ALBERT

Description: Metal–ceramic nanocomposite films for solar absorbers have been obtained by electro-deposition. This coating technique uses a mixed solution of nickel nanoparticles and sub-micron alumina particles. The relative ratio of Ni-to-Al in these films is varied by tuning the concentration of nickel and alumina particles in the starting solution. Three films with different Ni/Al ratio have been prepared and characterized with X-ray photo-electron spectroscopy and scanning electron microscope. Even in absence of any heat treatment, significant amount of nickel in metallic state has been found in all three samples.

Description: The results and considerations on one self-consumption photovoltaic installation with net balance in Granada (South of Spain) are presented and discussed in this paper. The use of the building (one faculty) makes it optimal for this kind of consumption. Finally, the potential benefits and problems of self-consumption with net balance are presented.

Description: Under transient climatic conditions, solar water heaters using heat pipes are more effective at capturing incident solar radiation than other equivalent sized solar water heaters. The cost must be reduced to improve uptake of such systems. To investigate two methods were considered by this study: thermosyphon fluid flow and reflective concentrators. A physical reconfigurable laboratory model of the manifold and associated condensers of a heat-pipe-evacuated tube system were fabricated; fluid circulation was via thermosyphonic action, particle imaging velocimetry derived velocity maps and the use of concentrators was simulated. When condenser spacing was doubled, the Nusselt number increased by 43%, the velocity by 55% but the heat transfer efficiency of the model manifold decreased by 9%. Potential annual energy savings of 10 207 GWh could be realized if such systems could be successfully fabricated.

Description: Sensitive instruments like strainmeters and tiltmeters are necessary for measuring slowly varying low amplitude Earth deformations. Nonetheless, laser and fibre interferometers are particularly suitable for interrogating such instruments due to their extreme precision and accuracy. In this paper, a practical design of a simple pendulum borehole tiltmeter based on laser fibre interferometric displacement sensors is presented. A prototype instrument has been constructed using welded borosilicate with a pendulum length of 0.85 m resulting in a main resonance frequency of 0.6 Hz. By implementing three coplanar extrinsic fibre Fabry-Perot interferometric probes and appropriate signal filtering, our instrument provides tilt measurements that are insensitive to parasitic deformations caused by temperature and pressure variations. This prototype has been installed in an underground facility (Rustrel, France) where results show accurate measurements of Earth strains derived from Earth and ocean tides, local hydrologic effects, as well as local and remote earthquakes. The large dynamic range and the high sensitivity of this tiltmeter render it an invaluable tool for numerous geophysical applications such as transient fault motion, volcanic strain and reservoir monitoring.

Description: We review the theory of the Earth's elastic and gravitational response to a surface disk load. The solutions for displacement of the surface and the geoid are developed using expansions of Legendre polynomials, their derivatives and the load Love numbers. We provide a matlab  function called diskload that computes the solutions for both uncompensated and compensated disk loads. In order to numerically implement the Legendre expansions, it is necessary to choose a harmonic degree, n max , at which to truncate the series used to construct the solutions. We present a rule of thumb (ROT) for choosing an appropriate value of n max , describe the consequences of truncating the expansions prematurely and provide a means to judiciously violate the ROT when that becomes a practical necessity.

Description: The article describes the innovative solutions of power, heating and cooling generation utilizing low- or medium-grade heat sources. The proposed technology based on the well-known irreversible Brayton cycle and the revolutionary Maisotsenko cycle (M-cycle) operates at atmospheric or sub-atmospheric pressures. Such energetic systems are simple and reliable and utilize moisture-saturated air as a working fluid. The ejector replacing the mechanical compressor in the Brayton cycle system allows increasing the cycle work by three to five times at the constant airflow. At the same time, the utilized heat serves for simultaneous heating and cooling production that makes the system economically viable and environmentally friendly with the increased integral performance. For system's performance improvement, the schematic and the cycle were upgraded allowing the off-the-shelf components to be employed and replace the electrically driven fan with fluidic jet-fan that served for energy saving of the innovative turbo-ejector system operation.

Description: In the present work we illustrate a new local inversion algorithm to retrieve the Moho depth from GOCE (Gravity field and steady-state Ocean Circulation Explorer) gravity field. In details the proposed procedure can be divided into two main steps: the first one consists in recognizing and isolating the different geological provinces in the study area by exploiting information coming from the GOCE global gravity field model. Once the main geological provinces are defined, a function relating the crust density of each province with depth is built and used to reduce the data. The gravitational effects of sediments, topography, bathymetry and upper mantle are also removed. In the second step the residual gravitational field is inverted to retrieve the Moho depth and some information on the crustal density. In particular, the clustering of geological province is performed by means of an automatic Bayesian classification algorithm while the inversion of GOCE residual field is performed by adapting the global algorithm developed in the framework of the GEMMA project to the local scale. The procedure, based on an iterative Wiener filter, allows to compute the Moho depth considering lateral as well as radial variations of crustal density. The algorithm has been applied to the fifth release of GOCE time-wise global gravity field model to infer information on the crustal structure in the Western Balkan area, that is, the region laying between Bulgaria and the Adriatic Sea. This region is one of the most complex and active, from the tectonic point of view, in the whole Europe and it is characterized by the presence of the Alpine-Himalayan orogenic belt, formed by the collision between the African and Eurasian plates, and by the opening of the Pannonian Basin. Results show a good agreement between the obtained geological provinces with the actual knowledge on the region. The resulting Moho depth ranges between about 20 km beneath the Adriatic Sea and 45 km in the Dinarides. Comparisons with available seismic data show differences smaller than 1 km (standard deviation).

Description: With the development of the energy demands, solar energy medium-temperature applications (〉80°C) for refrigeration, building heating, seawater desalination, thermal power generation etc. has become popular research fields. The article presents an investigation on a static low-concentration evacuated tube (LCET) solar collector for medium-temperature applications. Ray trace outcome at the incident angles between 0 and 60° shows that the average optical efficiency can reach 76.9%. The experimental testing was conducted in the medium temperature range of 80 and 140°C which indicates the instantaneous thermal efficiency is still larger than about 30.0%, and the instantaneous exergetic efficiency is 〉5.92%. The results comprehensively indicate the good performance of LCET solar collector for medium-temperature applications.

Description: The urban forest is generally decreasing in areal extent. At the same time, human population is urbanizing and urban areal extent per capita is increasing. Eighty percent of North Americans are now living in urbanized areas. Urban forests directly affect quality of life for residents of cities via the ecosystem services and psychosocial restoration they provide. The urban forest canopy is a key component of reducing the urban heat island, slowing stormwater runoff and making urban environments more efficient and livable. Municipalities in North America are reacting to concerns about urbanization and economic trends by permitting an increasing number of compact developments that may conflict with beneficial Green Infrastructure. Compact development may also present challenges to solar access for solar power generation. This paper identifies and illustrates key strategies to increase urban forest cover and decrease infrastructure conflicts by implementing given innovative design details, detailing specific zoning and code language, and providing best practices from multiple disciplines. These strategies to increase urban forest canopy cover frame a coherent set of ideas to decrease the effects of the urban heat island, increase solar power generation and improve urban quality of life in cities.

Description: Normal mode treatments of the Earth's body tide response were developed in the 1980s to account for the effects of Earth rotation, ellipticity, anelasticity and resonant excitation within the diurnal band. Recent space-geodetic measurements of the Earth's crustal displacement in response to luni-solar tidal forcings have revealed geographical variations that are indicative of aspherical deep mantle structure, thus providing a novel data set for constraining deep mantle elastic and density structure. In light of this, we make use of advances in seismic free oscillation literature to develop a new, generalized normal mode theory for the tidal response within the semi-diurnal and long-period tidal band. Our theory involves a perturbation method that permits an efficient calculation of the impact of aspherical structure on the tidal response. In addition, we introduce a normal mode treatment of anelasticity that is distinct from both earlier work in body tides and the approach adopted in free oscillation seismology. We present several simple numerical applications of the new theory. First, we compute the tidal response of a spherically symmetric, non-rotating, elastic and isotropic Earth model and demonstrate that our predictions match those based on standard Love number theory. Second, we compute perturbations to this response associated with mantle anelasticity and demonstrate that the usual set of seismic modes adopted for this purpose must be augmented by a family of relaxation modes to accurately capture the full effect of anelasticity on the body tide response. Finally, we explore aspherical effects including rotation and we benchmark results from several illustrative case studies of aspherical Earth structure against independent finite-volume numerical calculations of the semi-diurnal body tide response. These tests confirm the accuracy of the normal mode methodology to at least the level of numerical error in the finite-volume predictions. They also demonstrate that full coupling of normal modes, rather than group coupling, is necessary for accurate predictions of the body tide response.