249 research outputs found
Refined Structure of Metastable Ice XVII from Neutron Diffraction Measurements
The structure of the recently identified metastable ice XVII, obtained by
release of hydrogen from the C DO-H compound (filled ice), has been
accurately measured by neutron powder diffraction. The diffraction pattern is
indexed with a hexagonal cell and can be refined with space group so
to obtain accurate values of the oxygen and deuterium positions. The values of
the lattice constants at three temperatures between 25 to 100 K are reported,
and their behavior is compared with that of ice Ih. Ice XVII is a porous solid
that, if exposed to H gas, may adsorb a substantial amount of it.
Monitoring this effect at a constant temperature of 50 K, we have observed that
the two lattice constants show opposite behavior, increases and
decreases, with the volume showing a linear increase. At temperatures higher
than 130 K the metastability of this form of porous ice is lost and the sample
transforms into ice Ih
A sustainable approach towards the retrofit of the public housing building stock: Energy-architectural experimental and numerical analysis
Nowadays, energy retrofit interventions on the existing building stock are of paramount importance towards energy consumption and emissions reductions in the construction sector. Such interventions are also crucial in the view of increasing cities resilience with respect to the intensification of frequent extreme weather events, such as cold spells and heatwaves. Indeed, a wide portion of our cities is dated and lacking with respect to performances. These are the motivations behind the proposed sustainable approach, which deals with the environmental perspective, but also with social and economic ones, by proposing the retrofit of the Public Residential Building stock (Edilizia Residenziale Pubblica, ERP). The objective is to improve the energy performance of ERP stock by means of construction materials coming from local km0 agricultural waste and by-products. The research was conducted by means of in field and numerical analyses of the energy performances of a relevant case study building. Different layers of bio-based, recycled construction materials for the envelope were tested with respect to their efficacy in improving the energy performance of a case study building. The results demonstrate that the most performing envelope solutions and their combination are able to reduce up to 36% of the yearly energy consumption for heating
- …