Riviste Online SApienza - R.O.SA - 2 (Sapienza University of Rome)
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Adaptation of ohia pozzolan soil on cemented lateritic soil as base material improvement
Get PDFThe effect of nanostructured Ohia naturally occurring pozzolan (kaolin clay) on the compressive strength of Umuntu Olokoro lateritic soil was investigated for use as base material improvement of south eastern roads. First, a preliminary exercise was conducted to determine the index, grading and consistency properties of the natural soil. The results show that the Umuntu Olokoro soil was an A-2-7 soil, according to AASHTO classification system and poorly graded (GP) on USCS classification. The soil also recorded a PI of 21.85%, which shows that the soil was highly plastic. The specific gravity of the soil was 2.67, OMC of 13%, Maximum Dry Density of 1.84 gm/cm3, California Bearing Ratio of 14%, Unconfined Compressive Strength of 194.26 kN/m2, 219.11 kN/m2 and 230.77 kN/m2 at 7, 14 and 28 days curing periods with material property of silty clayey sand and stiff material. Furthermore, the pozzolan additive was introduced in proportions of 3%, 6%, 9%, 12% and 15% by weight and the effect of the varying proportions studied. The results show that the introduction of the pozzolan improved the soil compressive strength, considerable and a maximum of 369.9 kN/m2 was achieved at 9% proportion of pozzolan at 28 days curing time. Having satisfied the material properties for use as a base material (200-400 kN/m2), pozzolan is a very good admixture material in the stabilization of lateritic soils for use as a subbase material for pavement construction
Assessment of the groutability using secondary permeability index in an arid zone:a case study in Shitab dam site, se Iran
Get PDFThe water seepage through dams’ basement and abutments may result in catastrophic events at down-streams. Therefore, it is critical to seal dam foundation via reasonable methods. To decide a ground treatment strategy, one may not elaborate all necessary data-set especially in areas with very simple geologic properties. This study aims to evaluate the groutability in a very simple geologic condition. For this, the studies conducted along the Shitab Dam basement and abutments axis. The study area is located SE Iran, with an arid climate, where the mechanical weathering is extremely high. The investigation conducted through using 5 boreholes in the study area. The rock quality designation (RQD) index and Lugeon in-situ test were done. Additionally, the secondary permeability index (SPI) calculated using the field observations. The results revealed a serious complexity in engineering properties of the rock mass. Accordingly, the grout curtain pattern designed
Damping measurements from microseismic signals to infer rock mass damaging
Get PDFGeophysical monitoring performed on unstable portions of rock masses can help in defining a variation in its stability conditions, resulting as a useful indicator for landslide risk reduction. In particular, understanding geophysical markers of rock mass damaging, intended as the processes that lead to the formation or to the growth of fractures, could improve risk mitigation strategies. This work illustrates a methodology used to process a microseismic dataset acquired on a 12 m3 rock block prone to failure, located in the Acuto quarry test site, Central Italy. The microseismic monitoring campaign lasted 3 months and was conducted by deploying 6 one-component accelerometers partially on the rock block and partly on the rock mass wall. The acquisition was set in continuous mode and with a sampling frequency of 2400 Hz, allowing to collect hundreds of microseismic events. The damping coefficient of each event has been evaluated for some frequencies of interest, then the values have been averaged and compared through the whole period analysed in order to derive possible variations in the vibrational behavior of the monitored rock block. Despite no relevant changes have been noted, this technique could be helpful for analysing bigger datasets or to study different sites in which the external stresses are more intense and recurrent
Description of two new species of Calodromus Guérin-Méneville, 1832 from Peninsular Malaysia (Coleoptera: Brentidae, Cyphagoginae)
Get PDFCalodromus mantillerii n. sp. and Calodromus goosseni n. sp. from Perak (Malaysia) are described on two single male specimens. The new taxa are closely related to Calodromus insignis (Senna, 1895) but can be easily distinguished by the very different shape of the first tarsal article of the male hind legs. A key for the identification of the males of the three known species of the Calodromus insignis group is provided. A new locality record of Calodromus insignis from Malaysia is also given
Zelus renardii (Kolenati, 1856), a newly established alien species in Italy (Hemiptera: Reduviidae, Harpactorinae)
Get PDFThis note adds new occurrence records of the hemipteran alien species Zelus renardii (Kolenati, 1856) in Italy by citizens, entomologists and photographers. This species was recorded for first time in Rome in 2013
Flower visitation of Passiflora apetala, P. auriculata and P. holosericea (Passifloraceae) by Pepsis aquila (Hymenoptera: Pompilidae)
Get PDFPepsis aquila (Hymenoptera: Pompilidae) is reported as an assiduous flower visitor and possible pollinator of Passiflora apetala, P. auriculata and P. holosericea in Costa Rica. The vertex and scutellum of P. aquila becomes abundantly covered with pollen while collecting the nectar from the cup nectaries of Passiflora. The Passiflora visited by P. aquila share some floral characteristics with previously reported plants pollinated by pompilids in Africa
The IBI/BEI project: monitoring bilingual education in primary schools
No full textThis paper tackles an example of bilingual education in primary education presenting a project carried out at primary school level on the teaching of three subjects (i.e. Science, Geography, Art) delivered in English, which was also the language for class interaction, to provide a fully immersive educational environment. The project, called IBI/BEI (Insegnamento Bilingue ItaliaBilingual Education Italy), was developed by the Italian Ministry of Education, the British Council Italy and the USR Lombardia (the Regional Education Office of Lombardy) on the basis of a project implemented in Spain in 1996. This study provides the data collected during a monitoring activity on the project and reflects on the best practices for promoting bilingual education in the early stages of learning. Results demonstrate that the IBI/BEI project set out to prepare children to face the challenge of internationalization, but also showed a major limitation, as it did not continue in the subsequent stages of education. This drawback was mentioned by all the actors involved in the study, who expressed their concern towards such a valuable initiative being a oneoff experience
Economic growth in Eastern, Central And Southern European countries. An econometric analysis of the components of their public spending
No full textSince the entry into force of the Stability and Growth Pact, European countries with “weak fiscal policy fundamentals” have been forced to introduce fiscal measures for controlling public spending to achieve and maintain the objectives required by the Maastricht Treaty. The financial crisis of 2008 and 2009 caused a strong reduction in GDP and investments, and an increase in social disparities. Consequently, the gap between European Southern countries (as well as Central Eastern countries) and the rest of the European Union became wider in several ways. The need of financial resources for multi-annual reforms and investments makes it crucial for these governments to reflect on the relevance of public spending in terms of the economic effects of redistributive politics of pure transfers to households versus dynamic adjustments of public capital accumulated in the recipient economy. The present paper aims at empirically verifying the economic effect of two public spending components such as social transfers and public gross fixed capital formation, in Eastern, Central and Southern European countries, in a compliance context with public spending control. The econometric analysis is based on a dynamic panel regression. The main finding is that public gross fixed capital formation and, to a lower extent, social benefits other than transfers in-kind have significant effects on economic growth (positive and negative, respectively)
Gender bias in China and India: an evaluation of “missing girls”
No full textPrevious research has shown the existence of severe gender discrimination in China and India dramatically affecting female survival during childhood, due to the lack of equity between sexes in the access to primary needs, like food and health care. Excess female mortality, together with antenatal discrimination, have caused imbalanced sex ratios with an estimate of 100 million “missing women” at the global level. The main goal of this study is to evaluate female deficit in China and India, distinguishing between the two main causes of the female shortage: prenatal and postnatal discrimination. Such a distinction is essential to the development of effective contrasting actions. The results show that despite – in relative terms - the overall reduction in female deficit in both countries during the 1980-2000 period, the discrimination against girls persisted during childhood and adolescence
