Analysis of different typologies of natural insulation materials with economic and performances evaluation of the same in building

Considering the significant impact that the residential sector has on energy consumption, it is particularly important to implement policies aimed at improving energy efficiency in buildings for saving primary energy, and also to spread the concept of sustainable development through the use of appropriate technology and proper project criteria both for new constructions and for the rehabilitation of existing ones. It is in this context and in an attempt to reduce as much as possible the consumption of resources that fits the possibility of utilizing "natural" materials for the insulation of buildings. In this work they have been analyzed the natural insulation materials present on the Italian building market, where for "natural" it is meant the ones that are derived from renewable materials, which emit no pollutants and that are recyclable or biodegradable. Then it has been created a database which highlights the physical and thermohygrometrical characteristics (density, conductivity, specific heat, vapor permeability, etc.), as well as the possible applications (ceiling, wall, roof). Then it has been carried out a performing and economic comparison related to the replacement of the traditional insulation of a residential building located in Perugia (Central Italy) with the majority of the insulating materials identified in relation to its type of use. The synthetic insulating materials have been replaced in order to reach, for the analysed building, the same thermal performances obtained with the application of traditional insulators. From the analysis of dynamic thermal parameters has been deduced that the building envelope insulated with natural products has better thermal summer performances compared to the same insulated with traditional materials such as XPS, with the same thermal winter performances. This improvement is mainly due to the high value of the specific heat characteristic of the natural insulators. Finally, it has been carried out an economic comparison between the two types of insulation from which it has been possible to deduce that the utilize of natural insulation products have meant an increase in the costs which is widely variable depending on the type of natural insulator used

Current and Future Research Trends in Substrate Integrated Waveguide Technology

Substrate Integrated Waveguide (SIW) technology is the most promising candidate for the implementation of millimeter-wave (mm-wave) integrated circuits and systems for the next decade. Based on planar dielectric substrates with top and bottom metal layers perforated with metalized holes, SIW structures offer a compact, low loss, flexible, and cost-effective solution for integrating active circuits, passive components and radiating elements on the same substrate. This paper presents an overview of the current status and future trends of academic and industrial research on SIW technology. The historical development of SIW components and circuits is briefly outlined, and the current research topics are discussed: they include the development of numerical techniques for the modeling and design of SIW components, the investigation of novel compact and broadband interconnects, the determination of design solutions for loss minimization. Future research trends are also discussed: they mainly aim at the implementation of SIW components at higher frequency (60-350 GHz) and the integration of complete Systems-on-Substrate (SoS)

On 't Hooft's S-matrix Ansatz for quantum black holes

The S-matrix Ansatz has been proposed by 't Hooft to overcome difficulties and apparent contradictions of standard quantum field theory close to the black hole horizon. In this paper we revisit and explore some of its aspects. We start by computing gravitational backreaction effects on the properties of the Hawking radiation and explain why a more powerful formalism is needed to encode them. We then use the map bulk-boundary fields to investigate the nature of exchange algebras satisfied by operators associated with ingoing and outgoing matter. We propose and comment on some analogies between the non covariant form of the S-matrix amplitude and liquid droplet physics to end up with similarities with string theory amplitudes via an electrostatic analogy. We finally recall the difficulties that one encounters when trying to incorporate non linear gravity effects in 't Hooft's S-matrix and observe how the inclusion of higher order derivatives might help in the black hole microstate counting.Comment: 22 Pages. Latex Fil

Design of a multi-purpose building "to zero energy consumption" according to european directive 2010/31/ce: Architectural and plant solutions

Considering the significant impact that the residential sector has on energy consumption, it is particularly important to implement policies aimed at improving energy efficiency in buildings for saving primary energy, and also to spread the concept of sustainable development through the use of appropriate technology and proper project criteria for new constructions. For these reasons the Municipality of Città della Pieve promoted the creation of a "Renewable Energy Park" in a deprived area of its territory, so that there were the main technologies for the production of green energy. In this context, it could not be lacking an educational/demonstrative "zero energy consumption" building for multifunctional activities realized with the most innovative techniques to save energy. The building will exemplify the optimization of the benefits derived from improved energy efficiency in synergy with systems of energy production from renewable sources, such as to make possible the transition from "passive" building to get to "active" building. In this paper we describe the technical solutions adopted both in the building envelope and the system concept for the project of that "zero energy consumption" building according to Directive 2010/31/CE. In order to validate the proposed solutions, it has also been carried out a simulation of the behaviour of the building in summer and winter so that it is possible to assess the actual benefits obtained both in terms of energy and in economic terms following the adoption of the proposed solutions

Feasibility study to realize an anaerobc digester fed with vegetables matrices in central Italy

In the present paper we have analysed the possibility to realize an anaerobic digester in a bio-Energy Park located in Città della Pieve, a small town in Central Italy. The use of anaerobic digesters is quite common in Europe for reducing the environmental impact of manure in a co-digestion procedure with vegetables materials. In addition, for several areas of Central Italy there is the need to find alternative productions to improve farmer's incomes, as traditional cropping systems are loosing convenience. An interesting alternative seems to be cultivation of energy crops because of the favourable conditions of the electric energy market. We are suggesting a low input cropping system to be implemented in areas where low input food/feed crops are no more profitable. In particular our case-study is an example based on the use of a forage legume, alfalfa (Medicago sativa L.), together with other crops, like sorghum, to realize small-size bio-digesters plants. Alfalfa: is a highly sustainable crop as it is able to fix nitrogen and therefore it does not require this fertilization with the consequence of avoiding underground water pollution. Moreover alfalfa residual products are nitrogen rich thus improving soil structure and fertility more than popular graminaceous energy crops such as corn. Beside, alfalfa mostly does not need irrigation in the typical Central Italy environment, all these traits make it one of the species with the lowest energy needs for growing. The aims of this feasibility study are: i) optimization of plant materials feeding the bio-digester, ii) typology of bio-digester, iii) size of bio-digester in relation with land availability for growing energetic cultures, iv) the utilization of bio-gas produced by bio-digester plant to produce electric and thermal energy using cogeneration engines, vi) disposal of waste-water produced according to regional and national laws. The final aim of this study is to verify the possibility to develop an alternative economical use of marginal soils in relatively dry areas of Central Italy that would be replicable in other European areas with a similar climatic situation

On the stringy nature of winding modes in noncommutative thermal field theories

We show that thermal noncommutative field theories admit a version of `channel duality' reminiscent of open/closed string duality, where non-planar thermal loops can be replaced by an infinite tower of tree-level exchanges of effective fields. These effective fields resemble closed strings in three aspects: their mass spectrum is that of closed-string winding modes, their interaction vertices contain extra moduli, and they can be regarded as propagating in a higher-dimensional `bulk' space-time. In noncommutative models that can be embedded in a D-brane, we show the precise relation between the effective `winding fields' and closed strings propagating off the D-brane. The winding fields represent the coherent coupling of the infinite tower of closed-string oscillator states. We derive a sum rule that expresses this effective coupling in terms of the elementary couplings of closed strings to the D-brane. We furthermore clarify the relation between the effective propagating dimension of the winding fields and the true codimension of the D-brane

Off-center collisions in AdS_5 with applications to multiplicity estimates in heavy-ion collisions

We study the trapped surface produced by an off-center collision of light-like, point-sourced shock waves in anti-de Sitter space. We find an analytic expression for the shape of the trapped surface in the limit where the energy of the shock waves is large and the impact parameter is not too large. We use the area of the trapped surface to estimate a lower bound on the entropy produced in the collision. We compare our results to particle multiplicity measurements in heavy-ion collisions as interpreted through the Glauber model. In an attempt to roughly simulate the effects of asymptotic freedom and confinement in quantum chromodynamics, we also consider the effects of slicing off parts of anti-de Sitter space.Comment: 43 pages, 12 figures, 2 appendice

Classical central extension for asymptotic symmetries at null infinity in three spacetime dimensions

The symmetry algebra of asymptotically flat spacetimes at null infinity in three dimensions is the semi-direct sum of the infinitesimal diffeomorphisms on the circle with an abelian ideal of supertranslations. The associated charge algebra is shown to admit a non trivial classical central extension of Virasoro type closely related to that of the anti-de Sitter case.Comment: 4 sign mistakes due to a change of conventions are corrected in section 2, none of the conclusions are affected, takes precedence over published version, including corrigendu

Stable non-uniform black strings below the critical dimension

The higher-dimensional vacuum Einstein equation admits translationally non-uniform black string solutions. It has been argued that infinitesimally non-uniform black strings should be unstable in 13 or fewer dimensions and otherwise stable. We construct numerically non-uniform black string solutions in 11, 12, 13, 14 and 15 dimensions. Their stability is investigated using local Penrose inequalities. Weakly non-uniform solutions behave as expected. However, in 12 and 13 dimensions, strongly non-uniform solutions appear to be stable and can have greater horizon area than a uniform string of the same mass. In 14 and 15 dimensions all non-uniform black strings appear to be stable.Comment: 26 pages, 11 figures. V2: reference added, matches published versio