Emergency unmanned airborne spectrometric (HPGe) monitoring system.

After a nuclear or radiation event, emergency responders and radiation protection authorities need quick and credible information based on reliable accident and post-accident radiological data. However, risks to people in the vicinity of the source pose serious measurement challenges. Many problems could be solved by unmanned airborne monitoring systems, but the current ones are mostly based on non-spectrometric detectors carried by drones with low bearing, short flying range and flight time.

Electric Potential Profiles in a Model Single-Path Electrodialysis Unit.

Electrodialysis is an important electromembrane separation process anticipated to play a significant role in developing future technologies. It produces ion-depleted and ion-concentrated product streams, intrinsically suggesting the formation of spatial gradients of relevant quantities. These quantities affect local conditions in an electrodialysis unit.

Selection of Covalent Organic Framework Pore Functionalities for Differential Adsorption of Microcystin Toxin Analogues.

Microcystins (MCs), produced by sp, are the most commonly detected cyanotoxins in freshwater, and due to their toxicity, worldwide distribution, and persistence in water, an improvement in the monitoring programs for their early detection and removal from water is necessary. To this end, we investigate the performance of three covalent organic frameworks (COFs), TpBD-(CF), TpBD-(NO), and TpBD-(NH), for the adsorption of the most common and/or toxic MC derivatives, MC-LR, MC-RR, MC-LA, and MC-YR, from water. While MC-LR and MC-YR can be efficiently adsorbed using all three COF derivatives, high adsorption efficiencies were found for the most lipophilic toxin, MC-LA, with TpBD-(NH), and the most hydrophilic one, MC-RR, with TpBD-(NO).

Extraction of Ibuprofen from Natural Waters Using a Covalent Organic Framework.

Ibuprofen is one of the most widely used pharmaceuticals, and due to its inefficient removal by conventional wastewater treatment, it can be found in natural surface waters at high concentrations. Recently, we demonstrated that the TpBD-(CF) covalent organic framework (COF) can adsorb ibuprofen from ultrapure water with high efficiency. Here, we investigate the performance of the COF for the extraction of ibuprofen from natural water samples from a lake, river, and estuary.

Robust Aluminum and Iron Phosphinate Metal-Organic Frameworks for Efficient Removal of Bisphenol A.

Porous metal-organic frameworks (MOFs) have excellent characteristics for the adsorptive removal of environmental pollutants. Herein, we introduce a new series of highly stable MOFs constructed using Fe and Al metal ions and bisphosphinate linkers. The isoreticular design leads to ICR-2, ICR-6, and ICR-7 MOFs with a honeycomb arrangement of linear pores, surface areas up to 1360 m g, and high solvothermal stabilities.

How N-(pyridin-4-yl)pyridin-4-amine and its methyl and nitro derivatives are arranged in the interlayer space of zirconium sulfophenylphosphonate: a problem solved by experimental and calculation methods.

Classical molecular simulation methods were used for a description of an arrangement of intercalated molecules N-(pyridin-4-yl)pyridin-4-amine (AH) and its derivatives, 3-methyl-N-(pyridin-4-yl)pyridin-4-amine (AMe), and 3-nitro-N-(pyridin-4-yl)pyridin-4-amine (ANO2) within a layered structure of zirconium 4-sulfophenylphosphonate. The intercalated molecules were placed between SOH groups of the host layers. Their mutual positions and orientations were solved by molecular simulation methods and compared with the presented experimental results.

Effect of channel geometry on ion-concentration polarization-based preconcentration and desalination.

Polarization of the ion-selective systems results in the formation of ion-depleted and ion-concentrated zones in the electrolyte layers adjacent to the system. One can employ ion-concentration polarization for the removal of charged large molecules and small ions from the flowing liquid. Removal of large molecules from the flowing solution and their local accumulation is often referred to as preconcentration, removal of small ions as desalination.

Adsorption of nerve agent simulants onto vermiculite structure: Experiments and modelling.

Chemical warfare agents are still a threat to humanity despite the existence of a ban on their production and use. There are many new materials that have been experimentally verified to be effective in degrading and eliminating various chemical warfare agents; however, clay minerals still remain very effective, environmentally friendly and not expensive. Vermiculites modified with hexadecylpyridinium, hexadecyltrimethylammonium and tetramethylammonium cations were used for static sorption of vapours of two simulants of nerve agents: dimethyl methyl phosphonate and diethyl ethyl phosphonate.

The Role of von Willebrand Factor, ADAMTS13, and Cerebral Artery Thrombus Composition in Patient Outcome Following Mechanical Thrombectomy for Acute Ischemic Stroke.

BACKGROUND The aim of the study was to investigate the role of von Willebrand factor (vWF), the vWF-cleaving protease, ADAMTS13, the composition of thrombus, and patient outcome following mechanical cerebral artery thrombectomy in patients with acute ischemic stroke. MATERIAL AND METHODS A prospective cohort study included 131 patients with ischemic stroke (<6 hours) with or without intravenous thrombolysis. Interventional procedure parameters, hemocoagulation markers, vWF, ADAMTS13, and histological examination of the extracted thrombi were performed.

Alkaline-earth metal phenylphosphonates and their intercalation chemistry.

The intercalation chemistry of layered alkaline-earth metal phenylphosphonates with the general formula MeCHPO·2HO (Ca, Sr, Ba) is reviewed. The preparation of the host materials is described and their behavior in dependence on the relative humidity and pH of the reaction medium is discussed. Mutual relationships between MeCHPO·2HO and Me(CHPOH) were investigated using a method of computer-controlled addition of reagents.

Geometry optimization of zirconium sulfophenylphosphonate layers by molecular simulation methods.

Classical molecular simulation methods were used for a detailed structural description of zirconium 4-sulfophenylphosphonate and zirconium phenylphosphonate 4-sulfophenylphosphonates with general formula Zr(HOSCHPO) (CHPO) ·yHO (x = 0.7-2; y = 0 or 2). First, models describing the structure of zirconium 4-sulfophenylphosphonate (x = 2) were calculated for the hydrated (y = 2) and dehydrated (y = 0) compounds.

Metrology for decommissioning nuclear facilities: Partial outcomes of joint research project within the European Metrology Research Program.

Decommissioning of nuclear facilities incurs high costs regarding the accurate characterisation and correct disposal of the decommissioned materials. Therefore, there is a need for the implementation of new and traceable measurement technologies to select the appropriate release or disposal route of radioactive wastes. This paper addresses some of the innovative outcomes of the project "Metrology for Decommissioning Nuclear Facilities" related to mapping of contamination inside nuclear facilities, waste clearance measurement, Raman distributed temperature sensing for long term repository integrity monitoring and validation of radiochemical procedures.

Subtraction of natural radiation contribution from gamma-ray spectra measured by HPGe detector.

A method is described for the subtraction of Monte Carlo simulated detector spectra of the contribution of natural radiation to measured detector spectra aiming to decrease the decision threshold for the detection of artificial radionuclides. HPGe detector spectra were simulated for selected naturally occurring radionuclides deposited onto a filter used for aerosol collection in a newly developed airborne radioactivity monitoring system. Stepwise, the simulated spectra were fitted to the actually acquired gamma-ray spectrum and the decision threshold was determined.

Advancements in NORM metrology - Results and impact of the European joint research project MetroNORM.

The results of the three years European Metrology Research Programme's (EMRP) joint research project 'Metrology for processing materials with high natural radioactivity' (MetroNORM) are presented. In this project, metrologically sound novel instruments and procedures for laboratory and in-situ NORM activity measurements have been developed. Additionally, standard reference materials and sources for traceable calibration and improved decay data of natural radionuclides have been established.

Monte Carlo optimization of shielding for novel industrial free release measurement facility.

Monte Carlo (MC) simulations were done for the optimization of shielding configuration of a novel industrial radionuclide-specific pre-selection free release measurement facility. The shielding is made from unique bricks of concrete with very low specific activity of natural radionuclides. The final configuration was selected as a compromise between shielding volume and the simulated 1461keV full-energy peak detector count rates of natural K.

Influence of 1,2-alkanediols on the structure of their intercalates with strontium phenylphosphonate solved by molecular simulation and experimental methods.

Strontium phenylphosphonate intercalates with 1,2-diols (from 1,2-ethanediol to 1,2-hexanediol) were synthesized and characterized by X-ray diffraction, thermogravimetry, chemical analysis, and molecular simulation methods. Prepared samples exhibit a very good stability at ambient conditions. Structural arrangement calculated by simulation methods suggested formation of cavities surrounded by six benzene rings.

Distribution of radionuclides in an iron calibration standard for a free release measurement facility.

A Europallet-sized calibration standard composed of 12 grey cast iron tubes contaminated with (60)Co and (110m)Ag with a mass of 246kg was developed. As the tubes were produced through centrifugal casting it was of particular concern to study the distribution of radionuclides in the radial direction of the tubes. This was done by removing 72 small samples (swarf) of ~0.

Intercalation of 1,n-diols into strontium phenylphosphonate: how the shape of the host layers influences arrangement of the guest molecules.

Strontium phenylphosphonate intercalates with 1,n diols (n=2-4, 6-8) having general formula SrC6H5PO3⋅x(HO(CH2)nOH)⋅yH2O were prepared by precipitation from strontium phenylphosphonate solution and the corresponding diols. Prepared compounds exhibit a very good stability at ambient conditions. The intercalates were characterized by X-ray diffraction, thermogravimetry and elemental analysis.

Comparison of properties of digital spectrometer systems.

We have tested two digital spectrometer systems, the DSP 9660 and Lynx(®) modules, connected to a HPGe detector. Lynx(®) is a fully integrated 32K channel signal analyzer based on digital signal processing techniques, which offers advanced digital stabilization. The model DSP 9660 digitalizes the signal directly at a very high sampling rate.

Optimization of a measurement facility for radioactive waste free release by Monte Carlo simulation.

A novel free release measurement facility (FRMF) was developed within the joint research project "Metrology for Radioactive Waste Management" of the European Metrology Research Programme. Before and during FRMF design and construction, Monte Carlo calculations with MCNPX and PENELOPE codes were used to optimize the thickness of the shielding, the dimensions of the container, and the shape of detector collimators. Validation of the numerical models of the FRMF detectors and the results of the optimization are discussed in the paper.

Stabilization of ZnS Nanoparticles in Micellar Dispersion of Cetyltrimethylammonium Bromide.

ZnS nanoparticles were precipitated in micellar dispersions of cetyltrimethylammonium bromide (CTAB). ZnS nanoparticles and cetyltrimethylammonium (CTA+) ions formed positively charged ZnS-CTA micelles with the mode zeta potential of 35 mV. The ZnS-CTA micelles were simulated by molecular modelling that confirmed the formation of positive CTA+ bilayers on the ZnS surface.

Precipitation, stabilization and molecular modeling of ZnS nanoparticles in the presence of cetyltrimethylammonium bromide.

ZnS nanoparticles were precipitated in aqueous dispersions of cationic surfactant cetyltrimethylammonium bromide (CTAB). The sphere radii of ZnS nanoparticles calculated by using band-gap energies steeply decreased from 4.5 nm to 2.

Calibration of stack monitors for measurement of noble gases in nuclear facilities.

In nuclear facilities stack monitors are used for the measurement of the volumetric activity of noble gases. Spectrometric measurement is needed because the content of stack effluents is always a mixture of radionuclides. In some nuclear power plants new types of monitors were installed based on HPGe detectors.

Study of the betulin molecule in a water environment; ab initio and molecular simulation calculations.

Ab initio and molecular simulation methods were used in calculations of the neutral individual betulin molecule, and molecular simulations were used to optimize the betulin molecule immersed in various amounts of water. Individual betulin was optimized in different force fields to find the one exhibiting best agreement with ab initio calculations obtained in the Gaussian03 program. Dihedral torsions of active groups of betulin were determined for both procedures, and related calculated structures were compared successfully.