126 research outputs found

    Risk Governance of Emerging Technologies Demonstrated in Terms of its Applicability to Nanomaterials

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    Nanotechnologies have reached maturity and market penetration that require nano-specific changes in legislation and harmonization among legislation domains, such as the amendments to REACH for nanomaterials (NMs) which came into force in 2020. Thus, an assessment of the components and regulatory boundaries of NMs risk governance is timely, alongside related methods and tools, as part of the global efforts to optimise nanosafety and integrate it into product design processes, via Safe(r)-by-Design (SbD) concepts. This paper provides an overview of the state-of-the-art regarding risk governance of NMs and lays out the theoretical basis for the development and implementation of an effective, trustworthy and transparent risk governance framework for NMs. The proposed framework enables continuous integration of the evolving state of the science, leverages best practice from contiguous disciplines and facilitates responsive re-thinking of nanosafety governance to meet future needs. To achieve and operationalise such framework, a science-based Risk Governance Council (RGC) for NMs is being developed. The framework will provide a toolkit for independent NMs' risk governance and integrates needs and views of stakeholders. An extension of this framework to relevant advanced materials and emerging technologies is also envisaged, in view of future foundations of risk research in Europe and globally

    An Overview on Nanotechnology Activities in Iran

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    "nDuring the last decade, nanotechnology has gained remarkable attention by international scientific and industrial societies. In this respect, various countries have launched their short and long-term programs to benefit from the huge market ex­pected by utilization and implementation of this technology in their industrial/technological infrastructures. Islamic republic of Iran, also by considering the undeniable impact of this technology on her nation's wealth and economy, initiated her na­tional nanotechnology development plan referred to as "Future Strategy" in 2005. The strategic plan outlines countries ma­jor action plans for ten-year period up to 2015 with the target to be amongst the top 15 countries active in this very impor­tant area. This paper, while reviewing briefly the objects, targets of the plan will also consider the status and achievements ob­tained by implementation of this strategic plan. Further, the impact of various developed infrastructures on the success of the program will be also discussed.   &nbsp

    Effect of calcination atmosphere on the structure and photocatalytic properties of titania mesoporous powder

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    In the work presented here, mesoporous titania (MTO) powders are synthesised by the sol-gel method using amphiphilic triblock copolymer as a template in two different calcination atmospheres, N and air. Various techniques such as sequential thermal analysis (STA), small-angle X-ray diffraction (SAXRD), wide-angle X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet (UV)-visible spectroscopy, high-resolution transmission electron microscopy (HRTEM) and N -adsorption/desorption analysis were utilised to study the prepared samples. Furthermore, the photocatalytic activities of the prepared samples were evaluated from the photo-degradation analysis of methylene blue (MB). For the sample calcined at N , the formation of an ordered mesostructure with a high specific surface area (172 m g ), mesoporosity (48%) and enhanced photocatalytic activity were obtained compared to that of the sample calcined in air. The observed increased MB degradation for the latter is mainly attributed to the formation of higher specific surface area and mesoporosity. The availability of highly ordered open-pore channels could provide increased contacts between reactants in the solution and the active sites on the surface of titania mesoporous particles. Considering the photoactivities of the samples, it is revealed that the photocatalytic activity is enhanced, together with an increase in the surface defects in N atmosphere

    PREPARATION OF Fe/GLASS COMPOSITE BY REDUCTION OF Na2O– Fe2O3–B2O3–SiO2–ZnO GLASS AND GLASS CERAMICS

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    In the present study, the feasibility of α-Fe ferromagnetic phase formation in glass and glass-ceramic by reduction in hydrogen atmosphere have been investigated. The glass with the composition of 35Na 2 O–24Fe2O3–20B 2O3 – 20SiO 2 –1ZnO (mol %) was melted and quenched by using a twin roller technique. As quenched glass flakes were heat treated in the range of 400-675 °C for 1-2 h in hydrogen atmosphere, which resulted in reduction of iron cations to α-Fe and FeO. The reduction of iron cations in glass was not completely occurred. Saturation magnetization of these samples was 8-37 emu g -1 . For the formation of glass ceramic, As quenched glass flakes heat treated at 590 °C for 1 h. Heat treatment of glass ceramic containing magnetite at 675°C in hydrogen atmosphere for 1 h led to reduction of almost all of the iron cations to α-Fe. Saturation magnetization of this sample increased from 19.8 emu g -1 for glass ceramic to 67 emu g -

    A Clinical Decision Support System for Predicting the Early Complications of One-Anastomosis Gastric Bypass Surgery

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    Background/Objective: One of the most effective treatments for patients with obesity, albeit with some complications, is obesity surgery. The aim of this study was to develop a clinical decision support system (CDSS) to predict the early complications of one-anastomosis gastric bypass (OAGB) surgery. Subjects/Methods: This study was conducted in Tehran, Iran on patients who underwent OAGB surgery in 2011�2014 in five hospitals. Initially, variables affecting the OAGB early complications were identified using the literature review. Patients� data were extracted from an existing database of obesity surgery. Then, different artificial neural networks (ANNs) (multilayer perceptron (MLP) network) were developed and evaluated for prediction of 10-day, 1-month, and 3-month complications. Results: Factors including age, BMI, smoking status, intra-operative complications, comorbidities, laboratory tests, sonography results, and endoscopy results were considered important factors for predicting early complications of OAGB. A CDSS was developed with these variables. The accuracy, specificity, and sensitivity of the 10-day prediction system in the test data were 98.4, 98.6, and 98.3, respectively. These figures for 1-month system were 96, 93, and 98.4 and for the 3-month system were 89.3, 86.6, and 91.5, respectively. Conclusions: Using the CDSS designed, we could accurately predict the early complications of OAGB surgery. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

    Synthesizing CoFe2O4 by Glass-Ceramic Method and Characterizing its Magnetic Properties in Na2O-Fe2O3-CoO-B2O3-SiO2 System

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    In this investigation, the effect of heat treatment on magnetic properties of glass and nano-structured cobalt-ferrite glass-ceramic was studied. The glass was synthesized in the system of Na2O-Fe2O3-CoO-B2O3-SiO2. Based on DTA results, heat treatment was done at different times and temperatures. X-ray diffraction pattern of glass-ceramic showed the crystallization of CoFe2O4 and some nonmagnetic phases. The highest magnetization of 11.8 emu/g was obtained for the sample heat-treated for 2 hr at 670C in graphite bed. Average crystallite size of CoFe2O4 in this sample was 50 nm. Scanning Electron Microscopy (SEM) confirmed the formation of cobalt ferrite nanoparticles in the glass matrix

    INFLUENCE OF THE PREPARATION METHOD ON THE STRUCTURE,PHASE FORMATION AND MAGNETIC PROPERTIES OF TEMPLATED CUFE2O4 SPINEL

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    The synthesis of mesoporous CuFe2O4 spinel by several nanocasting strategies (i.e., multi-step nanocasting, one step nanocasting, modified solid-liquid), in which copper and iron nitrates are used as precursors and Pluronic P123 as surfactant, is explored. We have also checked the effect of pH, citric acid and sodium citrate in multi-step nanocasting method. The modified solid-liquid method which contains impregnating mesoporous silica by molten state salts in a non-ionic solvent seems to be the best choice to obtain single phase ordered mesoporous copper ferrite. Other methods suffer from the presence of copper oxide or hematite as impurities or lack of integrity in the mesoporous structure. Increasing pH up to 9.5 does not enhance the phase formation inside the pores of the silica matrix. The citric acid yields a fine structure but does not facilitate the phase formation. Adding sodium citrate neither heals the phase formation nor the structure of the final product. Moreover, vinyl- functionalized mesoporous silica exploited in this study as a hard template entraps both metal nitrates in the pores, assisting impregnation procedur
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