An improved and scalable synthesis of the unsubstituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene framework facilitates access to the previously unreported parent dipyrrin HCl salt, as well as 4,4-dichloro-4-bora-3a,4a-diaza-s-indacene.

BACKGROUND High-molecular-weight phthalates, such as diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP), are used primarily as polyvinyl chloride plasticizers. OBJECTIVES We assessed exposure to DINP and DIDP in a representative sample of persons ≥ 6 years of age in the U.S. general population from the 2005-2006 National Health and Nutrition Examination Survey (NHANES). METHODS We ...

This paper demonstrates the applicability of Monte Carlo analysis to perform nuclear reactor core simulations with thermofluid feedback from a computational fluid dynamics code. An interface program, McSTAR, was written to couple MCNP5 to the commercial computational fluid dynamics code STAR-CD. McStar is a Perl script which alternately executes MCNP5, STAR-CD and cross section update routines ...

Following the design of the German research reactor, FRM-II, which delivers high thermal neutron fluxes, we have already developed an asymmetric compact cylindrical core with an inner and outer reflector. The goal was to maximize the maximum thermal flux to power ratio, which is a desirable characteristic of a modern research reactor. This design, for a 10 MW power, was analyzed using MCNP, ORI...

The 250kW TRIGA Mark II research reactor, Vienna, is equipped with experimental facilities inside and outside the reactor core. Outside the core, there are four beam tubes (three radial and one tangential beam tube), a thermal column and a neutron radiography collimator, supplying neutrons for irradiation experiments. These experiments include neutron radiography, neutron tomography, neutron ac...

Modern technical computing environments, such as Mathematica or Matlab, provide powerful tools and techniques for research reactor analysis combined with advanced graphical user interfaces. In addition, reactor calculations can now be efficiently supported by neutronics codes based on the Monte Carlo method due to the dramatic increase of computer performance in recent years. In particular for ...

Most HWRs currently use natural uranium fuel. Using enriched uranium fuel results in a significant improvement in fuel cycle costs and uranium utilization. On the other hand, reactivity changes of HWRs over the full range of operating conditions from cold shutdown to full power are small. This reduces the required reactivity worth of control devices and minimizes local flux distribution perturb...

BACKGROUND Obtaining high quality images in Single Photon Emission Tomography (SPECT) device  is the most important goal in nuclear medicine. Because if image quality is low, the possibility of making a mistake in diagnosing and treating the patient will rise. Studying effective factors in spatial resolution of imaging systems is thus deemed to be vital. One of the most important factors in SPE...

Medical isotopes can be produced by reactors and accelerators [1]. For certain isotopes there could be an advantage to a certain production method. For example; in some cases production via the ( ,n) or ( ,p) reaction has advantages that include high production yield [2] and production in a matrix that simplifies chemical separation of the desired isotope. To maximize isotope production, a high...