•The study of urban energy systems can ensure sustainable development.•Rather than separate cities by function, we must consider them as a single system.•A complementary way to study urban metabolism ...is including energy services.•Urban metabolism embraces the importance of interdisciplinary work.
The way we make sense of urban areas stands at a critical point. To reduce energy use in cities, we need to manage the way energy flows into, through and out the city. This paper starts with an overview on energy use at different levels of aggregation which allows us to outline emerging issues on urban metabolism for further research regarding urban energy systems. The research agenda focuses on five aspects: energy services, drivers for energy services, waste, data and dynamic modelling and governance. We give indications regarding the direction we think we should aspire to follow. The variety of themes within urban energy systems demands a coordinated and multidisciplinary research effort to improve our understanding of how the research of urban metabolism can contribute to achieve sustainable development.
Decomposition analysis is used to assess the progress in decoupling Italian economic growth from CO2 emissions. Using the method developed by Sun JW. Accounting for energy use in China, 1980–94. ...Energy 1998;23:835-49, the main factors that influence the changes in energy-related CO2 emissions are analysed. The study refers to the period 1998–2006, split into two time intervals (1998–2002 and 2002–2006) and considers four explanatory factors: CO2 intensity, energy intensity, structural changes and economic activity. The importance of sectoral dimension is taken into account by dividing the Italian economy into five main sectors: the agricultural; the industrial; the electricity and heat production, water and gas; the transport and the services sectors. An industrial sub-sector decomposition analysis is also performed by considering six industrial branches. It is found that, during the period considered, the Italian economy did not perform absolute decoupling in terms of energy consumption and carbon dioxide emissions and that economic growth and energy intensity are the largest contributors to CO2 emissions increase.
► Decomposition analysis is used to analyse the main factors that influenced the changes in energy-related CO2emissions. ► Economic growth and energy intensity are the main factors affecting CO2emissions change. ► From 1998 to 2006, Italian economy not performed an absolute decoupling in terms of energy consumption and CO2 emissions.
The indirect energy cost shares around one-tenth of the total energy expenditure throughout the typical power plant’s lifetime. Display omitted
•An embodied energy accounting for a typical coal-fired ...power system is undertaken.•An inventory of life cycle energy inputs for the power plant is established.•Full consideration is given to energy embodied in materials, equipment and services.•The indirect energy cost shares around one-tenth of the total.•This work could be a reference for holistic evaluation of power systems worldwide.
Coal-based power generation accounts for over two fifths of global electricity supply and is supposed to be continuing its leading role in the coming decades. However, an integrated embodied energy accounting for typical coal-fired power system seems to be in its vacancy. To help erect a benchmark for energy analysis of electricity production, this study has for the first time established a complete inventory of energy inputs in the life cycle of a typical coal-fired power plant. Distinguished from previous works, with the support of ecological input–output database, this paper gives full consideration to the energy embodied in materials, equipment and services that have been traditionally neglected. The indirect energy cost is illustrated to be a non-negligible component, sharing around one-tenth of the total. This work could be a reference example for holistic energy evaluation of power generation systems worldwide. In current context of energy conservation and emissions abatement, it is of significant importance as the retrofitting of power generation systems may initiate large amounts of indirect energy cost. Besides, by calculating the nonrenewability indicator for the typical coal-fired power system, the energy saving potentials of several renewable alternatives are enunciated in this work. It may provide essential implications for policy makers in renewable deployment.
IntroductionGrape (Vitis vinifera L.) is one of the most important agricultural products in the Mediterranean. Today, grapes are grown in a large area of the world's gardens. The world production of ...grapes was about 77.8 million tons in 2018, of which 1.3 million tons were converted into raisins. According to the latest data of FAO, Iran has an annual production of 24.45 million tons of grapes in an area of 213 thousand hectares, accounting for 3% of the world's grape production. The average yield per hectare of vineyard is reported to be 15.5 tons. The purpose of this study is to determine hot spots in terms of energy and cost in the production of Malayer grapes with the approach of material and energy flow costing (MEFCA). The primary focus of material and energy flow cost accounting is on waste (waste of energy, materials and potential human capacity). Materials and MethodsMaterial flow cost accounting was introduced in the late 1990s in Augsburg, Germany as a tool for green productivity management. This is known as a tool to increase productivity by reducing the use of materials, energy and human resources. Unlike life cycle assessment, which only weighs the environmental impacts of production and does not provide a solution for simultaneously reducing environmental impacts and increasing economic profit, material flow costing is recognized as an efficient tool for managing resources, wastes, and environmental impacts, and has covered the shortcomings of life cycle assessment. Material flow cost accounting helps to discover hidden costs and waste by objectifying the flow of materials in the production process. Based on ISO 14051 material flow analysis occurs in quantitative centers (QCs). In general, each quantitative center divides the production process into several parts. The basis of material flow and energy costing is material flow balance. This means that the inputs must be the same as the outputs. Based on this balance, positive inputs (i.e. consumable inputs) and positive outputs (i.e. product performance) and negative outputs (i.e. wastes and emissions during production) should be equal. The primary focus of material and energy flow costing is on waste (e.g. waste of energy, materials and potential human capacity). Allocation of costs to positive and negative products in each quantitative center is done in the following way:- Material cost (including raw and industrial materials used in the production process)- Energy costs (including electricity or buying diesel fuel)- System costs (including labor costs, transportation costs and system maintenance)- Waste cost (including waste management costs)The system boundary included the background processes that the farmer was directly involved in using and managing. Grape data was collected in the crop year of 2020-2021 from Malayer vineyards. Results and DiscussionBased on the results of the study, the average energy input including renewable, non-renewable, direct and indirect energy for grape production was 42234 MJ ha-1. The negative energy resulting from the wastage of chemical fertilizers, grapes, irrigation water and pesticides was 28650 MJ ha-1. The total positive output energy was calculated as 296180 MJ ha-1. Nitrogen fertilizer with 27% and animal manure with 19% had the largest share in input energy for grape production. In terms of negative energy, grape waste accounted for the largest share with 82% and the Irrigation water wastage was the next with 16%. Energy indices including energy efficiency (6.33), energy productivity (0.59) kgMJ-1), energy intensity (1.68 MJkg-1) and net energy gain (1225295 MJha-1) were calculated for grape production. The cost of grape production per hectare was $2,779. The highest input costs were related to labor and irrigation water, which cost the farmer 1644 and 680 dollars per hectare, respectively. The calculated negative production in grape production was equal to 2560 dollars per hectare. The main negative production in grape was related to wastage of grapes and irrigation water, which brought hidden costs of 2108 and 442 dollars to the farmer, respectively. The economic indicators of gross income (13954 $ha-1) and cost-benefit ratio (4.5) were calculated. ConclusionTransitioning from flood irrigation to drip irrigation is anticipated to enhance irrigation efficiency by 50%, resulting in an incremental addition of $221 to the farmer's income while concurrently reducing labor costs. Additionally, emphasizing training for workers can prove pivotal in minimizing grape yield wastage within the region.
Increasing energy costs and environmental concerns have motivated engineering microbes for the production of "second generation" biofuels that have better properties than ethanol.
Saccharomyces ...cerevisiae was engineered with an n-butanol biosynthetic pathway, in which isozymes from a number of different organisms (S. cerevisiae, Escherichia coli, Clostridium beijerinckii, and Ralstonia eutropha) were substituted for the Clostridial enzymes and their effect on n-butanol production was compared. By choosing the appropriate isozymes, we were able to improve production of n-butanol ten-fold to 2.5 mg/L. The most productive strains harbored the C. beijerinckii 3-hydroxybutyryl-CoA dehydrogenase, which uses NADH as a co-factor, rather than the R. eutropha isozyme, which uses NADPH, and the acetoacetyl-CoA transferase from S. cerevisiae or E. coli rather than that from R. eutropha. Surprisingly, expression of the genes encoding the butyryl-CoA dehydrogenase from C. beijerinckii (bcd and etfAB) did not improve butanol production significantly as previously reported in E. coli. Using metabolite analysis, we were able to determine which steps in the n-butanol biosynthetic pathway were the most problematic and ripe for future improvement.
An energy analysis comparing three different soil management systems was carried out in Southern Italy using data collected in a five-year field experiment, with the aim of identifying the most ...energy efficient system. On average, because of a little more energy is demanded (13.3 GJ ha−1) and a higher grain yield is obtained (2.20 t ha−1) in the Intensive practice than in the other two, the total Energy Input required to produce 1 kg durum wheat was higher in the No tillage-based system (11.05 MJ kg−1) than in the Intensive (6.80 MJ kg−1) and the Minimum one (6.78 MJ kg−1). The highest contribution to Energy Input derived from nitrogen fertiliser followed by diesel fuel. In this regard, No-tillage allowed for reduction of diesel energy consumption by about 70% and 60% compared with Intensive tillage and Minimum tillage, respectively. The Minimum tillage practice showed the best energy performance, because it determined the following results on an average base: the highest energy ratio (4.69) and the highest energy profitability (3.69); the lowest energy intensity (5.86 MJ kg−1). Therefore, under the environmental conditions in which the experimens were carried out, MT may be considered as the practice exhibiting the best energy performance and representing the viable trade-off between IT and NT.
•Durum wheat soil management systems have been tested in Sicily during five-years.•The study identifies the most energy efficient tillage system for durum wheat.•Low rainfall conditions produced higher yields in No tillage.•Minimum tillage have shown the lowest total energy input and a high energy output.
We present a new model-independent strategy for testing the Friedmann-Lemaître-Robertson-Walker (FLRW) metric and constraining cosmic curvature, based on future time-delay measurements of strongly ...lensed quasar-elliptical galaxy systems from the Large Synoptic Survey Telescope and supernova observations from the Dark Energy Survey. The test only relies on geometric optics. It is independent of the energy contents of the universe and the validity of the Einstein equation on cosmological scales. The study comprises two levels: testing the FLRW metric through the distance sum rule (DSR) and determining/constraining cosmic curvature. We propose an effective and efficient (redshift) evolution model for performing the former test, which allows us to concretely specify the violation criterion for the FLRW DSR. If the FLRW metric is consistent with the observations, then on the second level the cosmic curvature parameter will be constrained to ∼0.057 or ∼0.041 (1 ), depending on the availability of high-redshift supernovae, which is much more stringent than current model-independent techniques. We also show that the bias in the time-delay method might be well controlled, leading to robust results. The proposed method is a new independent tool for both testing the fundamental assumptions of homogeneity and isotropy in cosmology and for determining cosmic curvature. It is complementary to cosmic microwave background plus baryon acoustic oscillation analyses, which normally assume a cosmological model with dark energy domination in the late-time universe.
ABSTRACT Radio-mode active galactic nucleus (AGN) feedback plays a key role in the evolution of galaxy groups and clusters. Its physical origin lies in the kiloparsec-scale interaction of AGN jets ...with the intracluster medium. Large-scale jet simulations often initiate light internally supersonic jets with density contrast 0.01 < < 1. Here we argue for the first time for the importance of very light ( < 0.01) internally subsonic jets. We investigated the shapes of young X-ray cavities produced in a suite of hydrodynamic simulations, and found that bottom-wide cavities are always produced by internally subsonic jets, while internally supersonic jets inflate cylindrical, center-wide, or top-wide cavities. We found examples of real cavities with shapes analogous to those inflated in our simulations by internally subsonic and internally supersonic jets, suggesting a dichotomy of AGN jets according to their internal Mach numbers. We further studied the long-term cavity evolution, and found that old cavities resulted from light jets spread along the jet direction, while those produced by very light jets are significantly elongated along the perpendicular direction. The northwestern ghost cavity in Perseus is pancake shaped, providing tentative evidence for the existence of very light jets. Our simulations show that very light internally subsonic jets decelerate faster and rise much slower in the intracluster medium than light internally supersonic jets, possibly depositing a larger fraction of jet energy to cluster cores and alleviating the problem of low coupling efficiencies found previously. The internal Mach number points to the jet's energy content, and internally subsonic jets are energetically dominated by non-kinetic energy, such as thermal energy, cosmic rays, or magnetic fields.
Propagating coronal mass ejections (CMEs) are often accompanied by burst signatures in radio spectrogram data. We present Nancay Radioheliograph observations of a moving source of broadband radio ...emission, commonly referred to as a type IV radio burst (type IVM), which occurred in association with a CME on the 14th of August 2010. The event was well observed at extreme ultraviolet (EUV) wavelengths by SDO/AIA and PROBA2/SWAP, and by the STEREO SECCHI and SOHO LASCO white light (WL) coronagraphs. The EUV and WL observations show the type IVM source to be cospatial with the CME core. The observed spectra is well fitted by a power law with a negative slope, which is consistent with optically thin gyrosynchrotron emission. The spectrum shows no turn over at the lowest Nancay frequencies. By comparing simulated gyrosynchrotron spectra with Nancay Radioheliograph observations, and performing a rigorous parameter search we are able to constrain several key parameters of the underlying plasma. Simulated spectra found to fit the data suggest a nonthermal electron distribution with a low energy cutoff of several tens to 100 keV, with a nonthermal electron density in the range 10 super(0)-10 super(2) cm super(-3), in a magnetic field of a few Gauss. The nonthermal energy content of the source is found to contain 0.001%-0.1% of the sources thermal energy content. Furthermore, the energy loss timescale for this distribution equates to several hours, suggesting that the electrons could be accelerated during the CME initiation or early propagation phase and become trapped in the magnetic structure of the CME core without the need to be replenished.
This article traces Howard Scott's technocracy movement in the United States from the 1930s onwards, attempting to rearticulate it as a moment in interwar non-conformism. Conceived in America's ...culture of material affluence, the technocracy movement was intellectually based on two fin-de-siècle undercurrents: the scientific management movement and Veblen's institutional economics. The technocracy movement appropriated and developed their ideas of efficiency and waste, attempting to negotiate a space between industrial capitalism and socialism by offering new ideas of managing society based on maximizing productive efficiency and minimizing waste. While its political disorganization and Scott's spotty past turned brief success into ultimate failure, the speed and intensity of the popular following for technocracy testifies to the broad appeal of 1930s non-conformism. Further, responding to looming unemployment in the pursuit of efficiency through mechanization, the technocracy presented, if accidentally, an ecological vision manifest in the idea of energy certificates. Yet, the fundamentally productivist premise of the movement ultimately marred its substantive development and made the movement fragmented and functionally appropriated.
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