University of Crete

About: University of Crete is a education organization based out in Rethymno, Greece. It is known for research contribution in the topics: Population & Galaxy. The organization has 8681 authors who have published 21684 publications receiving 709078 citations. The organization is also known as: Panepistimio Kritis.

Unusual Phonon Heat Transport in α -RuCl 3 : Strong Spin-Phonon Scattering and Field-Induced Spin Gap

Abstract: The honeycomb Kitaev-Heisenberg model is a source of a quantum spin liquid with Majorana fermions and gauge flux excitations as fractional quasiparticles. Here we unveil the highly unusual low-temperature heat conductivity $\ensuremath{\kappa}$ of $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{RuCl}}_{3}$, a prime candidate for realizing such physics: beyond a magnetic field of ${B}_{c}\ensuremath{\approx}7.5\text{ }\text{ }\mathrm{T}$, $\ensuremath{\kappa}$ increases by about one order of magnitude, both for in-plane as well as out-of-plane transport. This clarifies the unusual magnetic field dependence unambiguously to be the result of severe scattering of phonons off putative Kitaev-Heisenberg excitations in combination with a drastic field-induced change of the magnetic excitation spectrum. In particular, an unexpected, large energy gap arises, which increases linearly with the magnetic field, reaching remarkable $\ensuremath{\hbar}{\ensuremath{\omega}}_{0}/{k}_{B}\ensuremath{\approx}50\text{ }\text{ }\mathrm{K}$ at 18 T.

Ochratoxin A concentrations in Greek domestic wines and dried vine fruits

Abstract: A survey for the presence of ochratoxin A (OTA) was conducted from 1995 to 1999 on 268 locally produced commercial wines, and on 81 samples of domestic dried vine fruits (currants and sultanas) collected between 1998 and 2000 from sites of primary storage and processing. The OTA concentration in red dry wines (n = 104, median = 0.09 μg l-1) was not significantly different from that for white (n = 118, median = 0.06 μg l-1) and rose (n = 20, median = 0.08 μg l-1) wines. Eighteen samples of dessert wines (sweet, semi-sweet, semi-dry) and eight samples of retsina wine showed larger OTA concentrations with medians of 0.33 and 0.27 μg l-1, respectively. Our data indicate that the geographic region of origin influences OTA contamination for the red dry wines. In fact, a trend of increasing OTA contamination was observed for red wines from northern to southern Greece. Regarding the OTA levels in dried vine fruits, sultanas (n = 27, median = 0.6 μg kg-1) were less contaminated than currants (n = 54, median = 1.3 ...

Selective capture of hexavalent chromium from an anion-exchange column of metal organic resin–alginic acid composite

Abstract: We report an anion exchange composite material based on a protonated amine-functionalized metal–organic framework, denoted Metal Organic Resin-1 (MOR-1), and alginic acid (HA). MOR-1–HA material shows an exceptional capability to rapidly and selectively sorb Cr(VI) under a variety of conditions and in the presence of several competitive ions. The selectivity of MOR-1–HA for Cr(VI) is shown to be the result of strong O3CrVI⋯NH2 interactions. The composite sorbent can be successfully utilized in an ion-exchange column, in contrast to pristine MOR-1 which forms fine suspensions in water passing through the column. Remarkably, an ion exchange column with only 1% wt MOR-1–HA and 99% wt sand (an inert and inexpensive material) is capable of reducing moderate and trace Cr(VI) concentrations to well below the acceptable safety limits for water. The relatively low cost of MOR-1–HA/sand column and its high regeneration capability and reusability make it particularly attractive for application in the remediation of Cr(VI)-bearing industrial waste.