Energy Supply Rate Research Articles

RELATIONSHIP BETWEEN NEURODYNAMIC CHARACTERISTICS AND FUNCTIONAL PREPAREDNESS OF MUSCLES IN ATHLETES OF DIFFERENT SPORTS

Aim. The article is aimed at studying the relationship between the neurodynamic characteristics of athletes of different sports and the indicators of physical fitness obtained during exercise tests. Materials and methods. The study involved male athletes aged 16–21 years, involved in swimming (20 people) and powerlifting (16 people), having sports ranks from the 2nd adult to a candidate for master of sports. The volume and concentration of attention, the speed of eye-hand coordination, the level of functional mobility, the strength of nervous processes, the response to a moving object and the tapping test were processed using an automated program. Indicators of aerobic and speed - strength fitness of the muscles of the lower extremities were determined by the cycle ergo meter tests. Results. Swimmers differed from power lifters by a smaller volume, but better concentration of attention, higher dynamism and strength of nervous processes, less pronounced excitement in the central nervous system, high rates of aerobic energy supply and a less pronounced correlation between the functional indicators and psychophysiological characteristics. In both groups, negative correlations of aerobic performance with the speed of visual motor responses and positive correlations with the balance of nervous processes were revealed. Speed-strength indicators are better for athletes with a high functional mobility, dynamism and strength of nervous processes. Conclusion. There is a correlation between the neurodynamic characteristics and indicators of functional fitness, which must be taken into account when interpreting the results of stress tests and developing individual recommendations based on the results of the examination.

A unified model to optimize configuration of battery energy storage systems with multiple types of batteries

Aiming to minimize the total cost of hybrid power system (HPS), a mathematical model for the configuration of battery energy storage system (BESS) with multiple types of batteries was proposed. The effects of battery types and capacity degradation characteristics on the optimal capacity configurations of the BESS and power scheduling schemes of the HPS were investigated. The effectiveness of the proposed model was verified and illustrated through a case study of a HPS with photovoltaic-wind-biomass-batteries. Results show that the optimal configuration of the BESS can be obtained by solving the proposed model, including the types and the capacities of batteries, and the power scheduling schemes of the batteries. For the integration of the HPS, the BESS with multiple types of batteries has certain economic advantages when compared with the BESS with a single type of batteries. In addition, the types and capacities of batteries in the BESS and the relative power scheduling schemes would change with the electricity curtailment rate of the renewable energy supply of HPS. The total cost of the HPS can be reduced at the expense of a certain amount of renewable energy supply.

GONG p-Mode Parameters Through Two Solar Cycles

We investigate the parameters of global solar p-mode oscillations, namely damping width Gamma, amplitude A, mean squared velocity langle v^{2}rangle, energy E, and energy supply rate mathrm{d}E/mathrm{d}t, derived from two solar cycles’ worth (1996 – 2018) of Global Oscillation Network Group (GONG) time series for harmonic degrees l=0,mbox{--},150. We correct for the effect of fill factor, apparent solar radius, and spurious jumps in the mode amplitudes. We find that the amplitude of the activity-related changes of Gamma and A depends on both frequency and harmonic degree of the modes, with the largest variations of Gamma for modes with 2400~upmumbox{Hz}lenule3300~upmumbox{Hz} and 31le l le60 with a minimum-to-maximum variation of 26.6pm0.3% and of A for modes with 2400~upmumbox{Hz}lenule 3300~upmumbox{Hz} and 61le l le100 with a minimum-to-maximum variation of 27.4pm0.4%. The level of correlation between the solar radio flux F_{10.7} and mode parameters also depends on mode frequency and harmonic degree. As a function of mode frequency, the mode amplitudes are found to follow an asymmetric Voigt profile with nu_{text{max}}=3073.59pm0.18~upmumbox{Hz}. From the mode parameters, we calculate physical mode quantities and average them over specific mode frequency ranges. In this way, we find that the mean squared velocities langle v^{2}rangle and energies E of p modes are anticorrelated with the level of activity, varying by 14.7pm0.3% and 18.4pm0.3%, respectively, and that the mode energy supply rates show no significant correlation with activity. With this study we expand previously published results on the temporal variation of solar p-mode parameters. Our results will be helpful to future studies of the excitation and damping of p modes, i.e., the interplay between convection, magnetic field, and resonant acoustic oscillations.

Indoor thermal environment due to non-steady-state radiation heat transfer of a capillary ceiling radiation cooling system

The capillary ceiling radiation cooling panel (C-CRCP) is a newly developed terminal device for air conditioning to provide indoor thermal comfort for occupants and to save energy. In this paper, numerical modelling of a room with a C-CRCP system was used to analyze radiant heat transfer under non-steady-state conditions. Experiments were conducted in an environmental chamber to verify simulation results. The chamber was equipped with a C-CRCP, which was covered with gypsumboard. The results showed that the inlet water temperature had a significant influence on ceiling surface temperature. The ceiling surface temperature and the steady-state time were increased with higher inlet water temperature. A vertical gradient in indoor air temperature was found. Ceiling surface temperature and indoor air temperature were increased with an increase in inlet air temperature. The energy supply rate of the radiant panel had a positive correlation with chilled water velocity. The amount of radiation was double the amount of convection, and the thickness of the gypsumboard had virtually no effect on the proportions of radiation and convection. The model was considered validated since the maximum relative errors between experimental data and simulation results of inlet water temperature and supply air conditions were within 10%.

Gibbs Energy Dynamic Yield Method (GEDYM): Predicting microbial growth yields under energy-limiting conditions

Biomass-explicit biogeochemical models assign microbial growth yields (Y) using values measured in the laboratory or predicted using thermodynamics-based methods. However, Y values are rarely measured under the low energy delivery conditions that often prevail in the subsurface, and existing predictive methods for calculating Y values when the catabolic energy supply rate is limited remain poorly tested. Here, we derive and validate a new semi-theoretical method for calculating Y values: the Gibbs Energy Dynamic Yield Method (GEDYM). Method validation relies on a compilation of 132 geochemically relevant literature Y values comprising predominantly (60%) low energy (> −25 kJ (mol e−)−1) metabolisms. GEDYM is based on estimating the Gibbs energy change of the metabolic reaction (ΔGmet), which links the Gibbs energy changes of the catabolic (ΔGcat) and anabolic (ΔGan) reactions of a microorganism through its growth yield. Given that the values of ΔGmet,ΔGcat and ΔGan all depend on their respective reaction quotients, the resulting Y values account for changes in the chemical environment surrounding the cells. GEDYM incorporates an empirical relationship that accurately estimates the extent to which ΔGmet deviates from its standard state value from the relative difference between ΔGcat and its corresponding standard state value. GEDYM yields Y values with lower relative errors and statistical bias than the existing Gibbs energy dissipation method (GEDM). Using dissimilatory iron reduction, sulfate reduction and methanogenesis as examples, we illustrate the importance of considering variations in ΔGcat and ΔGan when predicting Y values for individual metabolisms. Because of its ability to dynamically adjust the values of ΔGmet and Y to variable geochemical conditions, GEDYM yields a more realistic representation of geomicrobial activity in predictive reactive transport models.

Computer-Aided Design and Simulation of a Membrane Bioreactor for Produced Water Treatment

Membrane Bio Reactor (MBR) has been designed and simulation for the treatment of Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), Total Organic Carbon (TOC), Total Dissolved Solid (TDS) and Oil/ Grease in produced water at a capacity of 54.1778 kg/hr for removal of 95%-99% contaminants. The MBR design equations were developed using the law of conservation of mass to determine the dimensions and functional parameters. The developed performance equations were integrated numerically using fourth-order Runge-Kutta embedded in MATLAB computer program to determine the optimum range of values of the reactor functional dimensions and functional parameters. The effect of rate of energy supply per reactor volume and substrate specific rate constant on the capacity of the membrane bioreactor were investigated. Also, the effect of initial loading of substrate on Solid Retention Time (SRT) was also investigated. Results showed that kinetic parameters influenced the percentage removal of contaminants as Hydraulic Retention Time (HRT) and size of MBR decreased with increase in specific rate constant at fixed conversion of contaminants. Also, HRT and MBR size increased as the conversion of Chemical Oxygen Demand (COD) was increased, while increased in the ratio of energy supplied per volume resulted in decreased of MBR volume. The effect of initial loading of substrate on SRT showed that increased in substrate loading increased the retention time of the solid at fixed substrate conversion, while the conversion of substrate to microorganism increased as the solid retention time was increased. The increased in initial loading of substrate concentration increased the production of Mixed Liquor Suspended Solids (MLSS). Thus, the size of MBR required for the conversion of the investigated contaminants at the design percentage removal increased in the following order: oil/grease < TSS < TOC < TDS. The MBR volume, height and HRT were 1.10 and 5.29 m3; 0.98 and 4.68 m; and 1.38 and 6.62 at 95% and 99% respectively, while the SRT was 82.67 days.

Energy demand and supply in human skeletal muscle.

The energy required for muscle contraction is provided by the breakdown of ATP but the amount of ATP in muscles cells is sufficient to power only a short duration of contraction. Buffering of ATP by phosphocreatine, a reaction catalysed by creatine kinase, extends the duration of activity possible but sustained activity depends on continual regeneration of PCr. This is achieved using ATP generated by oxidative processes and, during intense activity, by anaerobic glycolysis. The rate of ATP breakdown ranges from 70 to 140mM min-1 during isometric contractions of various intensity to as much as 400mM min-1 during intense, dynamic activity. The maximum rate of oxidative energy supply in untrained people is ~50mM min-1 which, if the contraction duty cycle is 0.5 as is often the case in cyclic activity, is sufficient to match an ATP breakdown rate during contraction of 100mM min-1. During brief, intense activity the rate of ATP turnover can exceed the rates of PCr regeneration by combined oxidative and glycolytic energy supply, resulting in a net decrease in PCr concentration. Glycolysis has the capacity to produce between 30 and 50mM of ATP so that, for example, anaerobic glycolysis could provide ATP at an average of 100mM min-1 over 30s of exhausting activity. The creatine kinase reaction plays an important role not only in buffering ATP but also in communicating energy demand from sites of ATP breakdown to the mitochondria. In that role, creatine kinases acts to slow and attenuate the response of mitochondria to changes in energy demand.

Exploring the Feasibility of Low-Carbon Scenarios Using Historical Energy Transitions Analysis

The scenarios generated by energy systems models provide a picture of the range of possible pathways to a low-carbon future. However, in order to be truly useful, these scenarios should not only be possible but also plausible. In this paper, we have used lessons from historical energy transitions to create a set of diagnostic tests to assess the feasibility of an example 2 °C scenario (generated using the least cost optimization model, TIAM-Grantham). The key assessment criteria included the rate of deployment of low carbon technologies and the rate of transition between primary energy resources. The rates of deployment of key low-carbon technologies were found to exceed the maximum historically observed rate of deployment of 20% per annum. When constraints were added to limit the scenario to within historically observed rates of change, the model no longer solved for 2 °C. Under these constraints, the lowest median 2100 temperature change for which a solution was found was about 2.1 °C and at more than double the cumulative cost of the unconstrained scenario. The analysis in this paper highlights the considerable challenge of meeting 2 °C, requiring rates of energy supply technology deployment and rates of declines in fossil fuels which are unprecedented.

Classical investigation of long-range coherence in biological systems.

Almost five decades ago, H. Fröhlich [H. Fröhlich, "Long-range coherence and energy storage in biological systems," Int. J. Quantum Chem. 2(5), 641-649 (1968)] reported, on a theoretical basis, that the excitation of quantum modes of vibration in contact with a thermal reservoir may lead to steady states, where under high enough rate of energy supply, only specific low-frequency modes of vibration are strongly excited. This nonlinear phenomenon was predicted to occur in biomolecular systems, which are known to exhibit complex vibrational spectral properties, especially in the terahertz frequency domain. However, since the effects of terahertz or lower-frequency modes are mainly classical at physiological temperatures, there are serious doubts that Fröhlich's quantum description can be applied to predict such a coherent behavior in a biological environment, as suggested by the author. In addition, a quantum formalism makes the phenomenon hard to investigate using realistic molecular dynamics simulations (MD) as they are usually based on the classical principles. In the current paper, we provide a general classical Hamiltonian description of a nonlinear open system composed of many degrees of freedom (biomolecular structure) excited by an external energy source. It is shown that a coherent behaviour similar to Fröhlich's effect is to be expected in the classical case for a given range of parameter values. Thus, the supplied energy is not completely thermalized but stored in a highly ordered fashion. The connection between our Hamiltonian description, carried out in the space of normal modes, and a more standard treatment in the physical space is emphasized in order to facilitate the prediction of the effect from MD simulations. It is shown how such a coherent phenomenon may induce long-range resonance effects that could be of critical importance at the biomolecular level. The present work is motivated by recent experimental evidences of long-lived excited low-frequency modes in protein structures, which were reported as a consequence of the Fröhlich's effect.

Solar cell as wings of different sizes for flapping-wing micro air vehicles

Currently, the biggest challenge for flapping-wing micro air vehicles is their very short flight duration due to limited on-board energy storage capacity. To overcome this challenge, a concept of solar-cell-flapping-wing micro air vehicle is herein proposed and studied. Thirty-three types of currently successful flapping-wing micro air vehicles (including insect-like, bird-like, and hummingbird-like flapping-wing micro air vehicles) are analyzed to explore scaling laws of flapping-wing micro air vehicles. The influences of wingspan, wing area, flapping frequency, and power on mass of flapping-wing micro air vehicles are studied. A dynamic energy harvesting model of solar-cell-flapping-wing is built up and utilized to formulate energy supply rate equations of three types of flapping-wing micro air vehicles. Considering the averaged ground solar spectral irradiance and today’s energy conversion efficiency of solar cells, the variation of energy supply rate by scales is analyzed. Several critical parameters to design an efficient long duration flapping-wing micro air vehicle are suggested.

Melting of aluminum with ideal or defect lattice: Molecular dynamics simulations with accounting of electronic heat conductivity

In this work, the atomistic simulations of rapid melting of aluminum are performed. We use the two-temperature approach separately describing the ionic and electronic subsystems of crystal. Both ideal and defect states of initial lattice are considered. The dependence of melting temperature on pressure is investigated in the simulations of thermal equilibrium establishment in the systems with plate interphase boundaries. Non-equilibrium melting of aluminum is studied in simulations with the constant rate of heat energy supply. The maximal temperatures of overheated material before complete melting are obtained in dependence of energy supply rate. Presence of initial defects of lattice substantially decreases the overheating of material. Electronic heat conductivity significantly accelerates the thermal equilibrium establishment in systems with interphase boundaries and decreases the drop of temperature after beginning of melting in the systems with constant rate of heating.

Mechanical and electromyographic responses during the 3-min all-out test in competitive cyclists

While the 3-min all-out test is an ideal exercise paradigm to study muscle fatigue during dynamic whole-body exercise, so far it has been used mainly to provide insight into the bioenergetic determinants of performance. To shed some light into the development of peripheral muscle fatigue during the 3-min all-out test, we investigated the time course of muscle-fibre conduction velocity (MFCV). Twelve well-trained cyclists (23±3yrs) performed an incremental test, a 3-min all-out familiarization trial and a 3-min all-out test. Surface electromyographic signals were detected from the vastus lateralis muscle of the dominant limb. MFCV decreased with power output, though with a somewhat different time course, and the two parameters were strongly correlated (r=0.87; P<0.001). A modest decrease in MFCV (17.7±4.8%), probably due to the endurance characteristics of the subjects, may help explain why a relatively high power output (79±8% of the peak power output of the incremental test; 60±14% of the difference between this peak value and the gas exchange threshold) was still maintained at the end of the test. These findings suggest that muscle fatigue substantially affects performance in the 3-min all-out test, expanding on the traditional bioenergetic explanation that performance is limited by rate and capacity of energy supply.

Solar cycle variations in the powers and damping rates of low-degree solar acoustic oscillations

Helioseismology uses the Sun’s natural resonant oscillations to study the solar interior. The properties of the solar oscillations are sensitive to the Sun’s magnetic activity cycle. Here we examine variations in the powers, damping rates, and energy supply rates of the most prominent acoustic oscillations in unresolved, Sun-as-a-star data, obtained by the Birmingham Solar Oscillations Network (BiSON) during solar cycles 22, 23, and the first half of 24. The variations in the helioseismic parameters are compared to the 10.7cm flux, a well-known global proxy of solar activity. As expected the oscillations are most heavily damped and the mode powers are at a minimum at solar activity maximum. The 10.7cm flux was linearly regressed using the fractional variations of damping rates and powers observed during cycle 23. In general, good agreement is found between the damping rates and the 10.7cm flux. However, the linearly regressed 10.7cm flux and fractional variation in powers diverge in cycles 22 and 24, indicating that the relationship between the mode powers and the 10.7cm flux is not consistent from one cycle to the next. The energy supply rate of the oscillations, which is usually approximately constant, also decreases at this time. We have determined that this discrepancy is not because of the first-order bias introduced by an increase in the level of background noise or gaps in the data. Although we cannot categorically rule out an instrumental origin, the divergence observed in cycle 24, when the data were of high quality and the data coverage was over 80%, raises the possibility that the effect may be solar in origin.

Catabolic rates, population sizes and doubling/replacement times of microorganisms in natural settings

Directly assessing the impact of subsurface microbial activity on global element cycles is complicated by the inaccessibility of most deep biospheres and the difficulty of growing representative cultivars in the laboratory. In order to constrain the rates of biogeochemical processes in such settings, a quantitative relationship between rates of microbial catalysis, energy supply and demand and population size has been developed that complements the limited biogeochemical data describing subsurface environments. Within this formulation, rates of biomass change are determined as a function of the proportion of catabolic power that is converted into anabolism—either new microorganisms or the replacement of existing cell components—and the amount of energy that is required to synthesize biomass. Catabolic power is related to biomass through an energy-based yield coefficient that takes into account the constraints that different environments impose on biomolecule synthesis; this method is compared to other approaches for determining yield coefficients. Furthermore, so-called microbial maintenance energies that have been reported in the literature, which span many orders of magnitude, are reviewed. The equations developed in this study are used to demonstrate the interrelatedness of catabolic reaction rates, Gibbs energy of reaction, maintenance energy, biomass yield coefficients, microbial population sizes and doubling/replacement times. The number of microorganisms that can be supported by particular combinations of energy supply and demand is illustrated as a function of the catabolic rates in marine environments. Replacement/doubling times for various population sizes are shown as well. Finally, cell count and geochemical data describing two marine sedimentary environments in the South Pacific Gyre and the Peru Margin are used to constrain in situ metabolic and catabolic rates. The formulations developed in this study can be used to better define the limits and extent of life because they are valid for any metabolism under any set of conditions.

Experimental analysis on Rowe’s stress-dilatancy relation and frictional instability of fault gouges

The stress-dilatancy relation is important for understanding fault mechanics and brittle deformation of rocks, and hence the onset of frictional instability. The principle of minimum energy ratio was proposed by Rowe, and this Rowe's theory has been applied to deformation of granular materials. Rowe suggested that the energy ratio, which is the ratio of the energy dissipation rate to energy supply rate, would be a minimum and constant value. The relation between the rate of dilatancy and the maximum stress ratio can be extended to the case of a random assembly of irregular particles whereby the rate of internal work absorbed in frictional heat is a minimum as the mass dilates. According to Rowe's law, experiments show that the minimum energy criterion is closely obeyed by highly dilatant dense over-consolidated and reloaded assemblies throughout deformation. However, it is unknown whether or not the principle of minimum energy ratio can be applied to fault mechanics. The results of our friction experiments show the possibility that the energy ratio can be a new factor for evaluating frictional instability.

Energy spectrum of buoyancy-driven turbulence.

Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Π(u), we demonstrate that, for stably stratified flows, the kinetic energy spectrum E(u)(k)∼k(-11/5), the potential energy spectrum E(θ)(k)∼k(-7/5), and Π(u)(k)∼k(-4/5) are consistent with the Bolgiano-Obukhov scaling. This scaling arises due to the conversion of kinetic energy to the potential energy by buoyancy. For weaker buoyancy, this conversion is weak, hence E(u)(k) follows Kolmogorov's spectrum with a constant energy flux. For Rayleigh-Bénard convection, we show that the energy supply rate by buoyancy is positive, which leads to an increasing Π(u)(k) with k, thus ruling out Bolgiano-Obukhov scaling for the convective turbulence. Our numerical results show that convective turbulence for unit Prandt number exhibits a constant Π(u)(k) and E(u)(k)∼k(-5/3) for a narrow band of wave numbers.

Ultrasonic energy in liposome production: process modelling and size calculation

The use of liposomes in several fields of biotechnology, as well as in pharmaceutical and food sciences is continuously increasing. Liposomes can be used as carriers for drugs and other active molecules. Among other characteristics, one of the main features relevant to their target applications is the liposome size. The size of liposomes, which is determined during the production process, decreases due to the addition of energy. The energy is used to break the lipid bilayer into smaller pieces, then these pieces close themselves in spherical structures. In this work, the mechanisms of rupture of the lipid bilayer and the formation of spheres were modelled, accounting for how the energy, supplied by ultrasonic radiation, is stored within the layers, as the elastic energy due to the curvature and as the tension energy due to the edge, and to account for the kinetics of the bending phenomenon. An algorithm to solve the model equations was designed and the relative calculation code was written. A dedicated preparation protocol, which involves active periods during which the energy is supplied and passive periods during which the energy supply is set to zero, was defined and applied. The model predictions compare well with the experimental results, by using the energy supply rate and the time constant as fitting parameters. Working with liposomes of different sizes as the starting point of the experiments, the key parameter is the ratio between the energy supply rate and the initial surface area.

Cassini observations reveal a regime of zonostrophic macroturbulence on Jupiter

In December 2000, the Cassini fly-by near Jupiter delivered high-resolution images of Jupiter’s clouds over the entire planet in a band between 50°N and 50°S. Three daily-averaged two-dimensional velocity snapshots extracted from these images are used to perform spectral analysis of jovian atmospheric macroturbulence. A similar analysis is also performed on alternative data documented by Choi and Showman (Choi, D., Showman, A. [2011]. Icarus 216, 597–609), based on a different method of image processing. The inter-comparison of the products of both analyses ensures a better constraint of the spectral estimates. Both analyses reveal strong anisotropy of the kinetic energy spectrum. The zonal spectrum is very steep and most of the kinetic energy resides in slowly evolving, alternating zonal (west–east) jets, while the non-zonal, or residual spectrum obeys the Kolmogorov–Kraichnan law specific to two-dimensional turbulence in the range of the inverse energy cascade. The spectral data is used to estimate the inverse cascade rate ∊ and the zonostrophy index Rβ for the first time. Although both datasets yield somewhat different values of ∊, it is estimated to be in the range 0.5–1.0×10−5m2s−3. The ensuing values of Rβ≳5 belong well in the range of zonostrophic turbulence whose threshold corresponds to Rβ≃2.5. We infer that the large-scale circulation is maintained by an anisotropic inverse energy cascade. The removal of the Great Red Spot from both datasets has no significant effect upon either the spectra or the inverse cascade rate. The spectral data are used to compute the rate of the energy exchange, W, between the non-zonal structures and the large-scale zonal flow. It is found that instantaneous values of W may exceed ∊ by an order of magnitude. Previous numerical simulations with a barotropic model suggest that W and ∊ attain comparable values only after averaging of W over a sufficiently long time. Near-instantaneous values of W that have been routinely used to infer the rate of the kinetic energy supply to Jupiter’s zonal flow may therefore significantly overestimate ∊. This disparity between W and ∊ may resolve the long-standing conundrum of an unrealistically high rate of energy transfer to the zonal flow. The meridional diffusivity Kϕ in the regime of zonostrophic turbulence is given by an expression that depends on ∊. The value of Kϕ estimated from the spectra is compared against data from the dispersion of stratospheric gases and debris resulting from the Shoemaker-Levy 9 comet and Wesley asteroid impacts in 1994 and 2009 respectively. Not only is Kϕ found to be consistent with estimates for both impacts, but the eddy diffusivity found from observations appears to be scale-independent. This behaviour could be a consequence of the interaction between anisotropic turbulence and Rossby waves specific to the regime of zonostrophic macroturbulence.

A modified active Brownian dynamics model using asymmetric energy conversion and its application to the molecular motor system

We consider a modified energy depot model in the overdamped limit using an asymmetric energy conversion rate, which consists of linear and quadratic terms in an active particle's velocity. In order to analyze our model, we adopt a system of molecular motors on a microtubule and employ a flashing ratchet potential synchronized to a stochastic energy supply. By performing an active Brownian dynamics simulation, we investigate effects of the active force, thermal noise, external load, and energy-supply rate. Our model yields the stepping and stalling behaviors of the conventional molecular motor. The active force is found to facilitate the forwardly processive stepping motion, while the thermal noise reduces the stall force by enhancing relatively the backward stepping motion under external loads. The stall force in our model decreases as the energy-supply rate is decreased. Hence, assuming the Michaelis-Menten relation between the energy-supply rate and the an ATP concentration, our model describes ATP-dependent stall force in contrast to kinesin-1.

Analysis of Economic Efficiency on Production of Wood Pellet in Korea

Recently, in order to encounter national energy security and climate change according to high oil prices and Convention on Climate Change, “Low Carbon Green Growth” is promoted as government wide policy and Korea has a plan to expand development and supply of self–supportable new & renewable energy resource strategically. In the National Energy Plan, it is planned to expand new renewable energy supply rate up to 11% and allocate 31% of this energy to bio energy (Ministry for Food, Agriculture, Forestry, and Fisheries, 2008). In development and supply of new & renewable energy, the wood pellet, a forest biomass, is evaluated as possible to create visible outcome in early stage and having relatively high contribution level in mid and long term. IPCC recommends to substitute bio energy for fossil fuel, assessing that among the alternatives of climate change, the forest had higher flexibility and cost effectiveness (Forest Service, 2010). Wood pellet is recognized as an effective alternative for substituting fossil fuel and reducing greenhouse gas and authorized as a carbon neutral alternative energy with no carbon emission in the Convention on Climate Change (Forest Service, 2009). Accordingly, Forest Service plans to substitute wood pellet for heating of 140,000 farm houses and 37% of controlled horticulture by 2020 and produce and supply 1 million ton of wood pellet using domestic materials through expansion of forest management product collection by establishing wood pellet energy utilization measures and domestic demand of the wood pellet is expected to increase continuously (Forest Service, 2010). Additionally, with Renewable Portfolio Standards (RPS) since 2012, it is prospected that future expansion of new renewable energy market will bring increase of demand on wood pellet. Although traditional new renewable energy market focused on solar and wind power, it is prospected that due to introduction of the RPS, new and renewable energy sources with higher RECs (Renewable Energy Certificates) weight, unit price competitive power, facility scalability and electric power generation efficiency will be selected (Korea Environment Institute, 2011). According to Samsung Economic Research Institute, it is expected that when evaluating with 2 axes of RECs weight and power generation efficiency and facility capacity, the market in marine wind power, tidal power, lignocelluloses biomass single firing power generation will be expanded (Samsung Economic Research Institute, 2011). Like this, while the demand of wood pellet is forecasted to continue to increase due to its supply expansion policy and related systems, it is actually difficult to expand and industrialize the supply of wood pellet without security of economical efficiency in its production. Besides for wood pellet related socioeconomic previous studies, Korea Forest Policy Research Association (2003) executed studies on economic efficiency, environmentality, and convenience of heating boiler system and the Ministry of Agriculture and Forestry (2005) conducted economic analysis on thermal energy production Analysis of Economic Efficiency on Production of Wood Pellet in Korea