Inorganic–polymer
composites have become promising materials to be processed by printing
technologies because of their unique properties that allow the fabrication
of flexible wearable electronics at reduced manufacturing costs. In
the present work, a complete methodological process of assembling
a flexible microthermoelectric generator based on inorganic−polymer
materials is presented. The used microparticles were prepared by a
top-down approach beginning with a previously prepared material by
solid-state reaction and later scaled down through the use of ball
milling. It was found that the necessity to proceed with a chemical
treatment with HCl to reduce Bi2O3 present on
the surface of the microparticle leads to a power factor (PF) of 2.29
μW K–2 m–1, which is two
times higher than that of the untreated sample. On the fabrication
of flexible inorganic–organic thermoelectric thick films based
on Bi2Te3 microparticles (<50 μm) and
the poly(vinyl alcohol) (PVA) polymer with different thicknesses ranging
from 11 to 265 μm and with different Bi2Te3 weight percentages (wt %), we found that PVA allowed achieving a
homogeneous dispersion of the parent inorganic thermoelectric materials,
while still maintaining their high performance. The best produced
ink was obtained with 25 wt % of PVA and 75 wt % of chemically treated
Bi2Te3 micropowder with a Seebeck coefficient
of −166 μV K–1 and a PF of 0.04 μW
K–2 m–1. For this optimized concentration,
a flexible thermoelectric device was fabricated using n-type thermoelectric
inks, which constitutes a major advantage to be applied in printing
techniques because of their low curing temperature. The device architecture
was composed of 10 stripes with 0.2 × 2.5 cm2 each
in a one-leg configuration. This prototype yielded a power output
up to ∼9 μW cm–2 with a 46 K temperature
gradient (ΔT), and the results were combined
with numerical simulations showing a good match between the experimental
and the numerical results. The thermoelectric devices studied in this
work offer easy fabrication, flexibility, and an attractive thermoelectric
output for specific power requirements such as for environmental health
monitoring.
We study iteration maps of recurrence relations arising from mutation periodic quivers of arbitrary period. Combining tools from cluster algebra theory and (pre)symplectic geometry, we show that these cluster iteration maps can be reduced to symplectic maps on a lower dimensional submanifold, provided the matrix representing the quiver is singular. The reduced iteration map is explicitly computed for several new periodic quivers. MSC 2010: 53D20; 13F60, 37J10, 65Q30.
There is extensive use of the 20-item Toronto Alexithymia Scale (TAS-20) in research and clinical practice in anorexia nervosa (AN), though it is not empirically established in this population. This study aims to examine the factorial validity of the TAS-20 in a Portuguese AN sample (N = 125), testing four different models (ranging from 1 to 4 factors) that were identified in critical examination of existing factor analytic studies. Results of confirmatory factor analysis (CFA) suggested that the three-factor solution, measuring difficulty identifying (DIF) and describing feelings (DDF), and externally oriented thinking (EOT), was the best fitting model. The quality of measurement improves if two EOT items (16 and 18) are eliminated. Internal consistency of EOT was low and decreased with age. The results provide support for the factorial validity of the TAS-20 in AN. Nevertheless, the measurement of EOT requires some caution and may be problematic in AN adolescents.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.