The dry deposition process is recognized as an important pathway among the various removal processes of pollutants in the atmosphere. In this field, there are several models reported in the ...literature useful to predict the dry deposition velocity of particles of different diameters but many of them are not capable of representing dry deposition phenomena for several categories of pollutants and deposition surfaces. Moreover, their applications is valid for specific conditions and if the data in that application meet all of the assumptions required of the data used to define the model. In this paper a new dry deposition velocity model based on an electrical analogy schema is proposed to overcome the above issues. The dry deposition velocity is evaluated by assuming that the resistances that affect the particle flux in the Quasi-Laminar Sub-layers can be combined to take into account local features of the mutual influence of inertial impact processes and the turbulent one. Comparisons with the experimental data from literature indicate that the proposed model allows to capture with good agreement the main dry deposition phenomena for the examined environmental conditions and deposition surfaces to be determined. The proposed approach could be easily implemented within atmospheric dispersion modeling codes and efficiently addressing different deposition surfaces for several particle pollution.
•Dry deposition process is an important pathway to remove pollutants in atmosphere.•A new dry deposition velocity model based on electrical analogy schema is proposed.•The model can be applied for different deposition surfaces.•This approach can easily implemented in atmospheric dispersion modeling codes.
Abstract
Long-range transport and deposition analyses of 137Cs following a hypothetical incident at Gösgen nuclear power plant are studied by using CALMET-CALPUFF model system. Comparisons are ...performed with results obtained from a version modified of CALPUFF using a new dry deposition velocity model. This model is based on a combination of aerodynamic resistances and considers local features of the mutual influence of inertial impact and turbulent processes. The results show that the modified CALPUFF code seems to be an appropriate tool for performing impact assessments on long-range transport in complex terrain contexts or to support preparedness and response capabilities for nuclear and radiological accidents.
Selective Production of Exotic Species is an innovative plant for advanced nuclear physic studies. A radioactive beam, generated by using an UCx target-ion source system, is ionized, selected and ...accelerated for experimental objects. Very high vacuum conditions and appropriate safety systems to storage exhaust gases are required to avoid radiological risk for operators and people. In this paper, Failure Mode, Effects, and Criticality Analysis of a preliminary design of high activity gas recovery system is performed by using a modified Fuzzy Risk Priority Number to rank the most critical components in terms of failures and human errors. Comparisons between fuzzy approach and classic application allow to show that Fuzzy Risk Priority Number is able to enhance the focus of risk assessments and to improve the safety of complex and innovative systems such as those under consideration.
Dry deposition of particle on urban areas Giardina, M; Buffa, P; Cervone, A ...
Journal of physics. Conference series,
05/2019, Letnik:
1224, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Dry deposition process is recognized as an important pathway among the removal processes of radioactive pollutants in atmosphere. There is not a unique and accepted theoretical description of ...involved dry deposition phenomena due to the complexity of the fluid-dynamic processes that influence the deposition flux, but also because there is a lack of experimental data covering all scenarios of interest. In this paper, that is the result of a National Research Program a research activity conducted by DEIM Department of the University of Palermo and ENEA and funded by the Italian Minister of Economic Development, a new schema for parameterization of particle dry deposition velocity on urban area is proposed. The work required comparisons with some experimental data reported in literature for different particle deposition scenarios. The results show that the proposed approach can catch some aspects of phenomena involved in dry deposition processes for the examined environmental conditions with good agreements.
•Human errors in Isotope Separation On-Line (ISOL) facility is performed.•Integrated approach of Hierarchical Task Analysis and Human Reliability Analysis is used.•A modified HEART approach is ...proposed.•HEART, SPAR-H, and CREAM are compared to each other.
SPES (Selective Production of Exotic Species) is a second-generation Isotope Separation On-Line (ISOL) facility for advanced nuclear physics applications, currently under construction at INFN (National Institute of Nuclear Physics) of Legnaro, Italy. Despite the potentially important safety implications of human errors for ISOL facilities, only a limited number of studies addressing this issue have been performed worldwide. This paper tries to address this need by means of an integrated approach of Hierarchical Task Analysis (HTA) and three human error quantification methods: HEART (in an enhanced version), SPAR-H, and CREAM. The application of multiple Human Reliability Analysis (HRA) methods adds credibility to the analysis results and, for the present paper, this is required because the methods are applied to different performance conditions than typical, i.e. for operators in a nuclear power plant control room. The study emphasizes the potential range of task failure probabilities obtained in the analyses, rather than best-estimate values. Since the facility is being constructed, with elements such as the human-machine interface still undergoing design, some of the inputs typically required by HRA methods were not available; consequently, the produced HEP estimates may not fully represent future performance. The obtained results allowed informing some safety-enhancing recommendations that, coming at early stage, could be considered for implementation by the facility designers and managers.
•Evaluate the suitability of a site for nuclear installations.•A Meteorological Pressure Index (MPI) is developed to identify sites with resilience capacity in terms of atmospheric transport ...phenomena.•Natural wind actions on a regional scale is taken into account.•MPI is able to aggregate meteorological data on a regional level and create maps.
Today, the evaluation of a site for innovative nuclear installations represents a fundamental step in supporting the implementation of a sustainable nuclear power program. One major concern is the potential for radioactive releases and their effects on the biosphere, particularly on human health. To address this issue, a new Meteorological Pressure Index (MPI) has been developed to identify sites with resilience capacity in terms of transport phenomena correlated to natural wind actions on a regional scale. The MPI utilizes a fuzzy approach that combines data on 3D wind speed, direction, and frequency, providing maps that are useful in the site selection process. The application of MPI in the Sicily region of Italy has allowed to identify bordering areas that that are more affected by efficient air mass transport mechanisms. Consistency analyses have been conducted among MPI maps, observed wind distributions using wind rose charts, and stagnation S and recirculation R factors. The results confirm the MPI's ability to aggregate meteorological data on a regional level, making it a suitable tool when compared to disaggregated data that may not always provide a comprehensive viewpoint.
In the framework of a National Research Program funded by the Italian Minister of Economic Development, the Department of Energy, Information Engineering and Mathematical Models (DEIM) of Palermo ...University and ENEA Research Centre of Bologna, Italy are performing several research activities to study physical models and mathematical approaches aimed at investigating dry deposition mechanisms of radioactive pollutants. On the basis of such studies, a new approach to evaluate the dry deposition velocity for particles is proposed. Comparisons with some literature experimental data show that the proposed dry deposition scheme can capture the main phenomena involved in the dry deposition process successfully.
Thirty-six patients with unsatisfactory treatment of neurogenic bowel dysfunctions (NBD) were enrolled from Spinal Units and Rehabilitation Centers in Italy. Treatment was for 3 weeks using a newly ...developed integrated system with an enema continence catheter for transanal irrigation (Peristeen, Coloplast A/S Kokkedal Denmark).
To evaluate the effects of Peristeen Anal Irrigation on NBD and patient quality of life (QoL).
Italy.
Lesion level, ambulatory status and hand functionality were determined in all patients. NBD symptoms and QoL were evaluated before and after treatment, using a specific questionnaire. Statistical analysis was performed using McNemar Test and Sign Test.
Thirty-six patients were enrolled, and 32 patients completed the study. At the end of the treatment, 28.6% of patients reduced or eliminated their use of pharmaceuticals. Twenty-four patients became less dependent on their caregiver. There was a significant increase in patients' opinion of their intestinal functionality (P=0.001), QoL score (P=0.001) and their answers regarding their degree of satisfaction (P=0.001). A successful outcome was recorded for 68% of patients with fecal incontinence, and for 63% of patients with constipation.
Peristeen Anal Irrigation is a simple therapeutic method for managing NBD and improving QoL. It should be considered as the treatment of choice for NBD, playing a role in the neurogenic bowel analogous to that of intermittent clean catheterization in bladder treatment.
Five children with a neuroendocrine tumour (NET) of the appendix associated with a parasitic bowel infection are described, and the possibility of inflammation-triggered carcinogenesis is discussed. ...Schistosoma haematobium is linked primarily to bladder cancer but it has been reported in association with several other histotypes, including NETs of the gastrointestinal tract. Conversely, Enterobius vermicularis has not yet been claimed to participate in the onset of pre-cancerous conditions or tumours. The rare occurrence of contemporary appendiceal NETs and parasitic infection, raises the intriguing hypothesis of an inflammation-related carcinogenesis, although a cause–effect relationship cannot be established. Larger international series of childhood appendiceal NETs, which also include countries with higher prevalence of parasitic bowel infections, are needed to further clarify this possible cause–effect relationship.
Background/purpose
Aim of this study was to present a series of neonates and ex-preterm babies who underwent inguinal hernia repair focusing on complications and possible indication to perform ...routine contralateral groin exploration.
Methods
This is a retrospective study of a series of consecutive patients weighing less than 5 kg who underwent inguinal hernia repair between January 2007 and December 2012. Only the affected side was treated. Patients have been routinely followed up postoperatively. We resorted to available outpatients’ charts and admission notes to record demographic data, surgical details, complications and the occurrence of metachronous hernias. A questionnaire was administered to all patients’ relatives to confirm the long-term outcome.
Results
One hundred fifty-four patients were operated for a total of 184 herniotomies (88 right sided, 36 left sided and 30 bilateral). Median length of follow-up was 42 months (range 6 months–7.5 years). Thirteen patients (13/124 = 10.5 %) developed metachronous hernia that proved to be significantly more frequent in patients weighing less than 1,500 g at birth (
p
< 0.05). We observed 10 % of complications, including 2.7 % testicular atrophy and 4.5 % recurrence. Atrophy proved to occur more frequently in patients who experienced preoperative incarceration (
p
< 0.05). No other risk factors were identified.
Conclusions
The results of our series demonstrated that, though technically demanding, herniotomy in the neonate and ex-preterm is associated with a relatively low incidence of complications. Based on our results and in accordance with literature data, we do not advocate routine contralateral exploration in case of unilateral hernia but surgery to be performed only on the symptomatic side, as soon as possible after initial diagnosis. Very low birth weight patients should be followed with care in the early postoperative period due to the higher likelihood of developing a metachronous hernia.
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