1,721,362 research outputs found
Controls and inspections for the durability of r.c. structures
No full textDurability of reinforced concrete structures is a basic requirement in order to maintain the safety levels during the designed service life. To guarantee this requirement it is essential that controls and inspections, both in the design and construction phases and during the service life of the structures, are carried out. These can be used to analyze different design solutions, the real conditions of the structure and changes in performance over time. Thus the sustainability of reinforced concrete structures can be enhanced, by choosing in the design phase solutions that reduce the environmental impact and carrying out preventive action, reducing costs, resource consumption and emissions. As an example, the data of inspections, controls and monitoring of the reinforced concrete structures of the G. Meazza stadium in Milano are reported. These are used for the evaluation of the conservation conditions of the structure, the effectiveness of the repairs carried out over time and for the maintenance planning
Decomposing growth in a multiregional I-O framework
No full textSince the pioneering work of Wassilly Leontief, a remarkable amount of theoretical and empirical work has continuously supported Input-Output modelling. In particular, the peculiar structure of dynamic input-output (I-O) model have originated, in numerous fields ranging from mathematical economics to system theory, an abundance of contributes. This paper deals with the computational problem of managing regional growth within a dynamic multiregional input-output model. Starting from the basic matrices of technological capital and trade coefficients, the regional components associated to a given group of regions are appropriately recognised and separated. A numerical example, based on the Italian case, is also discussed
The influence of hydrophobic surface coatings on carbonation induced corrosion in reinforced concrete structures|Effetto di un rivestimento idrorepellente sulla corrosione da carbonatazione in strutture in calcestruzzo armato
No full textRebar corrosion is the main cause of deterioration in reinforced concrete structures and leading not only to problems regarding the user’s safety but also to high costs for necessary repairs. Carbonation of concrete in contact with reinforcements leads to a uniform consumption of the rebars cross section, the formation of expansive corrosion products and thus cracking and spalling of the concrete cover. Hydrophobic pore lining treatments can be an interesting method to control the propagation of rebar corrosion in carbonated concrete and, thus, to prolongate the service life of the structures. In this paper, the effect of a hydrophobic coating on initiation and propagation of carbonation-induced corrosion was analysed
Effects of a hydrophobic treatment on corrosion propagation in carbonated reinforced concrete structures
No full textOn reinforcement in carbonated concrete, corrosion can propagate and lead, even after few years, to cracking and spalling of the concrete cover. Thus, costly repairs both economically and considering the impact on the environment are needed. The use of a hydrophobic treatment allows to control the propagation of corrosion in carbonated concrete, delaying concrete cracking and spalling and removing only cracked concrete. This paper reports the results of experimental tests carried out to study a new type of hydrophobic treatment. The capability of this coating to penetrate through the concrete, not to cause corrosion problems to the reinforcements still in a passive condition (in alkaline concrete) and to control the propagation of reinforcements corrosion in carbonated concrete was analysed. The effectiveness of this coating under different exposure conditions was assessed
Last mile distribution using cargo bikes: a simulation study in Padova
Full text linkThe recent growth of e-Commerce has induced an increasing freight demand, which could lead to negative externalities, in particular in urban areas. To foster sustainable development of cities and increase their livability, many local authorities are implementing urban vehicle access regulations, such as low -emission zones, banning the circulation of polluting vehicles. These measures prompted the adoption of new sustainable freight transport solutions for last mile deliveries, such as cargo bikes. The aim of this paper is to describe the study for the implementation of such a system. The procedure was tested (1) to define the location of a transshipment facility where parcels are moved from vans to cargo bikes, (2) to estimate the environmental and economic sustainability of the system, and (3) to quantify the effects of uncertainty in the final results. The framework was applied to the city center of Padova (Italy), where two sets of delivery system were considered: the first with traditional vans starting from an existing urban consolidation center and the second with manual and electric cargo bikes starting from a micro-depot. In particular, demand of home deliveries was estimated for a typical weekday; routes of freight transport means were defined by an optimization procedure; these data were used as input to a Discrete Event Simulation model. A sensitivity analysis was carried out modelling the potential uncertainty associated with load/unload times and travel speed of means, due to traffic congestion. Several scenarios were tested considering three locations as potential transshipment points. Outcomes of the simulations were used to estimate key performance indicators, evaluating the environmental and economic effects of the two delivery schemes. Results highlighted the potentiality of cargo bikes as a sustainable delivery system, and the impacts of uncertainty on the ranking of alternative options (i.e. micro-hubs)
A social analysis of the olive oil sector: The role of family business
Full text linkExtra-virgin olive oil (EVOO) is one of the most popular products in Mediterranean diet. Spain produces about 52% of olive oil with the presence of larger firms; Italy follows with a share of 9% and a production structure characterized instead by small family businesses. A social analysis, based on a multiple-questionnaire, has analyzed the perspectives of 500 consumers conferring their olives to a family-owned olive oil mills (OOMs). This work aims to assess the role of family business evaluating the opportunities associated with the development of circular economy (CE) models. Results show that Italian consumers' preferences give attention to the use of natural resource and the olive oil is perceived as a natural product. In addition, family owned-OOMs provide a great sense of trust and the relevant role of family within the entire life cycle of olive oil is demonstrated. OOMs that work for residential market are strongly preferred to industrial ones being able to manage single lots of olives belonging to the same customers' land. The recovery of some by-products represents an opportunity for OOMs and policy support is required to favor the needed generational change, whose absence is perceived as a serious obstacle to the future development of the sector along circularity principles
Solar collective self-consumption. Economic analysis of a policy mix
No full textSolar photovoltaic (PV) systems can play a key role in ecosystems by satisfying the energy needs of people and businesses, helping countries become energy independent and propelling nations towards a climate-neutral future. Within this context, collective self-consumption (CSC) represents a new challenge, anchored in a new conception of the prosumer. The present work aims at calculating the economic profitability of PV systems with respect to both household and non-household self-consumers. The methodology is based on the calculation of net present value (NPV), with break-even point (BEP) analysis applied to the percentage of self-consumed energy. As economic viability is dependent on the specific policy tool(s) available, the analysis is applied to the Italian context, considering both a tax deduction of 110% over 5 years and a CSC subsidy of 100 €/MWh. The findings demonstrate economic profitability in multiple scenarios, strongly linked to the percentage of self-consumed energy. The mix of policy tools significantly influences the results and generates BEPs in the range of 8–13% (calculated in terms of the share of self-consumed energy) and NPVs ranging from 1035 to 3178 €/kW for 30–60% self-consumption. Profit distribution scenarios among renewables self-consumers (RSCs) and policy recommendations are provided to foster RSC development, and thereby make residents responsible for their country's energy transition
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Environmental protection, economic efficiency and intermodal competition in freight transport
No full textThe awareness of the consequences of a further rise in transport for the environment has not only been a matter of concern for scientific researchers but also for planners and policy-makers. In fact, the environment is now an ever present factor in the new political agenda and issues of excessive traffic congestion and global atmospheric pollution are increasingly attracting administrators' attention. One of the most important scenarios proposed for the protection of the environment, taking into account the adverse effects of traffic, is the redistribution of freight transport demand. In this paper the Italian situation has been tested, evidencing productive sectors and regions really benefiting from a more effective redistribution of trade flows among existing links on the freight network. This pattern is estimated by evaluating substitution elasticities before and after the introduction of a pollution tax. Numerical simulations, in terms of reduction of pollution emissions and transportation costs, are also provided. Copyright © 1996 Elsevier Science Ltd
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