295 research outputs found

    Analysis of Technological Portfolios for CO2 stabilizations and Effects of Technological Changes

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    In this study, cost-effective technological options to stabilize CO2 concentrations at 550, 500, and 450 ppmv are evaluated using a world energy systems model of linear programming with a high regional resolution. This model treats technological change endogenously for wind power, photovoltaics, and fuel-cell vehicles, which are technologies of mass production and are considered to follow the “learning by doing” process. Technological changes induced by climate policies are evaluated by maintaining the technological changes at the levels of the base case wherein there is no climate policy. The results achieved through model analyses include 1) cost-effective technological portfolios, including carbon capture and storage, marginal CO2 reduction costs, and increases in energy system cost for three levels of stabilization and 2) the effect of the induced technological change on the above mentioned factors. A sensitivity analysis is conducted with respect to the learning rate.Energy systems model, Global warming, Technological portfolios, Technological changes

    Crossover Time in Relative Fluctuations Characterizes the Longest Relaxation Time of Entangled Polymers

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    In entangled polymer systems, there are several characteristic time scales, such as the entanglement time and the disengagement time. In molecular simulations, the longest relaxation time (the disengagement time) can be determined by the mean square displacement (MSD) of a segment or by the shear relaxation modulus. Here, we propose the relative fluctuation analysis method, which is originally developed for characterizing large fluctuations, to determine the longest relaxation time from the center of mass trajectories of polymer chains (the time-averaged MSDs). Applying the method to simulation data of entangled polymers (by the slip-spring model and the simple reptation model), we provide a clear evidence that the longest relaxation time is estimated as the crossover time in the relative fluctuations.Comment: 17 pages, 9 figures, to appear in J. Chem. Phy

    Estimating relaxation times from a single trajectory

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    Complex systems such as protein conformational fluctuations and supercooled liquids exhibit a long relaxation time and are considered to posses multiple relaxation times. We analytically obtain the exact correlation function for stochastic processes with multiple relaxation times. We show that the time-averaged correlation function calculated by a trajectory whose length is shorter than the longest relaxation time exhibits an apparent aging behavior. We propose a method to extract relaxation times from a single trajectory. This method successfully extracts relaxation times of a stochastic process with multiple states when a state can be characterized by the values of the trajectory. As an application of this method, we estimate several relaxation times smaller than the longest relaxation time in conformational fluctuations of a small protein.Comment: 10 pages, 4 figure

    Designing an assessment system of buildings for all lifecycle stages based on the concept of eco-efficiency

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    CASBEE (Comprehensive Assessment System for Building Environmental Efficiency) is an environmental labeling method for buildings, based on assessment of the environmental performance of buildings. In CASBEE, BEE (Building Environmental Efficiency) was developed as a new indicator for assessment following the concept of eco-efficiency. With the increasing BEE value, the total environmental performance of buildings is labeled from the highest performance. The framework of basic and extended CASBEE tools as a structured assessment system is called the “CASBEE family”. CASBEE consists of a set of four basic assessment tools, namely “CASBEE for Pre-design” (CASBEE-PD), “CASBEE for New Construction” (CASBEE-NC), “CASBEE for Existing Building” (CASBEE-EB) and “CASBEE for Renovation” (CASBEE-RN). These correspond to the individual stages of the building's lifecycle. There are also needs for detailed assessment targeting specific environmental aspects. “CASBEE-HI,” as an extended tool, assesses efforts made in buildings to alleviate the heat island effect. A new tool called “CASBEE for Urban Development” (CASBEE-UD) is developed for assessment of a group of buildings. In Japan, approximately 500,000 detached houses are constructed every year. In order to improve the quality of houses, “CASBEE for Home” was introduced in 2007. Some local authorities introduced CASBEE into their building administration as assessment methods for their sustainable building reporting systems. This requires building owners to submit a planning document assessing the environmental performance of their buildings to the authorities. In April 2004, the city of Nagoya introduced “CASBEE Nagoya”. Introduction of CASBEE followed in the city of Osaka, Yokohama, Kyoto, and other municipals. These local systems require some modification in CASBEE to reflect their local characteristics, such as climate and prioritized policies

    Search for third generation vector leptoquarks in 1.96 TeV proton-antiproton collisions

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    The CDF experiment has searched for production of a third generation vector leptoquark (VLQ3) in the di-tau plus di-jet channel using 322 pb{sup -1} of Run II data. We review the production and decay theory and describe the VLQ3 model we have used as a benchmark. We study the analysis, including the data sample, triggers, particle identification, and event selection. We also discuss background estimates and systematic uncertainties. We have found no evidence for VLQ3 production and have set a 95% C.L. upper limit on the pair production cross section {sigma} to 344 fb, and exclude VLQ3 in the mass range m{sub VLQ3} > 317 GeV/c{sup 2}, assuming Yang-Mills couplings and Br(LQ3 {yields} b{tau}) = 1. If theoretical uncertainties on the cross section are taken into account, the results are {sigma} < 353 fb and m{sub VLQ3} > 303 GeV/c{sup 2}. For a VLQ3 with Minimal couplings, the upper limit on the cross section is {sigma} < 493 fb ({sigma} < 554 fb) and the lower limit on the mass is m{sub VLQ3} > 251 GeV/c{sup 2} (m{sub VLQ3} > 235 GeV/c{sup 2}) for the nominal (1{sigma} varied) theoretical expectation

    Stress responsive miR-23a attenuates skeletal muscle atrophy by targeting MAFbx /atrogin-1

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    Muscle atrophy occurs in many pathological states and results primarily from accelerated protein degradation by the ubiquitin-proteasome pathway. We used dexamethasone to induce muscle wasting and investigated the role of a microRNA (miRNA) in the control of muscle-specific E3 ubiquitin ligase MAFbx/atrogin-1. Here we show that miR-23a suppresses MAFbx/atrogin-1 translation by binding to 3'UTR of the mRNA. Furthermore, ectopic expression of miR-23a is sufficient to protect myocytes from atrophy in vitro and in vivo in response to dexamethasone treatment, and heat stress-induced miR-23a protects muscle from dexamethasone-induced muscle atrophy. Our surprising discovery of the physiological role of miR-23a in preventing the atrophy program should lay the basis not only for further understanding of the mechanisms of muscle wasting in diverse diseases, but also for developing novel therapies for these debilitating conditions

    Verification of Thermal Comfort of Combined Convection-Radiation Air Conditioning System using Building Structure

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    Combined Convection-Radiation Air Conditioning System using Building Structure combines the advantages of TABS and convection air conditioning. In ordinary TABS, pipes are buried in the frame, but here pipes are laid on the lower (ceiling) surface of the floor slab. Also, jets from a Convection-enhancing Spot fan are sprayed toward the ceiling surface, promoting convection on the frame surface. This airflow promotes timely heat dissipation stored in the frame, and a micro-airflow environment can be formed in the living area. This paper aimed to verify thermal comfort and proper operation. Subjects were given simulated work of low to high metabolic rate, and were asked to report the thermal sensation and comfort in a micro-airflow environment. It was confirmed that comfort could be maintained even at a temperature higher than the general air-conditioning temperature, and an appropriate operating method according to the metabolic rate was elucidated.publishedVersio
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