Can disorder induce a finite thermal conductivity in 1D lattices?

We study heat conduction in one dimensional mass disordered harmonic and anharmonic lattices. It is found that the thermal conductivity $\kappa$ of the disordered anharmonic lattice is finite at low temperature, whereas it diverges as $\kappa \sim N^{0.43}$ at high temperature. Moreover, we demonstrate that a unique nonequilibrium stationary state in the disordered harmonic lattice does not exist at all.Comment: 4 pages with 4 eps figure

Application of airborne photogrammetry for the visualisation and assessment of contamination migration arising from a Fukushima waste storage facility

Airborne systems such as lightweight and highly portable unmanned aerial vehicles (UAVs) are becoming increasingly widespread in both academia and industry - with an ever-increasing range of applications, including (but not limited to), air quality sampling, wildlife monitoring and land-use mapping.In this work, high-resolution airborne photogrammetry obtained using a multi-rotor system operating at low survey altitudes, is combined with ground-based radiation mapping data acquired at an interim storage facility for wastes removed as part of the large-scale Fukushima clean-up program. The investigation aimed to assess the extent to which the remediation program at a specific site has contained the stored contaminants, as well as present a new methodology for rapidly surveying radiological sites globally. From the three-dimensional rendering of the site of interest, it was possible to not only generate a powerful graphic confirming the elevated radiological intensity existing at the location of the waste bags, but also to also illustrate the downslope movement of contamination due to species leakage from the large 1m3 storage bags. The entire survey took less than 1 h to perform, and was subsequently post-processed using graphical information software to obtain the renderings. The conclusions within this study not only highlight the usefulness of incorporating three-dimensional renderings within radiation mapping protocols, but also conclude that current methods of monitoring these storage facilities in the long term could be improved through the integration of UAVs within the standard protocol

Population structure and diversity in Valencia peanut germplasm collection

Valencia peanuts [Arachis hypogaea L. subsp. fastigiata Waldron var. fastigiata (Waldron) Krapov. & W. C. Greg.] are well known for their in-shell market value. Assessment of genetic diversity is key to the success of developing improved cultivars with desirable agronomic and quality traits. Seventy-eight U.S. Valencia core collection accessions together with 36 Valencia accessions representing the global peanut mini-core collection were used to study population structure and diversity and to identify genetically diverse Valencia germplasm for use in peanut breeding. Fifty-two simple sequence repeats loci amplifi ed 683 alleles, with an average of 13 alleles per locus. The mean polymorphism information content and gene diversity, respectively, were 0.270 and 0.335. The pairwise genetic distance ranged from 0.143 to 0.474, with an average of 0.631. Neighbor-joining clustering, principal coordinate analysis, and STRUCTURE analysis consistently separated the Valencia germplasm into fi ve clusters with two distinct major groups. The fi rst major group consisted of genotypes from South America (64%) with few accessions from Africa, North America, Caribbean, and European regions. The second group consisted of accessions mostly from diverse regions of Africa, North and South America, Asia, and the Caribbean. However, the structuring was not related to the geographic origin and several admixtures were observed. The information generated in this study and phenotyping of this material for biotic and abiotic stress responses and yield-quality traits will facilitate selection of trait-specifi c, genetically diverse parents for developing Valencia peanut cultivars with a broad genetic base

Anomalous Heat Conduction and Anomalous Diffusion in Low Dimensional Nanoscale Systems

Thermal transport is an important energy transfer process in nature. Phonon is the major energy carrier for heat in semiconductor and dielectric materials. In analogy to Ohm's law for electrical conductivity, Fourier's law is a fundamental rule of heat transfer in solids. It states that the thermal conductivity is independent of sample scale and geometry. Although Fourier's law has received great success in describing macroscopic thermal transport in the past two hundreds years, its validity in low dimensional systems is still an open question. Here we give a brief review of the recent developments in experimental, theoretical and numerical studies of heat transport in low dimensional systems, include lattice models, nanowires, nanotubes and graphenes. We will demonstrate that the phonon transports in low dimensional systems super-diffusively, which leads to a size dependent thermal conductivity. In other words, Fourier's law is breakdown in low dimensional structures