1,720,952 research outputs found
Fast Identification of Bound Structures in Large N-body Simulations
No full textWe present an algorithm that is designed to allow the efficient identification and preliminary dynamical analysis of thousands of structures and substructures in large N-body simulations. First, we utilize a refined density gradient system (based on denmax) to identify the structures and then apply an iterative approximate method to identify unbound particles, allowing fast calculation of bound substructures. After producing a catalogue of separate energetically bound substructures, we check to see which of these are energetically bound to adjacent substructures. For such bound complex subhaloes, we combine components and check if additional free particles are also bound to the union, repeating the process iteratively until no further changes are found. Thus, our subhaloes can contain more than one density maximum, but the scheme is stable: starting with a small smoothing length initially produces small structures that must be combined later and starting with a large smoothing length produces large structures within which sub-substructure is found. We apply this algorithm to three simulations. Two that are using the TPM algorithm by Bode, Ostriker & Xu and one on a simulated halo by Diemand, Moore & Stadel. For all these haloes, we find about 5–8 per cent of the mass in substructures
Stability of polymersomes containing 111in using pertubed angular correlation spectroscopy
No full textThe PAC spectrometer has been successfully applied in the field of chemistry and biology for decades. The current study has shown the method’s potential to investigate the stability of PBD-b-PEO polymersomes by looking at the kinetics of free 111In3+ and 111In bound to Tropolone and DTPA molecules. Unfortunately no conclusive results were yet obtained. Ideally the polymersome membrane has no influence on the molecular tumbling of the 111In entrapped inside. It was expected similar perturbation factors to be obtained for 111In-DTPA in solution and the loaded polymersomes. This was not the case. Assuming the PAC system functions correctly, one possible explanation is the leakage of the polymersomes. Another explanation, sustained as well by the scattered results, is that the correlation times of the 111In-DTPA respectively 111In-Tropolone, are too small to be detected by the PAC. Because PAC has not been previously used to investigate 111In loaded polymersomes, the results could not be confirmed nor infirmed. Nevertheless a future research could provide valuable information.Medical PhysicsBiomedical EngineeringMechanical, Maritime and Materials Engineerin
The Terra Incognita of sampling: Grouping and segregation
No full textRadiation Radionuclides and ReactorsApplied Science
Vocabulary of radioanalytical methods (IUPAC Recommendations 2020)
No full textThese recommendations are a vocabulary of basic radioanalytical terms which are relevant to radioanalysis, nuclear analysis and related techniques. Radioanalytical methods consider all nuclear-related techniques for the characterization of materials where 'characterization' refers to compositional (in terms of the identity and quantity of specified elements, nuclides, and their chemical species) and structural (in terms of location, dislocation, etc. of specified elements, nuclides, and their species) analyses, involving nuclear processes (nuclear reactions, nuclear radiations, etc.), nuclear techniques (reactors, accelerators, radiation detectors, etc.), and nuclear effects (hyperfine interactions, etc.). In the present compilation, basic radioanalytical terms are included which are relevant to radioanalysis, nuclear analysis and related techniques. Accepted Author ManuscriptRST/Applied Radiation & Isotope
Instrumental and organizational aspects of a neutron activation analysis laboratory
No full textApplied Science
Opportunities for innovation in neutron activation analysis
Get PDFNeutron activation laboratories worldwide are at a turning point at which new staff has to be found for the retiring pioneers from the 1960s–1970s. A scientific career in a well-understood technique, often characterized as ‘mature’ may only be attractive to young scientists if still challenges for further improvement and inspiring new applications can be offered. The strengths and weaknesses of neutron activation analysis (NAA) are revisited to identify opportunities for innovation. Position-sensitive detection of elements in large samples, Monte Carlo calculations replacing the use of standards, use of scintillator detectors and new deconvolution techniques for increasing the sensitivity are examples of challenging new roads in NAA. Material science provides challenges for the application of NAA in both bulk samples, ultrathin layers and ultrapure materials.Radiation, Radionuclides and ReactorsApplied Science
De thermische ontleding van magnesiumchloride naar magnesiumoxide met zoutzuurbereiding
No full textDocument(en) uit de collectie Chemische Procestechnologie.DelftChemTechApplied Science
A process for the production of no-carrier added 99Mo
No full textAbstract of WO 2009148306 (A1) The present invention relates to a process for the production of no-carrier added 99Mo by neutron activation of 98Mo thereby reaching specific radioactivity which allow the use of such produced 99Mo as an option for the 99Mo produced by the fission of 235U. This has been achieved by taking advantage of the recoil of the 99Mo nuclei upon the capture of neutrons by the 98Mo containing compound. These recoiled nuclei are no longer chemically bound to the 98Mo containing compound allowing further specific separation. Preferred 98Mo containing compounds are molybdenum(0)hexacarbonyl [ (Mo (CO) 6] and molybdenum (VI ) di oxodioxinate [C4H3 (O) -NC5H3) J2-MoO2.Radiation, Radionuclides and ReactorsApplied Science
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