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1
Chen, S. Y. "MANAGING THE DISPOSITION OF POTENTIALLY RADIOACTIVE SCRAP METAL". Health Physics 91, n. 5 (novembre 2006): 461–69. http://dx.doi.org/10.1097/01.hp.0000232854.47536.df.
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Luckett, Larry W. "Managing Potentially Radioactive Scrap Metal (NCRP Report No 141)". Health Physics 85, n. 6 (dicembre 2003): 760–61. http://dx.doi.org/10.1097/00004032-200312000-00023.
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Burgess, P. H. "Managing potentially radioactive scrap metal, NCRP Report No. 141. By NRCP, pp x + 224, 2002 (NCRP, Bethesda, MD), $45.00 ISBN 0-929600-74-6". British Journal of Radiology 77, n. 923 (novembre 2004): 977. http://dx.doi.org/10.1259/bjr.77.923.770977a.
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Nieves, L. A., e S. Y. Chen. "Risk and impact tradeoffs in radioactive scrap metal management". Journal of Hazardous Materials 44, n. 1 (novembre 1995): 37–51. http://dx.doi.org/10.1016/0304-3894(95)00048-y.
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Carriker, A. Wendell. "Recycled Scrap Metal and Soils/Debris with Low Radioactive Contents". International Journal of Radioactive Materials Transport 7, n. 1 (gennaio 1996): 27–32. http://dx.doi.org/10.1179/rmt.1996.7.1.27.
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Min, Byung Youn, Pyung Seob Song, Wang Kyu Choi, Chong Hun Jung, Won Zin Oh e Yong Kang. "Melting Decontamination of Radioactive Scrap Metal by Graphite Arc Melter". JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 41, n. 7 (2008): 607–11. http://dx.doi.org/10.1252/jcej.07we083.
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Yuracko, Katherine L., Stanton W. Hadley, Robert D. Perlack, Rafael G. Rivera e T. Randall Curlee. "A life cycle decision methodology for recycle of radioactive scrap metal". International Journal of Life Cycle Assessment 2, n. 4 (dicembre 1997): 223–28. http://dx.doi.org/10.1007/bf02978419.
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Furlan, Matteo, Andrea Rigoni, Sara Vanini, Gianni Zumerle, Paolo Checchia, Ludovico Cossutta, Giacomo Bettella et al. "Application of Muon Tomography to Detect Radioactive Sources Hidden in Scrap Metal Containers". IEEE Transactions on Nuclear Science 61, n. 4 (agosto 2014): 2204–9. http://dx.doi.org/10.1109/tns.2014.2321116.
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Solovev, D. B., e A. E. Merkusheva. "Use of Portal Monitors for Detection of Technogenic Radioactive Sources in Scrap Metal". IOP Conference Series: Materials Science and Engineering 262 (novembre 2017): 012198. http://dx.doi.org/10.1088/1757-899x/262/1/012198.
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BONOMI, G., D. CAMBIAGHI, L. DASSA, A. DONZELLA, M. SUBIETA, V. VILLA, A. ZENONI et al. "MUON TOMOGRAPHY AS A TOOL TO DETECT RADIOACTIVE SOURCE SHIELDING IN SCRAP METAL CONTAINERS". International Journal of Modern Physics: Conference Series 27 (gennaio 2014): 1460157. http://dx.doi.org/10.1142/s2010194514601574.
Testo completoAbstract (sommario):
Muon tomography was recently proposed as a tool to inspect large volumes with the purpose of recognizing high density materials immersed in lower density matrices. The MU-STEEL European project (RFCS-CT-2010-000033) studied the application of such a technique to detect radioactive source shielding in truck containers filled with scrap metals entering steel mill foundries. A description of the muon tomography technique, of the MU-STEEL project and of the obtained results will be presented.
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Makarenko, Andrey, Andrey Didyk, Roman Potapov e Aleksey Yakovenko. "Interlaboratory Comparisons in the Field of Radiation Control". ANRI, n. 3 (3 dicembre 2020): 33–41. http://dx.doi.org/10.37414/2075-1338-2020-102-3-33-41.
Testo completoAbstract (sommario):
The article discusses the features of the radiation control laboratories participation accredited in the Russian national accreditation system in interlaboratory comparisons. The participants results in the most relevant areas are presented - scrap metal radiation monitoring, multiparameter measurements on X-ray machines, radioactive radon monitoring. The participants results analysis was perfomed and typical errors that occur during measurements and processing of results were discussed.
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Carminati, Marco, Davide Di Vita, Giuseppe Morandi, Ilenia D’Adda e Carlo Fiorini. "Handheld Magnetic-Compliant Gamma-Ray Spectrometer for Environmental Monitoring and Scrap Metal Screening". Sensors 22, n. 4 (12 febbraio 2022): 1412. http://dx.doi.org/10.3390/s22041412.
Testo completoAbstract (sommario):
Spotting radioactive material in waste is of paramount importance for environment protection. This is particularly challenging when orphan sources are hidden in scrap metal that shields their activity from the traditional detectors in the portals scanning incoming trucks. In order to address this issue, we present a wireless and compact SiPM-based gamma spectrometer compatible with strong magnetic fields (0.1 T) to be installed in the bore of the lifting electromagnets to scan reduced volumes of metal and thus achieve higher sensitivity. The microcontroller-based instrument provides 11% energy resolution (at 662 keV), an energy range from 60 keV to 1.5 MeV, a max. count rate of 30 kcps, a weight <1 kg, and a power consumption <1 W. The results of its extensive characterization in the laboratory and its validation in the field, including operation in a scrap yard as well as on a drone, are reported.
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LORENZEN, Joachim. "Clearance of Radioactive Scrap Metal in Europe ; 17 Years of Experience of Free-Release at Studsvik in Sweden". Journal of the Atomic Energy Society of Japan / Atomic Energy Society of Japan 46, n. 9 (2004): 624–28. http://dx.doi.org/10.3327/jaesj.46.624.
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Clouvas, A., S. Xanthos, G. Takoudis, C. Potiriadis e J. Silva. "IN SITU GAMMA SPECTROMETRY MEASUREMENTS AND MONTE CARLO COMPUTATIONS FOR THE DETECTION OF RADIOACTIVE SOURCES IN SCRAP METAL". Health Physics 88, n. 2 (febbraio 2005): 154–62. http://dx.doi.org/10.1097/01.hp.0000144567.83125.00.
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Kvasnicka, J. "THE TOTAL MANAGEMENT OF NORM IN THE OFFSHORE PETROLEUM INDUSTRY". APPEA Journal 38, n. 2 (1998): 151. http://dx.doi.org/10.1071/aj97087.
Testo completoAbstract (sommario):
Naturally Occurring Radioactive Materials (NORMs) in the offshore petroleum industry are generally associated with the formation of scale in pipes and vessels. As scale and sludge contain radioactive isotopes of radium they are in the category of Low Specific Activity (LSA) NORMs. Handling of NORMs creates issues involving occupational health and safety, environmental protection and radioactive waste management and waste disposal. Barium(Radium)Sulfate scale is highly insoluble and can create serious production problems by clogging pipes and valves.The paper discusses the external gamma radiation monitoring at the external surfaces of well and oil production pipes which assists in establishing the scale thickness patterns in pipes and in identifying the optimum location of a scale inhibitor injection point.To minimise radiation doses received by workers special NORM handling Work Procedures and Instructions supported by radiation protection training need to be developed. If facility personnel are trained in radiation protection and Work Procedures and Instructions are adopted it is possible to effectively manage personal radiation exposures below the public limit of 1 millisievert per year. Under such conditions no personal radiation monitoring during routine operations is required and the assessment of routine annual external radiation doses may be carried out through yearly external gamma radiation surveys of of fshore petroleum production facilities.The NORM waste cannot be disposed of onshore within the same disposal sites used for general non-radioactive waste. In Australia only the NORM waste generated in Western Australia can be disposed of onshore in an official low level radioactive waste disposal facility. It is important that Governments of other States and Territories address the onshore NORM waste disposal option. Regulations should also address a screening method for scrap metal contaminated by NORMs to be released for smelting.
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Hong, Yong-Ho, Su-Ri Park, Sang-Wook Han e Byung-Jick Kim. "Smart Decontamination Device for Small-size Radioactive Scrap Metal Waste : Using Abrasion pin in Rotating Magnetic Field and Ultrasonic Wave Cleaner". Journal of the Nuclear Fuel Cycle and Waste Technology 12, n. 1 (30 marzo 2014): 79–88. http://dx.doi.org/10.7733/jnfcwt.2014.12.1.79.
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Yin, Allice Tan Mun, Shayfull Zamree Abd Rahim, Mohd Mustafa Al Bakri Abdullah, Marcin Nabialek, Abdellah El-hadj Abdellah, Allan Rennie, Muhammad Faheem Mohd Tahir e Aurel Mihail Titu. "Potential of New Sustainable Green Geopolymer Metal Composite (GGMC) Material as Mould Insert for Rapid Tooling (RT) in Injection Moulding Process". Materials 16, n. 4 (19 febbraio 2023): 1724. http://dx.doi.org/10.3390/ma16041724.
Testo completoAbstract (sommario):
The investigation of mould inserts in the injection moulding process using metal epoxy composite (MEC) with pure metal filler particles is gaining popularity among researchers. Therefore, to attain zero emissions, the idea of recycling metal waste from industries and workshops must be investigated (waste free) because metal recycling conserves natural resources while requiring less energy to manufacture new products than virgin raw materials would. The utilisation of metal scrap for rapid tooling (RT) in the injection moulding industry is a fascinating and potentially viable approach. On the other hand, epoxy that can endure high temperatures (>220 °C) is challenging to find and expensive. Meanwhile, industrial scrap from coal-fired power plants can be a precursor to creating geopolymer materials with desired physical and mechanical qualities for RT applications. One intriguing attribute of geopolymer is its ability to endure temperatures up to 1000 °C. Nonetheless, geopolymer has a higher compressive strength of 60–80 MPa (8700–11,600 psi) than epoxy (68.95 MPa) (10,000 psi). Aside from its low cost, geopolymer offers superior resilience to harsh environments and high compressive and flexural strength. This research aims to investigate the possibility of generating a new sustainable material by integrating several types of metals in green geopolymer metal composite (GGMC) mould inserts for RT in the injection moulding process. It is necessary to examine and investigate the optimal formulation of GGMC as mould inserts for RT in the injection moulding process. With less expensive and more ecologically friendly components, the GGMC is expected to be a superior choice as a mould insert for RT. This research substantially impacts environmental preservation, cost reduction, and maintaining and sustaining the metal waste management system. As a result of the lower cost of recycled metals, sectors such as mould-making and machining will profit the most.
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Stepkin, Yu I., M. I. Chubirko, M. K. Kuzmichev, O. V. Klepikov e S. A. Eprintsev. "Review of radiation incidents in the territory of the Voronezh region". Radiatsionnaya Gygiena = Radiation Hygiene 13, n. 3 (3 ottobre 2020): 131–35. http://dx.doi.org/10.21514/1998-426x-2020-13-3-131-135.
Testo completoAbstract (sommario):
The aim of the work was to characterize the radiation incidents that took place in the territory of the Voronezh region. Materials and methods. To prepare this article the stock data of the radiological laboratory of the Center for Hygiene and Epidemiology in the Voronezh Region for 2009-2018 was used. All measurements in the investigation of radiation incidents were carried out with the MKS-AT1117M dosimeter-radiometer which passed the state calibration. The equivalent dose rate of gamma radiation (μSv/h) was determined. Results. For the last 10 years, 8 radiation incidents were registered on the territory of the Voronezh region, which were related to domestic clocks - 4 (measurements according to citizens), the detection of orphan sources of ionizing findings - 2, scrap metal - 1 and a thermometer - 1 (during customs inspection). According to the classification of emergencies, the radiation incidents are local, i.e. do not go beyond the territory of the facility, according to the international scale of nuclear and radiological events, INES refer to the incident (anomalies) with the level 1 “minor problems with the safety of components, a radioactive source of low activity level”. All interactions in the investigation of radioactive incidents involving specialists from the radiological laboratory of the Center for Hygiene and Epidemiology in the Voronezh region with other services showed a good level of rapid response.
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Creamer, N. J., I. P. Mikheenko, K. Deplanche, P. Yong, J. Wood, K. Pollmann, S. Selenska-Pobell e Lynne E. Macaskie. "A Novel Hydrogenation and Hydrogenolysis Catalyst Using Palladized Biomass of Gram-negative and Gram-positive Bacteria". Advanced Materials Research 20-21 (luglio 2007): 603–6. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.603.
Testo completoAbstract (sommario):
Palladized biomass of typical Gram negative bacteria (Desulfovibrio desulfuricans and Escherichia coli) is well documented as a potentially useful catalyst for reduction of metallic species such as Cr(VI). This bionanocatalyst can be sourced from Pd-waste and scrap leachates via biocrystallization. A major industrial application of precious metal catalysts is in hydrogenation and hydrogenolysis reactions whereby, respectively, H is added across unsaturated bonds and halogen substituents can be removed from aromatic rings. Gram positive bacteria have not been evaluated previously as potential supported Pd-bionanocatalysts. We compare the activity of ‘Bio-Pd(0)’ supported on the fundamentally different Gram negative (Desulfovibrio) and Gram positive (Bacillus) bacterial surfaces, and evaluate the activity of the two types of ‘Bio-Pd(0)‘ in a standard reference reaction, the hydrogenation of itaconic acid, against a commercially available catalyst (5% Pd on carbon). The results show that the bionanocatalysts have a similar activity to the commercial material and biomanufacturing from waste sources may be an economic alternative to conventional processing for catalyst production as precious metal prices continue to rise.
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Lauermannová, Anna-Marie, Iva Paterová, Jan Patera, Kryštof Skrbek, Ondřej Jankovský e Vilém Bartůněk. "Hydrotalcites in Construction Materials". Applied Sciences 10, n. 22 (11 novembre 2020): 7989. http://dx.doi.org/10.3390/app10227989.
Testo completoAbstract (sommario):
Hydrotalcites are layered double hydroxides displaying a variety of stoichiometry caused by the different arrangement of the stacking of the layers, ordering of the metal cations, as well as the arrangement of anions and water molecules, in the interlayer galleries. The compounds of the hydrotalcite group show a wide range of the possible applications due to their specific properties, such as their large surface area, ion exchange ability, the insolubility in water and most of the organic sorbents, and others. Affordability, wide possibilities of manufacturing, and presence of sufficient natural deposits make hydrotalcites potentially very useful for the construction industry, as either a building material itself or an additive in mortars, concrete or in polymers composites used in constructions. Similar possible application of such material is in leakage control in a radioactive waste repository. The effect of use of these materials for ion exchange, anti-corrosion protection, radioactive ions containment, and similar purposes in building materials is examined in this review.
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Wicks, George G., Alexander R. Lodding e Martin A. Molecke. "Aqueous Alteration of Nuclear Waste Glasses and Metal Package Components". MRS Bulletin 18, n. 9 (settembre 1993): 32–39. http://dx.doi.org/10.1557/s0883769400038008.
Testo completoAbstract (sommario):
The United States is at an important crossroads in its management of high-level radioactive waste (HLW). It is presently in the process of changing over from a strategy that was developed during World War II, which involves storing HLW in a relatively mobile liquid form, to a strategy of the 1990s, which involves removing and isolating potentially harmful radionuclides and immobilizing them into solid and inert forms, more specifically, borosilicate glass. The resulting waste glass products will then be permanently disposed of by deep burial, within stable geologic formations, where they become one element of a multibarrier waste-isolation system. This barrier system is designed to retain radionuclides so they can be permanently isolated from the public and from the accessible environment. Important contributing factors to the success of this strategy include the excellent stability and technical performance of waste glass forms and the ability of the glass, as well as waste package materials, to retain radionuclides even when exposed to potential leachants within a repository environment.
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Neuhausen, Jörg. "Radionuclide Chemistry in Nuclear Facilities Based on Heavy Liquid Metal Coolants: Past, Present and Future". CHIMIA International Journal for Chemistry 74, n. 12 (23 dicembre 2020): 976–83. http://dx.doi.org/10.2533/chimia.2020.976.
Testo completoAbstract (sommario):
Heavy liquid metals such as lead and lead bismuth eutectic (LBE) are considered as spallation target material for next-generation neutron sources and as coolant of fast spectrum nuclear reactors that are developed to facilitate more efficient use of nuclear fuel as well as transmutation of long-lived nuclear waste. During the operation of such facilities, the heavy liquid metal will be activated by nuclear reactions. Additionally, fission product radionuclides may be introduced into the liquid metal from leaking fuel pins or by fission of the target nuclei in spallation. The chemical behaviour of these radioactive contaminants in the liquid metal – especially their immediate volatilization or volatilization of formed secondary compounds – may affect the safety of such facilities. The present article summarizes the activities of PSI's Laboratory of Radiochemistry towards a better understanding of the chemistry of potentially hazardous radionuclides in LBE and discusses aspects that need to be addressed in future to support the licensing of heavy liquid metal-based nuclear facilities.
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Godswill, Awuchi Chinaza, Awuchi Chibueze Gospel, Amagwula Ikechukwu Otuosorochi e Igwe Victory Somtochukwu. "Industrial And Community Waste Management: Global Perspective". American Journal of Physical Sciences 1, n. 1 (18 febbraio 2020): 1–16. http://dx.doi.org/10.47604/ajps.1043.
Testo completoAbstract (sommario):
Purpose:The review focused on the management of industrial and communal wastes. Industrial and communal waste management practices are not uniform among countries; urban and rural areas, residential, and industrial sectors, all take different approaches.
Methodology: Industrial wastes can be classified on basis of their characteristics; Waste in dissolved and pollutant is in liquid form, e.g. dairy industry; Waste in solid form, but a number of pollutants within are in the liquid or fluid form, e.g. washing of minerals or crockery industry or coal.
Results: Industrial waste is produced as a result of industrial activities, including materials rendered useless during manufacturing process such as that of food and chemical industries, mills, factories, and mining operations. Dirt and gravel, concrete and masonry, solvents, chemicals, scrap lumber, scrap metal, oil, etc. are types of industrial waste. Industrial or community waste may be liquid, solid, or gaseous. It may be absolutely hazardous, mirror entry, or non-hazardous waste. Hazardous waste can be toxic, ignitable, corrosive, radioactive, or reactive. Industrial waste may pollute the soil, the air, or nearby water bodies, ending up in the sea.
Unique contribution to theory, practice and policy: Waste management is important component in a business' ability to maintain the ISO14001 accreditation. The ISO14001 standard encourages companies to ensure green environment and improve their environmental efficiencies every year by eliminating waste through the resource recovery practices. The principles of waste management puts some factors into consideration such as waste hierarchy, life-cycle of a product, resource efficiency, and polluter-pays principle. Common waste disposal and management methods include incineration, landfill, recycling, re-use, pyrolysis, resource recovery, composting, among others. An important method of waste management in industries and communities is the prevention of waste materials being created, better known as waste reduction. The waste management industry has adopted new technologies such as Radio Frequency Identification (RFID) tags, GPS, etc., which enable the collection of better quality data without the using estimation or manual data entry.
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Rotariu, Traian, Daniela Pulpea, Gabriela Toader, Edina Rusen, Aurel Diacon, Valentina Neculae e John Liggat. "Peelable Nanocomposite Coatings: “Eco-Friendly” Tools for the Safe Removal of Radiopharmaceutical Spills or Accidental Contamination of Surfaces in General-Purpose Radioisotope Laboratories". Pharmaceutics 14, n. 11 (1 novembre 2022): 2360. http://dx.doi.org/10.3390/pharmaceutics14112360.
Testo completoAbstract (sommario):
Radioactive materials are potentially harmful due to the radiation emitted by radionuclides and the risk of radioactive contamination. Despite strict compliance with safety protocols, contamination with radioactive materials is still possible. This paper describes innovative and inexpensive formulations that can be employed as ‘eco-friendly’ tools for the safe decontamination of radiopharmaceuticals spills or other accidental radioactive contamination of the surfaces arising from general-purpose radioisotope handling facilities (radiopharmaceutical laboratories, hospitals, research laboratories, etc.). These new peelable nanocomposite coatings are obtained from water-based, non-toxic, polymeric blends containing readily biodegradable components, which do not damage the substrate on which they are applied while also displaying efficient binding and removal of the contaminants from the targeted surfaces. The properties of the film-forming decontamination solutions were assessed using rheological measurements and evaporation rate tests, while the resulting strippable coatings were subjected to Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile tests. Radionuclide decontamination tests were performed on various types of surfaces encountered in radioisotope workspaces (concrete, painted metal, ceramic tiles, linoleum, epoxy resin cover). Thus, it was shown that they possess remarkable properties (thermal and mechanical resistance which permits facile removal through peeling) and that their capacity to entrap and remove beta and alpha particle emitters depends on the constituents of the decontaminating formulation, but more importantly, on the type of surface tested. Except for the cement surface (which was particularly porous), at which the decontamination level ranged between approximately 44% and 89%, for all the other investigated surfaces, a decontamination efficiency ranging from 80.6% to 96.5% was achieved.
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Vergara, Vernieda B., e John F. Kalinich. "Nutraceuticals as Potential Radionuclide Decorporation Agents". Nutrients 13, n. 8 (25 luglio 2021): 2545. http://dx.doi.org/10.3390/nu13082545.
Testo completoAbstract (sommario):
Exposure of individuals to radioactive material as a result of ingestion of contaminated food and water is an increasing public health concern. Unfortunately, there are limited treatment modalities for dealing with these types of potentially toxic exposures. Recent research suggests that many plant-based nutraceuticals may possess metal-binding properties. This preliminary study investigated the ability of genistein, curcumin, quercetin, and lentinan to bind metals considered internal contamination risks, namely cesium, uranium, cobalt, and strontium, in a variety of matrices. The efficacy of these nutraceuticals in protecting cultured cells from metal-induced toxicity was also explored. Results showed that none of the compounds bound cesium or strontium. However, genistein, curcumin, and quercetin could bind uranium. Curcumin and quercetin also bound cobalt and could also protect cultured cells from metal-induced cytotoxicity. Lentinan did not bind any of the metals tested. Metal binding was also pH dependent, with no binding observed at lower pH values. This project showed that nutraceuticals could function as chelators for metals considered internal radionuclide contamination hazards. Further investigations are required in order to determine whether these compounds will become a new nontoxic arsenal of pharmaceutical compounds with which to treat radionuclide contamination.
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Lusa, Merja, e Malin Bomberg. "Microbial Community Composition Correlates with Metal Sorption in an Ombrotrophic Boreal Bog: Implications for Radionuclide Retention". Soil Systems 5, n. 1 (19 marzo 2021): 19. http://dx.doi.org/10.3390/soilsystems5010019.
Testo completoAbstract (sommario):
Microbial communities throughout the 6.5 m depth profile of a boreal ombrotrophic bog were characterized using amplicon sequencing of archaeal, fungal, and bacterial marker genes. Microbial populations and their relationship to oxic and anoxic batch sorption of radionuclides (using radioactive tracers of I, Se, Cs, Ni, and Ag) and the prevailing metal concentrations in the natural bog was investigated. The majority of the detected archaea belonged to the Crenarchaeota, Halobacterota, and Thermoplasmatota, whereas the fungal communities consisted of Ascomycota, Basidiomycota, and unclassified fungi. The bacterial communities consisted mostly of Acidobacteriota, Proteobacteria, and Chloroflexi. The occurrence of several microbial genera were found to statistically significantly correlate with metal concentrations as well as with Se, Cs, I, and Ag batch sorption data. We suggest that the metal concentrations of peat, gyttja, and clay layers affect the composition of the microbial populations in these nutrient-low conditions and that particularly parts of the bacterial and archaeal communities tolerate high concentrations of potentially toxic metals and may concurrently contribute to the total retention of metals and radionuclides in this ombrotrophic environment. In addition, the varying metal concentrations together with chemical, mineralogical, and physical factors may contribute to the shape of the total archaeal and bacterial populations and most probably shifts the populations for more metal resistant genera.
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Rakos, Jason, Karen Gonzalez, Vivian Flaum, Dustyn Weber e Cory Rusinek. "Detection of Pertechnetate Using Square Wave Anodic Stripping Voltammetry on Carbon Electrodes". ECS Meeting Abstracts MA2022-02, n. 58 (9 ottobre 2022): 2195. http://dx.doi.org/10.1149/ma2022-02582195mtgabs.
Testo completoAbstract (sommario):
Technetium-99 (Tc-99) is a primary fission product of U-235, U-233, and Pu-239 and is a major constituent of radioactive waste. Tc-99 is commonly found as pertechnetate (TcO4 -), an anion that does not readily adsorb to natural sediment and is extremely mobile in environmental water systems. With concerns that radioactive waste may be leaking from sub-surface storage tanks and potentially reaching groundwater, developing detection methods for TcO4 - is important. Square wave anodic stripping voltammetry (SWASV) is a simple electrochemical technique that has yet to be investigated for pertechnetate due to the high potential required to form solid TcO2. In this work, we use SWASV with a variety of carbon electrodes to determine the optimal conditions for the detection of TcO4 - in a variety of solutions including acidic, basic and neutral pH. Carbon electrodes such as glassy carbon, boron-doped diamond, and nitrogen-doped tetrahedral amorphous carbon were examined. Carbon electrodes are ideal for the detection of pertechnetate due to their robust nature, low background current, and wide windows when compared to metal electrodes. Control studies included optimization of the deposition potential and time. In addition, calibration curves were created for each solution’s optimized parameters. Several analytical figures of merit such as the sensitivity, limit of detection, and limit of quantification were determined. This work expands upon the use of carbon electrodes for trace detection of environmentally relevant analytes.
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David, Martin, e Florian Koch. "“Smart Is Not Smart Enough!” Anticipating Critical Raw Material Use in Smart City Concepts: The Example of Smart Grids". Sustainability 11, n. 16 (16 agosto 2019): 4422. http://dx.doi.org/10.3390/su11164422.
Testo completoAbstract (sommario):
Globally emerging smart city concepts aim to make resource production and allocation in urban areas more efficient, and thus more sustainable through new sociotechnical innovations such as smart grids, smart meters, or solar panels. While recent critiques of smart cities have focused on data security, surveillance, or the influence of corporations on urban development, especially with regard to intelligent communication technologies (ICT), issues related to the material basis of smart city technologies and the interlinked resource problems have largely been ignored in the scholarly literature and in urban planning. Such problems pertain to the provision and recovery of critical raw materials (CRM) from anthropogenic sources like scrap metal repositories, which have been intensely studied during the last few years. To address this gap in the urban planning literature, we link urban planning literatures on smart cities with literatures on CRM mining and recovery from scrap metals. We find that underestimating problems related to resource provision and recovery might lead to management and governance challenges in emerging smart cities, which also entail ethical issues. To illustrate these problems, we refer to the smart city energy domain and explore the smart city-CRM-energy nexus from the perspectives of the respective literatures. We show that CRMs are an important foundation for smart city energy applications such as energy production, energy distribution, and energy allocation. Given current trends in smart city emergence, smart city concepts may potentially foster primary extraction of CRMs, which is linked to considerable environmental and health issues. While the problems associated with primary mining have been well-explored in the literature, we also seek to shed light on the potential substitution and recovery of CRMs from anthropogenic raw material deposits as represented by installed digital smart city infrastructures. Our central finding is that the current smart city literature and contemporary urban planning do not address these issues. This leads to the paradox that smart city concepts are supporting the CRM dependencies that they should actually be seeking to overcome. Discussion on this emerging issue between academics and practitioners has nevertheless not taken place. We address these issues and make recommendations.
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Podlech, Carolin, Nicole Matschiavelli, Markus Peltz, Sindy Kluge, Thuro Arnold, Andrea Cherkouk, Artur Meleshyn, Georg Grathoff e Laurence N. Warr. "Bentonite Alteration in Batch Reactor Experiments with and without Organic Supplements: Implications for the Disposal of Radioactive Waste". Minerals 11, n. 9 (27 agosto 2021): 932. http://dx.doi.org/10.3390/min11090932.
Testo completoAbstract (sommario):
Bentonite is currently proposed as a potential backfill material for sealing high-level radioactive waste in underground repositories due to its low hydraulic conductivity, self-sealing ability and high adsorption capability. However, saline pore waters, high temperatures and the influence of microbes may cause mineralogical changes and affect the long-term performance of the bentonite barrier system. In this study, long-term static batch experiments were carried out at 25 °C and 90 °C for one and two years using two different industrial bentonites (SD80 from Greece, B36 from Slovakia) and two types of aqueous solutions, which simulated (a) Opalinus clay pore water with a salinity of 19 g·L−1, and (b) diluted cap rock solution with a salinity of 155 g·L−1. The bentonites were prepared with and without organic substrates to study the microbial community and their potential influence on bentonite mineralogy. Smectite alteration was dominated by metal ion substitutions, changes in layer charge and delamination during water–clay interaction. The degree of smectite alteration and changes in the microbial diversity depended largely on the respective bentonite and the experimental conditions. Thus, the low charged SD80 with 17% tetrahedral charge showed nearly no structural change in either of the aqueous solutions, whereas B36 as a medium charged smectite with 56% tetrahedral charge became more beidellitic with increasing temperature when reacted in the diluted cap rock solution. Based on these experiments, the alteration of the smectite is mainly attributed to the nature of the bentonite, pore water chemistry and temperature. A significant microbial influence on the here analyzed parameters was not observed within the two years of experimentation. However, as the detected genera are known to potentially influence geochemical processes, microbial-driven alteration occurring over longer time periods cannot be ruled out if organic nutrients are available at appropriate concentrations.
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Saatchi, Katayoun, François Bénard, Navjit Hundal, Joshua Grimes, Sergey Shcherbinin, Maral Pourghiasian, Donald E. Brooks, Anna Celler e Urs O. Häfeli. "Preclinical PET Imaging and Toxicity Study of a 68Ga-Functionalized Polymeric Cardiac Blood Pool Agent". Pharmaceutics 15, n. 3 (25 febbraio 2023): 767. http://dx.doi.org/10.3390/pharmaceutics15030767.
Testo completoAbstract (sommario):
Cardiac blood pool imaging is currently performed almost exclusively with 99mTc-based compounds and SPECT/CT imaging. Using a generator-based PET radioisotope has a few advantages, including not needing nuclear reactors to produce it, obtaining better resolution in humans, and potentially reducing the radiation dose to the patient. When the shortlived radioisotope 68Ga is used, it can be applied repeatedly on the same day—for example, for the detection of bleeding. Our objective was to prepare and evaluate a long-circulating polymer functionalized with gallium for its biodistribution, toxicity, and dosimetric properties. A 500 kDa hyperbranched polyglycerol was conjugated to the chelator NOTA and radiolabeled rapidly at room temperature with 68Ga. It was then injected intravenously into a rat, and gated imaging allowed us to easily observe wall motion and cardiac contractility, confirming the suitability of this radiopharmaceutical for cardiac blood pool imaging. Internal radiation dose calculations showed that the radiation doses that patients would receive from the PET agent would be 2.5× lower than those from the 99mTc agent. A complete 14-day toxicology study in rats concluded that there were no gross pathology findings, changes in body or organ weights, or histopathological events. This radioactive-metal-functionalized polymer might be a suitable non-toxic agent to advance for clinical application.
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Fryirs, Kirstie, Ian Snape e Nadia Babicka. "The type and spatial distribution of past waste at the abandoned Wilkes Station, East Antarctica". Polar Record 49, n. 4 (7 febbraio 2013): 328–47. http://dx.doi.org/10.1017/s0032247412000721.
Testo completoAbstract (sommario):
ABSTRACTLegacy waste is a significant problem in Antarctica. This is particularly the case where waste generated on stations prior to the 1980s was incinerated, placed in landfill sites or disposed of at sea. Although several Australian Antarctic Division (AAD) reports from the 1980s recognise that there are contaminated sites at the abandoned Wilkes Station, there has been no systematic attempt to classify the waste or define the spatial scale of the problem, making development of strategic and systematic clean-up or preservation programmes difficult. This article reports on a project to classify the waste remaining on Clark Peninsula using categories listed in Annex III, Article 2 of the Madrid Protocol (1991). 536 sites with one or more waste items have been identified in nine categories that are based on the degree of waste hazard, recyclability, heritage value and waste management potential. Fuel drums, petroleum hydrocarbons waste and contaminated sediment occur at 38% of the sites. This waste includes around 1020 partially full fuel drums. Heritage items that illustrate expedition life at Wilkes occur at about 10% of the sites. Solid, non-combustible waste, including scrap metal, copper wire and pipe, and steel mechanical parts, occurs at 25% of the sites. Potentially hazardous or harmful waste including electrical batteries, plastics including fuel bladders, food remains, treated timber and containers containing persistent compounds occur at 28% of sites. Although hazardous substances, such as caustic soda, explosives and asbestos, occur at only 9% of the sites, these items represent significant contamination and heath issues for the sites and for visiting explorers. Any future clean-up operations will require more than just the physical removal of waste. Preservation, removal and treatment of various types of waste from Wilkes will be required as part of a multi-year, multi-strategy approach.
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Dua, Kulwinder S. "Expanding Role of Self Expanding Esophageal Stents". Journal of Digestive Endoscopy 02, n. 01 (gennaio 2011): 009–14. http://dx.doi.org/10.1055/s-0039-1700253.
Testo completoAbstract (sommario):
ABSTRACTEsophageal cancer is often diagnosed at a late stage and hence carries a poor prognosis with an overall 5-year survival rate of 10% to 15%. Therefore, palliative treatment primarily aimed at the relieving dysphagia is the only available option. Endoscopic placement of self expanding metal stents (SEMS) has become a widely used method for palliation offering prompt relief of dysphagia and numerous reports have shown it to be safe and effective. Secondary to tissue in-growth into the uncovered segments of the stent, SEMS cannot be removed and hence are not approved for benign indications. With the advent of the removable self expanding plastic stents, the indications for esophageal stent insertion have expanded to as bridge to surgery for patients undergoing neoadjuvant chemotherapy, for refractory benign esophageal strictures, for non- malignant esophageal perforations, leaks and fistulae, and even for variceal hemorrhage. Newer fully covered SEMS that are potentially removable are also being tried for benign indications but await FDA clearance. Similarly biodegradeable stents for benign disorders and radioactive or drug-eluding stents for malignant disease are hoped to improve the management of esophageal diseases. The purpose of this article is to review the expanding role of self expanding stents in the management of esophageal disorders other than palliating malignant dysphagia and fistulae.(J Dig Endos 2011;2(1):9-14)
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Standing, Rhys David, Christian James Laycock, Richard M. Dinsdale, Gareth Lloyd e Alan J. Guwy. "The Use of Zinc-Bromine Battery Technology to Remove and Recover Zinc from Scrap and Waste Steel Resources". ECS Meeting Abstracts MA2022-02, n. 4 (9 ottobre 2022): 531. http://dx.doi.org/10.1149/ma2022-024531mtgabs.
Testo completoAbstract (sommario):
ZBBs have a high open circuit voltage (1.82 V), a high theoretical energy (> 400 W h-1 kg-1) and high demonstrated power densities (> 100 mW cm-2). Typically, ZBBs adopt a redox flow design involving the use of a Nafion membrane to separate aqueous zinc bromide anolyte and catholyte solutions [1]. In this study, the use of a membrane-free non-flow design was investigated for the purposes of recovering zinc from scrap and waste steel resources [2]. The rationale for this work stems from the greenhouse gas emissions produced by the iron and steel industry, which accounts for between 4-7 % of the anthropogenic CO2 emissions globally [3]. Blast furnace technology is likely to account for most stainless steel production in the coming decades, and therefore a transition to low-carbon and green steel production will require increased steel recycling rates and significantly improved waste and scrap management. To the best of our knowledge, this is the first time a zinc-bromine battery has been investigated for the recovery of materials rather than energy storage. Galvanization of steel is required to prevent rusting and degradation and involves coating the surface of steel in a protective layer of zinc. Galvanization processes account for over 50 % of global zinc consumption and by 2050 the demand for zinc will be 2.7 times greater than that of 2012 [4]. In order to enable recycling of scrap steel directly into blast furnaces, zinc is removed and recovered via mineral acid leaching. This method of recovery has a high zinc extraction efficiency but creates problematic waste streams and has poor energetic efficiency. In this work, the use of a membrane-free zinc-bromine battery has been studied for the purposes of extracting zinc from steel substrates and subsequently re-electroplating onto a conventional carbon foam electrode. The electrical performance of the cell was characterised by charge-discharge profiles and I-V curves. Zinc removal and recovery onto electrodes was characterised using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The work successfully demonstrates that ZBB technology could enable efficient and clean recovery of zinc from metal and waste substrates including scrap steel, slurries generated from basic oxygen steelmaking processes, and secondary vent dust from the primary steelmaking off gas streams. The cell studied in this work enabled dipping of zinc-containing steel substrates directly into the electrolyte solution without disassembly of the battery housing. In addition, the design involved the use of low-cost materials and reagents and potentially offers low balance-of-plant costs. The results show that zinc could be removed from steel surfaces during cell discharge with greater than 99.9 % yield. The Figure shows the extracted zinc could subsequently be re-electroplated onto a standard carbon foam electrode upon re-charging the cell. When a 0.5 V cut-off voltage was used upon discharge, the zinc was recovered selectively from the steel (see Fig. (a)); the surface elemental composition of the carbon electrode measured by EDS after charging was: carbon (26.79 wt%), oxygen (18.06 wt%), zinc (30.03 wt%) and bromine (25.11 wt%). Using a lower cut-off voltage (0.2 V) resulted in the co-extraction of iron from the substrate as well as zinc (see Fig. (b)); in this case, the elemental composition of the carbon electrode after charging was: carbon (27.53 wt%), oxygen (22.65 wt%), iron (4.72 wt%), zinc (24.44 wt%) and bromine (20.65 wt%). Provided a cut-off voltage of no less than 0.5 V was used for discharging, high purity zinc was recovered, and the cell showed good initial durability, with 30 cycles of charge-discharge demonstrated in this work. [1] S. Suresh, M. Ulaganathan, N. Venkatesan, P. Periasamy, P. Ragupathy, High performance zinc-bromine redox flow batteries: Role of various carbon felts and cell configurations. J. Energy Storage, 2018. 20: pp. 134-139. [2] S. Biswas, A. Senju, R. Mohr, T. Hodson, N. Karthikeyan, K. Knehr, A.G. Hsieh, X. Yang, B.E. Koel, D.A. Steingart, Minimal architecture zinc-bromine battery for low-cost electrochemical storage. Energy Environ. Sci., 2017. 10: pp. 114-120. [3] Iron and Steel Technology Roadmap: Towards More Sustainable Steelmaking, Energy Technology Perspectives, International Energy Agency, IEA Publications, Paris, 2020. https://www.iea.org/reports/iron-and-steel-technology-roadmap [accessed 12 April 2022]. [4] K.S. Ng, I. Head, G.C. Premier, K. Scott. E. Yu, J. Lloyd, J. Sadhukhan. A multilevel sustainability analysis of zinc recovery from wastes. Resour. Conserv. Recycl., 2016. 113: pp. 88-105. Figure. SEM images showing the carbon foam zinc electrodes after charging the cell. (a) is an electrode when a discharge cut-off voltage of 0.5 V was used, (b) is an electrode when a discharge cut-off voltage of 0.2 V was used. Figure 1
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Rajkovic, Milos, e Dragan Toskovic. "Investigation of the possibilities of phosphogypsum application for building partitioning Walls - elements of a prefabricated house". Acta Periodica Technologica, n. 33 (2002): 71–92. http://dx.doi.org/10.2298/apt0233071r.
Testo completoAbstract (sommario):
Phosphogypsum is a waste product in the manufacture of phosphoric acid from phosphorite and sulphuric acid by so-called "wet process" and represents a refuse that is as such simply thrown away. Phosphogypsum which is produced by "dihydrating procedure" contains not only various impurties but also radionuclides, which limits its construction use. Performed testings point to the complexity of phosphogypsum structure and composition while the electron microscope's pictures showed its different crystal composition compared to the natural gypsum. The calcined and refined phosphogypsum can be used for partition walls manufacture. To avoid the danger of the possible presence of radionuclides it is better to use the mixture of natural gypsum and phosphogypsum for this purpose. Substantial saving of materials and economic effect can be achieved in this way. The analyse performed in this work have shown significant presence of radionuclides in phosphogypsum. Gammaspectrometric measurements of radioactivity have determined substantial radioactivity of phosphogypsum. Using the maximum tolerated level values that are legally accepted, as well as equations to calculate indexes of tolerated radionuclide presence, an index of 2.23 has been determined for interiors and 1.13 for exteriors, i.e. 0.64 in case of roads. On the basis of the maximum tolerated level of radioactive building materials contamination (< 1), forbiden is the use of phosphogypsum in interiors, allowed (? 1) in exteriors and roads. The tests of heavy metal components in phosphogypsum have proved their presence in the amounts potentially producing consequences if present in closed spaces. That is conditioned by the phosphogypsum quantity, as well as by the area of space partitioned.
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Bond, A. E., K. E. Thatcher e S. Norris. "Multi-scale gas transport modelling for the EC FORGE project". Mineralogical Magazine 79, n. 6 (novembre 2015): 1251–63. http://dx.doi.org/10.1180/minmag.2015.079.7.01.
Testo completoAbstract (sommario):
AbstractThe generation and migration of gas within and around proposed radioactive waste disposal facilities is potentially a safety critical process. A safety case for a facility that generates significant quantities of gas (e.g. through metal corrosion or radiolysis) will require demonstration that gas migration around and away from the waste is sufficiently understood and will not breach the safety case for the facility. Models can be used to understand the likely hydraulic evolution of such a disposal facility, but the models need to consider processes over a range of scales. A whole repository may extend over kilometres, with individual disposal cells at the scale of tens of metres and features which provide pathways for gas migration on a centimetre scale. All of these features may be significant from a safety perspective and capturing the impact of all of these features in a single model is a significant challenge.This paper presents an approach to tackling this multi-scale problem, which allows the whole repository to be modelled in a computationally efficient manner. The approach involves identifying areas within the modelled domain that show very similar behaviour, and representing these areas with sub-models, so that small-scale features are retained, but computational overhead is decreased by using the results in more than one location in the model domain. The approach allowed a model of a whole repository to be run on a single processor core, whilst maintaining the small-scale features of the system. The model results were compared against more conventional upscaling techniques and show the advantage of a more detailed representation of small-scale features. The model results reflect the conceptual understanding of how gas would migrate in a repository.
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Marland, Pippa Jane. "“Heaps of scrap metal and defunct machinery”: Assemblages, Ethics and Affect in W. G. Sebald’s Orford Ness // "Montones de chatarra y maquinaria obsoleta”: Ensamblajes, ética y afecto en el Orford Ness de W. G. Sebald". Ecozon@: European Journal of Literature, Culture and Environment 5, n. 2 (22 settembre 2014): 123–39. http://dx.doi.org/10.37536/ecozona.2014.5.2.617.
Testo completoAbstract (sommario):
This essay explores aspects of the ‘material turn’ in contemporary thought and their incorporation into the emergent field of material ecocriticism. I tentatively suggest that although the ‘new materialisms’ have provided both posthumanism and ecocriticism with invaluable tools for decentring the ‘human’ and disrupting anthropocentric world views, they have at times deflected attention too far from the specificity of the human animal. I argue that while material ecocriticism has fruitfully engaged with concepts of material interrelatedness and its effects on bodies and environments, and begun to explore the ethical implications of such entanglements, it has, as yet, been less forthcoming on the subject of affect. Drawing on recent formulations of ‘affect theory’ that characterise affect as operating within the context of material immersion and processes of becoming, as well as being potentially instrumental in the recalibration of ethical positions, I contend that there are significant parallels with material ecocriticism that signal the potential for further exploration of what we might call material affect.These arguments are explored further through a reading of W.G. Sebald’s account in The Rings of Saturn of a visit to the defunct military weapons-testing base at Orford Ness. I highlight Sebald’s evocation of the darkly disturbing, vitally affective power of the landscape’s assemblage of “scrap metal and defunct machinery” (237), which triggers a response in the narrator-figure that is integrally bound up with aspects of memory, conscience, and, ultimately, ethics. In the light of this reading, I argue for the need for an ongoing humanism within posthumanist ecocriticism that combines an understanding of our immersion in and dependence upon the nonhuman world with a continuing and specific investigation of the human animal and its affective sensorium, focused in particular on the way in which affect may play into the generation of ethical aspiration.ResumenEste ensayo explora aspectos del “giro materialista” en el pensamiento actual y su incorporación en el campo emergente de la ecocrítica materialista. Sugiero provisionalmente que aunque los “nuevos materialismos” han proporcionado tanto al posthumanismo como a la ecocrítica herramientas inestimables para descentrar “lo humano” y alterar las visiones antropocéntricas del mundo, a veces han desviado la atención demasiado lejos de la especificidad del animal humano. Sostengo que mientras que la ecocrítica materialista se ha dedicado fructíferamente a conceptos de interrelación material y sus efectos en los cuerpos y entornos, y ha empezado a explicar las implicaciones éticas de dichas relaciones, ha sido menos cooperativa, de momento, en el tema del afecto. Recurriendo a las formulaciones recientes de la “teoría del afecto” que caracterizan éste en la medida que funciona dentro del contexto de la inmersión materialista y de los procesos de llegar a ser, así como siendo potencialmente fundamental en la re-calibración de posiciones éticas, afirmo que existen paralelismos significativos con la ecocrítica materialista que señalan la posibilidad de una exploración más a fondo de lo que podríamos llamar afecto materialista. Estos argumentos es exploran en detalle por medio de una lectura de la narración de W.G. Sebald en The Rings of Saturn sobre una visita a una obsoleta base militar de pruebas de armamento en Orford Ness. Destaco la evocación de Sebald del poder del paisaje oscuramente perturbador y vitalmente afectivo de la colección de “restos de chatarra y maquinaria obsoleta” (237), que desencadena una respuesta en la figura del narrador que está integralmente unida con aspectos de la memoria, la conciencia y, por último, la ética. En base a esta lectura, defiendo la necesidad de un humanismo en desarrollo dentro de la ecocrítica posthumanista que combina la comprensión de nuestra inmersión en y dependencia del mundo no humano con una investigación continua y específica del animal humano y su sensorium afectivo, centrándose en particular en la manera en que el afecto puede influir en la creación de aspiración ética.
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Morelová, Nikoleta, Kathy Dardenne, Nicolas Finck, Frank Heberling, Volker Metz, Dieter Schild, Horst Geckeis e Nikitas Diomidis. "Anaerobic corrosion of carbon steel in compacted bentonite exposed to natural Opalinus clay porewater: Bentonite alteration study". Safety of Nuclear Waste Disposal 1 (10 novembre 2021): 103–4. http://dx.doi.org/10.5194/sand-1-103-2021.
Testo completoAbstract (sommario):
Abstract. Carbon steel is a potential canister material for the disposal of high-level radioactive waste in deep geological repositories in clays and clay rocks. Bentonite is considered as a potential backfill material for those multi-barrier systems. To predict the long-term performance and for safety assessment the knowledge of canister corrosion behavior is important. The corrosion products formed and mineralogically altered bentonite at the canister/bentonite interface can potentially provide an additional barrier against radionuclide migration. In-situ corrosion experiments were performed at the Mont Terri underground research laboratory. Coupons of carbon steel were embedded in Volclay MX-80 bentonite with controlled densities, installed in a borehole under simulated repository and anaerobic conditions and exposed to natural Opalinus clay porewater for a period up to 5.5 years (Smart et al., 2017). In the present study, the bentonite layer at the canister/bentonite interface was characterized by complementary microscopic and spectroscopic techniques (XPS, SEM-EDX, µXANES) under anoxic conditions. The interface revealed reddish-brown staining up to 2 mm depth into the bentonite in the zone adjacent to the steel in all three obtained samples. The XPS analysis revealed formation of sulfides at the interface consisting of iron and other trace metals present in the steel. The SEM-EDX analyses of the interface (embedded cross-cut with steel removed) showed different degrees of calcium enrichment in the bentonite adjacent to the metal for various samples. The µXRF analysis performed on the bentonite at the interface showed a scarce or distinct calcium-enriched rim up to 100 µm into the bentonite and iron-enriched rim depending on the sample (one sample in Fig. 1), while µXANES analysis revealed formation of iron silicate compounds in the reacted reddish-brown zone. The iron appears to displace calcium from the interlayer sites in montmorillonite. The calcium then precipitates at the interface as calcite. The extent of this process seems to be strongly related to the bentonite density. The steel coupon was removed prior to embedding, with the location marked as resin in Fig. 1. A line scan from the edge towards the bulk bentonite did not indicate any systematic gradient in the Fe2+/3+ ratio. The formation of mixed Fe2+/3+ silicate compounds appears to be heterogeneous. This work contributes to an increasing understanding of steel corrosion mechanisms in clay, which can improve the robustness of canister lifetime predictions.
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"NCRP Report No. 141: Managing Potentially Radioactive Scrap Metal". Journal of Radiological Protection 23, n. 3 (9 settembre 2003): 357. http://dx.doi.org/10.1088/0952-4746/23/3/701.
Testo completo
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Tran-Quang, Vinh, e Hung Dao-Viet. "An internet of radiation sensor system (IoRSS) to detect radioactive sources out of regulatory control". Scientific Reports 12, n. 1 (3 maggio 2022). http://dx.doi.org/10.1038/s41598-022-11264-y.
Testo completoAbstract (sommario):
AbstractA radioactive source that is not under regulatory control, either because it has never been under regulatory control or because it has been abandoned, lost, misplaced, stolen, or otherwise transferred without proper authorization, is considered an orphan source. Orphan sources are usually gathered as scrap metal because of their heavy metallic containers. Melting an orphan source with scrap metal produces contaminated recycled metal and waste; the consequences will be extremely serious for humans and the environment, affecting the economy and social stability. In this paper, we propose and develop an Internet of Radiation Sensor System (IoRSS) to detect radioactive sources out of regulatory control in scrap metal recycling and production facilities. It is a complete IoT system consisting of a network of wirelessly connected radiometric devices that optimizes the detection, localization, and identification of radioactive sources by integrating data from multiple portable radiation detectors. The proposed IoRSS system creates a robust and flexible network architecture along with advanced data fusion algorithms that combine information from many detectors. The IoRSS system provides advanced search and monitoring capabilities in a large coverage area and in difficult operational environments.
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Da Costa, Evaldo Luiz Correa, Joana D'Arc Ramos Lopes Gomes, Rogério Dos Santos Gomes, Mara Lucia De Lara Costa e Zieli Dutra Thomé Filho. "The regulatory control over radiation sources: the Brazilian experience and some lessons learned from industrial applications". Brazilian Journal of Radiation Sciences 7, n. 2A (20 febbraio 2019). http://dx.doi.org/10.15392/bjrs.v7i2a.671.
Testo completoAbstract (sommario):
This study gives an overview of the activities of the National Commission of Nuclear Energy (CNEN), as the Brazilian nuclear regulatory authority. These activities are described, especially those related to management of orphan sources and radioactive material in scrap metal considering the actions already put into place by CNEN during the licensing and controlling of radioactive sources in the industry and other facilities. In Brazil, there is not yet an effective system for controlling the scrap metal and recycling industry, thus a coordinated approach to achieve a harmonized and effective response with the involvement of third parties is needed, especially the metal industries and ores facilities. These practices call for stringent regulatory control, in order to reduce the occurrence of orphan sources, and consequently, radioactive material appearing in scrap metal. Some challenges of managing the national radiation sources register systems will be discussed, in order to cover effectively all the radiation source history (in a ‘from the cradle to the grave’ basis), and the dynamic maintenance and update of these data. The main industrial applications considered in this work are those dealing with constant movement of sources all over the country, with geographical issues to be considered in the managing and controlling actions, such as gammagraphy and well-logging. This study aims to identify and promote good practices to prevent inadvertent diversion of radioactive material, taking into account existing international recommendations and some lessons learned in national level.
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"An IoT System for Radioactive Material Detection in Scrap Metal Recycling and Production Facilities". JST: Smart Systems and Devices 32, n. 1 (15 gennaio 2022): 85–93. http://dx.doi.org/10.51316/jst.155.ssad.2022.32.1.11.
Testo completoAbstract (sommario):
A radioactive source that is not under regulatory control because it is abandoned, lost, misplaced, stolen, or transferred without proper authorization is referred to as an orphan source. The melting of an orphan source, when mixed with scrap metal, has resulted in contaminated recycled metal and wastes and the consequences will be very serious for humans and the environment. In this paper, we propose and develop an Internet of Radiation Sensor System (IoRSS) to enhance the use of nuclear detection systems to detect nuclear and other radioactive materials out of regulatory control at points of entry/exit and other trade locations of scrap metal recycling and production facilities. The proposed IoRSS creates a robust and flexible network architecture along with advanced data fusion algorithms that combine information from many detectors. The test results show that the IoRSS system allows for accurate detection of radioactive sources and provides appropriate radiation incident response plans.
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Umemura, A., K. Kimura, K. Takahashi, D. Sakurai, M. Yamamoto e S. Abe. "Radioactive Tracer Test to Develop a Recycling System for Operating Reactor Scrap Metal". MRS Proceedings 353 (1994). http://dx.doi.org/10.1557/proc-353-1333.
Testo completoAbstract (sommario):
AbstractA demonstration test using radio-isotope(RI) tracers during the manufacturing of inner drum shielding material from the recycling of operating reactor scrap metal was completed and the following results were obtained. The behaviour of five radionuclides (Mn-54. Co-60. Zn-65. Sr-85 and Cs-137) was established. The time-dependent behaviors of the radionuclides in molten steel and in slag were investigated. The radioactivity distributions in metal products were homogeneous. Dose equivalent rates in the working area were below background levels and radioactive dust concentrations in the air were below detection limits.
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James, I. U., E. Onuh, I. F. Moses, U. E. Ukeme e J. N. Vandi. "ASSESSMENT OF OUTDOOR RADIATION EXPOSURE LEVELS AND HUMAN HEALTH RISK IN A MAJOR SCRAP METAL MARKET IN ABUJA". International Journal of Advanced Academic Research, 2 giugno 2021, 92–102. http://dx.doi.org/10.46654/ij.24889849.e7573.
Testo completoAbstract (sommario):
Background: Scrap metal can contain sources of radiation with the associated environmental and health risks. Radioactive substances can become associated with scrap metal in various ways and if not discovered they can be incorporated into steel and non-ferrous metals through the melting process. This can cause health hazards to workers and to the public as well as environmental concerns Objectives: this study aimed at assessing the outdoor radiation exposure levels and human health risk in a major scrap metal market in Abuja, FCT. Method: An in-situ measurement approach was adopted using a factory calibrated Radiagem-2000 Universal Survey Meter and a handheld Global Positioning System (Garmin GPS 76S) equipment. The monitor was suspended in air at one meter above the ground level. Readings were obtained between the hours of 1200 and 1600 hours since the exposure rate meter has a maximum response to environmental radiation within these hours. Results: The results showed that the average values for the outdoor exposure dose rate for the three location ranges from 0.173±0.042 μSv/h to 0.177±0.046 μSv/h with a mean of 0.176±0.045 μSv/h. These values, though, slightly higher than the standard background radiation of 0.133 μSv/h,are below the ICRP maximum permissible limit of 0.57 μSv/h. The results also show that the AEDE values are lower than the ICRP recommended limits of 1.0 mSv/y for the public and 20 mSv/y for occupationally exposed workers. The ELCR ranges from 0.5926 x 10-3 to 0.6049 x 10-3 with a mean of 0.6008 x 10-3 which is 2.1 times higher than the world’s average. The dosage to organs received shows that the testes have the highest dose while the liver has the lowest dose. The result of the dose to the organs showed that all the values are below the international tolerable limits. Conclusion: Generally, The radiological assessment shows that the study area does not constitute any immediate radiological health effect on the workers and the general public due to radiation exposure rate.
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Tomek, Miroslav, Eleonóra Benčíková, Jan Strohmandl e Pavel Tomášek. "IDENTIFICATION AND ASSESSMENT OF OCCUPATIONAL SAFETY RISKS IN CASE OF FAILURE TO CAPTURE AN ORPHAN SOURCE OF IONIZING RADIATION". Journal of Applied Engineering Science, 4 ottobre 2022, 1–10. http://dx.doi.org/10.5937/jaes0-36057.
Testo completoAbstract (sommario):
Occupational safety and health belong to fundamental human rights. This fully applies to the protection of employees and other persons, which operate or are located in facilities for the collection of scrap metal. The founder of the landfill or the employer has an irreplaceable place in the field of protection of persons against the effects of ionizing radiation. Based on the identification and assessment of occupational safety risks in the event of failure to ensure timely detection of an orphan source of ionizing radiation, the operator must assess all risk factors with emphasis on radiation. At the same time, it must take specific regime measures, which would minimize the impact on people and the environment. The article deals with the causes of failure the system of protection against the effects of ionizing radiation. The assessment of these causes is performed using the fault tree analysis method with the application of Boolean equations. The result of solving the problem is the calculation of the failure of the regime protection system in the devices, intended for the collection of scrap metal, caused by human error as a result of intentional or negligent actions of the operator and insufficient training in the areas of control of measuring devices, principles of correct use of detection devices, insufficient visual identification of potentially dangerous objects. The contribution of this paper is in the design of appropriate regime measures eliminating the consequences of non–capturing a source of ionizing radiation.
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Zorloni, Gabriele, Paolo Tancioni e Marco Caresana. "Feasibility study of a shielding-independent radiation portal monitor system for revealing 241-Am orphan sources in radiometric surveillance of scrap metal". European Physical Journal Plus 135, n. 9 (settembre 2020). http://dx.doi.org/10.1140/epjp/s13360-020-00742-9.
Testo completoAbstract (sommario):
Abstract Orphan radioactive sources inadvertently melted in steel plants are a health and economical hazard. Thus, regulation authorities impose strict control measurements to be performed at these plants. However, a recent series of incidents related to the melting of $${}^{241}\hbox {Am}$$ 241 Am sources demonstrated the inadequacy of even state of the art systems in revealing this low-energy gamma ray emitter up to activities of the order of hundreds GBq. However, $${}^{241}\hbox {Am}$$ 241 Am sources are characterized by a weak neutron emission which can be detected by proper monitor systems. This work provides a feasibility study of a shielding-independent neutron-sensitive portal monitor system to be installed in steel plants. Measurements were performed both with a certified $${}^{241}\hbox {Am}$$ 241 Am shielded source and at the weighing area of a steel plant, to assess both the detector performance and the practical feasibility of the system implementation in work-place fields. A risk evaluation analysis demonstrated that with the current control systems $${}^{241}\hbox {Am}$$ 241 Am sources up to 185 GBq could pass undetected with a potential exposure for workers equal to 1.7 mSv, consistent with recent accidents reports. The proposed technique could reveal $${}^{241}\hbox {Am}$$ 241 Am activities down to 2 GBq, decreasing the worker exposure down to 24 $$\upmu \hbox {Sv}$$ μ Sv , without interfering with the standard plant operations.
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Seetharaman, Seshadri, e Olle Grinder. "New extraction process for recovery of metals in glass deposits". Linnaeus Eco-Tech, 31 gennaio 2017. http://dx.doi.org/10.15626/eco-tech.2014.020.
Testo completoAbstract (sommario):
A new process, named salt extraction process, has been developed to enable recovery of metal values from secondary sources e.g. scrap and waste materials such as slag and flue dust. It is also feasible in extracting metals from certain ores that normally are difficult to enrich and process by traditional metallurgy – two examples are nickel and cobalt. The salt extraction process has also been applied in the recovery of metals from silicates including lead from glass wastes.The process is based on the extraction of metal values from the raw materials into a molten salt bath consisting of NaCl, LiCl, and KCl corresponding to the ternary eutectic composition and with AlCl3 dissolved in the salt melt acting as the chlorinating agent. This is followed by the electrolysis of the salt bath in the same reactor. The normal processing temperature is in the range 973 K (700 °C) to 1173 K (900 °C). The aluminium chloride in the salt bath reacts with the metals in the fine comminuted raw material and metal ions are formed in the chloride bath. During the electrolysis, the metal ions reach the solid cathode and get deposited in metallic form. Liquid aluminium is used as the anode. Chlorine gas formed at the anode reacts with aluminium forming aluminium chloride in situ, which gets dissolved in the salt melt supplying the required amount of the flux.The salt extraction process has been used successfully in the extraction of Cr and Fe from electric arc furnace (EAF) silicate slag. Experiments have also been carried out in which lead has been recovered with high yield from spent cathode ray tubes. The process was shown to be successful in the extraction of the rare-earth metals neodymium and dysprosium from permanent magnet scrap. The method is a highly promising process route for the recovery of strategic metals. It also has the added important advantage of being environment-friendly, with only small amount recyclable, potentially useful rest products like alumina and silica as with limited energy consumption.
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Vázquez-Campos, Xabier, Andrew S. Kinsela, Mark W. Bligh, Timothy E. Payne, Marc R. Wilkins e T. David Waite. "Genomic Insights Into the Archaea Inhabiting an Australian Radioactive Legacy Site". Frontiers in Microbiology 12 (18 ottobre 2021). http://dx.doi.org/10.3389/fmicb.2021.732575.
Testo completoAbstract (sommario):
During the 1960s, small quantities of radioactive materials were co-disposed with chemical waste at the Little Forest Legacy Site (LFLS, Sydney, Australia). The microbial function and population dynamics in a waste trench during a rainfall event have been previously investigated revealing a broad abundance of candidate and potentially undescribed taxa in this iron-rich, radionuclide-contaminated environment. Applying genome-based metagenomic methods, we recovered 37 refined archaeal MAGs, mainly from undescribed DPANN Archaea lineages without standing in nomenclature and ‘Candidatus Methanoperedenaceae’ (ANME-2D). Within the undescribed DPANN, the newly proposed orders ‘Ca. Gugararchaeales’, ‘Ca. Burarchaeales’ and ‘Ca. Anstonellales’, constitute distinct lineages with a more comprehensive central metabolism and anabolic capabilities within the ‘Ca. Micrarchaeota’ phylum compared to most other DPANN. The analysis of new and extant ‘Ca. Methanoperedens spp.’ MAGs suggests metal ions as the ancestral electron acceptors during the anaerobic oxidation of methane while the respiration of nitrate/nitrite via molybdopterin oxidoreductases would have been a secondary acquisition. The presence of genes for the biosynthesis of polyhydroxyalkanoates in most ‘Ca. Methanoperedens’ also appears to be a widespread characteristic of the genus for carbon accumulation. This work expands our knowledge about the roles of the Archaea at the LFLS, especially, DPANN Archaea and ‘Ca. Methanoperedens’, while exploring their diversity, uniqueness, potential role in elemental cycling, and evolutionary history.
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Mallants, D., L. Wang, E. Weetjens e W. Cool. "Evaluating Chemical Toxicity of Surface Disposal of LILW-SL in Belgium". MRS Proceedings 1107 (2008). http://dx.doi.org/10.1557/proc-1107-689.
Testo completoAbstract (sommario):
AbstractONDRAF/NIRAS is developing and evaluating a surface disposal concept for low and intermediate level short-lived radioactive waste (LILW-SL) at Dessel, Belgium. In support of ONDRAF/NIRAS's assignment, SCK•CEN carried out long-term performance assessment calculations for the inorganic non-radioactive components that are present in LILW-SL. This paper summarizes the results obtained from calculations that were done for a heavily engineered surface disposal facility at the nuclear zone of Mol/Dessel. The calculations address the migration of chemotoxic elements from the disposed waste to groundwater.Screening calculations were performed first to decide which non-radioactive components could potentially increase concentrations in groundwater to levels above the groundwater standards. On the basis of very conservative calculations, only 6 out of 41 chemical elements could not be classified as having a negligible impact on man and environment. For each of these six elements (B, Be, Cd, Pb, Sb, and Zn), the source term was characterized in terms of its chemical form (i.e., metal, oxide, or salt), and a macroscopic transport model built that would capture the small-scale dissolution processes relevant to element release from a cementitious waste container. Furthermore, reliable transport parameters in support of the convection-dispersion-retardation (CDR) transport calculations were determined. This included derivation of (1) solubility for a cementitious near field environment based on thermodynamic equilibrium calculations with The Geochemist's Workbench, and (2) distribution coefficients based on a compilation of literature values. Scoping calculations illustrated the effects of transport parameter uncertainty on the rates at which inorganic components in LILW-SL leach to groundwater.
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Wittwer, Yves, Robert Eichler, Ronald Zingg, Dominik Herrmann e Andreas Türler. "The influence of gas purification and addition of macro amounts of metal-carbonyl complexes on the formation of single-atom metal-carbonyl-complexes". Radiochimica Acta, 1 settembre 2021. http://dx.doi.org/10.1515/ract-2020-0036.
Testo completoAbstract (sommario):
Abstract Using the Fast On-line Reaction Apparatus (FORA), the influence of various gas-purification columns onto the formation of metal carbonyl complexes (MCCs) under single-atom chemistry conditions was investigated. MCCs were synthesized from single atoms of Mo, Tc, Ru and Rh being produced by the spontaneous fission of 252Cf and recoiling into a CO-gas containing carrier gas atmosphere. The in-situ synthesized MCCs were volatile enough to be transported by the carrier gas to a charcoal trap where they were adsorbed and their subsequent decay was registered by γ-spectrometry. It was found that the type and combination of purification columns used to clean the applied CO-gas strongly influences the obtained formation and transport yields for all MCCs. With the exception of Rh-carbonyl, intense gas-purification strategies resulted in reduced formation and transport yields for MCCs in comparison with less efficient or even completely missing purification setups. It was postulated that the observed reduction in yield might depend on the content of Fe(CO)5 and Ni(CO)4, as well as potentially other MCCs, in the CO-gas, being formed by the interaction between CO and the steel-surfaces of FORA as well as from impurities in the used charcoal traps. Subsequently, it was shown that macro amounts of Fe(CO)5, Ni(CO)4, Mo(CO)6 and Re2(CO)10 added to the used process gas indeed increase significantly the overall yields for MCCs produced by 252Cf fission products. Ni(CO)4 appeared the most potent to increase the yield. Therefore, it was used in more detailed investigations. Using isothermal chromatography, it was shown that Ni(CO)4 does not affect the speciation of carbonyl species produced by the 252Cf fission product 104Mo. For 107Tc, 110Ru and 111Rh a speciation change cannot be excluded. For 111Rh a speciation change cannot be excluded. An inter-carbonyl transfer mechanism is suggested boosting the formation of MCCs. The current discovery might allow for new opportunities in various research fields, which are currently restricted by the low overall yields for MCCs produced under single-atom chemistry conditions. Examples are the chemical investigation of transactinides or the generation of radioactive ion beams from refractory metals at accelerators.
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Bhaduri, Debarati, Debjani Sihi, Arnab Bhowmik, Bibhash C. Verma, Sushmita Munda e Biswanath Dari. "A review on effective soil health bio-indicators for ecosystem restoration and sustainability". Frontiers in Microbiology 13 (17 agosto 2022). http://dx.doi.org/10.3389/fmicb.2022.938481.
Testo completoAbstract (sommario):
Preventing degradation, facilitating restoration, and maintaining soil health is fundamental for achieving ecosystem stability and resilience. A healthy soil ecosystem is supported by favorable components in the soil that promote biological productivity and provide ecosystem services. Bio-indicators of soil health are measurable properties that define the biotic components in soil and could potentially be used as a metric in determining soil functionality over a wide range of ecological conditions. However, it has been a challenge to determine effective bio-indicators of soil health due to its temporal and spatial resolutions at ecosystem levels. The objective of this review is to compile a set of effective bio-indicators for developing a better understanding of ecosystem restoration capabilities. It addresses a set of potential bio-indicators including microbial biomass, respiration, enzymatic activity, molecular gene markers, microbial metabolic substances, and microbial community analysis that have been responsive to a wide range of ecosystem functions in agricultural soils, mine deposited soil, heavy metal contaminated soil, desert soil, radioactive polluted soil, pesticide polluted soil, and wetland soils. The importance of ecosystem restoration in the United Nations Sustainable Development Goals was also discussed. This review identifies key management strategies that can help in ecosystem restoration and maintain ecosystem stability.