70 research outputs found

    The Leverage of Demographic Dynamics on Carbon Dioxide Emissions: Does Age Structure Matter?

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    This article provides a methodological contribution to the study of the effect of changes in population age structure on carbon dioxide (CO2) emissions. First, I propose a generalization of the IPAT equation to a multisector economy with an age-structured population and discuss the insights that can be obtained in the context of stable population theory. Second, I suggest a statistical model of household consumption as a function of household size and age structure to quantitatively evaluate the extent of economies of scale in consumption of energy-intensive goods, and to estimate age-specific profiles of consumption of energy-intensive goods and of CO2 emissions. Third, I offer an illustration of the methodologies using data for the United States. The analysis shows that per-capita CO2 emissions increase with age until the individual is in his or her 60s, and then emissions tend to decrease. Holding everything else constant, the expected change in U.S. population age distribution during the next four decades is likely to have a small, but noticeable, positive impact on CO2 emissions

    Autothermal reforming of palm empty fruit bunch bio-oil: thermodynamic modelling

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    This work focuses on thermodynamic analysis of the autothermal reforming of palm empty fruit bunch (PEFB) bio-oil for the production of hydrogen and syngas. PEFB bio-oil composition was simulated using bio-oil surrogates generated from a mixture of acetic acid, phenol, levoglucosan, palmitic acid and furfural. A sensitivity analysis revealed that the hydrogen and syngas yields were not sensitive to actual bio-oil composition, but were determined by a good match of molar elemental composition between real bio-oil and surrogate mixture. The maximum hydrogen yield obtained under constant reaction enthalpy and pressure was about 12 wt% at S/C = 1 and increased to about 18 wt% at S/C = 4; both yields occurring at equivalence ratio Φ of 0.31. The possibility of generating syngas with varying H2 and CO content using autothermal reforming was analysed and application of this process to fuel cells and Fischer-Tropsch synthesis is discussed. Using a novel simple modelling methodology, reaction mechanisms were proposed which were able to account for equilibrium product distribution. It was evident that different combinations of reactions could be used to obtain the same equilibrium product concentrations. One proposed reaction mechanism, referred to as the ‘partial oxidation based mechanism’ involved the partial oxidation reaction of the bio-oil to produce hydrogen, with the extent of steam reforming and water gas shift reactions varying depending on the amount of oxygen used. Another proposed mechanism, referred to as the ‘complete oxidation based mechanism’ was represented by thermal decomposition of about 30% of bio-oil and hydrogen production obtained by decomposition, steam reforming, water gas shift and carbon gasification reactions. The importance of these mechanisms in assisting in the eventual choice of catalyst to be used in a real ATR of PEFB bio-oil process was discussed

    A three-step numerical approximant based on block hybrid backward differentiation formula for stiff system of ordinary differential equation

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    We present results of an analysis of the reaction γγωϱγγ→ωϱ in the two-photon process e+eϵ+e2π+2ππ0e^+e^−→ϵ^+e^−2π^+2π^−π^0 in the untagged mode. The cross section is largely compatible with previous determinations; however, we do not confirm the enhancement claimed at 1.9 GeV. All observed ω's are accompanied by ϱ's in the recoiling ππ spectrum. An angular correlation analysis shows that the data is not dominated by a single spin-parity state, thus establishing severe constraints on qqqqqqqq models which predict JP=2+JP= 2^+

    Алгоритм сжатия на основе вычисления скорости изменения ультразвукового сигнала

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    The intermittency structure of multihadronic e+e- annihilation is analyzed by evaluating the factorial moments F2-F5 in three-dimensional Lorentz invariant phase space as a function of the resolution scale. We interpret our data in the language of fractal objects. It turns out that the fractal dimension depends on the resolution scale in a way that can be attributed to geometrical resolution effects and dynamical effects, such as the pi-O Dalitz decay. The LUND 7.2 hadronization model provides an excellent description of the data. There is no indication of unexplained multiplicity fluctuations in small phase space regions

    Разработка модульного стенда физического подобия для изучения гидротехнических систем

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    В рамках данной работы проведен обзор и анализ образовательных стендов, сформулирована концепция модульного стенда физического подобия, разработаны функциональные схемы двух модулей, в соответствии с которыми подобраны основные элементы. Для первого модуля предоставлены принципиальная схема и демонстрационный алгоритм работы.In this work, a review and analysis of educational booths, formulated the concept of modular stand physical similarity, developed functional diagrams of the two modules, in accordance with which the selected basic elements. For the first module, a schematic diagram and a demonstration algorithm are provided

    Накопление газообразных продуктов деления и соединений в микрокапсулированном топливе в сверхдлинных кампаниях

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    The production of b and c quarks in e+ee^+e^− annihilation has been studied with the CELLO detector in the range from 35 GeV up to the highest PETRA energies. The heavy quarks have been tagged by their semileptonic decays. The charge asymmetries for b quarks at 35 and 43 GeV have been found to be Ab=(22.2±8.1)A^b=−(22.2±8.1)%% and %A^b=−(49.1±16.5)%, respectively, using a method incorporating jet variables and their correlations for the separation of the heavy quarks from the back ground of the lighter quarks. For c quarks we obtain Ac=(12.9±8.8)A^c=−(12.9±8.8)% and Ac=+(7.7±14.0)A^c=+(7.7±14.0)%, respectively. The axial vector coupling constants of the heavy quarks c and b are found to be ac=+(0.29±0.46)a^c=+(0.29±0.46) and ab=(1.15±0.41)a^b=−(1.15±0.41) taking B0(ˉB0)B0(ˉB0)B^0 \bar(B^0) B^0\bar(B^0) mixing into account. The results are in agreement with the expectations from the standard model

    Simulating the integration of photovoltaic technology on the modern infantry soldier using modelling andsimulation:scenarios and guidelines

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    The operational range and manoeuvrability of the modern infantry soldier is restricted by the overall load and bulk of equipment ranging from 50 to 75 kg. Today’s soldiers rely heavily on batteries to meet their power requirements, which make up 25% of the overall load. This results in a significant increase on soldier’s physical stress and cognitive burden. Recent developments in renewable energy, and more particularly the evolution of very thin and flexible wearable photovoltaic devices, provide promising solutions for the application of such technologies on the infantry soldier. However, since these flexible substrate devices are still under development or produced at a very small scale, their application and use has to be simulated prior to integrating to the infantry soldier. Such simulations need to take into account the specific requirements and different fields of operation of the infantry soldier, in the context of weather, date and time, global location and for different military mission environments. This paper presents a number of simulations performed for a wide range of scenarios in the context of the Solar Soldier project. It discusses the key results, offering a set of guidelines for the positioning and integration of such renewable energy technology on the modern infantry soldier. Moreover, this paper suggests future improvements on the methodology and optimisation of the procedures
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