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Sample records for achieve maximum efficiency

  1. Optimal thickness of silicon membranes to achieve maximum thermoelectric efficiency: A first principles study

    NASA Astrophysics Data System (ADS)

    Mangold, Claudia; Neogi, Sanghamitra; Donadio, Davide

    2016-08-01

    Silicon nanostructures with reduced dimensionality, such as nanowires, membranes, and thin films, are promising thermoelectric materials, as they exhibit considerably reduced thermal conductivity. Here, we utilize density functional theory and Boltzmann transport equation to compute the electronic properties of ultra-thin crystalline silicon membranes with thickness between 1 and 12 nm. We predict that an optimal thickness of ˜7 nm maximizes the thermoelectric figure of merit of membranes with native oxide surface layers. Further thinning of the membranes, although attainable in experiments, reduces the electrical conductivity and worsens the thermoelectric efficiency.

  2. Maximum windmill efficiency

    SciTech Connect

    Greet, R.J.

    1980-09-01

    A result frequently quoted in engineering handbooks is that one-dimensional fluid flow theory places an upper limit on windmill efficiency at 16/27 or 59.3%. An error in the development invalidates this conclusion. One-dimensional flow analysis places no restrictions on realizable windmill output.

  3. Maximum efficiency of an autophase TWT

    NASA Astrophysics Data System (ADS)

    Bondarenko, B. N.; Dimashko, Iu. A.; Kryzhanovskii, V. G.

    1985-10-01

    Formulas are presented for the maximum efficiency of an autophase TWT. It is shown that the maximum efficiency is determined by the ohmic-loss coefficient and is achieved through a successive application of the isoadiabatic-amplification mode and the isoacceptance mode. The efficiency can reach a value of 75-80 percent; further increases may be achieved through an improvement of the capture quality.

  4. Maximum cooling and maximum efficiency of thermoacoustic refrigerators

    NASA Astrophysics Data System (ADS)

    Tartibu, L. K.

    2016-01-01

    This work provides valid experimental evidence on the difference between design for maximum cooling and maximum efficiency for thermoacoustic refrigerators. In addition, the influence of the geometry of the honeycomb ceramic stack on the performance of thermoacoustic refrigerators is presented as it affects the cooling power. Sixteen cordierite honeycomb ceramic stacks with square cross sections having four different lengths of 26, 48, 70 and 100 mm are considered. Measurements are taken at six different locations of the stack hot ends from the pressure antinode, namely 100, 200, 300, 400, 500 and 600 mm respectively. Measurement of temperature difference across the stack ends at steady state for different stack geometries are used to compute the cooling load and the coefficient of performance. The results obtained with atmospheric air showed that there is a distinct optimum depending on the design goal.

  5. On the efficiency at maximum cooling power

    NASA Astrophysics Data System (ADS)

    Apertet, Y.; Ouerdane, H.; Michot, A.; Goupil, C.; Lecoeur, Ph.

    2013-08-01

    The efficiency at maximum power (EMP) of heat engines operating as generators is one corner stone of finite-time thermodynamics, the Curzon-Ahlborn efficiency \\eta_CA being considered as a universal upper bound. Yet, no valid counterpart to \\eta_CA has been derived for the efficiency at maximum cooling power (EMCP) for heat engines operating as refrigerators. In this letter we analyse the reasons of the failure to obtain such a bound and we demonstrate that, despite the introduction of several optimisation criteria, the maximum cooling power condition should be considered as the genuine equivalent of maximum power condition in the finite-time thermodynamics frame. We then propose and discuss an analytic expression for the EMCP in the specific case of exoreversible refrigerators.

  6. Universality of efficiency at maximum power.

    PubMed

    Esposito, Massimiliano; Lindenberg, Katja; Van den Broeck, Christian

    2009-04-01

    We investigate the efficiency of power generation by thermochemical engines. For strong coupling between the particle and heat flows and in the presence of a left-right symmetry in the system, we demonstrate that the efficiency at maximum power displays universality up to quadratic order in the deviation from equilibrium. A maser model is presented to illustrate our argument.

  7. Achieving Maximum Power in Thermoelectric Generation with Simple Power Electronics

    NASA Astrophysics Data System (ADS)

    Youn, Nari; Lee, Hohyun; Wee, Daehyun; Gomez, Miguel; Reid, Rachel; Ohara, Brandon

    2014-06-01

    A thermoelectric generator typically delivers a relatively low power output, and hence it is of great practical importance to determine a design and operating condition close to those which can provide the maximum attainable power. To maintain a favorable condition for the maximum power output, power electronics circuits are usually applied. One of the simplest methods is to control the operating voltage at half the open-circuit voltage, assuming that the typical impedance-matching condition, in which the load and internal resistances are matched, yields the maximum power output. However, recent investigations have shown that, when external thermal resistances exist between the thermoelectric modules and thermal reservoirs, the impedance-matching condition is not identical to the condition for the maximum power output. In this article, it is argued that, although the impedance-matching condition is not the condition for maximum power output, the maximum power is still achievable when the operating voltage is kept at half the open-circuit voltage. More precisely, it is shown that the typical V- I curve for thermoelectric generators must show approximately linear behavior, which justifies the use of a simple strategy in thermoelectric power generation applications. The conditions for the validity of the approximation are mathematically discussed, supported by a few examples. Experimental evidence at room temperature is also provided.

  8. Maximum efficiency of the collisional Penrose process

    NASA Astrophysics Data System (ADS)

    Zaslavskii, O. B.

    2016-09-01

    We consider the collision of two particles that move in the equatorial plane near a general stationary rotating axially symmetric extremal black hole. One of the particles is critical (with fine-tuned parameters) and moves in the outward direction. The second particle (usual, not fine-tuned) comes from infinity. We examine the efficiency η of the collisional Penrose process. There are two relevant cases here: a particle falling into a black hole after collision (i) is heavy or (ii) has a finite mass. We show that the maximum of η in case (ii) is less than or equal to that in case (i). It is argued that for superheavy particles, the bound applies to nonequatorial motion as well. As an example, we analyze collision in the Kerr-Newman background. When the bound is the same for processes (i) and (ii), η =3 for this metric. For the Kerr black hole, recent results in the literature are reproduced.

  9. Maximum windmill efficiency in finite time

    NASA Astrophysics Data System (ADS)

    Huleihil, Mahmoud

    2009-05-01

    The fraction of the kinetic energy of the wind impinging on the rotor-swept area that a wind turbine can convert to useful power has been shown by Betz in an idealized laminar-flow model to have an upper limit of 16/27 or 59% approximately [I. H. Shames, Mechanics of Fluids, 2nd ed. (McGraw-Hill, New York, 1982), pp. A26-A31]. This figure is known as Betz number. Other studies [A. Rauh and W. Seelret, Appl. Energy 17, 15 (1984)] suggested that this figure should be considered as a guideline. In this paper, a new model is introduced and its efficiency at maximum power output is derived. The derived value is shown to be a function of the Betz number B and given by the formula ηmp=1-√1-B . This value is 36.2%, which agrees well with those of actually operating wind turbines. As a guideline, the wind turbine efficiency can be considered to be within the range of the two numbers of merit, the Betz number and ηmp.

  10. Condensing heat exchangers for maximum boiler efficiency

    SciTech Connect

    Johnson, D.W.; DiVitto, J.G.; Rakocy, M.E.

    1994-12-31

    Until now, boiler efficiency has been limited due to the minimum temperature allowed at the stack. Heat lost up the stack was in exchange for keeping the flue gas temperature above the water vapor dew point. If water vapor was allowed to condense out, rapid deterioration, due to acid corrosion, of the outlet duct and stack would result. With the development of the condensing heat exchanger, boiler efficiency can now exceed 90%. Approximately 1% gain in boiler efficiency can be expected for every 40 F (4.5 C) reduction in flue gas stack temperature. In the CHX{reg_sign} condensing heat exchanger, all gas wetted surfaces are covered with DuPont Teflon{reg_sign}. The Teflon covered heat exchanger surfaces are impervious to all acids normally resulting from the combustion of fossil fuels. This allows the flue gas to be cooled to below the water vapor dew point with no subsequent corrosion of the heat exchanger surfaces.

  11. The optimal polarizations for achieving maximum contrast in radar images

    NASA Technical Reports Server (NTRS)

    Swartz, A. A.; Yueh, H. A.; Kong, J. A.; Novak, L. M.; Shin, R. T.

    1988-01-01

    There is considerable interest in determining the optimal polarizations that maximize contrast between two scattering classes in polarimetric radar images. A systematic approach is presented for obtaining the optimal polarimetric matched filter, i.e., that filter which produces maximum contrast between two scattering classes. The maximization procedure involves solving an eigenvalue problem where the eigenvector corresponding to the maximum contrast ratio is an optimal polarimetric matched filter. To exhibit the physical significance of this filter, it is transformed into its associated transmitting and receiving polarization states, written in terms of horizontal and vertical vector components. For the special case where the transmitting polarization is fixed, the receiving polarization which maximizes the contrast ratio is also obtained. Polarimetric filtering is then applies to synthetic aperture radar images obtained from the Jet Propulsion Laboratory. It is shown, both numerically and through the use of radar imagery, that maximum image contrast can be realized when data is processed with the optimal polarimeter matched filter.

  12. Efficiency of autonomous soft nanomachines at maximum power.

    PubMed

    Seifert, Udo

    2011-01-14

    We consider nanosized artificial or biological machines working in steady state enforced by imposing nonequilibrium concentrations of solutes or by applying external forces, torques, or electric fields. For unicyclic and strongly coupled multicyclic machines, efficiency at maximum power is not bounded by the linear response value 1/2. For strong driving, it can even approach the thermodynamic limit 1. Quite generally, such machines fall into three different classes characterized, respectively, as "strong and efficient," "strong and inefficient," and "balanced." For weakly coupled multicyclic machines, efficiency at maximum power has lost any universality even in the linear response regime.

  13. Efficiency at maximum power of motor traffic on networks

    NASA Astrophysics Data System (ADS)

    Golubeva, N.; Imparato, A.

    2014-06-01

    We study motor traffic on Bethe networks subject to hard-core exclusion for both tightly coupled one-state machines and loosely coupled two-state machines that perform work against a constant load. In both cases we find an interaction-induced enhancement of the efficiency at maximum power (EMP) as compared to noninteracting motors. The EMP enhancement occurs for a wide range of network and single-motor parameters and is due to a change in the characteristic load-velocity relation caused by phase transitions in the system. Using a quantitative measure of the trade-off between the EMP enhancement and the corresponding loss in the maximum output power we identify parameter regimes where motor traffic systems operate efficiently at maximum power without a significant decrease in the maximum power output due to jamming effects.

  14. Achieving Maximum Power from Thermoelectric Generators with Maximum-Power-Point-Tracking Circuits Composed of a Boost-Cascaded-with-Buck Converter

    NASA Astrophysics Data System (ADS)

    Park, Hyunbin; Sim, Minseob; Kim, Shiho

    2015-06-01

    We propose a way of achieving maximum power and power-transfer efficiency from thermoelectric generators by optimized selection of maximum-power-point-tracking (MPPT) circuits composed of a boost-cascaded-with-buck converter. We investigated the effect of switch resistance on the MPPT performance of thermoelectric generators. The on-resistances of the switches affect the decrease in the conversion gain and reduce the maximum output power obtainable. Although the incremental values of the switch resistances are small, the resulting difference in the maximum duty ratio between the input and output powers is significant. For an MPPT controller composed of a boost converter with a practical nonideal switch, we need to monitor the output power instead of the input power to track the maximum power point of the thermoelectric generator. We provide a design strategy for MPPT controllers by considering the compromise in which a decrease in switch resistance causes an increase in the parasitic capacitance of the switch.

  15. The maximum efficiency of nano heat engines depends on more than temperature

    NASA Astrophysics Data System (ADS)

    Woods, Mischa; Ng, Nelly; Wehner, Stephanie

    Sadi Carnot's theorem regarding the maximum efficiency of heat engines is considered to be of fundamental importance in the theory of heat engines and thermodynamics. Here, we show that at the nano and quantum scale, this law needs to be revised in the sense that more information about the bath other than its temperature is required to decide whether maximum efficiency can be achieved. In particular, we derive new fundamental limitations of the efficiency of heat engines at the nano and quantum scale that show that the Carnot efficiency can only be achieved under special circumstances, and we derive a new maximum efficiency for others. A preprint can be found here arXiv:1506.02322 [quant-ph] Singapore's MOE Tier 3A Grant & STW, Netherlands.

  16. Achieving maximum plant yield in a weightless, bioregenerative system for a space craft.

    PubMed

    Salisbury, F B

    1984-01-01

    Limitations to maximum plant yield are photosynthesis, respiration, and harvest index (edible/total biomass). Our best results with wheat equal 97.5 g total biomass m-2 day-1. Theoretical maximums for our continuous 900 micromoles photons m-2 s-1 = 175 g carbohydrate, so our life-cycle efficiency is about 56%. Mineral nutrition has posed problems, but these are now nearly solved. CO2 levels are about 80 micromoles m-3 (1700 ppm; ambient = 330 ppm). We have grown wheat plants successfully under low-pressure sodium lamps. The main factor promising increased yields is canopy development. About half the life cycle is required to develop a canopy that uses light efficiently. At that point, we achieve 89% of maximum theoretical growth, suggesting that most parameters are nearly optimal. The next important frontier concerns application of these techniques to the microgravity environment of a space craft. There are engineering problems connected with circulation of nutrient solutions, for example. Plant responses to microgravity could decrease or increase yields. Leaves become epinastic, grass nodes elongate, and roots grow out of their medium. We are proposing space experiments to study these problems.

  17. Efficiency at maximum power of thermally coupled heat engines.

    PubMed

    Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

    2012-04-01

    We study the efficiency at maximum power of two coupled heat engines, using thermoelectric generators (TEGs) as engines. Assuming that the heat and electric charge fluxes in the TEGs are strongly coupled, we simulate numerically the dependence of the behavior of the global system on the electrical load resistance of each generator in order to obtain the working condition that permits maximization of the output power. It turns out that this condition is not unique. We derive a simple analytic expression giving the relation between the electrical load resistance of each generator permitting output power maximization. We then focus on the efficiency at maximum power (EMP) of the whole system to demonstrate that the Curzon-Ahlborn efficiency may not always be recovered: The EMP varies with the specific working conditions of each generator but remains in the range predicted by irreversible thermodynamics theory. We discuss our results in light of nonideal Carnot engine behavior.

  18. Efficiency at maximum power of thermally coupled heat engines.

    PubMed

    Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

    2012-04-01

    We study the efficiency at maximum power of two coupled heat engines, using thermoelectric generators (TEGs) as engines. Assuming that the heat and electric charge fluxes in the TEGs are strongly coupled, we simulate numerically the dependence of the behavior of the global system on the electrical load resistance of each generator in order to obtain the working condition that permits maximization of the output power. It turns out that this condition is not unique. We derive a simple analytic expression giving the relation between the electrical load resistance of each generator permitting output power maximization. We then focus on the efficiency at maximum power (EMP) of the whole system to demonstrate that the Curzon-Ahlborn efficiency may not always be recovered: The EMP varies with the specific working conditions of each generator but remains in the range predicted by irreversible thermodynamics theory. We discuss our results in light of nonideal Carnot engine behavior. PMID:22680454

  19. Efficiency at maximum power of low-dissipation Carnot engines.

    PubMed

    Esposito, Massimiliano; Kawai, Ryoichi; Lindenberg, Katja; Van den Broeck, Christian

    2010-10-01

    We study the efficiency at maximum power, η*, of engines performing finite-time Carnot cycles between a hot and a cold reservoir at temperatures Th and Tc, respectively. For engines reaching Carnot efficiency ηC=1-Tc/Th in the reversible limit (long cycle time, zero dissipation), we find in the limit of low dissipation that η* is bounded from above by ηC/(2-ηC) and from below by ηC/2. These bounds are reached when the ratio of the dissipation during the cold and hot isothermal phases tend, respectively, to zero or infinity. For symmetric dissipation (ratio one) the Curzon-Ahlborn efficiency ηCA=1-√Tc/Th] is recovered.

  20. Efficient maximum likelihood parameterization of continuous-time Markov processes

    PubMed Central

    McGibbon, Robert T.; Pande, Vijay S.

    2015-01-01

    Continuous-time Markov processes over finite state-spaces are widely used to model dynamical processes in many fields of natural and social science. Here, we introduce a maximum likelihood estimator for constructing such models from data observed at a finite time interval. This estimator is dramatically more efficient than prior approaches, enables the calculation of deterministic confidence intervals in all model parameters, and can easily enforce important physical constraints on the models such as detailed balance. We demonstrate and discuss the advantages of these models over existing discrete-time Markov models for the analysis of molecular dynamics simulations. PMID:26203016

  1. Efficiency at maximum power of a chemical engine.

    PubMed

    Hooyberghs, Hans; Cleuren, Bart; Salazar, Alberto; Indekeu, Joseph O; Van den Broeck, Christian

    2013-10-01

    A cyclically operating chemical engine is considered that converts chemical energy into mechanical work. The working fluid is a gas of finite-sized spherical particles interacting through elastic hard collisions. For a generic transport law for particle uptake and release, the efficiency at maximum power η(mp) [corrected] takes the form 1/2+cΔμ+O(Δμ(2)), with 1∕2 a universal constant and Δμ the chemical potential difference between the particle reservoirs. The linear coefficient c is zero for engines featuring a so-called left/right symmetry or particle fluxes that are antisymmetric in the applied chemical potential difference. Remarkably, the leading constant in η(mp) [corrected] is non-universal with respect to an exceptional modification of the transport law. For a nonlinear transport model, we obtain η(mp) = 1/(θ + 1) [corrected], with θ > 0 the power of Δμ in the transport equation.

  2. The consequence of maximum thermodynamic efficiency in Daisyworld.

    PubMed

    Pujol, Toni

    2002-07-01

    The imaginary planet of Daisyworld is the simplest model used to illustrate the implications of the Gaia hypothesis. The dynamics of daisies and their radiative interaction with the environment are described by fundamental equations of population ecology theory and physics. The parameterization of the turbulent energy flux between areas of different biological cover is similar to the diffusive-type approximation used in simple climate models. Here I show that the small variation of the planetary diffusivity adopted in the classical version of Daisyworld limits the range of values for the solar insolation for which biota may grow in the planet. Recent studies suggest that heat transport in a turbulent medium is constrained to maximize its efficiency. This condition is almost equivalent to maximizing the rate of entropy production due to non-radiative sources. Here, I apply the maximum entropy principle (MEP) to Daisyworld. I conclude that the MEP sets the maximum range of values for the solar insolation with a non-zero amount of daisies. Outside this range, daisies cannot grow in the planet for any physically realistic climate distribution. Inside this range, I assume a distribution of daisies in agreement with the MEP. The results substantially enlarge the range of climate stability, due to the biota, in comparison to the classical version of Daisyworld. A very stable temperature is found when two different species grow in the planet. PMID:12183130

  3. Achieving energy efficiency during collective communications

    SciTech Connect

    Sundriyal, Vaibhav; Sosonkina, Masha; Zhang, Zhao

    2012-09-13

    Energy consumption has become a major design constraint in modern computing systems. With the advent of petaflops architectures, power-efficient software stacks have become imperative for scalability. Techniques such as dynamic voltage and frequency scaling (called DVFS) and CPU clock modulation (called throttling) are often used to reduce the power consumption of the compute nodes. To avoid significant performance losses, these techniques should be used judiciously during parallel application execution. For example, its communication phases may be good candidates to apply the DVFS and CPU throttling without incurring a considerable performance loss. They are often considered as indivisible operations although little attention is being devoted to the energy saving potential of their algorithmic steps. In this work, two important collective communication operations, all-to-all and allgather, are investigated as to their augmentation with energy saving strategies on the per-call basis. The experiments prove the viability of such a fine-grain approach. They also validate a theoretical power consumption estimate for multicore nodes proposed here. While keeping the performance loss low, the obtained energy savings were always significantly higher than those achieved when DVFS or throttling were switched on across the entire application run

  4. Maximum efficiency of low-dissipation heat engines at arbitrary power

    NASA Astrophysics Data System (ADS)

    Holubec, Viktor; Ryabov, Artem

    2016-07-01

    We investigate maximum efficiency at a given power for low-dissipation heat engines. Close to maximum power, the maximum gain in efficiency scales as a square root of relative loss in power and this scaling is universal for a broad class of systems. For low-dissipation engines, we calculate the maximum gain in efficiency for an arbitrary fixed power. We show that engines working close to maximum power can operate at considerably larger efficiency compared to the efficiency at maximum power. Furthermore, we introduce universal bounds on maximum efficiency at a given power for low-dissipation heat engines. These bounds represent direct generalization of the bounds on efficiency at maximum power obtained by Esposito et al (2010 Phys. Rev. Lett. 105 150603). We derive the bounds analytically in the regime close to maximum power and for small power values. For the intermediate regime we present strong numerical evidence for the validity of the bounds.

  5. Netest: A Tool to Measure the Maximum Burst Size, Available Bandwidth and Achievable Throughput

    SciTech Connect

    Jin, Guojun; Tierney, Brian

    2003-01-31

    Distinguishing available bandwidth and achievable throughput is essential for improving network applications' performance. Achievable throughput is the throughput considering a number of factors such as network protocol, host speed, network path, and TCP buffer space, where as available bandwidth only considers the network path. Without understanding this difference, trying to improve network applications' performance is like ''blind men feeling the elephant'' [4]. In this paper, we define and distinguish bandwidth and throughput, and debate which part of each is achievable and which is available. Also, we introduce and discuss a new concept - Maximum Burst Size that is crucial to the network performance and bandwidth sharing. A tool, netest, is introduced to help users to determine the available bandwidth, and provides information to achieve better throughput with fairness of sharing the available bandwidth, thus reducing misuse of the network.

  6. Component Prioritization Schema for Achieving Maximum Time and Cost Benefits from Software Testing

    NASA Astrophysics Data System (ADS)

    Srivastava, Praveen Ranjan; Pareek, Deepak

    Software testing is any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results. Defining the end of software testing represents crucial features of any software development project. A premature release will involve risks like undetected bugs, cost of fixing faults later, and discontented customers. Any software organization would want to achieve maximum possible benefits from software testing with minimum resources. Testing time and cost need to be optimized for achieving a competitive edge in the market. In this paper, we propose a schema, called the Component Prioritization Schema (CPS), to achieve an effective and uniform prioritization of the software components. This schema serves as an extension to the Non Homogenous Poisson Process based Cumulative Priority Model. We also introduce an approach for handling time-intensive versus cost-intensive projects.

  7. Achieving Energy Efficiency Through Real-Time Feedback

    SciTech Connect

    Nesse, Ronald J.

    2011-09-01

    Through the careful implementation of simple behavior change measures, opportunities exist to achieve strategic gains, including greater operational efficiencies, energy cost savings, greater tenant health and ensuing productivity and an improved brand value through sustainability messaging and achievement.

  8. Using the network to achieve energy efficiency

    SciTech Connect

    Giglio, M.

    1995-12-01

    Novell, the third largest software company in the world, has developed Netware Embedded Systems Technology (NEST). NEST will take the network deeper into non-traditional computing environments and will imbed networking into more intelligent devices. Ultimately, this will lead to energy efficiencies in the office. NEST can make point-of-sale terminals, alarm systems, televisions, traffic controls, printers, lights, fax machines, copiers, HVAC controls, PBX machines, etc., either intelligent or more intelligent than they are currently. The mission statement for this particular group is to integrate over 30 million new intelligent devices into the workplace and the home with Novell networks by 1997. Computing trends have progressed from mainframes in the 1960s to keys, security systems, and airplanes in the year 2000. In fact, the new Boeing 777 has NEST in it, and it also has network servers on board. NEST enables the embedded network with the ability to put intelligence into devices. This gives one more control of the devices from wherever one is. For example, the pharmaceutical industry could use NEST to coordinate what the consumer is buying, what is in the warehouse, what the manufacturing plant is tooled for, and so on. Through NEST technology, the pharmaceutical industry now uses a camera that takes pictures of the pills. It can see whether an {open_quotes}overdose{close_quotes} or {open_quotes}underdose{close_quotes} of a particular type of pill is being manufactured. The plant can be shut down and corrections made immediately.

  9. Maximum-efficiency dc-motor project for electric vehicles

    NASA Astrophysics Data System (ADS)

    Wolfe, S.; Wellborn, J.

    1982-12-01

    Innovations to the operation of the typical direct current motor were made and included: an electronic circuit to generate a low level voltage circulation, an interface circuit capable of an 800% voltage amplification and aa 3000% current amplification, and a specially modified motor containing three additional brushes. The efficiency of the motor is maximized by an electronic circuit that artifically rotates the magnetic field around the armature at low RPM so that the motor is running at near peak efficiency virtually all the time.

  10. The ACT{sup 2} project: Demonstration of maximum energy efficiency in real buildings

    SciTech Connect

    Crawley, D.B.; Krieg, B.L.

    1991-11-01

    A large US utility recently began a project to determine whether the use of new energy-efficient end-use technologies and systems would economically achieve substantial energy savings (perhaps as high as 75% over current practice). Using a field-based demonstration approach, the Advanced Customer Technology Test (ACT{sup 2}) for Maximum Energy Efficiency is providing information on the maximum energy savings possible when integrated packages of new high-efficiency end-use technologies are incorporated into commercial and residential buildings and industrial and agricultural processes. This paper details the underlying rationale, approach, results to date, and future plans for ACT{sup 2}. The ultimate goal is energy efficiency (doing more with less energy) rather than energy conservation (freezing in the dark). In this paper, we first explain why a major United States utility is committed to pursuing demand-side management so aggressively. Next, we discuss the approach the utility chose for conducting the ACT{sup 2} project. We then review results obtained to date from the project`s pilot demonstration site. Last, we describe other related demonstration projects being proposed by the utility.

  11. The ACT sup 2 project: Demonstration of maximum energy efficiency in real buildings

    SciTech Connect

    Crawley, D.B. ); Krieg, B.L. )

    1991-11-01

    A large US utility recently began a project to determine whether the use of new energy-efficient end-use technologies and systems would economically achieve substantial energy savings (perhaps as high as 75% over current practice). Using a field-based demonstration approach, the Advanced Customer Technology Test (ACT{sup 2}) for Maximum Energy Efficiency is providing information on the maximum energy savings possible when integrated packages of new high-efficiency end-use technologies are incorporated into commercial and residential buildings and industrial and agricultural processes. This paper details the underlying rationale, approach, results to date, and future plans for ACT{sup 2}. The ultimate goal is energy efficiency (doing more with less energy) rather than energy conservation (freezing in the dark). In this paper, we first explain why a major United States utility is committed to pursuing demand-side management so aggressively. Next, we discuss the approach the utility chose for conducting the ACT{sup 2} project. We then review results obtained to date from the project's pilot demonstration site. Last, we describe other related demonstration projects being proposed by the utility.

  12. Continuity and boundary conditions in thermodynamics: From Carnot's efficiency to efficiencies at maximum power

    NASA Astrophysics Data System (ADS)

    Ouerdane, H.; Apertet, Y.; Goupil, C.; Lecoeur, Ph.

    2015-07-01

    Classical equilibrium thermodynamics is a theory of principles, which was built from empirical knowledge and debates on the nature and the use of heat as a means to produce motive power. By the beginning of the 20th century, the principles of thermodynamics were summarized into the so-called four laws, which were, as it turns out, definitive negative answers to the doomed quests for perpetual motion machines. As a matter of fact, one result of Sadi Carnot's work was precisely that the heat-to-work conversion process is fundamentally limited; as such, it is considered as a first version of the second law of thermodynamics. Although it was derived from Carnot's unrealistic model, the upper bound on the thermodynamic conversion efficiency, known as the Carnot efficiency, became a paradigm as the next target after the failure of the perpetual motion ideal. In the 1950's, Jacques Yvon published a conference paper containing the necessary ingredients for a new class of models, and even a formula, not so different from that of Carnot's efficiency, which later would become the new efficiency reference. Yvon's first analysis of a model of engine producing power, connected to heat source and sink through heat exchangers, went fairly unnoticed for twenty years, until Frank Curzon and Boye Ahlborn published their pedagogical paper about the effect of finite heat transfer on output power limitation and their derivation of the efficiency at maximum power, now mostly known as the Curzon-Ahlborn (CA) efficiency. The notion of finite rate explicitly introduced time in thermodynamics, and its significance cannot be overlooked as shown by the wealth of works devoted to what is now known as finite-time thermodynamics since the end of the 1970's. The favorable comparison of the CA efficiency to actual values led many to consider it as a universal upper bound for real heat engines, but things are not so straightforward that a simple formula may account for a variety of situations. The

  13. The equivalence of minimum entropy production and maximum thermal efficiency in endoreversible heat engines.

    PubMed

    Haseli, Y

    2016-05-01

    The objective of this study is to investigate the thermal efficiency and power production of typical models of endoreversible heat engines at the regime of minimum entropy generation rate. The study considers the Curzon-Ahlborn engine, the Novikov's engine, and the Carnot vapor cycle. The operational regimes at maximum thermal efficiency, maximum power output and minimum entropy production rate are compared for each of these engines. The results reveal that in an endoreversible heat engine, a reduction in entropy production corresponds to an increase in thermal efficiency. The three criteria of minimum entropy production, the maximum thermal efficiency, and the maximum power may become equivalent at the condition of fixed heat input.

  14. Convective gas flow development and the maximum depths achieved by helophyte vegetation in lakes

    PubMed Central

    Sorrell, Brian K.; Hawes, Ian

    2010-01-01

    Background and Aims Convective gas flow in helophytes (emergent aquatic plants) is thought to be an important adaptation for the ability to colonize deep water. In this study, the maximum depths achieved by seven helophytes were compared in 17 lakes differing in nutrient enrichment, light attenuation, shoreline exposure and sediment characteristics to establish the importance of convective flow for their ability to form the deepest helophyte vegetation in different environments. Methods Convective gas flow development was compared amongst the seven species, and species were allocated to ‘flow absent’, ‘low flow’ and ‘high flow’ categories. Regression tree analysis and quantile regression analysis were used to determine the roles of flow category, lake water quality, light attenuation and shoreline exposure on maximum helophyte depths. Key Results Two ‘flow absent’ species were restricted to very shallow water in all lakes and their depths were not affected by any environmental parameters. Three ‘low flow’ and two ‘high flow’ species had wide depth ranges, but ‘high flow’ species formed the deepest vegetation far more frequently than ‘low flow’ species. The ‘low flow’ species formed the deepest vegetation most commonly in oligotrophic lakes where oxygen demands in sediments were low, especially on exposed shorelines. The ‘high flow’ species were almost always those forming the deepest vegetation in eutrophic lakes, with Eleocharis sphacelata predominant when light attenuation was low, and Typha orientalis when light attenuation was high. Depths achieved by all five species with convective flow were limited by shoreline exposure, but T. orientalis was the least exposure-sensitive species. Conclusions Development of convective flow appears to be essential for dominance of helophyte species in >0·5 m depth, especially under eutrophic conditions. Exposure, sediment characteristics and light attenuation frequently constrain them

  15. Efficiency at maximum power and efficiency fluctuations in a linear Brownian heat-engine model.

    PubMed

    Park, Jong-Min; Chun, Hyun-Myung; Noh, Jae Dong

    2016-07-01

    We investigate the stochastic thermodynamics of a two-particle Langevin system. Each particle is in contact with a heat bath at different temperatures T_{1} and T_{2} (efficiency of the engine at maximum power η_{MP} is given by η_{MP}=1-sqrt[T_{2}/T_{1}]. This universal form has been known as a characteristic of endoreversible heat engines. Our result extends the universal behavior of η_{MP} to nonendoreversible engines. We also obtain the large deviation function of the probability distribution for the stochastic efficiency in the overdamped limit. The large deviation function takes the minimum value at macroscopic efficiency η=η[over ¯] and increases monotonically until it reaches plateaus when η≤η_{L} and η≥η_{R} with model-dependent parameters η_{R} and η_{L}. PMID:27575096

  16. Efficiency at maximum power and efficiency fluctuations in a linear Brownian heat-engine model

    NASA Astrophysics Data System (ADS)

    Park, Jong-Min; Chun, Hyun-Myung; Noh, Jae Dong

    2016-07-01

    We investigate the stochastic thermodynamics of a two-particle Langevin system. Each particle is in contact with a heat bath at different temperatures T1 and T2 (efficiency of the engine at maximum power ηM P is given by ηM P=1 -√{T2/T1 } . This universal form has been known as a characteristic of endoreversible heat engines. Our result extends the universal behavior of ηM P to nonendoreversible engines. We also obtain the large deviation function of the probability distribution for the stochastic efficiency in the overdamped limit. The large deviation function takes the minimum value at macroscopic efficiency η =η ¯ and increases monotonically until it reaches plateaus when η ≤ηL and η ≥ηR with model-dependent parameters ηR and ηL.

  17. Efficiency at maximum power and efficiency fluctuations in a linear Brownian heat-engine model.

    PubMed

    Park, Jong-Min; Chun, Hyun-Myung; Noh, Jae Dong

    2016-07-01

    We investigate the stochastic thermodynamics of a two-particle Langevin system. Each particle is in contact with a heat bath at different temperatures T_{1} and T_{2} (efficiency of the engine at maximum power η_{MP} is given by η_{MP}=1-sqrt[T_{2}/T_{1}]. This universal form has been known as a characteristic of endoreversible heat engines. Our result extends the universal behavior of η_{MP} to nonendoreversible engines. We also obtain the large deviation function of the probability distribution for the stochastic efficiency in the overdamped limit. The large deviation function takes the minimum value at macroscopic efficiency η=η[over ¯] and increases monotonically until it reaches plateaus when η≤η_{L} and η≥η_{R} with model-dependent parameters η_{R} and η_{L}.

  18. Maximum efficiency of ideal heat engines based on a small system: correction to the Carnot efficiency at the nanoscale.

    PubMed

    Quan, H T

    2014-06-01

    We study the maximum efficiency of a heat engine based on a small system. It is revealed that due to the finiteness of the system, irreversibility may arise when the working substance contacts with a heat reservoir. As a result, there is a working-substance-dependent correction to the Carnot efficiency. We derive a general and simple expression for the maximum efficiency of a Carnot cycle heat engine in terms of the relative entropy. This maximum efficiency approaches the Carnot efficiency asymptotically when the size of the working substance increases to the thermodynamic limit. Our study extends Carnot's result of the maximum efficiency to an arbitrary working substance and elucidates the subtlety of thermodynamic laws in small systems.

  19. Maximum efficiency of ideal heat engines based on a small system: correction to the Carnot efficiency at the nanoscale.

    PubMed

    Quan, H T

    2014-06-01

    We study the maximum efficiency of a heat engine based on a small system. It is revealed that due to the finiteness of the system, irreversibility may arise when the working substance contacts with a heat reservoir. As a result, there is a working-substance-dependent correction to the Carnot efficiency. We derive a general and simple expression for the maximum efficiency of a Carnot cycle heat engine in terms of the relative entropy. This maximum efficiency approaches the Carnot efficiency asymptotically when the size of the working substance increases to the thermodynamic limit. Our study extends Carnot's result of the maximum efficiency to an arbitrary working substance and elucidates the subtlety of thermodynamic laws in small systems. PMID:25019751

  20. Upside-Down Solar Cell Achieves Record Efficiencies (Fact Sheet)

    SciTech Connect

    Not Available

    2010-12-01

    The inverted metamorphic multijunction (IMM) solar cell is an exercise in efficient innovation - literally, as the technology boasted the highest demonstrated efficiency for converting sunlight into electrical energy at its debut in 2005. Scientists at the National Renewable Energy Laboratory (NREL) inverted the conventional photovoltaic (PV) structure to revolutionary effect, achieving solar conversion efficiencies of 33.8% and 40.8% under one-sun and concentrated conditions, respectively.

  1. Theoretical maximum efficiency of solar energy conversion in plasmonic metal-semiconductor heterojunctions.

    PubMed

    Cushing, Scott K; Bristow, Alan D; Wu, Nianqiang

    2015-11-28

    Plasmonics can enhance solar energy conversion in semiconductors by light trapping, hot electron transfer, and plasmon-induced resonance energy transfer (PIRET). The multifaceted response of the plasmon and multiple interaction pathways with the semiconductor makes optimization challenging, hindering design of efficient plasmonic architectures. Therefore, in this paper we use a density matrix model to capture the interplay between scattering, hot electrons, and dipole-dipole coupling through the plasmon's dephasing, including both the coherent and incoherent dynamics necessary for interactions on the plasmon's timescale. The model is extended to Shockley-Queisser limit calculations for both photovoltaics and solar-to-chemical conversion, revealing the optimal application of each enhancement mechanism based on plasmon energy, semiconductor energy, and plasmon dephasing. The results guide application of plasmonic solar-energy harvesting, showing which enhancement mechanism is most appropriate for a given semiconductor's weakness, and what nanostructures can achieve the maximum enhancement.

  2. Mind the bubbles: achieving stable measurements of maximum hydraulic conductivity through woody plant samples

    PubMed Central

    Espino, Susana; Schenk, H. Jochen

    2011-01-01

    The maximum specific hydraulic conductivity (kmax) of a plant sample is a measure of the ability of a plants’ vascular system to transport water and dissolved nutrients under optimum conditions. Precise measurements of kmax are needed in comparative studies of hydraulic conductivity, as well as for measuring the formation and repair of xylem embolisms. Unstable measurements of kmax are a common problem when measuring woody plant samples and it is commonly observed that kmax declines from initially high values, especially when positive water pressure is used to flush out embolisms. This study was designed to test five hypotheses that could potentially explain declines in kmax under positive pressure: (i) non-steady-state flow; (ii) swelling of pectin hydrogels in inter-vessel pit membranes; (iii) nucleation and coalescence of bubbles at constrictions in the xylem; (iv) physiological wounding responses; and (v) passive wounding responses, such as clogging of the xylem by debris. Prehydrated woody stems from Laurus nobilis (Lauraceae) and Encelia farinosa (Asteraceae) collected from plants grown in the Fullerton Arboretum in Southern California, were used to test these hypotheses using a xylem embolism meter (XYL'EM). Treatments included simultaneous measurements of stem inflow and outflow, enzyme inhibitors, stem-debarking, low water temperatures, different water degassing techniques, and varied concentrations of calcium, potassium, magnesium, and copper salts in aqueous measurement solutions. Stable measurements of kmax were observed at concentrations of calcium, potassium, and magnesium salts high enough to suppress bubble coalescence, as well as with deionized water that was degassed using a membrane contactor under strong vacuum. Bubble formation and coalescence under positive pressure in the xylem therefore appear to be the main cause for declining kmax values. Our findings suggest that degassing of water is essential for achieving stable and precise

  3. Mind the bubbles: achieving stable measurements of maximum hydraulic conductivity through woody plant samples.

    PubMed

    Espino, Susana; Schenk, H Jochen

    2011-01-01

    The maximum specific hydraulic conductivity (k(max)) of a plant sample is a measure of the ability of a plants' vascular system to transport water and dissolved nutrients under optimum conditions. Precise measurements of k(max) are needed in comparative studies of hydraulic conductivity, as well as for measuring the formation and repair of xylem embolisms. Unstable measurements of k(max) are a common problem when measuring woody plant samples and it is commonly observed that k(max) declines from initially high values, especially when positive water pressure is used to flush out embolisms. This study was designed to test five hypotheses that could potentially explain declines in k(max) under positive pressure: (i) non-steady-state flow; (ii) swelling of pectin hydrogels in inter-vessel pit membranes; (iii) nucleation and coalescence of bubbles at constrictions in the xylem; (iv) physiological wounding responses; and (v) passive wounding responses, such as clogging of the xylem by debris. Prehydrated woody stems from Laurus nobilis (Lauraceae) and Encelia farinosa (Asteraceae) collected from plants grown in the Fullerton Arboretum in Southern California, were used to test these hypotheses using a xylem embolism meter (XYL'EM). Treatments included simultaneous measurements of stem inflow and outflow, enzyme inhibitors, stem-debarking, low water temperatures, different water degassing techniques, and varied concentrations of calcium, potassium, magnesium, and copper salts in aqueous measurement solutions. Stable measurements of k(max) were observed at concentrations of calcium, potassium, and magnesium salts high enough to suppress bubble coalescence, as well as with deionized water that was degassed using a membrane contactor under strong vacuum. Bubble formation and coalescence under positive pressure in the xylem therefore appear to be the main cause for declining k(max) values. Our findings suggest that degassing of water is essential for achieving stable and

  4. Effect of Date and Location on Maximum Achievable Altitude for a Solar Powered Aircraft

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    1997-01-01

    The maximum altitude attainable for a solar powered aircraft without any energy storage capability is examined. Mission profiles for a solar powered aircraft were generated over a range of latitudes and dates. These profiles were used to determine which latitude-date combinations produced the highest achieavable altitude. Based on the presented analysis the results have shown that for a given time of year lower latitudes produced higher maximum altitudes. For all the cases examined the time and date which produced the highest altitude was around March at the equator.

  5. Influence of MoOx interlayer on the maximum achievable open-circuit voltage in organic photovoltaic cells

    NASA Astrophysics Data System (ADS)

    Zou, Yunlong; Holmes, Russell

    2013-03-01

    Transition metal oxides including molybdenum oxide (MoOx) are characterized by large work functions and deep energy levels relative to the organic semiconductors used in photovoltaic cells (OPVs). These materials have been used in OPVs as interlayers between the indium-tin-oxide anode and the active layers to increase the open-circuit voltage (VOC) and power conversion efficiency. We examine the role of MoOx in determining the maximum achievable VOC in planar heterojunction OPVs based on the donor-acceptor pairing of boron subphthalocyanine chloride (SubPc) and C60. While causing minor changes in VOC at room temperature, the inclusion of MoOx significantly changes the temperature dependence of VOC. Devices containing no interlayer show a maximum VOC\\ of 1.2 V, while devices containing MoOx show no saturation in VOC, reaching a value of >1.4 V at 110 K. We propose that the MoOx-SubPc interface forms a dissociating Schottky junction that provides an additional contribution to VOC at low temperature. Separate measurements of photoluminescence confirm that excitons in SubPc can be quenched by MoOx. Charge transfer at this interface is by hole extraction from SubPc to MoOx, and this mechanism favors donors with a deep highest occupied molecular orbital (HOMO) energy level. Consistent with this expectation, the temperature dependence of VOC for devices constructed using a donor with a shallower HOMO level, e.g. copper phthalocyanine, is independent of the presence of MoOx.

  6. Curating NASA's Future Extraterrestrial Sample Collections: How Do We Achieve Maximum Proficiency?

    NASA Technical Reports Server (NTRS)

    McCubbin, Francis; Evans, Cynthia; Zeigler, Ryan; Allton, Judith; Fries, Marc; Righter, Kevin; Zolensky, Michael

    2016-01-01

    The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with "The curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "... documentation, preservation, preparation, and distribution of samples for research, education, and public outreach." Here we describe some of the ongoing efforts to ensure that the future activities of the NASA Curation Office are working towards a state of maximum proficiency.

  7. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j) § 63.43... achieving such emission reduction and any non-air quality health and environmental impacts and energy..., and analysis of cost and non-air quality health environmental impacts or energy requirements for...

  8. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels.

    PubMed

    Singh, Meenesh R; Clark, Ezra L; Bell, Alexis T

    2015-11-10

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32-42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0-0.9 V, 0.9-1.95 V, and 1.95-3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices.

  9. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels

    PubMed Central

    Singh, Meenesh R.; Clark, Ezra L.; Bell, Alexis T.

    2015-01-01

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32–42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0–0.9 V, 0.9–1.95 V, and 1.95–3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices. PMID:26504215

  10. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels

    NASA Astrophysics Data System (ADS)

    Singh, Meenesh R.; Clark, Ezra L.; Bell, Alexis T.

    2015-11-01

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32-42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0-0.9 V, 0.9-1.95 V, and 1.95-3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices.

  11. Thermodynamic and achievable efficiencies for solar-driven electrochemical reduction of carbon dioxide to transportation fuels.

    PubMed

    Singh, Meenesh R; Clark, Ezra L; Bell, Alexis T

    2015-11-10

    Thermodynamic, achievable, and realistic efficiency limits of solar-driven electrochemical conversion of water and carbon dioxide to fuels are investigated as functions of light-absorber composition and configuration, and catalyst composition. The maximum thermodynamic efficiency at 1-sun illumination for adiabatic electrochemical synthesis of various solar fuels is in the range of 32-42%. Single-, double-, and triple-junction light absorbers are found to be optimal for electrochemical load ranges of 0-0.9 V, 0.9-1.95 V, and 1.95-3.5 V, respectively. Achievable solar-to-fuel (STF) efficiencies are determined using ideal double- and triple-junction light absorbers and the electrochemical load curves for CO2 reduction on silver and copper cathodes, and water oxidation kinetics over iridium oxide. The maximum achievable STF efficiencies for synthesis gas (H2 and CO) and Hythane (H2 and CH4) are 18.4% and 20.3%, respectively. Whereas the realistic STF efficiency of photoelectrochemical cells (PECs) can be as low as 0.8%, tandem PECs and photovoltaic (PV)-electrolyzers can operate at 7.2% under identical operating conditions. We show that the composition and energy content of solar fuels can also be adjusted by tuning the band-gaps of triple-junction light absorbers and/or the ratio of catalyst-to-PV area, and that the synthesis of liquid products and C2H4 have high profitability indices. PMID:26504215

  12. Slip resistance of winter footwear on snow and ice measured using maximum achievable incline.

    PubMed

    Hsu, Jennifer; Shaw, Robert; Novak, Alison; Li, Yue; Ormerod, Marcus; Newton, Rita; Dutta, Tilak; Fernie, Geoff

    2016-05-01

    Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear-surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance. Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established. PMID:26555738

  13. Slip resistance of winter footwear on snow and ice measured using maximum achievable incline.

    PubMed

    Hsu, Jennifer; Shaw, Robert; Novak, Alison; Li, Yue; Ormerod, Marcus; Newton, Rita; Dutta, Tilak; Fernie, Geoff

    2016-05-01

    Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear-surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance. Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established.

  14. Slip resistance of winter footwear on snow and ice measured using maximum achievable incline

    PubMed Central

    Hsu, Jennifer; Shaw, Robert; Novak, Alison; Li, Yue; Ormerod, Marcus; Newton, Rita; Dutta, Tilak; Fernie, Geoff

    2016-01-01

    Abstract Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear–surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance. Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established. PMID:26555738

  15. Maximum efficiency of state-space models of nanoscale energy conversion devices.

    PubMed

    Einax, Mario; Nitzan, Abraham

    2016-07-01

    The performance of nano-scale energy conversion devices is studied in the framework of state-space models where a device is described by a graph comprising states and transitions between them represented by nodes and links, respectively. Particular segments of this network represent input (driving) and output processes whose properly chosen flux ratio provides the energy conversion efficiency. Simple cyclical graphs yield Carnot efficiency for the maximum conversion yield. We give general proof that opening a link that separate between the two driving segments always leads to reduced efficiency. We illustrate these general result with simple models of a thermoelectric nanodevice and an organic photovoltaic cell. In the latter an intersecting link of the above type corresponds to non-radiative carriers recombination and the reduced maximum efficiency is manifested as a smaller open-circuit voltage. PMID:27394100

  16. Efficiency at maximum power output of quantum heat engines under finite-time operation.

    PubMed

    Wang, Jianhui; He, Jizhou; Wu, Zhaoqi

    2012-03-01

    We study the efficiency at maximum power, η(m), of irreversible quantum Carnot engines (QCEs) that perform finite-time cycles between a hot and a cold reservoir at temperatures T(h) and T(c), respectively. For QCEs in the reversible limit (long cycle period, zero dissipation), η(m) becomes identical to the Carnot efficiency η(C)=1-T(c)/T(h). For QCE cycles in which nonadiabatic dissipation and the time spent on two adiabats are included, the efficiency η(m) at maximum power output is bounded from above by η(C)/(2-η(C)) and from below by η(C)/2. In the case of symmetric dissipation, the Curzon-Ahlborn efficiency η(CA)=1-√(T(c)/T(h)) is recovered under the condition that the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation.

  17. Maximum efficiency of state-space models of nanoscale energy conversion devices.

    PubMed

    Einax, Mario; Nitzan, Abraham

    2016-07-01

    The performance of nano-scale energy conversion devices is studied in the framework of state-space models where a device is described by a graph comprising states and transitions between them represented by nodes and links, respectively. Particular segments of this network represent input (driving) and output processes whose properly chosen flux ratio provides the energy conversion efficiency. Simple cyclical graphs yield Carnot efficiency for the maximum conversion yield. We give general proof that opening a link that separate between the two driving segments always leads to reduced efficiency. We illustrate these general result with simple models of a thermoelectric nanodevice and an organic photovoltaic cell. In the latter an intersecting link of the above type corresponds to non-radiative carriers recombination and the reduced maximum efficiency is manifested as a smaller open-circuit voltage.

  18. Maximum efficiency of state-space models of nanoscale energy conversion devices

    NASA Astrophysics Data System (ADS)

    Einax, Mario; Nitzan, Abraham

    2016-07-01

    The performance of nano-scale energy conversion devices is studied in the framework of state-space models where a device is described by a graph comprising states and transitions between them represented by nodes and links, respectively. Particular segments of this network represent input (driving) and output processes whose properly chosen flux ratio provides the energy conversion efficiency. Simple cyclical graphs yield Carnot efficiency for the maximum conversion yield. We give general proof that opening a link that separate between the two driving segments always leads to reduced efficiency. We illustrate these general result with simple models of a thermoelectric nanodevice and an organic photovoltaic cell. In the latter an intersecting link of the above type corresponds to non-radiative carriers recombination and the reduced maximum efficiency is manifested as a smaller open-circuit voltage.

  19. The efficient algorithms for achieving Euclidean distance transformation.

    PubMed

    Shih, Frank Y; Wu, Yi-Ta

    2004-08-01

    Euclidean distance transformation (EDT) is used to convert a digital binary image consisting of object (foreground) and nonobject (background) pixels into another image where each pixel has a value of the minimum Euclidean distance from nonobject pixels. In this paper, the improved iterative erosion algorithm is proposed to avoid the redundant calculations in the iterative erosion algorithm. Furthermore, to avoid the iterative operations, the two-scan-based algorithm by a deriving approach is developed for achieving EDT correctly and efficiently in a constant time. Besides, we discover when obstacles appear in the image, many algorithms cannot achieve the correct EDT except our two-scan-based algorithm. Moreover, the two-scan-based algorithm does not require the additional cost of preprocessing or relative-coordinates recording.

  20. Maximum photosynthetic efficiency of biomass growth: a criticism of some measurements

    SciTech Connect

    Lee, Y.K.; Pirt, S.J.

    1982-02-01

    The yield of biomass produced in a photosynthetic culture is an expression of the photosynthetic efficiency. Microbial cells consume energy for both growth and for maintenance. The bioenergetics of Chlorella cultures and the maximum growth yields obtained by various researchers are examined in this paper.

  1. Bias and Efficiency in Structural Equation Modeling: Maximum Likelihood versus Robust Methods

    ERIC Educational Resources Information Center

    Zhong, Xiaoling; Yuan, Ke-Hai

    2011-01-01

    In the structural equation modeling literature, the normal-distribution-based maximum likelihood (ML) method is most widely used, partly because the resulting estimator is claimed to be asymptotically unbiased and most efficient. However, this may not hold when data deviate from normal distribution. Outlying cases or nonnormally distributed data,…

  2. A more efficient formulation for computation of the maximum loading points in electric power systems

    SciTech Connect

    Chiang, H.D.; Jean-Jumeau, R.

    1995-05-01

    This paper presents a more efficient formulation for computation of the maximum loading points. A distinguishing feature of the new formulation is that it is of dimension (n + 1), instead of the existing formulation of dimension (2n + 1), for n-dimensional load flow equations. This feature makes computation of the maximum loading points very inexpensive in comparison with those required in the existing formulation. A theoretical basis for the new formulation is provided. The new problem formulation is derived by using a simple reparameterization scheme and exploiting the special properties of the power flow model. Moreover, the proposed test function is shown to be monotonic in the vicinity of a maximum loading point. Therefore, it allows one to monitor the approach to maximum loading points during the solution search process. Simulation results on a 234-bus system are presented.

  3. Some methods for achieving more efficient performance of fuel assemblies

    NASA Astrophysics Data System (ADS)

    Boltenko, E. A.

    2014-07-01

    More efficient operation of reactor plant fuel assemblies can be achieved through the use of new technical solutions aimed at obtaining more uniform distribution of coolant over the fuel assembly section, more intense heat removal on convex heat-transfer surfaces, and higher values of departure from nucleate boiling ratio (DNBR). Technical solutions using which it is possible to obtain more intense heat removal on convex heat-transfer surfaces and higher DNBR values in reactor plant fuel assemblies are considered. An alternative heat removal arrangement is described using which it is possible to obtain a significantly higher power density in a reactor plant and essentially lower maximal fuel rod temperature.

  4. Curating NASA's future extraterrestrial sample collections: How do we achieve maximum proficiency?

    NASA Astrophysics Data System (ADS)

    McCubbin, Francis; Evans, Cynthia; Allton, Judith; Fries, Marc; Righter, Kevin; Zolensky, Michael; Zeigler, Ryan

    2016-07-01

    Introduction: The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with "The curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "…documentation, preservation, preparation, and distribution of samples for research, education, and public outreach." Here we describe some of the ongoing efforts to ensure that the future activities of the NASA Curation Office are working to-wards a state of maximum proficiency. Founding Principle: Curatorial activities began at JSC (Manned Spacecraft Center before 1973) as soon as design and construction planning for the Lunar Receiving Laboratory (LRL) began in 1964 [1], not with the return of the Apollo samples in 1969, nor with the completion of the LRL in 1967. This practice has since proven that curation begins as soon as a sample return mission is conceived, and this founding principle continues to return dividends today [e.g., 2]. The Next Decade: Part of the curation process is planning for the future, and we refer to these planning efforts as "advanced curation" [3]. Advanced Curation is tasked with developing procedures, technology, and data sets necessary for curating new types of collections as envisioned by NASA exploration goals. We are (and have been) planning for future curation, including cold curation, extended curation of ices and volatiles, curation of samples with special chemical considerations such as perchlorate-rich samples, curation of organically- and biologically-sensitive samples, and the use of minimally invasive analytical techniques (e.g., micro-CT, [4]) to characterize samples. These efforts will be useful for Mars Sample Return

  5. Efficiency at and near maximum power of low-dissipation heat engines.

    PubMed

    Holubec, Viktor; Ryabov, Artem

    2015-11-01

    A universality in optimization of trade-off between power and efficiency for low-dissipation Carnot cycles is presented. It is shown that any trade-off measure expressible in terms of efficiency and the ratio of power to its maximum value can be optimized independently of most details of the dynamics and of the coupling to thermal reservoirs. The result is demonstrated on two specific trade-off measures. The first one is designed for finding optimal efficiency for a given output power and clearly reveals diseconomy of engines working at maximum power. As the second example we derive universal lower and upper bounds on the efficiency at maximum trade-off given by the product of power and efficiency. The results are illustrated on a model of a diffusion-based heat engine. Such engines operate in the low-dissipation regime given that the used driving minimizes the work dissipated during the isothermal branches. The peculiarities of the corresponding optimization procedure are reviewed and thoroughly discussed. PMID:26651665

  6. Efficiency at and near maximum power of low-dissipation heat engines.

    PubMed

    Holubec, Viktor; Ryabov, Artem

    2015-11-01

    A universality in optimization of trade-off between power and efficiency for low-dissipation Carnot cycles is presented. It is shown that any trade-off measure expressible in terms of efficiency and the ratio of power to its maximum value can be optimized independently of most details of the dynamics and of the coupling to thermal reservoirs. The result is demonstrated on two specific trade-off measures. The first one is designed for finding optimal efficiency for a given output power and clearly reveals diseconomy of engines working at maximum power. As the second example we derive universal lower and upper bounds on the efficiency at maximum trade-off given by the product of power and efficiency. The results are illustrated on a model of a diffusion-based heat engine. Such engines operate in the low-dissipation regime given that the used driving minimizes the work dissipated during the isothermal branches. The peculiarities of the corresponding optimization procedure are reviewed and thoroughly discussed.

  7. Efficiency at and near maximum power of low-dissipation heat engines

    NASA Astrophysics Data System (ADS)

    Holubec, Viktor; Ryabov, Artem

    2015-11-01

    A universality in optimization of trade-off between power and efficiency for low-dissipation Carnot cycles is presented. It is shown that any trade-off measure expressible in terms of efficiency and the ratio of power to its maximum value can be optimized independently of most details of the dynamics and of the coupling to thermal reservoirs. The result is demonstrated on two specific trade-off measures. The first one is designed for finding optimal efficiency for a given output power and clearly reveals diseconomy of engines working at maximum power. As the second example we derive universal lower and upper bounds on the efficiency at maximum trade-off given by the product of power and efficiency. The results are illustrated on a model of a diffusion-based heat engine. Such engines operate in the low-dissipation regime given that the used driving minimizes the work dissipated during the isothermal branches. The peculiarities of the corresponding optimization procedure are reviewed and thoroughly discussed.

  8. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    PubMed

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number. PMID:25225935

  9. Optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits.

    PubMed

    Ozkan, Fahri; Tuna, M Cihat; Baylar, Ahmet; Ozturk, Mualla

    2014-01-01

    Oxygen is an important component of water quality and its ability to sustain life. Water aeration is the process of introducing air into a body of water to increase its oxygen saturation. Water aeration can be accomplished in a variety of ways, for instance, closed-conduit aeration. High-speed flow in a closed conduit involves air-water mixture flow. The air flow results from the subatmospheric pressure downstream of the gate. The air entrained by the high-speed flow is supplied by the air vent. The air entrained into the flow in the form of a large number of bubbles accelerates oxygen transfer and hence also increases aeration efficiency. In the present work, the optimum air-demand ratio for maximum aeration efficiency in high-head gated circular conduits was studied experimentally. Results showed that aeration efficiency increased with the air-demand ratio to a certain point and then aeration efficiency did not change with a further increase of the air-demand ratio. Thus, there was an optimum value for the air-demand ratio, depending on the Froude number, which provides maximum aeration efficiency. Furthermore, a design formula for aeration efficiency was presented relating aeration efficiency to the air-demand ratio and Froude number.

  10. Curating NASA's future extraterrestrial sample collections: How do we achieve maximum proficiency?

    NASA Astrophysics Data System (ADS)

    McCubbin, Francis; Evans, Cynthia; Allton, Judith; Fries, Marc; Righter, Kevin; Zolensky, Michael; Zeigler, Ryan

    2016-07-01

    Introduction: The Astromaterials Acquisition and Curation Office (henceforth referred to herein as NASA Curation Office) at NASA Johnson Space Center (JSC) is responsible for curating all of NASA's extraterrestrial samples. Under the governing document, NASA Policy Directive (NPD) 7100.10E "Curation of Extraterrestrial Materials", JSC is charged with "The curation of all extraterrestrial material under NASA control, including future NASA missions." The Directive goes on to define Curation as including "…documentation, preservation, preparation, and distribution of samples for research, education, and public outreach." Here we describe some of the ongoing efforts to ensure that the future activities of the NASA Curation Office are working to-wards a state of maximum proficiency. Founding Principle: Curatorial activities began at JSC (Manned Spacecraft Center before 1973) as soon as design and construction planning for the Lunar Receiving Laboratory (LRL) began in 1964 [1], not with the return of the Apollo samples in 1969, nor with the completion of the LRL in 1967. This practice has since proven that curation begins as soon as a sample return mission is conceived, and this founding principle continues to return dividends today [e.g., 2]. The Next Decade: Part of the curation process is planning for the future, and we refer to these planning efforts as "advanced curation" [3]. Advanced Curation is tasked with developing procedures, technology, and data sets necessary for curating new types of collections as envisioned by NASA exploration goals. We are (and have been) planning for future curation, including cold curation, extended curation of ices and volatiles, curation of samples with special chemical considerations such as perchlorate-rich samples, curation of organically- and biologically-sensitive samples, and the use of minimally invasive analytical techniques (e.g., micro-CT, [4]) to characterize samples. These efforts will be useful for Mars Sample Return

  11. Universal efficiency bounds of weak-dissipative thermodynamic cycles at the maximum power output.

    PubMed

    Guo, Juncheng; Wang, Junyi; Wang, Yuan; Chen, Jincan

    2013-01-01

    Based on the assumption of weak dissipation introduced by Esposito et al. [Phys. Rev. Lett. 105, 150603 (2010)], analytic expressions for the efficiency bounds of several classes of typical thermodynamic cycles at the maximum power output are derived. The results obtained are of universal significance. They can be used to conveniently reveal the general characteristics of not only Carnot heat engines, but also isothermal chemical engines, non-Carnot heat engines, flux flow engines, gravitational engines, quantum Carnot heat engines, and two-level quantum Carnot engines at the maximum power output and to directly draw many important conclusions in the literature.

  12. Efficiency at maximum power of thermochemical engines with near-independent particles.

    PubMed

    Luo, Xiaoguang; Liu, Nian; Qiu, Teng

    2016-03-01

    Two-reservoir thermochemical engines are established by using near-independent particles (including Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein particles) as the working substance. Particle and heat fluxes can be formed based on the temperature and chemical potential gradients between two different reservoirs. A rectangular-type energy filter with width Γ is introduced for each engine to weaken the coupling between the particle and heat fluxes. The efficiency at maximum power of each particle system decreases monotonously from an upper bound η(+) to a lower bound η(-) when Γ increases from 0 to ∞. It is found that the η(+) values for all three systems are bounded by η(C)/2 ≤ η(+) ≤ η(C)/(2-η(C)) due to strong coupling, where η(C) is the Carnot efficiency. For the Bose-Einstein system, it is found that the upper bound is approximated by the Curzon-Ahlborn efficiency: η(CA)=1-sqrt[1-η(C)]. When Γ → ∞, the intrinsic maximum powers are proportional to the square of the temperature difference of the two reservoirs for all three systems, and the corresponding lower bounds of efficiency at maximum power can be simplified in the same form of η(-)=η(C)/[1+a(0)(2-η(C))].

  13. Efficiency at maximum power of thermochemical engines with near-independent particles

    NASA Astrophysics Data System (ADS)

    Luo, Xiaoguang; Liu, Nian; Qiu, Teng

    2016-03-01

    Two-reservoir thermochemical engines are established by using near-independent particles (including Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein particles) as the working substance. Particle and heat fluxes can be formed based on the temperature and chemical potential gradients between two different reservoirs. A rectangular-type energy filter with width Γ is introduced for each engine to weaken the coupling between the particle and heat fluxes. The efficiency at maximum power of each particle system decreases monotonously from an upper bound η+ to a lower bound η- when Γ increases from 0 to ∞ . It is found that the η+ values for all three systems are bounded by ηC/2 ≤η+≤ηC/(2 -ηC ) due to strong coupling, where ηC is the Carnot efficiency. For the Bose-Einstein system, it is found that the upper bound is approximated by the Curzon-Ahlborn efficiency: ηCA=1 -√{1 -ηC } . When Γ →∞ , the intrinsic maximum powers are proportional to the square of the temperature difference of the two reservoirs for all three systems, and the corresponding lower bounds of efficiency at maximum power can be simplified in the same form of η-=ηC/[1 +a0(2 -ηC ) ] .

  14. Energy-Efficient Algorithm for Sensor Networks with Non-Uniform Maximum Transmission Range

    PubMed Central

    Yu, Yimin; Song, Chao; Liu, Ming; Gong, Haigang

    2011-01-01

    In wireless sensor networks (WSNs), the energy hole problem is a key factor affecting the network lifetime. In a circular multi-hop sensor network (modeled as concentric coronas), the optimal transmission ranges of all coronas can effectively improve network lifetime. In this paper, we investigate WSNs with non-uniform maximum transmission ranges, where sensor nodes deployed in different regions may differ in their maximum transmission range. Then, we propose an Energy-efficient algorithm for Non-uniform Maximum Transmission range (ENMT), which can search approximate optimal transmission ranges of all coronas in order to prolong network lifetime. Furthermore, the simulation results indicate that ENMT performs better than other algorithms. PMID:22163950

  15. Efficiency at maximum power output of linear irreversible Carnot-like heat engines.

    PubMed

    Wang, Yang; Tu, Z C

    2012-01-01

    The efficiency at maximum power output of linear irreversible Carnot-like heat engines is investigated based on the assumption that the rate of irreversible entropy production of the working substance in each "isothermal" process is a quadratic form of the heat exchange rate between the working substance and the reservoir. It is found that the maximum power output corresponds to minimizing the irreversible entropy production in two isothermal processes of the Carnot-like cycle, and that the efficiency at maximum power output has the form η(mP)=η(C)/(2-γη(C)), where η(C) is the Carnot efficiency, while γ depends on the heat transfer coefficients between the working substance and two reservoirs. The value of η(mP) is bounded between η(-)≡η(C)/2 and η(+)≡η(C)/(2-η(C)). These results are consistent with those obtained by Chen and Yan [J. Chem. Phys. 90, 3740 (1989)] based on the endoreversible assumption, those obtained by Esposito et al. [Phys. Rev. Lett. 105, 150603 (2010)] based on the low-dissipation assumption, and those obtained by Schmiedl and Seifert [Europhys. Lett. 81, 20003 (2008)] for stochastic heat engines which in fact also satisfy the low-dissipation assumption. Additionally, we find that the endoreversible assumption happens to hold for Carnot-like heat engines operating at the maximum power output based on our fundamental assumption, and that the Carnot-like heat engines that we focused on do not strictly satisfy the low-dissipation assumption, which implies that the low-dissipation assumption or our fundamental assumption is a sufficient but non-necessary condition for the validity of η(mP)=η(C)/(2-γη(C)) as well as the existence of two bounds, η(-)≡η(C)/2 and η(+)≡η(C)/(2-η(C)).

  16. Efficiency at maximum power of a quantum Otto cycle within finite-time or irreversible thermodynamics.

    PubMed

    Wu, Feilong; He, Jizhou; Ma, Yongli; Wang, Jianhui

    2014-12-01

    We consider the efficiency at maximum power of a quantum Otto engine, which uses a spin or a harmonic system as its working substance and works between two heat reservoirs at constant temperatures T(h) and T(c) (efficiencies at maximum power based on these two different kinds of quantum systems are bounded from the upper side by the same expression η(mp)≤η(+)≡η(C)(2)/[η(C)-(1-η(C))ln(1-η(C))] with η(C)=1-T(c)/T(h) as the Carnot efficiency. This expression η(mp) possesses the same universality of the CA efficiency η(CA)=1-√(1-η(C)) at small relative temperature difference. Within the context of irreversible thermodynamics, we calculate the Onsager coefficients and show that the value of η(CA) is indeed the upper bound of EMP for an Otto engine working in the linear-response regime.

  17. Efficiency at maximum power of a quantum Otto cycle within finite-time or irreversible thermodynamics

    NASA Astrophysics Data System (ADS)

    Wu, Feilong; He, Jizhou; Ma, Yongli; Wang, Jianhui

    2014-12-01

    We consider the efficiency at maximum power of a quantum Otto engine, which uses a spin or a harmonic system as its working substance and works between two heat reservoirs at constant temperatures Th and Tc (efficiencies at maximum power based on these two different kinds of quantum systems are bounded from the upper side by the same expression ηmp≤η+≡ηC2/[ηC-(1 -ηC) ln(1 -ηC) ] with ηC=1 -Tc/Th as the Carnot efficiency. This expression ηmp possesses the same universality of the CA efficiency ηCA=1 -√{1 -ηC } at small relative temperature difference. Within the context of irreversible thermodynamics, we calculate the Onsager coefficients and show that the value of ηCA is indeed the upper bound of EMP for an Otto engine working in the linear-response regime.

  18. Efficiency and its bounds for thermal engines at maximum power using Newton's law of cooling.

    PubMed

    Yan, H; Guo, Hao

    2012-01-01

    We study a thermal engine model for which Newton's cooling law is obeyed during heat transfer processes. The thermal efficiency and its bounds at maximum output power are derived and discussed. This model, though quite simple, can be applied not only to Carnot engines but also to four other types of engines. For the long thermal contact time limit, new bounds, tighter than what were known before, are obtained. In this case, this model can simulate Otto, Joule-Brayton, Diesel, and Atkinson engines. While in the short contact time limit, which corresponds to the Carnot cycle, the same efficiency bounds as that from Esposito et al. [Phys. Rev. Lett. 105, 150603 (2010)] are derived. In both cases, the thermal efficiency decreases as the ratio between the heat capacities of the working medium during heating and cooling stages increases. This might provide instructions for designing real engines.

  19. Efficiency and its bounds for thermal engines at maximum power using Newton's law of cooling

    NASA Astrophysics Data System (ADS)

    Yan, H.; Guo, Hao

    2012-01-01

    We study a thermal engine model for which Newton's cooling law is obeyed during heat transfer processes. The thermal efficiency and its bounds at maximum output power are derived and discussed. This model, though quite simple, can be applied not only to Carnot engines but also to four other types of engines. For the long thermal contact time limit, new bounds, tighter than what were known before, are obtained. In this case, this model can simulate Otto, Joule-Brayton, Diesel, and Atkinson engines. While in the short contact time limit, which corresponds to the Carnot cycle, the same efficiency bounds as that from Esposito [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.105.150603 105, 150603 (2010)] are derived. In both cases, the thermal efficiency decreases as the ratio between the heat capacities of the working medium during heating and cooling stages increases. This might provide instructions for designing real engines.

  20. Efficiency at maximum power output of an irreversible Carnot-like cycle with internally dissipative friction.

    PubMed

    Wang, Jianhui; He, Jizhou

    2012-11-01

    We investigate the efficiency at the maximum power output (EMP) of an irreversible Carnot engine performing finite-time cycles between two reservoirs at constant temperatures T(h) and T(c) (efficiency, whether the internally dissipative friction is considered or not. When dissipations of two "isothermal" and two "adiabatic" processes are symmetric, respectively, and the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation, the Curzon-Ahlborn (CA) efficiency η(CA) = 1-sqrt[T(c)/T(h)] is derived.

  1. Efficiency at maximum power output for an engine with a passive piston

    NASA Astrophysics Data System (ADS)

    Sano, Tomohiko G.; Hayakawa, Hisao

    2016-08-01

    Efficiency at maximum power (MP) output for an engine with a passive piston without mechanical controls between two reservoirs is studied theoretically. We enclose a hard core gas partitioned by a massive piston in a temperature-controlled container and analyze the efficiency at MP under a heating and cooling protocol without controlling the pressure acting on the piston from outside. We find the following three results: (i) The efficiency at MP for a dilute gas is close to the Chambadal-Novikov-Curzon-Ahlborn (CNCA) efficiency if we can ignore the sidewall friction and the loss of energy between a gas particle and the piston, while (ii) the efficiency for a moderately dense gas becomes smaller than the CNCA efficiency even when the temperature difference of the reservoirs is small. (iii) Introducing the Onsager matrix for an engine with a passive piston, we verify that the tight coupling condition for the matrix of the dilute gas is satisfied, while that of the moderately dense gas is not satisfied because of the inevitable heat leak. We confirm the validity of these results using the molecular dynamics simulation and introducing an effective mean-field-like model which we call the stochastic mean field model.

  2. Irreversibilities and efficiency at maximum power of heat engines: the illustrative case of a thermoelectric generator.

    PubMed

    Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

    2012-03-01

    Energy conversion efficiency at maximum output power, which embodies the essential characteristics of heat engines, is the main focus of the present work. The so-called Curzon and Ahlborn efficiency η(CA) is commonly believed to be an absolute reference for real heat engines; however, a different but general expression for the case of stochastic heat engines, η(SS), was recently found and then extended to low-dissipation engines. The discrepancy between η(CA) and η(SS) is here analyzed considering different irreversibility sources of heat engines, of both internal and external types. To this end, we choose a thermoelectric generator operating in the strong-coupling regime as a physical system to qualitatively and quantitatively study the impact of the nature of irreversibility on the efficiency at maximum output power. In the limit of pure external dissipation, we obtain η(CA), while η(SS) corresponds to the case of pure internal dissipation. A continuous transition between from one extreme to the other, which may be operated by tuning the different sources of irreversibility, also is evidenced.

  3. Irreversibilities and efficiency at maximum power of heat engines: the illustrative case of a thermoelectric generator.

    PubMed

    Apertet, Y; Ouerdane, H; Goupil, C; Lecoeur, Ph

    2012-03-01

    Energy conversion efficiency at maximum output power, which embodies the essential characteristics of heat engines, is the main focus of the present work. The so-called Curzon and Ahlborn efficiency η(CA) is commonly believed to be an absolute reference for real heat engines; however, a different but general expression for the case of stochastic heat engines, η(SS), was recently found and then extended to low-dissipation engines. The discrepancy between η(CA) and η(SS) is here analyzed considering different irreversibility sources of heat engines, of both internal and external types. To this end, we choose a thermoelectric generator operating in the strong-coupling regime as a physical system to qualitatively and quantitatively study the impact of the nature of irreversibility on the efficiency at maximum output power. In the limit of pure external dissipation, we obtain η(CA), while η(SS) corresponds to the case of pure internal dissipation. A continuous transition between from one extreme to the other, which may be operated by tuning the different sources of irreversibility, also is evidenced. PMID:22587047

  4. Efficient Levenberg-Marquardt minimization of the maximum likelihood estimator for Poisson deviates

    SciTech Connect

    Laurence, T; Chromy, B

    2009-11-10

    Histograms of counted events are Poisson distributed, but are typically fitted without justification using nonlinear least squares fitting. The more appropriate maximum likelihood estimator (MLE) for Poisson distributed data is seldom used. We extend the use of the Levenberg-Marquardt algorithm commonly used for nonlinear least squares minimization for use with the MLE for Poisson distributed data. In so doing, we remove any excuse for not using this more appropriate MLE. We demonstrate the use of the algorithm and the superior performance of the MLE using simulations and experiments in the context of fluorescence lifetime imaging. Scientists commonly form histograms of counted events from their data, and extract parameters by fitting to a specified model. Assuming that the probability of occurrence for each bin is small, event counts in the histogram bins will be distributed according to the Poisson distribution. We develop here an efficient algorithm for fitting event counting histograms using the maximum likelihood estimator (MLE) for Poisson distributed data, rather than the non-linear least squares measure. This algorithm is a simple extension of the common Levenberg-Marquardt (L-M) algorithm, is simple to implement, quick and robust. Fitting using a least squares measure is most common, but it is the maximum likelihood estimator only for Gaussian-distributed data. Non-linear least squares methods may be applied to event counting histograms in cases where the number of events is very large, so that the Poisson distribution is well approximated by a Gaussian. However, it is not easy to satisfy this criterion in practice - which requires a large number of events. It has been well-known for years that least squares procedures lead to biased results when applied to Poisson-distributed data; a recent paper providing extensive characterization of these biases in exponential fitting is given. The more appropriate measure based on the maximum likelihood estimator (MLE

  5. High Output Maximum Efficiency Resonator (HOMER) Laser for NASA's Global Ecosystem Dynamics Investigation (GEDI) Lidar Mission

    NASA Technical Reports Server (NTRS)

    Stysley, Paul; Coyle, Barry; Clarke, Greg; Poulios, Demetrios; Kay, Richard

    2015-01-01

    The Global Ecosystems Dynamics Investigation (GEDI) is a planned mission sending a LIDAR instrument to the International Space Station that will employ three NASA laser transmitters. This instrument will produce parallel tracks on the Earth's surface that will provide global 3D vegetation canopy measurements. To meet the mission goals a total of 5 High Output Maximum Efficiency Resonator lasers will to be built (1 ETU + 3 Flight + 1 spare) in-house at NASA-GSFC. This presentation will summarize the HOMER design, the testing the design has completed in the past, and the plans to successfully build the units needed for the GEDI mission.

  6. Carbon sequestration during the Palaeocene-Eocene Thermal Maximum by an efficient biological pump

    NASA Astrophysics Data System (ADS)

    Ma, Zhongwu; Gray, Ellen; Thomas, Ellen; Murphy, Brandon; Zachos, James; Paytan, Adina

    2014-05-01

    A perturbation of the carbon cycle and biosphere, linked to globally increased temperatures about 55.9 million years ago, characterized the Palaeocene-Eocene Thermal Maximum. Its effect on global oceanic productivity is controversial. Here we present records of marine barite accumulation rates that show distinct peaks during this time interval, suggesting a general increase in export productivity. We propose that changes in marine ecosystems, resulting from high atmospheric partial pressure of CO2 and ocean acidification, led to enhanced carbon export from the photic zone to depth, thereby increasing the efficiency of the biological pump. Higher seawater temperatures at that time increased bacterial activity and organic matter regeneration. Through this process much of the sinking particulate organic matter was probably converted to dissolved inorganic and organic carbon. We estimate that an annual carbon export flux out of the euphotic zone and into the deep ocean waters could have amounted to about 15 Gt during the Palaeocene-Eocene Thermal Maximum. About 0.4% of this carbon is expected to have entered the refractory dissolved organic pool, where it could be sequestered from the atmosphere for tens of thousands of years. Our estimates are consistent with the amount of carbon redistribution expected for the recovery from the Palaeocene-Eocene Thermal Maximum.

  7. An Efficient Steady-State Analysis Method for Large Boolean Networks with High Maximum Node Connectivity

    PubMed Central

    Hong, Changki; Hwang, Jeewon; Cho, Kwang-Hyun; Shin, Insik

    2015-01-01

    Boolean networks have been widely used to model biological processes lacking detailed kinetic information. Despite their simplicity, Boolean network dynamics can still capture some important features of biological systems such as stable cell phenotypes represented by steady states. For small models, steady states can be determined through exhaustive enumeration of all state transitions. As the number of nodes increases, however, the state space grows exponentially thus making it difficult to find steady states. Over the last several decades, many studies have addressed how to handle such a state space explosion. Recently, increasing attention has been paid to a satisfiability solving algorithm due to its potential scalability to handle large networks. Meanwhile, there still lies a problem in the case of large models with high maximum node connectivity where the satisfiability solving algorithm is known to be computationally intractable. To address the problem, this paper presents a new partitioning-based method that breaks down a given network into smaller subnetworks. Steady states of each subnetworks are identified by independently applying the satisfiability solving algorithm. Then, they are combined to construct the steady states of the overall network. To efficiently apply the satisfiability solving algorithm to each subnetwork, it is crucial to find the best partition of the network. In this paper, we propose a method that divides each subnetwork to be smallest in size and lowest in maximum node connectivity. This minimizes the total cost of finding all steady states in entire subnetworks. The proposed algorithm is compared with others for steady states identification through a number of simulations on both published small models and randomly generated large models with differing maximum node connectivities. The simulation results show that our method can scale up to several hundreds of nodes even for Boolean networks with high maximum node connectivity. The

  8. An Efficient Steady-State Analysis Method for Large Boolean Networks with High Maximum Node Connectivity.

    PubMed

    Hong, Changki; Hwang, Jeewon; Cho, Kwang-Hyun; Shin, Insik

    2015-01-01

    Boolean networks have been widely used to model biological processes lacking detailed kinetic information. Despite their simplicity, Boolean network dynamics can still capture some important features of biological systems such as stable cell phenotypes represented by steady states. For small models, steady states can be determined through exhaustive enumeration of all state transitions. As the number of nodes increases, however, the state space grows exponentially thus making it difficult to find steady states. Over the last several decades, many studies have addressed how to handle such a state space explosion. Recently, increasing attention has been paid to a satisfiability solving algorithm due to its potential scalability to handle large networks. Meanwhile, there still lies a problem in the case of large models with high maximum node connectivity where the satisfiability solving algorithm is known to be computationally intractable. To address the problem, this paper presents a new partitioning-based method that breaks down a given network into smaller subnetworks. Steady states of each subnetworks are identified by independently applying the satisfiability solving algorithm. Then, they are combined to construct the steady states of the overall network. To efficiently apply the satisfiability solving algorithm to each subnetwork, it is crucial to find the best partition of the network. In this paper, we propose a method that divides each subnetwork to be smallest in size and lowest in maximum node connectivity. This minimizes the total cost of finding all steady states in entire subnetworks. The proposed algorithm is compared with others for steady states identification through a number of simulations on both published small models and randomly generated large models with differing maximum node connectivities. The simulation results show that our method can scale up to several hundreds of nodes even for Boolean networks with high maximum node connectivity. The

  9. Potential Impact of Adopting Maximum Technologies as Minimum Efficiency Performance Standards in the U.S. Residential Sector

    SciTech Connect

    Letschert, Virginie; Desroches, Louis-Benoit; McNeil, Michael; Saheb, Yamina

    2010-05-03

    The US Department of Energy (US DOE) has placed lighting and appliance standards at a very high priority of the U.S. energy policy. However, the maximum energy savings and CO2 emissions reduction achievable via minimum efficiency performance standards (MEPS) has not yet been fully characterized. The Bottom Up Energy Analysis System (BUENAS), first developed in 2007, is a global, generic, and modular tool designed to provide policy makers with estimates of potential impacts resulting from MEPS for a variety of products, at the international and/or regional level. Using the BUENAS framework, we estimated potential national energy savings and CO2 emissions mitigation in the US residential sector that would result from the most aggressive policy foreseeable: standards effective in 2014 set at the current maximum technology (Max Tech) available on the market. This represents the most likely characterization of what can be maximally achieved through MEPS in the US. The authors rely on the latest Technical Support Documents and Analytical Tools published by the U.S. Department of Energy as a source to determine appliance stock turnover and projected efficiency scenarios of what would occur in the absence of policy. In our analysis, national impacts are determined for the following end uses: lighting, television, refrigerator-freezers, central air conditioning, room air conditioning, residential furnaces, and water heating. The analyzed end uses cover approximately 65percent of site energy consumption in the residential sector (50percent of the electricity consumption and 80percent of the natural gas and LPG consumption). This paper uses this BUENAS methodology to calculate that energy savings from Max Tech for the U.S. residential sector products covered in this paper will reach an 18percent reduction in electricity demand compared to the base case and 11percent in Natural Gas and LPG consumption by 2030 The methodology results in reductions in CO2 emissions of a similar

  10. H. B. Reitlinger and the origins of the efficiency at maximum power formula for heat engines

    NASA Astrophysics Data System (ADS)

    Vaudrey, Alexandre; Lanzetta, François; Feidt, Michel

    2014-12-01

    Even if not so ancient, the history of the heat engine efficiency at maximum power expression has been yet turbulent. More than a decade after the publication of the seminal article by Curzon and Ahlborn in 1975, two older works by Chambadal and Novikov were rediscovered, both dating from 1957. Then, some years ago, the name of Yvon arose from a textual reference to this famous relation in a conference article published in 1955. Thanks to a historical study of French-written books not published for a long time, and since never translated into other languages, we bring to light in this paper that this relation was actually first proposed by Henri B. Reitlinger in 1929.

  11. Efficient method for computing the maximum-likelihood quantum state from measurements with additive Gaussian noise.

    PubMed

    Smolin, John A; Gambetta, Jay M; Smith, Graeme

    2012-02-17

    We provide an efficient method for computing the maximum-likelihood mixed quantum state (with density matrix ρ) given a set of measurement outcomes in a complete orthonormal operator basis subject to Gaussian noise. Our method works by first changing basis yielding a candidate density matrix μ which may have nonphysical (negative) eigenvalues, and then finding the nearest physical state under the 2-norm. Our algorithm takes at worst O(d(4)) for the basis change plus O(d(3)) for finding ρ where d is the dimension of the quantum state. In the special case where the measurement basis is strings of Pauli operators, the basis change takes only O(d(3)) as well. The workhorse of the algorithm is a new linear-time method for finding the closest probability distribution (in Euclidean distance) to a set of real numbers summing to one.

  12. Calibration of STUD+ parameters to achieve optimally efficient broadband adiabatic decoupling in a single transient

    PubMed

    Bendall; Skinner

    1998-10-01

    To provide the most efficient conditions for spin decoupling with least RF power, master calibration curves are provided for the maximum centerband amplitude, and the minimum amplitude for the largest cycling sideband, resulting from STUD+ adiabatic decoupling applied during a single free induction decay. The principal curve is defined as a function of the four most critical experimental input parameters: the maximum amplitude of the RF field, RFmax, the length of the sech/tanh pulse, Tp, the extent of the frequency sweep, bwdth, and the coupling constant, Jo. Less critical parameters, the effective (or actual) decoupled bandwidth, bweff, and the sech/tanh truncation factor, beta, which become more important as bwdth is decreased, are calibrated in separate curves. The relative importance of nine additional factors in determining optimal decoupling performance in a single transient are considered. Specific parameters for efficient adiabatic decoupling can be determined via a set of four equations which will be most useful for 13C decoupling, covering the range of one-bond 13C1H coupling constants from 125 to 225 Hz, and decoupled bandwidths of 7 to 100 kHz, with a bandwidth of 100 kHz being the requirement for a 2 GHz spectrometer. The four equations are derived from a recent vector model of adiabatic decoupling, and experiment, supported by computer simulations. The vector model predicts an inverse linear relation between the centerband and maximum sideband amplitudes, and it predicts a simple parabolic relationship between maximum sideband amplitude and the product JoTp. The ratio bwdth/(RFmax)2 can be viewed as a characteristic time scale, tauc, affecting sideband levels, with tauc approximately Tp giving the most efficient STUD+ decoupling, as suggested by the adiabatic condition. Functional relationships between bwdth and less critical parameters, bweff and beta, for efficient decoupling can be derived from Bloch-equation calculations of the inversion profile

  13. An efficient genetic algorithm for maximum coverage deployment in wireless sensor networks.

    PubMed

    Yoon, Yourim; Kim, Yong-Hyuk

    2013-10-01

    Sensor networks have a lot of applications such as battlefield surveillance, environmental monitoring, and industrial diagnostics. Coverage is one of the most important performance metrics for sensor networks since it reflects how well a sensor field is monitored. In this paper, we introduce the maximum coverage deployment problem in wireless sensor networks and analyze the properties of the problem and its solution space. Random deployment is the simplest way to deploy sensor nodes but may cause unbalanced deployment and therefore, we need a more intelligent way for sensor deployment. We found that the phenotype space of the problem is a quotient space of the genotype space in a mathematical view. Based on this property, we propose an efficient genetic algorithm using a novel normalization method. A Monte Carlo method is adopted to design an efficient evaluation function, and its computation time is decreased without loss of solution quality using a method that starts from a small number of random samples and gradually increases the number for subsequent generations. The proposed genetic algorithms could be further improved by combining with a well-designed local search. The performance of the proposed genetic algorithm is shown by a comparative experimental study. When compared with random deployment and existing methods, our genetic algorithm was not only about twice faster, but also showed significant performance improvement in quality.

  14. Efficiency at maximum power of a heat engine working with a two-level atomic system

    NASA Astrophysics Data System (ADS)

    Wang, Rui; Wang, Jianhui; He, Jizhou; Ma, Yongli

    2013-04-01

    We consider the finite-time operation of a quantum heat engine whose working substance is composed of a two-level atomic system. The engine cycle, consisting of two quantum adiabatic and two quantum isochoric (constant-frequency) processes and working between two heat reservoirs at temperatures Th and Tc(efficiency at maximum power output (EMP) and analyze numerically the effects of the times taken for two adiabatic and two isochoric processes on the EMP. In the absence of internally dissipative friction, we find that the EMP is bounded from the upper side by a function of the Carnot efficiency ηC, η+=ηC2/[ηC-(1-ηC)ln(1-ηC)], with ηC=1-Tc/Th. This analytic expression is confirmed by our exact numerical result and is identical to the one derived in an engine model based on a mesoscopic or macroscopic system. If the internal friction is included, we find that the EMP decreases as the friction coefficient increases.

  15. Efficiency at maximum power of a quantum heat engine based on two coupled oscillators.

    PubMed

    Wang, Jianhui; Ye, Zhuolin; Lai, Yiming; Li, Weisheng; He, Jizhou

    2015-06-01

    We propose and theoretically investigate a system of two coupled harmonic oscillators as a heat engine. We show how these two coupled oscillators within undamped regime can be controlled to realize an Otto cycle that consists of two adiabatic and two isochoric processes. During the two isochores the harmonic system is embedded in two heat reservoirs at constant temperatures T(h) and T(c)(efficiency at maximum power (EMP) η* to be a function of the Carnot efficiency η(C)(=1-T(c)/T(h)): η*≤η(+)≡η(C)(2)/[η(C)-(1-η(C))ln(1-η(C))], identical to those previously derived from ideal (noninteracting) microscopic, mesoscopic, and macroscopic systems.

  16. Efficiency at maximum power of a quantum heat engine based on two coupled oscillators

    NASA Astrophysics Data System (ADS)

    Wang, Jianhui; Ye, Zhuolin; Lai, Yiming; Li, Weisheng; He, Jizhou

    2015-06-01

    We propose and theoretically investigate a system of two coupled harmonic oscillators as a heat engine. We show how these two coupled oscillators within undamped regime can be controlled to realize an Otto cycle that consists of two adiabatic and two isochoric processes. During the two isochores the harmonic system is embedded in two heat reservoirs at constant temperatures Th and Tc(efficiency at maximum power (EMP) η* to be a function of the Carnot efficiency ηC(=1 -Tc/Th) : η*≤η+≡ηC2/[ηC-(1 -ηC) ln(1 -ηC) ] , identical to those previously derived from ideal (noninteracting) microscopic, mesoscopic, and macroscopic systems.

  17. Air Force Achieves Fuel Efficiency through Industry Best Practices

    SciTech Connect

    2012-12-01

    The U.S. Air Force’s Air Mobility Command (AMC) is changing the way it does business. It is saving energy and money through an aircraft fleet fuel-efficiency program inspired by private industry best practices and ideas resulting from the empowered fuel savings culture.

  18. Efficiency of neural network-based combinatorial model predicting optimal culture conditions for maximum biomass yields in hairy root cultures.

    PubMed

    Mehrotra, Shakti; Prakash, O; Khan, Feroz; Kukreja, A K

    2013-02-01

    KEY MESSAGE : ANN-based combinatorial model is proposed and its efficiency is assessed for the prediction of optimal culture conditions to achieve maximum productivity in a bioprocess in terms of high biomass. A neural network approach is utilized in combination with Hidden Markov concept to assess the optimal values of different environmental factors that result in maximum biomass productivity of cultured tissues after definite culture duration. Five hidden Markov models (HMMs) were derived for five test culture conditions, i.e. pH of liquid growth medium, volume of medium per culture vessel, sucrose concentration (%w/v) in growth medium, nitrate concentration (g/l) in the medium and finally the density of initial inoculum (g fresh weight) per culture vessel and their corresponding fresh weight biomass. The artificial neural network (ANN) model was represented as the function of these five Markov models, and the overall simulation of fresh weight biomass was done with this combinatorial ANN-HMM. The empirical results of Rauwolfia serpentina hairy roots were taken as model and compared with simulated results obtained from pure ANN and ANN-HMMs. The stochastic testing and Cronbach's α-value of pure and combinatorial model revealed more internal consistency and skewed character (0.4635) in histogram of ANN-HMM compared to pure ANN (0.3804). The simulated results for optimal conditions of maximum fresh weight production obtained from ANN-HMM and ANN model closely resemble the experimentally optimized culture conditions based on which highest fresh weight was obtained. However, only 2.99 % deviation from the experimental values could be observed in the values obtained from combinatorial model when compared to the pure ANN model (5.44 %). This comparison showed 45 % better potential of combinatorial model for the prediction of optimal culture conditions for the best growth of hairy root cultures.

  19. Telescoping Solar Array Concept for Achieving High Packaging Efficiency

    NASA Technical Reports Server (NTRS)

    Mikulas, Martin; Pappa, Richard; Warren, Jay; Rose, Geoff

    2015-01-01

    Lightweight, high-efficiency solar arrays are required for future deep space missions using high-power Solar Electric Propulsion (SEP). Structural performance metrics for state-of-the art 30-50 kW flexible blanket arrays recently demonstrated in ground tests are approximately 40 kW/cu m packaging efficiency, 150 W/kg specific power, 0.1 Hz deployed stiffness, and 0.2 g deployed strength. Much larger arrays with up to a megawatt or more of power and improved packaging and specific power are of interest to mission planners for minimizing launch and life cycle costs of Mars exploration. A new concept referred to as the Compact Telescoping Array (CTA) with 60 kW/cu m packaging efficiency at 1 MW of power is described herein. Performance metrics as a function of array size and corresponding power level are derived analytically and validated by finite element analysis. Feasible CTA packaging and deployment approaches are also described. The CTA was developed, in part, to serve as a NASA reference solar array concept against which other proposed designs of 50-1000 kW arrays for future high-power SEP missions could be compared.

  20. 10 CFR 435.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise Residential Buildings. § 435.7 Water used to achieve energy efficiency. ... 10 Energy 3 2011-01-01 2011-01-01 false Water used to achieve energy efficiency. 435.7 Section...

  1. 10 CFR 433.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 3 2011-01-01 2011-01-01 false Water used to achieve energy efficiency. 433.7 Section 433.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR THE DESIGN AND... achieve energy efficiency....

  2. 10 CFR 433.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Water used to achieve energy efficiency. 433.7 Section 433.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.7 Water used to achieve energy efficiency....

  3. 10 CFR 433.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Water used to achieve energy efficiency. 433.7 Section 433.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR THE DESIGN AND... achieve energy efficiency....

  4. 10 CFR 433.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Water used to achieve energy efficiency. 433.7 Section 433.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.7 Water used to achieve energy efficiency....

  5. 10 CFR 433.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Water used to achieve energy efficiency. 433.7 Section 433.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL COMMERCIAL AND MULTI-FAMILY HIGH-RISE RESIDENTIAL BUILDINGS § 433.7 Water used to achieve energy efficiency....

  6. Barriers to Achieving Textbook Multigrid Efficiency (TME) in CFD

    NASA Technical Reports Server (NTRS)

    Brandt, Achi

    1998-01-01

    As a guide to attaining this optimal performance for general CFD problems, the table below lists every foreseen kind of computational difficulty for achieving that goal, together with the possible ways for resolving that difficulty, their current state of development, and references. Included in the table are staggered and nonstaggered, conservative and nonconservative discretizations of viscous and inviscid, incompressible and compressible flows at various Mach numbers, as well as a simple (algebraic) turbulence model and comments on chemically reacting flows. The listing of associated computational barriers involves: non-alignment of streamlines or sonic characteristics with the grids; recirculating flows; stagnation points; discretization and relaxation on and near shocks and boundaries; far-field artificial boundary conditions; small-scale singularities (meaning important features, such as the complete airplane, which are not visible on some of the coarse grids); large grid aspect ratios; boundary layer resolution; and grid adaption.

  7. Laboratory 2000--the challenge of achieving efficiency and compliance.

    PubMed

    Potter, J A

    2001-01-01

    Significant advances within the field of laboratory automation and instrumentation have greatly benefited the pharmaceutical industry in its quest to discover, develop and monitor the quality of its products. Necessitated by the need for efficiency and greater productivity, faster and more cost-effective means of analyses exist in the form of devices made up of complex electromechanical components, all logically controlled and most with the capability to interface with sophisticated information systems. This benefit does come with a price, a greater responsibility to ensure data quality while complying with increased regulatory requirements. Commitment to this responsibility presents a substantial challenge to scientists and managers throughout the industry. Due diligence must be demonstrated. A comprehensive evaluation of every laboratory system utilized, a solid plan of action for correcting any known deficiencies including upgrades or complete replacement, and an accurate monitoring procedure with the ability to measure progress are all absolute necessities to ensure success. Crossfunctional team effort and communication must transpire with full managerial support. Vendors need to be audited, made aware of any functional or quality inadequacies they possess as well as the pharmaceutical industry's expectation for these shortcomings to be rapidly corrected. Suppliers of these systems should also be encouraged to provide complete 'off-the-shelf solutions' to eliminate the need for in-house customization. The requirements for regulatory compliance in today's electronic environment have been well publicized. The players involved are not only listening, but also taking the necessary steps to retain and improve efficiency without sacrificing quality. With the proper measures, planning and action, a highly automated, cost-effective and compliant laboratory operation can become a reality.

  8. The tolerance efficiency of Panicum maximum and Helianthus annuus in TNT-contaminated soil and nZVI-contaminated soil.

    PubMed

    Jiamjitrpanich, Waraporn; Parkpian, Preeda; Polprasert, Chongrak; Laurent, François; Kosanlavit, Rachain

    2012-01-01

    This study was designed to compare the initial method for phytoremediation involving germination and transplantation. The study was also to determine the tolerance efficiency of Panicum maximum (Purple guinea grass) and Helianthus annuus (Sunflower) in TNT-contaminated soil and nZVI-contaminated soil. It was found that the transplantation of Panicum maximum and Helianthus annuus was more suitable than germination as the initiate method of nano-phytoremediation potting test. The study also showed that Panicum maximum was more tolerance than Helianthus annuus in TNT and nZVI-contaminated soil. Therefore, Panicum maximum in the transplantation method should be selected as a hyperaccumulated plant for nano-phytoremediation potting tests. Maximum tolerance dosage of Panicum maximum to TNT-concentration soil was 320 mg/kg and nZVI-contaminated soil was 1000 mg/kg in the transplantation method.

  9. An Algorithm for Efficient Maximum Likelihood Estimation and Confidence Interval Determination in Nonlinear Estimation Problems

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick Charles

    1985-01-01

    An algorithm for maximum likelihood (ML) estimation is developed with an efficient method for approximating the sensitivities. The algorithm was developed for airplane parameter estimation problems but is well suited for most nonlinear, multivariable, dynamic systems. The ML algorithm relies on a new optimization method referred to as a modified Newton-Raphson with estimated sensitivities (MNRES). MNRES determines sensitivities by using slope information from local surface approximations of each output variable in parameter space. The fitted surface allows sensitivity information to be updated at each iteration with a significant reduction in computational effort. MNRES determines the sensitivities with less computational effort than using either a finite-difference method or integrating the analytically determined sensitivity equations. MNRES eliminates the need to derive sensitivity equations for each new model, thus eliminating algorithm reformulation with each new model and providing flexibility to use model equations in any format that is convenient. A random search technique for determining the confidence limits of ML parameter estimates is applied to nonlinear estimation problems for airplanes. The confidence intervals obtained by the search are compared with Cramer-Rao (CR) bounds at the same confidence level. It is observed that the degree of nonlinearity in the estimation problem is an important factor in the relationship between CR bounds and the error bounds determined by the search technique. The CR bounds were found to be close to the bounds determined by the search when the degree of nonlinearity was small. Beale's measure of nonlinearity is developed in this study for airplane identification problems; it is used to empirically correct confidence levels for the parameter confidence limits. The primary utility of the measure, however, was found to be in predicting the degree of agreement between Cramer-Rao bounds and search estimates.

  10. Work output and efficiency at maximum power of linear irreversible heat engines operating with a finite-sized heat source.

    PubMed

    Izumida, Yuki; Okuda, Koji

    2014-05-01

    We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart.

  11. Work output and efficiency at maximum power of linear irreversible heat engines operating with a finite-sized heat source.

    PubMed

    Izumida, Yuki; Okuda, Koji

    2014-05-01

    We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart. PMID:24856684

  12. Work Output and Efficiency at Maximum Power of Linear Irreversible Heat Engines Operating with a Finite-Sized Heat Source

    NASA Astrophysics Data System (ADS)

    Izumida, Yuki; Okuda, Koji

    2014-05-01

    We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart.

  13. Systematic approach to determination of maximum achievable capture capacity via leaching and carbonation processes for alkaline steelmaking wastes in a rotating packed bed.

    PubMed

    Pan, Shu-Yuan; Chiang, Pen-Chi; Chen, Yi-Hung; Chen, Chun-Da; Lin, Hsun-Yu; Chang, E-E

    2013-01-01

    Accelerated carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was performed in a rotating packed bed (RPB) as a promising process for both CO2 fixation and wastewater treatment. The maximum achievable capture capacity (MACC) via leaching and carbonation processes for BOFS in an RPB was systematically determined throughout this study. The leaching behavior of various metal ions from the BOFS into the CRW was investigated by a kinetic model. In addition, quantitative X-ray diffraction (QXRD) using the Rietveld method was carried out to determine the process chemistry of carbonation of BOFS with CRW in an RPB. According to the QXRD results, the major mineral phases reacting with CO2 in BOFS were Ca(OH)2, Ca2(HSiO4)(OH), CaSiO3, and Ca2Fe1.04Al0.986O5. Meanwhile, the carbonation product was identified as calcite according to the observations of SEM, XEDS, and mappings. Furthermore, the MACC of the lab-scale RPB process was determined by balancing the carbonation conversion and energy consumption. In that case, the overall energy consumption, including grinding, pumping, stirring, and rotating processes, was estimated to be 707 kWh/t-CO2. It was thus concluded that CO2 capture by accelerated carbonation of BOFS could be effectively and efficiently performed by coutilizing with CRW in an RPB. PMID:24236803

  14. Systematic approach to determination of maximum achievable capture capacity via leaching and carbonation processes for alkaline steelmaking wastes in a rotating packed bed.

    PubMed

    Pan, Shu-Yuan; Chiang, Pen-Chi; Chen, Yi-Hung; Chen, Chun-Da; Lin, Hsun-Yu; Chang, E-E

    2013-01-01

    Accelerated carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was performed in a rotating packed bed (RPB) as a promising process for both CO2 fixation and wastewater treatment. The maximum achievable capture capacity (MACC) via leaching and carbonation processes for BOFS in an RPB was systematically determined throughout this study. The leaching behavior of various metal ions from the BOFS into the CRW was investigated by a kinetic model. In addition, quantitative X-ray diffraction (QXRD) using the Rietveld method was carried out to determine the process chemistry of carbonation of BOFS with CRW in an RPB. According to the QXRD results, the major mineral phases reacting with CO2 in BOFS were Ca(OH)2, Ca2(HSiO4)(OH), CaSiO3, and Ca2Fe1.04Al0.986O5. Meanwhile, the carbonation product was identified as calcite according to the observations of SEM, XEDS, and mappings. Furthermore, the MACC of the lab-scale RPB process was determined by balancing the carbonation conversion and energy consumption. In that case, the overall energy consumption, including grinding, pumping, stirring, and rotating processes, was estimated to be 707 kWh/t-CO2. It was thus concluded that CO2 capture by accelerated carbonation of BOFS could be effectively and efficiently performed by coutilizing with CRW in an RPB.

  15. 10 CFR 435.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 3 2013-01-01 2013-01-01 false Water used to achieve energy efficiency. 435.7 Section 435.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL LOW-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise...

  16. 10 CFR 435.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 3 2014-01-01 2014-01-01 false Water used to achieve energy efficiency. 435.7 Section 435.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL LOW-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise...

  17. 10 CFR 435.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 3 2012-01-01 2012-01-01 false Water used to achieve energy efficiency. 435.7 Section 435.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL LOW-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise...

  18. 10 CFR 435.7 - Water used to achieve energy efficiency. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 3 2010-01-01 2010-01-01 false Water used to achieve energy efficiency. 435.7 Section 435.7 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY STANDARDS FOR NEW FEDERAL LOW-RISE RESIDENTIAL BUILDINGS Mandatory Energy Efficiency Standards for Federal Low-Rise...

  19. Constitutive relation for nonlinear response and universality of efficiency at maximum power for tight-coupling heat engines.

    PubMed

    Sheng, Shiqi; Tu, Z C

    2015-02-01

    We present a unified perspective on nonequilibrium heat engines by generalizing nonlinear irreversible thermodynamics. For tight-coupling heat engines, a generic constitutive relation for nonlinear response accurate up to the quadratic order is derived from the stalling condition and the symmetry argument. By applying this generic nonlinear constitutive relation to finite-time thermodynamics, we obtain the necessary and sufficient condition for the universality of efficiency at maximum power, which states that a tight-coupling heat engine takes the universal efficiency at maximum power up to the quadratic order if and only if either the engine symmetrically interacts with two heat reservoirs or the elementary thermal energy flowing through the engine matches the characteristic energy of the engine. Hence we solve the following paradox: On the one hand, the quadratic term in the universal efficiency at maximum power for tight-coupling heat engines turned out to be a consequence of symmetry [Esposito, Lindenberg, and Van den Broeck, Phys. Rev. Lett. 102, 130602 (2009); Sheng and Tu, Phys. Rev. E 89, 012129 (2014)]; On the other hand, typical heat engines such as the Curzon-Ahlborn endoreversible heat engine [Curzon and Ahlborn, Am. J. Phys. 43, 22 (1975)] and the Feynman ratchet [Tu, J. Phys. A 41, 312003 (2008)] recover the universal efficiency at maximum power regardless of any symmetry.

  20. Constitutive relation for nonlinear response and universality of efficiency at maximum power for tight-coupling heat engines.

    PubMed

    Sheng, Shiqi; Tu, Z C

    2015-02-01

    We present a unified perspective on nonequilibrium heat engines by generalizing nonlinear irreversible thermodynamics. For tight-coupling heat engines, a generic constitutive relation for nonlinear response accurate up to the quadratic order is derived from the stalling condition and the symmetry argument. By applying this generic nonlinear constitutive relation to finite-time thermodynamics, we obtain the necessary and sufficient condition for the universality of efficiency at maximum power, which states that a tight-coupling heat engine takes the universal efficiency at maximum power up to the quadratic order if and only if either the engine symmetrically interacts with two heat reservoirs or the elementary thermal energy flowing through the engine matches the characteristic energy of the engine. Hence we solve the following paradox: On the one hand, the quadratic term in the universal efficiency at maximum power for tight-coupling heat engines turned out to be a consequence of symmetry [Esposito, Lindenberg, and Van den Broeck, Phys. Rev. Lett. 102, 130602 (2009); Sheng and Tu, Phys. Rev. E 89, 012129 (2014)]; On the other hand, typical heat engines such as the Curzon-Ahlborn endoreversible heat engine [Curzon and Ahlborn, Am. J. Phys. 43, 22 (1975)] and the Feynman ratchet [Tu, J. Phys. A 41, 312003 (2008)] recover the universal efficiency at maximum power regardless of any symmetry. PMID:25768487

  1. Maximum efficiency of steady-state heat engines at arbitrary power.

    PubMed

    Ryabov, Artem; Holubec, Viktor

    2016-05-01

    We discuss the efficiency of a heat engine operating in a nonequilibrium steady state maintained by two heat reservoirs. Within the general framework of linear irreversible thermodynamics we derive a universal upper bound on the efficiency of the engine operating at arbitrary fixed power. Furthermore, we show that a slight decrease of the power below its maximal value can lead to a significant gain in efficiency. The presented analysis yields the exact expression for this gain and the corresponding upper bound.

  2. Novel benzimidazole derivatives as electron-transporting type host to achieve highly efficient sky-blue phosphorescent organic light-emitting diode (PHOLED) device.

    PubMed

    Huang, Jau-Jiun; Leung, Man-Kit; Chiu, Tien-Lung; Chuang, Ya-Ting; Chou, Pi-Tai; Hung, Yu-Hsiang

    2014-10-17

    The development of benzimidazole substituted biphenyls as electron-transporting hosts for bis[2-(4,6-difluorophenyl)pyridinato-C(2),N](picolinato)iridium(III) is reported. Under the optimized conditions, the organic light-emitting diode (OLED) achieves the maximum current efficiency of 57.2 cd/A, power efficiency of 50.4 lm/W, and external quantum efficiency 25.7%. PMID:25296531

  3. Analysis of the aerodynamic interaction between two plunging plates in tandem at low Reynolds number for maximum propulsive efficiency

    NASA Astrophysics Data System (ADS)

    Ortega-Casanova, Joaquin; Fernandez-Feria, Ramon

    2015-11-01

    The thrust generated by two heaving plates in tandem is analysed for two particular sets of configurations of interest in forward flight: a plunging leading plate with the trailing plate at rest, and the two plates heaving with the same frequency and amplitude, but varying the phase difference. The thrust efficiency of the leading plate is augmented in relation to a single plate heaving with the same frequency and amplitude in most cases. In the first configuration, we characterize the range of nondimensional heaving frequencies and amplitudes of the leading plate for which the stationary trailing plate contributes positively to the global thrust. The maximum global thrust efficiency, reached for an advance ratio slightly less than unity and a reduced frequency close to 5, is about the same as the maximum efficiency for an isolated plate. But for low frequencies the tandem configuration with the trailing plate at rest is more thrust efficient than the isolated plate. In the second configuration, we find that the maximum thrust efficiency is reached for a phase lag of 180o (counterstroking), particularly for an advance ratio unity and a reduced frequency 4.4, and it is practically the same as in the other configuration and that for a single plate. Supported by the Ministerio de Economía y Competitividad of Spain Grant no. DPI2013-40479-P.

  4. 40 CFR 63.55 - Maximum achievable control technology (MACT) determinations for affected sources subject to case...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Requirements for Control Technology Determinations for Major Sources in Accordance With Clean Air Act Sections... quality health and environmental impacts and energy requirements, determines is achievable by affected... and any non-air quality health and environmental impacts and energy requirements, determines...

  5. Optimization Correction Strength Using Contra Bending Technique without Anterior Release Procedure to Achieve Maximum Correction on Severe Adult Idiopathic Scoliosis

    PubMed Central

    Rahyussalim, Ahmad Jabir; Saleh, Ifran; Purnaning, Dyah; Kurniawati, Tri

    2016-01-01

    Adult scoliosis is defined as a spinal deformity in a skeletally mature patient with a Cobb angle of more than 10 degrees in the coronal plain. Posterior-only approach with rod and screw corrective manipulation to add strength of contra bending manipulation has correction achievement similar to that obtained by conventional combined anterior release and posterior approach. It also avoids the complications related to the thoracic approach. We reported a case of 25-year-old male adult idiopathic scoliosis with double curve. It consists of main thoracic curve of 150 degrees and lumbar curve of 89 degrees. His curve underwent direct contra bending posterior approach using rod and screw corrective manipulation technique to achieve optimal correction. After surgery the main thoracic Cobb angle becomes 83 degrees and lumbar Cobb angle becomes 40 degrees, with 5 days length of stay and less than 800 mL blood loss during surgery. There is no complaint at two months after surgery; he has already come back to normal activity with good functional activity. PMID:27064801

  6. Which Tibial Tray Design Achieves Maximum Coverage and Ideal Rotation: Anatomic, Symmetric, or Asymmetric? An MRI-based study.

    PubMed

    Stulberg, S David; Goyal, Nitin

    2015-10-01

    Two goals of tibial tray placement in TKA are to maximize coverage and establish proper rotation. Our purpose was to utilize MRI information obtained as part of PSI planning to determine the impact of tibial tray design on the relationship between coverage and rotation. MR images for 100 consecutive knees were uploaded into PSI software. Preoperative planning software was used to evaluate 3 different tray designs: anatomic, symmetric, and asymmetric. Approximately equally good coverage was achieved with all three trays. However, the anatomic compared to symmetric/asymmetric trays required less malrotation (0.3° vs 3.0/2.4°; P < 0.001), with a higher proportion of cases within 5° of neutral (97% vs 73/77%; P < 0.001). In this study, the anatomic tibia optimized the relationship between coverage and rotation.

  7. [ADVANCE-ON Trial; How to Achieve Maximum Reduction of Mortality in Patients With Type 2 Diabetes].

    PubMed

    Kanorskiĭ, S G

    2015-01-01

    Of 10,261 patients with type 2 diabetes who survived to the end of a randomized ADVANCE trial 83% were included in the ADVANCE-ON project for observation for 6 years. The difference in the level of blood pressure which had been achieved during 4.5 years of within trial treatment with fixed perindopril/indapamide combination quickly vanished but significant decrease of total and cardiovascular mortality in the group of patients treated with this combination for 4.5 years was sustained during 6 years of post-trial follow-up. The results can be related to gradually weakening protective effect of perindopril/indapamide combination on cardiovascular system, and are indicative of the expedience of long-term use of this antihypertensive therapy for maximal lowering of mortality of patients with diabetes. PMID:26164995

  8. A MATLAB toolbox for the efficient estimation of the psychometric function using the updated maximum-likelihood adaptive procedure.

    PubMed

    Shen, Yi; Dai, Wei; Richards, Virginia M

    2015-03-01

    A MATLAB toolbox for the efficient estimation of the threshold, slope, and lapse rate of the psychometric function is described. The toolbox enables the efficient implementation of the updated maximum-likelihood (UML) procedure. The toolbox uses an object-oriented architecture for organizing the experimental variables and computational algorithms, which provides experimenters with flexibility in experimental design and data management. Descriptions of the UML procedure and the UML Toolbox are provided, followed by toolbox use examples. Finally, guidelines and recommendations of parameter configurations are given.

  9. Maximum likelihood algorithm using an efficient scheme for computing sensitivities and parameter confidence intervals

    NASA Technical Reports Server (NTRS)

    Murphy, P. C.; Klein, V.

    1984-01-01

    Improved techniques for estimating airplane stability and control derivatives and their standard errors are presented. A maximum likelihood estimation algorithm is developed which relies on an optimization scheme referred to as a modified Newton-Raphson scheme with estimated sensitivities (MNRES). MNRES determines sensitivities by using slope information from local surface approximations of each output variable in parameter space. The fitted surface allows sensitivity information to be updated at each iteration with a significant reduction in computational effort compared to integrating the analytically-determined sensitivity equations or using a finite difference scheme. An aircraft estimation problem is solved using real flight data to compare MNRES with the commonly used modified Newton-Raphson technique; MNRES is found to be faster and more generally applicable. Parameter standard errors are determined using a random search technique. The confidence intervals obtained are compared with Cramer-Rao lower bounds at the same confidence level. It is observed that the nonlinearity of the cost function is an important factor in the relationship between Cramer-Rao bounds and the error bounds determined by the search technique.

  10. Hybrid Evolutionary Approaches to Maximum Lifetime Routing and Energy Efficiency in Sensor Mesh Networks.

    PubMed

    Rahat, Alma A M; Everson, Richard M; Fieldsend, Jonathan E

    2015-01-01

    Mesh network topologies are becoming increasingly popular in battery-powered wireless sensor networks, primarily because of the extension of network range. However, multihop mesh networks suffer from higher energy costs, and the routing strategy employed directly affects the lifetime of nodes with limited energy resources. Hence when planning routes there are trade-offs to be considered between individual and system-wide battery lifetimes. We present a multiobjective routing optimisation approach using hybrid evolutionary algorithms to approximate the optimal trade-off between the minimum lifetime and the average lifetime of nodes in the network. In order to accomplish this combinatorial optimisation rapidly, our approach prunes the search space using k-shortest path pruning and a graph reduction method that finds candidate routes promoting long minimum lifetimes. When arbitrarily many routes from a node to the base station are permitted, optimal routes may be found as the solution to a well-known linear program. We present an evolutionary algorithm that finds good routes when each node is allowed only a small number of paths to the base station. On a real network deployed in the Victoria & Albert Museum, London, these solutions, using only three paths per node, are able to achieve minimum lifetimes of over 99% of the optimum linear program solution's time to first sensor battery failure. PMID:25950392

  11. Hybrid Evolutionary Approaches to Maximum Lifetime Routing and Energy Efficiency in Sensor Mesh Networks.

    PubMed

    Rahat, Alma A M; Everson, Richard M; Fieldsend, Jonathan E

    2015-01-01

    Mesh network topologies are becoming increasingly popular in battery-powered wireless sensor networks, primarily because of the extension of network range. However, multihop mesh networks suffer from higher energy costs, and the routing strategy employed directly affects the lifetime of nodes with limited energy resources. Hence when planning routes there are trade-offs to be considered between individual and system-wide battery lifetimes. We present a multiobjective routing optimisation approach using hybrid evolutionary algorithms to approximate the optimal trade-off between the minimum lifetime and the average lifetime of nodes in the network. In order to accomplish this combinatorial optimisation rapidly, our approach prunes the search space using k-shortest path pruning and a graph reduction method that finds candidate routes promoting long minimum lifetimes. When arbitrarily many routes from a node to the base station are permitted, optimal routes may be found as the solution to a well-known linear program. We present an evolutionary algorithm that finds good routes when each node is allowed only a small number of paths to the base station. On a real network deployed in the Victoria & Albert Museum, London, these solutions, using only three paths per node, are able to achieve minimum lifetimes of over 99% of the optimum linear program solution's time to first sensor battery failure.

  12. Maximum Flow Efficiency in an Anabranching River, Magela Creek, Northern Australia

    NASA Astrophysics Data System (ADS)

    Jansen, J. D.; Nanson, G. C.

    2002-12-01

    In this field- and laboratory-based study, we demonstrate that the development of anabranching channels in some rivers increases the conveyance of sediment and water, compared with a single channel at the same flow discharge. That is, under certain conditions, anabranching channels exhibit greater sediment transporting capacity per unit available stream power. Anabranching is a globally widespread river pattern noted in diverse physiographic, hydrologic and sedimentologic environments, and recent efforts have sought to unravel controls on their origin and maintenance. It is widely held that most rivers form a single-channel in order to minimise boundary roughness while conveying water and sediment, but do all rivers show a tendency to develop a single channel? And if so, what factors lead to long-term anabranching? The observation that anabranching commonly develops in environments where water and sediment conveyance is maintained with little or no recourse to increasing energy slope prompted the hypothesis that rivers may adopt a multiple channel pattern in order to optimise their efficiency where they cannot otherwise increase slope. It is reasoned that development of a system of multiple channels reduces total flow width and raises mean flow depth, thereby maximising sediment transport per unit area of the channel bed and maintaining or enhancing water and sediment throughput. In testing the hypothesis we present: (1) results of a field experiment in which hydraulic variables and bedload discharge are measured and compared for single-channel versus multichannel reaches of the same river (Magela Creek, northern Australia); (2) comparison of these field results with bedload transport modelling via well known bedload equations; and (3) results of an experimental flume study comparing hydraulic variables and sediment flux in single-channel versus divided flow. Magela Creek is representative of several anabranching systems draining the Alligators Rivers Region of

  13. Sex preselection: high-speed flow cytometric sorting of X and Y sperm for maximum efficiency.

    PubMed

    Johnson, L A; Welch, G R

    1999-12-01

    Sex preselection that is based on flow-cytometric measurement of sperm DNA content to enable sorting of X- from Y-chromosome-bearing sperm has proven reproducible at various locations and with many species at greater than 90% purity. Offspring of the predetermined sex in both domestic animals and human beings have been born using this technology since its introduction in 1989. The method involves treating sperm with the fluorescent dye, Hoechst 33342, which binds to the DNA and then sorting them into X- and Y-bearing-sperm populations with a flow cytometer/cell sorter modified specifically for sperm. Sexed sperm are then used with differing semen delivery routes such as intra-uterine, intra-tubal, artificial insemination (deep-uterine and cervical), in vitro fertilization and embryo transfer, and intra-cytoplasmic sperm injection (ICSI). Offspring produced at all locations using the technology have been morphologically normal and reproductively capable in succeeding generations. With the advent of high-speed cell sorting technology and improved efficiency of sorting by a new sperm orienting nozzle, the efficiency of sexed sperm production is significantly enhanced. This paper describes development of the these technological improvements in the Beltsville Sexing Technology that has brought sexed sperm to a new level of application. Under typical conditions the high-speed sperm sorter with the orienting nozzle (HiSON) results in purities of 90% of X- and Y-bearing sperm at 6 million sperm per h for each population. Taken to its highest performance level, the HiSON has produced X-bearing-sperm populations at 85 to 90% purity in the production of up to 11 million X-bearing-sperm per h of sorting. In addition if one accepts a lower purity (75 to 80%) of X, nearly 20 million sperm can be sorted per h. The latter represents a 30 to 60-fold improvement over the 1989 sorting technology using rabbit sperm. It is anticipated that with instrument refinements the production

  14. A general strategy to achieve ultra-high gene transfection efficiency using lipid-nanoparticle composites.

    PubMed

    Vankayala, Raviraj; Chiang, Chi-Shiun; Chao, Jui-I; Yuan, Chiun-Jye; Lin, Shyr-Yeu; Hwang, Kuo Chu

    2014-09-01

    Gene therapy provides a new hope for previously "incurable" diseases. Low gene transfection efficiency, however, is the bottle-neck to the success of gene therapy. It is very challenging to develop non-viral nanocarriers to achieve ultra-high gene transfection efficiencies. Herein, we report a novel design of "tight binding-but-detachable" lipid-nanoparticle composite to achieve ultrahigh gene transfection efficiencies of 60∼82%, approaching the best value (∼90%) obtained using viral vectors. We show that Fe@CNPs nanoparticles coated with LP-2000 lipid molecules can be used as gene carriers to achieve ultra-high (60-80%) gene transfection efficiencies in HeLa, U-87MG, and TRAMP-C1 cells. In contrast, Fe@CNPs having surface-covalently bound N,N,N-trimethyl-N-2-methacryloxyethyl ammonium chloride (TMAEA) oligomers can only achieve low (23-28%) gene transfection efficiencies. Similarly ultrahigh gene transfection/expression was also observed in zebrafish model using lipid-coated Fe@CNPs as gene carriers. Evidences for tight binding and detachability of DNA from lipid-nanoparticle nanocarriers will be presented. PMID:24973297

  15. A general strategy to achieve ultra-high gene transfection efficiency using lipid-nanoparticle composites.

    PubMed

    Vankayala, Raviraj; Chiang, Chi-Shiun; Chao, Jui-I; Yuan, Chiun-Jye; Lin, Shyr-Yeu; Hwang, Kuo Chu

    2014-09-01

    Gene therapy provides a new hope for previously "incurable" diseases. Low gene transfection efficiency, however, is the bottle-neck to the success of gene therapy. It is very challenging to develop non-viral nanocarriers to achieve ultra-high gene transfection efficiencies. Herein, we report a novel design of "tight binding-but-detachable" lipid-nanoparticle composite to achieve ultrahigh gene transfection efficiencies of 60∼82%, approaching the best value (∼90%) obtained using viral vectors. We show that Fe@CNPs nanoparticles coated with LP-2000 lipid molecules can be used as gene carriers to achieve ultra-high (60-80%) gene transfection efficiencies in HeLa, U-87MG, and TRAMP-C1 cells. In contrast, Fe@CNPs having surface-covalently bound N,N,N-trimethyl-N-2-methacryloxyethyl ammonium chloride (TMAEA) oligomers can only achieve low (23-28%) gene transfection efficiencies. Similarly ultrahigh gene transfection/expression was also observed in zebrafish model using lipid-coated Fe@CNPs as gene carriers. Evidences for tight binding and detachability of DNA from lipid-nanoparticle nanocarriers will be presented.

  16. Hydraulic limits on maximum plant transpiration and the emergence of the safety-efficiency trade-off.

    PubMed

    Manzoni, Stefano; Vico, Giulia; Katul, Gabriel; Palmroth, Sari; Jackson, Robert B; Porporato, Amilcare

    2013-04-01

    Soil and plant hydraulics constrain ecosystem productivity by setting physical limits to water transport and hence carbon uptake by leaves. While more negative xylem water potentials provide a larger driving force for water transport, they also cause cavitation that limits hydraulic conductivity. An optimum balance between driving force and cavitation occurs at intermediate water potentials, thus defining the maximum transpiration rate the xylem can sustain (denoted as E(max)). The presence of this maximum raises the question as to whether plants regulate transpiration through stomata to function near E(max). To address this question, we calculated E(max) across plant functional types and climates using a hydraulic model and a global database of plant hydraulic traits. The predicted E(max) compared well with measured peak transpiration across plant sizes and growth conditions (R = 0.86, P < 0.001) and was relatively conserved among plant types (for a given plant size), while increasing across climates following the atmospheric evaporative demand. The fact that E(max) was roughly conserved across plant types and scales with the product of xylem saturated conductivity and water potential at 50% cavitation was used here to explain the safety-efficiency trade-off in plant xylem. Stomatal conductance allows maximum transpiration rates despite partial cavitation in the xylem thereby suggesting coordination between stomatal regulation and xylem hydraulic characteristics. PMID:23356378

  17. Hydraulic limits on maximum plant transpiration and the emergence of the safety-efficiency trade-off.

    PubMed

    Manzoni, Stefano; Vico, Giulia; Katul, Gabriel; Palmroth, Sari; Jackson, Robert B; Porporato, Amilcare

    2013-04-01

    Soil and plant hydraulics constrain ecosystem productivity by setting physical limits to water transport and hence carbon uptake by leaves. While more negative xylem water potentials provide a larger driving force for water transport, they also cause cavitation that limits hydraulic conductivity. An optimum balance between driving force and cavitation occurs at intermediate water potentials, thus defining the maximum transpiration rate the xylem can sustain (denoted as E(max)). The presence of this maximum raises the question as to whether plants regulate transpiration through stomata to function near E(max). To address this question, we calculated E(max) across plant functional types and climates using a hydraulic model and a global database of plant hydraulic traits. The predicted E(max) compared well with measured peak transpiration across plant sizes and growth conditions (R = 0.86, P < 0.001) and was relatively conserved among plant types (for a given plant size), while increasing across climates following the atmospheric evaporative demand. The fact that E(max) was roughly conserved across plant types and scales with the product of xylem saturated conductivity and water potential at 50% cavitation was used here to explain the safety-efficiency trade-off in plant xylem. Stomatal conductance allows maximum transpiration rates despite partial cavitation in the xylem thereby suggesting coordination between stomatal regulation and xylem hydraulic characteristics.

  18. Controlling surface enrichment in polymeric hole extraction layers to achieve high-efficiency organic photovoltaic cells.

    PubMed

    Kim, Dong-Hun; Lim, Kyung-Geun; Park, Jong Hyeok; Lee, Tae-Woo

    2012-10-01

    Hole extraction in organic photovoltaic cells (OPVs) can be modulated by a surface-enriched layer formed on top of the conducting polymer-based hole extraction layer (HEL). This tunes the surface work function of the HEL to better align with the ionization potential of the polymeric photoactive layer. Results show noticeable improvement in device power conversion efficiencies (PCEs) in OPVs. We achieved a 6.1 % PCE from the OPV by optimizing the surface-enriched layer.

  19. Device engineering of perovskite solar cells to achieve near ideal efficiency

    SciTech Connect

    Agarwal, Sumanshu E-mail: prnair@ee.iitb.ac.in; Nair, Pradeep R. E-mail: prnair@ee.iitb.ac.in

    2015-09-21

    Despite the exciting recent research on perovskite based solar cells, the design space for further optimization and the practical limits of efficiency are not well known in the community. In this letter, we address these aspects through theoretical calculations and detailed numerical simulations. Here, we first provide the detailed balance limit efficiency in the presence of radiative and Auger recombination. Then, using coupled optical and carrier transport simulations, we identify the physical mechanisms that contribute towards bias dependent carrier collection, and hence low fill factors of current perovskite based solar cells. Our detailed simulations indicate that it is indeed possible to achieve efficiencies and fill factors greater than 25% and 85%, respectively, with near ideal super-position characteristics even in the presence of Auger recombination.

  20. Tuning charge balance in PHOLEDs with ambipolar host materials to achieve high efficiency

    SciTech Connect

    Padmaperuma, Asanga B.; Koech, Phillip K.; Cosimbescu, Lelia; Polikarpov, Evgueni; Swensen, James S.; Chopra, Neetu; So, Franky; Sapochak, Linda S.; Gaspar, Daniel J.

    2009-08-27

    The efficiency and stability of blue organic light emitting devices (OLEDs) continue to be a primary roadblock to developing organic solid state white lighting. For OLEDs to meet the high power conversion efficiency goal, they will require both close to 100% internal quantum efficiency and low operating voltage in a white light emitting device.1 It is generally accepted that such high quantum efficiency, can only be achieved with the use of organometallic phosphor doped OLEDs. Blue OLEDs are particularly important for solid state lighting. The simplest (and therefore likely the lowest cost) method of generating white light is to down convert part of the emission from a blue light source with a system of external phosphors.2 A second method of generating white light requires the superposition of the light from red, green and blue OLEDs in the correct ratio. Either of these two methods (and indeed any method of generating white light with a high color rendering index) critically depends on a high efficiency blue light component.3 A simple OLED generally consists of a hole-injecting anode, a preferentially hole transporting organic layer (HTL), an emissive layer that contains the recombination zone and ideally transports both holes and electrons, a preferentially electron-transporting layer (ETL) and an electron-injecting cathode. Color in state-of-the-art OLEDs is generated by an organometallic phosphor incorporated by co-sublimation into the emissive layer (EML).4 New materials functioning as hosts, emitters, charge transporting, and charge blocking layers have been developed along with device architectures leading to electrophosphorescent based OLEDs with high quantum efficiencies near the theoretical limit. However, the layers added to the device architecture to enable high quantum efficiencies lead to higher operating voltages and correspondingly lower power efficiencies. Achievement of target luminance power efficiencies will require new strategies for lowering

  1. Energy efficiency enhancements for semiconductors, communications, sensors and software achieved in cool silicon cluster project

    NASA Astrophysics Data System (ADS)

    Ellinger, Frank; Mikolajick, Thomas; Fettweis, Gerhard; Hentschel, Dieter; Kolodinski, Sabine; Warnecke, Helmut; Reppe, Thomas; Tzschoppe, Christoph; Dohl, Jan; Carta, Corrado; Fritsche, David; Tretter, Gregor; Wiatr, Maciej; Detlef Kronholz, Stefan; Mikalo, Ricardo Pablo; Heinrich, Harald; Paulo, Robert; Wolf, Robert; Hübner, Johannes; Waltsgott, Johannes; Meißner, Klaus; Richter, Robert; Michler, Oliver; Bausinger, Markus; Mehlich, Heiko; Hahmann, Martin; Möller, Henning; Wiemer, Maik; Holland, Hans-Jürgen; Gärtner, Roberto; Schubert, Stefan; Richter, Alexander; Strobel, Axel; Fehske, Albrecht; Cech, Sebastian; Aßmann, Uwe; Pawlak, Andreas; Schröter, Michael; Finger, Wolfgang; Schumann, Stefan; Höppner, Sebastian; Walter, Dennis; Eisenreich, Holger; Schüffny, René

    2013-07-01

    An overview about the German cluster project Cool Silicon aiming at increasing the energy efficiency for semiconductors, communications, sensors and software is presented. Examples for achievements are: 1000 times reduced gate leakage in transistors using high-fc (HKMG) materials compared to conventional poly-gate (SiON) devices at the same technology node; 700 V transistors integrated in standard 0.35 μm CMOS; solar cell efficiencies above 19% at < 200 W/m2 irradiation; 0.99 power factor, 87% efficiency and 0.088 distortion factor for dc supplies; 1 ns synchronization resolution via Ethernet; database accelerators allowing 85% energy savings for servers; adaptive software yielding energy reduction of 73% for e-Commerce applications; processors and corresponding data links with 40% and 70% energy savings, respectively, by adaption of clock frequency and supply voltage in less than 20 ns; clock generator chip with tunable frequency from 83-666 MHz and 0.62-1.6 mW dc power; 90 Gb/s on-chip link over 6 mm and efficiency of 174 fJ/mm; dynamic biasing system doubling efficiency in power amplifiers; 60 GHz BiCMOS frontends with dc power to bandwidth ratio of 0.17 mW/MHz; driver assistance systems reducing energy consumption by 10% in cars Contribution to the Topical Issue “International Semiconductor Conference Dresden-Grenoble - ISCDG 2012”, Edited by Gérard Ghibaudo, Francis Balestra and Simon Deleonibus.

  2. Achievement-Relevant Personality: Relations with the Big Five and Validation of an Efficient Instrument.

    PubMed

    Briley, Daniel A; Domiteaux, Matthew; Tucker-Drob, Elliot M

    2014-05-01

    Many achievement-relevant personality measures (APMs) have been developed, but the interrelations among APMs or associations with the broader personality landscape are not well-known. In Study 1, 214 participants were measured on 36 APMs and a measure of the Big Five. Factor analytic results supported the convergent and discriminant validity of five latent dimensions: performance, mastery, self-doubt, effort, and intellectual investment. Conscientiousness, neuroticism, and openness to experience had the most consistent associations with APMs. We constructed a more efficient scale- the Multidimensional Achievement-Relevant Personality Scale (MAPS). In Study 2, we replicated the factor structure and external correlates of the MAPS in a sample of 359 individuals. Finally, we validated the MAPS with four indicators of academic performance and demonstrated incremental validity.

  3. Achievement-Relevant Personality: Relations with the Big Five and Validation of an Efficient Instrument

    PubMed Central

    Briley, Daniel A.; Domiteaux, Matthew; Tucker-Drob, Elliot M.

    2014-01-01

    Many achievement-relevant personality measures (APMs) have been developed, but the interrelations among APMs or associations with the broader personality landscape are not well-known. In Study 1, 214 participants were measured on 36 APMs and a measure of the Big Five. Factor analytic results supported the convergent and discriminant validity of five latent dimensions: performance, mastery, self-doubt, effort, and intellectual investment. Conscientiousness, neuroticism, and openness to experience had the most consistent associations with APMs. We constructed a more efficient scale– the Multidimensional Achievement-Relevant Personality Scale (MAPS). In Study 2, we replicated the factor structure and external correlates of the MAPS in a sample of 359 individuals. Finally, we validated the MAPS with four indicators of academic performance and demonstrated incremental validity. PMID:24839374

  4. Equivalence of ideal, isothermal-adiabatic, and complex cycles of gas turbine power plants and determination of the maximum efficiency of their operation

    NASA Astrophysics Data System (ADS)

    Ivanov, V. A.

    2010-12-01

    The possibility of ensuring equivalence in operation and efficiency of real cycles with intermediate cooling (heating) and isothermal-adiabatic compressions (expansion) in ideal simple cycles formed on the T- S diagrams in the second stage of real cycles. The possibility of using the equivalence of cycles for determining the maximum efficiency of operation of real cycles is demonstrated.

  5. FEMP's O & M Best Practices Guide: A Guide to Achieving Operational Efficiency

    SciTech Connect

    Sullivan, Gregory P. ); Melendez, Aldo P. ); Pugh, Ray )

    2002-10-01

    FEMP's O & M Best Practices Guide (O & M BPG) highlights O & M programs targeting energy efficiency that are estimated to save between 5% and 20% on energy bills without a significant capital investment. Depending on the Federal site, these savings can represent thousands to hundreds-of-thousands of dollars each year, and many can be achieved with minimal cash outlays. In addition to energy/resource savings, a well-run O & M program will (1)increase the safety of all staff because properly maintained equipment is safer equipment; (2)ensure the comfort, health and safety of building occupants through properly functioning equipment providing a healthy indoor environment; (3)confirm the design life expectancy of equipment is achieved; and (4)facilitate the compliance with Federal legislation such as the Clean Air Act and the Clean Water Act. The focus of this guide is to provide the Federal O & M/Energy manager and practitioner with information and actions aimed at achieving these savings and benefits. The O & M BPG was developed under the direction of the Department of Energy's Federal Energy Management Program (FEMP).

  6. Alternative Formats to Achieve More Efficient Energy Codes for Commercial Buildings

    SciTech Connect

    Conover, David R.; Rosenberg, Michael I.; Halverson, Mark A.; Taylor, Zachary T.; Makela, Eric J.

    2013-01-26

    This paper identifies and examines several formats or structures that could be used to create the next generation of more efficient energy codes and standards for commercial buildings. Pacific Northwest National Laboratory (PNNL) is funded by the U.S. Department of Energy’s Building Energy Codes Program (BECP) to provide technical support to the development of ANSI/ASHRAE/IES Standard 90.1. While the majority of PNNL’s ASHRAE Standard 90.1 support focuses on developing and evaluating new requirements, a portion of its work involves consideration of the format of energy standards. In its current working plan, the ASHRAE 90.1 committee has approved an energy goal of 50% improvement in Standard 90.1-2013 relative to Standard 90.1-2004, and will likely be considering higher improvement targets for future versions of the standard. To cost-effectively achieve the 50% goal in manner that can gain stakeholder consensus, formats other than prescriptive must be considered. Alternative formats that include reducing the reliance on prescriptive requirements may make it easier to achieve these aggressive efficiency levels in new codes and standards. The focus on energy code and standard formats is meant to explore approaches to presenting the criteria that will foster compliance, enhance verification, and stimulate innovation while saving energy in buildings. New formats may also make it easier for building designers and owners to design and build the levels of efficiency called for in the new codes and standards. This paper examines a number of potential formats and structures, including prescriptive, performance-based (with sub-formats of performance equivalency and performance targets), capacity constraint-based, and outcome-based. The paper also discusses the pros and cons of each format from the viewpoint of code users and of code enforcers.

  7. Achieving Extreme Utilization of Excitons by an Efficient Sandwich-Type Emissive Layer Architecture for Reduced Efficiency Roll-Off and Improved Operational Stability in Organic Light-Emitting Diodes.

    PubMed

    Wu, Zhongbin; Sun, Ning; Zhu, Liping; Sun, Hengda; Wang, Jiaxiu; Yang, Dezhi; Qiao, Xianfeng; Chen, Jiangshan; Alshehri, Saad M; Ahamad, Tansir; Ma, Dongge

    2016-02-10

    It has been demonstrated that the efficiency roll-off is generally caused by the accumulation of excitons or charge carriers, which is intimately related to the emissive layer (EML) architecture in organic light-emitting diodes (OLEDs). In this article, an efficient sandwich-type EML structure with a mixed-host EML sandwiched between two single-host EMLs was designed to eliminate this accumulation, thus simultaneously achieving high efficiency, low efficiency roll-off and good operational stability in the resulting OLEDs. The devices show excellent electroluminescence performances, realizing a maximum external quantum efficiency (EQE) of 24.6% with a maximum power efficiency of 105.6 lm W(-1) and a maximum current efficiency of 93.5 cd A(-1). At the high brightness of 5,000 cd m(-2), they still remain as high as 23.3%, 71.1 lm W(-1), and 88.3 cd A(-1), respectively. And, the device lifetime is up to 2000 h at initial luminance of 1000 cd m(-2), which is significantly higher than that of compared devices with conventional EML structures. The improvement mechanism is systematically studied by the dependence of the exciton distribution in EML and the exciton quenching processes. It can be seen that the utilization of the efficient sandwich-type EML broadens the recombination zone width, thus greatly reducing the exciton quenching and increasing the probability of the exciton recombination. It is believed that the design concept provides a new avenue for us to achieve high-performance OLEDs.

  8. Efficient Parameter Estimation of Generalizable Coarse-Grained Protein Force Fields Using Contrastive Divergence: A Maximum Likelihood Approach

    PubMed Central

    2013-01-01

    Maximum Likelihood (ML) optimization schemes are widely used for parameter inference. They maximize the likelihood of some experimentally observed data, with respect to the model parameters iteratively, following the gradient of the logarithm of the likelihood. Here, we employ a ML inference scheme to infer a generalizable, physics-based coarse-grained protein model (which includes Go̅-like biasing terms to stabilize secondary structure elements in room-temperature simulations), using native conformations of a training set of proteins as the observed data. Contrastive divergence, a novel statistical machine learning technique, is used to efficiently approximate the direction of the gradient ascent, which enables the use of a large training set of proteins. Unlike previous work, the generalizability of the protein model allows the folding of peptides and a protein (protein G) which are not part of the training set. We compare the same force field with different van der Waals (vdW) potential forms: a hard cutoff model, and a Lennard-Jones (LJ) potential with vdW parameters inferred or adopted from the CHARMM or AMBER force fields. Simulations of peptides and protein G show that the LJ model with inferred parameters outperforms the hard cutoff potential, which is consistent with previous observations. Simulations using the LJ potential with inferred vdW parameters also outperforms the protein models with adopted vdW parameter values, demonstrating that model parameters generally cannot be used with force fields with different energy functions. The software is available at https://sites.google.com/site/crankite/. PMID:24683370

  9. Optimizing Bi2O3 and TiO2 to achieve the maximum non-linear electrical property of ZnO low voltage varistor

    PubMed Central

    2013-01-01

    Background In fabrication of ZnO-based low voltage varistor, Bi2O3 and TiO2 have been used as former and grain growth enhancer factors respectively. Therefore, the molar ratio of the factors is quit important in the fabrication. In this paper, modeling and optimization of Bi2O3 and TiO2 was carried out by response surface methodology to achieve maximized electrical properties. The fabrication was planned by central composite design using two variables and one response. To obtain actual responses, the design was performed in laboratory by the conventional methods of ceramics fabrication. The actual responses were fitted into a valid second order algebraic polynomial equation. Then the quadratic model was suggested by response surface methodology. The model was validated by analysis of variance which provided several evidences such as high F-value (153.6), very low P-value (<0.0001), adjusted R-squared (0.985) and predicted R-squared (0.947). Moreover, the lack of fit was not significant which means the model was significant. Results The model tracked the optimum of the additives in the design by using three dimension surface plots. In the optimum condition, the molars ratio of Bi2O3 and TiO2 were obtained in a surface area around 1.25 point that maximized the nonlinear coefficient around 20 point. Moreover, the model predicted the optimum amount of the additives in desirable condition. In this case, the condition included minimum standard error (0.35) and maximum nonlinearity (20.03), while molar ratio of Bi2O3 (1.24 mol%) and TiO2 (1.27 mol%) was in range. The condition as a solution was tested by further experiments for confirmation. As the experimental results showed, the obtained value of the non-linearity, 21.6, was quite close to the predicted model. Conclusion Response surface methodology has been successful for modeling and optimizing the additives such as Bi2O3 and TiO2 of ZnO-based low voltage varistor to achieve maximized non-linearity properties. PMID

  10. Efficient Full Information Maximum Likelihood Estimation for Multidimensional IRT Models. Research Report. ETS RR-09-03

    ERIC Educational Resources Information Center

    Rijmen, Frank

    2009-01-01

    Maximum marginal likelihood estimation of multidimensional item response theory (IRT) models has been hampered by the calculation of the multidimensional integral over the ability distribution. However, the researcher often has a specific hypothesis about the conditional (in)dependence relations among the latent variables. Exploiting these…

  11. Achieving Highly Efficient, Selective, and Stable CO2 Reduction on Nitrogen-Doped Carbon Nanotubes.

    PubMed

    Wu, Jingjie; Yadav, Ram Manohar; Liu, Mingjie; Sharma, Pranav P; Tiwary, Chandra Sekhar; Ma, Lulu; Zou, Xiaolong; Zhou, Xiao-Dong; Yakobson, Boris I; Lou, Jun; Ajayan, Pulickel M

    2015-05-26

    The challenge in the electrosynthesis of fuels from CO2 is to achieve durable and active performance with cost-effective catalysts. Here, we report that carbon nanotubes (CNTs), doped with nitrogen to form resident electron-rich defects, can act as highly efficient and, more importantly, stable catalysts for the conversion of CO2 to CO. The unprecedented overpotential (-0.18 V) and selectivity (80%) observed on nitrogen-doped CNTs (NCNTs) are attributed to their unique features to facilitate the reaction, including (i) high electrical conductivity, (ii) preferable catalytic sites (pyridinic N defects), and (iii) low free energy for CO2 activation and high barrier for hydrogen evolution. Indeed, DFT calculations show a low free energy barrier for the potential-limiting step to form key intermediate COOH as well as strong binding energy of adsorbed COOH and weak binding energy for the adsorbed CO. The highest selective site toward CO production is pyridinic N, and the NCNT-based electrodes exhibit no degradation over 10 h of continuous operation, suggesting the structural stability of the electrode.

  12. Limits on Achievable Dimensional and Photon Efficiencies with Intensity-Modulation and Photon-Counting Due to Non-Ideal Photon-Counter Behavior

    NASA Technical Reports Server (NTRS)

    Moision, Bruce; Erkmen, Baris I.; Farr, William; Dolinar, Samuel J.; Birnbaum, Kevin M.

    2012-01-01

    An ideal intensity-modulated photon-counting channel can achieve unbounded photon information efficiencies (PIEs). However, a number of limitations of a physical system limit the practically achievable PIE. In this paper, we discuss several of these limitations and illustrate their impact on the channel. We show that, for the Poisson channel, noise does not strictly bound PIE, although there is an effective limit, as the dimensional information efficiency goes as e[overline] e PIE beyond a threshold PIE. Since the Holevo limit is bounded in the presence of noise, this illustrates that the Poisson approximation is invalid at large PIE for any number of noise modes. We show that a finite transmitter extinction ratio bounds the achievable PIE to a maximum that is logarithmic in the extinction ratio. We show how detector jitter limits the ability to mitigate noise in the PPM signaling framework. We illustrate a method to model detector blocking when the number of detectors is large, and illustrate mitigation of blocking with spatial spreading and altering. Finally, we illustrate the design of a high photon efficiency system using state-of-the-art photo-detectors and taking all these effects into account.

  13. Study for the optimization of a transport aircraft wing for maximum fuel efficiency. Volume 1: Methodology, criteria, aeroelastic model definition and results

    NASA Technical Reports Server (NTRS)

    Radovcich, N. A.; Dreim, D.; Okeefe, D. A.; Linner, L.; Pathak, S. K.; Reaser, J. S.; Richardson, D.; Sweers, J.; Conner, F.

    1985-01-01

    Work performed in the design of a transport aircraft wing for maximum fuel efficiency is documented with emphasis on design criteria, design methodology, and three design configurations. The design database includes complete finite element model description, sizing data, geometry data, loads data, and inertial data. A design process which satisfies the economics and practical aspects of a real design is illustrated. The cooperative study relationship between the contractor and NASA during the course of the contract is also discussed.

  14. Maximum Jailbreak

    NASA Astrophysics Data System (ADS)

    Singleton, B.

    First formulated one hundred and fifty years ago by the heretical scholar Nikolai Federov, the doctrine of cosmism begins with an absolute refusal to treat the most basic factors conditioning life on Earth ­ gravity and death ­ as necessary constraints on action. As manifest through the intoxicated cheers of its early advocates that humans should storm the heavens and conquer death, cosmism's foundational gesture was to conceive of the earth as a trap. Its duty was therefore to understand the duty of philosophy, economics and design to be the creation of means to escape it. This could be regarded as a jailbreak at the maximum possible scale, a heist in which the human species could steal itself from the vault of the Earth. After several decades of relative disinterest new space ventures are inspiring scientific, technological and popular imaginations, this essay explores what kind of cosmism might be constructed today. In this paper cosmism's position as a means of escape is both reviewed and evaluated by reflecting on the potential of technology that actually can help us achieve its aims and also through the lens and state-ofthe-art philosophy of accelerationism, which seeks to outrun modern tropes by intensifying them.

  15. Expert Meeting Report: Achieving the Best Installed Performance from High-Efficiency Residential Gas Furnaces

    SciTech Connect

    Brand, L.

    2012-03-01

    This report describes a Building America expert meeting hosted on July 28, 2011, by the Partnership for Advanced Residential Retrofit team. The purpose of this meeting was to identify installation practices that provide the best installed efficiency for residential gas furnaces, explain how AFUE and field efficiency can differ, and investigate the impact of installation practices on the efficiency and long-term durability of the furnace.

  16. Expert Meeting Report: Achieving the Best Installed Performance from High-Efficiency Residential Gas Furnaces

    SciTech Connect

    Brand, Larry

    2012-03-01

    This report describes a Building America expert meeting hosted on July 28, 2011, by the Partnership for Advanced Residential Retrofit (PARR) team. The purpose of this meeting was to identify installation practices that provide the best installed efficiency for residential gas furnaces, explain how AFUE and field efficiency can differ, and investigate the impact of installation practices on the efficiency and long-term durability of the furnace.

  17. On enforcing maximum principles and achieving element-wise species balance for advection-diffusion-reaction equations under the finite element method

    NASA Astrophysics Data System (ADS)

    Mudunuru, M. K.; Nakshatrala, K. B.

    2016-01-01

    We present a robust computational framework for advective-diffusive-reactive systems that satisfies maximum principles, the non-negative constraint, and element-wise species balance property. The proposed methodology is valid on general computational grids, can handle heterogeneous anisotropic media, and provides accurate numerical solutions even for very high Péclet numbers. The significant contribution of this paper is to incorporate advection (which makes the spatial part of the differential operator non-self-adjoint) into the non-negative computational framework, and overcome numerical challenges associated with advection. We employ low-order mixed finite element formulations based on least-squares formalism, and enforce explicit constraints on the discrete problem to meet the desired properties. The resulting constrained discrete problem belongs to convex quadratic programming for which a unique solution exists. Maximum principles and the non-negative constraint give rise to bound constraints while element-wise species balance gives rise to equality constraints. The resulting convex quadratic programming problems are solved using an interior-point algorithm. Several numerical results pertaining to advection-dominated problems are presented to illustrate the robustness, convergence, and the overall performance of the proposed computational framework.

  18. High-Efficiency Rooftop Air Conditioners: Innovative Procurement to Achieve Advances in Technology

    SciTech Connect

    Hollomon, Brad

    2003-08-01

    The U.S. Department of Energy, Defense Logistics Agency, and Pacific Northwest National Laboratory recently conducted a technology procurement to increase the availability of energy-efficient, packaged unitary ''rooftop'' air conditioners. The procurement encouraged air conditioner manufacturers to produce equipment that exceeded US energy efficiency standards by at least 25% at a lower life-cycle cost. An outgrowth of the project, a web-based cost estimator tool is now available to help consumers determine the cost-effectiveness of purchasing energy-efficient air conditioners based on climate conditions and other factors at their own locations.

  19. The Effect of Curriculum for Developing Efficient Studying Skills on Academic Achievements and Studying Skills of Learners

    ERIC Educational Resources Information Center

    Demir, Semra; Kilinc, Mehmet; Dogan, Ali

    2012-01-01

    Purpose of this study is to examine the effect of "Development of Efficient Studying Skills Curriculum" on academic achievements and studying skills of 7th grade primary school students. In this study, pre-test post-test from experiment models and semi-experimental model with control group were preferred. The reason for the preference is…

  20. O&M Best Practices - A Guide to Achieving Operational Efficiency (Release 2.0)

    SciTech Connect

    Sullivan, Gregory P.; Pugh, Ray; Melendez, Aldo P.; Hunt, W. D.

    2004-07-31

    This guide, sponsored by DOE's Federal Energy Management Program, highlights operations and maintenance (O&M) programs targeting energy efficiency that are estimated to save 5% to 20% on energy bills without a significant capital investment. The purpose of this guide is to provide the federal O&M energy manager and practitioner with useful information about O&M management, technologies, energy efficiency and cost-reduction approaches.

  1. Swine herds achieve high performance by culling low lifetime efficiency sows in early parity.

    PubMed

    Takanashi, Ariko; McTaggart, Iain; Koketsu, Yuzo

    2011-11-01

    Sow lifetime performance and by-parity performance were analyzed using a 3 by 3 factorial design, comprising 3 herd productivity groups and 3 sow efficiency groups. Data was obtained from 101 Japanese herds, totaling 173,526 parity records of 34,929 sows, for the years 2001 to 2006. Sows were categorized into 3 groups based on the lower and upper 25th percentiles of the annualized lifetime pigs born alive: low lifetime efficiency sows (LE sows), intermediate lifetime efficiency sows or high lifetime efficiency sows. Herds were grouped on the basis of the upper and lower 25th percentiles of pigs weaned per mated female per year, averaged over 6 years: high-, intermediate- or low-performing herds. Mixed-effects models were used for comparisons. LE sows in high-performing herds had 57.8 fewer lifetime nonproductive days and 0.5 earlier parity at removal than those in low-performing herds (P<0.05). The number of pigs born alive of LE sows continuously decreased from parity 1 to 5, whereas those of high lifetime efficiency sows gradually increased from parity 1 to 4 before decreasing up to parity ≥ 6 (P<0.05). In conclusion, the LE sows have a performance pattern of decreasing number of pigs born alive across parity. The present study also indicates that high-performing herds culled potential LE sows earlier than the other herds.

  2. Student Achievement and Efficiency in Missouri Schools and the No Child Left Behind Act

    ERIC Educational Resources Information Center

    Primont, Diane F.; Domazlicky, Bruce

    2006-01-01

    The 2001 No Child Left Behind Act requires that schools make ''annual yearly progress'' in raising student achievement, or face possible sanctions. The No Child Left Behind Act places added emphasis on test scores, such as scores from the Missouri Assessment Program (MAP), to evaluate the performance of schools. In this paper, we investigate…

  3. A Thorough and Efficient Education: School Funding, Student Achievement and Productivity

    ERIC Educational Resources Information Center

    Ahlgrim, Richard W.

    2010-01-01

    Many school districts are facing stagnant or reduced funding (input) concurrent with demands for improved student achievement (output). In other words, there is pressure for all schools, even those schools with student populations of low socioeconomic status, to improve academic results (accountability for output) without a directly proportionate…

  4. A Strategy to Achieve High-Efficiency Organolead Trihalide Perovskite Solar Cells

    NASA Astrophysics Data System (ADS)

    Andalibi, Shabnam; Rostami, Ali; Darvish, Ghafar; Moravvej-Farshi, Mohammad Kazem

    2016-11-01

    Recent theoretical and experimental reports have shown that organometal lead halide perovskite solar cells have attracted attention as a low-cost photovoltaic technology offering high power conversion efficiency. However, the photovoltaic efficiency of these materials is still limited by poor chemical and structural stability in the case of methylammonium lead triiodide and by large bandgap in the case of methylammonium lead tribromide or trichloride. To obtain high-performance devices, we have investigated the computationally optimal efficiency for these materials using the detailed-balance method and present optimal intermediate-band perovskite solar cells with high open-circuit voltage. We model different halide perovskites using density function theory calculations and study their bandgap and absorption coefficient. Based on calculation results, surprisingly Hg doping in different halide perovskites introduces a narrow partially filled intermediate band in the forbidden bandgap. We investigate electrical and optical properties of MAPb0.97Hg0.03I3, MAPb0.96Hg0.04Br3, and MAPb0.96Hg0.04Cl3 and calculate the high absorption efficiency of the different perovskite structures to create thin films suitable for photovoltaic devices.

  5. A Strategy to Achieve High-Efficiency Organolead Trihalide Perovskite Solar Cells

    NASA Astrophysics Data System (ADS)

    Andalibi, Shabnam; Rostami, Ali; Darvish, Gafar; Moravvej-Farshi, Mohammad Kazem

    2016-07-01

    Recent theoretical and experimental reports have shown that organometal lead halide perovskite solar cells have attracted attention as a low-cost photovoltaic technology offering high power conversion efficiency. However, the photovoltaic efficiency of these materials is still limited by poor chemical and structural stability in the case of methylammonium lead triiodide and by large bandgap in the case of methylammonium lead tribromide or trichloride. To obtain high-performance devices, we have investigated the computationally optimal efficiency for these materials using the detailed-balance method and present optimal intermediate-band perovskite solar cells with high open-circuit voltage. We model different halide perovskites using density function theory calculations and study their bandgap and absorption coefficient. Based on calculation results, surprisingly Hg doping in different halide perovskites introduces a narrow partially filled intermediate band in the forbidden bandgap. We investigate electrical and optical properties of MAPb0.97Hg0.03I3, MAPb0.96Hg0.04Br3, and MAPb0.96Hg0.04Cl3 and calculate the high absorption efficiency of the different perovskite structures to create thin films suitable for photovoltaic devices.

  6. Achieving strategic cost advantages by focusing on back-office efficiency.

    PubMed

    McDowell, Jim

    2010-06-01

    A study of more than 270 hospitals over a four-year period highlighted a number of investments that can reduce hospitals' costs and improve efficiency, including the following: E-procurement systems. Electronic exchange of invoices and payments (and electronic receipt of payments). Human resources IT systems that reduce the need for manual entry of data. Shared services deployment.

  7. Combination of molecular, morphological, and interfacial engineering to achieve highly efficient and stable plastic solar cells.

    PubMed

    Chang, Chih-Yu; Cheng, Yen-Ju; Hung, Shih-Hsiu; Wu, Jhong-Sian; Kao, Wei-Shun; Lee, Chia-Hao; Hsu, Chain-Shu

    2012-01-24

    A flexible solar device showing exceptional air and mechanical stability is produced by simultaneously optimizing molecular structure, active layer morphology, and interface characteristics. The PFDCTBT-C8-based devices with inverted architecture exhibited excellent power conversion efficiencies of 7.0% and 6.0% on glass and flexible substrates, respectively.

  8. Achieving high performance polymer optoelectronic devices for high efficiency, long lifetime and low fabrication cost

    NASA Astrophysics Data System (ADS)

    Huang, Jinsong

    This thesis described three types of organic optoelectronic devices: polymer light emitting diodes (PLED), polymer photovoltaic solar cell, and organic photo detector. The research in this work focuses improving their performance including device efficiency, operation lifetime simplifying fabrication process. With further understanding in PLED device physics, we come up new device operation model and improved device architecture design. This new method is closely related to understanding of the science and physics at organic/metal oxide and metal oxide/metal interface. In our new device design, both material and interface are considered in order to confine and balance all injected carriers, which has been demonstrated very be successful in increasing device efficiency. We created two world records in device efficiency: 18 lm/W for white emission fluorescence PLED, 22 lm/W for red emission phosphorescence PLED. Slow solvent drying process has been demonstrated to significantly increase device efficiency in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C 61-butyric acid methyl ester (PCBM) mixture polymer solar cell. From the mobility study by time of flight, the increase of efficiency can be well correlated to the improved carrier transport property due to P3HT crystallization during slow solvent drying. And it is found that, similar to PLED, balanced carrier mobility is essential in high efficient polymer solar cell. There is also a revolution in our device fabrication method. A unique device fabrication method is presented by an electronic glue based lamination process combined with interface modification as a one-step polymer solar cell fabrication process. It can completely skip the thermal evaporation process, and benefit device lifetime by several merits: no air reactive. The device obtained is metal free, semi-transparent, flexible, self-encapsulated, and comparable efficiency with that by regular method. We found the photomultiplication (PM) phenomenon in C

  9. Experimental Determination of Operating and Maximum Power Transfer Efficiencies at Resonant Frequency in a Wireless Power Transfer System using PP Network Topology with Top Coupling

    NASA Astrophysics Data System (ADS)

    Ramachandran, Hema; Pillai, K. P. P.; Bindu, G. R.

    2016-08-01

    A two-port network model for a wireless power transfer system taking into account the distributed capacitances using PP network topology with top coupling is developed in this work. The operating and maximum power transfer efficiencies are determined analytically in terms of S-parameters. The system performance predicted by the model is verified with an experiment consisting of a high power home light load of 230 V, 100 W and is tested for two forced resonant frequencies namely, 600 kHz and 1.2 MHz. The experimental results are in close agreement with the proposed model.

  10. Experimental study of the maximum resolution and packing density achievable in sintered and non-sintered binder-jet 3D printed steel microchannels

    SciTech Connect

    Elliott, Amy M; Mehdizadeh Momen, Ayyoub; Benedict, Michael; Kiggans Jr, James O

    2015-01-01

    Developing high resolution 3D printed metallic microchannels is a challenge especially when there is an essential need for high packing density of the primary material. While high packing density could be achieved by heating the structure to the sintering temperature, some heat sensitive applications require other strategies to improve the packing density of primary materials. In this study the goal is to develop high green or pack densities microchannels on the scale of 2-300 microns which have a robust mechanical structure. Binder-jet 3D printing is an additive manufacturing process in which droplets of binder are deposited via inkjet into a bed of powder. By repeatedly spreading thin layers of powder and depositing binder into the appropriate 2D profiles, complex 3D objects can be created one layer at time. Microchannels with features on the order of 500 microns were fabricated via binder jetting of steel powder and then sintered and/or infiltrated with a secondary material. The average particle size of the steel powder was varied along with the droplet volume of the inkjet-deposited binder. The resolution of the process, packing density of the primary material, the subsequent features sizes of the microchannels, and the overall microchannel quality were characterized as a function of particle size distribution, droplet sizes and heat treatment temperatures.

  11. Maximum likelihood.

    PubMed

    Yang, Shuying; De Angelis, Daniela

    2013-01-01

    The maximum likelihood method is a popular statistical inferential procedure widely used in many areas to obtain the estimates of the unknown parameters of a population of interest. This chapter gives a brief description of the important concepts underlying the maximum likelihood method, the definition of the key components, the basic theory of the method, and the properties of the resulting estimates. Confidence interval and likelihood ratio test are also introduced. Finally, a few examples of applications are given to illustrate how to derive maximum likelihood estimates in practice. A list of references to relevant papers and software for a further understanding of the method and its implementation is provided.

  12. Identification of Energy Efficiency Opportunities through Building Data Analysis and Achieving Energy Savings through Improved Controls

    SciTech Connect

    Katipamula, Srinivas; Taasevigen, Danny J.; Koran, Bill

    2014-09-04

    This chapter will highlight analysis techniques to identify energy efficiency opportunities to improve operations and controls. A free tool, Energy Charting and Metrics (ECAM), will be used to assist in the analysis of whole-building, sub-metered, and/or data from the building automation system (BAS). Appendix A describes the features of ECAM in more depth, and also provide instructions for downloading ECAM and all resources pertaining to using ECAM.

  13. Propeller charts for the determination of the rotational speed for the maximum ratio of the propulsive efficiency to the specific fuel consumption

    NASA Technical Reports Server (NTRS)

    Biermann, David; Conway, Robert N

    1942-01-01

    A set of propeller operating efficiency charts, based on a coefficient from which the propeller rotational speed has been eliminated, is presented. These charts were prepared with data obtained from tests of full-size metal propellers in the NACA propeller-research tunnel. Working charts for nine propeller-body combinations are presented, including results from tests of dual-rotating propellers. These charts are to be used in the calculation of the range and the endurance of airplanes equipped with constant-speed propellers in which, for given flight conditions, it is desired to determine the propeller revolution speed that gives the maximum ratio of the propulsive efficiency to the specific fuel consumption. The coefficient on which the charts are based may be written in the form of a thrust coefficient or a thrust-power coefficient. A method of using the charts is outlined and sample computations for a typical airplane are included.

  14. [Bariatric surgery is more efficient than medical treatment in achieving remission in diabetes mellitus type 2].

    PubMed

    Klein, Mads; Rosenberg, Jacob; Gögenur, Ismail

    2013-04-01

    Observational studies have shown that bariatric surgery can lead to remission of diabetes mellitus type 2 (DMII), but randomized controlled trials have been lacking. Recently, randomized controlled trials comparing bariatric surgery with optimal medical treatment in patients suffering from poorly controlled DMII, have been performed. These trials show that bariatric surgery in general, and the malabsorptive procedures in particular, are more effective than medical treatment in achieving remission of DMII. These procedures should therefore be considered in the treatment of patients with DMII and obesity.

  15. Advanced liquid cooling in HCPVT systems to achieve higher energy efficiencies

    NASA Astrophysics Data System (ADS)

    Zimmermann, S.; Helmers, H.; Tiwari, M. K.; Escher, W.; Paredes, S.; Neves, P.; Poulikakos, D.; Wiesenfarth, M.; Bett, A. W.; Michel, B.

    2013-09-01

    The benefits of advanced thermal packaging are demonstrated through a receiver package consisting of a monolithic interconnected module (MIM) which is directly attached to a high performance microchannel heat sink. Those packages can be applied in high-concentration photovoltaic systems and the generated heat can be used in addition to the electrical power output (CPVT systems). Thus, the total energy efficiency of the system increases significantly. A detailed exergy analysis of the receiver power output underscores the advantages of the new cooling approach.

  16. On the maximum conversion efficiency into the 13.5-nm extreme ultraviolet emission under a steady-state laser ablation of tin microspheres

    NASA Astrophysics Data System (ADS)

    Basko, M. M.

    2016-08-01

    Theoretical investigation has been performed on the conversion efficiency (CE) into the 13.5-nm extreme ultraviolet (EUV) radiation in a scheme where spherical microspheres of tin (Sn) are simultaneously irradiated by two laser pulses with substantially different wavelengths. The low-intensity short-wavelength pulse is used to control the rate of mass ablation and the size of the EUV source, while the high-intensity long-wavelength pulse provides efficient generation of the EUV light at λ=13.5 nm. The problem of full optimization for maximizing the CE is formulated and solved numerically by performing two-dimensional radiation-hydrodynamics simulations with the RALEF-2D code under the conditions of steady-state laser illumination. It is shown that, within the implemented theoretical model, steady-state CE values approaching 9% are feasible; in a transient peak, the maximum instantaneous CE of 11.5% was calculated for the optimized laser-target configuration. The physical factors, bringing down the fully optimized steady-state CE to about one half of the absolute theoretical maximum of CE≈20 % for the uniform static Sn plasma, are analyzed in detail.

  17. Efficient Method of Achieving Agreements between Individuals and Organizations about RFID Privacy

    NASA Astrophysics Data System (ADS)

    Cha, Shi-Cho

    This work presents novel technical and legal approaches that address privacy concerns for personal data in RFID systems. In recent years, to minimize the conflict between convenience and the privacy risk of RFID systems, organizations have been requested to disclose their policies regarding RFID activities, obtain customer consent, and adopt appropriate mechanisms to enforce these policies. However, current research on RFID typically focuses on enforcement mechanisms to protect personal data stored in RFID tags and prevent organizations from tracking user activity through information emitted by specific RFID tags. A missing piece is how organizations can obtain customers' consent efficiently and flexibly. This study recommends that organizations obtain licenses automatically or semi-automatically before collecting personal data via RFID technologies rather than deal with written consents. Such digitalized and standard licenses can be checked automatically to ensure that collection and use of personal data is based on user consent. While individuals can easily control who has licenses and license content, the proposed framework provides an efficient and flexible way to overcome the deficiencies in current privacy protection technologies for RFID systems.

  18. Achieving Selective and Efficient Electrocatalytic Activity for CO2 Reduction Using Immobilized Silver Nanoparticles.

    PubMed

    Kim, Cheonghee; Jeon, Hyo Sang; Eom, Taedaehyeong; Jee, Michael Shincheon; Kim, Hyungjun; Friend, Cynthia M; Min, Byoung Koun; Hwang, Yun Jeong

    2015-11-01

    Selective electrochemical reduction of CO2 is one of the most sought-after processes because of the potential to convert a harmful greenhouse gas to a useful chemical. We have discovered that immobilized Ag nanoparticles supported on carbon exhibit enhanced Faradaic efficiency and a lower overpotential for selective reduction of CO2 to CO. These electrocatalysts were synthesized directly on the carbon support by a facile one-pot method using a cysteamine anchoring agent resulting in controlled monodispersed particle sizes. These synthesized Ag/C electrodes showed improved activities, specifically decrease of the overpotential by 300 mV at 1 mA/cm(2), and 4-fold enhanced CO Faradaic efficiency at -0.75 V vs RHE with the optimal particle size of 5 nm compared to polycrystalline Ag foil. DFT calculations enlightened that the specific interaction between Ag nanoparticle and the anchoring agents modified the catalyst surface to have a selectively higher affinity to the intermediate COOH over CO, which effectively lowers the overpotential. PMID:26447349

  19. Achieving Internet-based efficiencies in a rural IDS: a case study.

    PubMed

    Bacus, R; Zunke, R

    2001-09-01

    After suffering payment cuts resulting from the Balanced Budget Act of 1997, Colorado-Fayette Medical Center (CFMC), a not-for-profit, rural integrated delivery system in Texas, wanted to reduce costs by gaining systemwide Internet access for its internal information system at a reasonable price. An application service provider affiliated with the Texas Hospital Association, helped CFMC achieve its goals for the project by performing a needs assessment, installing a wide-area network (WAN) with Internet access, and training staff. The new WAN enabled CFMC to improve its Web presence, allow radiologic image viewing at all sites, negotiate more favorable prices from vendors, implement electronic communication for staff members, and take advantage of on-line education opportunities. CFMC has found that the monthly fee paid to THN is offset by savings on long-distance calls, Internet service provider fees, and marketing and advertising costs. PMID:11552587

  20. Metering Best Practices, A Guide to Achieving Utility Resource Efficiency, Release 2.0

    SciTech Connect

    Sullivan, Greg; Hunt, W. D.; Pugh, Ray; Sandusky, William F.; Koehler, Theresa M.; Boyd, Brian K.

    2011-08-31

    This release is an update and expansion of the information provided in Release 1.0 of the Metering Best Practice Guide that was issued in October 2007. This release, as was the previous release, was developed under the direction of the U.S. Department of Energy's Federal Energy Management Program (FEMP). The mission of FEMP is to facilitate the Federal Government's implementation of sound cost-effective energy management and investment practices to enhance the nation's energy security and environmental stewardship. Each of these activities is directly related to achieving requirements set forth in the Energy Policy Acts of 1992 and 2005, the Energy Independence and Security Act (EISA) of 2007, and the goals that have been established in Executive Orders 13423 and 13514 - and also those practices that are inherent in sound management of Federal financial and personnel resources.

  1. Progress toward achieving high power and high efficiency semipolar LEDs and their characterization

    NASA Astrophysics Data System (ADS)

    Zhong, Hong

    Performance of current commercially available wurtzite nitride based light-emitting diodes (LEDs), grown along the polar (0001) c-plane orientation, is limited by the presence of polarization-related electric fields inside multi-quantum wells (MQWs). The discontinuities in both spontaneous and piezoelectric polarization at the heterointerfaces result in internal electric fields in the quantum wells. These electric fields cause carrier separation [quantum confined Stark effect (QCSE)] and reduce the radiative recombination rate within the quantum wells. One approach to reduce and possibly eliminate the polarization-related effects is to grow III-nitride devices on crystal planes that are inclined with respect to the c-axis, i.e., on semipolar planes. In this dissertation, metalorganic chemical vapor deposition (MOCVD) has been employed for the homoepitaxial growth of GaN based LEDs on semipolar orientations. As a consequence of growing on high-quality bulk GaN substrates, the LEDs have significantly reduced threading dislocation and stacking fault densities, resulting in remarkable improvements in EQE and output power. High efficiency semipolar (1011) violet-blue and blue LEDs have been demonstrated without any intentional effort to enhance the light extraction from those devices. Optimizations of epitaxial structures have led to increased output power and external quantum efficiency. A silicone encapsulated single quantum well blue LED with peak wavelength of 444 nm with output power of 24.3 mW, external quantum efficiency of 43% and luminous efficacy of 75 lm/W (with phosphorescent coating) at 20 mA has been demonstrated. Polarization fields in strained (1011) and (112¯2) InGaN quantum wells have been experimentally determined through bias-dependent optical studies. Our results show that the polarization field flips its direction in semipolar InGaN quantum wells with large inclination angles (i.e. around 60°). This suggests that there exists a polarization

  2. Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers.

    PubMed

    Mathew, Simon; Yella, Aswani; Gao, Peng; Humphry-Baker, Robin; Curchod, Basile F E; Ashari-Astani, Negar; Tavernelli, Ivano; Rothlisberger, Ursula; Nazeeruddin, Md Khaja; Grätzel, Michael

    2014-03-01

    Dye-sensitized solar cells have gained widespread attention in recent years because of their low production costs, ease of fabrication and tunable optical properties, such as colour and transparency. Here, we report a molecularly engineered porphyrin dye, coded SM315, which features the prototypical structure of a donor-π-bridge-acceptor and both maximizes electrolyte compatibility and improves light-harvesting properties. Linear-response, time-dependent density functional theory was used to investigate the perturbations in the electronic structure that lead to improved light harvesting. Using SM315 with the cobalt(II/III) redox shuttle resulted in dye-sensitized solar cells that exhibit a high open-circuit voltage VOC of 0.91 V, short-circuit current density JSC of 18.1 mA cm(-2), fill factor of 0.78 and a power conversion efficiency of 13%.

  3. Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers

    NASA Astrophysics Data System (ADS)

    Mathew, Simon; Yella, Aswani; Gao, Peng; Humphry-Baker, Robin; Curchod, Basile F. E.; Ashari-Astani, Negar; Tavernelli, Ivano; Rothlisberger, Ursula; Nazeeruddin, Md. Khaja; Grätzel, Michael

    2014-03-01

    Dye-sensitized solar cells have gained widespread attention in recent years because of their low production costs, ease of fabrication and tunable optical properties, such as colour and transparency. Here, we report a molecularly engineered porphyrin dye, coded SM315, which features the prototypical structure of a donor-π-bridge-acceptor and both maximizes electrolyte compatibility and improves light-harvesting properties. Linear-response, time-dependent density functional theory was used to investigate the perturbations in the electronic structure that lead to improved light harvesting. Using SM315 with the cobalt(II/III) redox shuttle resulted in dye-sensitized solar cells that exhibit a high open-circuit voltage VOC of 0.91 V, short-circuit current density JSC of 18.1 mA cm-2, fill factor of 0.78 and a power conversion efficiency of 13%.

  4. Operations & Maintenance Best Practices - A Guide to Achieving Operational Efficiency (Release 3)

    SciTech Connect

    Sullivan, Greg; Pugh, Ray; Melendez, Aldo P.; Hunt, W. D.

    2010-08-04

    This guide highlights operations and maintenance programs targeting energy and water efficiency that are estimated to save 5% to 20% on energy bills without a significant capital investment. The purpose of this guide is to provide you, the Operations and Maintenance (O&M)/Energy manager and practitioner, with useful information about O&M management, technologies, energy and water efficiency, and cost-reduction approaches. To make this guide useful and to reflect your needs and concerns, the authors met with O&M and Energy managers via Federal Energy Management Program (FEMP) workshops. In addition, the authors conducted extensive literature searches and contacted numerous vendors and industry experts. The information and case studies that appear in this guide resulted from these activities. It needs to be stated at the outset that this guide is designed to provide information on effective O&M as it applies to systems and equipment typically found at Federal facilities. This guide is not designed to provide the reader with step-by-step procedures for performing O&M on any specific piece of equipment. Rather, this guide first directs the user to the manufacturer's specifications and recommendations. In no way should the recommendations in this guide be used in place of manufacturer's recommendations. The recommendations in this guide are designed to supplement those of the manufacturer, or, as is all too often the case, provide guidance for systems and equipment for which all technical documentation has been lost. As a rule, this guide will first defer to the manufacturer's recommendations on equipment operation and maintenance.

  5. The use of ECDIS equipment to achieve an optimum value for energy efficiency operation index

    NASA Astrophysics Data System (ADS)

    Acomi, N.; Acomi, O. C.; Stanca, C.

    2015-11-01

    To reduce air pollution produced by ships, the International Maritime Organization has developed a set of technical, operational and management measures. The subject of our research addresses the operational measures for minimizing CO2 air emissions and the way how the emission value could be influenced by external factors regardless of ship-owners’ will. This study aims to analyse the air emissions for a loaded voyage leg performed by an oil tanker. The formula that allows us to calculate the predicted Energy Efficiency Operational Index involves the estimation of distance and fuel consumption, while the quantity of cargo is known. The electronic chart display and information system, ECDIS Simulation Software, will be used for adjusting the passage plan in real time, given the predicted severe environmental conditions. The distance will be determined using ECDIS, while the prediction of the fuel consumption will consider the sea trial and the vessel experience records. That way it will be possible to compare the estimated EEOI value in the case of great circle navigation in adverse weather condition with the estimated EEOI value for weather navigation.

  6. Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers

    PubMed Central

    Buyel, Johannes F.; Gruchow, Hannah M.; Fischer, Rainer

    2015-01-01

    The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m−2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre–coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m−2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins. PMID:26734037

  7. Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers.

    PubMed

    Buyel, Johannes F; Gruchow, Hannah M; Fischer, Rainer

    2015-01-01

    The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m(-2) when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre-coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m(-2) with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

  8. Efficient and anonymous two-factor user authentication in wireless sensor networks: achieving user anonymity with lightweight sensor computation.

    PubMed

    Nam, Junghyun; Choo, Kim-Kwang Raymond; Han, Sangchul; Kim, Moonseong; Paik, Juryon; Won, Dongho

    2015-01-01

    A smart-card-based user authentication scheme for wireless sensor networks (hereafter referred to as a SCA-WSN scheme) is designed to ensure that only users who possess both a smart card and the corresponding password are allowed to gain access to sensor data and their transmissions. Despite many research efforts in recent years, it remains a challenging task to design an efficient SCA-WSN scheme that achieves user anonymity. The majority of published SCA-WSN schemes use only lightweight cryptographic techniques (rather than public-key cryptographic techniques) for the sake of efficiency, and have been demonstrated to suffer from the inability to provide user anonymity. Some schemes employ elliptic curve cryptography for better security but require sensors with strict resource constraints to perform computationally expensive scalar-point multiplications; despite the increased computational requirements, these schemes do not provide user anonymity. In this paper, we present a new SCA-WSN scheme that not only achieves user anonymity but also is efficient in terms of the computation loads for sensors. Our scheme employs elliptic curve cryptography but restricts its use only to anonymous user-to-gateway authentication, thereby allowing sensors to perform only lightweight cryptographic operations. Our scheme also enjoys provable security in a formal model extended from the widely accepted Bellare-Pointcheval-Rogaway (2000) model to capture the user anonymity property and various SCA-WSN specific attacks (e.g., stolen smart card attacks, node capture attacks, privileged insider attacks, and stolen verifier attacks).

  9. Efficient and anonymous two-factor user authentication in wireless sensor networks: achieving user anonymity with lightweight sensor computation.

    PubMed

    Nam, Junghyun; Choo, Kim-Kwang Raymond; Han, Sangchul; Kim, Moonseong; Paik, Juryon; Won, Dongho

    2015-01-01

    A smart-card-based user authentication scheme for wireless sensor networks (hereafter referred to as a SCA-WSN scheme) is designed to ensure that only users who possess both a smart card and the corresponding password are allowed to gain access to sensor data and their transmissions. Despite many research efforts in recent years, it remains a challenging task to design an efficient SCA-WSN scheme that achieves user anonymity. The majority of published SCA-WSN schemes use only lightweight cryptographic techniques (rather than public-key cryptographic techniques) for the sake of efficiency, and have been demonstrated to suffer from the inability to provide user anonymity. Some schemes employ elliptic curve cryptography for better security but require sensors with strict resource constraints to perform computationally expensive scalar-point multiplications; despite the increased computational requirements, these schemes do not provide user anonymity. In this paper, we present a new SCA-WSN scheme that not only achieves user anonymity but also is efficient in terms of the computation loads for sensors. Our scheme employs elliptic curve cryptography but restricts its use only to anonymous user-to-gateway authentication, thereby allowing sensors to perform only lightweight cryptographic operations. Our scheme also enjoys provable security in a formal model extended from the widely accepted Bellare-Pointcheval-Rogaway (2000) model to capture the user anonymity property and various SCA-WSN specific attacks (e.g., stolen smart card attacks, node capture attacks, privileged insider attacks, and stolen verifier attacks). PMID:25849359

  10. Efficient and Anonymous Two-Factor User Authentication in Wireless Sensor Networks: Achieving User Anonymity with Lightweight Sensor Computation

    PubMed Central

    Nam, Junghyun; Choo, Kim-Kwang Raymond; Han, Sangchul; Kim, Moonseong; Paik, Juryon; Won, Dongho

    2015-01-01

    A smart-card-based user authentication scheme for wireless sensor networks (hereafter referred to as a SCA-WSN scheme) is designed to ensure that only users who possess both a smart card and the corresponding password are allowed to gain access to sensor data and their transmissions. Despite many research efforts in recent years, it remains a challenging task to design an efficient SCA-WSN scheme that achieves user anonymity. The majority of published SCA-WSN schemes use only lightweight cryptographic techniques (rather than public-key cryptographic techniques) for the sake of efficiency, and have been demonstrated to suffer from the inability to provide user anonymity. Some schemes employ elliptic curve cryptography for better security but require sensors with strict resource constraints to perform computationally expensive scalar-point multiplications; despite the increased computational requirements, these schemes do not provide user anonymity. In this paper, we present a new SCA-WSN scheme that not only achieves user anonymity but also is efficient in terms of the computation loads for sensors. Our scheme employs elliptic curve cryptography but restricts its use only to anonymous user-to-gateway authentication, thereby allowing sensors to perform only lightweight cryptographic operations. Our scheme also enjoys provable security in a formal model extended from the widely accepted Bellare-Pointcheval-Rogaway (2000) model to capture the user anonymity property and various SCA-WSN specific attacks (e.g., stolen smart card attacks, node capture attacks, privileged insider attacks, and stolen verifier attacks). PMID:25849359

  11. Achieving Maximum Integration Utilizing Requirements Flow Down

    NASA Technical Reports Server (NTRS)

    Archiable, Wes; Askins, Bruce

    2011-01-01

    A robust and experienced systems engineering team is essential for a successful program. It is often a challenge to build a core systems engineering team early enough in a program to maximize integration and assure a common path for all supporting teams in a project. Ares I was no exception. During the planning of IVGVT, the team had many challenges including lack of: early identification of stakeholders, team training in NASA s system engineering practices, solid requirements flow down and a top down documentation strategy. The IVGVT team started test planning early in the program before the systems engineering framework had been matured due to an aggressive schedule. Therefore the IVGVT team increased their involvement in the Constellation systems engineering effort. Program level requirements were established that flowed down to IVGVT aligning all stakeholders to a common set of goals. The IVGVT team utilized the APPEL REQ Development Management course providing the team a NASA focused model to follow. The IVGVT team engaged directly with the model verification and validation process to assure that a solid set of requirements drove the need for the test event. The IVGVT team looked at the initial planning state, analyzed the current state and then produced recommendations for the ideal future state of a wide range of systems engineering functions and processes. Based on this analysis, the IVGVT team was able to produce a set of lessons learned and to provide suggestions for future programs or tests to use in their initial planning phase.

  12. Titanate cathodes with enhanced electrical properties achieved via growing surface Ni particles toward efficient carbon dioxide electrolysis.

    PubMed

    Gan, Lizhen; Ye, Lingting; Tao, Shanwen; Xie, Kui

    2016-01-28

    Ionic conduction in perovskite oxide is commonly tailored by element doping in lattices to create charge carriers, while few studies have been focused on ionic conduction enhancement through tailoring microstructures. In this work, remarkable enhancement of ionic conduction in titanate has been achieved via in situ growing active nickel nanoparticles on an oxide surface by controlling the oxide material nonstoichiometry. The combined use of XRD, SEM, XPS and EDS indicates that the exsolution/dissolution of the nickel nanoparticles is completely reversible in redox cycles. With the synergetic effect of enhanced ionic conduction of titanate and the presence of catalytic active Ni nanocatalysts, significant improvement of electrocatalytic performances of the titanate cathode is demonstrated. A current density of 0.3 A cm(-2) with a Faradic efficiency of 90% has been achieved for direct carbon dioxide electrolysis in a 2 mm-thick YSZ-supported solid oxide electrolyzer with the modified titanate cathode at 2 V and 1073 K. PMID:26743799

  13. First-principles analysis of the spectroscopic limited maximum efficiency of photovoltaic absorber layers for CuAu-like chalcogenides and silicon.

    PubMed

    Bercx, Marnik; Sarmadian, Nasrin; Saniz, Rolando; Partoens, Bart; Lamoen, Dirk

    2016-07-27

    Chalcopyrite semiconductors are of considerable interest for application as absorber layers in thin-film photovoltaic cells. When growing films of these compounds, however, they are often found to contain CuAu-like domains, a metastable phase of chalcopyrite. It has been reported that for CuInS2, the presence of the CuAu-like phase improves the short circuit current of the chalcopyrite-based photovoltaic cell. We investigate the thermodynamic stability of both phases for a selected list of I-III-VI2 materials using a first-principles density functional theory approach. For the CuIn-VI2 compounds, the difference in formation energy between the chalcopyrite and CuAu-like phase is found to be close to 2 meV per atom, indicating a high likelihood of the presence of CuAu-like domains. Next, we calculate the spectroscopic limited maximum efficiency (SLME) of the CuAu-like phase and compare the results with those of the corresponding chalcopyrite phase. We identify several candidates with a high efficiency, such as CuAu-like CuInS2, for which we obtain an SLME of 29% at a thickness of 500 nm. We observe that the SLME can have values above the Shockley-Queisser (SQ) limit, and show that this can occur because the SQ limit assumes the absorptivity to be a step function, thus overestimating the radiative recombination in the detailed balance approach. This means that it is possible to find higher theoretical efficiencies within this framework simply by calculating the J-V characteristic with an absorption spectrum. Finally, we expand our SLME analysis to indirect band gap absorbers by studying silicon, and find that the SLME quickly overestimates the reverse saturation current of indirect band gap materials, drastically lowering their calculated efficiency.

  14. Benefits of Hybrid-Electric Propulsion to Achieve 4x Increase in Cruise Efficiency for a VTOL Aircraft

    NASA Technical Reports Server (NTRS)

    Fredericks, William J.; Moore, Mark D.; Busan, Ronald C.

    2013-01-01

    Electric propulsion enables radical new vehicle concepts, particularly for Vertical Takeoff and Landing (VTOL) aircraft because of their significant mismatch between takeoff and cruise power conditions. However, electric propulsion does not merely provide the ability to normalize the power required across the phases of flight, in the way that automobiles also use hybrid electric technologies. The ability to distribute the thrust across the airframe, without mechanical complexity and with a scale-free propulsion system, is a new degree of freedom for aircraft designers. Electric propulsion is scale-free in terms of being able to achieve highly similar levels of motor power to weight and efficiency across a dramatic scaling range. Applying these combined principles of electric propulsion across a VTOL aircraft permits an improvement in aerodynamic efficiency that is approximately four times the state of the art of conventional helicopter configurations. Helicopters typically achieve a lift to drag ratio (L/D) of between 4 and 5, while the VTOL aircraft designed and developed in this research were designed to achieve an L/D of approximately 20. Fundamentally, the ability to eliminate the problem of advancing and retreating rotor blades is shown, without resorting to unacceptable prior solutions such as tail-sitters. This combination of concept and technology also enables a four times increase in range and endurance while maintaining the full VTOL and hover capability provided by a helicopter. Also important is the ability to achieve low disc-loading for low ground impingement velocities, low noise and hover power minimization (thus reducing energy consumption in VTOL phases). This combination of low noise and electric propulsion (i.e. zero emissions) will produce a much more community-friendly class of vehicles. This research provides a review of the concept brainstorming, configuration aerodynamic and mission analysis, as well as subscale prototype construction and

  15. Contributions of the secondary jet to the maximum tangential velocity and to the collection efficiency of the fixed guide vane type axial flow cyclone dust collector

    NASA Astrophysics Data System (ADS)

    Ogawa, Akira; Anzou, Hideki; Yamamoto, So; Shimagaki, Mituru

    2015-11-01

    In order to control the maximum tangential velocity Vθm(m/s) of the turbulent rotational air flow and the collection efficiency ηc (%) using the fly ash of the mean diameter XR50=5.57 µm, two secondary jet nozzles were installed to the body of the axial flow cyclone dust collector with the body diameter D1=99mm. Then in order to estimate Vθm (m/s), the conservation theory of the angular momentum flux with Ogawa combined vortex model was applied. The comparisons of the estimated results of Vθm(m/s) with the measured results by the cylindrical Pitot-tube were shown in good agreement. And also the estimated collection efficiencies ηcth (%) basing upon the cut-size Xc (µm) which was calculated by using the estimated Vθ m(m/s) and also the particle size distribution R(Xp) were shown a little higher values than the experimental results due to the re-entrainment of the collected dust. The best method for adjustment of ηc (%) related to the contribution of the secondary jet flow is principally to apply the centrifugal effect Φc (1). Above stated results are described in detail.

  16. Minimum energy as the general form of critical flow and maximum flow efficiency and for explaining variations in river channel pattern

    NASA Astrophysics Data System (ADS)

    Huang, He Qing; Chang, Howard H.; Nanson, Gerald C.

    2004-04-01

    Although the Bélanger-Böss theorem of critical flow has been widely applied in open channel hydraulics, it was derived from the laws governing ideal frictionless flow. This study explores a more general expression of this theorem and examines its applicability to flow with friction and sediment transport. It demonstrates that the theorem can be more generally presented as the principle of minimum energy (PME), with maximum efficiency of energy use and minimum friction or minimum energy dissipation as its equivalents. Critical flow depth under frictionless conditions, the best hydraulic section where friction is introduced, and the most efficient alluvial channel geometry where both friction and sediment transport apply are all shown to be the products of PME. Because PME in liquids characterizes the stationary state of motion in solid materials, flow tends to rapidly expend excess energy when more than minimally demanded energy is available. This leads to the formation of relatively stable but dynamic energy-consuming meandering and braided channel planforms and explains the existence of various extremal hypotheses.

  17. Design and synthesis of dendritic molecular transporter that achieves efficient in vivo delivery of morpholino antisense oligo.

    PubMed

    Li, Yong-Fu; Morcos, Paul A

    2008-07-01

    Safe and efficient in vivo delivery of Morpholino antisense oligos was probably the last and most difficult challenge for the broad application of antisense in animal research and therapeutics. Several arginine-rich peptides effective for in vivo delivery of Morpholino antisense oligos require rather complex and expensive procedures for synthesis and conjugation. This work describes the design and synthesis of a dendritic transporter in a most concise manner where the selection of the core scaffold, functional group multiplication, orthogonal protecting group manipulation, solid phase conjugation, and off-resin perguanidinylation of the transporter structure are all orchestrated for efficient assembly. We utilized triazine as a core to provide a site for on-column conjugation to the Morpholino oligo and to anchor functional side arms which, after extension, multiplication, and deprotection, are subsequently converted from primary amines to the eight guanidinium headgroups that serve for transport across cell membranes. Intravenous administration of the delivery-enabled Morpholino into a splice-reporter strain of transgenic living mice results in de novo expression of splice-corrected green fluorescent protein in a broad range of tissues and organs in those treated mice. This rigorously demonstrates that this new dendritic transporter achieves effective delivery of a Morpholino oligo into the cytosol/nuclear compartment of cells systemically in vivo. The practical conjugation process may overcome any availability limitation for routine use by the scientific community, and the efficient delivery ability of this transporter may advance the application of Morpholino antisense technology in animals.

  18. Analyzing the possibility of achieving more efficient cooling of water in the evaporative cooling towers of the Armenian NPP

    NASA Astrophysics Data System (ADS)

    Petrosyan, V. G.; Yeghoyan, E. A.

    2015-10-01

    The specific features of the service cooling water system used at the Armenian NPP and modifications made in the arrangement for supplying water to the water coolers in order to achieve more efficient cooling are presented. The mathematical model applied in carrying out the analyses is described, the use of which makes it possible to investigate the operation of parallel-connected cooling towers having different hydraulic and thermal loads. When the third standby cooling tower is put into operation (with the same flow rate of water supplied to the water coolers), the cooled water temperature is decreased by around 2-3°C in the range of atmospheric air temperatures 0-35°C. However, the introduced water distribution arrangement with a decreased spraying density has limitation on its use at negative outdoor air temperatures due to the hazard intense freezing of the fill in the cooling tower peripheral zone. The availability of standby cooling towers in the shutdown Armenian NPP power unit along with the planned full replacement of the cooling tower process equipment create good possibilities for achieving a deeper water cooling extent and better efficiency of the NPP. The present work was carried out with the aim of achieving maximally efficient use of existing possibilities and for elaborating the optimal cooling tower modernization version. Individual specific heat-andmass transfer processes in the chimney-type evaporative cooling towers are analyzed. An improved arrangement for distributing cooled water over the cooling tower spraying area (during its operation with a decreased flow rate) is proposed with the aim of cooling water to a deeper extent and preserving the possibility of using the cooling towers in winter. The main idea behind improving the existing arrangement is to exclude certain zones of the cooling tower featuring inefficient cooling from operation. The effectiveness of introducing the proposed design is proven by calculations (taking as an

  19. Babesia and its hosts: adaptation to long-lasting interactions as a way to achieve efficient transmission

    PubMed Central

    Chauvin, Alain; Moreau, Emmanuelle; Bonnet, Sarah; Plantard, Olivier; Malandrin, Laurence

    2009-01-01

    Babesia, the causal agent of babesiosis, are tick-borne apicomplexan protozoa. True babesiae (Babesia genus sensu stricto) are biologically characterized by direct development in erythrocytes and by transovarial transmission in the tick. A large number of true Babesia species have been described in various vertebrate and tick hosts. This review presents the genus then discusses specific adaptations of Babesia spp. to their hosts to achieve efficient transmission. The main adaptations lead to long-lasting interactions which result in the induction of two reservoirs: in the vertebrate host during low long-term parasitemia and throughout the life cycle of the tick host as a result of transovarial and transstadial transmission. The molecular bases of these adaptations in vertebrate hosts are partially known but few of the tick-host interaction mechanisms have been elucidated. PMID:19379662

  20. From here to efficiency : time lags between the introduction of new technology and the achievement of fuel savings.

    SciTech Connect

    Mintz, M.; Vyas, A.; Wang, M.; Stodolsky, F.; Cuenca, R.; Gaines, L.

    1999-12-03

    In this paper, the energy savings of new technology offering significant improvements in fuel efficiency are tracked for over 20 years as vehicles incorporating that technology enter the fleet and replace conventional light-duty vehicles. Two separate analyses are discussed: a life-cycle analysis of aluminum-intensive vehicles and a fuel-cycle analysis of the energy and greenhouse gas emissions of double vs. triple fuel-economy vehicles. In both efforts, market-penetration modeling is used to simulate the rate at which new technology enters the new fleet, and stock-adjustment modeling is used to capture the inertia in turnover of new and existing current-technology vehicles. Together, these two effects--slowed market penetration and delayed vehicle replacement--increase the time lag between market introduction and the achievement of substantial energy savings. In both cases, 15-20 years elapse, before savings approach these levels.

  1. Petroleum production at Maximum Efficient Rate Naval Petroleum Reserve No. 1 (Elk Hills), Kern County, California. Final Supplemental Environmental Impact Statement

    SciTech Connect

    Not Available

    1993-07-01

    This document provides an analysis of the potential impacts associated with the proposed action, which is continued operation of Naval Petroleum Reserve No. I (NPR-1) at the Maximum Efficient Rate (MER) as authorized by Public law 94-258, the Naval Petroleum Reserves Production Act of 1976 (Act). The document also provides a similar analysis of alternatives to the proposed action, which also involve continued operations, but under lower development scenarios and lower rates of production. NPR-1 is a large oil and gas field jointly owned and operated by the federal government and Chevron U.SA Inc. (CUSA) pursuant to a Unit Plan Contract that became effective in 1944; the government`s interest is approximately 78% and CUSA`s interest is approximately 22%. The government`s interest is under the jurisdiction of the United States Department of Energy (DOE). The facility is approximately 17,409 acres (74 square miles), and it is located in Kern County, California, about 25 miles southwest of Bakersfield and 100 miles north of Los Angeles in the south central portion of the state. The environmental analysis presented herein is a supplement to the NPR-1 Final Environmental Impact Statement of that was issued by DOE in 1979 (1979 EIS). As such, this document is a Supplemental Environmental Impact Statement (SEIS).

  2. Lipid Encapsulation Provides Insufficient Total-Tract Digestibility to Achieve an Optimal Transfer Efficiency of Fatty Acids to Milk Fat

    PubMed Central

    Bainbridge, Melissa; Kraft, Jana

    2016-01-01

    Transfer efficiencies of rumen-protected n-3 fatty acids (FA) to milk are low, thus we hypothesized that rumen-protection technologies allow for biohydrogenation and excretion of n-3 FA. The objectives of this study were to i) investigate the ruminal protection and post-ruminal release of the FA derived from the lipid-encapsulated echium oil (EEO), and ii) assess the bioavailability and metabolism of the EEO-derived FA through measuring the FA content in plasma lipid fractions, feces, and milk. The EEO was tested for rumen stability using the in situ nylon bag technique, then the apparent total-tract digestibility was assessed in vivo using six Holstein dairy cattle. Diets consisted of a control (no EEO); 1.5% of dry matter (DM) as EEO and 1.5% DM as encapsulation matrix; and 3% DM as EEO. The EEO was rumen-stable and had no effect on animal production. EEO-derived FA were incorporated into all plasma lipid fractions, with the highest proportion of n-3 FA observed in cholesterol esters. Fecal excretion of EEO-derived FA ranged from 7–14%. Biohydrogenation products increased in milk, plasma, and feces with EEO supplementation. In conclusion, lipid-encapsulation provides inadequate digestibility to achieve an optimal transfer efficiency of n-3 FA to milk. PMID:27741299

  3. Hands-On, Demonstration, and Videotape Laboratories for Non-Science Majors in a Food Science Course: Achievement, Attitude, and Efficiency

    ERIC Educational Resources Information Center

    Johnson, H. L.; Trout, B. L.; Brekke, C. J.; Luedecke, L. O.

    2004-01-01

    Student achievement, attitude, and instructional efficiency were determined for hands-on and for live and videotape demonstration laboratories for nonscience majors. Each of 3 laboratory sections experienced 3 different teaching methods for one 4-wk unit. No significant difference in achievement was found among the laboratory methods. An attitude…

  4. A 12%-efficient upgraded metallurgical grade silicon-organic heterojunction solar cell achieved by a self-purifying process.

    PubMed

    Zhang, Jie; Song, Tao; Shen, Xinlei; Yu, Xuegong; Lee, Shuit-Tong; Sun, Baoquan

    2014-11-25

    Low-quality silicon such as upgraded metallurgical-grade (UMG) silicon promises to reduce the material requirements for high-performance cost-effective photovoltaics. So far, however, UMG silicon currently exhibits the short diffusion length and serious charge recombination associated with high impurity levels, which hinders the performance of solar cells. Here, we used a metal-assisted chemical etching (MACE) method to partially upgrade the UMG silicon surface. The silicon was etched into a nanostructured one by the MACE process, associated with removing impurities on the surface. Meanwhile, nanostructured forms of UMG silicon can benefit improved light harvesting with thin substrates, which can relax the requirement of material purity for high photovoltaic performance. In order to suppress the large surface recombination due to increased surface area of nanostructured UMG silicon, a post chemical treatment was used to decrease the surface area. A solution-processed conjugated polymer of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was deposited on UMG silicon at low temperature (<150 °C) to form a heterojunction to avoid any impurity diffusion in the silicon substrate. By optimizing the thickness of silicon and suppressing the charge recombination at the interface between thin UMG silicon/PEDOT:PSS, we are able to achieve 12.0%-efficient organic-inorganic hybrid solar cells, which are higher than analogous UMG silicon devices. We show that the modified UMG silicon surface can increase the minority carrier lifetime because of reduced impurity and surface area. Our results suggest a design rule for an efficient silicon solar cell with low-quality silicon absorbers.

  5. Efficient Consistency Achievement of Federated Identity and Access Management Based on a Novel Self-Adaptable Approach

    NASA Astrophysics Data System (ADS)

    Cha, Shi-Cho; Chang, Hsiang-Meng

    Federated identity and access management (FIAM) systems enable a user to access services provided by various organizations seamlessly. In FIAM systems, service providers normally stipulate that their users show assertions issued by allied parties to use their services as well as determine user privileges based on attributes in the assertions. However, the integrity of the attributes is important under certain circumstances. In such a circumstance, all released assertions should reflect modifications made to user attributes. Despite the ability to adopt conventional certification revocation technologies, including CRL or OCSP, to revoke an assertion and request the corresponding user to obtain a new assertion, re-issuing an entirely new assertion if only one attribute, such as user location or other environmental information, is changed would be inefficient. Therefore, this work presents a self-adaptive framework to achieve consistency in federated identity and access management systems (SAFIAM). In SAFIAM, an identity provider (IdP), which authenticates users and provides user attributes, should monitor access probabilities according to user attributes. The IdP can then adopt the most efficient means of ensuring data integrity of attributes based on related access probabilities. While Internet-based services emerge daily that have various access probabilities with respect to their user attributes, the proposed self-adaptive framework significantly contributes to efforts to streamline the use of FIAM systems.

  6. Using interlayer step-wise triplet transfer to achieve an efficient white organic light-emitting diode with high color-stability

    SciTech Connect

    Wang, Qi; Ma, Dongge Ding, Junqiao; Wang, Lixiang; Leo, Karl; Qiao, Qiquan; Jia, Huiping; Gnade, Bruce E.

    2014-05-12

    An efficient phosphorescent white organic light emitting-diode with a red-green-blue tri-emitting-layer structure is reported. The host of the red dopant possesses a lower triplet-energy than the green dye. An interlayer step-wise triplet transfer via blue dye → green dye → red host → red dye is achieved. This mechanism allows an efficient triplet harvesting by the three dopants, thus maintaining a balanced white light and reducing energy loss. Moreover, the color stability of the device is improved significantly. The white device not only achieves a peak external quantum efficiency of 21.1 ± 0.8% and power efficiency of 37.5 ± 1.4 lm/W but shows no color shift over a wide range of voltages.

  7. Achieving greenhouse gas emission reductions in developing countries through energy efficient lighting projects in the Clean Development Mechanism (CDM)

    SciTech Connect

    Figueres, C.; Bosi, M.

    2006-11-15

    Energy efficiency can help address the challenge of increasing access to modern energy services, reduce the need for capital-intensive supply investments as well as mitigating climate change. Efficient lighting is a promising sector for improving the adequacy and reliability of power systems and reducing emissions in developing countries. However, these measures are hardly represented in the CDM portfolio. The COP/MOP decision to include programs of activities in the CDM could open the door to the implementation of a large number of energy efficiency projects in developing countries. Since GHG reductions are essentially the emission equivalent of energy savings, the CDM can benefit from long established energy efficiency methodologies for quantifying energy savings and fulfilling CDM methodological requirements. The integration of the CDM into energy efficiency programs could help spur a necessary transformation in the lighting market.

  8. ACHIEVING PERCEPTUAL-MOTOR EFFICIENCY, A SPACE-ORIENTED APPROACH TO LEARNING. PERCEPTUAL MOTOR CURRICULUM, VOLUME I.

    ERIC Educational Resources Information Center

    BARSCH, RAY H.

    THE FIRST OF A 3-VOLUME PERCEPTUAL MOTOR CURRICULUM, THE BOOK DESCRIBES A PROGRAM BASED ON A THEORY OF MOVEMENT WHICH THE AUTHOR LABELS MOVIGENICS (THE STUDY OF THE ORIGIN AND DEVELOPMENT OF PATTERNS OF MOVEMENT IN MAN AND THE RELATIONSHIP OF THESE MOVEMENTS TO HIS LEARNING EFFICIENCY). TEN BASIC CONSTRUCTS OF MOVIGENICS ARE OUTLINED, AND THE…

  9. Solar-to-hydrogen efficiency exceeding 2.5% achieved for overall water splitting with an all earth-abundant dual-photoelectrode.

    PubMed

    Ding, Chunmei; Qin, Wei; Wang, Nan; Liu, Guiji; Wang, Zhiliang; Yan, Pengli; Shi, Jingying; Li, Can

    2014-08-01

    The solar-to-hydrogen (STH) efficiency of a traditional mono-photoelectrode photoelectrochemical water splitting system has long been limited as large external bias is required. Herein, overall water splitting with STH efficiency exceeding 2.5% was achieved using a self-biased photoelectrochemical-photovoltaic coupled system consisting of an all earth-abundant photoanode and a Si-solar-cell-based photocathode connected in series under parallel illumination. We found that parallel irradiation mode shows higher efficiency than tandem illumination especially for photoanodes with a wide light absorption range, probably as the driving force for water splitting reaction is larger and the photovoltage loss is smaller in the former. This work essentially takes advantage of a tandem solar cell which can enhance the solar-to-electricity efficiency from another point of view.

  10. Solar-to-hydrogen efficiency exceeding 2.5% achieved for overall water splitting with an all earth-abundant dual-photoelectrode.

    PubMed

    Ding, Chunmei; Qin, Wei; Wang, Nan; Liu, Guiji; Wang, Zhiliang; Yan, Pengli; Shi, Jingying; Li, Can

    2014-08-01

    The solar-to-hydrogen (STH) efficiency of a traditional mono-photoelectrode photoelectrochemical water splitting system has long been limited as large external bias is required. Herein, overall water splitting with STH efficiency exceeding 2.5% was achieved using a self-biased photoelectrochemical-photovoltaic coupled system consisting of an all earth-abundant photoanode and a Si-solar-cell-based photocathode connected in series under parallel illumination. We found that parallel irradiation mode shows higher efficiency than tandem illumination especially for photoanodes with a wide light absorption range, probably as the driving force for water splitting reaction is larger and the photovoltage loss is smaller in the former. This work essentially takes advantage of a tandem solar cell which can enhance the solar-to-electricity efficiency from another point of view. PMID:24956231

  11. Carrots and Sticks: A Comprehensive Business Model for the Successful Achievement of Energy Efficiency Resource Standards Environmental Energy Technologies DivisionMarch 2011

    SciTech Connect

    Satchwell, Andrew; Cappers, Peter; Goldman, Charles

    2011-03-22

    Energy efficiency resource standards (EERS) are a prominent strategy to potentially achieve rapid and aggressive energy savings goals in the U.S. As of December 2010, twenty-six U.S. states had some form of an EERS with savings goals applicable to energy efficiency (EE) programs paid for by utility customers. The European Union has initiated a similar type of savings goal, the Energy End-use Efficiency and Energy Services Directive, where it is being implemented in some countries through direct partnership with regulated electric utilities. U.S. utilities face significant financial disincentives under traditional regulation which affects the interest of shareholders and managers in aggressively pursuing cost-effective energy efficiency. Regulators are considering some combination of mandated goals ('sticks') and alternative utility business model components ('carrots' such as performance incentives) to align the utility's business and financial interests with state and federal energy efficiency public policy goals. European countries that have directed their utilities to administer EE programs have generally relied on non-binding mandates and targets; in the U.S., most state regulators have increasingly viewed 'carrots' as a necessary condition for successful achievement of energy efficiency goals and targets. In this paper, we analyze the financial impacts of an EERS on a large electric utility in the State of Arizona using a pro-forma utility financial model, including impacts on utility earnings, customer bills and rates. We demonstrate how a viable business model can be designed to improve the business case while retaining sizable ratepayer benefits. Quantifying these concerns and identifying ways they can be addressed are crucial steps in gaining the support of major stakeholder groups - lessons that can apply to other countries looking to significantly increase savings targets that can be achieved from their own utility-administered EE programs.

  12. Low-cost and no-cost practice to achieve energy efficiency of government office buildings: A case study in federal territory of Malaysia

    NASA Astrophysics Data System (ADS)

    Tahir, Mohamad Zamhari; Nawi, Mohd Nasrun Mohd; Ibrahim, Amlus

    2016-08-01

    This paper presents the findings of a case study to achieve energy-efficient performance of conventional office buildings in Malaysia. Two multi-storey office buildings in Federal Territory of Malaysia have been selected. The aim is to study building energy saving potential then to highlight the appropriate measures that can be implemented. Data was collected using benchmarking method by comparing the measured consumption to other similar office buildings and a series of preliminary audit which involves interviews, a brief review of utility and operating data as well as a walkthrough in the buildings. Additionally, in order to get a better understanding of major energy consumption in the selected buildings, general audit have been conducted to collect more detailed information about building operation. In the end, this study emphasized low-cost and no-cost practice to achieve energy efficiency with significant results in some cases.

  13. Absorber and emitter for solar thermo-photovoltaic systems to achieve efficiency exceeding the Shockley-Queisser limit.

    PubMed

    Rephaeli, Eden; Fan, Shanhui

    2009-08-17

    We present theoretical considerations as well as detailed numerical design of absorber and emitter for Solar Thermophotovoltaics (STPV) applications. The absorber, consisting of an array of tungsten pyramids, was designed to provide near-unity absorptivity over all solar wavelengths for a wide angular range, enabling it to absorb light effectively from solar sources regardless of concentration. The emitter, a tungsten slab with Si/SiO(2) multilayer stack, provides a sharp emissivity peak at the solar cell band-gap while suppressing emission at lower frequencies. We show that, under a suitable light concentration condition, and with a reasonable area ratio between the emitter and absorber, a STPV system employing such absorber-emitter pair and a single-junction solar cell can attain efficiency that exceeds the Shockley-Queisser limit.

  14. How endogenous plant cell-wall degradation mechanisms can help achieve higher efficiency in saccharification of biomass.

    PubMed

    Tavares, Eveline Q P; De Souza, Amanda P; Buckeridge, Marcos S

    2015-07-01

    Cell-wall recalcitrance to hydrolysis still represents one of the major bottlenecks for second-generation bioethanol production. This occurs despite the development of pre-treatments, the prospect of new enzymes, and the production of transgenic plants with less-recalcitrant cell walls. Recalcitrance, which is the intrinsic resistance to breakdown imposed by polymer assembly, is the result of inherent limitations in its three domains. These consist of: (i) porosity, associated with a pectin matrix impairing trafficking through the wall; (ii) the glycomic code, which refers to the fine-structural emergent complexity of cell-wall polymers that are unique to cells, tissues, and species; and (iii) cellulose crystallinity, which refers to the organization in micro- and/or macrofibrils. One way to circumvent recalcitrance could be by following cell-wall hydrolysis strategies underlying plant endogenous mechanisms that are optimized to precisely modify cell walls in planta. Thus, the cell-wall degradation that occurs during fruit ripening, abscission, storage cell-wall mobilization, and aerenchyma formation are reviewed in order to highlight how plants deal with recalcitrance and which are the routes to couple prospective enzymes and cocktail designs with cell-wall features. The manipulation of key enzyme levels in planta can help achieving biologically pre-treated walls (i.e. less recalcitrant) before plants are harvested for bioethanol production. This may be helpful in decreasing the costs associated with producing bioethanol from biomass.

  15. Exciplex-triplet energy transfer: A new method to achieve extremely efficient organic light-emitting diode with external quantum efficiency over 30% and drive voltage below 3 V

    NASA Astrophysics Data System (ADS)

    Seo, Satoshi; Shitagaki, Satoko; Ohsawa, Nobuharu; Inoue, Hideko; Suzuki, Kunihiko; Nowatari, Hiromi; Yamazaki, Shunpei

    2014-04-01

    A novel approach to enhance the power efficiency of an organic light-emitting diode (OLED) by employing energy transfer from an exciplex to a phosphorescent emitter is reported. It was found that excitation energy of an exciplex formed between an electron-transporting material with a π-deficient quinoxaline moiety and a hole-transporting material with aromatic amine structure can be effectively transferred to a phosphorescent iridium complex in an emission layer of a phosphorescent OLED. Moreover, such an exciplex formation increases quantum efficiency and reduces drive voltage. A highly efficient, low-voltage, and long-life OLED based on this energy transfer is also demonstrated. This OLED device exhibited extremely high external quantum efficiency of 31% even without any attempt to enhance light outcoupling and also achieved a low drive voltage of 2.8 V and a long lifetime of approximately 1,000,000 h at a luminance of 1,000 cd/m2.

  16. Enhanced Conversion Efficiencies in Dye-Sensitized Solar Cells Achieved through Self-Assembled Platinum(II) Metallacages

    NASA Astrophysics Data System (ADS)

    He, Zuoli; Hou, Zhiqiang; Xing, Yonglei; Liu, Xiaobin; Yin, Xingtian; Que, Meidan; Shao, Jinyou; Que, Wenxiu; Stang, Peter J.

    2016-07-01

    Two-component self-assembly supramolecular coordination complexes with particular photo-physical property, wherein unique donors are combined with a single metal acceptor, can be utilized for many applications including in photo-devices. In this communication, we described the synthesis and characterization of two-component self-assembly supramolecular coordination complexes (SCCs) bearing triazine and porphyrin faces with promising light-harvesting properties. These complexes were obtained from the self-assembly of a 90° Pt(II) acceptor with 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPyT) or 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). The greatly improved conversion efficiencies of the dye-sensitized TiO2 solar cells were 6.79 and 6.08 respectively, while these SCCs were introduced into the TiO2 nanoparticle film photoanodes. In addition, the open circuit voltage (Voc) of dye-sensitized solar cells was also increased to 0.769 and 0.768 V, which could be ascribed to the inhibited interfacial charge recombination due to the addition of SCCs.

  17. Achieving High Efficiency and Eliminating Degradation in Solid Oxide Electrochemical Cells Using High Oxygen-Capacity Perovskite.

    PubMed

    Jun, Areum; Kim, Junyoung; Shin, Jeeyoung; Kim, Guntae

    2016-09-26

    Recently, there have been efforts to use clean and renewable energy because of finite fossil fuels and environmental problems. Owing to the site-specific and weather-dependent characteristics of the renewable energy supply, solid oxide electrolysis cells (SOECs) have received considerable attention to store energy as hydrogen. Conventional SOECs use Ni-YSZ (yttria-stabilized zirconia) and LSM (strontium-doped lanthanum manganites)-YSZ as electrodes. These electrodes, however, suffer from redox-instability and coarsening of the Ni electrode along with delamination of the LSM electrode during steam electrolysis. In this study, we successfully design and fabricate highly efficient SOECs using layered perovskites, PrBaMn2 O5+δ (PBM) and PrBa0.5 Sr0.5 Co1.5 Fe0.5 O5+δ (PBSCF50), as both electrodes for the first time. The SOEC with layered perovskites as both-side electrodes shows outstanding performance, reversible cycling, and remarkable stability over 600 hours. PMID:27604172

  18. Achieving High Efficiency and Eliminating Degradation in Solid Oxide Electrochemical Cells Using High Oxygen-Capacity Perovskite.

    PubMed

    Jun, Areum; Kim, Junyoung; Shin, Jeeyoung; Kim, Guntae

    2016-09-26

    Recently, there have been efforts to use clean and renewable energy because of finite fossil fuels and environmental problems. Owing to the site-specific and weather-dependent characteristics of the renewable energy supply, solid oxide electrolysis cells (SOECs) have received considerable attention to store energy as hydrogen. Conventional SOECs use Ni-YSZ (yttria-stabilized zirconia) and LSM (strontium-doped lanthanum manganites)-YSZ as electrodes. These electrodes, however, suffer from redox-instability and coarsening of the Ni electrode along with delamination of the LSM electrode during steam electrolysis. In this study, we successfully design and fabricate highly efficient SOECs using layered perovskites, PrBaMn2 O5+δ (PBM) and PrBa0.5 Sr0.5 Co1.5 Fe0.5 O5+δ (PBSCF50), as both electrodes for the first time. The SOEC with layered perovskites as both-side electrodes shows outstanding performance, reversible cycling, and remarkable stability over 600 hours.

  19. An approach for an advanced anode interfacial layer with electron-blocking ability to achieve high-efficiency organic photovoltaics.

    PubMed

    Yeo, Jun-Seok; Yun, Jin-Mun; Kang, Minji; Khim, Dongyoon; Lee, Seung-Hoon; Kim, Seok-Soon; Na, Seok-In; Kim, Dong-Yu

    2014-11-26

    The interfacial properties of PEDOT:PSS, pristine r-GO, and r-GO with sulfonic acid (SR-GO) in organic photovoltaic are investigated to elucidate electron-blocking property of PEDOT:PSS anode interfacial layer (AIL), and to explore the possibility of r-GO as electron-blocking layers. The SR-GO results in an optimized power conversion efficiency of 7.54% for PTB7-th:PC71BM and 5.64% for P3HT:IC61BA systems. By combining analyses of capacitance-voltage and photovoltaic-parameters dependence on light intensity, it is found that recombination process at SR-GO/active film is minimized. In contrast, the devices using r-GO without sulfonic acid show trap-assisted recombination. The enhanced electron-blocking properties in PEDOT:PSS and SR-GO AILs can be attributed to surface dipoles at AIL/acceptor. Thus, for electron-blocking, the AIL/acceptor interface should be importantly considered in OPVs. Also, by simply introducing sulfonic acid unit on r-GO, excellent contact selectivity can be realized in OPVs.

  20. Enhanced Conversion Efficiencies in Dye-Sensitized Solar Cells Achieved through Self-Assembled Platinum(II) Metallacages

    PubMed Central

    He, Zuoli; Hou, Zhiqiang; Xing, Yonglei; Liu, Xiaobin; Yin, Xingtian; Que, Meidan; Shao, Jinyou; Que, Wenxiu; Stang, Peter J.

    2016-01-01

    Two-component self-assembly supramolecular coordination complexes with particular photo-physical property, wherein unique donors are combined with a single metal acceptor, can be utilized for many applications including in photo-devices. In this communication, we described the synthesis and characterization of two-component self-assembly supramolecular coordination complexes (SCCs) bearing triazine and porphyrin faces with promising light-harvesting properties. These complexes were obtained from the self-assembly of a 90° Pt(II) acceptor with 2,4,6-tris(4-pyridyl)-1,3,5-triazine (TPyT) or 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine (TPyP). The greatly improved conversion efficiencies of the dye-sensitized TiO2 solar cells were 6.79 and 6.08 respectively, while these SCCs were introduced into the TiO2 nanoparticle film photoanodes. In addition, the open circuit voltage (Voc) of dye-sensitized solar cells was also increased to 0.769 and 0.768 V, which could be ascribed to the inhibited interfacial charge recombination due to the addition of SCCs. PMID:27404912

  1. Implementation of a compressive sampling scheme for wireless sensors to achieve energy efficiency in a structural health monitoring system

    NASA Astrophysics Data System (ADS)

    O'Connor, Sean M.; Lynch, Jerome P.; Gilbert, Anna C.

    2013-04-01

    Wireless sensors have emerged to offer low-cost sensors with impressive functionality (e.g., data acquisition, computing, and communication) and modular installations. Such advantages enable higher nodal densities than tethered systems resulting in increased spatial resolution of the monitoring system. However, high nodal density comes at a cost as huge amounts of data are generated, weighing heavy on power sources, transmission bandwidth, and data management requirements, often making data compression necessary. The traditional compression paradigm consists of high rate (>Nyquist) uniform sampling and storage of the entire target signal followed by some desired compression scheme prior to transmission. The recently proposed compressed sensing (CS) framework combines the acquisition and compression stage together, thus removing the need for storage and operation of the full target signal prior to transmission. The effectiveness of the CS approach hinges on the presence of a sparse representation of the target signal in a known basis, similarly exploited by several traditional compressive sensing applications today (e.g., imaging, MRI). Field implementations of CS schemes in wireless SHM systems have been challenging due to the lack of commercially available sensing units capable of sampling methods (e.g., random) consistent with the compressed sensing framework, often moving evaluation of CS techniques to simulation and post-processing. The research presented here describes implementation of a CS sampling scheme to the Narada wireless sensing node and the energy efficiencies observed in the deployed sensors. Of interest in this study is the compressibility of acceleration response signals collected from a multi-girder steel-concrete composite bridge. The study shows the benefit of CS in reducing data requirements while ensuring data analysis on compressed data remain accurate.

  2. Efficient, high-brightness wavelength-beam-combined commercial off-the-shelf diode stacks achieved by use of a wavelength-chirped volume Bragg grating.

    PubMed

    Chann, B; Goyal, A K; Fan, T Y; Sanchez-Rubio, A; Volodin, B L; Ban, V S

    2006-05-01

    We report a method of scaling the spatial brightness from commercial off-the-shelf diode laser stacks through wavelength beam combining, by use of a linearly wavelength-chirped volume Bragg grating (VBG). Using a three-bar commercial stack of broad-area lasers and a VBG, we demonstrate 89.5 W cw of beam-combined output with a beam-combining efficiency of 75%. The output beam has a propagation factor M2 approximately 26 on the slow axis and M2 approximately 21 on the fast axis. This corresponds to a brightness of approximately 20 MW/cm2 sr. To our knowledge, this is the highest brightness broad-area diode laser system. We achieve 81% coupling efficiency into a 100 microm, 0.22 N.A. fiber.

  3. Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells.

    PubMed

    Yang, Wenxing; Vlachopoulos, Nick; Hao, Yan; Hagfeldt, Anders; Boschloo, Gerrit

    2015-06-28

    Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E(0) = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only ∼0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO(+) redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be ∼0.5 μm, which is smaller than the ∼2.8 μm found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields.

  4. Efficient dye regeneration at low driving force achieved in triphenylamine dye LEG4 and TEMPO redox mediator based dye-sensitized solar cells.

    PubMed

    Yang, Wenxing; Vlachopoulos, Nick; Hao, Yan; Hagfeldt, Anders; Boschloo, Gerrit

    2015-06-28

    Minimizing the driving force required for the regeneration of oxidized dyes using redox mediators in an electrolyte is essential to further improve the open-circuit voltage and efficiency of dye-sensitized solar cells (DSSCs). Appropriate combinations of redox mediators and dye molecules should be explored to achieve this goal. Herein, we present a triphenylamine dye, LEG4, in combination with a TEMPO-based electrolyte in acetonitrile (E(0) = 0.89 V vs. NHE), reaching an efficiency of up to 5.4% under one sun illumination and 40% performance improvement compared to the previously and widely used indoline dye D149. The origin of this improvement was found to be the increased dye regeneration efficiency of LEG4 using the TEMPO redox mediator, which regenerated more than 80% of the oxidized dye with a driving force of only ∼0.2 eV. Detailed mechanistic studies further revealed that in addition to electron recombination to oxidized dyes, recombination of electrons from the conducting substrate and the mesoporous TiO2 film to the TEMPO(+) redox species in the electrolyte accounts for the reduced short circuit current, compared to the state-of-the-art cobalt tris(bipyridine) electrolyte system. The diffusion length of the TEMPO-electrolyte based DSSCs was determined to be ∼0.5 μm, which is smaller than the ∼2.8 μm found for cobalt-electrolyte based DSSCs. These results show the advantages of using LEG4 as a sensitizer, compared to previously record indoline dyes, in combination with a TEMPO-based electrolyte. The low driving force for efficient dye regeneration presented by these results shows the potential to further improve the power conversion efficiency (PCE) of DSSCs by utilizing redox couples and dyes with a minimal need of driving force for high regeneration yields. PMID:26016854

  5. Impact of 5-aminolevulinic acid with iron supplementation on exercise efficiency and home-based walking training achievement in older women.

    PubMed

    Masuki, Shizue; Morita, Atsumi; Kamijo, Yoshi-ichiro; Ikegawa, Shigeki; Kataoka, Yufuko; Ogawa, Yu; Sumiyoshi, Eri; Takahashi, Kiwamu; Tanaka, Tohru; Nakajima, Motowo; Nose, Hiroshi

    2016-01-01

    A reduction in exercise efficiency with aging limits daily living activities. We examined whether 5-aminolevulinic acid (ALA) with sodium ferrous citrate (SFC) increased exercise efficiency and voluntary achievement of interval walking training (IWT) in older women. Ten women [65 ± 3(SD) yr] who had performed IWT for >12 mo and were currently performing IWT participated in this study. The study was conducted in a placebo-controlled, double-blind crossover design. All subjects underwent two trials for 7 days each in which they performed IWT with ALA+SFC (100 and 115 mg/day, respectively) or placebo supplement intake (CNT), intermittently with a 2-wk washout period. Before and after each trial, subjects underwent a graded cycling test at 27.0 °C atmospheric temperature and 50% relative humidity, and oxygen consumption rate, carbon dioxide production rate, and lactate concentration in plasma were measured. Furthermore, for the first 6 days of each trial, exercise intensity for IWT was measured by accelerometry. We found that, in the ALA+SFC trial, oxygen consumption rate and carbon dioxide production rate during graded cycling decreased by 12% (P < 0.001) and 11% (P = 0.001) at every workload, respectively, accompanied by a 16% reduction in lactate concentration in plasma (P < 0.001), although all remained unchanged in the CNT trial (P > 0.2). All of the reductions were significantly greater in the ALA+SFC than the CNT trial (P < 0.05). Furthermore, the training days, impulse, and time at fast walking were 42% (P = 0.028), 102% (P = 0.027), and 69% (P = 0.039) higher during the ALA+SFC than the CNT intake period, respectively. Thus ALA+SFC supplementation augmented exercise efficiency and thereby improved IWT achievement in older women.

  6. Impact of 5-aminolevulinic acid with iron supplementation on exercise efficiency and home-based walking training achievement in older women

    PubMed Central

    Masuki, Shizue; Morita, Atsumi; Kamijo, Yoshi-ichiro; Ikegawa, Shigeki; Kataoka, Yufuko; Ogawa, Yu; Sumiyoshi, Eri; Takahashi, Kiwamu; Tanaka, Tohru; Nakajima, Motowo

    2015-01-01

    A reduction in exercise efficiency with aging limits daily living activities. We examined whether 5-aminolevulinic acid (ALA) with sodium ferrous citrate (SFC) increased exercise efficiency and voluntary achievement of interval walking training (IWT) in older women. Ten women [65 ± 3(SD) yr] who had performed IWT for >12 mo and were currently performing IWT participated in this study. The study was conducted in a placebo-controlled, double-blind crossover design. All subjects underwent two trials for 7 days each in which they performed IWT with ALA+SFC (100 and 115 mg/day, respectively) or placebo supplement intake (CNT), intermittently with a 2-wk washout period. Before and after each trial, subjects underwent a graded cycling test at 27.0°C atmospheric temperature and 50% relative humidity, and oxygen consumption rate, carbon dioxide production rate, and lactate concentration in plasma were measured. Furthermore, for the first 6 days of each trial, exercise intensity for IWT was measured by accelerometry. We found that, in the ALA+SFC trial, oxygen consumption rate and carbon dioxide production rate during graded cycling decreased by 12% (P < 0.001) and 11% (P = 0.001) at every workload, respectively, accompanied by a 16% reduction in lactate concentration in plasma (P < 0.001), although all remained unchanged in the CNT trial (P > 0.2). All of the reductions were significantly greater in the ALA+SFC than the CNT trial (P < 0.05). Furthermore, the training days, impulse, and time at fast walking were 42% (P = 0.028), 102% (P = 0.027), and 69% (P = 0.039) higher during the ALA+SFC than the CNT intake period, respectively. Thus ALA+SFC supplementation augmented exercise efficiency and thereby improved IWT achievement in older women. PMID:26514619

  7. Highly Functional TNTs with Superb Photocatalytic, Optical, and Electronic Performance Achieving Record PV Efficiency of 10.1% for 1D-Based DSSCs.

    PubMed

    Qadir, Muhammad Bilal; Li, Yuewen; Sahito, Iftikhar Ali; Arbab, Alvira Ayoub; Sun, Kyung Chul; Mengal, Naveed; Memon, Anam Ali; Jeong, Sung Hoon

    2016-09-01

    Different nanostructures of TiO2 play an important role in the photocatalytic and photoelectronic applications. TiO2 nanotubes (TNTs) have received increasing attention for these applications due to their unique physicochemical properties. Focusing on highly functional TNTs (HF-TNTs) for photocatalytic and photoelectronic applications, this study describes the facile hydrothermal synthesis of HF-TNTs by using commercial and cheaper materials for cost-effective manufacturing. To prove the functionality and applicability, these TNTs are used as scattering structure in dye-sensitized solar cells (DSSCs). Photocatalytic, optical, Brunauer-Emmett-Teller (BET), electrochemical impedance spectrum, incident-photon-to-current efficiency, and intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy characterizations are proving the functionality of HF-TNTs for DSSCs. HF-TNTs show 50% higher photocatalytic degradation rate and also 68% higher dye loading ability than conventional TNTs (C-TNTs). The DSSCs having HF-TNT and its composite-based multifunctional overlayer show effective light absorption, outstanding light scattering, lower interfacial resistance, longer electron lifetime, rapid electron transfer, and improved diffusion length, and consequently, J SC , quantum efficiency, and record photoconversion efficiency of 10.1% using commercial N-719 dye is achieved, for 1D-based DSSCs. These new and highly functional TNTs will be a concrete fundamental background toward the development of more functional applications in fuel cells, dye-sensitized solar cells, Li-ion batteries, photocatalysis process, ion-exchange/adsorption process, and photoelectrochemical devices. PMID:27432775

  8. Simple combination of oxidants with zero-valent-iron (ZVI) achieved very rapid and highly efficient removal of heavy metals from water.

    PubMed

    Guo, Xuejun; Yang, Zhe; Dong, Haiyang; Guan, Xiaohong; Ren, Qidong; Lv, Xiaofang; Jin, Xin

    2016-01-01

    This study, for the first time, demonstrated a continuously accelerated Fe(0) corrosion driven by common oxidants (i.e., NaClO, KMnO4 or H2O2) and thereby the rapid and efficient removal of heavy metals (HMs) by zero-valent iron (ZVI) under the experimental conditions of jar tests and column running. ZVI simply coupled with NaClO, KMnO4 or H2O2 (0.5 mM) resulted in almost complete As(V) removal within only 10 min with 1000 μg/L of initial As(V) at initial pH of 7.5(±0.1) and liquid solid ratio of 200:1. Simultaneous removal of 200 μg/L of initial Cd(II) and Hg(II) to 2.4-4.4 μg/L for Cd(II) and to 4.0-5.0 μg/L for Hg(II) were achieved within 30 min. No deterioration of HM removal was observed during the ten recycles of jar tests. The ZVI columns activated by 0.1 mM of oxidants had stably treated 40,200 (NaClO), 20,295 (KMnO4) and 40,200 (H2O2) bed volumes (BV) of HM-contaminated drinking water, but with no any indication of As breakthrough (<10 μg/L) even at short empty bed contact time (EBCT) of 8.0 min. The high efficiency of HMs removal from both the jar tests and column running implied a continuous and stable activation (overcoming of iron passivation) of Fe(0) surface by the oxidants. Via the proper increase in oxidant dosing, the ZVI/oxidant combination was applicable to treat highly As(V)-contaminated wastewater. During Fe(0) surface corrosion accelerated by oxidants, a large amount of fresh and reactive iron oxides and oxyhydroxides were continuously generated, which were responsible for the rapid and efficient removal of HMs through multiple mechanisms including adsorption and co-precipitation. A steady state of Fe(0) surface activation and HM removal enabled this simply coupled system to remove HMs with high speed, efficiency and perdurability. PMID:26575476

  9. Simple combination of oxidants with zero-valent-iron (ZVI) achieved very rapid and highly efficient removal of heavy metals from water.

    PubMed

    Guo, Xuejun; Yang, Zhe; Dong, Haiyang; Guan, Xiaohong; Ren, Qidong; Lv, Xiaofang; Jin, Xin

    2016-01-01

    This study, for the first time, demonstrated a continuously accelerated Fe(0) corrosion driven by common oxidants (i.e., NaClO, KMnO4 or H2O2) and thereby the rapid and efficient removal of heavy metals (HMs) by zero-valent iron (ZVI) under the experimental conditions of jar tests and column running. ZVI simply coupled with NaClO, KMnO4 or H2O2 (0.5 mM) resulted in almost complete As(V) removal within only 10 min with 1000 μg/L of initial As(V) at initial pH of 7.5(±0.1) and liquid solid ratio of 200:1. Simultaneous removal of 200 μg/L of initial Cd(II) and Hg(II) to 2.4-4.4 μg/L for Cd(II) and to 4.0-5.0 μg/L for Hg(II) were achieved within 30 min. No deterioration of HM removal was observed during the ten recycles of jar tests. The ZVI columns activated by 0.1 mM of oxidants had stably treated 40,200 (NaClO), 20,295 (KMnO4) and 40,200 (H2O2) bed volumes (BV) of HM-contaminated drinking water, but with no any indication of As breakthrough (<10 μg/L) even at short empty bed contact time (EBCT) of 8.0 min. The high efficiency of HMs removal from both the jar tests and column running implied a continuous and stable activation (overcoming of iron passivation) of Fe(0) surface by the oxidants. Via the proper increase in oxidant dosing, the ZVI/oxidant combination was applicable to treat highly As(V)-contaminated wastewater. During Fe(0) surface corrosion accelerated by oxidants, a large amount of fresh and reactive iron oxides and oxyhydroxides were continuously generated, which were responsible for the rapid and efficient removal of HMs through multiple mechanisms including adsorption and co-precipitation. A steady state of Fe(0) surface activation and HM removal enabled this simply coupled system to remove HMs with high speed, efficiency and perdurability.

  10. Maximum thrust mode evaluation

    NASA Technical Reports Server (NTRS)

    Orme, John S.; Nobbs, Steven G.

    1995-01-01

    Measured reductions in acceleration times which resulted from the application of the F-15 performance seeking control (PSC) maximum thrust mode during the dual-engine test phase is presented as a function of power setting and flight condition. Data were collected at altitudes of 30,000 and 45,000 feet at military and maximum afterburning power settings. The time savings for the supersonic acceleration is less than at subsonic Mach numbers because of the increased modeling and control complexity. In addition, the propulsion system was designed to be optimized at the mid supersonic Mach number range. Recall that even though the engine is at maximum afterburner, PSC does not trim the afterburner for the maximum thrust mode. Subsonically at military power, time to accelerate from Mach 0.6 to 0.95 was cut by between 6 and 8 percent with a single engine application of PSC, and over 14 percent when both engines were optimized. At maximum afterburner, the level of thrust increases were similar in magnitude to the military power results, but because of higher thrust levels at maximum afterburner and higher aircraft drag at supersonic Mach numbers the percentage thrust increase and time to accelerate was less than for the supersonic accelerations. Savings in time to accelerate supersonically at maximum afterburner ranged from 4 to 7 percent. In general, the maximum thrust mode has performed well, demonstrating significant thrust increases at military and maximum afterburner power. Increases of up to 15 percent at typical combat-type flight conditions were identified. Thrust increases of this magnitude could be useful in a combat situation.

  11. EPA Maximum Achievable Contraction of Technocrats Act of 2013

    THOMAS, 113th Congress

    Rep. Griffith, H. Morgan [R-VA-9

    2013-12-03

    12/16/2013 Referred to the Subcommittee on Horticulture, Research, Biotechnology, and Foreign Agriculture. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  12. Lunar Farming: Achieving Maximum Yield for the Exploration of Space

    NASA Technical Reports Server (NTRS)

    Salisbury, Frank B.

    1991-01-01

    A look at what it might be like on a lunar farm in the year 2020 is provided from the point of view of the farmer. Of necessity, the farm would be a Controlled Ecological (or Environment) Life-Support System (CELSS) or a bioregenerative life-support system. Topics covered in the imaginary trip through the farm are the light, water, gasses, crops, the medium used for plantings, and the required engineering. The CELSS is designed with four functioning parts: (1) A plant-production facility with higher plants and algae; (2) food technology kitchens; (3) waste processing and recycling facilities; and (4) control systems. In many cases there is not yet enough information to be sure about matters discussed, but the exercise in imagination pinpoints a number of areas that still need considerable research to resolve the problems perceived.

  13. Practice efficiency and physician compensation: a case study.

    PubMed

    Shaw, D V

    2002-01-01

    One of the major challenges facing today's health care executive is that of achieving maximum efficiency. The public also requires an efficient health care system. However, a problem occurs when the health care executive defines "efficiency" in a manner that is diametrically opposed to the public's definition. Maximum efficiency in the physician practice is defined by productivity equal to capacity. Maximum efficiency of the health care system is defined by lower health care costs. If the physician practice is achieving its goal of maximum efficiency, the market economy will likely force a failure in achieving the public's goal of a lower cost health care system! The following case study provides an opportunity to review this health care management conundrum and offers insights into a possible approach for some solution through attention to physician compensation. PMID:12534255

  14. How Many Letters Should Preschoolers in Public Programs Know? The Diagnostic Efficiency of Various Preschool Letter-Naming Benchmarks for Predicting First-Grade Literacy Achievement

    PubMed Central

    Piasta, Shayne B.; Petscher, Yaacov; Justice, Laura M.

    2015-01-01

    Review of current federal and state standards indicates little consensus or empirical justification regarding appropriate goals, often referred to as benchmarks, for preschool letter-name learning. The present study investigated the diagnostic efficiency of various letter-naming benchmarks using a longitudinal database of 371 children who attended publicly funded preschools. Children’s uppercase and lowercase letter-naming abilities were assessed at the end of preschool, and their literacy achievement on 3 standardized measures was assessed at the end of 1st grade. Diagnostic indices (sensitivity, specificity, and negative and positive predictive power) were generated to examine the extent to which attainment of various preschool letter-naming benchmarks was associated with later risk for literacy difficulties. Results indicated generally high negative predictive power for benchmarks requiring children to know 10 or more letter names by the end of preschool. Balancing across all diagnostic indices, optimal benchmarks of 18 uppercase and 15 lowercase letter names were identified. These findings are discussed in terms of educational implications, limitations, and future directions. PMID:26346643

  15. Habitat reclamation plan to mitigate for the loss of habitat due to oil and gas production activities under maximum efficient rate, Naval Petroleum Reserve No. 1, Kern County, California

    SciTech Connect

    Anderson, D.C.

    1994-11-01

    Activities associated with oil and gas development under the Maximum Efficiency Rate (MER) from 1975 to 2025 will disturb approximately 3,354 acres. Based on 1976 aerial photographs and using a dot grid methodology, the amount of land disturbed prior to MER is estimated to be 3,603 acres. Disturbances on Naval Petroleum Reserve No. 1 (NPR-1) were mapped using 1988 aerial photography and a geographical information system. A total of 6,079 acres were classified as disturbed as of June, 1988. The overall objective of this document is to provide specific information relating to the on-site habitat restoration program at NPRC. The specific objectives, which relate to the terms and conditions that must be met by DOE as a means of protecting the San Joaquin kit fox from incidental take are to: (1) determine the amount and location of disturbed lands on NPR-1 and the number of acres disturbed as a result of MER activities, (2) develop a long term (10 year) program to restore an equivalent on-site acres to that lost from prior project-related actions, and (3) examine alternative means to offset kit fox habitat loss.

  16. Teaching for maximum learning: The Philippine experience

    NASA Astrophysics Data System (ADS)

    Sutaria, Minda C.

    1990-06-01

    The author tells about how the achievement level of Filipono grade school children is being improved through teaching for maximum learning. To promote teaching for maximum learning, it was imperative to identify minimum learning competencies in the new curriculum for each grade level, retrain teachers for teaching for maximum learning, develop appropriate instructional materials, improve the quality of supervision of instruction, install a multi-level (national to school) testing system and redress inequities in the distribution of human and material resources. This systematic approach to solving the problem of low quality of educational outcomes has resulted in a modest but steady improvement in the achievement levels of school children.

  17. Radiation engineering of optical antennas for maximum field enhancement.

    PubMed

    Seok, Tae Joon; Jamshidi, Arash; Kim, Myungki; Dhuey, Scott; Lakhani, Amit; Choo, Hyuck; Schuck, Peter James; Cabrini, Stefano; Schwartzberg, Adam M; Bokor, Jeffrey; Yablonovitch, Eli; Wu, Ming C

    2011-07-13

    Optical antennas have generated much interest in recent years due to their ability to focus optical energy beyond the diffraction limit, benefiting a broad range of applications such as sensitive photodetection, magnetic storage, and surface-enhanced Raman spectroscopy. To achieve the maximum field enhancement for an optical antenna, parameters such as the antenna dimensions, loading conditions, and coupling efficiency have been previously studied. Here, we present a framework, based on coupled-mode theory, to achieve maximum field enhancement in optical antennas through optimization of optical antennas' radiation characteristics. We demonstrate that the optimum condition is achieved when the radiation quality factor (Q(rad)) of optical antennas is matched to their absorption quality factor (Q(abs)). We achieve this condition experimentally by fabricating the optical antennas on a dielectric (SiO(2)) coated ground plane (metal substrate) and controlling the antenna radiation through optimizing the dielectric thickness. The dielectric thickness at which the matching condition occurs is approximately half of the quarter-wavelength thickness, typically used to achieve constructive interference, and leads to ∼20% higher field enhancement relative to a quarter-wavelength thick dielectric layer.

  18. Daily energy balance in growth hormone receptor/binding protein (GHR−/−) gene-disrupted mice is achieved through an increase in dark-phase energy efficiency

    PubMed Central

    Longo, Kenneth A.; Berryman, Darlene E.; Kelder, Bruce; Charoenthongtrakul, Soratree; DiStefano, Peter S.; Geddes, Brad J.; Kopchick, John

    2009-01-01

    The goal of this study was to examine factors that contribute to energy balance in female GHR −/− mice. We measured energy intake, energy expenditure (EE), fuel utilization, body mass (Mb) changes and physical activity in 17 month-old female GHR −/− mice and their age-matched wild type littermates. The GHR −/− mice were smaller, consumed more food per unit Mb, had greater EE per unit Mb and had an increase in 24-h EE/Mb that was similar to the increase in their surface-area-to-volume ratio. Locomotor activity (LMA) was reduced in the GHR −/− mice, but the energetic cost associated with their LMA was greater than in wild type controls. Furthermore, Mb and LMA were independent explanatory covariates of most of the variance in EE, and when adjusted for Mb and LMA, the GHR −/− mice had higher EE during both the light and dark phases of the daily cycle. Respiratory quotient was lower in GHR −/− mice during the light phase, which indicated a greater utilization of lipid relative to carbohydrate in these mice. Additionally, GHR −/− mice had higher ratios of caloric intake to EE at several intervals during the dark phase, and this effect was greater and more sustained in the final three hours of the dark phase. Therefore, we conclude that GHR −/− mice are able to overcome the substantial energetic challenges of dwarfism through several mechanisms that promote stable Mb. Relative to wild type mice, the GHR −/− mice consumed more calories per unit Mb, which offset the disproportionate increase in their daily energy expenditure. While GHR −/− mice oxidized a greater proportion of lipid during the light phase in order to meet their energy requirements, they achieved greater energy efficiency and storage during the dark phase through a combination of higher energy consumption and lower LMA. PMID:19747867

  19. On the Achievable Throughput Over TVWS Sensor Networks.

    PubMed

    Caleffi, Marcello; Cacciapuoti, Angela Sara

    2016-01-01

    In this letter, we study the throughput achievable by an unlicensed sensor network operating over TV white space spectrum in presence of coexistence interference. Through the letter, we first analytically derive the achievable throughput as a function of the channel ordering. Then, we show that the problem of deriving the maximum expected throughput through exhaustive search is computationally unfeasible. Finally, we derive a computational-efficient algorithm characterized by polynomial-time complexity to compute the channel set maximizing the expected throughput and, stemming from this, we derive a closed-form expression of the maximum expected throughput. Numerical simulations validate the theoretical analysis. PMID:27043565

  20. On the Achievable Throughput Over TVWS Sensor Networks.

    PubMed

    Caleffi, Marcello; Cacciapuoti, Angela Sara

    2016-03-30

    In this letter, we study the throughput achievable by an unlicensed sensor network operating over TV white space spectrum in presence of coexistence interference. Through the letter, we first analytically derive the achievable throughput as a function of the channel ordering. Then, we show that the problem of deriving the maximum expected throughput through exhaustive search is computationally unfeasible. Finally, we derive a computational-efficient algorithm characterized by polynomial-time complexity to compute the channel set maximizing the expected throughput and, stemming from this, we derive a closed-form expression of the maximum expected throughput. Numerical simulations validate the theoretical analysis.

  1. On the Achievable Throughput Over TVWS Sensor Networks

    PubMed Central

    Caleffi, Marcello; Cacciapuoti, Angela Sara

    2016-01-01

    In this letter, we study the throughput achievable by an unlicensed sensor network operating over TV white space spectrum in presence of coexistence interference. Through the letter, we first analytically derive the achievable throughput as a function of the channel ordering. Then, we show that the problem of deriving the maximum expected throughput through exhaustive search is computationally unfeasible. Finally, we derive a computational-efficient algorithm characterized by polynomial-time complexity to compute the channel set maximizing the expected throughput and, stemming from this, we derive a closed-form expression of the maximum expected throughput. Numerical simulations validate the theoretical analysis. PMID:27043565

  2. Use of combined steam-water and organic rankine cycles for achieving better efficiency of gas turbine units and internal combustion engines

    NASA Astrophysics Data System (ADS)

    Gotovskiy, M. A.; Grinman, M. I.; Fomin, V. I.; Aref'ev, V. K.; Grigor'ev, A. A.

    2012-03-01

    Innovative concepts of recovering waste heat using low-boiling working fluids, due to which the the efficiency can be increased to 28-30%, are presented. If distributed generation of electricity or combined production of heat and electricity is implemented, the electrical efficiency can reach 58-60% and the fuel heat utilization factor, 90%.

  3. The last glacial maximum

    USGS Publications Warehouse

    Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

    2009-01-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

  4. The Last Glacial Maximum.

    PubMed

    Clark, Peter U; Dyke, Arthur S; Shakun, Jeremy D; Carlson, Anders E; Clark, Jorie; Wohlfarth, Barbara; Mitrovica, Jerry X; Hostetler, Steven W; McCabe, A Marshall

    2009-08-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level approximately 14.5 ka.

  5. Maximum predictive power and the superposition principle

    NASA Technical Reports Server (NTRS)

    Summhammer, Johann

    1994-01-01

    In quantum physics the direct observables are probabilities of events. We ask how observed probabilities must be combined to achieve what we call maximum predictive power. According to this concept the accuracy of a prediction must only depend on the number of runs whose data serve as input for the prediction. We transform each probability to an associated variable whose uncertainty interval depends only on the amount of data and strictly decreases with it. We find that for a probability which is a function of two other probabilities maximum predictive power is achieved when linearly summing their associated variables and transforming back to a probability. This recovers the quantum mechanical superposition principle.

  6. Maximum Entropy Fundamentals

    NASA Astrophysics Data System (ADS)

    Harremoeës, P.; Topsøe, F.

    2001-09-01

    In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over the development of natural

  7. The Solar Maximum observatory

    NASA Technical Reports Server (NTRS)

    Rust, D. M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots.

  8. Hydraulic Limits on Maximum Plant Transpiration

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Katul, G. G.; Palmroth, S.; Jackson, R. B.; Porporato, A. M.

    2011-12-01

    Photosynthesis occurs at the expense of water losses through transpiration. As a consequence of this basic carbon-water interaction at the leaf level, plant growth and ecosystem carbon exchanges are tightly coupled to transpiration. In this contribution, the hydraulic constraints that limit transpiration rates under well-watered conditions are examined across plant functional types and climates. The potential water flow through plants is proportional to both xylem hydraulic conductivity (which depends on plant carbon economy) and the difference in water potential between the soil and the atmosphere (the driving force that pulls water from the soil). Differently from previous works, we study how this potential flux changes with the amplitude of the driving force (i.e., we focus on xylem properties and not on stomatal regulation). Xylem hydraulic conductivity decreases as the driving force increases due to cavitation of the tissues. As a result of this negative feedback, more negative leaf (and xylem) water potentials would provide a stronger driving force for water transport, while at the same time limiting xylem hydraulic conductivity due to cavitation. Here, the leaf water potential value that allows an optimum balance between driving force and xylem conductivity is quantified, thus defining the maximum transpiration rate that can be sustained by the soil-to-leaf hydraulic system. To apply the proposed framework at the global scale, a novel database of xylem conductivity and cavitation vulnerability across plant types and biomes is developed. Conductivity and water potential at 50% cavitation are shown to be complementary (in particular between angiosperms and conifers), suggesting a tradeoff between transport efficiency and hydraulic safety. Plants from warmer and drier biomes tend to achieve larger maximum transpiration than plants growing in environments with lower atmospheric water demand. The predicted maximum transpiration and the corresponding leaf water

  9. Examining the Impact of an Integrative Method of Using Technology on Students' Achievement and Efficiency of Computer Usage and on Pedagogical Procedure in Geometry

    ERIC Educational Resources Information Center

    Gurevich, Irina; Gurev, Dvora

    2012-01-01

    In the current study we follow the development of the pedagogical procedure for the course "Constructions in Geometry" that resulted from using dynamic geometry software (DGS), where the computer became an integral part of the educational process. Furthermore, we examine the influence of integrating DGS into the course on students' achievement and…

  10. Generalized Maximum Entropy

    NASA Technical Reports Server (NTRS)

    Cheeseman, Peter; Stutz, John

    2005-01-01

    A long standing mystery in using Maximum Entropy (MaxEnt) is how to deal with constraints whose values are uncertain. This situation arises when constraint values are estimated from data, because of finite sample sizes. One approach to this problem, advocated by E.T. Jaynes [1], is to ignore this uncertainty, and treat the empirically observed values as exact. We refer to this as the classic MaxEnt approach. Classic MaxEnt gives point probabilities (subject to the given constraints), rather than probability densities. We develop an alternative approach that assumes that the uncertain constraint values are represented by a probability density {e.g: a Gaussian), and this uncertainty yields a MaxEnt posterior probability density. That is, the classic MaxEnt point probabilities are regarded as a multidimensional function of the given constraint values, and uncertainty on these values is transmitted through the MaxEnt function to give uncertainty over the MaXEnt probabilities. We illustrate this approach by explicitly calculating the generalized MaxEnt density for a simple but common case, then show how this can be extended numerically to the general case. This paper expands the generalized MaxEnt concept introduced in a previous paper [3].

  11. Maximum bow force revisited.

    PubMed

    Mores, Robert

    2016-08-01

    Schelleng [J. Acoust. Soc. Am. 53, 26-41 (1973)], Askenfelt [J. Acoust. Soc. Am. 86, 503-516 (1989)], Schumacher [J. Acoust. Soc. Am. 96, 1985-1998 (1994)], and Schoonderwaldt, Guettler, and Askenfelt [Acta Acust. Acust. 94, 604-622 (2008)] formulated-in different ways-how the maximum bow force relates to bow velocity, bow-bridge distance, string impedance, and friction coefficients. Issues of uncertainty are how to account for friction or for the rotational admittance of the strings. Related measurements at the respective transitions between regimes of Helmholtz motion and non-Helmholtz motion employ a variety of bowing machines and stringed instruments. The related findings include all necessary parameters except the friction coefficients, leaving the underlying models unconfirmed. Here, a bowing pendulum has been constructed which allows precise measurement of relevant bowing parameters, including the friction coefficients. Two cellos are measured across all strings for three different bow-bridge distances. The empirical data suggest that-taking the diverse elements of existing models as options-Schelleng's model combined with Schumacher's velocity term yields the best fit. Furthermore, the pendulum employs a bow driving mechanism with adaptive impedance which discloses that mentioned regimes are stable and transitions between them sometimes require a hysteresis on related parameters. PMID:27586745

  12. How Many Letters Should Preschoolers in Public Programs Know? The Diagnostic Efficiency of Various Preschool Letter-Naming Benchmarks for Predicting First-Grade Literacy Achievement

    ERIC Educational Resources Information Center

    Piasta, Shayne B.; Petscher, Yaacov; Justice, Laura M.

    2012-01-01

    Review of current federal and state standards indicates little consensus or empirical justification regarding appropriate goals, often referred to as benchmarks, for preschool letter-name learning. The present study investigated the diagnostic efficiency of various letter-naming benchmarks using a longitudinal database of 371 children who attended…

  13. Dye-sensitized solar cells employing a single film of mesoporous TiO2 beads achieve power conversion efficiencies over 10%.

    PubMed

    Sauvage, Frédéric; Chen, Dehong; Comte, Pascal; Huang, Fuzhi; Heiniger, Leo-Philipp; Cheng, Yi-Bing; Caruso, Rachel A; Graetzel, Michael

    2010-08-24

    Dye-sensitized solar cells employing mesoporous TiO(2) beads have demonstrated longer electron diffusion lengths and extended electron lifetimes over Degussa P25 titania electrodes due to the well interconnected, densely packed nanocrystalline TiO(2) particles inside the beads. Careful selection of the dye to match the dye photon absorption characteristics with the light scattering properties of the beads have improved the light harvesting and conversion efficiency of the bead electrode in the dye-sensitized solar cell. This has resulted in a solar to electric power conversion efficiency (PCE) of greater than 10% (10.6% for Ru(II)-based dye C101 and 10.7% using C106) for the first time using a single screen-printed titania layer cell construction (that is, without an additional scattering layer).

  14. Achieving extremely concentrated aqueous dispersions of graphene flakes and catalytically efficient graphene-metal nanoparticle hybrids with flavin mononucleotide as a high-performance stabilizer.

    PubMed

    Ayán-Varela, M; Paredes, J I; Guardia, L; Villar-Rodil, S; Munuera, J M; Díaz-González, M; Fernández-Sánchez, C; Martínez-Alonso, A; Tascón, J M D

    2015-05-20

    The stable dispersion of graphene flakes in an aqueous medium is highly desirable for the development of materials based on this two-dimensional carbon structure, but current production protocols that make use of a number of surfactants typically suffer from limitations regarding graphene concentration or the amount of surfactant required to colloidally stabilize the sheets. Here, we demonstrate that an innocuous and readily available derivative of vitamin B2, namely the sodium salt of flavin mononucleotide (FMNS), is a highly efficient dispersant in the preparation of aqueous dispersions of defect-free, few-layer graphene flakes. Most notably, graphene concentrations in water as high as ∼50 mg mL(-1) using low amounts of FMNS (FMNS/graphene mass ratios of about 0.04) could be attained, which facilitated the formation of free-standing graphene films displaying high electrical conductivity (∼52000 S m(-1)) without the need of carrying out thermal annealing or other types of post-treatment. The excellent performance of FMNS as a graphene dispersant could be attributed to the combined effect of strong adsorption on the sheets through the isoalloxazine moiety of the molecule and efficient colloidal stabilization provided by its negatively charged phosphate group. The FMNS-stabilized graphene sheets could be decorated with nanoparticles of several noble metals (Ag, Pd, and Pt), and the resulting hybrids exhibited a high catalytic activity in the reduction of nitroarenes and electroreduction of oxygen. Overall, the present results should expedite the processing and implementation of graphene in, e.g., conductive inks, composites, and hybrid materials with practical utility in a wide range of applications. PMID:25915172

  15. Achieving extremely concentrated aqueous dispersions of graphene flakes and catalytically efficient graphene-metal nanoparticle hybrids with flavin mononucleotide as a high-performance stabilizer.

    PubMed

    Ayán-Varela, M; Paredes, J I; Guardia, L; Villar-Rodil, S; Munuera, J M; Díaz-González, M; Fernández-Sánchez, C; Martínez-Alonso, A; Tascón, J M D

    2015-05-20

    The stable dispersion of graphene flakes in an aqueous medium is highly desirable for the development of materials based on this two-dimensional carbon structure, but current production protocols that make use of a number of surfactants typically suffer from limitations regarding graphene concentration or the amount of surfactant required to colloidally stabilize the sheets. Here, we demonstrate that an innocuous and readily available derivative of vitamin B2, namely the sodium salt of flavin mononucleotide (FMNS), is a highly efficient dispersant in the preparation of aqueous dispersions of defect-free, few-layer graphene flakes. Most notably, graphene concentrations in water as high as ∼50 mg mL(-1) using low amounts of FMNS (FMNS/graphene mass ratios of about 0.04) could be attained, which facilitated the formation of free-standing graphene films displaying high electrical conductivity (∼52000 S m(-1)) without the need of carrying out thermal annealing or other types of post-treatment. The excellent performance of FMNS as a graphene dispersant could be attributed to the combined effect of strong adsorption on the sheets through the isoalloxazine moiety of the molecule and efficient colloidal stabilization provided by its negatively charged phosphate group. The FMNS-stabilized graphene sheets could be decorated with nanoparticles of several noble metals (Ag, Pd, and Pt), and the resulting hybrids exhibited a high catalytic activity in the reduction of nitroarenes and electroreduction of oxygen. Overall, the present results should expedite the processing and implementation of graphene in, e.g., conductive inks, composites, and hybrid materials with practical utility in a wide range of applications.

  16. Achieving significantly enhanced visible-light photocatalytic efficiency using a polyelectrolyte: the composites of exfoliated titania nanosheets, graphene, and poly(diallyl-dimethyl-ammonium chloride)

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; An, Qi; Luan, Xinglong; Huang, Hongwei; Li, Xiaowei; Meng, Zilin; Tong, Wangshu; Chen, Xiaodong; Chu, Paul K.; Zhang, Yihe

    2015-08-01

    A high-performance visible-light-active photocatalyst is prepared using the polyelectrolyte/exfoliated titania nanosheet/graphene oxide (GO) precursor by flocculation followed by calcination. The polyelectrolyte poly(diallyl-dimethyl-ammonium chloride) serves not only as an effective binder to precipitate GO and titania nanosheets, but also boosts the overall performance of the catalyst significantly. Unlike most titania nanosheet-based catalysts reported in the literature, the composite absorbs light in the UV-Vis-NIR range. Its decomposition rate of methylene blue is 98% under visible light. This novel strategy of using a polymer to enhance the catalytic performance of titania nanosheet-based catalysts affords immense potential in designing and fabricating next-generation photocatalysts with high efficiency.A high-performance visible-light-active photocatalyst is prepared using the polyelectrolyte/exfoliated titania nanosheet/graphene oxide (GO) precursor by flocculation followed by calcination. The polyelectrolyte poly(diallyl-dimethyl-ammonium chloride) serves not only as an effective binder to precipitate GO and titania nanosheets, but also boosts the overall performance of the catalyst significantly. Unlike most titania nanosheet-based catalysts reported in the literature, the composite absorbs light in the UV-Vis-NIR range. Its decomposition rate of methylene blue is 98% under visible light. This novel strategy of using a polymer to enhance the catalytic performance of titania nanosheet-based catalysts affords immense potential in designing and fabricating next-generation photocatalysts with high efficiency. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03256c

  17. The maximum drag reduction asymptote

    NASA Astrophysics Data System (ADS)

    Choueiri, George H.; Hof, Bjorn

    2015-11-01

    Addition of long chain polymers is one of the most efficient ways to reduce the drag of turbulent flows. Already very low concentration of polymers can lead to a substantial drag and upon further increase of the concentration the drag reduces until it reaches an empirically found limit, the so called maximum drag reduction (MDR) asymptote, which is independent of the type of polymer used. We here carry out a detailed experimental study of the approach to this asymptote for pipe flow. Particular attention is paid to the recently observed state of elasto-inertial turbulence (EIT) which has been reported to occur in polymer solutions at sufficiently high shear. Our results show that upon the approach to MDR Newtonian turbulence becomes marginalized (hibernation) and eventually completely disappears and is replaced by EIT. In particular, spectra of high Reynolds number MDR flows are compared to flows at high shear rates in small diameter tubes where EIT is found at Re < 100. The research leading to these results has received funding from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme (FP7/2007-2013) under REA grant agreement n° [291734].

  18. 10 CFR 435.4 - Energy efficiency performance standard.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... (incorporated by reference, see § 435.3), and (2) If life-cycle cost-effective, achieve energy consumption... reduction is not life-cycle cost-effective, the design of the proposed building shall be modified so as to achieve an energy consumption level at or better than the maximum level of energy efficiency that is...

  19. Achieving yield gains in wheat.

    PubMed

    Reynolds, Matthew; Foulkes, John; Furbank, Robert; Griffiths, Simon; King, Julie; Murchie, Erik; Parry, Martin; Slafer, Gustavo

    2012-10-01

    Wheat provides 20% of calories and protein consumed by humans. Recent genetic gains are <1% per annum (p.a.), insufficient to meet future demand. The Wheat Yield Consortium brings expertise in photosynthesis, crop adaptation and genetics to a common breeding platform. Theory suggest radiation use efficiency (RUE) of wheat could be increased ~50%; strategies include modifying specificity, catalytic rate and regulation of Rubisco, up-regulating Calvin cycle enzymes, introducing chloroplast CO(2) concentrating mechanisms, optimizing light and N distribution of canopies while minimizing photoinhibition, and increasing spike photosynthesis. Maximum yield expression will also require dynamic optimization of source: sink so that dry matter partitioning to reproductive structures is not at the cost of the roots, stems and leaves needed to maintain physiological and structural integrity. Crop development should favour spike fertility to maximize harvest index so phenology must be tailored to different photoperiods, and sensitivity to unpredictable weather must be modulated to reduce conservative responses that reduce harvest index. Strategic crossing of complementary physiological traits will be augmented with wide crossing, while genome-wide selection and high throughput phenotyping and genotyping will increase efficiency of progeny screening. To ensure investment in breeding achieves agronomic impact, sustainable crop management must also be promoted through crop improvement networks.

  20. Use of boron cluster-containing redox nanoparticles with ROS scavenging ability in boron neutron capture therapy to achieve high therapeutic efficiency and low adverse effects.

    PubMed

    Gao, Zhenyu; Horiguchi, Yukichi; Nakai, Kei; Matsumura, Akira; Suzuki, Minoru; Ono, Koji; Nagasaki, Yukio

    2016-10-01

    A boron delivery system with high therapeutic efficiency and low adverse effects is crucial for a successful boron neutron capture therapy (BNCT). In this study, we developed boron cluster-containing redox nanoparticles (BNPs) via polyion complex (PIC) formation, using a newly synthesized poly(ethylene glycol)-polyanion (PEG-polyanion, possessing a (10)B-enriched boron cluster as a side chain of one of its segments) and PEG-polycation (possessing a reactive oxygen species (ROS) scavenger as a side chain of one of its segments). The BNPs exhibited high colloidal stability, selective uptake in tumor cells, specific accumulation, and long retention in tumor tissue and ROS scavenging ability. After thermal neutron irradiation, significant suppression of tumor growth was observed in the BNP-treated group, with only 5-ppm (10)B in tumor tissues, whereas at least 20-ppm (10)B is generally required for low molecular weight (LMW) (10)B agents. In addition, increased leukocyte levels were observed in the LMW (10)B agent-treated group after thermal neutron irradiation, and not in BNP-treated group, which might be attributed to its ROS scavenging ability. No visual metastasis of tumor cells to other organs was observed 1 month after irradiation in the BNP-treated group. These results suggest that BNPs are promising for enhancing the BNCT performance. PMID:27467416

  1. Use of boron cluster-containing redox nanoparticles with ROS scavenging ability in boron neutron capture therapy to achieve high therapeutic efficiency and low adverse effects.

    PubMed

    Gao, Zhenyu; Horiguchi, Yukichi; Nakai, Kei; Matsumura, Akira; Suzuki, Minoru; Ono, Koji; Nagasaki, Yukio

    2016-10-01

    A boron delivery system with high therapeutic efficiency and low adverse effects is crucial for a successful boron neutron capture therapy (BNCT). In this study, we developed boron cluster-containing redox nanoparticles (BNPs) via polyion complex (PIC) formation, using a newly synthesized poly(ethylene glycol)-polyanion (PEG-polyanion, possessing a (10)B-enriched boron cluster as a side chain of one of its segments) and PEG-polycation (possessing a reactive oxygen species (ROS) scavenger as a side chain of one of its segments). The BNPs exhibited high colloidal stability, selective uptake in tumor cells, specific accumulation, and long retention in tumor tissue and ROS scavenging ability. After thermal neutron irradiation, significant suppression of tumor growth was observed in the BNP-treated group, with only 5-ppm (10)B in tumor tissues, whereas at least 20-ppm (10)B is generally required for low molecular weight (LMW) (10)B agents. In addition, increased leukocyte levels were observed in the LMW (10)B agent-treated group after thermal neutron irradiation, and not in BNP-treated group, which might be attributed to its ROS scavenging ability. No visual metastasis of tumor cells to other organs was observed 1 month after irradiation in the BNP-treated group. These results suggest that BNPs are promising for enhancing the BNCT performance.

  2. Efficient reinforcement learning of a reservoir network model of parametric working memory achieved with a cluster population winner-take-all readout mechanism.

    PubMed

    Cheng, Zhenbo; Deng, Zhidong; Hu, Xiaolin; Zhang, Bo; Yang, Tianming

    2015-12-01

    The brain often has to make decisions based on information stored in working memory, but the neural circuitry underlying working memory is not fully understood. Many theoretical efforts have been focused on modeling the persistent delay period activity in the prefrontal areas that is believed to represent working memory. Recent experiments reveal that the delay period activity in the prefrontal cortex is neither static nor homogeneous as previously assumed. Models based on reservoir networks have been proposed to model such a dynamical activity pattern. The connections between neurons within a reservoir are random and do not require explicit tuning. Information storage does not depend on the stable states of the network. However, it is not clear how the encoded information can be retrieved for decision making with a biologically realistic algorithm. We therefore built a reservoir-based neural network to model the neuronal responses of the prefrontal cortex in a somatosensory delayed discrimination task. We first illustrate that the neurons in the reservoir exhibit a heterogeneous and dynamical delay period activity observed in previous experiments. Then we show that a cluster population circuit decodes the information from the reservoir with a winner-take-all mechanism and contributes to the decision making. Finally, we show that the model achieves a good performance rapidly by shaping only the readout with reinforcement learning. Our model reproduces important features of previous behavior and neurophysiology data. We illustrate for the first time how task-specific information stored in a reservoir network can be retrieved with a biologically plausible reinforcement learning training scheme.

  3. Evaluating Opportunities for Achieving Cost Efficiencies Through the Introduction of PrePex Device Male Circumcision in Adult VMMC Programs in Zambia and Zimbabwe

    PubMed Central

    Chintu, Naminga; Yano, Nanako; Mugurungi, Owen; Tambatamba, Bushimbwa; Ncube, Gertrude; Xaba, Sinokuthemba; Mpasela, Felton; Muguza, Edward; Mangono, Tichakunda; Madidi, Ngonidzashe; Samona, Alick; Tagar, Elva; Hatzold, Karin

    2016-01-01

    Background: Results from recent costing studies have put into question potential Voluntary Medical Male Circumcision (VMMC) cost savings with the introduction of the PrePex device. Methods: We evaluated the cost drivers and the overall unit cost of VMMC for a variety of service delivery models providing either surgical VMMC or both PrePex and surgery using current program data in Zimbabwe and Zambia. In Zimbabwe, 3 hypothetical PrePex only models were also included. For all models, clients aged 18 years and older were assumed to be medically eligible for PrePex and uptake was based on current program data from sites providing both methods. Direct costs included costs for consumables, including surgical VMMC kits for the forceps-guided method, device (US $12), human resources, demand creation, supply chain, waste management, training, and transport. Results: Results for both countries suggest limited potential for PrePex to generate cost savings when adding the device to current surgical service delivery models. However, results for the hypothetical rural Integrated PrePex model in Zimbabwe suggest the potential for material unit cost savings (US $35 per VMMC vs. US $65–69 for existing surgical models). Conclusions: This analysis illustrates that models designed to leverage PrePex's advantages, namely the potential for integrating services in rural clinics and less stringent infrastructure requirements, may present opportunities for improved cost efficiency and service integration. Countries seeking to scale up VMMC in rural settings might consider integrating PrePex only MC services at the primary health care level to reduce costs while also increasing VMMC access and coverage. PMID:27331598

  4. Minimizing the probable maximum flood

    SciTech Connect

    Woodbury, M.S.; Pansic, N. ); Eberlein, D.T. )

    1994-06-01

    This article examines Wisconsin Electric Power Company's efforts to determine an economical way to comply with Federal Energy Regulatory Commission requirements at two hydroelectric developments on the Michigamme River. Their efforts included refinement of the area's probable maximum flood model based, in part, on a newly developed probable maximum precipitation estimate.

  5. Biological assessment of the effects of petroleum production at maximum efficient rate, Naval Petroleum Reserve No. 1 (Elk Hills), Kern County, California, on the endangered blunt-nosed leopard lizard, Gambelia silus

    SciTech Connect

    Kato, T.T.; O'Farrell, T.P.

    1986-06-01

    Surveys to determine the distribution and relative abundance of blunt-nosed leopard lizards on Naval Petroleum Reserve-1 were conducted in 1980 and 1981. In 1982 radiotelemetry and pitfall trapping techniques were used to gain additional information on the species and develop alternative methods of study. Incidental observations of blunt-nosed leopard lizards were recorded and used in the distribution information for NPR-1. DOE determined during this biological assessment that the construction projects and operational activities necessary to achieve and sustain MER have not adversely affected the blunt-nosed leopard lizard and its habitat, because only approximately 6% of the potential blunt-nosed leopard lizard habitat on NPR-1 was disturbed by construction and operational activities. DOE believes that the direct, indirect, and cumulative effects of MER will not jeopardize the continued existence of the species, because results of surveys indicated that blunt-nosed leopard lizards are mainly distributed near the periphery of Elk Hills where few petroleum developments occurred in the past and where they are unlikely to occur in the future. A policy of conducting preconstruction surveys to protect blunt-nosed leopard lizard habitat was initiated, a habitat restoration plan was developed and implemented, and administrative policies to reduce vehicle speeds, contain oil spills, restrict off-road vehicle (ORV) travel, and to prohibit public access, livestock grazing, and agricultural activities were maintained.

  6. High-efficiency high-energy Ka source for the critically-required maximum illumination of x-ray optics on Z using Z-petawatt-driven laser-breakout-afterburner accelerated ultrarelativistic electrons LDRD .

    SciTech Connect

    Sefkow, Adam B.; Bennett, Guy R.

    2010-09-01

    Under the auspices of the Science of Extreme Environments LDRD program, a <2 year theoretical- and computational-physics study was performed (LDRD Project 130805) by Guy R Bennett (formally in Center-01600) and Adam B. Sefkow (Center-01600): To investigate novel target designs by which a short-pulse, PW-class beam could create a brighter K{alpha} x-ray source than by simple, direct-laser-irradiation of a flat foil; Direct-Foil-Irradiation (DFI). The computational studies - which are still ongoing at this writing - were performed primarily on the RedStorm supercomputer at Sandia National Laboratories Albuquerque site. The motivation for a higher efficiency K{alpha} emitter was very clear: as the backlighter flux for any x-ray imaging technique on the Z accelerator increases, the signal-to-noise and signal-to-background ratios improve. This ultimately allows the imaging system to reach its full quantitative potential as a diagnostic. Depending on the particular application/experiment this would imply, for example, that the system would have reached its full design spatial resolution and thus the capability to see features that might otherwise be indiscernible with a traditional DFI-like x-ray source. This LDRD began FY09 and ended FY10.

  7. Skeleton Graph Matching vs. Maximum Weight Cliques aorta registration techniques.

    PubMed

    Czajkowska, Joanna; Feinen, C; Grzegorzek, M; Raspe, M; Wickenhöfer, R

    2015-12-01

    Vascular diseases are one of the most challenging health problems in developed countries. Past as well as ongoing research activities often focus on efficient, robust and fast aorta segmentation, and registration techniques. According to this needs our study targets an abdominal aorta registration method. The investigated algorithms make it possible to efficiently segment and register abdominal aorta in pre- and post-operative Computed Tomography (CT) data. In more detail, a registration technique using the Path Similarity Skeleton Graph Matching (PSSGM), as well as Maximum Weight Cliques (MWCs) are employed to realise the matching based on Computed Tomography data. The presented approaches make it possible to match characteristic voxels belonging to the aorta from different Computed Tomography (CT) series. It is particularly useful in the assessment of the abdominal aortic aneurysm treatment by visualising the correspondence between the pre- and post-operative CT data. The registration results have been tested on the database of 18 contrast-enhanced CT series, where the cross-registration analysis has been performed producing 153 matching examples. All the registration results achieved with our system have been verified by an expert. The carried out analysis has highlighted the advantage of the MWCs technique over the PSSGM method. The verification phase proves the efficiency of the MWCs approach and encourages to further develop this methods.

  8. Arctic Sea Ice Maximum 2011

    NASA Video Gallery

    AMSR-E Arctic Sea Ice: September 2010 to March 2011: Scientists tracking the annual maximum extent of Arctic sea ice said that 2011 was among the lowest ice extents measured since satellites began ...

  9. Principles of maximum entropy and maximum caliber in statistical physics

    NASA Astrophysics Data System (ADS)

    Pressé, Steve; Ghosh, Kingshuk; Lee, Julian; Dill, Ken A.

    2013-07-01

    The variational principles called maximum entropy (MaxEnt) and maximum caliber (MaxCal) are reviewed. MaxEnt originated in the statistical physics of Boltzmann and Gibbs, as a theoretical tool for predicting the equilibrium states of thermal systems. Later, entropy maximization was also applied to matters of information, signal transmission, and image reconstruction. Recently, since the work of Shore and Johnson, MaxEnt has been regarded as a principle that is broader than either physics or information alone. MaxEnt is a procedure that ensures that inferences drawn from stochastic data satisfy basic self-consistency requirements. The different historical justifications for the entropy S=-∑ipilog⁡pi and its corresponding variational principles are reviewed. As an illustration of the broadening purview of maximum entropy principles, maximum caliber, which is path entropy maximization applied to the trajectories of dynamical systems, is also reviewed. Examples are given in which maximum caliber is used to interpret dynamical fluctuations in biology and on the nanoscale, in single-molecule and few-particle systems such as molecular motors, chemical reactions, biological feedback circuits, and diffusion in microfluidics devices.

  10. Solar Panel System for Street Light Using Maximum Power Point Tracking (MPPT) Technique

    NASA Astrophysics Data System (ADS)

    Wiedjaja, A.; Harta, S.; Josses, L.; Winardi; Rinda, H.

    2014-03-01

    Solar energy is one form of the renewable energy which is very abundant in regions close to the equator. One application of solar energy is for street light. This research focuses on using the maximum power point tracking technique (MPPT), particularly the perturb and observe (P&O) algorithm, to charge battery for street light system. The proposed charger circuit can achieve 20.73% higher power efficiency compared to that of non-MPPT charger. We also develop the LED driver circuit for the system which can achieve power efficiency up to 91.9% at a current of 1.06 A. The proposed street lightning system can be implemented with a relatively low cost for public areas.

  11. MAXIMUM LIKELIHOOD ESTIMATION FOR SOCIAL NETWORK DYNAMICS

    PubMed Central

    Snijders, Tom A.B.; Koskinen, Johan; Schweinberger, Michael

    2014-01-01

    A model for network panel data is discussed, based on the assumption that the observed data are discrete observations of a continuous-time Markov process on the space of all directed graphs on a given node set, in which changes in tie variables are independent conditional on the current graph. The model for tie changes is parametric and designed for applications to social network analysis, where the network dynamics can be interpreted as being generated by choices made by the social actors represented by the nodes of the graph. An algorithm for calculating the Maximum Likelihood estimator is presented, based on data augmentation and stochastic approximation. An application to an evolving friendship network is given and a small simulation study is presented which suggests that for small data sets the Maximum Likelihood estimator is more efficient than the earlier proposed Method of Moments estimator. PMID:25419259

  12. Convex accelerated maximum entropy reconstruction

    NASA Astrophysics Data System (ADS)

    Worley, Bradley

    2016-04-01

    Maximum entropy (MaxEnt) spectral reconstruction methods provide a powerful framework for spectral estimation of nonuniformly sampled datasets. Many methods exist within this framework, usually defined based on the magnitude of a Lagrange multiplier in the MaxEnt objective function. An algorithm is presented here that utilizes accelerated first-order convex optimization techniques to rapidly and reliably reconstruct nonuniformly sampled NMR datasets using the principle of maximum entropy. This algorithm - called CAMERA for Convex Accelerated Maximum Entropy Reconstruction Algorithm - is a new approach to spectral reconstruction that exhibits fast, tunable convergence in both constant-aim and constant-lambda modes. A high-performance, open source NMR data processing tool is described that implements CAMERA, and brief comparisons to existing reconstruction methods are made on several example spectra.

  13. Reduced Emissions and Lower Costs: Combining Renewable Energy and Energy Efficiency into a Sustainable Energy Portfolio Standard

    SciTech Connect

    Brown, Marilyn A

    2007-01-01

    Combining renewable energy and energy efficiency in Sustainable Energy Portfolio Standards has emerged as a key state and national policy option to achieve greater levels of sustainable energy resources with maximum economic efficiency and equity. One advantage of the SEPS relative to a renewable portfolio standard or a stand-along energy efficiency resource standard is enhanced flexibility and broader options for meeting targets.

  14. Designing a sucker-rod pumping system for maximum efficiency

    SciTech Connect

    Gault, R.H.

    1987-11-01

    Consideration of the energy requirements in the design of a sucker-rod pumping system is very important. Examples are given that detail how the use of the largest possible pump with the lightest, strongest rod string and special-geometry units can provide a substantial energy reduction.

  15. Designing a sucker rod pumping system for maximum efficiency

    SciTech Connect

    Gault, R.H.

    1985-01-01

    Consideration of the energy requirements in the design of a sucker rod pumping system is very important. Examples are given which detail how the use of the largest possible pump with the lightest, strongest, rod string and special geometry units can provide a substantial energy reduction.

  16. The Maximum Density of Water.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1985-01-01

    Discusses a series of experiments performed by Thomas Hope in 1805 which show the temperature at which water has its maximum density. Early data cast into a modern form as well as guidelines and recent data collected from the author provide background for duplicating Hope's experiments in the classroom. (JN)

  17. Abolishing the maximum tension principle

    NASA Astrophysics Data System (ADS)

    Dąbrowski, Mariusz P.; Gohar, H.

    2015-09-01

    We find the series of example theories for which the relativistic limit of maximum tension Fmax =c4 / 4 G represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.

  18. Maximum entropy beam diagnostic tomography

    SciTech Connect

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs.

  19. The maximum rate of mammal evolution.

    PubMed

    Evans, Alistair R; Jones, David; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Fitzgerald, Erich M G; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica M; Uhen, Mark D

    2012-03-13

    How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.

  20. The maximum rate of mammal evolution

    NASA Astrophysics Data System (ADS)

    Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.

    2012-03-01

    How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes.

  1. The maximum rate of mammal evolution.

    PubMed

    Evans, Alistair R; Jones, David; Boyer, Alison G; Brown, James H; Costa, Daniel P; Ernest, S K Morgan; Fitzgerald, Erich M G; Fortelius, Mikael; Gittleman, John L; Hamilton, Marcus J; Harding, Larisa E; Lintulaakso, Kari; Lyons, S Kathleen; Okie, Jordan G; Saarinen, Juha J; Sibly, Richard M; Smith, Felisa A; Stephens, Patrick R; Theodor, Jessica M; Uhen, Mark D

    2012-03-13

    How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous-Paleogene (K-Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. PMID:22308461

  2. The maximum rate of mammal evolution

    PubMed Central

    Evans, Alistair R.; Jones, David; Boyer, Alison G.; Brown, James H.; Costa, Daniel P.; Ernest, S. K. Morgan; Fitzgerald, Erich M. G.; Fortelius, Mikael; Gittleman, John L.; Hamilton, Marcus J.; Harding, Larisa E.; Lintulaakso, Kari; Lyons, S. Kathleen; Okie, Jordan G.; Saarinen, Juha J.; Sibly, Richard M.; Smith, Felisa A.; Stephens, Patrick R.; Theodor, Jessica M.; Uhen, Mark D.

    2012-01-01

    How fast can a mammal evolve from the size of a mouse to the size of an elephant? Achieving such a large transformation calls for major biological reorganization. Thus, the speed at which this occurs has important implications for extensive faunal changes, including adaptive radiations and recovery from mass extinctions. To quantify the pace of large-scale evolution we developed a metric, clade maximum rate, which represents the maximum evolutionary rate of a trait within a clade. We applied this metric to body mass evolution in mammals over the last 70 million years, during which multiple large evolutionary transitions occurred in oceans and on continents and islands. Our computations suggest that it took a minimum of 1.6, 5.1, and 10 million generations for terrestrial mammal mass to increase 100-, and 1,000-, and 5,000-fold, respectively. Values for whales were down to half the length (i.e., 1.1, 3, and 5 million generations), perhaps due to the reduced mechanical constraints of living in an aquatic environment. When differences in generation time are considered, we find an exponential increase in maximum mammal body mass during the 35 million years following the Cretaceous–Paleogene (K–Pg) extinction event. Our results also indicate a basic asymmetry in macroevolution: very large decreases (such as extreme insular dwarfism) can happen at more than 10 times the rate of increases. Our findings allow more rigorous comparisons of microevolutionary and macroevolutionary patterns and processes. PMID:22308461

  3. Quantum-dot Carnot engine at maximum power.

    PubMed

    Esposito, Massimiliano; Kawai, Ryoichi; Lindenberg, Katja; Van den Broeck, Christian

    2010-04-01

    We evaluate the efficiency at maximum power of a quantum-dot Carnot heat engine. The universal values of the coefficients at the linear and quadratic order in the temperature gradient are reproduced. Curzon-Ahlborn efficiency is recovered in the limit of weak dissipation.

  4. The Testability of Maximum Magnitude

    NASA Astrophysics Data System (ADS)

    Clements, R.; Schorlemmer, D.; Gonzalez, A.; Zoeller, G.; Schneider, M.

    2012-12-01

    Recent disasters caused by earthquakes of unexpectedly large magnitude (such as Tohoku) illustrate the need for reliable assessments of the seismic hazard. Estimates of the maximum possible magnitude M at a given fault or in a particular zone are essential parameters in probabilistic seismic hazard assessment (PSHA), but their accuracy remains untested. In this study, we discuss the testability of long-term and short-term M estimates and the limitations that arise from testing such rare events. Of considerable importance is whether or not those limitations imply a lack of testability of a useful maximum magnitude estimate, and whether this should have any influence on current PSHA methodology. We use a simple extreme value theory approach to derive a probability distribution for the expected maximum magnitude in a future time interval, and we perform a sensitivity analysis on this distribution to determine if there is a reasonable avenue available for testing M estimates as they are commonly reported today: devoid of an appropriate probability distribution of their own and estimated only for infinite time (or relatively large untestable periods). Our results imply that any attempt at testing such estimates is futile, and that the distribution is highly sensitive to M estimates only under certain optimal conditions that are rarely observed in practice. In the future we suggest that PSHA modelers be brutally honest about the uncertainty of M estimates, or must find a way to decrease its influence on the estimated hazard.

  5. Analysis of the efficiency of intermediate band solar cells based on quantum dot supercrystals

    SciTech Connect

    Heshmati, S; Golmohammadi, S; Abedi, K; Taleb, H

    2014-03-28

    We have studied the influence of the quantum-dot (QD) width and the quantum-dot conduction band (QD-CB) offset on the efficiency of quantum-dot intermediate band solar cells (QD-IBSCs). Simulation results demonstrate that with increasing QD-CB offset and decreasing QD width, the maximum efficiency is achieved. (laser applications and other topics in quantum electronics)

  6. Maximum life spur gear design

    NASA Technical Reports Server (NTRS)

    Savage, M.; Mackulin, B. J.; Coe, H. H.; Coy, J. J.

    1991-01-01

    Optimization procedures allow one to design a spur gear reduction for maximum life and other end use criteria. A modified feasible directions search algorithm permits a wide variety of inequality constraints and exact design requirements to be met with low sensitivity to initial guess values. The optimization algorithm is described, and the models for gear life and performance are presented. The algorithm is compact and has been programmed for execution on a desk top computer. Two examples are presented to illustrate the method and its application.

  7. High Efficiency Solar Power via Separated Photo and Voltaic Pathways

    SciTech Connect

    Michael J. Naughton

    2009-02-17

    This project demonstrates a novel nanostructured solar cell architecture capable of achieving high efficiency levels that is relatively simple and inexpensive to manufacture. The high efficiency will be achieved by the novel structure that separates the path of the photons from the path of the generated charge carriers. In this way, the photon path can be long for maximum light absorption, while the path for carriers can be short for maximum electronic energy harvesting. The combination of maximum light absorption coupled with maximum carrier harvesting is the basis for the expected high efficiency. The project will develop high efficiency solar cell prototypes utilizing this unique nanostructured architecture. The project addresses the fundamental limitation inherent in all current solar cell designs, and which opens a pathway to development for high efficiency solar cells at low cost. Realizing this goal will result in a levelized cost of electricity in the range of 10¢/kWh, which would achieve the long-sought goal of making photovoltaic electricity cost competitive with fossil-fuel generated electricity without any governmental subsidies. This breakthrough would spur the already rapid growth in the photovoltaic industry to an explosive pace, with significant, widespread benefit to the national economy and the nation’s energy security. The initial target of the program is to develop single-junction solar cells using ultrathin amorphous silicon with the performance approaching that of single crystal silicon cells.

  8. Radiated microwave power transmission system efficiency measurements

    NASA Technical Reports Server (NTRS)

    Dickinson, R. M.; Brown, W. C.

    1975-01-01

    The measured and calculated results from determining the operating efficiencies of a laboratory version of a system for transporting electric power from one point to another via a wireless free space radiated microwave beam are reported. The system's overall end-to-end efficiency as well as intermediated conversion efficiencies were measured. The maximum achieved end-to-end dc-to-ac system efficiency was 54.18% with a probable error of + or - 0.94%. The dc-to-RF conversion efficiency was measured to be 68.87% + or - 1.0% and the RF-to-dc conversion efficiency was 78.67 + or - 1.1%. Under these conditions a dc power of 495.62 + or - 3.57 W was received with a free space transmitter antenna receiver antenna separation of 170.2 cm (67 in).

  9. Physically constrained maximum likelihood mode filtering.

    PubMed

    Papp, Joseph C; Preisig, James C; Morozov, Andrey K

    2010-04-01

    Mode filtering is most commonly implemented using the sampled mode shapes or pseudoinverse algorithms. Buck et al. [J. Acoust. Soc. Am. 103, 1813-1824 (1998)] placed these techniques in the context of a broader maximum a posteriori (MAP) framework. However, the MAP algorithm requires that the signal and noise statistics be known a priori. Adaptive array processing algorithms are candidates for improving performance without the need for a priori signal and noise statistics. A variant of the physically constrained, maximum likelihood (PCML) algorithm [A. L. Kraay and A. B. Baggeroer, IEEE Trans. Signal Process. 55, 4048-4063 (2007)] is developed for mode filtering that achieves the same performance as the MAP mode filter yet does not need a priori knowledge of the signal and noise statistics. The central innovation of this adaptive mode filter is that the received signal's sample covariance matrix, as estimated by the algorithm, is constrained to be that which can be physically realized given a modal propagation model and an appropriate noise model. Shallow water simulation results are presented showing the benefit of using the PCML method in adaptive mode filtering.

  10. Discrimination networks for maximum selection.

    PubMed

    Jain, Brijnesh J; Wysotzki, Fritz

    2004-01-01

    We construct a novel discrimination network using differentiating units for maximum selection. In contrast to traditional competitive architectures like MAXNET the discrimination network does not only signal the winning unit, but also provides information about its evidence. In particular, we show that a discrimination network converges to a stable state within finite time and derive three characteristics: intensity normalization (P1), contrast enhancement (P2), and evidential response (P3). In order to improve the accuracy of the evidential response we incorporate distributed redundancy into the network. This leads to a system which is not only robust against failure of single units and noisy data, but also enables us to sharpen the focus on the problem given in terms of a more accurate evidential response. The proposed discrimination network can be regarded as a connectionist model for competitive learning by evidence.

  11. Graded Achievement, Tested Achievement, and Validity

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Twenty-eight studies of grades, over a century, were reviewed using the argument-based approach to validity suggested by Kane as a theoretical framework. The review draws conclusions about the meaning of graded achievement, its relation to tested achievement, and changes in the construct of graded achievement over time. "Graded…

  12. Maximum Correntropy Criterion for Robust Face Recognition.

    PubMed

    He, Ran; Zheng, Wei-Shi; Hu, Bao-Gang

    2011-08-01

    In this paper, we present a sparse correntropy framework for computing robust sparse representations of face images for recognition. Compared with the state-of-the-art l(1)norm-based sparse representation classifier (SRC), which assumes that noise also has a sparse representation, our sparse algorithm is developed based on the maximum correntropy criterion, which is much more insensitive to outliers. In order to develop a more tractable and practical approach, we in particular impose nonnegativity constraint on the variables in the maximum correntropy criterion and develop a half-quadratic optimization technique to approximately maximize the objective function in an alternating way so that the complex optimization problem is reduced to learning a sparse representation through a weighted linear least squares problem with nonnegativity constraint at each iteration. Our extensive experiments demonstrate that the proposed method is more robust and efficient in dealing with the occlusion and corruption problems in face recognition as compared to the related state-of-the-art methods. In particular, it shows that the proposed method can improve both recognition accuracy and receiver operator characteristic (ROC) curves, while the computational cost is much lower than the SRC algorithms.

  13. High efficiency inorganic/organic hybrid tandem solar cells.

    PubMed

    Seo, Ji Hoon; Kim, Dong-Ho; Kwon, Se-Hun; Song, Myungkwan; Choi, Min-Seung; Ryu, Seung Yoon; Lee, Hyung Woo; Park, Yun Chang; Kwon, Jung-Dae; Nam, Kee-Seok; Jeong, Yongsoo; Kang, Jae-Wook; Kim, Chang Su

    2012-08-28

    Hybrid tandem solar cells comprising an inorganic bottom cell and an organic top cell have been designed and fabricated. The interlayer combination and thickness matching were optimized in order to increase the overall photovoltaic conversion efficiency. A maximum power conversion efficiency of 5.72% was achieved along with a V(oc) of 1.42 V, reaching as high as 92% of the sum of the subcell V(oc) values. PMID:22807214

  14. Estimating contaminant loads in rivers: An application of adjusted maximum likelihood to type 1 censored data

    USGS Publications Warehouse

    Cohn, T.A.

    2005-01-01

    This paper presents an adjusted maximum likelihood estimator (AMLE) that can be used to estimate fluvial transport of contaminants, like phosphorus, that are subject to censoring because of analytical detection limits. The AMLE is a generalization of the widely accepted minimum variance unbiased estimator (MVUE), and Monte Carlo experiments confirm that it shares essentially all of the MVUE's desirable properties, including high efficiency and negligible bias. In particular, the AMLE exhibits substantially less bias than alternative censored-data estimators such as the MLE (Tobit) or the MLE followed by a jackknife. As with the MLE and the MVUE the AMLE comes close to achieving the theoretical Frechet-Crame??r-Rao bounds on its variance. This paper also presents a statistical framework, applicable to both censored and complete data, for understanding and estimating the components of uncertainty associated with load estimates. This can serve to lower the cost and improve the efficiency of both traditional and real-time water quality monitoring.

  15. Dithering Digital Ripple Correlation Control for Photovoltaic Maximum Power Point Tracking

    SciTech Connect

    Barth, C; Pilawa-Podgurski, RCN

    2015-08-01

    This study demonstrates a new method for rapid and precise maximum power point tracking in photovoltaic (PV) applications using dithered PWM control. Constraints imposed by efficiency, cost, and component size limit the available PWM resolution of a power converter, and may in turn limit the MPP tracking efficiency of the PV system. In these scenarios, PWM dithering can be used to improve average PWM resolution. In this study, we present a control technique that uses ripple correlation control (RCC) on the dithering ripple, thereby achieving simultaneous fast tracking speed and high tracking accuracy. Moreover, the proposed method solves some of the practical challenges that have to date limited the effectiveness of RCC in solar PV applications. We present a theoretical derivation of the principles behind dithering digital ripple correlation control, as well as experimental results that show excellent tracking speed and accuracy with basic hardware requirements.

  16. Multiple Early Eocene Thermal Maximums

    NASA Astrophysics Data System (ADS)

    Roehl, U.; Zachos, J. C.; Thomas, E.; Kelly, D. C.; Donner, B.; Westerhold, T.

    2004-12-01

    Periodic dissolution horizons signifying abrupt shoaling of the lysocline and CCD are characteristic features of deep-sea sections and often attributed to Milankovitch forcing via their diagnostic frequencies. Prominent dissolution horizons also correspond to abrupt climate events, such as the Paleocene-Eocene thermal maximum (PETM), as a result of input of significant CH4 - CO2 into the ocean-atmosphere system. The question arises whether other significant dissolution horizons identified in sediments of late Paleocene and early Eocene age similar to the recently identified ELMO (Lourens et al., 2004) were formed as a result of greenhouse gas input, or whether they were related to cumulative effects of periodic changes in ocean chemistry and circulation. Here we report the discovery of a 3rd thermal maximum in early Eocene (about 52 Ma) sediments recovered from the South Atlantic during ODP Leg 208. The prominent clay layer was named the "X" event and was identified within planktonic foraminifer zone P7 and calcareous nannofossil zone CP10 at four Walvis Ridge Transect sites with a water depth range of 2000 m (Sites 1262 to 1267). Benthics assemblages are composed of small individuals, have low diversity and high dominance. Dominant taxa are Nuttallides truempyi and various abyssaminids, resembling the post PETM extinction assemblages. High-resolution bulk carbonate \\delta13C measurements of one of the more shallow Sites 1265 reveal a rapid about 0.6 per mill drop in \\delta13C and \\delta18O followed by an exponential recovery to pre-excursion \\delta13C values well known for the PETM and also observed for the ELMO. The planktonic foraminiferal \\delta13C records of Morozovella subbotina and Acaranina soldadoensis in the deepest Site 1262 show a 0.8 to 0.9 per mill drop, whereas the \\delta13C drop of benthic foraminifera Nuttallides truempyi is slightly larger (about 1 per mill). We are evaluating mechanisms for the widespread change in deep-water chemistry, its

  17. Objects of Maximum Electromagnetic Chirality

    NASA Astrophysics Data System (ADS)

    Fernandez-Corbaton, Ivan; Fruhnert, Martin; Rockstuhl, Carsten

    2016-07-01

    We introduce a definition of the electromagnetic chirality of an object and show that it has an upper bound. Reciprocal objects attain the upper bound if and only if they are transparent for all the fields of one polarization handedness (helicity). Additionally, electromagnetic duality symmetry, i.e., helicity preservation upon interaction, turns out to be a necessary condition for reciprocal objects to attain the upper bound. We use these results to provide requirements for the design of such extremal objects. The requirements can be formulated as constraints on the polarizability tensors for dipolar objects or on the material constitutive relations for continuous media. We also outline two applications for objects of maximum electromagnetic chirality: a twofold resonantly enhanced and background-free circular dichroism measurement setup, and angle-independent helicity filtering glasses. Finally, we use the theoretically obtained requirements to guide the design of a specific structure, which we then analyze numerically and discuss its performance with respect to maximal electromagnetic chirality.

  18. Maximum entropy production in daisyworld

    NASA Astrophysics Data System (ADS)

    Maunu, Haley A.; Knuth, Kevin H.

    2012-05-01

    Daisyworld was first introduced in 1983 by Watson and Lovelock as a model that illustrates how life can influence a planet's climate. These models typically involve modeling a planetary surface on which black and white daisies can grow thus influencing the local surface albedo and therefore also the temperature distribution. Since then, variations of daisyworld have been applied to study problems ranging from ecological systems to global climate. Much of the interest in daisyworld models is due to the fact that they enable one to study self-regulating systems. These models are nonlinear, and as such they exhibit sensitive dependence on initial conditions, and depending on the specifics of the model they can also exhibit feedback loops, oscillations, and chaotic behavior. Many daisyworld models are thermodynamic in nature in that they rely on heat flux and temperature gradients. However, what is not well-known is whether, or even why, a daisyworld model might settle into a maximum entropy production (MEP) state. With the aim to better understand these systems, this paper will discuss what is known about the role of MEP in daisyworld models.

  19. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  20. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  1. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  2. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Family maximum. 228.14 Section 228.14... SURVIVOR ANNUITIES The Tier I Annuity Component § 228.14 Family maximum. (a) Family maximum defined. Under... person's earnings record is limited. This limited amount is called the family maximum. The family...

  3. 25 CFR 273.4 - Policy of maximum Indian participation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Policy of maximum Indian participation. 273.4 Section 273.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR INDIAN SELF-DETERMINATION AND... achievement and satisfaction which education can and should provide. Consistent with this concept,...

  4. 25 CFR 273.4 - Policy of maximum Indian participation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Policy of maximum Indian participation. 273.4 Section 273.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR INDIAN SELF-DETERMINATION AND... achievement and satisfaction which education can and should provide. Consistent with this concept,...

  5. 25 CFR 273.4 - Policy of maximum Indian participation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Policy of maximum Indian participation. 273.4 Section 273.4 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR INDIAN SELF-DETERMINATION AND... achievement and satisfaction which education can and should provide. Consistent with this concept,...

  6. 76 FR 1504 - Pipeline Safety: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-10

    ...: Establishing Maximum Allowable Operating Pressure or Maximum Operating Pressure Using Record Evidence, and... system, especially when calculating Maximum Allowable Operating Pressure (MAOP) or Maximum Operating Pressure (MOP), and to utilize these risk analyses in the identification of appropriate assessment...

  7. Maximum entropy principal for transportation

    SciTech Connect

    Bilich, F.; Da Silva, R.

    2008-11-06

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  8. A maximum hypothesis of transpiration

    NASA Astrophysics Data System (ADS)

    Wang, Jingfeng; Bras, Rafael L.; Lerdau, Manuel; Salvucci, Guido D.

    2007-09-01

    We hypothesize that the system of liquid water in leaf tissues and the water vapor in the atmosphere tends to evolve towards a potential equilibrium as quickly as possible by maximization of the transpiration rate. We make two assumptions in formulating the transpiration rate: (1) stomatal aperture is directly controlled by guard cell turgor (or leaf water potential); (2) CO2 flux can be used as a nonparametric equivalent of stomatal conductance for a given stomatal function (not necessarily optimal in terms of the water use efficiency for photosynthesis). Transpiration is then expressed as a function of leaf temperature, CO2 flux (as a surrogate of stomatal conductance), and sensible heat flux characterizing the transport mechanism at a given level of radiative energy input. Maximization of transpiration constrained by the energy balance equation leads to vanishing derivatives of transpiration with respect to leaf temperature and CO2 flux. We have obtained observational evidence in support of the proposed hypothesis.

  9. High-Efficiency Blue Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence from Phenoxaphosphine and Phenoxathiin Derivatives.

    PubMed

    Lee, Sae Youn; Adachi, Chihaya; Yasuda, Takuma

    2016-06-01

    High-efficiency blue thermally activated delayed fluorescence (TADF) molecules, consisting of phenoxaphosphine oxide and phenoxathiin dioxide as acceptor units and 9,9-dimethylacridan as a donor unit, are reported. Maximum external electroluminescence quantum efficiencies of up to 20.5% are achieved in blue organic light-emitting diodes (OLEDs) by employing these materials as TADF emitters.

  10. Maximum Parsimony on Phylogenetic networks

    PubMed Central

    2012-01-01

    Background Phylogenetic networks are generalizations of phylogenetic trees, that are used to model evolutionary events in various contexts. Several different methods and criteria have been introduced for reconstructing phylogenetic trees. Maximum Parsimony is a character-based approach that infers a phylogenetic tree by minimizing the total number of evolutionary steps required to explain a given set of data assigned on the leaves. Exact solutions for optimizing parsimony scores on phylogenetic trees have been introduced in the past. Results In this paper, we define the parsimony score on networks as the sum of the substitution costs along all the edges of the network; and show that certain well-known algorithms that calculate the optimum parsimony score on trees, such as Sankoff and Fitch algorithms extend naturally for networks, barring conflicting assignments at the reticulate vertices. We provide heuristics for finding the optimum parsimony scores on networks. Our algorithms can be applied for any cost matrix that may contain unequal substitution costs of transforming between different characters along different edges of the network. We analyzed this for experimental data on 10 leaves or fewer with at most 2 reticulations and found that for almost all networks, the bounds returned by the heuristics matched with the exhaustively determined optimum parsimony scores. Conclusion The parsimony score we define here does not directly reflect the cost of the best tree in the network that displays the evolution of the character. However, when searching for the most parsimonious network that describes a collection of characters, it becomes necessary to add additional cost considerations to prefer simpler structures, such as trees over networks. The parsimony score on a network that we describe here takes into account the substitution costs along the additional edges incident on each reticulate vertex, in addition to the substitution costs along the other edges which are

  11. Hydraulic efficiency of a hydrostatic transmission with a variable displacement pump and motor

    NASA Astrophysics Data System (ADS)

    Coombs, Daniel

    Pumps and motors are commonly connected hydraulically to create hydrostatic drives, also known as hydrostatic transmissions. A typical hydrostatic transmission consists of a variable displacement pump and a fixed displacement motor. Maximum efficiency is typically created for the system when the motor operates at maximum volumetric displacement. The objective of this research is to determine if a hydrostatic transmission with a variable displacement motor can be more efficient than one with a fixed displacement motor. A work cycle for a Caterpillar 320D excavator was created and the efficiency of the hydrostatic drive system, controlling the swing circuit, with a fixed displacement motor was compared to the efficiency with a variable displacement motor. Both multiplicative and additive uncertainty analysis were performed to determine uncertainty models that could be used to analyze the robustness of the system with feedback control applied. A PID and an H∞ controller were designed for a position control model, as well as velocity control. It was found that while it may seem obvious to achieve maximum efficiency at maximum displacement, there are some cases where maximum efficiency is achieved at a lower displacement. It was also found that for the given work cycle, a hydrostatic transmission with a variable displacement motor can be more efficient.

  12. The Principle of Maximum Conformality

    SciTech Connect

    Brodsky, Stanley J; Giustino, Di; /SLAC

    2011-04-05

    A key problem in making precise perturbative QCD predictions is the uncertainty in determining the renormalization scale of the running coupling {alpha}{sub s}({mu}{sup 2}). It is common practice to guess a physical scale {mu} = Q which is of order of a typical momentum transfer Q in the process, and then vary the scale over a range Q/2 and 2Q. This procedure is clearly problematic since the resulting fixed-order pQCD prediction will depend on the renormalization scheme, and it can even predict negative QCD cross sections at next-to-leading-order. Other heuristic methods to set the renormalization scale, such as the 'principle of minimal sensitivity', give unphysical results for jet physics, sum physics into the running coupling not associated with renormalization, and violate the transitivity property of the renormalization group. Such scale-setting methods also give incorrect results when applied to Abelian QED. Note that the factorization scale in QCD is introduced to match nonperturbative and perturbative aspects of the parton distributions in hadrons; it is present even in conformal theory and thus is a completely separate issue from renormalization scale setting. The PMC provides a consistent method for determining the renormalization scale in pQCD. The PMC scale-fixed prediction is independent of the choice of renormalization scheme, a key requirement of renormalization group invariance. The results avoid renormalon resummation and agree with QED scale-setting in the Abelian limit. The PMC global scale can be derived efficiently at NLO from basic properties of the PQCD cross section. The elimination of the renormalization scheme ambiguity using the PMC will not only increases the precision of QCD tests, but it will also increase the sensitivity of colliders to new physics beyond the Standard Model.

  13. Linearithmic time sparse and convex maximum margin clustering.

    PubMed

    Zhang, Xiao-Lei; Wu, Ji

    2012-12-01

    Recently, a new clustering method called maximum margin clustering (MMC) was proposed and has shown promising performances. It was originally formulated as a difficult nonconvex integer problem. To make the MMC problem practical, the researchers either relaxed the original MMC problem to inefficient convex optimization problems or reformulated it to nonconvex optimization problems, which sacrifice the convexity for efficiency. However, no approaches can both hold the convexity and be efficient. In this paper, a new linearithmic time sparse and convex MMC algorithm, called support-vector-regression-based MMC (SVR-MMC), is proposed. Generally, it first uses the SVR as the core of the MMC. Then, it is relaxed as a convex optimization problem, which is iteratively solved by the cutting-plane algorithm. Each cutting-plane subproblem is further decomposed to a serial supervised SVR problem by a new global extended-level method (GELM). Finally, each supervised SVR problem is solved in a linear time complexity by a new sparse-kernel SVR (SKSVR) algorithm. We further extend the SVR-MMC algorithm to the multiple-kernel clustering (MKC) problem and the multiclass MMC (M3C) problem, which are denoted as SVR-MKC and SVR-M3C, respectively. One key point of the algorithms is the utilization of the SVR. It can prevent the MMC and its extensions meeting an integer matrix programming problem. Another key point is the new SKSVR. It provides a linear time interface to the nonlinear kernel scenarios, so that the SVR-MMC and its extensions can keep a linearthmic time complexity in nonlinear kernel scenarios. Our experimental results on various real-world data sets demonstrate the effectiveness and the efficiency of the SVR-MMC and its two extensions. Moreover, the unsupervised application of the SVR-MKC to the voice activity detection (VAD) shows that the SVR-MKC can achieve good performances that are close to its supervised counterpart, meet the real-time demand of the VAD, and need no

  14. [Update of planning tables of cholesterol-lowering therapy orientated to achieve LDL therapeutic targets].

    PubMed

    Masana, Luis; Plana, Núria

    2015-01-01

    This is the third update of a planning-table for use in cholesterol-lowering therapy, so as to obtain LDLc objectives. This is an easy to use laptop tool to help choose the best statin or combination therapy (statin plus ezetimibe) depending on the current LDL concentration of the patient, and the LDLc objective to achieve. It is based on a colour code that indicates the drugs that are efficient enough to help patients to achieve their LDL goal. Along with the table, recommendations are given for the best strategy in order to implement the optimal therapy in a maximum of two clinical encounters. PMID:25865752

  15. [Update of planning tables of cholesterol-lowering therapy orientated to achieve LDL therapeutic targets].

    PubMed

    Masana, Luis; Plana, Núria

    2015-01-01

    This is the third update of a planning-table for use in cholesterol-lowering therapy, so as to obtain LDLc objectives. This is an easy to use laptop tool to help choose the best statin or combination therapy (statin plus ezetimibe) depending on the current LDL concentration of the patient, and the LDLc objective to achieve. It is based on a colour code that indicates the drugs that are efficient enough to help patients to achieve their LDL goal. Along with the table, recommendations are given for the best strategy in order to implement the optimal therapy in a maximum of two clinical encounters.

  16. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Maximum amount. 1261.102 Section 1261.102...) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30, 1988, the maximum amount that may be paid under the Military Personnel and Civilian Employees' Claim Act...

  17. 14 CFR 1261.102 - Maximum amount.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Maximum amount. 1261.102 Section 1261.102...) Employees' Personal Property Claims § 1261.102 Maximum amount. From October 1, 1982, to October 30, 1988, the maximum amount that may be paid under the Military Personnel and Civilian Employees' Claim Act...

  18. 49 CFR 107.329 - Maximum penalties.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... maximum civil penalty is $110,000 if the violation results in death, serious illness or severe injury to... 49 Transportation 2 2010-10-01 2010-10-01 false Maximum penalties. 107.329 Section 107.329... PROGRAM PROCEDURES Enforcement Compliance Orders and Civil Penalties § 107.329 Maximum penalties. (a)...

  19. 49 CFR 107.329 - Maximum penalties.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... maximum civil penalty is $110,000 if the violation results in death, serious illness or severe injury to... 49 Transportation 2 2011-10-01 2011-10-01 false Maximum penalties. 107.329 Section 107.329... PROGRAM PROCEDURES Enforcement Compliance Orders and Civil Penalties § 107.329 Maximum penalties. (a)...

  20. 20 CFR 228.14 - Family maximum.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... person's earnings record is limited. This limited amount is called the family maximum. The family maximum... the persons entitled to benefits on the insured individual's compensation would, except for the.... The maximum is computed as follows: (i) 150 percent of the first $230 of the individual's...

  1. 49 CFR 107.329 - Maximum penalties.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... maximum civil penalty is $110,000 if the violation results in death, serious illness or severe injury to... 49 Transportation 2 2012-10-01 2012-10-01 false Maximum penalties. 107.329 Section 107.329... PROGRAM PROCEDURES Enforcement Compliance Orders and Civil Penalties § 107.329 Maximum penalties. (a)...

  2. Efficient, resonantly pumped, room-temperature Er3+:GdVO4 laser.

    PubMed

    Ter-Gabrielyan, N; Fromzel, V; Ryba-Romanowski, W; Lukasiewicz, T; Dubinskii, M

    2012-04-01

    We report an efficient room-temperature operation of a resonantly pumped Er3+:GdVO4 laser at 1598.5 nm. The maximum continuous wave (CW) output power of 3.5 W with slope efficiency of 56% was achieved with resonant pumping by an Er-fiber laser at 1538.6 nm. With pumping by a commercial laser diode bar stack, a quasi-CW (QCW) output of 7.7 W and maximum slope efficiency of ~53% versus absorbed pump power were obtained. This is believed to be the first resonantly (in-band) pumped, room-temperature Er3+:GdVO4 laser.

  3. CORA: Emission Line Fitting with Maximum Likelihood

    NASA Astrophysics Data System (ADS)

    Ness, Jan-Uwe; Wichmann, Rainer

    2011-12-01

    The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.

  4. CORA - emission line fitting with Maximum Likelihood

    NASA Astrophysics Data System (ADS)

    Ness, J.-U.; Wichmann, R.

    2002-07-01

    The advent of pipeline-processed data both from space- and ground-based observatories often disposes of the need of full-fledged data reduction software with its associated steep learning curve. In many cases, a simple tool doing just one task, and doing it right, is all one wishes. In this spirit we introduce CORA, a line fitting tool based on the maximum likelihood technique, which has been developed for the analysis of emission line spectra with low count numbers and has successfully been used in several publications. CORA uses a rigorous application of Poisson statistics. From the assumption of Poissonian noise we derive the probability for a model of the emission line spectrum to represent the measured spectrum. The likelihood function is used as a criterion for optimizing the parameters of the theoretical spectrum and a fixed point equation is derived allowing an efficient way to obtain line fluxes. As an example we demonstrate the functionality of the program with an X-ray spectrum of Capella obtained with the Low Energy Transmission Grating Spectrometer (LETGS) on board the Chandra observatory and choose the analysis of the Ne IX triplet around 13.5 Å.

  5. Maximum Data Collection Rate Routing Protocol Based on Topology Control for Rechargeable Wireless Sensor Networks.

    PubMed

    Lin, Haifeng; Bai, Di; Gao, Demin; Liu, Yunfei

    2016-07-30

    In Rechargeable Wireless Sensor Networks (R-WSNs), in order to achieve the maximum data collection rate it is critical that sensors operate in very low duty cycles because of the sporadic availability of energy. A sensor has to stay in a dormant state in most of the time in order to recharge the battery and use the energy prudently. In addition, a sensor cannot always conserve energy if a network is able to harvest excessive energy from the environment due to its limited storage capacity. Therefore, energy exploitation and energy saving have to be traded off depending on distinct application scenarios. Since higher data collection rate or maximum data collection rate is the ultimate objective for sensor deployment, surplus energy of a node can be utilized for strengthening packet delivery efficiency and improving the data generating rate in R-WSNs. In this work, we propose an algorithm based on data aggregation to compute an upper data generation rate by maximizing it as an optimization problem for a network, which is formulated as a linear programming problem. Subsequently, a dual problem by introducing Lagrange multipliers is constructed, and subgradient algorithms are used to solve it in a distributed manner. At the same time, a topology controlling scheme is adopted for improving the network's performance. Through extensive simulation and experiments, we demonstrate that our algorithm is efficient at maximizing the data collection rate in rechargeable wireless sensor networks.

  6. Maximum Data Collection Rate Routing Protocol Based on Topology Control for Rechargeable Wireless Sensor Networks.

    PubMed

    Lin, Haifeng; Bai, Di; Gao, Demin; Liu, Yunfei

    2016-01-01

    In Rechargeable Wireless Sensor Networks (R-WSNs), in order to achieve the maximum data collection rate it is critical that sensors operate in very low duty cycles because of the sporadic availability of energy. A sensor has to stay in a dormant state in most of the time in order to recharge the battery and use the energy prudently. In addition, a sensor cannot always conserve energy if a network is able to harvest excessive energy from the environment due to its limited storage capacity. Therefore, energy exploitation and energy saving have to be traded off depending on distinct application scenarios. Since higher data collection rate or maximum data collection rate is the ultimate objective for sensor deployment, surplus energy of a node can be utilized for strengthening packet delivery efficiency and improving the data generating rate in R-WSNs. In this work, we propose an algorithm based on data aggregation to compute an upper data generation rate by maximizing it as an optimization problem for a network, which is formulated as a linear programming problem. Subsequently, a dual problem by introducing Lagrange multipliers is constructed, and subgradient algorithms are used to solve it in a distributed manner. At the same time, a topology controlling scheme is adopted for improving the network's performance. Through extensive simulation and experiments, we demonstrate that our algorithm is efficient at maximizing the data collection rate in rechargeable wireless sensor networks. PMID:27483282

  7. Maximum Data Collection Rate Routing Protocol Based on Topology Control for Rechargeable Wireless Sensor Networks

    PubMed Central

    Lin, Haifeng; Bai, Di; Gao, Demin; Liu, Yunfei

    2016-01-01

    In Rechargeable Wireless Sensor Networks (R-WSNs), in order to achieve the maximum data collection rate it is critical that sensors operate in very low duty cycles because of the sporadic availability of energy. A sensor has to stay in a dormant state in most of the time in order to recharge the battery and use the energy prudently. In addition, a sensor cannot always conserve energy if a network is able to harvest excessive energy from the environment due to its limited storage capacity. Therefore, energy exploitation and energy saving have to be traded off depending on distinct application scenarios. Since higher data collection rate or maximum data collection rate is the ultimate objective for sensor deployment, surplus energy of a node can be utilized for strengthening packet delivery efficiency and improving the data generating rate in R-WSNs. In this work, we propose an algorithm based on data aggregation to compute an upper data generation rate by maximizing it as an optimization problem for a network, which is formulated as a linear programming problem. Subsequently, a dual problem by introducing Lagrange multipliers is constructed, and subgradient algorithms are used to solve it in a distributed manner. At the same time, a topology controlling scheme is adopted for improving the network’s performance. Through extensive simulation and experiments, we demonstrate that our algorithm is efficient at maximizing the data collection rate in rechargeable wireless sensor networks. PMID:27483282

  8. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS...) of the Act. (4) If the Administrator has either proposed a relevant emission standard pursuant to... the MACT emission limitation or standard as determined according to the principles set forth...

  9. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS...) of the Act. (4) If the Administrator has either proposed a relevant emission standard pursuant to... the MACT emission limitation or standard as determined according to the principles set forth...

  10. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS...) of the Act. (4) If the Administrator has either proposed a relevant emission standard pursuant to... the MACT emission limitation or standard as determined according to the principles set forth...

  11. 40 CFR 63.43 - Maximum achievable control technology (MACT) determinations for constructed and reconstructed...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS...) of the Act. (4) If the Administrator has either proposed a relevant emission standard pursuant to... the MACT emission limitation or standard as determined according to the principles set forth...

  12. Comparing Science Achievement Constructs: Targeted and Achieved

    ERIC Educational Resources Information Center

    Ferrara, Steve; Duncan, Teresa

    2011-01-01

    This article illustrates how test specifications based solely on academic content standards, without attention to other cognitive skills and item response demands, can fall short of their targeted constructs. First, the authors inductively describe the science achievement construct represented by a statewide sixth-grade science proficiency test.…

  13. Mobility and Reading Achievement.

    ERIC Educational Resources Information Center

    Waters, Theresa Z.

    A study examined the effect of geographic mobility on elementary school students' achievement. Although such mobility, which requires students to make multiple moves among schools, can have a negative impact on academic achievement, the hypothesis for the study was that it was not a determining factor in reading achievement test scores. Subjects…

  14. Adapting livestock behaviour to achieve management goals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using livestock to efficiently achieve management goals requires melding animal behavior with mechanical and electronic equipment. Practices such as autonomously obtaining individual animal liveweight when combined with individual animal electronic identification can produce numerous cost saving ad...

  15. 50 CFR 259.34 - Minimum and maximum deposits; maximum time to deposit.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Minimum and maximum deposits; maximum time... Capital Construction Fund Agreement § 259.34 Minimum and maximum deposits; maximum time to deposit. (a... than prescribed herein: Provided, The party demonstrates to the Secretary's satisfaction...

  16. Computationally efficient control allocation

    NASA Technical Reports Server (NTRS)

    Durham, Wayne (Inventor)

    2001-01-01

    A computationally efficient method for calculating near-optimal solutions to the three-objective, linear control allocation problem is disclosed. The control allocation problem is that of distributing the effort of redundant control effectors to achieve some desired set of objectives. The problem is deemed linear if control effectiveness is affine with respect to the individual control effectors. The optimal solution is that which exploits the collective maximum capability of the effectors within their individual physical limits. Computational efficiency is measured by the number of floating-point operations required for solution. The method presented returned optimal solutions in more than 90% of the cases examined; non-optimal solutions returned by the method were typically much less than 1% different from optimal and the errors tended to become smaller than 0.01% as the number of controls was increased. The magnitude of the errors returned by the present method was much smaller than those that resulted from either pseudo inverse or cascaded generalized inverse solutions. The computational complexity of the method presented varied linearly with increasing numbers of controls; the number of required floating point operations increased from 5.5 i, to seven times faster than did the minimum-norm solution (the pseudoinverse), and at about the same rate as did the cascaded generalized inverse solution. The computational requirements of the method presented were much better than that of previously described facet-searching methods which increase in proportion to the square of the number of controls.

  17. Skewness for Maximum Likelihood Estimators of the Negative Binomial Distribution

    SciTech Connect

    Bowman, Kimiko o

    2007-01-01

    The probability generating function of one version of the negative binomial distribution being (p + 1 - pt){sup -k}, we study elements of the Hessian and in particular Fisher's discovery of a series form for the variance of k, the maximum likelihood estimator, and also for the determinant of the Hessian. There is a link with the Psi function and its derivatives. Basic algebra is excessively complicated and a Maple code implementation is an important task in the solution process. Low order maximum likelihood moments are given and also Fisher's examples relating to data associated with ticks on sheep. Efficiency of moment estimators is mentioned, including the concept of joint efficiency. In an Addendum we give an interesting formula for the difference of two Psi functions.

  18. Fiber-coupled nanowire photon counter at 1550 nm with 24% system detection efficiency.

    PubMed

    Hu, Xiaolong; Zhong, Tian; White, James E; Dauler, Eric A; Najafi, Faraz; Herder, Charles H; Wong, Franco N C; Berggren, Karl K

    2009-12-01

    We developed a fiber-coupled superconducting nanowire single-photon detector system in a close-cycled cryocooler and achieved 24% and 22% system detection efficiencies at wavelengths of 1550 and 1315 nm, respectively. The maximum dark count rate was approximately 1000 counts/s.

  19. Interplanetary monitoring platform engineering history and achievements

    NASA Technical Reports Server (NTRS)

    Butler, P. M.

    1980-01-01

    In the fall of 1979, last of ten Interplanetary Monitoring Platform Satellite (IMP) missions ended a ten year series of flights dedicated to obtaining new knowledge of the radiation effects in outer space and of solar phenomena during a period of maximum solar flare activity. The technological achievements and scientific accomplishments from the IMP program are described.

  20. 5 CFR 1600.22 - Maximum contributions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Maximum contributions. 1600.22 Section 1600.22 Administrative Personnel FEDERAL RETIREMENT THRIFT INVESTMENT BOARD EMPLOYEE CONTRIBUTION ELECTIONS AND CONTRIBUTION ALLOCATIONS Program of Contributions § 1600.22 Maximum contributions. (a)...

  1. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  2. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  3. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  4. Maximum entropy image reconstruction from projections

    NASA Astrophysics Data System (ADS)

    Bara, N.; Murata, K.

    1981-07-01

    The maximum entropy method is applied to image reconstruction from projections, of which angular view is restricted. The relaxation parameters are introduced to the maximum entropy reconstruction and after iteration the median filtering is implemented. These procedures improve the quality of the reconstructed image from noisy projections

  5. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... total wages (see 20 CFR 404.203(m)) for the second year before the individual dies or becomes eligible... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Family maximum. 229.48 Section 229.48... OVERALL MINIMUM GUARANTEE Computation of the Overall Minimum Rate § 229.48 Family maximum. (a)...

  6. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 12 2013-01-01 2013-01-01 false Maximum grants. 1778.11 Section 1778.11 Agriculture... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not... the filing of an application. (b) Grants made for repairs, partial replacement, or...

  7. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Maximum grants. 1778.11 Section 1778.11 Agriculture... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not... the filing of an application. (b) Grants made for repairs, partial replacement, or...

  8. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Maximum grant. 130.440 Section 130... § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the minimum statutory amount, or its pro rata share of all SBDC grants as determined by the statutory formula set...

  9. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Maximum grant. 130.440 Section 130... § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the minimum statutory amount, or its pro rata share of all SBDC grants as determined by the statutory formula set...

  10. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Maximum grant. 130.440 Section 130... § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the minimum statutory amount, or its pro rata share of all SBDC grants as determined by the statutory formula set...

  11. 20 CFR 229.48 - Family maximum.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... month on one person's earnings record is limited. This limited amount is called the family maximum. The family maximum used to adjust the social security overall minimum rate is based on the employee's Overall..., when any of the persons entitled to benefits on the insured individual's compensation would, except...

  12. 13 CFR 130.440 - Maximum grant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Maximum grant. 130.440 Section 130.440 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS DEVELOPMENT CENTERS § 130.440 Maximum grant. No recipient shall receive an SBDC grant exceeding the greater of the...

  13. 49 CFR 107.329 - Maximum penalties.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... violation, except the maximum civil penalty is $175,000 if the violation results in death, serious illness... civil penalty is $175,000 if the violation results in death, serious illness or severe injury to any... 49 Transportation 2 2013-10-01 2013-10-01 false Maximum penalties. 107.329 Section...

  14. 49 CFR 107.329 - Maximum penalties.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... violation, except the maximum civil penalty is $175,000 if the violation results in death, serious illness... civil penalty is $175,000 if the violation results in death, serious illness or severe injury to any... 49 Transportation 2 2014-10-01 2014-10-01 false Maximum penalties. 107.329 Section...

  15. Let's Design for Efficiency.

    ERIC Educational Resources Information Center

    Campbell, Edward A.

    1966-01-01

    Laboratory facilities should be designed with the most effective arrangement for maximum instructional efficiency and safety. Periodic evaluation and analysis should be used for improving instruction, abating safety hazards, and presenting an efficient learning environment. Attention should be focused on--(1) instructional program, (2) students,…

  16. General Achievement Trends: Oklahoma

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  17. General Achievement Trends: Georgia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  18. General Achievement Trends: Nebraska

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  19. General Achievement Trends: Arkansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  20. General Achievement Trends: Maryland

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  1. General Achievement Trends: Maine

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  2. General Achievement Trends: Iowa

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  3. General Achievement Trends: Texas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  4. General Achievement Trends: Hawaii

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  5. General Achievement Trends: Kansas

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  6. General Achievement Trends: Florida

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  7. General Achievement Trends: Massachusetts

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  8. General Achievement Trends: Tennessee

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  9. General Achievement Trends: Alabama

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  10. General Achievement Trends: Virginia

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  11. General Achievement Trends: Michigan

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  12. General Achievement Trends: Colorado

    ERIC Educational Resources Information Center

    Center on Education Policy, 2009

    2009-01-01

    This general achievement trends profile includes information that the Center on Education Policy (CEP) and the Human Resources Research Organization (HumRRO) obtained from states from fall 2008 through April 2009. Included herein are: (1) Bullet points summarizing key findings about achievement trends in that state at three performance…

  13. Inverting the Achievement Pyramid

    ERIC Educational Resources Information Center

    White-Hood, Marian; Shindel, Melissa

    2006-01-01

    Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

  14. Achievement Test Program.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus. Trade and Industrial Education Service.

    The Ohio Trade and Industrial Education Achievement Test battery is comprised of seven basic achievement tests: Machine Trades, Automotive Mechanics, Basic Electricity, Basic Electronics, Mechanical Drafting, Printing, and Sheet Metal. The tests were developed by subject matter committees and specialists in testing and research. The Ohio Trade and…

  15. School Effects on Achievement.

    ERIC Educational Resources Information Center

    Nichols, Robert C.

    The New York State Education Department conducts a Pupil Evaluation Program (PEP) in which each year all third, sixth, and ninth grade students in the state are given a series of achievement tests in reading and mathematics. The data accumulated by the department includes achievement test scores, teacher characteristics, building and curriculum…

  16. Heritability of Creative Achievement

    ERIC Educational Resources Information Center

    Piffer, Davide; Hur, Yoon-Mi

    2014-01-01

    Although creative achievement is a subject of much attention to lay people, the origin of individual differences in creative accomplishments remain poorly understood. This study examined genetic and environmental influences on creative achievement in an adult sample of 338 twins (mean age = 26.3 years; SD = 6.6 years). Twins completed the Creative…

  17. Confronting the Achievement Gap

    ERIC Educational Resources Information Center

    Gardner, David

    2007-01-01

    This article talks about the large achievement gap between children of color and their white peers. The reasons for the achievement gap are varied. First, many urban minorities come from a background of poverty. One of the detrimental effects of growing up in poverty is receiving inadequate nourishment at a time when bodies and brains are rapidly…

  18. Achieving Public Schools

    ERIC Educational Resources Information Center

    Abowitz, Kathleen Knight

    2011-01-01

    Public schools are functionally provided through structural arrangements such as government funding, but public schools are achieved in substance, in part, through local governance. In this essay, Kathleen Knight Abowitz explains the bifocal nature of achieving public schools; that is, that schools are both subject to the unitary Public compact of…

  19. States that give the maximum signal-to-quantum noise ratio for a fixed energy

    NASA Technical Reports Server (NTRS)

    Yuen, H. P.

    1976-01-01

    Under a radiation power constraint, the maximum signal-to-quantum noise ratio obtainable for any state of a radiation field is found. This maximum value is achieved by the two-photon coherent states introduced previously to describe two-photon lasers.

  20. Thermally Activated Delayed Fluorescence Polymers for Efficient Solution-Processed Organic Light-Emitting Diodes.

    PubMed

    Lee, Sae Youn; Yasuda, Takuma; Komiyama, Hideaki; Lee, Jiyoung; Adachi, Chihaya

    2016-06-01

    Thermally activated delayed fluorescence (TADF) π-conjugated polymers are developed for solution-processed TADF-OLEDs. Benzophenone-based alternating donor-acceptor structures contribute to the small ∆EST , enabling efficient exciton-harvesting through TADF. Solution-processed OLEDs using the TADF polymers as emitters can achieve high maximum external electroluminescence efficiencies of up to 9.3%. PMID:27001891

  1. Development of 100-W High-Efficiency MPPT Power Conditioner and Evaluation of TEG System with Battery Load

    NASA Astrophysics Data System (ADS)

    Nagayoshi, Hiroshi; Nakabayashi, Tatsuya; Maiwa, Hiroshi; Kajikawa, Takenobu

    2011-05-01

    This paper describes a practical high-efficiency thermoelectric (TE) power conditioner with maximum power point tracking (MPPT) control for thermoelectric generators and the operation results for a battery load system. This power conditioner comprises a high-frequency step-up/step-down switching converter and a microcontroller; a synchronized switching circuit is introduced to achieve high conversion efficiency. Furthermore, it is equipped with a battery charge control program and has a maximum conversion efficiency of 96.7%. An impedance matching method developed for MPPT control showed excellent response against a change in the TEG output, making it suitable for solar TEGs as well as general applications.

  2. Energy efficiency of adiabatic superconductor logic

    NASA Astrophysics Data System (ADS)

    Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki

    2015-01-01

    Adiabatic superconductor logic (ASL), including adiabatic quantum-flux-parametron (AQFP) logic, exhibits high energy efficiency because its bit energy can be decreased below the thermal energy through adiabatic switching operations. In the present paper, we present the general scaling laws of ASL and compare the energy efficiency of ASL with those of other energy-efficient logics. Also, we discuss the minimum energy-delay product (EDP) of ASL at finite temperature. Our study shows that there is a maximum temperature at which the EDP can reach the quantum limit given by ħ/2, which is dependent on the superconductor material and the Josephson junction quality, and that it is reasonable to operate ASL at cryogenic temperatures in order to achieve an EDP that approaches ħ/2.

  3. Student Achievement Factors

    ERIC Educational Resources Information Center

    Bertolini, Katherine; Stremmel, Andrew; Thorngren, Jill

    2012-01-01

    Effective practices for education are essential to insure public investment in our schools provides the maximum yield for our students, communities, states, and nation. The challenge has been defining and measuring terms such as effective, proficient, and sufficient when we examine instructional practice, student outcomes and funding equity. This…

  4. 14 CFR 65.47 - Maximum hours.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Air Traffic Control Tower Operators § 65.47 Maximum hours. Except in an emergency, a certificated air traffic control tower operator must be relieved of all...

  5. 14 CFR 65.47 - Maximum hours.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Air Traffic Control Tower Operators § 65.47 Maximum hours. Except in an emergency, a certificated air traffic control tower operator must be relieved of all...

  6. 14 CFR 65.47 - Maximum hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CERTIFICATION: AIRMEN OTHER THAN FLIGHT CREWMEMBERS Air Traffic Control Tower Operators § 65.47 Maximum hours. Except in an emergency, a certificated air traffic control tower operator must be relieved of all...

  7. Maximum-Likelihood Detection Of Noncoherent CPM

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Simon, Marvin K.

    1993-01-01

    Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.

  8. Maximum forces and deflections from orthodontic appliances.

    PubMed

    Burstone, C J; Goldberg, A J

    1983-08-01

    The maximum bending moment of an orthodontic wire is an important parameter in the design and use of an orthodontic appliance. It is the wire property that determines how much force an appliance can deliver. A bending test which allows direct measurement of the maximum bending moment was developed. Data produced from this test are independent of wire length and configuration. The maximum bending moment, percent recovery, and maximum springback were determined for round and rectangular cross sections of stainless steel, nickel-titanium, and beta-titanium wires. The data suggest the need for more specifically defining maximum moment and maximum springback. Three maximum bending moments are described: Me, My, and Mult. My and Mult are clinically the most significant. Appliances that are required to have no permanent deformation must operate below My. Appliances that exhibit marked permanent deformation may be used in some applications and, if so, higher bending moments can be produced. In order of magnitude, the maximum bending moment at yield is largest in stainless steel, beta-titanium, and nickel-titanium for a given cross section. Nickel-titanium and beta-titanium have significantly larger springback than stainless steel determined at the moment at yield. Nickel-titanium did not follow the theoretical ratio between ultimate bending moment and the bending moment at yield, exhibiting a very large ratio. The study supports the hypothesis that most orthodontic appliances are activated in a range where both plastic and elastic behavior occurs; therefore, the use of yield strengths for calculation of force magnitude can lead to a significant error in predicting the forces delivered. PMID:6576645

  9. Limitations to maximum running speed on flat curves.

    PubMed

    Chang, Young-Hui; Kram, Rodger

    2007-03-01

    Why is maximal running speed reduced on curved paths? The leading explanation proposes that an increase in lateral ground reaction force necessitates a decrease in peak vertical ground reaction force, assuming that maximum leg extension force is the limiting factor. Yet, no studies have directly measured these forces or tested this critical assumption. We measured maximum sprint velocities and ground reaction forces for five male humans sprinting along a straight track and compared them to sprints along circular tracks of 1, 2, 3, 4 and 6 m radii. Circular track sprint trials were performed either with or without a tether that applied centripetal force to the center of mass. Sprinters generated significantly smaller peak resultant ground reaction forces during normal curve sprinting compared to straight sprinting. This provides direct evidence against the idea that maximum leg extension force is always achieved and is the limiting factor. Use of the tether increased sprint speed, but not to expected values. During curve sprinting, the inside leg consistently generated smaller peak forces compared to the outside leg. Several competing biomechanical constraints placed on the stance leg during curve sprinting likely make the inside leg particularly ineffective at generating the ground reaction forces necessary to attain maximum velocities comparable to straight path sprinting. The ability of quadrupeds to redistribute function across multiple stance legs and decouple these multiple constraints may provide a distinct advantage for turning performance. PMID:17337710

  10. Limitations to maximum running speed on flat curves.

    PubMed

    Chang, Young-Hui; Kram, Rodger

    2007-03-01

    Why is maximal running speed reduced on curved paths? The leading explanation proposes that an increase in lateral ground reaction force necessitates a decrease in peak vertical ground reaction force, assuming that maximum leg extension force is the limiting factor. Yet, no studies have directly measured these forces or tested this critical assumption. We measured maximum sprint velocities and ground reaction forces for five male humans sprinting along a straight track and compared them to sprints along circular tracks of 1, 2, 3, 4 and 6 m radii. Circular track sprint trials were performed either with or without a tether that applied centripetal force to the center of mass. Sprinters generated significantly smaller peak resultant ground reaction forces during normal curve sprinting compared to straight sprinting. This provides direct evidence against the idea that maximum leg extension force is always achieved and is the limiting factor. Use of the tether increased sprint speed, but not to expected values. During curve sprinting, the inside leg consistently generated smaller peak forces compared to the outside leg. Several competing biomechanical constraints placed on the stance leg during curve sprinting likely make the inside leg particularly ineffective at generating the ground reaction forces necessary to attain maximum velocities comparable to straight path sprinting. The ability of quadrupeds to redistribute function across multiple stance legs and decouple these multiple constraints may provide a distinct advantage for turning performance.

  11. Student Achievement and Motivation

    ERIC Educational Resources Information Center

    Flammer, Gordon H.; Mecham, Robert C.

    1974-01-01

    Compares the lecture and self-paced methods of instruction on the basis of student motivation and achieveme nt, comparing motivating and demotivating factors in each, and their potential for motivation and achievement. (Authors/JR)

  12. North Atlantic Deep Water Production during the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Howe, Jacob N. W.; Piotrowski, Alexander M.; Noble, Taryn L.; Mulitza, Stefan; Chiessi, Cristiano M.; Bayon, Germain

    2016-06-01

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial-interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters.

  13. North Atlantic Deep Water Production during the Last Glacial Maximum.

    PubMed

    Howe, Jacob N W; Piotrowski, Alexander M; Noble, Taryn L; Mulitza, Stefan; Chiessi, Cristiano M; Bayon, Germain

    2016-01-01

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial-interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ(13)C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters. PMID:27256826

  14. North Atlantic Deep Water Production during the Last Glacial Maximum

    PubMed Central

    Howe, Jacob N. W.; Piotrowski, Alexander M.; Noble, Taryn L.; Mulitza, Stefan; Chiessi, Cristiano M.; Bayon, Germain

    2016-01-01

    Changes in deep ocean ventilation are commonly invoked as the primary cause of lower glacial atmospheric CO2. The water mass structure of the glacial deep Atlantic Ocean and the mechanism by which it may have sequestered carbon remain elusive. Here we present neodymium isotope measurements from cores throughout the Atlantic that reveal glacial–interglacial changes in water mass distributions. These results demonstrate the sustained production of North Atlantic Deep Water under glacial conditions, indicating that southern-sourced waters were not as spatially extensive during the Last Glacial Maximum as previously believed. We demonstrate that the depleted glacial δ13C values in the deep Atlantic Ocean cannot be explained solely by water mass source changes. A greater amount of respired carbon, therefore, must have been stored in the abyssal Atlantic during the Last Glacial Maximum. We infer that this was achieved by a sluggish deep overturning cell, comprised of well-mixed northern- and southern-sourced waters. PMID:27256826

  15. Triadic conceptual structure of the maximum entropy approach to evolution.

    PubMed

    Herrmann-Pillath, Carsten; Salthe, Stanley N

    2011-03-01

    Many problems in evolutionary theory are cast in dyadic terms, such as the polar oppositions of organism and environment. We argue that a triadic conceptual structure offers an alternative perspective under which the information generating role of evolution as a physical process can be analyzed, and propose a new diagrammatic approach. Peirce's natural philosophy was deeply influenced by his reception of both Darwin's theory and thermodynamics. Thus, we elaborate on a new synthesis which puts together his theory of signs and modern Maximum Entropy approaches to evolution in a process discourse. Following recent contributions to the naturalization of Peircean semiosis, pointing towards 'physiosemiosis' or 'pansemiosis', we show that triadic structures involve the conjunction of three different kinds of causality, efficient, formal and final. In this, we accommodate the state-centered thermodynamic framework to a process approach. We apply this on Ulanowicz's analysis of autocatalytic cycles as primordial patterns of life. This paves the way for a semiotic view of thermodynamics which is built on the idea that Peircean interpretants are systems of physical inference devices evolving under natural selection. In this view, the principles of Maximum Entropy, Maximum Power, and Maximum Entropy Production work together to drive the emergence of information carrying structures, which at the same time maximize information capacity as well as the gradients of energy flows, such that ultimately, contrary to Schrödinger's seminal contribution, the evolutionary process is seen to be a physical expression of the Second Law. PMID:21055440

  16. Triadic conceptual structure of the maximum entropy approach to evolution.

    PubMed

    Herrmann-Pillath, Carsten; Salthe, Stanley N

    2011-03-01

    Many problems in evolutionary theory are cast in dyadic terms, such as the polar oppositions of organism and environment. We argue that a triadic conceptual structure offers an alternative perspective under which the information generating role of evolution as a physical process can be analyzed, and propose a new diagrammatic approach. Peirce's natural philosophy was deeply influenced by his reception of both Darwin's theory and thermodynamics. Thus, we elaborate on a new synthesis which puts together his theory of signs and modern Maximum Entropy approaches to evolution in a process discourse. Following recent contributions to the naturalization of Peircean semiosis, pointing towards 'physiosemiosis' or 'pansemiosis', we show that triadic structures involve the conjunction of three different kinds of causality, efficient, formal and final. In this, we accommodate the state-centered thermodynamic framework to a process approach. We apply this on Ulanowicz's analysis of autocatalytic cycles as primordial patterns of life. This paves the way for a semiotic view of thermodynamics which is built on the idea that Peircean interpretants are systems of physical inference devices evolving under natural selection. In this view, the principles of Maximum Entropy, Maximum Power, and Maximum Entropy Production work together to drive the emergence of information carrying structures, which at the same time maximize information capacity as well as the gradients of energy flows, such that ultimately, contrary to Schrödinger's seminal contribution, the evolutionary process is seen to be a physical expression of the Second Law.

  17. 44 CFR 321.4 - Achieving production readiness.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... achieve a capability for maximum production of “urgent” items during the initial phase of war, the... power, fuel, and water, or on long-distance communications; with spare replacements for...

  18. 44 CFR 321.4 - Achieving production readiness.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... achieve a capability for maximum production of “urgent” items during the initial phase of war, the... power, fuel, and water, or on long-distance communications; with spare replacements for...

  19. 44 CFR 321.4 - Achieving production readiness.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... achieve a capability for maximum production of “urgent” items during the initial phase of war, the... power, fuel, and water, or on long-distance communications; with spare replacements for...

  20. A Maximum-Entropy approach for accurate document annotation in the biomedical domain.

    PubMed

    Tsatsaronis, George; Macari, Natalia; Torge, Sunna; Dietze, Heiko; Schroeder, Michael

    2012-01-01

    The increasing number of scientific literature on the Web and the absence of efficient tools used for classifying and searching the documents are the two most important factors that influence the speed of the search and the quality of the results. Previous studies have shown that the usage of ontologies makes it possible to process document and query information at the semantic level, which greatly improves the search for the relevant information and makes one step further towards the Semantic Web. A fundamental step in these approaches is the annotation of documents with ontology concepts, which can also be seen as a classification task. In this paper we address this issue for the biomedical domain and present a new automated and robust method, based on a Maximum Entropy approach, for annotating biomedical literature documents with terms from the Medical Subject Headings (MeSH).The experimental evaluation shows that the suggested Maximum Entropy approach for annotating biomedical documents with MeSH terms is highly accurate, robust to the ambiguity of terms, and can provide very good performance even when a very small number of training documents is used. More precisely, we show that the proposed algorithm obtained an average F-measure of 92.4% (precision 99.41%, recall 86.77%) for the full range of the explored terms (4,078 MeSH terms), and that the algorithm's performance is resilient to terms' ambiguity, achieving an average F-measure of 92.42% (precision 99.32%, recall 86.87%) in the explored MeSH terms which were found to be ambiguous according to the Unified Medical Language System (UMLS) thesaurus. Finally, we compared the results of the suggested methodology with a Naive Bayes and a Decision Trees classification approach, and we show that the Maximum Entropy based approach performed with higher F-Measure in both ambiguous and monosemous MeSH terms.

  1. Maximum permissible voltage of YBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.

    2014-06-01

    Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  2. Cell Development obeys Maximum Fisher Information

    PubMed Central

    Frieden, B. Roy; Gatenby, Robert A.

    2014-01-01

    Eukaryotic cell development has been optimized by natural selection to obey maximal intracellular flux of messenger proteins. This, in turn, implies maximum Fisher information on angular position about a target nuclear pore complex (NPR). The cell is simply modeled as spherical, with cell membrane (CM) diameter 10μm and concentric nuclear membrane (NM) diameter 6μm. The NM contains ≈ 3000 nuclear pore complexes (NPCs). Development requires messenger ligands to travel from the CM-NPC-DNA target binding sites. Ligands acquire negative charge by phosphorylation, passing through the cytoplasm over Newtonian trajectories toward positively charged NPCs (utilizing positive nuclear localization sequences). The CM-NPC channel obeys maximized mean protein flux F and Fisher information I at the NPC, with first-order δI = 0 and approximate 2nd-order δ2I ≈ 0 stability to environmental perturbations. Many of its predictions are confirmed, including the dominance of protein pathways of from 1–4 proteins, a 4nm size for the EGFR protein and the flux value F ≈1016 proteins/m2-s. After entering the nucleus, each protein ultimately delivers its ligand information to a DNA target site with maximum probability, i.e. maximum Kullback-Liebler entropy HKL. In a smoothness limit HKL → IDNA/2, so that the total CM-NPC-DNA channel obeys maximum Fisher I. Thus maximum information → non-equilibrium, one condition for life. PMID:23747917

  3. Maximum magnitude earthquakes induced by fluid injection

    NASA Astrophysics Data System (ADS)

    McGarr, A.

    2014-02-01

    Analysis of numerous case histories of earthquake sequences induced by fluid injection at depth reveals that the maximum magnitude appears to be limited according to the total volume of fluid injected. Similarly, the maximum seismic moment seems to have an upper bound proportional to the total volume of injected fluid. Activities involving fluid injection include (1) hydraulic fracturing of shale formations or coal seams to extract gas and oil, (2) disposal of wastewater from these gas and oil activities by injection into deep aquifers, and (3) the development of enhanced geothermal systems by injecting water into hot, low-permeability rock. Of these three operations, wastewater disposal is observed to be associated with the largest earthquakes, with maximum magnitudes sometimes exceeding 5. To estimate the maximum earthquake that could be induced by a given fluid injection project, the rock mass is assumed to be fully saturated, brittle, to respond to injection with a sequence of earthquakes localized to the region weakened by the pore pressure increase of the injection operation and to have a Gutenberg-Richter magnitude distribution with a b value of 1. If these assumptions correctly describe the circumstances of the largest earthquake, then the maximum seismic moment is limited to the volume of injected liquid times the modulus of rigidity. Observations from the available case histories of earthquakes induced by fluid injection are consistent with this bound on seismic moment. In view of the uncertainties in this analysis, however, this should not be regarded as an absolute physical limit.

  4. Mapping the MPM maximum flow algorithm on GPUs

    NASA Astrophysics Data System (ADS)

    Solomon, Steven; Thulasiraman, Parimala

    2010-11-01

    The GPU offers a high degree of parallelism and computational power that developers can exploit for general purpose parallel applications. As a result, a significant level of interest has been directed towards GPUs in recent years. Regular applications, however, have traditionally been the focus of work on the GPU. Only very recently has there been a growing number of works exploring the potential of irregular applications on the GPU. We present a work that investigates the feasibility of Malhotra, Pramodh Kumar and Maheshwari's "MPM" maximum flow algorithm on the GPU that achieves an average speedup of 8 when compared to a sequential CPU implementation.

  5. Efficiency of continuous-wave solar pumped semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Johnson, Stanley; Küppers, Franko; Pau, Stanley

    2013-04-01

    We report the results of an efficient solar pumped semiconductor laser system that uses high efficiency multi-junction photovoltaic cells and laser diodes in order to achieve the sunlight to laser light conversion efficiency of over 10% without any active cooling and concentration optics. Semiconductor lasers with wavelength from 445 nm to 1550 nm are powered directly by an array of photovoltaic (PV) cells under one sun illumination (100 mW/cm2). The maximum energy efficiency reaches 10.34% at 976 nm with an output power of 4.31 W. This system is inherently more efficient than direct solar pumped lasers that have been studied in the past and could play a key role in future renewable energy production and power beaming applications.

  6. Maximum-power quantum-mechanical Carnot engine.

    PubMed

    Abe, Sumiyoshi

    2011-04-01

    In their work [J. Phys. A 33, 4427 (2000)], Bender, Brody, and Meister have shown by employing a two-state model of a particle confined in the one-dimensional infinite potential well that it is possible to construct a quantum-mechanical analog of the Carnot engine through changes of both the width of the well and the quantum state in a specific manner. Here, a discussion is developed about realizing the maximum power of such an engine, where the width of the well moves at low but finite speed. The efficiency of the engine at the maximum power output is found to be universal independently of any of the parameters contained in the model.

  7. The Maximum Mass of Rotating Strange Stars

    NASA Astrophysics Data System (ADS)

    Szkudlarek, M.; Gondek-Rosiń; ska, D.; Villain, L.; Ansorg, M.

    2012-12-01

    Strange quark stars are considered as a possible alternative to neutron stars as compact objects (e.g. Weber 2003). A hot compact star (a proto-neutron star or a strange star) born in a supernova explosion or a remnant of neutron stars binary merger are expected to rotate differentially and be important sources of gravitational waves. We present results of the first relativistic calculations of differentially rotating strange quark stars for broad ranges of degree of differential rotation and maximum densities. Using a highly accurate, relativistic code we show that rotation may cause a significant increase of maximum allowed mass of strange stars, much larger than in the case of neutron stars with the same degree of differential rotation. Depending on the maximum allowed mass a massive neutron star (strange star) can be temporarily stabilized by differential rotation or collapse to a black hole.

  8. Surface tension maximum of liquid 3He

    NASA Astrophysics Data System (ADS)

    Matsumoto, Koichi; Hasegawa, Syuichi; Suzuki, Masaru; Okuda, Yuichi

    2000-07-01

    The surface tension of liquid 3He was measured using the capillary-rise method. Suzuki et al. have reported that its temperature dependence was almost quenched below 120 mK. Here we have examined it with higher precision and found that it has a small maximum around 100 mK. The amount of the maximum is about 3×10 -4 as a fraction of the surface tension at 0 K. The density of liquid 3He increases with temperature by about 5×10 -4 in Δ ρ/ ρ between 0 and 100 mK. This density change could be one of the reasons of the surface tension maximum around 100 mK.

  9. Maximum mixing times of methane and air under non-reacting and reacting conditions

    SciTech Connect

    Brasoveanu, D.; Gupta, A.K.

    1998-07-01

    Mixing times between methane and air under non-reacting or reacting conditions in the presence of rates of temperature and pressure and velocity gradients are examined using a mixing model based on the ideal gas law and the equation of continuity. The model is valid for low pressure combustors under non-reacting conditions. The model is also valid under reacting conditions for the fresh mixture which contains only trace amounts of combustion products. The effects of initial pressure, temperature and fluid composition on mixing time are also analyzed. In general, the exact mixing time has to be determined numerically. Nevertheless maximum values of mixing times can be determined analytically for a broad range of operational conditions. Results show that under both reacting and non-reacting conditions, the maximum mixing time is directly proportional to the initial pressure and temperature of mixture and inversely proportional to rates of pressure and temperature, and to velocity divergence. Mixing through fuel dispersion into the surrounding air is shown to be faster than via air penetration into the fuel flow. Rates of pressure of less than 1 atm/s acting along provide a mixing time in excess of one second which is unacceptably long for many applications, in particular gas turbine combustion. Rates of temperature produced by flame may provide mixing times shorter than 0.1 s. Mixing times of the order of a few milliseconds for efficient combustion and low emission, require high velocity gradients at the fuel-air boundary. Results show that enhanced mixing is achieved by combining temperature and velocity gradients. This analysis of mixing time is intended to provide important design guidelines for the development of high intensity, high efficiency and low emission combustors.

  10. Maximum likelihood clustering with dependent feature trees

    NASA Technical Reports Server (NTRS)

    Chittineni, C. B. (Principal Investigator)

    1981-01-01

    The decomposition of mixture density of the data into its normal component densities is considered. The densities are approximated with first order dependent feature trees using criteria of mutual information and distance measures. Expressions are presented for the criteria when the densities are Gaussian. By defining different typs of nodes in a general dependent feature tree, maximum likelihood equations are developed for the estimation of parameters using fixed point iterations. The field structure of the data is also taken into account in developing maximum likelihood equations. Experimental results from the processing of remotely sensed multispectral scanner imagery data are included.

  11. Improved maximum likelihood reconstruction of complex multi-generational pedigrees.

    PubMed

    Sheehan, Nuala A; Bartlett, Mark; Cussens, James

    2014-11-01

    The reconstruction of pedigrees from genetic marker data is relevant to a wide range of applications. Likelihood-based approaches aim to find the pedigree structure that gives the highest probability to the observed data. Existing methods either entail an exhaustive search and are hence restricted to small numbers of individuals, or they take a more heuristic approach and deliver a solution that will probably have high likelihood but is not guaranteed to be optimal. By encoding the pedigree learning problem as an integer linear program we can exploit efficient optimisation algorithms to construct pedigrees guaranteed to have maximal likelihood for the standard situation where we have complete marker data at unlinked loci and segregation of genes from parents to offspring is Mendelian. Previous work demonstrated efficient reconstruction of pedigrees of up to about 100 individuals. The modified method that we present here is not so restricted: we demonstrate its applicability with simulated data on a real human pedigree structure of over 1600 individuals. It also compares well with a very competitive approximate approach in terms of solving time and accuracy. In addition to identifying a maximum likelihood pedigree, we can obtain any number of pedigrees in decreasing order of likelihood. This is useful for assessing the uncertainty of a maximum likelihood solution and permits model averaging over high likelihood pedigrees when this would be appropriate. More importantly, when the solution is not unique, as will often be the case for large pedigrees, it enables investigation into the properties of maximum likelihood pedigree estimates which has not been possible up to now. Crucially, we also have a means of assessing the behaviour of other approximate approaches which all aim to find a maximum likelihood solution. Our approach hence allows us to properly address the question of whether a reasonably high likelihood solution that is easy to obtain is practically as

  12. Efficient white phosphorescent organic light-emitting diodes consisting of orange ultrathin and blue mixed host emission layers

    NASA Astrophysics Data System (ADS)

    Sheng, Ren; Zuo, Liangmei; Xue, Kaiwen; Duan, Yu; Chen, Ping; Cheng, Gang; Zhao, Yi

    2016-08-01

    We have successfully demonstrated highly efficient white phosphorescent organic light-emitting diodes (OLEDs) by inserting an ultrathin non-doped orange layer within blue mixed host emission layer. The key feature of the novel device is the employment of blue mixed host and orange ultrathin layers, resulting in an extended recombination region and more balanced charge carrier. The maximum efficiencies of 33.8 lm W‑1 and 32.2 cd A‑1 are obtained. Moreover, the resulting white device achieves a slight efficiency roll-off and a high luminance at low operating voltage. Our versatile concept suggests a promising simple method to achieve high performance white OLEDs.

  13. Efficient white phosphorescent organic light-emitting diodes consisting of orange ultrathin and blue mixed host emission layers

    NASA Astrophysics Data System (ADS)

    Sheng, Ren; Zuo, Liangmei; Xue, Kaiwen; Duan, Yu; Chen, Ping; Cheng, Gang; Zhao, Yi

    2016-08-01

    We have successfully demonstrated highly efficient white phosphorescent organic light-emitting diodes (OLEDs) by inserting an ultrathin non-doped orange layer within blue mixed host emission layer. The key feature of the novel device is the employment of blue mixed host and orange ultrathin layers, resulting in an extended recombination region and more balanced charge carrier. The maximum efficiencies of 33.8 lm W-1 and 32.2 cd A-1 are obtained. Moreover, the resulting white device achieves a slight efficiency roll-off and a high luminance at low operating voltage. Our versatile concept suggests a promising simple method to achieve high performance white OLEDs.

  14. Iowa Women of Achievement.

    ERIC Educational Resources Information Center

    Ohrn, Deborah Gore, Ed.

    1993-01-01

    This issue of the Goldfinch highlights some of Iowa's 20th century women of achievement. These women have devoted their lives to working for human rights, education, equality, and individual rights. They come from the worlds of politics, art, music, education, sports, business, entertainment, and social work. They represent Native Americans,…

  15. Achieving Peace through Education.

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    While it is generally agreed that peace is desirable, there are barriers to achieving a peaceful world. These barriers are classified into three major areas: (1) an erroneous view of human nature; (2) injustice; and (3) fear of world unity. In a discussion of these barriers, it is noted that although the consciousness and conscience of the world…

  16. Increasing Male Academic Achievement

    ERIC Educational Resources Information Center

    Jackson, Barbara Talbert

    2008-01-01

    The No Child Left Behind legislation has brought greater attention to the academic performance of American youth. Its emphasis on student achievement requires a closer analysis of assessment data by school districts. To address the findings, educators must seek strategies to remedy failing results. In a mid-Atlantic district of the Unites States,…

  17. Leadership Issues: Raising Achievement.

    ERIC Educational Resources Information Center

    Horsfall, Chris, Ed.

    This document contains five papers examining the meaning and operation of leadership as a variable affecting student achievement in further education colleges in the United Kingdom. "Introduction" (Chris Horsfall) discusses school effectiveness studies' findings regarding the relationship between leadership and effective schools, distinguishes…

  18. Achievements or Disasters?

    ERIC Educational Resources Information Center

    Goodwin, MacArthur

    2000-01-01

    Focuses on policy issues that have affected arts education in the twentieth century, such as: interest in discipline-based arts education, influence of national arts associations, and national standards and coordinated assessment. States that whether the policy decisions are viewed as achievements or disasters are for future determination. (CMK)

  19. Achieving True Consensus.

    ERIC Educational Resources Information Center

    Napier, Rod; Sanaghan, Patrick

    2002-01-01

    Uses the example of Vermont's Middlebury College to explore the challenges and possibilities of achieving consensus about institutional change. Discusses why, unlike in this example, consensus usually fails, and presents four demands of an effective consensus process. Includes a list of "test" questions on successful collaboration. (EV)

  20. School Students' Science Achievement

    ERIC Educational Resources Information Center

    Shymansky, James; Wang, Tzu-Ling; Annetta, Leonard; Everett, Susan; Yore, Larry D.

    2013-01-01

    This paper is a report of the impact of an externally funded, multiyear systemic reform project on students' science achievement on a modified version of the Third International Mathematics and Science Study (TIMSS) test in 33 small, rural school districts in two Midwest states. The systemic reform effort utilized a cascading leadership strategy…

  1. Essays on Educational Achievement

    ERIC Educational Resources Information Center

    Ampaabeng, Samuel Kofi

    2013-01-01

    This dissertation examines the determinants of student outcomes--achievement, attainment, occupational choices and earnings--in three different contexts. The first two chapters focus on Ghana while the final chapter focuses on the US state of Massachusetts. In the first chapter, I exploit the incidence of famine and malnutrition that resulted to…

  2. Assessing Handwriting Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    Teachers in the school setting need to emphasize quality handwriting across the curriculum. Quality handwriting means that the written content is easy to read in either manuscript or cursive form. Handwriting achievement can be assessed, but not compared to the precision of assessing basic addition, subtraction, multiplication, and division facts.…

  3. Intelligence and Educational Achievement

    ERIC Educational Resources Information Center

    Deary, Ian J.; Strand, Steve; Smith, Pauline; Fernandes, Cres

    2007-01-01

    This 5-year prospective longitudinal study of 70,000+ English children examined the association between psychometric intelligence at age 11 years and educational achievement in national examinations in 25 academic subjects at age 16. The correlation between a latent intelligence trait (Spearman's "g"from CAT2E) and a latent trait of educational…

  4. Explorations in achievement motivation

    NASA Technical Reports Server (NTRS)

    Helmreich, Robert L.

    1982-01-01

    Recent research on the nature of achievement motivation is reviewed. A three-factor model of intrinsic motives is presented and related to various criteria of performance, job satisfaction and leisure activities. The relationships between intrinsic and extrinsic motives are discussed. Needed areas for future research are described.

  5. NCLB: Achievement Robin Hood?

    ERIC Educational Resources Information Center

    Bracey, Gerald W.

    2008-01-01

    In his "Wall Street Journal" op-ed on the 25th of anniversary of "A Nation At Risk", former assistant secretary of education Chester E. Finn Jr. applauded the report for turning U.S. education away from equality and toward achievement. It was not surprising, then, that in mid-2008, Finn arranged a conference to examine the potential "Robin Hood…

  6. Achieving All Our Ambitions

    ERIC Educational Resources Information Center

    Hartley, Tricia

    2009-01-01

    National learning and skills policy aims both to build economic prosperity and to achieve social justice. Participation in higher education (HE) has the potential to contribute substantially to both aims. That is why the Campaign for Learning has supported the ambition to increase the proportion of the working-age population with a Level 4…

  7. INTELLIGENCE, PERSONALITY AND ACHIEVEMENT.

    ERIC Educational Resources Information Center

    MUIR, R.C.; AND OTHERS

    A LONGITUDINAL DEVELOPMENTAL STUDY OF A GROUP OF MIDDLE CLASS CHILDREN IS DESCRIBED, WITH EMPHASIS ON A SEGMENT OF THE RESEARCH INVESTIGATING THE RELATIONSHIP OF ACHIEVEMENT, INTELLIGENCE, AND EMOTIONAL DISTURBANCE. THE SUBJECTS WERE 105 CHILDREN AGED FIVE TO 6.3 ATTENDING TWO SCHOOLS IN MONTREAL. EACH CHILD WAS ASSESSED IN THE AREAS OF…

  8. SALT and Spelling Achievement.

    ERIC Educational Resources Information Center

    Nelson, Joan

    A study investigated the effects of suggestopedic accelerative learning and teaching (SALT) on the spelling achievement, attitudes toward school, and memory skills of fourth-grade students. Subjects were 20 male and 28 female students from two self-contained classrooms at Kennedy Elementary School in Rexburg, Idaho. The control classroom and the…

  9. Appraising Reading Achievement.

    ERIC Educational Resources Information Center

    Ediger, Marlow

    To determine quality sequence in pupil progress, evaluation approaches need to be used which guide the teacher to assist learners to attain optimally. Teachers must use a variety of procedures to appraise student achievement in reading, because no one approach is adequate. Appraisal approaches might include: (1) observation and subsequent…

  10. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Maximum rates. 9701.312 Section 9701.312 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN...

  11. Teaching Media Studies in Maximum Security Prisons.

    ERIC Educational Resources Information Center

    Corcoran, Farrel

    Some of the difficulties involved in teaching inside maximum security prisons, and ways a media studies teacher met these challenges, are described in this paper. The first section of the paper deals with the prison security system and the stresses it can cause for both teacher and student, while the second section discusses the influence of the…

  12. Maximum phonation time: variability and reliability.

    PubMed

    Speyer, Renée; Bogaardt, Hans C A; Passos, Valéria Lima; Roodenburg, Nel P H D; Zumach, Anne; Heijnen, Mariëlle A M; Baijens, Laura W J; Fleskens, Stijn J H M; Brunings, Jan W

    2010-05-01

    The objective of the study was to determine maximum phonation time reliability as a function of the number of trials, days, and raters in dysphonic and control subjects. Two groups of adult subjects participated in this reliability study: a group of outpatients with functional or organic dysphonia versus a group of healthy control subjects matched by age and gender. Over a period of maximally 6 weeks, three video recordings were made of five subjects' maximum phonation time trials. A panel of five experts were responsible for all measurements, including a repeated measurement of the subjects' first recordings. Patients showed significantly shorter maximum phonation times compared with healthy controls (on average, 6.6 seconds shorter). The averaged interclass correlation coefficient (ICC) over all raters per trial for the first day was 0.998. The averaged reliability coefficient per rater and per trial for repeated measurements of the first day's data was 0.997, indicating high intrarater reliability. The mean reliability coefficient per day for one trial was 0.939. When using five trials, the reliability increased to 0.987. The reliability over five trials for a single day was 0.836; for 2 days, 0.911; and for 3 days, 0.935. To conclude, the maximum phonation time has proven to be a highly reliable measure in voice assessment. A single rater is sufficient to provide highly reliable measurements.

  13. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 3 2013-01-01 2013-01-01 false Maximum rates. 9701.312 Section 9701.312 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN...

  14. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 3 2014-01-01 2014-01-01 false Maximum rates. 9701.312 Section 9701.312 Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN...

  15. Weak scale from the maximum entropy principle

    NASA Astrophysics Data System (ADS)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2015-03-01

    The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.

  16. Maximum entropy analysis of hydraulic pipe networks

    NASA Astrophysics Data System (ADS)

    Waldrip, Steven H.; Niven, Robert K.; Abel, Markus; Schlegel, Michael

    2014-12-01

    A Maximum Entropy (MaxEnt) method is developed to infer mean external and internal flow rates and mean pressure gradients (potential differences) in hydraulic pipe networks, without or with sufficient constraints to render the system deterministic. The proposed method substantially extends existing methods for the analysis of flow networks (e.g. Hardy-Cross), applicable only to deterministic networks.

  17. 5 CFR 9701.312 - Maximum rates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Administrative Personnel DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM (DEPARTMENT OF HOMELAND SECURITY-OFFICE OF PERSONNEL MANAGEMENT) DEPARTMENT OF HOMELAND SECURITY HUMAN RESOURCES MANAGEMENT SYSTEM Pay and Pay Administration Overview of Pay System § 9701.312 Maximum rates. (a) DHS may...

  18. Comparing maximum pressures in internal combustion engines

    NASA Technical Reports Server (NTRS)

    Sparrow, Stanwood W; Lee, Stephen M

    1922-01-01

    Thin metal diaphragms form a satisfactory means for comparing maximum pressures in internal combustion engines. The diaphragm is clamped between two metal washers in a spark plug shell and its thickness is chosen such that, when subjected to explosion pressure, the exposed portion will be sheared from the rim in a short time.

  19. Minimal length, Friedmann equations and maximum density

    NASA Astrophysics Data System (ADS)

    Awad, Adel; Ali, Ahmed Farag

    2014-06-01

    Inspired by Jacobson's thermodynamic approach [4], Cai et al. [5, 6] have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar-Cai derivation [6] of Friedmann equations to accommodate a general entrop-yarea law. Studying the resulted Friedmann equations using a specific entropy-area law, which is motivated by the generalized uncertainty principle (GUP), reveals the existence of a maximum energy density closed to Planck density. Allowing for a general continuous pressure p( ρ, a) leads to bounded curvature invariants and a general nonsingular evolution. In this case, the maximum energy density is reached in a finite time and there is no cosmological evolution beyond this point which leaves the big bang singularity inaccessible from a spacetime prospective. The existence of maximum energy density and a general nonsingular evolution is independent of the equation of state and the spacial curvature k. As an example we study the evolution of the equation of state p = ωρ through its phase-space diagram to show the existence of a maximum energy which is reachable in a finite time.

  20. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... quantity of potable water, or an anticipated acute shortage or significant decline, cannot exceed $150,000... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not to exceed $500,000 may be made to alleviate a significant decline in quantity or quality of...

  1. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... quantity of potable water, or an anticipated acute shortage or significant decline, cannot exceed $150,000... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not to exceed $500,000 may be made to alleviate a significant decline in quantity or quality of...

  2. 7 CFR 1778.11 - Maximum grants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... quantity of potable water, or an anticipated acute shortage or significant decline, cannot exceed $150,000... (CONTINUED) EMERGENCY AND IMMINENT COMMUNITY WATER ASSISTANCE GRANTS § 1778.11 Maximum grants. (a) Grants not to exceed $500,000 may be made to alleviate a significant decline in quantity or quality of...

  3. Maximum Possible Transverse Velocity in Special Relativity.

    ERIC Educational Resources Information Center

    Medhekar, Sarang

    1991-01-01

    Using a physical picture, an expression for the maximum possible transverse velocity and orientation required for that by a linear emitter in special theory of relativity has been derived. A differential calculus method is also used to derive the expression. (Author/KR)

  4. 24 CFR 200.15 - Maximum mortgage.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Maximum mortgage. 200.15 Section 200.15 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR HOUSING-FEDERAL HOUSING COMMISSIONER, DEPARTMENT OF HOUSING AND...

  5. Maximum rotation frequency of strange stars

    SciTech Connect

    Zdunik, J.L.; Haensel, P. )

    1990-07-15

    Using the MIT bag model of strange-quark matter, we calculate the maximum angular frequency of the uniform rotation of strange stars. After studying a broad range of the MIT bag-model parameters, we obtain an upper bound of 12.3 kHz.

  6. Agricultural costs of the Chesapeake Bay total maximum daily load.

    PubMed

    Kaufman, Zach; Abler, David; Shortle, James; Harper, Jayson; Hamlett, James; Feather, Peter

    2014-12-16

    This study estimates costs to agricultural producers of the Watershed Implementation Plans (WIPs) developed by states in the Chesapeake Bay Watershed to comply with the Chesapeake Bay total maximum daily load (TMDL) and potential cost savings that could be realized by a more efficient selection of agricultural Best Management Practices (BMPs) and spatial targeting of BMP implementation. The cost of implementing the WIPs between 2011 and 2025 is estimated to be about $3.6 billion (in 2010 dollars). The annual cost associated with full implementation of all WIP BMPs from 2025 onward is about $900 million. Significant cost savings can be realized through careful and efficient BMP selection and spatial targeting. If retiring up to 25% of current agricultural land is included as an option, Bay-wide cost savings of about 60% could be realized compared to the WIPs. PMID:25405490

  7. Agricultural costs of the Chesapeake Bay total maximum daily load.

    PubMed

    Kaufman, Zach; Abler, David; Shortle, James; Harper, Jayson; Hamlett, James; Feather, Peter

    2014-12-16

    This study estimates costs to agricultural producers of the Watershed Implementation Plans (WIPs) developed by states in the Chesapeake Bay Watershed to comply with the Chesapeake Bay total maximum daily load (TMDL) and potential cost savings that could be realized by a more efficient selection of agricultural Best Management Practices (BMPs) and spatial targeting of BMP implementation. The cost of implementing the WIPs between 2011 and 2025 is estimated to be about $3.6 billion (in 2010 dollars). The annual cost associated with full implementation of all WIP BMPs from 2025 onward is about $900 million. Significant cost savings can be realized through careful and efficient BMP selection and spatial targeting. If retiring up to 25% of current agricultural land is included as an option, Bay-wide cost savings of about 60% could be realized compared to the WIPs.

  8. High-efficiency silicon solar-cell design and practical barriers

    NASA Technical Reports Server (NTRS)

    Mokashi, A.

    1985-01-01

    A numerical evaluation technique is used to study the impact of practical barriers, such as heavy doping effects (Auger recombination, band gap narrowing), surface recombination, shadowing losses and minority-carrier lifetime (Tau), on a high efficiency silicon solar cell performance. Considering a high Tau of 1 ms, efficiency of a silicon solar cell of the hypothetical case is estimated to be around 29%. This is comparable with (detailed balance limit) maximum efficiency of a p-n junction solar cell of 30%. Value of Tau is varied from 1 second to 20 micro. Heavy doping effects, and realizable values of surface recombination velocities and shadowing, are then considered in succession and their influence on cell efficiency is evaluated and quantified. These practical barriers cause the cell efficiency to reduce from the maximum value of 29% to the experimentally achieved value of about 19%. Improvement in open circuit voltage V sub oc is required to achieve cell efficiency greater than 20%. Increased value of Tau reduces reverse saturation current and, hence, improves V sub oc. Control of surface recombination losses becomes critical at higher V sub oc. Substantial improvement in Tau and considerable reduction in surface recombination velocities is essential to achieve cell efficiencies greater than 20%.

  9. Project ACHIEVE final report

    SciTech Connect

    1997-06-13

    Project ACHIEVE was a math/science academic enhancement program aimed at first year high school Hispanic American students. Four high schools -- two in El Paso, Texas and two in Bakersfield, California -- participated in this Department of Energy-funded program during the spring and summer of 1996. Over 50 students, many of whom felt they were facing a nightmare future, were given the opportunity to work closely with personal computers and software, sophisticated calculators, and computer-based laboratories -- an experience which their regular academic curriculum did not provide. Math and science projects, exercises, and experiments were completed that emphasized independent and creative applications of scientific and mathematical theories to real world problems. The most important outcome was the exposure Project ACHIEVE provided to students concerning the college and technical-field career possibilities available to them.

  10. Exact parallel maximum clique algorithm for general and protein graphs.

    PubMed

    Depolli, Matjaž; Konc, Janez; Rozman, Kati; Trobec, Roman; Janežič, Dušanka

    2013-09-23

    A new exact parallel maximum clique algorithm MaxCliquePara, which finds the maximum clique (the fully connected subgraph) in undirected general and protein graphs, is presented. First, a new branch and bound algorithm for finding a maximum clique on a single computer core, which builds on ideas presented in two published state of the art sequential algorithms is implemented. The new sequential MaxCliqueSeq algorithm is faster than the reference algorithms on both DIMACS benchmark graphs as well as on protein-derived product graphs used for protein structural comparisons. Next, the MaxCliqueSeq algorithm is parallelized by splitting the branch-and-bound search tree to multiple cores, resulting in MaxCliquePara algorithm. The ability to exploit all cores efficiently makes the new parallel MaxCliquePara algorithm markedly superior to other tested algorithms. On a 12-core computer, the parallelization provides up to 2 orders of magnitude faster execution on the large DIMACS benchmark graphs and up to an order of magnitude faster execution on protein product graphs. The algorithms are freely accessible on http://commsys.ijs.si/~matjaz/maxclique.

  11. Theoretical Analysis of Maximum Flow Declination Rate versus Maximum Area Declination Rate in Phonation

    ERIC Educational Resources Information Center

    Titze, Ingo R.

    2006-01-01

    Purpose: Maximum flow declination rate (MFDR) in the glottis is known to correlate strongly with vocal intensity in voicing. This declination, or negative slope on the glottal airflow waveform, is in part attributable to the maximum area declination rate (MADR) and in part to the overall inertia of the air column of the vocal tract (lungs to…

  12. 50 CFR 259.34 - Minimum and maximum deposits; maximum time to deposit.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 11 2013-10-01 2013-10-01 false Minimum and maximum deposits; maximum time to deposit. 259.34 Section 259.34 Wildlife and Fisheries NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE AID TO FISHERIES...

  13. Developability assessment of clinical drug products with maximum absorbable doses.

    PubMed

    Ding, Xuan; Rose, John P; Van Gelder, Jan

    2012-05-10

    Maximum absorbable dose refers to the maximum amount of an orally administered drug that can be absorbed in the gastrointestinal tract. Maximum absorbable dose, or D(abs), has proved to be an important parameter for quantifying the absorption potential of drug candidates. The purpose of this work is to validate the use of D(abs) in a developability assessment context, and to establish appropriate protocol and interpretation criteria for this application. Three methods for calculating D(abs) were compared by assessing how well the methods predicted the absorption limit for a set of real clinical candidates. D(abs) was calculated for these clinical candidates by means of a simple equation and two computer simulation programs, GastroPlus and an program developed at Eli Lilly and Company. Results from single dose escalation studies in Phase I clinical trials were analyzed to identify the maximum absorbable doses for these compounds. Compared to the clinical results, the equation and both simulation programs provide conservative estimates of D(abs), but in general D(abs) from the computer simulations are more accurate, which may find obvious advantage for the simulations in developability assessment. Computer simulations also revealed the complex behavior associated with absorption saturation and suggested in most cases that the D(abs) limit is not likely to be achieved in a typical clinical dose range. On the basis of the validation findings, an approach is proposed for assessing absorption potential, and best practices are discussed for the use of D(abs) estimates to inform clinical formulation development strategies.

  14. The maximum intelligible range of the human voice

    NASA Astrophysics Data System (ADS)

    Boren, Braxton

    This dissertation examines the acoustics of the spoken voice at high levels and the maximum number of people that could hear such a voice unamplified in the open air. In particular, it examines an early auditory experiment by Benjamin Franklin which sought to determine the maximum intelligible crowd for the Anglican preacher George Whitefield in the eighteenth century. Using Franklin's description of the experiment and a noise source on Front Street, the geometry and diffraction effects of such a noise source are examined to more precisely pinpoint Franklin's position when Whitefield's voice ceased to be intelligible. Based on historical maps, drawings, and prints, the geometry and material of Market Street is constructed as a computer model which is then used to construct an acoustic cone tracing model. Based on minimal values of the Speech Transmission Index (STI) at Franklin's position, Whitefield's on-axis Sound Pressure Level (SPL) at 1 m is determined, leading to estimates centering around 90 dBA. Recordings are carried out on trained actors and singers to determine their maximum time-averaged SPL at 1 m. This suggests that the greatest average SPL achievable by the human voice is 90-91 dBA, similar to the median estimates for Whitefield's voice. The sites of Whitefield's largest crowds are acoustically modeled based on historical evidence and maps. Based on Whitefield's SPL, the minimal STI value, and the crowd's background noise, this allows a prediction of the minimally intelligible area for each site. These yield maximum crowd estimates of 50,000 under ideal conditions, while crowds of 20,000 to 30,000 seem more reasonable when the crowd was reasonably quiet and Whitefield's voice was near 90 dBA.

  15. Maximum independent set on diluted triangular lattices

    NASA Astrophysics Data System (ADS)

    Fay, C. W., IV; Liu, J. W.; Duxbury, P. M.

    2006-05-01

    Core percolation and maximum independent set on random graphs have recently been characterized using the methods of statistical physics. Here we present a statistical physics study of these problems on bond diluted triangular lattices. Core percolation critical behavior is found to be consistent with the standard percolation values, though there are strong finite size effects. A transfer matrix method is developed and applied to find accurate values of the density and degeneracy of the maximum independent set on lattices of limited width but large length. An extrapolation of these results to the infinite lattice limit yields high precision results, which are tabulated. These results are compared to results found using both vertex based and edge based local probability recursion algorithms, which have proven useful in the analysis of hard computational problems, such as the satisfiability problem.

  16. Maximum-entropy description of animal movement.

    PubMed

    Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M

    2015-03-01

    We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.

  17. Maximum constrained sparse coding for image representation

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Zhao, Danpei; Jiang, Zhiguo

    2015-12-01

    Sparse coding exhibits good performance in many computer vision applications by finding bases which capture highlevel semantics of the data and learning sparse coefficients in terms of the bases. However, due to the fact that bases are non-orthogonal, sparse coding can hardly preserve the samples' similarity, which is important for discrimination. In this paper, a new image representing method called maximum constrained sparse coding (MCSC) is proposed. Sparse representation with more active coefficients means more similarity information, and the infinite norm is added to the solution for this purpose. We solve the optimizer by constraining the codes' maximum and releasing the residual to other dictionary atoms. Experimental results on image clustering show that our method can preserve the similarity of adjacent samples and maintain the sparsity of code simultaneously.

  18. Zipf's law, power laws and maximum entropy

    NASA Astrophysics Data System (ADS)

    Visser, Matt

    2013-04-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.

  19. Model Fit after Pairwise Maximum Likelihood

    PubMed Central

    Barendse, M. T.; Ligtvoet, R.; Timmerman, M. E.; Oort, F. J.

    2016-01-01

    Maximum likelihood factor analysis of discrete data within the structural equation modeling framework rests on the assumption that the observed discrete responses are manifestations of underlying continuous scores that are normally distributed. As maximizing the likelihood of multivariate response patterns is computationally very intensive, the sum of the log–likelihoods of the bivariate response patterns is maximized instead. Little is yet known about how to assess model fit when the analysis is based on such a pairwise maximum likelihood (PML) of two–way contingency tables. We propose new fit criteria for the PML method and conduct a simulation study to evaluate their performance in model selection. With large sample sizes (500 or more), PML performs as well the robust weighted least squares analysis of polychoric correlations. PMID:27148136

  20. Pareto versus lognormal: A maximum entropy test

    NASA Astrophysics Data System (ADS)

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2011-08-01

    It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.

  1. Finding maximum colorful subtrees in practice.

    PubMed

    Rauf, Imran; Rasche, Florian; Nicolas, François; Böcker, Sebastian

    2013-04-01

    In metabolomics and other fields dealing with small compounds, mass spectrometry is applied as a sensitive high-throughput technique. Recently, fragmentation trees have been proposed to automatically analyze the fragmentation mass spectra recorded by such instruments. Computationally, this leads to the problem of finding a maximum weight subtree in an edge-weighted and vertex-colored graph, such that every color appears, at most once in the solution. We introduce new heuristics and an exact algorithm for this Maximum Colorful Subtree problem and evaluate them against existing algorithms on real-world and artificial datasets. Our tree completion heuristic consistently scores better than other heuristics, while the integer programming-based algorithm produces optimal trees with modest running times. Our fast and accurate heuristic can help determine molecular formulas based on fragmentation trees. On the other hand, optimal trees from the integer linear program are useful if structure is relevant, for example for tree alignments.

  2. A Maximum Radius for Habitable Planets.

    PubMed

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope. PMID:26159097

  3. Evaluation of the Maximum Allowable Cost Program

    PubMed Central

    Lee, A. James; Hefner, Dennis; Dobson, Allen; Hardy, Ralph

    1983-01-01

    This article summarizes an evaluation of the Maximum Allowable Cost (MAC)-Estimated Acquisition Cost (EAC) program, the Federal Government's cost-containment program for prescription drugs.1 The MAC-EAC regulations which became effective on August 26, 1976, have four major components: (1) Maximum Allowable Cost reimbursement limits for selected multisource or generically available drugs; (2) Estimated Acquisition Cost reimbursement limits for all drugs; (3) “usual and customary” reimbursement limits for all drugs; and (4) a directive that professional fee studies be performed by each State. The study examines the benefits and costs of the MAC reimbursement limits for 15 dosage forms of five multisource drugs and EAC reimbursement limits for all drugs for five selected States as of 1979. PMID:10309857

  4. Pareto versus lognormal: a maximum entropy test.

    PubMed

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2011-08-01

    It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.

  5. Maximum hydrocarbon window determination in South Louisiana

    SciTech Connect

    Leach, W.G. )

    1993-03-29

    This is the third and final part of a three part article about the distribution of hydrocarbons in the Tertiary sands of South Louisiana. Based on many individual plots, it was found that hydrocarbon distribution will vary according to the depth of abnormal pressure and lithology. The relation of maximum hydrocarbon distribution to formation fracture strength or depth opens the door to the use of a maximum hydrocarbon window (MHW) technique. This MHW technique can be used as a decision making tool on how deep to drill a well, particularly how deep to drill a well below the top of abnormal pressure. The paper describes the benefits of the MHW technique and its future potential for exploration and development operations.

  6. A Maximum Radius for Habitable Planets.

    PubMed

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

  7. Design strategies for achieving high triplet energy electron transporting host materials for blue electrophosphorescence

    SciTech Connect

    Sapochak, Linda S.; Padmaperuma, Asanga B.; Vecchi, Paul A.; Qiao, Hong; Burrows, Paul E.

    2006-12-01

    High efficiency small molecule organic light emitting devices (OLEDs) based on light emission from an electrophosphorescent dopant dispersed in an organic host matrix are well known. Achieving blue phosphorescent OLEDs is particularly challenging because the host triplet energy should ideally be > 2.8 eV to prevent back-transfer of energy from the dopant to the host matrix resulting in loss of efficiency. A design strategy for developing new host materials with high triplet energies by using phosphine oxide (P=O) moieties as points of saturation in order to build sublimable, electron transporting host materials starting from small, wide bandgap molecular building blocks (i.e., biphenyl, phenyl, naphthalene, octafluorobiphenyl, and N-ethylcarbazole) is described. Electrophosphorescent OLEDs using the organic phosphine oxide compounds as host materials for the sky blue organometallic phosphor, iridium(III)bis(4,6-(di-fluorophenyl)-pyridinato-N,C2’) picolinate (FIrpic) give maximum external quantum efficiencies of ~ 8% and maximum luminance power efficiencies up to 25 lm/W.

  8. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Steigerwald, Robert L; Sabate, Juan A; Chi, Song; McCann, Adam J; Zhang, Li; Mueller, Frank

    2012-09-01

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  9. 5 CFR 534.203 - Maximum stipends.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... training program Maximums by grade and step 1 L-A Below high school graduation GS-1-1 (minus 3 steps). L-1... year postgraduate predoctoral GS-7-1 (minus 3 steps). L-6 Third year medical school GS-7-1 (minus 3 steps). L-7 Third year postgraduate predoctoral GS-9-1 (minus 3 steps). L-7 Fourth year medical...

  10. 5 CFR 534.203 - Maximum stipends.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... training program Maximums by grade and step 1 L-A Below high school graduation GS-1-1 (minus 3 steps). L-1... year postgraduate predoctoral GS-7-1 (minus 3 steps). L-6 Third year medical school GS-7-1 (minus 3 steps). L-7 Third year postgraduate predoctoral GS-9-1 (minus 3 steps). L-7 Fourth year medical...

  11. 5 CFR 534.203 - Maximum stipends.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... training program Maximums by grade and step 1 L-A Below high school graduation GS-1-1 (minus 3 steps). L-1... year postgraduate predoctoral GS-7-1 (minus 3 steps). L-6 Third year medical school GS-7-1 (minus 3 steps). L-7 Third year postgraduate predoctoral GS-9-1 (minus 3 steps). L-7 Fourth year medical...

  12. 5 CFR 534.203 - Maximum stipends.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... training program Maximums by grade and step 1 L-A Below high school graduation GS-1-1 (minus 3 steps). L-1... year postgraduate predoctoral GS-7-1 (minus 3 steps). L-6 Third year medical school GS-7-1 (minus 3 steps). L-7 Third year postgraduate predoctoral GS-9-1 (minus 3 steps). L-7 Fourth year medical...

  13. Tissue radiation response with maximum Tsallis entropy.

    PubMed

    Sotolongo-Grau, O; Rodríguez-Pérez, D; Antoranz, J C; Sotolongo-Costa, Oscar

    2010-10-01

    The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature. PMID:21230944

  14. Maximum privacy without coherence, zero-error

    NASA Astrophysics Data System (ADS)

    Leung, Debbie; Yu, Nengkun

    2016-09-01

    We study the possible difference between the quantum and the private capacities of a quantum channel in the zero-error setting. For a family of channels introduced by Leung et al. [Phys. Rev. Lett. 113, 030512 (2014)], we demonstrate an extreme difference: the zero-error quantum capacity is zero, whereas the zero-error private capacity is maximum given the quantum output dimension.

  15. Tissue Radiation Response with Maximum Tsallis Entropy

    SciTech Connect

    Sotolongo-Grau, O.; Rodriguez-Perez, D.; Antoranz, J. C.; Sotolongo-Costa, Oscar

    2010-10-08

    The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.

  16. Maximum entropy and Bayesian methods. Proceedings.

    NASA Astrophysics Data System (ADS)

    Grandy, W. T., Jr.; Schick, L. H.

    This volume contains a selection of papers presented at the Tenth Annual Workshop on Maximum Entropy and Bayesian Methods. The thirty-six papers included cover a wide range of applications in areas such as economics and econometrics, astronomy and astrophysics, general physics, complex systems, image reconstruction, and probability and mathematics. Together they give an excellent state-of-the-art overview of fundamental methods of data analysis.

  17. Tissue radiation response with maximum Tsallis entropy.

    PubMed

    Sotolongo-Grau, O; Rodríguez-Pérez, D; Antoranz, J C; Sotolongo-Costa, Oscar

    2010-10-01

    The expression of survival factors for radiation damaged cells is currently based on probabilistic assumptions and experimentally fitted for each tumor, radiation, and conditions. Here, we show how the simplest of these radiobiological models can be derived from the maximum entropy principle of the classical Boltzmann-Gibbs expression. We extend this derivation using the Tsallis entropy and a cutoff hypothesis, motivated by clinical observations. The obtained expression shows a remarkable agreement with the experimental data found in the literature.

  18. Maximum-biomass prediction of homofermentative Lactobacillus.

    PubMed

    Cui, Shumao; Zhao, Jianxin; Liu, Xiaoming; Chen, Yong Q; Zhang, Hao; Chen, Wei

    2016-07-01

    Fed-batch and pH-controlled cultures have been widely used for industrial production of probiotics. The aim of this study was to systematically investigate the relationship between the maximum biomass of different homofermentative Lactobacillus and lactate accumulation, and to develop a prediction equation for the maximum biomass concentration in such cultures. The accumulation of the end products and the depletion of nutrients by various strains were evaluated. In addition, the minimum inhibitory concentrations (MICs) of acid anions for various strains at pH 7.0 were examined. The lactate concentration at the point of complete inhibition was not significantly different from the MIC of lactate for all of the strains, although the inhibition mechanism of lactate and acetate on Lactobacillus rhamnosus was different from the other strains which were inhibited by the osmotic pressure caused by acid anions at pH 7.0. When the lactate concentration accumulated to the MIC, the strains stopped growing. The maximum biomass was closely related to the biomass yield per unit of lactate produced (YX/P) and the MIC (C) of lactate for different homofermentative Lactobacillus. Based on the experimental data obtained using different homofermentative Lactobacillus, a prediction equation was established as follows: Xmax - X0 = (0.59 ± 0.02)·YX/P·C. PMID:26896862

  19. Maximum saliency bias in binocular fusion

    NASA Astrophysics Data System (ADS)

    Lu, Yuhao; Stafford, Tom; Fox, Charles

    2016-07-01

    Subjective experience at any instant consists of a single ("unitary"), coherent interpretation of sense data rather than a "Bayesian blur" of alternatives. However, computation of Bayes-optimal actions has no role for unitary perception, instead being required to integrate over every possible action-percept pair to maximise expected utility. So what is the role of unitary coherent percepts, and how are they computed? Recent work provided objective evidence for non-Bayes-optimal, unitary coherent, perception and action in humans; and further suggested that the percept selected is not the maximum a posteriori percept but is instead affected by utility. The present study uses a binocular fusion task first to reproduce the same effect in a new domain, and second, to test multiple hypotheses about exactly how utility may affect the percept. After accounting for high experimental noise, it finds that both Bayes optimality (maximise expected utility) and the previously proposed maximum-utility hypothesis are outperformed in fitting the data by a modified maximum-salience hypothesis, using unsigned utility magnitudes in place of signed utilities in the bias function.

  20. "SPURS" in the North Atlantic Salinity Maximum

    NASA Astrophysics Data System (ADS)

    Schmitt, Raymond

    2014-05-01

    The North Atlantic Salinity Maximum is the world's saltiest open ocean salinity maximum and was the focus of the recent Salinity Processes Upper-ocean Regional Study (SPURS) program. SPURS was a joint venture between US, French, Irish, and Spanish investigators. Three US and two EU cruises were involved from August, 1012 - October, 2013 as well as surface moorings, glider, drifter and float deployments. Shipboard operations included underway meteorological and oceanic data, hydrographic surveys and turbulence profiling. The goal is to improve our understanding of how the salinity maximum is maintained and how it may be changing. It is formed by an excess of evaporation over precipitation and the wind-driven convergence of the subtropical gyre. Such salty areas are getting saltier with global warming (a record high SSS was observed in SPURS) and it is imperative to determine the relative roles of surface water fluxes and oceanic processes in such trends. The combination of accurate surface flux estimates with new assessments of vertical and horizontal mixing in the ocean will help elucidate the utility of ocean salinity in quantifying the changing global water cycle.

  1. The relative performance of targeted maximum likelihood estimators.

    PubMed

    Porter, Kristin E; Gruber, Susan; van der Laan, Mark J; Sekhon, Jasjeet S

    2011-01-01

    There is an active debate in the literature on censored data about the relative performance of model based maximum likelihood estimators, IPCW-estimators, and a variety of double robust semiparametric efficient estimators. Kang and Schafer (2007) demonstrate the fragility of double robust and IPCW-estimators in a simulation study with positivity violations. They focus on a simple missing data problem with covariates where one desires to estimate the mean of an outcome that is subject to missingness. Responses by Robins, et al. (2007), Tsiatis and Davidian (2007), Tan (2007) and Ridgeway and McCaffrey (2007) further explore the challenges faced by double robust estimators and offer suggestions for improving their stability. In this article, we join the debate by presenting targeted maximum likelihood estimators (TMLEs). We demonstrate that TMLEs that guarantee that the parametric submodel employed by the TMLE procedure respects the global bounds on the continuous outcomes, are especially suitable for dealing with positivity violations because in addition to being double robust and semiparametric efficient, they are substitution estimators. We demonstrate the practical performance of TMLEs relative to other estimators in the simulations designed by Kang and Schafer (2007) and in modified simulations with even greater estimation challenges. PMID:21931570

  2. Does achievement motivation mediate the semantic achievement priming effect?

    PubMed

    Engeser, Stefan; Baumann, Nicola

    2014-10-01

    The aim of our research was to understand the processes of the prime-to-behavior effects with semantic achievement primes. We extended existing models with a perspective from achievement motivation theory and additionally used achievement primes embedded in the running text of excerpts of school textbooks to simulate a more natural priming condition. Specifically, we proposed that achievement primes affect implicit achievement motivation and conducted pilot experiments and 3 main experiments to explore this proposition. We found no reliable positive effect of achievement primes on implicit achievement motivation. In light of these findings, we tested whether explicit (instead of implicit) achievement motivation is affected by achievement primes and found this to be the case. In the final experiment, we found support for the assumption that higher explicit achievement motivation implies that achievement priming affects the outcome expectations. The implications of the results are discussed, and we conclude that primes affect achievement behavior by heightening explicit achievement motivation and outcome expectancies. PMID:24820250

  3. Highly efficient blue and warm white organic light-emitting diodes with a simplified structure

    NASA Astrophysics Data System (ADS)

    Li, Xiang-Long; Ouyang, Xinhua; Chen, Dongcheng; Cai, Xinyi; Liu, Ming; Ge, Ziyi; Cao, Yong; Su, Shi-Jian

    2016-03-01

    Two blue fluorescent emitters were utilized to construct simplified organic light-emitting diodes (OLEDs) and the remarkable difference in device performance was carefully illustrated. A maximum current efficiency of 4.84 cd A-1 (corresponding to a quantum efficiency of 4.29%) with a Commission Internationale de l’Eclairage (CIE) coordinate of (0.144, 0.127) was achieved by using N,N-diphenyl-4″-(1-phenyl-1H-benzo[d]imidazol-2-yl)-[1, 1‧:4‧, 1″-terphenyl]-4-amine (BBPI) as a non-doped emission layer of the simplified blue OLEDs without carrier-transport layers. In addition, simplified fluorescent/phosphorescent (F/P) hybrid warm white OLEDs without carrier-transport layers were fabricated by utilizing BBPI as (1) the blue emitter and (2) the host of a complementary yellow phosphorescent emitter (PO-01). A maximum current efficiency of 36.8 cd A-1 and a maximum power efficiency of 38.6 lm W-1 were achieved as a result of efficient energy transfer from the host to the guest and good triplet exciton confinement on the phosphorescent molecules. The blue and white OLEDs are among the most efficient simplified fluorescent blue and F/P hybrid white devices, and their performance is even comparable to that of most previously reported complicated multi-layer devices with carrier-transport layers.

  4. Approaching the ground states of the random maximum two-satisfiability problem by a greedy single-spin flipping process

    NASA Astrophysics Data System (ADS)

    Ma, Hui; Zhou, Haijun

    2011-05-01

    In this brief report we explore the energy landscapes of two spin glass models using a greedy single-spin flipping process, Gmax. The ground-state energy density of the random maximum two-satisfiability problem is efficiently approached by Gmax. The achieved energy density e(t) decreases with the evolution time t as e(t)-e(∞)=h(log10t)-z with a small prefactor h and a scaling coefficient z>1, indicating an energy landscape with deep and rugged funnel-shape regions. For the ±J Viana-Bray spin glass model, however, the greedy single-spin dynamics quickly gets trapped to a local minimal region of the energy landscape.

  5. Techniques of Efficient Reading.

    ERIC Educational Resources Information Center

    Brown, James I.

    To help students develop techniques which lead to maximum reading efficiency, it is first necessary to help them develop a positive self-image. Growing evidence is focusing attention on self-image as the crucial determiner of progress. Poor progess in reading at the elementary level leads to poor self-image, which in turn hinders the student in…

  6. Middle Holocene thermal maximum in eastern Beringia

    NASA Astrophysics Data System (ADS)

    Kaufman, D. S.; Bartlein, P. J.

    2015-12-01

    A new systematic review of diverse Holocene paleoenvironmental records (Kaufman et al., Quat. Sci. Rev., in revision) has clarified the primary multi-centennial- to millennial-scale trends across eastern Beringia (Alaska, westernmost Canada and adjacent seas). Composite time series from midges, pollen, and biogeochemical indicators are compared with new summaries of mountain-glacier and lake-level fluctuations, terrestrial water-isotope records, sea-ice and sea-surface-temperature analyses, and peatland and thaw-lake initiation frequencies. The paleo observations are also compared with recently published simulations (Bartlein et al., Clim. Past Discuss., 2015) that used a regional climate model to simulate the effects of global and regional-scale forcings at 11 and 6 ka. During the early Holocene (11.5-8 ka), rather than a prominent thermal maximum as suggested previously, the newly compiled paleo evidence (mostly sensitive to summer conditions) indicates that temperatures were highly variable, at times both higher and lower than present, although the overall lowest average temperatures occurred during the earliest Holocene. During the middle Holocene (8-4 ka), glaciers retreated as the regional average temperature increased to a maximum between 7 and 5 ka, as reflected in most proxy types. The paleo evidence for low and variable temperatures during the early Holocene contrasts with more uniformly high temperatures during the middle Holocene and agrees with the climate simulations, which show that temperature in eastern Beringia was on average lower at 11 ka and higher at 6 ka than at present (pre-industrial). Low temperatures during the early Holocene can be attributed in part to the summer chilling caused by flooding the continental shelves, whereas the mid-Holocene thermal maximum was likely driven by the loss of the Laurentide ice sheet, rise in greenhouse gases, higher-than-present summer insolation, and expansion of forest over tundra.

  7. Fabrication of High power, High-Efficiency Linear Array Diode Lasers by Pulse Anodic Oxidation

    NASA Astrophysics Data System (ADS)

    Gao, Xin; Zhang, Jing; Li, Hui; Qu, Yi; Bo, Baoxue

    2006-09-01

    InGaAlAs/AlGaAs/GaAs double-quantum-well (DQW) linear array diode lasers with asymmetric wide waveguide have been successfully fabricated by pulse anodic oxidation upon molecular beam epitaxy material growth. High-efficiency and high-power quasi-continuous-wave (QCW) output has been realized at 808 nm wavelength. The threshold current and slope efficiency of the prepared high-fill-factor QCW devices are 24 A and 1.25 A/W, respectively, and a maximum wall-plug efficiency of 51% has been achieved.

  8. Maximum aposteriori joint source/channel coding

    NASA Technical Reports Server (NTRS)

    Sayood, Khalid; Gibson, Jerry D.

    1991-01-01

    A maximum aposteriori probability (MAP) approach to joint source/channel coder design is presented in this paper. This method attempts to explore a technique for designing joint source/channel codes, rather than ways of distributing bits between source coders and channel coders. For a nonideal source coder, MAP arguments are used to design a decoder which takes advantage of redundancy in the source coder output to perform error correction. Once the decoder is obtained, it is analyzed with the purpose of obtaining 'desirable properties' of the channel input sequence for improving overall system performance. Finally, an encoder design which incorporates these properties is proposed.

  9. Dynamical maximum entropy approach to flocking

    NASA Astrophysics Data System (ADS)

    Cavagna, Andrea; Giardina, Irene; Ginelli, Francesco; Mora, Thierry; Piovani, Duccio; Tavarone, Raffaele; Walczak, Aleksandra M.

    2014-04-01

    We derive a new method to infer from data the out-of-equilibrium alignment dynamics of collectively moving animal groups, by considering the maximum entropy model distribution consistent with temporal and spatial correlations of flight direction. When bird neighborhoods evolve rapidly, this dynamical inference correctly learns the parameters of the model, while a static one relying only on the spatial correlations fails. When neighbors change slowly and the detailed balance is satisfied, we recover the static procedure. We demonstrate the validity of the method on simulated data. The approach is applicable to other systems of active matter.

  10. Multiperiod Maximum Loss is time unit invariant.

    PubMed

    Kovacevic, Raimund M; Breuer, Thomas

    2016-01-01

    Time unit invariance is introduced as an additional requirement for multiperiod risk measures: for a constant portfolio under an i.i.d. risk factor process, the multiperiod risk should equal the one period risk of the aggregated loss, for an appropriate choice of parameters and independent of the portfolio and its distribution. Multiperiod Maximum Loss over a sequence of Kullback-Leibler balls is time unit invariant. This is also the case for the entropic risk measure. On the other hand, multiperiod Value at Risk and multiperiod Expected Shortfall are not time unit invariant. PMID:27563531

  11. Maximum profit performance of an absorption refrigerator

    SciTech Connect

    Chen, L.; Sun, F.; Wu, C.

    1996-12-01

    The operation of an absorption refrigerator is viewed as a production process with exergy as its output. The relations between the optimal profit and COP (coefficient of performance), and the COP bound at the maximum profit of the refrigerator are derived based on a general heat transfer law. The results provide a theoretical basis for developing and utilizing a variety of absorption refrigerators. The focus of this paper is to search the compromise optimization between economics (profit) and the utilization factor (COP) for finite-time endoreversible thermodynamic cycles.

  12. Maximum Temperature Detection System for Integrated Circuits

    NASA Astrophysics Data System (ADS)

    Frankiewicz, Maciej; Kos, Andrzej

    2015-03-01

    The paper describes structure and measurement results of the system detecting present maximum temperature on the surface of an integrated circuit. The system consists of the set of proportional to absolute temperature sensors, temperature processing path and a digital part designed in VHDL. Analogue parts of the circuit where designed with full-custom technique. The system is a part of temperature-controlled oscillator circuit - a power management system based on dynamic frequency scaling method. The oscillator cooperates with microprocessor dedicated for thermal experiments. The whole system is implemented in UMC CMOS 0.18 μm (1.8 V) technology.

  13. Maximum a posteriori decoder for digital communications

    NASA Technical Reports Server (NTRS)

    Altes, Richard A. (Inventor)

    1997-01-01

    A system and method for decoding by identification of the most likely phase coded signal corresponding to received data. The present invention has particular application to communication with signals that experience spurious random phase perturbations. The generalized estimator-correlator uses a maximum a posteriori (MAP) estimator to generate phase estimates for correlation with incoming data samples and for correlation with mean phases indicative of unique hypothesized signals. The result is a MAP likelihood statistic for each hypothesized transmission, wherein the highest value statistic identifies the transmitted signal.

  14. Achieving closure at Fernald

    SciTech Connect

    Bradburne, John; Patton, Tisha C.

    2001-02-25

    When Fluor Fernald took over the management of the Fernald Environmental Management Project in 1992, the estimated closure date of the site was more than 25 years into the future. Fluor Fernald, in conjunction with DOE-Fernald, introduced the Accelerated Cleanup Plan, which was designed to substantially shorten that schedule and save taxpayers more than $3 billion. The management of Fluor Fernald believes there are three fundamental concerns that must be addressed by any contractor hoping to achieve closure of a site within the DOE complex. They are relationship management, resource management and contract management. Relationship management refers to the interaction between the site and local residents, regulators, union leadership, the workforce at large, the media, and any other interested stakeholder groups. Resource management is of course related to the effective administration of the site knowledge base and the skills of the workforce, the attraction and retention of qualified a nd competent technical personnel, and the best recognition and use of appropriate new technologies. Perhaps most importantly, resource management must also include a plan for survival in a flat-funding environment. Lastly, creative and disciplined contract management will be essential to effecting the closure of any DOE site. Fluor Fernald, together with DOE-Fernald, is breaking new ground in the closure arena, and ''business as usual'' has become a thing of the past. How Fluor Fernald has managed its work at the site over the last eight years, and how it will manage the new site closure contract in the future, will be an integral part of achieving successful closure at Fernald.

  15. Maximum neighborhood margin criterion in face recognition

    NASA Astrophysics Data System (ADS)

    Han, Pang Ying; Teoh, Andrew Beng Jin

    2009-04-01

    Feature extraction is a data analysis technique devoted to removing redundancy and extracting the most discriminative information. In face recognition, feature extractors are normally plagued with small sample size problems, in which the total number of training images is much smaller than the image dimensionality. Recently, an optimized facial feature extractor, maximum marginal criterion (MMC), was proposed. MMC computes an optimized projection by solving the generalized eigenvalue problem in a standard form that is free from inverse matrix operation, and thus it does not suffer from the small sample size problem. However, MMC is essentially a linear projection technique that relies on facial image pixel intensity to compute within- and between-class scatters. The nonlinear nature of faces restricts the discrimination of MMC. Hence, we propose an improved MMC, namely maximum neighborhood margin criterion (MNMC). Unlike MMC, which preserves global geometric structures that do not perfectly describe the underlying face manifold, MNMC seeks a projection that preserves local geometric structures via neighborhood preservation. This objective function leads to the enhancement of classification capability, and this is testified by experimental results. MNMC shows its performance superiority compared to MMC, especially in pose, illumination, and expression (PIE) and face recognition grand challenge (FRGC) databases.

  16. Maximum Likelihood Analysis in the PEN Experiment

    NASA Astrophysics Data System (ADS)

    Lehman, Martin

    2013-10-01

    The experimental determination of the π+ -->e+ ν (γ) decay branching ratio currently provides the most accurate test of lepton universality. The PEN experiment at PSI, Switzerland, aims to improve the present world average experimental precision of 3 . 3 ×10-3 to 5 ×10-4 using a stopped beam approach. During runs in 2008-10, PEN has acquired over 2 ×107 πe 2 events. The experiment includes active beam detectors (degrader, mini TPC, target), central MWPC tracking with plastic scintillator hodoscopes, and a spherical pure CsI electromagnetic shower calorimeter. The final branching ratio will be calculated using a maximum likelihood analysis. This analysis assigns each event a probability for 5 processes (π+ -->e+ ν , π+ -->μ+ ν , decay-in-flight, pile-up, and hadronic events) using Monte Carlo verified probability distribution functions of our observables (energies, times, etc). A progress report on the PEN maximum likelihood analysis will be presented. Work supported by NSF grant PHY-0970013.

  17. Probably maximum flood of the Sava River

    NASA Astrophysics Data System (ADS)

    Brilly, Mitja; Vidmar, Andrej; Raj, Mojca Å.

    2010-05-01

    The Nuclear Power Plant Krško (NEK) situated on the left bank of the Save River close to the border of Croatia. Probably Maximum Flood, on the location of the NEK could result in combination of probably maximum precipitation, sequential storm before PMP or snowmelt on the Sava River watershed. Mediterranean climate characterises very high precipitation and temporary high snow pack. The HBV-96 model as Integrated Hydrological Modelling System (IHMS) used for modelling. Model was calibrated and verification for daily time step at first for time period 1190-2006. Calibration and verification for hourly time step was done for period 1998-1999. The stream routing parameters were calibrated for flood event in years 1998 and 2007 and than verification for flood event in 1990. Discharge routing data analysis shown that possible inundation of Ljubljana and Savinja valley was not properly estimated. The flood areas are protected with levees and water does not spread over flooded areas in events used for calibration. Inundated areas in Ljubljana valley and Savinja valley are protected by levees and model could not simulate properly inundation of PMF. We recalibrate parameters controlled inundation on those areas for the worst scenario. Calculated PMF values drop down tramendosly after recalibration.

  18. Effect of fiber and matrix maximum strain on the energy absorption of composite materials

    NASA Technical Reports Server (NTRS)

    Farley, G. L.

    1985-01-01

    Static crushing tests were conducted on graphite composite tubes to examine the influence of fiber and matrix maximum strain at failure on the energy absorption capability of graphite reinforced composite material. Fiber and matrix maximum strain at failure were determined to significantly effect energy absorption. The higher strain at failure composite material system, AS-4/5245, exhibited superior energy absorption capability compared to AS-4/934, T300/5245 or T300/934 composite material. Results of this investigation suggest that to achieve maximum energy absorption from a composite material a matrix material that has a higher strain at failure than the fiber reinforcement should be used.

  19. Achieving TASAR Operational Readiness

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    2015-01-01

    NASA has been developing and testing the Traffic Aware Strategic Aircrew Requests (TASAR) concept for aircraft operations featuring a NASA-developed cockpit automation tool, the Traffic Aware Planner (TAP), which computes traffic/hazard-compatible route changes to improve flight efficiency. The TAP technology is anticipated to save fuel and flight time and thereby provide immediate and pervasive benefits to the aircraft operator, as well as improving flight schedule compliance, passenger comfort, and pilot and controller workload. Previous work has indicated the potential for significant benefits for TASAR-equipped aircraft, and a flight trial of the TAP software application in the National Airspace System has demonstrated its technical viability. This paper reviews previous and ongoing activities to prepare TASAR for operational use.

  20. Organizing a Practice Session for Maximum Effectiveness

    ERIC Educational Resources Information Center

    DeGroot, Joanna

    2009-01-01

    According to Jason Paulk, director of choral activities at Eastern New Mexico University, progress is made during those in-between times and that progress magnifies with efficient time spent alone. Paulk is a firm believer in the importance of singers organizing their practice sessions, and he details some effective organization methods, including…