1,721,232 research outputs found
Charged particles and cluster ions produced during cooking activities
No full textPrevious studies showed that a significant number of the particles present in indoor air are generated by cooking activities, and measured particle concentrations and exposures have been used to estimate the related human dose. The dose evaluation can be affected by the particle charge level which is usually not considered in particle deposition models. To this purpose, in this paper we show, for the very first time, the electric charge of particles generated during cooking activities and thus extending the interest on particle charging characterization to indoor micro-environments, so far essentially focused on outdoors. Particle number, together with positive and negative cluster ion concentrations, was monitored using a condensation particle counter and two air ion counters, respectively, during different cooking events. Positively-charged particle distribution fractions during gas combustion, bacon grilling, and eggplant grilling events were measured by two Scanning Mobility Particle Sizer spectrometers, used with and without a neutralizer. Finally, a Tandem Differential Mobility Analyzer was used to measure the charge specific particle distributions of bacon and eggplant grilling experiments, selecting particles of 30, 50, 80 and 100 nm in mobility diameter. The total fraction of positively-charged particles was 4.0%, 7.9%, and 5.6% for gas combustion, bacon grilling, and eggplant grilling events, respectively, then lower than other typical outdoor combustion-generated particles
A comparison of submicrometer particle dose between Australian and Italian people
No full textAlveolar and tracheobronchial-deposited submicrometer particle number and surface area data received by different age groups in Australia are shown. Activity patterns were combined with microenvironmental data through a Monte-Carlo method. Particle number distributions for the most significant microenvironments were obtained from our measurement survey data and people activity pattern data from the Australian Human Activity Pattern Survey were used.\ud
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Daily alveolar particle number (surface area) dose received by all age groups was equal to 3.0×1010 particles (4.5×102 mm2), varying slightly between males and females. In contrast to gender, the lifestyle was found to significantly affect the daily dose, with highest depositions characterizing adults. The main contribution was due to indoor microenvironments. \ud
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Finally a comparison between Italian and Australian people in terms of received particle dose was reported; it shows that different cooking styles can affect dose levels: higher doses were received by Italians, mainly due to their particular cooking activity
Unequally excited generalised random binned antenna arrays
No full textIt has been recently shown that random arrays paired with a proper excitation strategy can be used to shape the array factor. These random arrays were termed unequally excited totally random arrays (TRAs). This scheme allows to greatly enlarge the class of obtainable patterns, well beyond the classical single beam. However, its main disadvantage is a reduction of the achievable performance, the latter measured in terms of the deviation from the average array factor. In this contribution, a strategy for remedying (even only partially) to such a loss of performance by retaining the same flexibility in shaping the pattern is addressed. To this end, a new scheme for generating random arrays that merges unequal excitations and a suitable generalised binned procedure is introduced. It is shown that this new model of generalised binned arrays always outperforms unequally excited TRAs. In particular, the study is focused on symmetric arrays (for which the elements are deployed symmetrically with respect to the array aperture centre) which allows to get closed-form expressions without invoking some common assumptions that in general do not hold true in practice. The theoretical findings are assessed by several numerical examples for the case of multi-beam array factors
Ordinary Minds on Remediated Days. Television and Media in 'Saturday' by Ian McEwan
No full textIan McEwan is well known for the remediation he operated on his own works from literature to cinema (The Cement Garden, The Innocent, Enduring Love, Atonement, just to mention the most popular ones). In my paper, however, I am going to focus on how literature is remediated by television, and media in general, by examining how McEwan, in his novel Saturday, though presenting a work clearly recalling modernist narrative structures, shows the way in which humans, under the influence of several media, are remediated.
Saturday has been described as an allegory of the post-9/11 world (Dirda; Fortin Tournes), and in fact McEwan here mainly concentrates on the impact of the tragedy of 9/11 on culture and society, and uses media, mainly television, to show how they influence the processes of the human mind. The novel has also been widely associated with Woolf’s Mrs Dalloway and Joyce’s Ulysses for its modernist structure (Head; Groes; Wells). I here wish to analyse how McEwan uses television and media to rewrite and transform modernist literary forms in Saturday, in which media are represented as shaping our minds and ways of perceiving the world. What is most interesting is that, in the novel, things only seem real when they appear in the news; thus the protagonist keeps watching the news to make the event he witnessed in the morning (what he calls “his news”) real. But the news always fails to provide him with an answer or an explanation, and the understanding of reality only arrives, at the end of the novel, through a kind of epiphany triggered by poetry.
I will also examine how McEwan uses media (television, internet, mobiles) to characterize and contextualize his characters, who are defined by the use they make of them. I will finally analyse how television, being a recurring element in the narration, sets the rhythm of the protagonist’s ‘stream’ of thoughts; indeed it appears nine times and plays a role similar to that of the Big Ben in Woolf’s Mrs. Dalloway.
Ian McEwan writes a novel concerned with the role and influence of media, examining how, penetrating our minds and brains, they become an integral part of them. In an age which keeps asking how new media can affect, influence, inspire, or be detrimental to literature, the British writer manages to represent their influence on our lives without bending his narrative structures to media’s new languages and forms. On the contrary, he absorbs them into the narration and represents them through the remediation they operate on human minds
Microwave imaging through an unknown wall by a MIMO configuration and SVD approach
No full textAs is well known, in through-the wall imaging one needs to estimate the wall electromagnetic parameters in order to get properly focused images. Even under the simplest case in which the wall can be assimilated as a single homogeneous slab, this problem puts some difficulties since the wall dielectric permittivity and thickness are non-linearly linked to the reflected field data. The usual way to go on that problem is through some optimization iterative procedure which can be time consuming and can suffer from false solutions. In this contribution we propose a method that avoids the previously mentioned drawbacks by leveraging on a MIMO configuration. The main idea is to estimate the wall transmission coefficient rather than its electromagnetic properties. This way, one estimates the kernel of the relevant (for imaging) scattering operator instead of constructing it after wall parameters have been estimated. More in detail, it is shown that the characterization stage is cast as a linear inverse problem which is solved by a Truncated-Singular Value Decomposition method. The proposed method avoids optimization but in principle can be applied only for lossless walls. However, multi layered walls can be dealt with as well. In this contribution we focus only on the wall transmission coefficient estimation; once it has been obtained imaging can be achieved by standard back-propagation algorithms. In particular, the study is developed for a single wall and 3D vector case and some numerical examples are reported to check the theory
Lung cancer risk of airborne particles for Italian population
No full textAirborne particles, including both ultrafine and supermicrometric particles, contain various carcinogens. Exposure and risk-assessment studies regularly use particle mass concentration as dosimetry parameter, therefore neglecting the potential impact of ultrafine particles due to their negligible mass compared to supermicrometric particles. The main purpose of this study was the characterization of lung cancer risk due to exposure to polycyclic aromatic hydrocarbons and some heavy metals associated with particle inhalation by Italian non-smoking people. A risk-assessment scheme, modified from an existing risk model, was applied to estimate the cancer risk contribution from both ultrafine and supermicrometric particles. Exposure assessment was carried out on the basis of particle number distributions measured in 25 smoke-free microenvironments in Italy. The predicted lung cancer risk was then compared to the cancer incidence rate in Italy to assess the number of lung cancer cases attributed to airborne particle inhalation, which represents one of the main causes of lung cancer, apart from smoking. Ultrafine particles are associated with a much higher risk than supermicrometric particles, and the modified risk-assessment scheme provided a more accurate estimate than the conventional scheme. Great attention has to be paid to indoor microenvironments and, in particular, to cooking and eating times, which represent the major contributors to lung cancer incidence in the Italian population. The modified risk assessment scheme can serve as a tool for assessing environmental quality, as well as setting up exposure standards for particulate matter
Variability of airborne particle metrics in an urban area
No full textIn the present study a mobile monitoring approach (i.e. bike with onboard instruments) was proposed and applied to investigate the spatial variability of all the key airborne particle metrics in an Italian urban area from a statistical point of view. Particle number, alveolar-deposited surface area, and PM<sub>10</sub> concentrations were measured through hand-held monitors and compared to simultaneous background concentrations by means of non-parametric tests and further post-hoc tests (Kruskal-Wallis test). Streets characterized by exposure levels statistically higher than the background levels for all the particle metrics were identified for different seasons in a pilot urban area (Cassino, Italy). A higher number of hot spots was detected for metrics affected by ultrafine particles (i.e. number and alveolar-deposited surface area concentrations) with respect to PM<sub>10</sub>. The effect of metrological requirements of the instrumentation on the proposed method was also discussed
Direct and indirect measurement of WBGT index in transversal flow
No full textISO 7243 considers the WBGT (Wet Bulb Globe Temperature) index as an index of thermal stress in hot environments. It can be evaluated directly by measuring the globe temperature, the natural wet bulb temperature, and the air temperature (only outside in the presence of solar radiation) or, indirectly, by measuring the air temperature, the air velocity, the humidity and the mean radiant temperature. The globe and natural wet bulb temperatures can only be estimated empirically, because they are not thermodynamic properties. The direct method, thus, permits neither very accurate measurements nor direct traceability. The aim of this study is to compare the above-mentioned methodologies experimentally. This analysis was carried out by varying the thermal and fluid dynamic parameters for transversal flow in the common measurement range
Phase-Only Excited Random Antenna Arrays
No full textUsually random arrays have uniform amplitudes along the aperture and only contemplate a linear phase shift between antenna elements. In this paper, we show, through some numerical results, that it is possible to obtain great flexibility on the radiation pattern by exploiting the potential of phase-only excited random arrays. Indeed, when the phase-tapering along the array aperture is nonlinear, it is possible to obtain radiation patterns with characteristics that can not be obtained with conventional equally-excited random arrays
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