104 research outputs found
Assessment of the release of metals from cigarette butts into the environment
Cigarette butts are known to contain toxic metals which pose a potential threat to the environment and human health. The seriousness of this threat is largely determined by the leachability of these toxic metals when the butts are exposed to aqueous solutions in the environment. The aims of this study were to determine the presence and mobility of toxic and non-toxic elements found in discarded cigarette butts; to relate this mobility to two different contact situations with leaching liquids: tumbling and trampling (batch test) and percolation in a static position (column test); and finally, to verify possible variations in solubility by simulating different environmental systems. Five leachants with different pH values were used to simulate various environmental conditions The concentrations of the solubilized metals were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). CH3COOH pH 2.5 showed the greatest capacity to dissolve many elements. On the contrary, weakly acidic or alkaline environments did not favor the leachability of the elements. The best extraction capacity of the column with respect to the batch is statistically significant (p <0.05) for the elements Al, Fe, Ni and Zn, while the batch for P, Si, S. Pb, Cd, As were not detectable in cigarette butts, while Hg had an average concentration of 0.0502 μg/g. However, Hg was < LOD in all different leachants
Shake table testing of a low-impact technology for the seismic protection of stone masonry
This paper presents a novel low-impact technique for the seismic protection of fair-face masonry walls. The proposed strengthening solution involves the use of carbon-fibre reinforced polymer (CFRP) connectors installed from the outside by perforating the stone elements, combined with grout injections. The connectors cover ¾ of the wall thickness, so as to leave the inner surface undisturbed. Once the work is completed, they are also substantially invisible. Shake table tests were carried out under natural accelerograms on two full-scale irregular multi-leaf stone masonry wall specimens. In order to replicate materials and construction technique of the Apennine historical buildings, the prototypes were made from stones recovered from the debris of a settlement in the municipality of Accumoli (RI, Italy), and the mortar was designed to reproduce lime-poor mortars surveyed in the field. The experimental setup was designed to induce out-of-plane vertical bending under base seismic motion, while allowing the vertical displacement of the wall top. One specimen was tested “as-built” and the other one was tested strengthened, to investigate the gain in seismic performance, the limitation of progressive damage accumulation and the effects on dynamic properties
mutual validation between different modal analysis techniques for dynamic identification of the so called temple of minerva medica rome
The dynamic identification by ambient vibration data is widely used to supply information on the global health of structures through the investigation of changes in their modal parameters. It can be used even for verification of the state of damage of structures after hazardous threats, for example seismic activity. Therefore, it can play a crucial role to integrate and support conservation strategies for historic architectural assets. Sometimes, in historic constructions only a limited number of positions are accessible or usable to install sensors, and so modal analysis must be based on data from few measurement points. Moreover, they might not be the optimal positions for the studied structure, so the obtained results would need further verification. In such circumstances, the mutual validation between different modal analysis techniques can be useful to assess the reliability of results. In the present paper a case study of application to the so-called Temple of Minerva Medica, Rome, is described. Ambient vibration data were acquired in four rowing acquisition sessions carried out from July 2016 to July 2017, which is a timespan usable to assess the impact of the recent Central Italy seismic sequence. For problems related to the installation of the scaffolding only few points were available for instruments positioning. A variety of techniques were applied, including FRF, FDD, EFDD, SSI, HVSR and complex modal models. The variance of the modal parameters obtained by each different technique was utilized to provide indications on the reliability of the average values
Advanced Video-Based Processing for Low-Cost Damage Assessment of Buildings under Seismic Loading in Shaking Table Tests
This paper explores the potential of a low-cost, advanced video-based technique for the
assessment of structural damage to buildings caused by seismic loading. A low-cost, high-speed video
camera was utilized for the motion magnification processing of footage of a two-story reinforcedconcrete
frame building subjected to shaking table tests. The damage after seismic loading was
estimated by analyzing the dynamic behavior (i.e., modal parameters) and the structural deformations
of the building in magnified videos. The results using the motion magnification procedure were
compared for validation of the method of the damage assessment obtained through analyses of
conventional accelerometric sensors and high-precision optical markers tracked using a passive
3D motion capture system. In addition, 3D laser scanning to obtain an accurate survey of the
building geometry before and after the seismic tests was carried out. In particular, accelerometric
recordings were also processed and analyzed using several stationary and nonstationary signal
processing techniques with the aim of analyzing the linear behavior of the undamaged structure and
the nonlinear structural behavior during damaging shaking table tests. The proposed procedure
based on the analysis of magnified videos provided an accurate estimate of the main modal frequency
and the damage location through the analysis of the modal shapes, which were confirmed using
advanced analyses of the accelerometric data. Consequently, the main novelty of the study was
the highlighting of a simple procedure with high potential for the extraction and analysis of modal
parameters, with a special focus on the analysis of the modal shape’s curvature, which provides
accurate information on the location of the damage in a structure, while using a noncontact and
low-cost method
Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores
A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació
Trace elements, 210Po and 210Pb in a selection of berries on commercial sale in Italy
The occurrence of 210Pb, 210Po, trace elements was assessed in a selection of berries on commercial sale in Italy. Data confirmed that berries might serve as an important source of essential elements. The 210Pb, 210Po concentrations found were higher than the reference values reported by UNSCEAR for roots and fruits in the world. There is no risk whatsoever from the intake of toxic elements as Al, As, Cd, Pb, Ni, Hg in berriberries analyzed; it is necessary, however, continuously monitored the levels of these elements to protect consumers against potential adverse health effects especially when consumed in large quantities
Essential and toxic elements in honeys consumed in Italy
The aim of this study was to determine the levels of iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), zinc (Zn), mercury (Hg), cadmium (Cd) and lead (Pb) in several types of honey purchased from the local consumer markets in Central Italy by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Lead and Cd were also determined by Atomic Absorption Spectrometry with graphite tube atomization (AAS-GTA). The degree of humidity, sugar content, pH, free acidity, combined acidity (lactones) and total acidity were also measured. These elements were found to be present in honeys in various proportions depending upon (1) area foraged by bees, (2) flower type visited for collection of nectar, and (3) quality of water in the vicinity of the hive. The honeys consumed in Italy were of good quality, but not completely free of heavy metal contamination. Compared with established recommended daily intakes, heavy metals or trace element concentrations in samples investigated however, do not pose any serious concern to human health
Toxic elements in human saliva of smokeless tobacco users
The occurrence and mobility of different elements in oral smokeless tobacco products (STPs) were determined because the effects on human health must take into account their availability. In this research, the elemental analysis of 15 oral smokeless tobacco products of different brands purchased in local specialty stores in Europe, and the determination of % extraction of the different elements into an artificial salivary juice during the sucking or chewing operations were performed. In all samples analyzed, cobalt (Co) and chromium (Cr) (total) levels were < 0.326 mg/kg ww. As far as non-essential or toxic elements, U was always < 1.0 mg/kg, Th and Ti < 0.1 mg/kg, Cd was <0.5. Pb was detectable in 60% of the samples, As in 33.3 % and Ce in 20% of the samples; La was <1 mg/kg in 13 samples; Sb was <5 mg/kg in all sample with exception of sample 13; Al, Ni, Sr, Rb, Ba, Sn, Te, Ti and Hg were detectable in all samples. Using artificial saliva, the data of extractable levels show that the toxic elements, although poorly extracted, are not totally retained within the smokeless tobacco products, with a consequent potential health hazard associated with oral use of these products
Bioaccessibility assessment of stable elements and 210Po in food
Element bioaccessibility consists of the fraction of the element that is mobilized from food
matrices into digestive extractants. The degree of bioaccessibility of a toxic metal is a fundamental
consideration in estimating its bioavailability. In addition, gaining a better understanding
of the essential elements released into the gastro intestinal fluids allows a more
thorough assessment of the health benefits of food matrices in the field of nutrition science.
In the present study, an in vitro digestion model simulating gastro-intestinal digestion (GID)
was used to investigate the bioaccessibility of stable elements in mixed leaf salad and 210Po
in various foods (meat, seafood, vegetables). The simulation was carried out over three
phases: after a pre-treatment with a saliva solution, raw and cooked seafood samples were
subjected to a complete simulated gastrointestinal digestion (gastric digestion followed by
bile-pancreas digestion). The 210Po bioaccessibility was found to range from 16.2±9.39% to
62.8±17.7% and from 6.26±2.15% to 67.5±13.1% for raw and cooked food respectively.
Moreover, bioaccessibility could not be determined for As, Cd, Ce, Co, Cr, Hg, La, Pb, Sb,
Sn, Te, Th, Tl, Ti, U. It proved to be poor (1–16%) for Al, Fe and S; fair (40–50%) for Cu, P,
and Si; and high (>50%) for Ba, Ca, K, Mg, Mn, Ni, Rb, Sr, Zn. The results show that bioaccessibility
varies according to the chemical form of the element in the food as well as the
matrix composition
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