Search results for "Cooling"
showing 10 items of 470 documents
Synthesis of Peroxyapatite by Hydrothermal Processing
2014
Peroxide ions in apatite provides an additional resource for imparting an antibacterial capability in apatite. A hydrothermal process has been developed for including peroxide ions into the apatite lattice. Three oxygen generation compounds, hydrogen peroxide, ammonium persulphate and paracetic acid were investigated for peroxyapatite generation. Hydrogen peroxide provides the highest peroxide containing apatite. Both the oxygen generation and the apatite lattice formation represented the two critical factors for producing peroxyapatite. Unlike with high temperature processing, the cooling rate did not influence the retained peroxide content. This new process provides a building block for i…
Correlation spectroscopy in molten and supercooled antimony trichloride.
1990
Correlation spectroscopy measurements performed on molten and supercooled antimony trichloride with the homodyne technique show correlation functions that have a nonexponential behavior. Two well-defined distributions of correlation times can be observed in different temporal regions. This behavior is discussed in terms of a structural relaxation of clusters dynamically formed by intermolecular and interchain bonds. The Arrhenius plot of these correlation times shows a linear behavior with the same activation energy for both. In contrast, the activation energy of shear viscosity has a different value, showing that the processes determining the temperature behavior of \ensuremath{\tau} and $…
Analytical studies of the Sirocco room of Villa Naselli-Ambleri: A XVI century passive cooling structure in Palermo (Sicily)
2015
Abstract This work focuses on a passive cooling architecture particularly popular from the Renaissance in Palermo area, as building sumptuous suburban villas became a real hobby for the Sicilian aristocracy. A Sirocco room is an artificial subterranean construction, built close to a water spring in order to reproduce the pleasant conditions of freshness that could be experienced in a natural cavern. In these places, nobles used to spend their time with friends to escape from the hot summer. The room of Villa Naselli-Ambleri is nowadays the best preserved in Palermo thanks to its owners’ conservation care and it is unique for its cooling operating principle. The above-mentioned consideration…
Paleoclimate variability during the Blake geomagnetic excursion (MIS 5d) deduced from a speleothem record
2014
To evaluate possible connections between climate and the Earth's magnetic field, we examine paleoclimate proxies in a stalagmite (PA-8) recording the Blake excursion (∼112–∼116.4 ka) from Cobre cave (N Spain). Trace element, δ13C, δ18O, δ234U, fluorescent lamination, growth rate, and paleomagnetic records were synchronized using a floating lamina-counted chronology constrained by U–Th dates, providing a high-resolution multi-proxy paleoclimate record for MIS 5d. The alpine cave setting and the combination of proxies contributed to improve the confidence of the paleoclimatic interpretation. Periods of relatively warm and humid climate likely favored forest development and resulted in high sp…
Potential of Natural Ventilation and Vegetation for Achieving Low-Energy Tall Buildings in Tropical Climate: An Overview
2019
Climate change and rise in urban temperatures have further increased the cooling load demands for tall buildings located in hot climatic regions. Cooling loads in tall buildings can be reduced by integrating them with natural ventilation (NV) and building integrated vegetation (BIV) techniques. This study explores the potential of NV and BIV for obtaining low-energy buildings by analyzing ten tall buildings as case studies. Buildings are analyzed for NV, BIV, architecture design parameters, and energy savings. The results show that mixed-mode ventilation is the most commonly employed, and circular building plans have the highest potential for energy savings. Furthermore, the combination of …
Monitoring results and analysis of thermal comfort conditions in experimental buildings for different heating systems and ventilation regimes during …
2017
This paper focuses on the long-term monitoring of thermal comfort and discomfort parameters in five small test buildings equipped with different heating and cooling systems. Calculations of predicted percentage of dissatisfied people (PPD) index and discomfort factors are provided for the room in winter season running three different heating systems – electric heater, air-air heat pump and air-water heat pump, as well as for the summer cooling with split type air conditioning systems. It is shown that the type of heating/cooling system and its working regime has an important impact on thermal comfort conditions in observed room. Recommendations for the optimal operating regimes and choice o…
Architectural technologies for life environment: passive cooling strategies in the architectures of the Mediterranean area.
2020
The Mediterranean area is a highly interesting place where various States, characterised by different people, histories, and cultures face. Reigns, religions, powers, state structures, people, nationalities, etc., everything seems to be extremely different and far. On the contrary, there are some cultural points that are much closer than they officially appear. Indeed, historically, the commercial trades between the various countries have always been highly intense and the Christian and Muslim reigns, even if in a continuous state of conflict, were reciprocally linked by deep (financial) interests. Therefore, that translated in a wide trade of goods that moved on the Mediterranean Sea acros…
Artificial Neural Networks to correlate Hot Deformation Cooling Rate and Deformation Temperature on Continuous Cooling Transformation of 22MnB5 Steel
2016
The 22MnB5 steel is a hot stamping steel developed with the aim to satisfy the increasing request of the automotive industries to apply materials able to guarantee higher passive safety and weight reduction. The hot stamping process is an innovative forming technique in which the deformations are carried out at elevated temperature and allows to achieve high strength components. The experimental characterization of the material response, at different values of the main variables of process, may result both expensive and time consuming, but the mutual effects evaluation of the deformation parameters and the phase transformations are necessary to produce components within the desired properti…
Formation of X-ray emitting stationary shocks in magnetized protostellar jets
2016
X-ray observations of protostellar jets show evidence of strong shocks heating the plasma up to temperatures of a few million degrees. In some cases, the shocked features appear to be stationary. They are interpreted as shock diamonds. We aim at investigating the physics that guides the formation of X-ray emitting stationary shocks in protostellar jets, the role of the magnetic field in determining the location, stability, and detectability in X-rays of these shocks, and the physical properties of the shocked plasma. We performed a set of 2.5-dimensional magnetohydrodynamic numerical simulations modelling supersonic jets ramming into a magnetized medium and explored different configurations…
Aerosol influence on radiative cooling
2011
Aerosol particles have a complex index of refraction and therefore contribute to atmospheric emission and radiative cooling rates. In this paper calculations of the longwave flux divergence within the atmosphere at different heights are presented including water vapour and aerosol particles as emitters and absorbers. The spectral region covered is 5 to 100 microns divided into 23 spectral intervals. The relevant properties of the aerosol particles, the single scattering albedo and the extinction coefficient, were first calculated by Mie-theory and later by an approximation formula with a complex index of refraction given by Volz. The particle growth with relative humidity is also incorporat…