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Corrigendum. Maars to calderas: end-members on a spectrum of explosive volcanic depressions
Full text linkA corrigendum on
Maars to calderas: end-members on a spectrum of explosive volcanic depressions
by Palladino, D. M., Valentine, G. A., Sottili, G., and Taddeucci, J. (2015). Front. Earth Sci. 3:36.
doi: 10.3389/feart.2015.00036
Reason for Corrigendum:
In the original article (Palladino et al., 2015), there was an error in Figure 1. The vertical axis
of the qualitative plot reported erroneously “ratio of juvenile to lithic materials in deposits outside
of depression”. The correct wording is as follows: “ratio of juvenile to total (i.e., juvenile+lithic)
materials in deposits outside of depression”. In fact, as it was reported correctly in the text, the
amount of juvenilematerial (i.e., scoria or pumice) deposited ouside the different types of explosive
volcanic depressions increases from zero (i.e., no juvenile, all lithic products), as is the case of
hydrothermal (phreatic) explosion craters, to become largely dominant over the lithic component
in the case of ash flow deposits associated with large overpressure collapse calderas. The corrected Figure 1 appears below. The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way
Greening Umbria’s Future: Investigation of the Retrofit Measures’ Potential to Achieve Energy Goals by 2030 in the Umbria Region
Full text linkThe new European targets of achieving net zero emissions by 2050 have spurred Italy to aim for a 30% reduction in emissions by 2030, compared with 2005 levels. This goal will be achieved through the promotion of renewable energy sources and energy savings in the residential sector, which remains one of the main sectors accountable for total energy consumption, mainly for heating. This study aims at investigating the potential of some retrofit measures implemented in the Umbria Region, chosen as a case study, to reach the goal by 2030. Using parametric energy simulations with the standard calculation method and artificial neural networks (ANN), the energy consumption of Umbria’s building stock and potential CO2 reductions were assessed. Results showed that with current energy policies, a reduction of 28% could be achieved, which is below the goal by 2030, while ANN integration within energy strategies could allow reaching it as early as 2025 or 2029, depending on the restriction set to the ANN and the extent of current energy policies. This study confirmed the potential benefits of using advanced technology in achieving national environmental goals, highlighting that they could be essential tools to be integrated into energy policies to accelerate progress towards ambitious climate goals
Energy performance gap of the Italian residential building stock: Parametric energy simulations for theoretical deviation assessment from standard conditions
Full text linkEnergy Performance Gap (EPG) is a crucial issue in the building sector that can lead to an overestimation of the national energy policies. It is the difference between the calculated energy consumption and actual energy use, and it is relevant mainly for space heating. As EPG quantification or correction methods could lead to more realistic energy policies, EPG has become a focus of many studies and research. In this framework, this study aims to quantify the theoretical deviation of EPG, i.e., concerning to the standard conditions, for the Italian residential building stock by performing parametric energy simulations of thousands of representative reference buildings. After a comprehensive thermophysical characterization of the national building stock, parametric simulations were carried out by varying the main standard conditions set in the Energy Performance Certificate (EPC) calculation. This approach allowed the quantification of EPG according to the climatic zone, building type, usage profile, and thermal insulation level of buildings, while also analysing the influence of these parameters on the EPG and checking for prebound or rebound effects (i.e. when standard consumption is greater or smaller than actual one). The study identified a range of EPG variability for both prebound (0% to +80%) and rebound (−30% to 0%) effects and quantified an average EPG between −3 and +16 kWh per heating degree day of the selected location as a function of the usage profile. This work represents the first attempt to calculate the EPG of the Italian residential building stock and it could lead to the correction of the national energy policies implemented in the building sector
Energy Planning of Renewable Energy Sources in an Italian Context: Energy Forecasting Analysis of Photovoltaic Systems in the Residential Sector
Full text linkSolar photovoltaic systems will play a key role in the country’s energy mix thanks to their ability to meet increasing energy needs while reducing greenhouse gas emissions. Despite the potential of solar photovoltaic energy, several criticalities remain, such as the intermittent nature and the need for significant land use for its implementation. In this regard, this work aimed at evaluating the photovoltaic potentiality in a national context by 2030 and 2050, considering only installations on the roof surfaces of existing buildings, i.e., without consuming additional land. This study has allowed the answering of three key points: (i) the roof surface could represent a valuable and alternative solution for new installations, since it could amount to around 450 km2, (ii) the national target cannot be reached by only using installations on existing buildings, although some regions could get close to the target by 2050, and (iii) long-term energy incentives should be implemented branching out to each national region, considering their photovoltaic potential. Finally, a regional potential index was also defined, capable of evaluating the photovoltaic potential in each region, helping policymakers to adopt the most suitable energy strategies
On the mobility of pyroclastic currents in light of deposit thickness and clast size trends
No full textPyroclastic currents (PCs) represent the most hazardous manifestations of explosive volcanic activity. The evaluation of their mobility, as related to the eruptive source parameters and the interactions with the surroundings along their path, is crucial for hazard assessment at active volcanoes in order to define the areas exposed to their impacts. Here we report on two case studies from the Latera Volcanic Complex (Vulsini Volcanic District, central Italy) that may approach the two end-members of the classical spectrum of PC dynamics in terms of particle concentration and dominant flow regime (i.e., dilute, turbulent vs. concentrated, laminar PCs). For the two examples, we document specific (and contrasting) variation trends of deposit thickness and maximum lithic and pumice clast sizes with distance from vent, which provide a further characterization in terms of forced vs. inertial flow behavior. In the first case, thickness and maximum lithic and pumice sizes show a mild, linear decrease with distance, implying a sort of balance between forced and inertial regimes. Flow pressure and mass progressively drop via deposition, along with flow competence. For given source conditions (i.e., mass eruption rate, fountaining height, erupting mixture, etc.) and slope angle of topography, the PC runout depends primarily on the waning density contrast between the flow and the surrounding atmosphere (density current), ending with the loft of the current. The second case, representative of moderate- to large-volume, dense PCs derived by continuous feeding with high mass discharge rate (i.e., from collapsing Plinian columns or caldera-forming events), shows an increase of deposit thickness with distance, which is accompanied by opposite lithic and pumice clast size-distance trends (i.e., decreasing lithic sizes and increasing pumice sizes downcurrent), compatible with high particle concentration and forced, non-turbulent, granular flow regime. By analogy with the mobility of dry debris flows, we suggest that the sliding component of transport, which prevails in proximal to intermediate settings, may account for the prevailing tendency of the PC to transport than to deposit, which leaves behind relatively thin sheets with coarse lithics, while the dominant spreading component downcurrent would result in increasing accumulation and the stacking of coarse pumice-rich flow lobes in more distal settings. The spreading component of transport would become more and more important with increasing material supply at PC source, resulting in additional runout. These findings cast new light on the first-order controlling factors of flow mobility for the two PC end-members, laying the groundwork for determining the most relevant PC hazard parameters, i.e. the maximum runout and the flow properties upon impact (dynamic pressure, burial potential, temperature)
Source- vs topographic-forcing in pyroclastic currents. the case of the Orvieto-Bagnoregio Ignimbrite, Vulsini, central Italy
Full text linkThe main pyroclastic flow unit of the Orvieto-Bagnoregio Ignimbrite (Vulsini, central Italy) provides a striking example of increasing thickness with distance from the vent, accompanied by opposite size-distance trends for lithic and juvenile clasts. Lithic clasts show normal lateral grading, while dense (1120-1400 kg/m3) scoria clasts show inverse lateral grading. The latter trends are attributed to the opposite density contrast with respect to the flow medium of gas and fine particles and put a constraint to the minimum density of the transporting flow. Thus, the study example approaches the high concentration, non-turbulent end-member of pyroclastic currents. By applying the topological aspect ratio approach, we infer a forced behavior of the parent flow in proximal to intermediate settings, due to sustained feeding with high mass discharge rate at source. In distal settings, the source-forced regime was enhanced by topographic forcing due to channeling along radial topographic lows, thus resulting in increasing bulk density and runout of the current. By analogy with the mobility of dry debris flows, the sliding component of transport prevailed from proximal to intermediate settings, accounting for the prevailing tendency of the pyroclastic current to transport than to deposit, thus forming a relatively thin deposit with normal lateral grading of lithics. The spreading component dominated toward the distal settings, resulting in increasing pyroclast accumulation (up to tens of meters of thickness) and delayed deposition of coarsest scoria clasts as far as the final runout
Energy and Economic Savings Assessment of Energy Refurbishment Actions in Italian Residential Buildings: Comparison between Asset and Tailored Calculation
Full text linkResidential buildings have become one of the leading sectors in the energy refurbishment process towards the clean energy transition. Energy Performance Certificates (EPCs), based on the asset rating calculation method, are often used to quantify the energy performance in standard conditions before and after renovation, but their energy outcomes can significantly differ from the actual energy consumption and savings. More consistent results can be obtained by adopting a “tailored” approach, capable of considering more the actual building operation conditions and users’ behaviour. In this framework, the study evaluates the heating energy needs of Italian representative multi-family houses in all the climatic zones and five retrofitting scenarios with both asset and tailored ratings. Finally, a cost–benefit analysis, based on energy savings and interventions costs, is also carried out to assess the affordability of the refurbishment actions depending on the adopted calculation methods. The analysis of retrofitting scenarios highlighted that asset energy outcomes are generally slightly greater than the tailored ones (differences of around 3–13% on average), but the affordability of the chosen energy efficiency measures is significantly overrated. It could underline the need to adopt the tailored approach for more accurate energy savings assessment and economic evaluation
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