Revista Cubana de Física

Using the concept of information distance derived from Kolmogorov randomness, we study damage spreading for elementary cellular automata acting on a one-dimensional lattice. In contrast to previous definitions of the Lyapunov exponent based on Hamming distance, the new magnitude allows a better clustering of chaotic rules. Thecombined use of the Lyapunov exponent, Hamming, and information distance-based, results in a more robust characterization of cellular automata behavior. An exten-sion of the type analysis shown can be directly made to other one-dimensional time and space discrete dynamical systems.

Molecular simulations have been useful tools in the research of the host-guest interactions in clays. It has been possible due to the implementation of appropriate force fields to simulate clays, as the CLAYFF. It uses the SPC potential to reproduce the water interactions. However, this is a limitation when combined with the most used organic force fields, AMBER and CHARMM, that use the TIP3P water potential. In the present paper, molecular dynamics simulations of the water-clay model system were done using a combination of CLAYFF with SPC and TIP3P water force fields in order to validate the use of TIP3P water model with the CLAYFF. The results show very good agreement between radial distribution functions and diffusion coefficients using both water potentials combined with CLAYFF. This fact opens the possibility of using this clay force field with the CHARMM and AMBER force fields.

 In this work, we evaluated the use of laser-induced breakdown spectroscopy (LIBS) coupled with chemometric methods as a fast and simple technique for identifying diseased tissue in prostate cancer samples. The experimental setup consisted of a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser in a burst-mode regime, with differing time delays for the spectrometer readings. To improve classification accuracy, principal component analysis (PCA) was coupled with neural analysis (NA), achieving a high identification accuracy of 97%. It can be concluded that LIBS has the potential to serve as a technique for the detection and diagnosis of human prostate cancer.  

In recent years, the design of new prototypes of small modular reactors has generated a growing interest in the international scientific community. Their applications and versatility make them an attractive option among candidates considered in generation III+ and IV. The use of TRi-structural ISOtropic fuel (TRISO) in integral pressurized water reactors (iPWR) constitutes a challenge to achieve extended fuel cycles. To obtain high proliferation resistance, extended fuel cycles for the iPWRs have been proposed. Obtaining such a large cycle length, using low fuel enrichment, without shuffle, and with a relatively small core size, is a challenge for the neutronic design of the reactor core. Previous works have analyzed the characteristics of an iPWR using TRISO fuel with a power of 25 MWt. In this work, a full-core neutronic computational model based in SERPENT code was developed, allowing to describe the performance of the proposed reactor core configurations. The core neutronic update is made with the aim of increasing the thermal power. The radial power distributions, fuel cycle length and other parameters for the different variants are analyzed and compared.

The use of non-conventional fuels in traditional Light Water Reactors (LWR) improves their performance in safety, as well as the characteristics of the fuel cycle. Using TRISO (Tristructural Isotropic) or SCF (Spherical Cermet Fuel) particles in a PWR-type (Pressurized Water Reactor) SMR (Small Modular Reactor) core enhances the proliferation resistance, fission products retention and greatly simplifies safeguards oversight. It has been shown that using TRISO fuel at low coolant temperatures can cause swelling induced by irradiation in the SiC barrier, so the use of another type of fuel without this issue and with equivalent neutronic performance to that obtained when TRISO fuel is used, may be more suitable for use in these types of plants. This work compares the neutronic performance of a PWR-type SMR core, using SCF particles with the same core using TRISO fuel in terms of burnup, spectrum, and radial power distributions. TRISO fuel has better multiplicative properties than SCF particles. Using SCF particles, the cycle duration decreases by approximately 8%, a difference that is lower when the fuel mass is increased. The differences in the spectrum are higher in the thermal zone. The radial power distributions at the beginning of the cycle and at the end of the cycle are similar. Pu-239 production is higher when TRISO fuel is used.