not only tested by fitting errors but also validated by direct comparison in dynamically important regions and by quantum scattering calculations. Our results suggestmore » this method is both accurate and efficient in representing multidimensional potential energy surfaces even when dissociation continua are involved.« less

Minimal universal quantum heat machine.

PubMed

Gelbwaser-Klimovsky, D; Alicki, R; Kurizki, G

2013-01-01

In traditional thermodynamics the Carnot cycle yields the ideal performance bound of heat engines and refrigerators. We propose and analyze a minimal model of a heat machine that can play a similar role in quantum regimes. The minimal model consists of a single two-level system with periodically modulated energy splitting that is permanently, weakly, coupled to two spectrally separated heat baths at different temperatures. The equation of motion allows us to compute the stationary power and heat currents in the machine consistent with the second law of thermodynamics. This dual-purpose machine can act as either an engine or a refrigerator (heat pump) depending on the modulation rate. In both modes of operation, the maximal Carnot efficiency is reached at zero power. We study the conditions for finite-time optimal performance for several variants of the model. Possible realizations of the model are discussed.

Wave Energy Prize - 1/20th Testing - Sea Potential

DOE Data Explorer

Scharmen, Wesley

2016-09-23

Data from the 1/20th scale testing data completed on the Wave Energy Prize for the Sea Potential team, including the 1/20th scale test plan, raw test data, video, photos, and data analysis results. The top level objective of the 1/20th scale device testing is to obtain the necessary measurements required for determining Average Climate Capture Width per Characteristic Capital Expenditure (ACE) and the Hydrodynamic Performance Quality (HPQ), key metrics for determining the Wave Energy Prize (WEP) winners.

Critical insight into the influence of the potential energy surface on fission dynamics

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

Mazurek, K.; Grand Accelerateur National d'Ions Lourds; Schmitt, C.

The present work is dedicated to a careful investigation of the influence of the potential energy surface on the fission process. The time evolution of nuclei at high excitation energy and angular momentum is studied by means of three-dimensional Langevin calculations performed for two different parametrizations of the macroscopic potential: the Finite Range Liquid Drop Model (FRLDM) and the Lublin-Strasbourg Drop (LSD) prescription. Depending on the mass of the system, the topology of the potential throughout the deformation space of interest in fission is observed to noticeably differ within these two approaches, due to the treatment of curvature effects. Whenmore » utilized in the dynamical calculation as the driving potential, the FRLDM and LSD models yield similar results in the heavy-mass region, whereas the predictions can be strongly dependent on the Potential Energy Surface (PES) for medium-mass nuclei. In particular, the mass, charge, and total kinetic energy distributions of the fission fragments are found to be narrower with the LSD prescription. The influence of critical model parameters on our findings is carefully investigated. The present study sheds light on the experimental conditions and signatures well suited for constraining the parametrization of the macroscopic potential. Its implication regarding the interpretation of available experimental data is briefly discussed.« less

The potential impact of hydrogen energy use on the atmosphere

NASA Astrophysics Data System (ADS)

van Ruijven, B. J.; Lamarque, J. F.; van Vuuren, D. P.; Kram, T.; Eerens, H.

2009-04-01

Energy models show very different trajectories for future energy systems (partly as function of future climate policy). One possible option is a transition towards a hydrogen-based energy system. The potential impact of such hydrogen economy on atmospheric emissions is highly uncertain. On the one hand, application of hydrogen in clean fuel cells reduces emissions of local air pollutants, like SOx and NOx. On the other hand, emissions of hydrogen from system leakages are expected to change the atmospheric concentrations and behaviour (see also Price et al., 2007; Sanderson et al., 2003; Schultz et al., 2003; Tromp et al., 2003). The uncertainty arises from several sources: the expected use of hydrogen, the intensity of leakages and emissions, and the atmospheric chemical behaviour of hydrogen. Existing studies to the potential impacts of a hydrogen economy on the atmosphere mostly use hydrogen emission scenarios that are based on simple assumptions. This research combines two different modelling efforts to explore the range of impacts of hydrogen on atmospheric chemistry. First, the potential role of hydrogen in the global energy system and the related emissions of hydrogen and other air pollutants are derived from the global energy system simulation model TIMER (van Vuuren, 2007). A set of dedicated scenarios on hydrogen technology development explores the most pessimistic and optimistic cases for hydrogen deployment (van Ruijven et al., 2008; van Ruijven et al., 2007). These scenarios are combined with different assumptions on hydrogen emission factors. Second, the emissions from the TIMER model are linked to the NCAR atmospheric model (Lamarque et al., 2005; Lamarque et al., 2008), in order to determine the impacts on atmospheric chemistry. By combining an energy system model and an atmospheric model, we are able to consistently explore the boundaries of both hydrogen use, emissions and impacts on atmospheric chemistry. References: Lamarque, J.-F., Kiehl, J. T

Consequences of Converting Graded to Action Potentials upon Neural Information Coding and Energy Efficiency

PubMed Central

Sengupta, Biswa; Laughlin, Simon Barry; Niven, Jeremy Edward

2014-01-01

Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na+ and K+ channels, with generator potential and graded potential models lacking voltage-gated Na+ channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na+ channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a ‘footprint’ in the generator potential that obscures incoming signals. These three processes reduce information rates by ∼50% in generator potentials, to ∼3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation. PMID:24465197

Assessment of wave energy potential along the south coast of Java Island

NASA Astrophysics Data System (ADS)

Song, Qingyang; Mayerle, Roberto

2018-04-01

The south coast of Java Island has a great potential for wave energy. A long-term analysis of a 10-year wave dataset obtained from the ERA-Interim database is performed for preliminary wave energy assessment in this area, and it was seen that the annual median power is expected to exceed 20kW/m along the coast. A coastal wave model with an unstructured grid was run to reveal the wave conditions and to assess the wave energy potential along the coast in detail. The effect of swells and local wind on the wave conditions is investigated. Annual median wave power, water depth and distance from the coast are selected as criteria for the identification of suitable locations for wave energy conversion. Two zones within the study area emerge to be suitable for wave energy extraction. Swells from the southwest turned out to be the major source of wave energy and highest monthly median wave power reached about 33kW/m.

Penrose-like inequality with angular momentum for minimal surfaces

NASA Astrophysics Data System (ADS)

Anglada, Pablo

2018-02-01

In axially symmetric spacetimes the Penrose inequality can be strengthened to include angular momentum. We prove a version of this inequality for minimal surfaces, more precisely, a lower bound for the ADM mass in terms of the area of a minimal surface, the angular momentum and a particular measure of the surface size. We consider axially symmetric and asymptotically flat initial data, and use the monotonicity of the Geroch quasi-local energy on 2-surfaces along the inverse mean curvature flow.

Potential Energy Surface Database of Group II Dimer

National Institute of Standards and Technology Data Gateway

SRD 143 NIST Potential Energy Surface Database of Group II Dimer (Web, free access)   This database provides critical atomic and molecular data needed in order to evaluate the feasibility of using laser cooled and trapped Group II atomic species (Mg, Ca, Sr, and Ba) for ultra-precise optical clocks or quantum information processing devices.

S-Matrix to potential inversion of low-energy α-12C phase shifts

NASA Astrophysics Data System (ADS)

Cooper, S. G.; Mackintosh, R. S.

1990-10-01

The IP S-matrix to potential inversion procedure is applied to phase shifts for selected partial waves over a range of energies below the inelastic threshold for α-12C scattering. The phase shifts were determined by Plaga et al. Potentials found by Buck and Rubio to fit the low-energy alpha cluster resonances need only an increased attraction in the surface to accurately reproduce the phase-shift behaviour. Substantial differences between the potentials for odd and even partial waves are necessary. The surface tail of the potential is postulated to be a threshold effect.

Minimally conscious state or cortically mediated state?

PubMed

Naccache, Lionel

2018-04-01

Durable impairments of consciousness are currently classified in three main neurological categories: comatose state, vegetative state (also recently coined unresponsive wakefulness syndrome) and minimally conscious state. While the introduction of minimally conscious state, in 2002, was a major progress to help clinicians recognize complex non-reflexive behaviours in the absence of functional communication, it raises several problems. The most important issue related to minimally conscious state lies in its criteria: while behavioural definition of minimally conscious state lacks any direct evidence of patient's conscious content or conscious state, it includes the adjective 'conscious'. I discuss this major problem in this review and propose a novel interpretation of minimally conscious state: its criteria do not inform us about the potential residual consciousness of patients, but they do inform us with certainty about the presence of a cortically mediated state. Based on this constructive criticism review, I suggest three proposals aiming at improving the way we describe the subjective and cognitive state of non-communicating patients. In particular, I present a tentative new classification of impairments of consciousness that combines behavioural evidence with functional brain imaging data, in order to probe directly and univocally residual conscious processes.

Esophageal surgery in minimally invasive era

PubMed Central

Bencini, Lapo; Moraldi, Luca; Bartolini, Ilenia; Coratti, Andrea

2016-01-01

The widespread popularity of new surgical technologies such as laparoscopy, thoracoscopy and robotics has led many surgeons to treat esophageal diseases with these methods. The expected benefits of minimally invasive surgery (MIS) mainly include reductions of postoperative complications, length of hospital stay, and pain and better cosmetic results. All of these benefits could potentially be of great interest when dealing with the esophagus due to the potentially severe complications that can occur after conventional surgery. Moreover, robotic platforms are expected to reduce many of the difficulties encountered during advanced laparoscopic and thoracoscopic procedures such as anastomotic reconstructions, accurate lymphadenectomies, and vascular sutures. Almost all esophageal diseases are approachable in a minimally invasive way, including diverticula, gastro-esophageal reflux disease, achalasia, perforations and cancer. Nevertheless, while the limits of MIS for benign esophageal diseases are mainly technical issues and costs, oncologic outcomes remain the cornerstone of any procedure to cure malignancies, for which the long-term results are critical. Furthermore, many of the minimally invasive esophageal operations should be compared to pharmacologic interventions and advanced pure endoscopic procedures; such a comparison requires a difficult literature analysis and leads to some confounding results of clinical trials. This review aims to examine the evidence for the use of MIS in both malignancies and more common benign disease of the esophagus, with a particular emphasis on future developments and ongoing areas of research. PMID:26843913

Image denoising by a direct variational minimization

NASA Astrophysics Data System (ADS)

Janev, Marko; Atanacković, Teodor; Pilipović, Stevan; Obradović, Radovan

2011-12-01

In this article we introduce a novel method for the image de-noising which combines a mathematically well-posdenes of the variational modeling with the efficiency of a patch-based approach in the field of image processing. It based on a direct minimization of an energy functional containing a minimal surface regularizer that uses fractional gradient. The minimization is obtained on every predefined patch of the image, independently. By doing so, we avoid the use of an artificial time PDE model with its inherent problems of finding optimal stopping time, as well as the optimal time step. Moreover, we control the level of image smoothing on each patch (and thus on the whole image) by adapting the Lagrange multiplier using the information on the level of discontinuities on a particular patch, which we obtain by pre-processing. In order to reduce the average number of vectors in the approximation generator and still to obtain the minimal degradation, we combine a Ritz variational method for the actual minimization on a patch, and a complementary fractional variational principle. Thus, the proposed method becomes computationally feasible and applicable for practical purposes. We confirm our claims with experimental results, by comparing the proposed method with a couple of PDE-based methods, where we get significantly better denoising results specially on the oscillatory regions.

Potential energy landscape of TIP4P/2005 water

NASA Astrophysics Data System (ADS)

Handle, Philip H.; Sciortino, Francesco

2018-04-01

We report a numerical study of the statistical properties of the potential energy landscape of TIP4P/2005, one of the most accurate rigid water models. We show that, in the region where equilibrated configurations can be generated, a Gaussian landscape description is able to properly describe the model properties. We also find that the volume dependence of the landscape properties is consistent with the existence of a locus of density maxima in the phase diagram. The landscape-based equation of state accurately reproduces the TIP4P/2005 pressure-vs-volume curves, providing a sound extrapolation of the free-energy at low T. A positive-pressure liquid-liquid critical point is predicted by the resulting free-energy.

Computed Potential Energy Surfaces and Minimum Energy Pathway for Chemical Reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Langhoff, S. R. (Technical Monitor)

1994-01-01

Computed potential energy surfaces are often required for computation of such observables as rate constants as a function of temperature, product branching ratios, and other detailed properties. We have found that computation of the stationary points/reaction pathways using CASSCF/derivative methods, followed by use of the internally contracted CI method with the Dunning correlation consistent basis sets to obtain accurate energetics, gives useful results for a number of chemically important systems. Applications to complex reactions leading to NO and soot formation in hydrocarbon combustion are discussed.

A random-sampling high dimensional model representation neural network for building potential energy surfaces

NASA Astrophysics Data System (ADS)

Manzhos, Sergei; Carrington, Tucker

2006-08-01

We combine the high dimensional model representation (HDMR) idea of Rabitz and co-workers [J. Phys. Chem. 110, 2474 (2006)] with neural network (NN) fits to obtain an effective means of building multidimensional potentials. We verify that it is possible to determine an accurate many-dimensional potential by doing low dimensional fits. The final potential is a sum of terms each of which depends on a subset of the coordinates. This form facilitates quantum dynamics calculations. We use NNs to represent HDMR component functions that minimize error mode term by mode term. This NN procedure makes it possible to construct high-order component functions which in turn enable us to determine a good potential. It is shown that the number of available potential points determines the order of the HDMR which should be used.

A random-sampling high dimensional model representation neural network for building potential energy surfaces.

PubMed

Manzhos, Sergei; Carrington, Tucker

2006-08-28

We combine the high dimensional model representation (HDMR) idea of Rabitz and co-workers [J. Phys. Chem. 110, 2474 (2006)] with neural network (NN) fits to obtain an effective means of building multidimensional potentials. We verify that it is possible to determine an accurate many-dimensional potential by doing low dimensional fits. The final potential is a sum of terms each of which depends on a subset of the coordinates. This form facilitates quantum dynamics calculations. We use NNs to represent HDMR component functions that minimize error mode term by mode term. This NN procedure makes it possible to construct high-order component functions which in turn enable us to determine a good potential. It is shown that the number of available potential points determines the order of the HDMR which should be used.

Self-Averaging Property of Minimal Investment Risk of Mean-Variance Model.

PubMed

Shinzato, Takashi

2015-01-01

In portfolio optimization problems, the minimum expected investment risk is not always smaller than the expected minimal investment risk. That is, using a well-known approach from operations research, it is possible to derive a strategy that minimizes the expected investment risk, but this strategy does not always result in the best rate of return on assets. Prior to making investment decisions, it is important to an investor to know the potential minimal investment risk (or the expected minimal investment risk) and to determine the strategy that will maximize the return on assets. We use the self-averaging property to analyze the potential minimal investment risk and the concentrated investment level for the strategy that gives the best rate of return. We compare the results from our method with the results obtained by the operations research approach and with those obtained by a numerical simulation using the optimal portfolio. The results of our method and the numerical simulation are in agreement, but they differ from that of the operations research approach.

Self-Averaging Property of Minimal Investment Risk of Mean-Variance Model

PubMed Central

Shinzato, Takashi

2015-01-01

In portfolio optimization problems, the minimum expected investment risk is not always smaller than the expected minimal investment risk. That is, using a well-known approach from operations research, it is possible to derive a strategy that minimizes the expected investment risk, but this strategy does not always result in the best rate of return on assets. Prior to making investment decisions, it is important to an investor to know the potential minimal investment risk (or the expected minimal investment risk) and to determine the strategy that will maximize the return on assets. We use the self-averaging property to analyze the potential minimal investment risk and the concentrated investment level for the strategy that gives the best rate of return. We compare the results from our method with the results obtained by the operations research approach and with those obtained by a numerical simulation using the optimal portfolio. The results of our method and the numerical simulation are in agreement, but they differ from that of the operations research approach. PMID:26225761

Quantum Dynamics Study of the Potential Energy Minima Effect on Energy Efficiency for the F- + CH3Cl → FCH3 + Cl- Reaction.

PubMed

Li, Yida; Wang, Yuping; Wang, Dunyou

2017-04-13

The Polanyi rules on the energy efficiency on reactivity are summarized solely from the locations of barriers on the potential energy surfaces. Here, our quantum dynamics study for the F - + CH 3 Cl → FCH 3 + Cl - reaction shows that the two potential energy minima in the entrance channel on the potential energy surface play an essential role in energy efficiency on reactivity. The reactivity of this reaction is dominated by the low collision energies where two distinctive reaction mechanisms involve the two minima in the entrance channel. Overall, the Cl-CH 3 stretching motion and C-H 3 umbrella motion both are more efficient than the translational motion in promoting this reaction. Although this reaction has a negative energy barrier, our study shows that it is the minima in the entrance channel, together with the energy barrier relative to these minima, that determine the energy efficacy on reactivity.

Graph cuts via l1 norm minimization.

PubMed

Bhusnurmath, Arvind; Taylor, Camillo J

2008-10-01

Graph cuts have become an increasingly important tool for solving a number of energy minimization problems in computer vision and other fields. In this paper, the graph cut problem is reformulated as an unconstrained l1 norm minimization that can be solved effectively using interior point methods. This reformulation exposes connections between the graph cuts and other related continuous optimization problems. Eventually the problem is reduced to solving a sequence of sparse linear systems involving the Laplacian of the underlying graph. The proposed procedure exploits the structure of these linear systems in a manner that is easily amenable to parallel implementations. Experimental results obtained by applying the procedure to graphs derived from image processing problems are provided.

Networks of triboelectric nanogenerators for harvesting water wave energy: a potential approach toward blue energy.

PubMed

Chen, Jun; Yang, Jin; Li, Zhaoling; Fan, Xing; Zi, Yunlong; Jing, Qingshen; Guo, Hengyu; Wen, Zhen; Pradel, Ken C; Niu, Simiao; Wang, Zhong Lin

2015-03-24

With 70% of the earth's surface covered with water, wave energy is abundant and has the potential to be one of the most environmentally benign forms of electric energy. However, owing to lack of effective technology, water wave energy harvesting is almost unexplored as an energy source. Here, we report a network design made of triboelectric nanogenerators (TENGs) for large-scale harvesting of kinetic water energy. Relying on surface charging effect between the conventional polymers and very thin layer of metal as electrodes for each TENG, the TENG networks (TENG-NW) that naturally float on the water surface convert the slow, random, and high-force oscillatory wave energy into electricity. On the basis of the measured output of a single TENG, the TENG-NW is expected to give an average power output of 1.15 MW from 1 km(2) surface area. Given the compelling features, such as being lightweight, extremely cost-effective, environmentally friendly, easily implemented, and capable of floating on the water surface, the TENG-NW renders an innovative and effective approach toward large-scale blue energy harvesting from the ocean.

Development of a "First Principles" Water Potential with Flexible Monomers: Dimer Potential Energy Surface, VRT Spectrum, and Second Virial Coefficient.

PubMed

Babin, Volodymyr; Leforestier, Claude; Paesani, Francesco

2013-12-10

The development of a "first principles" water potential with flexible monomers (MB-pol) for molecular simulations of water systems from gas to condensed phases is described. MB-pol is built upon the many-body expansion of the intermolecular interactions, and the specific focus of this study is on the two-body term (V2B) representing the full-dimensional intermolecular part of the water dimer potential energy surface. V2B is constructed by fitting 40,000 dimer energies calculated at the CCSD(T)/CBS level of theory and imposing the correct asymptotic behavior at long-range as predicted from "first principles". The comparison of the calculated vibration-rotation tunneling (VRT) spectrum and second virial coefficient with the corresponding experimental results demonstrates the accuracy of the MB-pol dimer potential energy surface.

Validating a Coarse-Grained Potential Energy Function through Protein Loop Modelling

PubMed Central

MacDonald, James T.; Kelley, Lawrence A.; Freemont, Paul S.

2013-01-01

Coarse-grained (CG) methods for sampling protein conformational space have the potential to increase computational efficiency by reducing the degrees of freedom. The gain in computational efficiency of CG methods often comes at the expense of non-protein like local conformational features. This could cause problems when transitioning to full atom models in a hierarchical framework. Here, a CG potential energy function was validated by applying it to the problem of loop prediction. A novel method to sample the conformational space of backbone atoms was benchmarked using a standard test set consisting of 351 distinct loops. This method used a sequence-independent CG potential energy function representing the protein using -carbon positions only and sampling conformations with a Monte Carlo simulated annealing based protocol. Backbone atoms were added using a method previously described and then gradient minimised in the Rosetta force field. Despite the CG potential energy function being sequence-independent, the method performed similarly to methods that explicitly use either fragments of known protein backbones with similar sequences or residue-specific /-maps to restrict the search space. The method was also able to predict with sub-Angstrom accuracy two out of seven loops from recently solved crystal structures of proteins with low sequence and structure similarity to previously deposited structures in the PDB. The ability to sample realistic loop conformations directly from a potential energy function enables the incorporation of additional geometric restraints and the use of more advanced sampling methods in a way that is not possible to do easily with fragment replacement methods and also enable multi-scale simulations for protein design and protein structure prediction. These restraints could be derived from experimental data or could be design restraints in the case of computational protein design. C++ source code is available for download from http

New solution decomposition and minimization schemes for Poisson-Boltzmann equation in calculation of biomolecular electrostatics

NASA Astrophysics Data System (ADS)

Xie, Dexuan

2014-10-01

The Poisson-Boltzmann equation (PBE) is one widely-used implicit solvent continuum model in the calculation of electrostatic potential energy for biomolecules in ionic solvent, but its numerical solution remains a challenge due to its strong singularity and nonlinearity caused by its singular distribution source terms and exponential nonlinear terms. To effectively deal with such a challenge, in this paper, new solution decomposition and minimization schemes are proposed, together with a new PBE analysis on solution existence and uniqueness. Moreover, a PBE finite element program package is developed in Python based on the FEniCS program library and GAMer, a molecular surface and volumetric mesh generation program package. Numerical tests on proteins and a nonlinear Born ball model with an analytical solution validate the new solution decomposition and minimization schemes, and demonstrate the effectiveness and efficiency of the new PBE finite element program package.

Expansion Potentials for Exact Far-from-Equilibrium Spreading of Particles and Energy

DOE PAGES

Vasseur, Romain; Karrasch, Christoph; Moore, Joel E.

2015-12-01

We report that the rates at which energy and particle densities move to equalize arbitrarily large temperature and chemical potential differences in an isolated quantum system have an emergent thermodynamical description whenever energy or particle current commutes with the Hamiltonian. Concrete examples include the energy current in the 1D spinless fermion model with nearest-neighbor interactions (XXZ spin chain), energy current in Lorentz-invariant theories or particle current in interacting Bose gases in arbitrary dimension. Even far from equilibrium, these rates are controlled by state functions, which we call "expansion potentials", expressed as integrals of equilibrium Drude weights. This relation between nonequilibriummore » quantities and linear response implies non-equilibrium Maxwell relations for the Drude weights. Lastly, we verify our results via DMRG calculations for the XXZ chain.« less

Socio-economic and Engineering Assessments of Renewable Energy Cost Reduction Potential

NASA Astrophysics Data System (ADS)

Seel, Joachim

This dissertation combines three perspectives on the potential of cost reductions of renewable energy--a relevant topic, as high energy costs have traditionally been cited as major reason to vindicate developments of fossil fuel and nuclear power plants, and to justify financial support mechanisms and special incentives for renewable energy generators. First, I highlight the role of market and policy drivers in an international comparison of upfront capital expenses of residential photovoltaic systems in Germany and the United States that result in price differences of a factor of two and suggest cost reduction opportunities. In a second article I examine engineering approaches and siting considerations of large-scale photovoltaic projects in the United States that enable substantial system performance increases and allow thus for lower energy costs on a levelized basis. Finally, I investigate future cost reduction options of wind energy, ranging from capital expenses, operating expenses, and performance over a project's lifetime to financing costs. The assessment shows both substantial further cost decline potential for mature technologies like land-based turbines, nascent technologies like fixed-bottom offshore turbines, and experimental technologies like floating offshore turbines. The following paragraphs summarize each analysis: International upfront capital cost comparison of residential solar systems: Residential photovoltaic (PV) systems were twice as expensive in the United States as in Germany in 2012. This price discrepancy stems primarily from differences in non-hardware or "soft" costs between the two countries, of which only 35% be explained by differences in cumulative market size and associated learning. A survey of German PV installers was deployed to collect granular data on PV soft costs in Germany, and the results are compared to those of a similar survey of U.S. PV installers. Non-module hardware costs and all analyzed soft costs are lower in

Chemical energy storage: Part of a systemic solution

NASA Astrophysics Data System (ADS)

Schlögl, Robert

2017-07-01

This paper is a primer into concepts and opportunities of chemical energy storage. Starting from the quest for decarbonisation we reveal the possibilities of chemical energy storage. We briefly discuss the critical role of catalysis as enabling technology. We concentrate on options of large-scale production of chemicals from CO2 and green hydrogen. We discuss one potential application of fueling future combustion engines that could run with minimal regulated emissions without exhaust purifications and legal tricks.

Induced Seismicity Potential of Energy Technologies

NASA Astrophysics Data System (ADS)

Hitzman, Murray

2013-03-01

Earthquakes attributable to human activities-``induced seismic events''-have received heightened public attention in the United States over the past several years. Upon request from the U.S. Congress and the Department of Energy, the National Research Council was asked to assemble a committee of experts to examine the scale, scope, and consequences of seismicity induced during fluid injection and withdrawal associated with geothermal energy development, oil and gas development, and carbon capture and storage (CCS). The committee's report, publicly released in June 2012, indicates that induced seismicity associated with fluid injection or withdrawal is caused in most cases by change in pore fluid pressure and/or change in stress in the subsurface in the presence of faults with specific properties and orientations and a critical state of stress in the rocks. The factor that appears to have the most direct consequence in regard to induced seismicity is the net fluid balance (total balance of fluid introduced into or removed from the subsurface). Energy technology projects that are designed to maintain a balance between the amount of fluid being injected and withdrawn, such as most oil and gas development projects, appear to produce fewer seismic events than projects that do not maintain fluid balance. Major findings from the study include: (1) as presently implemented, the process of hydraulic fracturing for shale gas recovery does not pose a high risk for inducing felt seismic events; (2) injection for disposal of waste water derived from energy technologies does pose some risk for induced seismicity, but very few events have been documented over the past several decades relative to the large number of disposal wells in operation; and (3) CCS, due to the large net volumes of injected fluids suggested for future large-scale carbon storage projects, may have potential for inducing larger seismic events.

Collisions of excited Na atoms with H/sub 2/ molecules. I. Ab initio potential energy surfaces and qualitative discussion of the quenching process

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

Botschwina, P.; Meyer, W.; Hertel, I.V.

Potential energy surfaces have been calculated for the four lowest electronic states of Na (3 /sup 2/S, 3 /sup 2/P)+H/sub 2/(/sup 1/..sigma../sup +//sub g/) by means of the RHF--SCF and PNO--CEPA methods. For the so-called quenching process of Na (3 /sup 2/P) by H/sub 2/ at low initial translational energies (E--VRT energy transfer) the energetically most favorable path occurs in C/sub 2v/ symmetry, since: at intermediate Na--H/sub 2/ separation: the A /sup 2/B/sub 2/ potential energy surface is attractive. From the CEPA calculations, the crossing point of minimal energy between the X /sup 2/A/sub 1/ and A /sup 2/B/sub 2/more » surfaces is obtained at R/sub c/ = 3.57 a.u. and r/sub c/ = 2.17 a.u. with an energy difference to the asymptotic limit (R = infinity, r = r/sub e/) of -0.06 eV. It is thus classically accessible without any initial translational energy, but at low initial translational energies (approx.0.1 eV) quenching will be efficient only for arrangements of collision partners close to C/sub 2v/ symmetry. There is little indication of an avoiding crossing with an ionic intermediate correlating asymptotically with Na/sup +/ and H/sub 2//sup -/ as was assumed in previous discussions of the quenching process. The dependence of the total quenching cross sections on the initial translational energy is discussed by means of the ''absorbing sphere'' model, taking the initial zero-point vibrational energy of the hydrogen molecule into account. New experimental data of the product channel distribution in H/sub 2/ for center-of-mass forward scattering are presented. The final vibrational states v' = 3, 2, 1, and 0 of H/sub 2/ are populated to about 26%, 61%, 13%, and 0%, respectively. The observed distributions in H/sub 2/ (and D/sub 2/) may be rationalized by simple dynamic considerations on the basis of the calculated surfaces.« less

Minimizing liability during internal investigations.

PubMed

Morris, Cole

2010-01-01

Today's security professional must appreciate the potential landmines in any investigative effort and work collaboratively with others to minimize liability risks, the author points out. In this article he examines six civil torts that commonly arise from unprofessionally planned or poorly executed internal investigations-defamation, false imprisonment. intentional infliction of emotional distress, assault and battery, invasion of privacy, and malicious prosecution and abuse of process.

Detailed study of the water trimer potential energy surface

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

Fowler, J.E.; Schaefer, H.F. III

The potential energy surface of the water trimer has been studied through the use of ab initio quantum mechanical methods. Five stationary points were located, including one minimum and two transition states. All geometries were optimized at levels up to the double-[Zeta] plus polarization plus diffuse (DZP + diff) single and double excitation coupled cluster (CCSD) level of theory. CCSD single energy points were obtained for the minimum, two transition states, and the water monomer using the triple-[Zeta] plus double polarization plus diffuse (TZ2P + diff) basis at the geometries predicted by the DZP + diff CCSD method. Reported aremore » the following: geometrical parameters, total and relative energies, harmonic vibrational frequencies and infrared intensities for the minimum, and zero point vibrational energies for the minimum, two transition states, and three separated water molecules. 27 refs., 5 figs., 10 tabs.« less

Potential Impacts of Hydrokinetic and Wave Energy Conversion Technologies on Aquatic Environments

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

Čada, Glenn F.

2007-04-01

A new generation of hydropower technologies, the kinetic hydro and wave energy conversion devices, offers the possibility of generating electricity from the movements of water, without the need for dams and diversions. The Energy Policy Act of 2005 encouraged the development of these sources of renewable energy in the United States, and there is growing interest in deploying them globally. The technologies that would extract electricity from free-flowing streams, estuaries, and oceans have not been widely tested. Consequently, the U.S. Department of Energy convened a workshop to (1) identify the varieties of hydrokinetic energy and wave energy conversion devices andmore » their stages of development, (2) identify where these technologies can best operate, (3) identify the potential environmental issues associated with these technologies and possible mitigation measures, and (4) develop a list of research needs and/or practical solutions to address unresolved environmental issues. The article reviews the results of that workshop, focusing on potential effects on freshwater, estuarine, and marine ecosystems, and we describe recent national and international developments.« less

Assessment of Global Wind Energy Resource Utilization Potential

NASA Astrophysics Data System (ADS)

Ma, M.; He, B.; Guan, Y.; Zhang, H.; Song, S.

2017-09-01

Development of wind energy resource (WER) is a key to deal with climate change and energy structure adjustment. A crucial issue is to obtain the distribution and variability of WER, and mine the suitable location to exploit it. In this paper, a multicriteria evaluation (MCE) model is constructed by integrating resource richness and stability, utilization value and trend of resource, natural environment with weights. The global resource richness is assessed through wind power density (WPD) and multi-level wind speed. The utilizable value of resource is assessed by the frequency of effective wind. The resource stability is assessed by the coefficient of variation of WPD and the frequency of prevailing wind direction. Regression slope of long time series WPD is used to assess the trend of WER. All of the resource evaluation indicators are derived from the atmospheric reanalysis data ERA-Interim with spatial resolution 0.125°. The natural environment factors mainly refer to slope and land-use suitability, which are derived from multi-resolution terrain elevation data 2010 (GMTED 2010) and GlobalCover2009. Besides, the global WER utilization potential map is produced, which shows most high potential regions are located in north of Africa. Additionally, by verifying that 22.22 % and 48.8 9% operational wind farms fall on medium-high and high potential regions respectively, the result can provide a basis for the macroscopic siting of wind farm.

Towards ultra-thin plasmonic silicon wafer solar cells with minimized efficiency loss.

PubMed

Zhang, Yinan; Stokes, Nicholas; Jia, Baohua; Fan, Shanhui; Gu, Min

2014-05-13

The cost-effectiveness of market-dominating silicon wafer solar cells plays a key role in determining the competiveness of solar energy with other exhaustible energy sources. Reducing the silicon wafer thickness at a minimized efficiency loss represents a mainstream trend in increasing the cost-effectiveness of wafer-based solar cells. In this paper we demonstrate that, using the advanced light trapping strategy with a properly designed nanoparticle architecture, the wafer thickness can be dramatically reduced to only around 1/10 of the current thickness (180 μm) without any solar cell efficiency loss at 18.2%. Nanoparticle integrated ultra-thin solar cells with only 3% of the current wafer thickness can potentially achieve 15.3% efficiency combining the absorption enhancement with the benefit of thinner wafer induced open circuit voltage increase. This represents a 97% material saving with only 15% relative efficiency loss. These results demonstrate the feasibility and prospect of achieving high-efficiency ultra-thin silicon wafer cells with plasmonic light trapping.

Mass, charge, and energy separation by selective acceleration with a traveling potential hill

NASA Astrophysics Data System (ADS)

Tung, L. Schwager; Barr, W. L.; Lowder, R. S.; Post, R. F.

1996-10-01

A traveling electric potential hill has been used to generate an ion beam with an energy distribution that is mass dependent from a monoenergetic ion beam of mixed masses. This effect can be utilized as a novel method for mass separation applied to identification or enrichment of ions (e.g., of elements, isotopes, or molecules). This theory for mass-selective acceleration is presented here and is shown to be confirmed by experiment and by a time-dependent particle-in-cell computer simulation. Results show that monoenergetic ions with the particular mass of choice are accelerated by controlling the hill potential and the hill velocity. The hill velocity is typically 20%-30% faster than the ions to be accelerated. The ability of the hill to pickup a particular mass uses the fact that small kinetic energy differences in the lab frame appear much larger in the moving hill frame. Ions will gain energy from the approaching hill if their relative energy in the moving hill frame is less than the peak potential of the hill. The final energy of these accelerated ions can be several times the source energy, which facilitates energy filtering for mass purification or identification. If the hill potential is chosen to accelerate multiple masses, the heaviest mass will have the greatest final energy. Hence, choosing the appropriate hill potential and collector retarding voltage will isolate ions with the lightest, heaviest, or intermediate mass. In the experimental device, called a Solitron, purified 20Ne and 22Ne are extracted from a ribbon beam of neon that is originally composed of 20Ne:22Ne in the natural ratio of 91:9. The isotopic content of the processed beam is determined by measuring the energy distribution of the detected current. These results agree with the theory. In addition to mass selectivity, our theory can also be applied to the filtration of an ion beam according to charge state or energy. Because of this variety of properties, the Solitron is envisioned to

An Ab Initio Based Potential Energy Surface for Water

NASA Technical Reports Server (NTRS)

Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

1996-01-01

We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

Vegetative versus minimally conscious states: a study using TMS-EEG, sensory and event-related potentials.

PubMed

Ragazzoni, Aldo; Pirulli, Cornelia; Veniero, Domenica; Feurra, Matteo; Cincotta, Massimo; Giovannelli, Fabio; Chiaramonti, Roberta; Lino, Mario; Rossi, Simone; Miniussi, Carlo

2013-01-01

Differential diagnoses between vegetative and minimally conscious states (VS and MCS, respectively) are frequently incorrect. Hence, further research is necessary to improve the diagnostic accuracy at the bedside. The main neuropathological feature of VS is the diffuse damage of cortical and subcortical connections. Starting with this premise, we used electroencephalography (EEG) recordings to evaluate the cortical reactivity and effective connectivity during transcranial magnetic stimulation (TMS) in chronic VS or MCS patients. Moreover, the TMS-EEG data were compared with the results from standard somatosensory-evoked potentials (SEPs) and event-related potentials (ERPs). Thirteen patients with chronic consciousness disorders were examined at their bedsides. A group of healthy volunteers served as the control group. The amplitudes (reactivity) and scalp distributions (connectivity) of the cortical potentials evoked by TMS (TEPs) of the primary motor cortex were measured. Short-latency median nerve SEPs and auditory ERPs were also recorded. Reproducible TEPs were present in all control subjects in both the ipsilateral and the contralateral hemispheres relative to the site of the TMS. The amplitudes of the ipsilateral and contralateral TEPs were reduced in four of the five MCS patients, and the TEPs were bilaterally absent in one MCS patient. Among the VS patients, five did not manifest ipsilateral or contralateral TEPs, and three of the patients exhibited only ipsilateral TEPs with reduced amplitudes. The SEPs were altered in five VS and two MCS patients but did not correlate with the clinical diagnosis. The ERPs were impaired in all patients and did not correlate with the clinical diagnosis. These TEP results suggest that cortical reactivity and connectivity are severely impaired in all VS patients, whereas in most MCS patients, the TEPs are preserved but with abnormal features. Therefore, TEPs may add valuable information to the current clinical and

Vegetative versus Minimally Conscious States: A Study Using TMS-EEG, Sensory and Event-Related Potentials

PubMed Central

Ragazzoni, Aldo; Pirulli, Cornelia; Veniero, Domenica; Feurra, Matteo; Cincotta, Massimo; Giovannelli, Fabio; Chiaramonti, Roberta; Lino, Mario; Rossi, Simone; Miniussi, Carlo

2013-01-01

Differential diagnoses between vegetative and minimally conscious states (VS and MCS, respectively) are frequently incorrect. Hence, further research is necessary to improve the diagnostic accuracy at the bedside. The main neuropathological feature of VS is the diffuse damage of cortical and subcortical connections. Starting with this premise, we used electroencephalography (EEG) recordings to evaluate the cortical reactivity and effective connectivity during transcranial magnetic stimulation (TMS) in chronic VS or MCS patients. Moreover, the TMS-EEG data were compared with the results from standard somatosensory-evoked potentials (SEPs) and event-related potentials (ERPs). Thirteen patients with chronic consciousness disorders were examined at their bedsides. A group of healthy volunteers served as the control group. The amplitudes (reactivity) and scalp distributions (connectivity) of the cortical potentials evoked by TMS (TEPs) of the primary motor cortex were measured. Short-latency median nerve SEPs and auditory ERPs were also recorded. Reproducible TEPs were present in all control subjects in both the ipsilateral and the contralateral hemispheres relative to the site of the TMS. The amplitudes of the ipsilateral and contralateral TEPs were reduced in four of the five MCS patients, and the TEPs were bilaterally absent in one MCS patient. Among the VS patients, five did not manifest ipsilateral or contralateral TEPs, and three of the patients exhibited only ipsilateral TEPs with reduced amplitudes. The SEPs were altered in five VS and two MCS patients but did not correlate with the clinical diagnosis. The ERPs were impaired in all patients and did not correlate with the clinical diagnosis. These TEP results suggest that cortical reactivity and connectivity are severely impaired in all VS patients, whereas in most MCS patients, the TEPs are preserved but with abnormal features. Therefore, TEPs may add valuable information to the current clinical and

Supporting Current Energy Conversion Projects through Numerical Modeling

NASA Astrophysics Data System (ADS)

James, S. C.; Roberts, J.

2016-02-01

The primary goals of current energy conversion (CEC) technology being developed today are to optimize energy output and minimize environmental impact. CEC turbines generate energy from tidal and current systems and create wakes that interact with turbines located downstream of a device. The placement of devices can greatly influence power generation and structural reliability. CECs can also alter the environment surrounding the turbines, such as flow regimes, sediment dynamics, and water quality. These alterations pose potential stressors to numerous environmental receptors. Software is needed to investigate specific CEC sites to simulate power generation and hydrodynamic responses of a flow through a CEC turbine array so that these potential impacts can be evaluated. Moreover, this software can be used to optimize array layouts that yield the least changes to the environmental (i.e., hydrodynamics, sediment dynamics, and water quality). Through model calibration exercises, simulated wake profiles and turbulence intensities compare favorably to the experimental data and demonstrate the utility and accuracy of a fast-running tool for future siting and analysis of CEC arrays in complex domains. The Delft3D modeling tool facilitates siting of CEC projects through optimization of array layouts and evaluation of potential environmental effect all while provide a common "language" for academics, industry, and regulators to be able to discuss the implications of marine renewable energy projects. Given the enormity of any full-scale marine renewable energy project, it necessarily falls to modeling to evaluate how array operations must be addressed in an environmental impact statement in a way that engenders confidence in the assessment of the CEC array to minimize environmental effects.

Energy Savings Potential and RD&D Opportunities for Commercial Building HVAC Systems

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

Goetzler, William; Shandross, Richard; Young, Jim

The Building Technologies Office (BTO) commissioned this characterization and technology assessment of heating, ventilation, and air-conditioning (HVAC) systems for commercial buildings. The main objectives of this study: Identify a wide range of technology options in varying stages of development that could reduce commercial HVAC energy consumption; Characterize these technology options based on their technical energy-savings potential, development status, non-energy benefits, and other factors affecting end-user acceptance and the ability to compete with conventional HVAC technologies; Make specific recommendations to DOE and other stakeholders on potential research, development, and demonstration (RD&D) activities that would support further development of the most promisingmore » technology options.« less

Energy Expenditure during Physically Interactive Video Game Playing in Male College Students with Different Playing Experience

ERIC Educational Resources Information Center

Sell, Katie; Lillie, Tia; Taylor, Julie

2008-01-01

Objective: Researchers have yet to explore the effect of physically interactive video game playing on energy expenditure, despite its potential for meeting current minimal daily activity and energy expenditure recommendations. Participants and Methods: Nineteen male college students-12 experienced "Dance Dance Revolution" (DDR) players and 7…

Teaching Field Concept and Potential Energy at A-Level.

ERIC Educational Resources Information Center

Poon, C. H.

1986-01-01

Argues for a greater emphasis on the reality of fields in electronics and gravitation instruction. Advocates that the potential energy in a system be regarded as stored in the field rather than in the material bodies of the system. Provides a rationale and examples for this position. (ML)

Potential environmental effects of the leading edge hydrokinetic energy technology.

DOT National Transportation Integrated Search

2017-05-01

The Volpe Center evaluated potential environmental challenges and benefits of the ARPA-E funded research project, Marine Hydrokinetic Energy Harvesting Using Cyber-Physical Systems, led by Brown University. The Leading Edge research team develo...

Transportation Energy Futures Series. Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector

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

Vyas, A. D.; Patel, D. M.; Bertram, K. M.

2013-02-01

Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result ofmore » the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Transportation Energy Futures Series: Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector

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

Vyas, A. D.; Patel, D. M.; Bertram, K. M.

2013-03-01

Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result ofmore » the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.« less

Quantum models with energy-dependent potentials solvable in terms of exceptional orthogonal polynomials

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

Schulze-Halberg, Axel, E-mail: axgeschu@iun.edu; Department of Physics, Indiana University Northwest, 3400 Broadway, Gary IN 46408; Roy, Pinaki, E-mail: pinaki@isical.ac.in

We construct energy-dependent potentials for which the Schrödinger equations admit solutions in terms of exceptional orthogonal polynomials. Our method of construction is based on certain point transformations, applied to the equations of exceptional Hermite, Jacobi and Laguerre polynomials. We present several examples of boundary-value problems with energy-dependent potentials that admit a discrete spectrum and the corresponding normalizable solutions in closed form.

Estimating Renewable Energy Economic Potential in the United States. Methodology and Initial Results

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

Brown, Austin; Beiter, Philipp; Heimiller, Donna

This report describes a geospatial analysis method to estimate the economic potential of several renewable resources available for electricity generation in the United States. Economic potential, one measure of renewable generation potential, may be defined in several ways. For example, one definition might be expected revenues (based on local market prices) minus generation costs, considered over the expected lifetime of the generation asset. Another definition might be generation costs relative to a benchmark (e.g., a natural gas combined cycle plant) using assumptions of fuel prices, capital cost, and plant efficiency. Economic potential in this report is defined as the subsetmore » of the available resource technical potential where the cost required to generate the electricity (which determines the minimum revenue requirements for development of the resource) is below the revenue available in terms of displaced energy and displaced capacity. The assessment is conducted at a high geospatial resolution (more than 150,000 technology-specific sites in the continental United States) to capture the significant variation in local resource, costs, and revenue potential. This metric can be a useful screening factor for understanding the economic viability of renewable generation technologies at a specific location. In contrast to many common estimates of renewable energy potential, economic potential does not consider market dynamics, customer demand, or most policy drivers that may incent renewable energy generation.« less

Characterization of the potential energy landscape of an antiplasticized polymer.

PubMed

Riggleman, Robert A; Douglas, Jack F; de Pablo, Juan J

2007-07-01

The nature of the individual transitions on the potential energy landscape (PEL) associated with particle motion are directly examined for model fragile glass-forming polymer melts, and the results are compared to those of an antiplasticized polymer system. In previous work, we established that the addition of antiplasticizer reduces the fragility of glass formation so that the antiplasticized material is a stronger glass former. In the present work, we find that the antiplasticizing molecules reduce the energy barriers for relaxation compared to the pure polymer, implying that the antiplasticized system has smaller barriers to overcome in order to explore its configuration space. We examine the cooperativity of segmental motion in these bulk fluids and find that more extensive stringlike collective motion enables the system to overcome larger potential energy barriers, in qualitative agreement with both the Stillinger-Weber and Adam-Gibbs views of glass formation. Notably, the stringlike collective motion identified by our PEL analysis corresponds to incremental displacements that occur within larger-scale stringlike particle displacement processes associated with PEL metabasin transitions that mediate structural relaxation. These "substrings" nonetheless seem to exhibit changes in relative size with antiplasticization similar to those observed in "superstrings" that arise at elevated temperatures. We also study the effects of confinement on the energy barriers in each system. Film confinement makes the energy barriers substantially smaller in the pure polymer, while it has little effect on the energy barriers in the antiplasticized system. This observation is qualitatively consistent with our previous studies of stringlike motion in these fluids at higher temperatures and with recent experimental measurements by Torkelson and co-workers.

Computed potential energy surfaces for chemical reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.

1988-01-01

The minimum energy path for the addition of a hydrogen atom to N2 is characterized in CASSCF/CCI calculations using the (4s3p2d1f/3s2p1d) basis set, with additional single point calculations at the stationary points of the potential energy surface using the (5s4p3d2f/4s3p2d) basis set. These calculations represent the most extensive set of ab initio calculations completed to date, yielding a zero point corrected barrier for HN2 dissociation of approx. 8.5 kcal mol/1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional Transition State Theory and a method which utilizes an Eckart barrier to compute one dimensional quantum mechanical tunneling effects. It is concluded that the lifetime of the HN2 species is very short, greatly limiting its role in both termolecular recombination reactions and combustion processes.

Potential energy barriers to ion transport within lipid bilayers. Studies with tetraphenylborate.

PubMed Central

Andersen, P S; Fuchs, M

1975-01-01

Tetraphenylborate-induced current transients were studied in lipid bilayers formed from bacterial phosphatidylethanolamine in decane. This ion movement was essentially confined to the membrane in terior during the current transients. Charge movement through the interior of the membrane during the current transients was studied as a function of the applied potential. The transferred charge approached an upper limit with increasing potential, which is interpreted to be the amount of charge due to tetraphenylborate ions absorbed into the boundary regions of the bilayer. A further analysis of the charge transfer as a function of potential indicates that the movement of tetraphenylborate ions is only influenced by a certain farction of the applied potential. For bacterial phosphatidylethanolamine bilayers the effective potential is 77 +/- 4% of the applied potential. The initial conductance and the time constant of the current transients were studied as a function of the applied potential using a Nernst-Planck electrodiffusion regime. It was found that an image-force potential energy barrier gave a good prediction of the observed behavior, provided that the effective potential was used in the calculations. We could not get a satisfactory prediction of the observed behavior with an Eyring rate theory model or a trapezoidal potential energy barrier. PMID:1148364

Evaluation of Potential Locations for Siting Small Modular Reactors near Federal Energy Clusters to Support Federal Clean Energy Goals

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

Belles, Randy J.; Omitaomu, Olufemi A.

2014-09-01

Geographic information systems (GIS) technology was applied to analyze federal energy demand across the contiguous US. Several federal energy clusters were previously identified, including Hampton Roads, Virginia, which was subsequently studied in detail. This study provides an analysis of three additional diverse federal energy clusters. The analysis shows that there are potential sites in various federal energy clusters that could be evaluated further for placement of an integral pressurized-water reactor (iPWR) to support meeting federal clean energy goals.

Potential impacts of nanotechnology on energy transmission applications and needs.

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

Elcock, D.; Environmental Science Division

2007-11-30

The application of nanotechnologies to energy transmission has the potential to significantly impact both the deployed transmission technologies and the need for additional development. This could be a factor in assessing environmental impacts of right-of-way (ROW) development and use. For example, some nanotechnology applications may produce materials (e.g., cables) that are much stronger per unit volume than existing materials, enabling reduced footprints for construction and maintenance of electricity transmission lines. Other applications, such as more efficient lighting, lighter-weight materials for vehicle construction, and smaller batteries having greater storage capacities may reduce the need for long-distance transport of energy, and possiblymore » reduce the need for extensive future ROW development and many attendant environmental impacts. This report introduces the field of nanotechnology, describes some of the ways in which processes and products developed with or incorporating nanomaterials differ from traditional processes and products, and identifies some examples of how nanotechnology may be used to reduce potential ROW impacts. Potential environmental, safety, and health impacts are also discussed.« less

Potentials of storing solar energy in the form of hydrogen for Egypt

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

Abdel, A.A.L.; Mohamed, M.A.

1989-01-01

A seemingly insatiable demand for energy characterizes Egypt as it approaches the end of the twentieth century. With the limited energy resources in the country, R and D to utilize renewable sources of energy is a must. This paper examines first the energy situation in Egypt and explores the potential of using solar energy in hydrogen production from water. Different schemes of dissociating water are reviewed next. Finally, research findings are reported for some experimental runs carried out for the electrolysis of water by solar energy, utilizing an eight-water photovoltaic cell (Telephonken type) to generate the DC current.

Overcoming potential energy distortions in constrained internal coordinate molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Kandel, Saugat; Salomon-Ferrer, Romelia; Larsen, Adrien B.; Jain, Abhinandan; Vaidehi, Nagarajan

2016-01-01

The Internal Coordinate Molecular Dynamics (ICMD) method is an attractive molecular dynamics (MD) method for studying the dynamics of bonded systems such as proteins and polymers. It offers a simple venue for coarsening the dynamics model of a system at multiple hierarchical levels. For example, large scale protein dynamics can be studied using torsional dynamics, where large domains or helical structures can be treated as rigid bodies and the loops connecting them as flexible torsions. ICMD with such a dynamic model of the protein, combined with enhanced conformational sampling method such as temperature replica exchange, allows the sampling of large scale domain motion involving high energy barrier transitions. Once these large scale conformational transitions are sampled, all-torsion, or even all-atom, MD simulations can be carried out for the low energy conformations sampled via coarse grained ICMD to calculate the energetics of distinct conformations. Such hierarchical MD simulations can be carried out with standard all-atom forcefields without the need for compromising on the accuracy of the forces. Using constraints to treat bond lengths and bond angles as rigid can, however, distort the potential energy landscape of the system and reduce the number of dihedral transitions as well as conformational sampling. We present here a two-part solution to overcome such distortions of the potential energy landscape with ICMD models. To alleviate the intrinsic distortion that stems from the reduced phase space in torsional MD, we use the Fixman compensating potential. To additionally alleviate the extrinsic distortion that arises from the coupling between the dihedral angles and bond angles within a force field, we propose a hybrid ICMD method that allows the selective relaxing of bond angles. This hybrid ICMD method bridges the gap between all-atom MD and torsional MD. We demonstrate with examples that these methods together offer a solution to eliminate the potential

Overcoming potential energy distortions in constrained internal coordinate molecular dynamics simulations.

PubMed

Kandel, Saugat; Salomon-Ferrer, Romelia; Larsen, Adrien B; Jain, Abhinandan; Vaidehi, Nagarajan

2016-01-28

The Internal Coordinate Molecular Dynamics (ICMD) method is an attractive molecular dynamics (MD) method for studying the dynamics of bonded systems such as proteins and polymers. It offers a simple venue for coarsening the dynamics model of a system at multiple hierarchical levels. For example, large scale protein dynamics can be studied using torsional dynamics, where large domains or helical structures can be treated as rigid bodies and the loops connecting them as flexible torsions. ICMD with such a dynamic model of the protein, combined with enhanced conformational sampling method such as temperature replica exchange, allows the sampling of large scale domain motion involving high energy barrier transitions. Once these large scale conformational transitions are sampled, all-torsion, or even all-atom, MD simulations can be carried out for the low energy conformations sampled via coarse grained ICMD to calculate the energetics of distinct conformations. Such hierarchical MD simulations can be carried out with standard all-atom forcefields without the need for compromising on the accuracy of the forces. Using constraints to treat bond lengths and bond angles as rigid can, however, distort the potential energy landscape of the system and reduce the number of dihedral transitions as well as conformational sampling. We present here a two-part solution to overcome such distortions of the potential energy landscape with ICMD models. To alleviate the intrinsic distortion that stems from the reduced phase space in torsional MD, we use the Fixman compensating potential. To additionally alleviate the extrinsic distortion that arises from the coupling between the dihedral angles and bond angles within a force field, we propose a hybrid ICMD method that allows the selective relaxing of bond angles. This hybrid ICMD method bridges the gap between all-atom MD and torsional MD. We demonstrate with examples that these methods together offer a solution to eliminate the potential

Potential energy function for CH3+CH3 ⇆ C2H6: Attributes of the minimum energy path

NASA Astrophysics Data System (ADS)

Robertson, S. H.; Wardlaw, D. M.; Hirst, D. M.

1993-11-01

The region of the potential energy surface for the title reaction in the vicinity of its minimum energy path has been predicted from the analysis of ab initio electronic energy calculations. The ab initio procedure employs a 6-31G** basis set and a configuration interaction calculation which uses the orbitals obtained in a generalized valence bond calculation. Calculated equilibrium properties of ethane and of isolated methyl radical are compared to existing theoretical and experimental results. The reaction coordinate is represented by the carbon-carbon interatomic distance. The following attributes are reported as a function of this distance and fit to functional forms which smoothly interpolate between reactant and product values of each attribute: the minimum energy path potential, the minimum energy path geometry, normal mode frequencies for vibrational motion orthogonal to the reaction coordinate, a torsional potential, and a fundamental anharmonic frequency for local mode, out-of-plane CH3 bending (umbrella motion). The best representation is provided by a three-parameter modified Morse function for the minimum energy path potential and a two-parameter hyperbolic tangent switching function for all other attributes. A poorer but simpler representation, which may be satisfactory for selected applications, is provided by a standard Morse function and a one-parameter exponential switching function. Previous applications of the exponential switching function to estimate the reaction coordinate dependence of the frequencies and geometry of this system have assumed the same value of the range parameter α for each property and have taken α to be less than or equal to the ``standard'' value of 1.0 Å-1. Based on the present analysis this is incorrect: The α values depend on the property and range from ˜1.2 to ˜1.8 Å-1.

On a cost functional for H2/H(infinity) minimization

NASA Technical Reports Server (NTRS)

Macmartin, Douglas G.; Hall, Steven R.; Mustafa, Denis

1990-01-01

A cost functional is proposed and investigated which is motivated by minimizing the energy in a structure using only collocated feedback. Defined for an H(infinity)-norm bounded system, this cost functional also overbounds the H2 cost. Some properties of this cost functional are given, and preliminary results on the procedure for minimizing it are presented. The frequency domain cost functional is shown to have a time domain representation in terms of a Stackelberg non-zero sum differential game.

Vibration attenuation of rotating machines by application of magnetorheological dampers to minimize energy losses in the rotor support

NASA Astrophysics Data System (ADS)

Zapoměl, J.; Ferfecki, P.

2016-09-01

A frequently used technological solution for minimization of undesirable effects caused by vibration of rotating machines consists in placing damping devices in the rotor supports. The application of magnetorheological squeeze film dampers enables their optimum performance to be achieved in a wide range of rotating speeds by adapting their damping effect to the current operating conditions. The damping force, which is produced by squeezing the layer of magnetorheological oil, can be controlled by changing magnetic flux passing through the lubricant. The force acting between the rotor and its frame is transmitted through the rolling element bearing, the lubricating layer and the squirrel spring. The loading of the bearing produces a time variable friction moment, energy losses, uneven rotor running, and has an influence on the rotor service life and the current fluctuation in electric circuits. The carried out research consisted in the development of a mathematical model of a magnetorheological squeeze film damper, its implementation into the computational models of rotor systems, and in performing the study on the dependence of the energy losses and variation of the friction moment on the damping force and its control. The new and computationally stable mathematical model of a magnetorheological squeeze film damper, its implementation in the computational models of rigid rotors and learning more on the energy losses generated in the rotor supports in dependence on the damping effect are the principal contributions of this paper. The results of the computational simulations prove that a suitable control of the damping force enables the energy losses to be reduced in a wide velocity range.

Residential energy use in Mexico: Structure, evolution, environmental impacts, and savings potential

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

Masera, O.; Friedmann, R.; deBuen, O.

This article examines the characteristics of residential energy use in Mexico, its environmental impacts, and the savings potential of the major end-uses. The main options and barriers to increase the efficiency of energy use are discussed. The energy analysis is based on a disaggregation of residential energy use by end-uses. The dynamics of the evolution of the residential energy sector during the past 20 years are also addressed when the information is available. Major areas for research and for innovative decision-making are identified and prioritized.

Computed potential energy surfaces for chemical reactions

NASA Technical Reports Server (NTRS)

Walch, Stephen P.; Levin, Eugene

1993-01-01

A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

Observational constraints on tachyonic chameleon dark energy model

NASA Astrophysics Data System (ADS)

Banijamali, A.; Bellucci, S.; Fazlpour, B.; Solbi, M.

2018-03-01

It has been recently shown that tachyonic chameleon model of dark energy in which tachyon scalar field non-minimally coupled to the matter admits stable scaling attractor solution that could give rise to the late-time accelerated expansion of the universe and hence alleviate the coincidence problem. In the present work, we use data from Type Ia supernova (SN Ia) and Baryon Acoustic oscillations to place constraints on the model parameters. In our analysis we consider in general exponential and non-exponential forms for the non-minimal coupling function and tachyonic potential and show that the scenario is compatible with observations.

Identifying Potential Markets for Behind-the-Meter Battery Energy Storage:

Science.gov Websites

interval (usually 15 minutes) during a billing period. In many cases, these demand charges can account for therefore potential business cases for energy storage-were found in states not typically known for having

Assessment of wind energy potential in Poland

NASA Astrophysics Data System (ADS)

Starosta, Katarzyna; Linkowska, Joanna; Mazur, Andrzej

2014-05-01

The aim of the presentation is to show the suitability of using numerical model wind speed forecasts for the wind power industry applications in Poland. In accordance with the guidelines of the European Union, the consumption of wind energy in Poland is rapidly increasing. According to the report of Energy Regulatory Office from 30 March 2013, the installed capacity of wind power in Poland was 2807MW from 765 wind power stations. Wind energy is strongly dependent on the meteorological conditions. Based on the climatological wind speed data, potential energy zones within the area of Poland have been developed (H. Lorenc). They are the first criterion for assessing the location of the wind farm. However, for exact monitoring of a given wind farm location the prognostic data from numerical model forecasts are necessary. For the practical interpretation and further post-processing, the verification of the model data is very important. Polish Institute Meteorology and Water Management - National Research Institute (IMWM-NRI) runs an operational model COSMO (Consortium for Small-scale Modelling, version 4.8) using two nested domains at horizontal resolutions of 7 km and 2.8 km. The model produces 36 hour and 78 hour forecasts from 00 UTC, for 2.8 km and 7 km domain resolutions respectively. Numerical forecasts were compared with the observation of 60 SYNOP and 3 TEMP stations in Poland, using VERSUS2 (Unified System Verification Survey 2) and R package. For every zone the set of statistical indices (ME, MAE, RMSE) was calculated. Forecast errors for aerological profiles are shown for Polish TEMP stations at Wrocław, Legionowo and Łeba. The current studies are connected with a topic of the COST ES1002 WIRE-Weather Intelligence for Renewable Energies.

Wave Energy Prize - 1/50th Testing - Sea Potential

DOE Data Explorer

Wesley Scharmen

2015-12-04

This submission of data includes all the 1/50th scale testing data completed on the Wave Energy Prize for the Sea Potential team, and includes: 1/50th test data (raw & processed) 1/50th test data video and pictures 1/50th Test plans and testing documents SSTF_Submission (summarized results)

Rooftop Energy Potential of Low Income Communities in America REPLICA

DOE Data Explorer

Mooney, Meghan (ORCID:0000000309406958); Sigrin, Ben

1970-01-01

The Rooftop Energy Potential of Low Income Communities in America REPLICA data set provides estimates of residential rooftop solar technical potential at the tract-level with emphasis on estimates for Low and Moderate Income LMI populations. In addition to technical potential REPLICA is comprised of 10 additional datasets at the tract-level to provide socio-demographic and market context. The model year vintage of REPLICA is 2015. The LMI solar potential estimates are made at the tract level grouped by Area Median Income AMI income tenure and building type. These estimates are based off of LiDAR data of 128 metropolitan areas statistical modeling and ACS 2011-2015 demographic data. The remaining datasets are supplemental datasets that can be used in conjunction with the technical potential data for general LMI solar analysis planning and policy making. The core dataset is a wide-format CSV file seeds_ii_replica.csv that can be tagged to a tract geometry using the GEOID or GISJOIN fields. In addition users can download geographic shapefiles for the main or supplemental datasets. This dataset was generated as part of the larger NREL-led SEEDSII Solar Energy Evolution and Diffusion Studies project and specifically for the NREL technical report titled Rooftop Solar Technical Potential for Low-to-Moderate Income Households in the United States by Sigrin and Mooney 2018. This dataset is intended to give researchers planners advocates and policy-makers access to credible data to analyze low-income solar issues and potentially perform cost-benefit analysis for program design. To explore the data in an interactive web mapping environment use the NREL SolarForAll app.

Using benchmarking to minimize common DOE waste streams: Volume 5. Office paper waste

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

Levin, V.

Finding innovative ways to reduce waste streams generated at US Department of Energy (DOE) sites by 50% by the year 2000 is a challenge for DOE`s waste minimization efforts. A team composed of members from several DOE facilities used the quality tool known as benchmarking to improve waste minimization efforts. First the team examined office waste generation and handling processes at their sites. Then team members developed telephone and written questionnaires to help identify potential ``best-in-class`` industry partners willing to share information about their best waste minimization techniques and technologies. The team identified two benchmarking partners, NIKE, Inc., in Beaverton,more » Oregon, and Microsoft, Inc., in Redmond, Washington. Both companies have proactive, employee-driven environmental issues programs. Both companies report strong employee involvement, management commitment, and readily available markets for recyclable materials such as white paper and nonwhite assorted paper. The availability of markets, the initiative and cooperation of employees, and management support are the main enablers for their programs. At both companies, recycling and waste reduction programs often cut across traditional corporate divisions such as procurement, janitorial services, environmental compliance, grounds maintenance, cafeteria operations, surplus sales, and shipping and receiving. These companies exhibited good cooperation between these functions to design and implement recycling and waste reduction programs.« less

Automated Optimization of Potential Parameters

PubMed Central

Michele, Di Pierro; Ron, Elber

2013-01-01

An algorithm and software to refine parameters of empirical energy functions according to condensed phase experimental measurements are discussed. The algorithm is based on sensitivity analysis and local minimization of the differences between experiment and simulation as a function of potential parameters. It is illustrated for a toy problem of alanine dipeptide and is applied to folding of the peptide WAAAH. The helix fraction is highly sensitive to the potential parameters while the slope of the melting curve is not. The sensitivity variations make it difficult to satisfy both observations simultaneously. We conjecture that there is no set of parameters that reproduces experimental melting curves of short peptides that are modeled with the usual functional form of a force field. PMID:24015115

Augmented potential, energy densities, and virial relations in the weak- and strong-interaction limits of DFT

NASA Astrophysics Data System (ADS)

Vuckovic, Stefan; Levy, Mel; Gori-Giorgi, Paola

2017-12-01

The augmented potential introduced by Levy and Zahariev [Phys. Rev. Lett. 113, 113002 (2014)] is shifted with respect to the standard exchange-correlation potential of the Kohn-Sham density functional theory by a density-dependent constant that makes the total energy become equal to the sum of the occupied orbital energies. In this work, we analyze several features of this approach, focusing on the limit of infinite coupling strength and studying the shift and the corresponding energy density at different correlation regimes. We present and discuss coordinate scaling properties of the augmented potential, study its connection to the response potential, and use the shift to analyze the classical jellium and uniform gas models. We also study other definitions of the energy densities in relation to the functional construction by local interpolations along the adiabatic connection. Our findings indicate that the energy density that is defined in terms of the electrostatic potential of the exchange-correlation hole is particularly well suited for this purpose.

Minimally invasive technology in the management of breast disease.

PubMed

Hung, W K; Ying, M; Chan, C M; Lam, H S; Mak, K L

2009-01-01

Minimally invasive surgery is gaining popularity around the world because it achieves the same or even superior results when compared to standard surgery but with less morbidity. Minimally invasive breast surgery is a broad concept encompassing new developments in the field of breast surgery that work on this minimally invasive principle. In this regard, breast-conserving surgery and sentinel lymph node biopsy are good illustrations of this concept. There are three major areas of progress in the minimally invasive management of breast disease. First, percutaneous excisional devices are now available that can replace the surgical excision of breast mass lesions. Second, various ablative treatments are capable of destroying breast cancers in situ instead of surgical excision. Third, mammary ductoscopy provides a new approach to the investigation of mammary duct pathology. Clinical experience and potential applications of these new technologies are reviewed.

Minimal Information for Neural Electromagnetic Ontologies (MINEMO): A standards-compliant method for analysis and integration of event-related potentials (ERP) data

PubMed Central

Frishkoff, Gwen; Sydes, Jason; Mueller, Kurt; Frank, Robert; Curran, Tim; Connolly, John; Kilborn, Kerry; Molfese, Dennis; Perfetti, Charles; Malony, Allen

2011-01-01

We present MINEMO (Minimal Information for Neural ElectroMagnetic Ontologies), a checklist for the description of event-related potentials (ERP) studies. MINEMO extends MINI (Minimal Information for Neuroscience Investigations)to the ERP domain. Checklist terms are explicated in NEMO, a formal ontology that is designed to support ERP data sharing and integration. MINEMO is also linked to an ERP database and web application (the NEMO portal). Users upload their data and enter MINEMO information through the portal. The database then stores these entries in RDF (Resource Description Framework), along with summary metrics, i.e., spatial and temporal metadata. Together these spatial, temporal, and functional metadata provide a complete description of ERP data and the context in which these data were acquired. The RDF files then serve as inputs to ontology-based labeling and meta-analysis. Our ultimate goal is to represent ERPs using a rich semantic structure, so results can be queried at multiple levels, to stimulate novel hypotheses and to promote a high-level, integrative account of ERP results across diverse study methods and paradigms. PMID:22180824

Gene Architectures that Minimize Cost of Gene Expression.

PubMed

Frumkin, Idan; Schirman, Dvir; Rotman, Aviv; Li, Fangfei; Zahavi, Liron; Mordret, Ernest; Asraf, Omer; Wu, Song; Levy, Sasha F; Pilpel, Yitzhak

2017-01-05

Gene expression burdens cells by consuming resources and energy. While numerous studies have investigated regulation of expression level, little is known about gene design elements that govern expression costs. Here, we ask how cells minimize production costs while maintaining a given protein expression level and whether there are gene architectures that optimize this process. We measured fitness of ∼14,000 E. coli strains, each expressing a reporter gene with a unique 5' architecture. By comparing cost-effective and ineffective architectures, we found that cost per protein molecule could be minimized by lowering transcription levels, regulating translation speeds, and utilizing amino acids that are cheap to synthesize and that are less hydrophobic. We then examined natural E. coli genes and found that highly expressed genes have evolved more forcefully to minimize costs associated with their expression. Our study thus elucidates gene design elements that improve the economy of protein expression in natural and heterologous systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Unified Technical Concepts. Module 7: Potential and Kinetic Energy.

ERIC Educational Resources Information Center

Technical Education Research Center, Waco, TX.

This concept module on potential and kinetic energy is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each…

Modeling Molecular Interactions in Water: From Pairwise to Many-Body Potential Energy Functions

PubMed Central

2016-01-01

Almost 50 years have passed from the first computer simulations of water, and a large number of molecular models have been proposed since then to elucidate the unique behavior of water across different phases. In this article, we review the recent progress in the development of analytical potential energy functions that aim at correctly representing many-body effects. Starting from the many-body expansion of the interaction energy, specific focus is on different classes of potential energy functions built upon a hierarchy of approximations and on their ability to accurately reproduce reference data obtained from state-of-the-art electronic structure calculations and experimental measurements. We show that most recent potential energy functions, which include explicit short-range representations of two-body and three-body effects along with a physically correct description of many-body effects at all distances, predict the properties of water from the gas to the condensed phase with unprecedented accuracy, thus opening the door to the long-sought “universal model” capable of describing the behavior of water under different conditions and in different environments. PMID:27186804

A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation

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

Terry Battiest

2012-11-30

The project, A Feasibility Study to Evaluate Wind Energy Potential on the Navajo Nation, is funded under a solicitation issued by the U.S. Department of Energy Tribal Energy Program. Funding provided by the grant allowed the Navajo Nation to measure wind potential at two sites, one located within the boundaries of the Navajo Nation and the other off-reservation during the project period (September 5, 2005 - September 30, 2009). The recipient for the grant award is the Navajo Tribal Utility Authority (NTUA). The grant allowed the Navajo Nation and NTUA manage the wind feasibility from initial site selection through themore » decision-making process to commit to a site for wind generation development. The grant activities help to develop human capacity at NTUA and help NTUA to engage in renewable energy generation activities, including not only wind but also solar and biomass. The final report also includes information about development activities regarding the sited included in the grant-funded feasibility study.« less

Evaluation of global onshore wind energy potential and generation costs.

PubMed

Zhou, Yuyu; Luckow, Patrick; Smith, Steven J; Clarke, Leon

2012-07-17

In this study, we develop an updated global estimate of onshore wind energy potential using reanalysis wind speed data, along with updated wind turbine technology performance, land suitability factors, cost assumptions, and explicit consideration of transmission distance in the calculation of transmission costs. We find that wind has the potential to supply a significant portion of the world energy needs, although this potential varies substantially by region and with assumptions such as on what types of land can be used to site wind farms. Total global economic wind potential under central assumptions, that is, intermediate between optimistic and pessimistic, is estimated to be approximately 119.5 petawatt hours per year (13.6 TW) at less than 9 cents/kWh. A sensitivity analysis of eight key parameters is presented. Wind potential is sensitive to a number of input parameters, particularly wind speed (varying by -70% to +450% at less than 9 cents/kWh), land suitability (by -55% to +25%), turbine density (by -60% to +80%), and cost and financing options (by -20% to +200%), many of which have important policy implications. As a result of sensitivities studied here we suggest that further research intended to inform wind supply curve development focus not purely on physical science, such as better resolved wind maps, but also on these less well-defined factors, such as land-suitability, that will also have an impact on the long-term role of wind power.

Proposed minimal diagnostic criteria for myelodysplastic syndromes (MDS) and potential pre-MDS conditions

PubMed Central

Valent, Peter; Orazi, Attilio; Steensma, David P.; Ebert, Benjamin L.; Haase, Detlef; Malcovati, Luca; van de Loosdrecht, Arjan A.; Haferlach, Torsten; Westers, Theresia M.; Wells, Denise A.; Giagounidis, Aristoteles; Loken, Michael; Orfao, Alberto; Lübbert, Michael; Ganser, Arnold; Hofmann, Wolf-Karsten; Ogata, Kiyoyuki; Schanz, Julie; Béné, Marie C.; Hoermann, Gregor; Sperr, Wolfgang R.; Sotlar, Karl; Bettelheim, Peter; Stauder, Reinhard; Pfeilstöcker, Michael; Horny, Hans-Peter; Germing, Ulrich; Greenberg, Peter; Bennett, John M.

2017-01-01

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of myeloid neoplasms characterized by peripheral cytopenia, dysplasia, and a variable clinical course with about 30% risk to transform to secondary acute myeloid leukemia (AML). In the past 15 years, diagnostic evaluations, prognostication, and treatment of MDS have improved substantially. However, with the discovery of molecular markers and advent of novel targeted therapies, new challenges have emerged in the complex field of MDS. For example, MDS-related molecular lesions may be detectable in healthy individuals and increase in prevalence with age. Other patients exhibit persistent cytopenia of unknown etiology without dysplasia. Although these conditions are potential pre-phases of MDS they may also transform into other bone marrow neoplasms. Recently identified molecular, cytogenetic, and flow-based parameters may add in the delineation and prognostication of these conditions. However, no generally accepted integrated classification and no related criteria are as yet available. In an attempt to address this challenge, an international consensus group discussed these issues in a working conference in July 2016. The outcomes of this conference are summarized in the present article which includes criteria and a proposal for the classification of pre-MDS conditions as well as updated minimal diagnostic criteria of MDS. Moreover, we propose diagnostic standards to delineate between ´normal´, pre-MDS, and MDS. These standards and criteria should facilitate diagnostic and prognostic evaluations in clinical studies as well as in clinical practice. PMID:29088721

Task 2 Report - A GIS-Based Technical Potential Assessment of Domestic Energy Resources for Electricity Generation.

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

Lee, Nathan; Grue, Nicholas W; Rosenlieb, Evan

The purpose of this report is to support the Lao Ministry of Energy and Mines in assessing the technical potential of domestic energy resources for utility scale electricity generation in the Lao PDR. Specifically, this work provides assessments of technical potential, and associated maps of developable areas, for energy technologies of interest. This report details the methodology, assumptions, and datasets employed in this analysis to provide a transparent, replicable process for future analyses. The methodology and results presented are intended to be a fundamental input to subsequent decision making and energy planning-related analyses. This work concentrates on domestic energy resourcesmore » for utility-scale electricity generation and considers solar photovoltaic, wind, biomass, and coal resources. This work does not consider potentially imported energy resources (e.g., natural gas) or domestic energy resources that are not present in sufficient quantity for utility-scale generation (e.g., geothermal resources). A technical potential assessment of hydropower resources is currently not feasible due to the absence of required data including site-level assessments of multiple characteristics (e.g., geology environment and access) as well as spatial data on estimated non-exploited hydropower resources. This report is the second output of the Energy Alternatives Study for the Lao PDR, a collaboration led by the Lao Ministry of Energy and Mines and the United States Agency for International Development under the auspices of the Smart Infrastructure for the Mekong program. The Energy Alternatives Study is composed of five successive tasks that collectively support the project's goals. This work is focused on Task 2 - Assess technical potential of domestic energy resources for electricity generation. The work was carried out by a team from the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) in collaboration with the Lao Ministry of Energy

Onshore wind energy potential over Iberia: present and future projections

NASA Astrophysics Data System (ADS)

Rochinha, Carlos A.; Santos, João A.; Liberato, Margarida L. R.; Pinto, Joaquim G.

2014-05-01

Onshore grid-connected wind power generation has been explored for more than three decades in the Iberian Peninsula. Further, increasing attention has been devoted to renewable energy sources in a climate change context. While advantages of wind energy are widely recognized, its distribution is not spatially homogeneous and not uniform throughout the year. Hence, understanding these spatial-temporal distributions is critical in power system planning. The present study aims at assessing the potential power output estimated from 10 m wind components simulated by a regional climate model (CCLM), driven by ERA40 reanalysis. Datasets are available on a grid with a high spatial resolution (approximately 20 km) and over a 40-yr period (1961-2000). Furthermore, several target sites, located in areas with high installed wind generation capacity, are selected for local-to-regional scale assessments. The results show that potential wind power is higher over northern Iberia, mostly in Cantabria and Galicia, while Andalucía and Cataluña record the lowest values. With respect to the intra-annual variability, summer is by far the season with the lowest potential energy outputs. Furthermore, the inter-annual variability reveals an overall downward long-term trend over the 40-yr period, particularly in the winter time series. A CCLM transient experiment, forced by the SRES A1B emission scenario, is also discussed for a future period (2041-2070), after a model validation/calibration process (bias corrections). Significant changes in the wind power potential are projected for the future throughout Iberia, but their magnitude largely depends on the locations. This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER- 019524 (PTDC/AAC-CLI/121339/2010).

Energy deposition by heavy ions: Additivity of kinetic and potential energy contributions in hillock formation on CaF2

PubMed Central

Wang, Y. Y.; Grygiel, C.; Dufour, C.; Sun, J. R.; Wang, Z. G.; Zhao, Y. T.; Xiao, G. Q.; Cheng, R.; Zhou, X. M.; Ren, J. R.; Liu, S. D.; Lei, Y.; Sun, Y. B.; Ritter, R.; Gruber, E.; Cassimi, A.; Monnet, I.; Bouffard, S.; Aumayr, F.; Toulemonde, M.

2014-01-01

Modification of surface and bulk properties of solids by irradiation with ion beams is a widely used technique with many applications in material science. In this study, we show that nano-hillocks on CaF2 crystal surfaces can be formed by individual impact of medium energy (3 and 5 MeV) highly charged ions (Xe22+ to Xe30+) as well as swift (kinetic energies between 12 and 58 MeV) heavy xenon ions. For very slow highly charged ions the appearance of hillocks is known to be linked to a threshold in potential energy (Ep) while for swift heavy ions a minimum electronic energy loss per unit length (Se) is necessary. With our results we bridge the gap between these two extreme cases and demonstrate, that with increasing energy deposition via Se the Ep-threshold for hillock production can be lowered substantially. Surprisingly, both mechanisms of energy deposition in the target surface seem to contribute in an additive way, which can be visualized in a phase diagram. We show that the inelastic thermal spike model, originally developed to describe such material modifications for swift heavy ions, can be extended to the case where both kinetic and potential energies are deposited into the surface. PMID:25034006

Energy deposition by heavy ions: additivity of kinetic and potential energy contributions in hillock formation on CaF2.

PubMed

Wang, Y Y; Grygiel, C; Dufour, C; Sun, J R; Wang, Z G; Zhao, Y T; Xiao, G Q; Cheng, R; Zhou, X M; Ren, J R; Liu, S D; Lei, Y; Sun, Y B; Ritter, R; Gruber, E; Cassimi, A; Monnet, I; Bouffard, S; Aumayr, F; Toulemonde, M

2014-07-18

Modification of surface and bulk properties of solids by irradiation with ion beams is a widely used technique with many applications in material science. In this study, we show that nano-hillocks on CaF2 crystal surfaces can be formed by individual impact of medium energy (3 and 5 MeV) highly charged ions (Xe(22+) to Xe(30+)) as well as swift (kinetic energies between 12 and 58 MeV) heavy xenon ions. For very slow highly charged ions the appearance of hillocks is known to be linked to a threshold in potential energy (Ep) while for swift heavy ions a minimum electronic energy loss per unit length (Se) is necessary. With our results we bridge the gap between these two extreme cases and demonstrate, that with increasing energy deposition via Se the Ep-threshold for hillock production can be lowered substantially. Surprisingly, both mechanisms of energy deposition in the target surface seem to contribute in an additive way, which can be visualized in a phase diagram. We show that the inelastic thermal spike model, originally developed to describe such material modifications for swift heavy ions, can be extended to the case where both kinetic and potential energies are deposited into the surface.

Potential applications of low-energy shock waves in functional urology.

PubMed

Wang, Hung-Jen; Cheng, Jai-Hong; Chuang, Yao-Chi

2017-08-01

A shock wave, which carries energy and can propagate through a medium, is a type of continuous transmitted sonic wave with a frequency of 16 Hz-20 MHz. It is accompanied by processes involving rapid energy transformations. The energy associated with shock waves has been harnessed and used for various applications in medical science. High-energy extracorporeal shock wave therapy is the most successful application of shock waves, and has been used to disintegrate urolithiasis for 30 years. At lower energy levels, however, shock waves have enhanced expression of vascular endothelial growth factor, endothelial nitric oxide synthase, proliferating cell nuclear antigen, chemoattractant factors and recruitment of progenitor cells; shock waves have also improved tissue regeneration. Low-energy shock wave therapy has been used clinically with musculoskeletal disorders, ischemic cardiovascular disorders and erectile dysfunction, through the mechanisms of neovascularization, anti-inflammation and tissue regeneration. Furthermore, low-energy shock waves have been proposed to temporarily increase tissue permeability and facilitate intravesical drug delivery. The present review article provides information on the basics of shock wave physics, mechanisms of action on the biological system and potential applications in functional urology. © 2017 The Japanese Urological Association.

Ultrastrong steel via minimal lattice misfit and high-density nanoprecipitation

NASA Astrophysics Data System (ADS)