Linear sampling method for identifying cavities in a heat conductor

We consider an inverse problem of identifying the unknown cavities in a heat conductor. Using the Neumann-to-Dirichlet map as an input data, we develop a linear sampling type method for the heat equation. A new feature is that there is a freedom to choose the time variable, which suggests that we have more data than the linear sampling methods for the inverse boundary value problem associated with EIT and inverse scattering problem with near field data

Exclusion Statistics of Quasiparticles in Condensed States of Composite Fermion Excitations

The exclusion statistics of quasiparticles is found at any level of the hierarchy of condensed states of composite fermion excitations (for which experimental indications have recently been found). The hierarchy of condensed states of excitations in boson Jain states is introduced and the statistics of quasiparticles is found. The quantum Hall states of charged $\alpha$-anyons ($\alpha$ -- the exclusion statistics parameter) can be described as incompressible states of $(\alpha+2p)$-anyons ($2p$ -- an even number).Comment: 4 page

TCR cross-reactivity and allorecognition: new insights into the immunogenetics of allorecognition

Alloreactive T cells are core mediators of graft rejection and are a potent barrier to transplantation tolerance. It was previously unclear how T cells educated in the recipient thymus could recognize allogeneic HLA molecules. Recently it was shown that both naïve and memory CD4+ and CD8+ T cells are frequently cross-reactive against allogeneic HLA molecules and that this allorecognition exhibits exquisite peptide and HLA specificity and is dependent on both public and private specificities of the T cell receptor. In this review we highlight new insights gained into the immunogenetics of allorecognition, with particular emphasis on how viral infection and vaccination may specifically activate allo-HLA reactive T cells. We also briefly discuss the potential for virus-specific T cell infusions to produce GvHD. The progress made in understanding the molecular basis of allograft rejection will hopefully be translated into improved allograft function and/or survival, and eventually tolerance induction

Additive manufacturing of composite materials and functionally graded structures using selective heat melting technique

The feasibility of using selective heat melting (SHM) to fabricate composite materials and functionally graded structures was investigated. We report, for the first time, the successful 3D printing of copper (Cu)-polyethylene (PE) composite, iron (Fe)-polyethylene (PE) composite and functionally graded CuO foams using the SHM technique. It was found that a low feed rate, high airflow rate and high airflow temperature were required for efficient delivery of heat from the emitted hot air to the powder bed, so that the PE binder particles can melt and form dense composites with smooth surfaces. The best mechanical properties were exhibited by composites with 80 vol.% PE, as lower PE concentrations led to deficient binding of the metal particles, while higher PE concentrations meant that very few metal particles were available to strengthen the composite. The strength exhibited by Cu-PE composites was comparable to engineering plastics such as polycarbonate, with the added advantage of being electrically conductive. The average conductivity of the samples, 0.152 ± 0.28 S/m, was on par with physically cross-linked graphene assemblies. By subjecting a Cu-PE composite, with Cu concentration graded from 10 vol.% to 30 vol.%, to a high temperature debinding and sintering treatment in air, CuO foam with graded porosity can be obtained. This CuO foam was observed to fail in a layer-by-layer manner under mechanical compression, which is a characteristic of functionally graded materials. Our study shows that, compared to existing 3D printing techniques, SHM can be cheaper, have wider material compatibility, occupy a smaller footprint and potentially induce less residual stresses in the fabricated parts. Therefore, it could be a valuable complement to current additive manufacturing techniques for fabricating mechanically strong composite materials and functionally graded structures.Accepted versio