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Adobe is a construction technique that uses raw clayey earth mixed and moulded to form blocks to realize a bearing wall. Romans were also used to add sand or coarse sand into the mixture to “degrease” clay and to allow to make it into a mixture. Fibres such as straw were often added into the mixture. Anyway, ancient home brick-makers have not had a chance to do scientific experimental investigation on the balance of ingredients and the optimisation of this production. This paper elaborates on how workability and mechanical properties of Roman ancient adobe earthen bricks change by varying the percentage of an on situ soil, straw and coarse sand into the mixture to produce them. The comparisons were also made with the only-earth samples. Breaking manners of all the samples were also compared. 相似文献
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This paper analyzes the implementation of new intermunicipal structures in Italy to support the development of E-Government in the country's peripheral areas. Our exploratory case study, conducted in the Piedmont Region, shows that intermunicipal collaborations can facilitate the coordination of interdependent subjects, rationalize existing resources (e.g., through the reuse of application software solutions), and prevent the dispersion of federal government funds. Nevertheless, intermunicipal collaborations alone do not seem to have the power needed to ensure that decisions made at the central level will automatically translate into concrete and binding commitments for the municipalities involved. From a methodological standpoint, the article makes use of the analytical frameworks offered by organization science to interpret the effects of collaborative arrangements on E-Government implementation. 相似文献
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Enrico E. Bertacchini Chiara Dalle Nogare Raffaele Scuderi 《Journal of Cultural Economics》2018,42(4):619-643
This article provides an empirical investigation of the effects of the ownership and organizational structure on the performance of cultural institutions. More specifically, we consider how museums are effective in their function of disseminating culture to audiences and contributing to the local development. By exploiting a unique data set based on the 2011 census of Italian museums, we develop performance indices of accessibility, visitors’ experience, web visibility and promotion of the local cultural context. Using count data models, we regress such measures on the type of organization. We distinguish between governmental museums, public museums whose administration is either outsourced or has financial autonomy and private museums. We control for the most salient characteristics of a museum, competition pressure and some proxies of potential audience. Our evidence shows that private museums, public museums with financial autonomy and outsourced museums outperform public museums run as sub-units of culture departments. This paper contributes to the cultural economics and public policy and administration literature by adding insights into the effect of outsourcing and administrative decentralization in the public cultural sector. 相似文献
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Enrico R. A. Giannetto 《Science & Education》2009,18(6-7):765-781
The revolution in XX century physics, induced by relativity theories, had its roots within the electromagnetic conception of Nature. It was developed through a tradition related to Brunian and Leibnizian physics, to the German Naturphilosophie and English XIXth physics. The electromagnetic conception of Nature was in some way realized by the relativistic dynamics of Poincaré of 1905. Einstein, on the contrary, after some years, linked relativistic dynamics to a semi-mechanist conception of Nature. He developed general relativity theory on the same ground, but Hilbert formulated it starting from the electromagnetic conception of Nature. Here, a comparison between these two conceptions is proposed in order to understand the conceptual foundations of special relativity within the context of the changing world views. The whole history of physics as well as history of science can be considered as a conflict among different worldviews. Every theory, as well as every different formulation of a theory implies a different worldview: a particular image of Nature implies a particular image of God (atheism too has a particular image of God) as well as of mankind and of their relationship. Thus, it is very relevant for scientific education to point out which image of Nature belongs to a particular formulation of a theory, which image comes to dominate and for which ideological reason. 相似文献
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Peter Labudde Walter Herzog Markus P. Neuenschwander Enrico Violi Charlotte Gerber 《International Journal of Science Education》2013,35(2):143-157
In this quasi-experimental study various strategies are developed and empirically tested for an approach to physics instruction that should improve girls' and boys' attitudes toward and achievements in physics. Strategies include opportunities to integrate different pre-existing knowledge and the variation of teaching methods to enhance co-operation and communication in the classroom. The core of this study is an intervention in 31 classes of public schools in Switzerland. The intervention, one unit in optics and one in motion (velocity/acceleration), includes the first 40 lessons of the first physics course that all students have to attend at the upper secondary level. Data sources are various student and teacher questionnaires, tests and semi-structured interviews with teachers. Results of the entrance and final survey are presented. The focus will be on some of the applied strategies. Implications for the teaching and learning of physics and for teacher education are discussed. 相似文献
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This paper shows that the conditionality of investment decisions in R&D has a critical impact on portfolio risk, and implies that traditional diversification strategies should be reevaluated when a portfolio is constructed. Real option theory argues that research projects have conditional or option-like risk and return properties, and are different from unconditional projects. Although the risk of a portfolio always depends on the correlation between projects, a portfolio of conditional R&D projects with real option characteristics has a fundamentally different risk than a portfolio of unconditional projects. When conditional R&D projects are negatively correlated, diversification only slightly reduces portfolio risk. When projects are positively correlated, however, diversification proves more effective than conventional tools predict. 相似文献
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Recumbent bicycles (RB) are high performance, human-powered vehicles. In comparison to normal/upright bicycles (NB) the RB may allow individuals to reach higher speeds due to aerodynamic advantages. The purpose of this investigation was to compare the non-aerodynamic factors that may potentially influence the performance of the two bicycles. 3D body centre of mass (BCoM) trajectory, its symmetries, and the components of the total mechanical work necessary to sustain cycling were assessed through 3D kinematics and computer simulations. Data collected at 50, 70, 90 110 rpm during stationary cycling were used to drive musculoskeletal modelling simulation and estimate muscle-tendon length. Results demonstrated that BCoM trajectory, confined in a 15-mm side cube, changed its orientation, maintaining a similar pattern across all cadences in both bicycles. RB displayed a reduced additional mechanical external power (16.1 ± 9.7 W on RB vs. 20.3 ± 8.8 W on NB), a greater symmetry on the progression axis, and no differences in the internal mechanical power compared to NB. Simulated muscle activity revealed small significant differences for only selected muscles. On the RB, quadriceps and gluteus demonstrated greater shortening, while biceps femoris, iliacus, and psoas exhibited greater stretch; however, aerodynamics still remains the principal benefit. 相似文献
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Nicola Giovanelli Paolo Taboga Enrico Rejc Stefano Lazzer 《European Journal of Sport Science》2017,17(7):805-813
The aim of the present study was to evaluate the effects of a 12-week home-based strength, explosive and plyometric (SEP) training on the cost of running (Cr) in well-trained ultra-marathoners and to assess the main mechanical parameters affecting changes in Cr. Twenty-five male runners (38.2?±?7.1 years; body mass index: 23.0?±?1.1?kg·m?2; V˙O2max: 55.4?±?4.0 mlO2·kg?1·min?1) were divided into an exercise (EG?=?13) and control group (CG?=?12). Before and after a 12-week SEP training, Cr, spring-mass model parameters at four speeds (8, 10, 12, 14?km·h?1) were calculated and maximal muscle power (MMP) of the lower limbs was measured. In EG, Cr decreased significantly (p?<?.05) at all tested running speeds (?6.4?±?6.5% at 8?km·h?1; ?3.5?±?5.3% at 10?km·h?1; ?4.0?±?5.5% at 12?km·h?1; ?3.2?±?4.5% at 14?km·h?1), contact time (tc) increased at 8, 10 and 12?km·h?1 by mean +4.4?±?0.1% and ta decreased by ?25.6?±?0.1% at 8?km·h?1 (p?<?.05). Further, inverse relationships between changes in Cr and MMP at 10 (p?=?.013; r?=??0.67) and 12?km·h?1 (p?<?.001; r?=??0.86) were shown. Conversely, no differences were detected in the CG in any of the studied parameters. Thus, 12-week SEP training programme lower the Cr in well-trained ultra-marathoners at submaximal speeds. Increased tc and an inverse relationship between changes in Cr and changes in MMP could be in part explain the decreased Cr. Thus, adding at least three sessions per week of SEP exercises in the normal endurance-training programme may decrease the Cr. 相似文献
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Enrico Quagliarini Federica Bondioli Giovanni B. Goffredo Antonio Licciulli Placido Munafò 《Journal of Cultural Heritage》2012,13(2):204-209
The development and application of self-cleaning treatments on historical and architectural stone surfaces could be a significant improvement in conservation, protection and maintenance of Cultural Heritage. In this paper, a TiO2-based coating has been investigated in order to evaluate its possible use as a self-cleaning treatment. This coating was obtained by a sol-gel and a hydrothermal (134 °C) processes and then it was applied on travertine (a limestone often used in historical and monumental buildings) in two ways, obtaining a single-layer and a three-layer treatment, respectively. In order to verify its potential use in the field of Cultural Heritage, the maintenance of appearance properties of the treated travertine surfaces was monitored by colour and gloss analyses. Besides, de-pollution and soiling removal tests were carried out under ultraviolet-light exposure to evaluate photo-induced effects and self-cleaning efficiency. Results seem to allow the use of TiO2-based treatments on historical and architectural surfaces made up by travertine, where de-pollution and self-cleaning photo-induced effects are well evident, maintaining their original visual appearance. Anyway, before applying TiO2-based coatings as conservative treatments, further tests are needed especially on their durability, that is mandatory for Cultural Heritage applications. On-site test in an urban environment and accelerated test by weatherometer are currently under way. 相似文献