Necklace theory on Flower Constellations

Theory of Flower Constellations has been improved with the 2-D and 3-D Lattice Flower Constellations. However, placing a satellite in each admissible location is not an optimal way to design a constellation. The necklace theory considers constellations whose satellites are subsets of the satellites of a Lattice Flower Constellation, keeping all its symmetries, in order to reduce the cost of the mission. Mathematically, these subsets are parameterized by necklaces (describing which satellites in the first orbit of the underlying constellation we keep), and a shifting parameter that controls the phasing between subsequent orbits

A case of Service Learning and Research Engagement in pre-service teachers\u2019 education

Service Learning (SL) represents one experiential methodology largely adopted in Higher Education because it is able to develop both academic and soft skills, in particular civic and reflective ones. SL has gained the attention of teacher educators in the U.S. since the 1990s.. Many scholars have underlined how SL is useful to enhance elements essential for future teachers as (a) the development of teaching skills, (b) reflective skills; (c) a more complex vision of teaching and learning practices; (d) an attention to special need children and children coming from different social and ethnical backgrounds; (e) a human service-oriented vision of teaching; and in building a community of practice. Moreover, SL is particularly suitable in Teacher Education because it connects pre-service with in-service teachers, as requested by the European Commission (2014); from this relationship, it involves the whole community in a process of transformation

Active Rules for Runtime Adaptivity Management

The trend over the last years clearly shows that modern Web development is evolving from traditional, HTML-based Web sites to fullfledged, complex Web applications, also equipped with active and/or adaptive application features. While this evolution unavoidably implies higher development costs and times, such implications are contrasted by the dynamics of the modern Web, which demands for even faster application development and evolution cycles. In this paper we address the above problem by focusing on the case of adaptive Web applications. We illustrate an ECA rule-based approach, intended to facilitate the management and evolution of adaptive application features. For this purpose, we stress the importance of decoupling the active logic (i.e. the adaptivity rules) from the execution of the actual application by means of a decoupled rule engine that is able to capture events and to autonomously enact adaptivity actions

Applications of nano- and mesoporous gold in electrodes and electrochemical sensors

A nano- or mesoporous sponge of Au is formed when the intermetallic compound AuAl2 is de-alloyed with NaOH. The large specific surface area of the sponge, and the unique surface chemical properties of Au indicate that this porous material might usefully serve as an electrode in capacitive sensors or other specialized electrochemical cells. Results for some prototype sensor and energy storage systems are presented, and methods of controlling the nature of the porosity presented. © 2006 IEEE

THE CALCIUM LOOPING CYCLE STUDY FOR CAPTURING CARBON DIOXIDE APPLIED TO THE ENERGY GENERATION

The calcium looping process (Ca-L) is a promising technology to reduce of the carbon dioxide (CO2) emissions when applied in energy generation systems. Ca-based materials (usually limestone) are used in this process as CO2 sorbents. Thus, the CO2 capture occurs by the reversible reaction between calcium oxide (CaO) and CO2, resulting in the calcium carbonate form (CaCO3). Compared to other technologies applied to carbon sequestration process, the Ca-L offers additional advantages such: the use of fluidized bed technology that is already well established; this process occurs at high temperature, and the excess of heat generated can be recovered; the cost of limestone sorbents is low because of its wide availability. However, in the applying the Ca-L process is essential to understand the mechanism and the effect of partial pressure of CO2 in both, calcination and carbonation processes; to investigate the effect of sintering and to evaluate the sorbent activity decay. In this paper, empirical technique such as thermogravimetry is applied to investigate the reactivity of dolomite as CO2 sorbent. The effect of CO2 high concentrations in both calcination/carbonation processes is also investigated

STUDY OF THERMAL DECOMPOSITION AND IGNITION TEMPERATURE OF BAGASSE, COAL AND THEIR BLENDS

In Brazil, due to its availability, sugar cane bagasse has a high potential for power generation. The knowledge of ignition behavior, as well as the knowledge of the chemical kinetics, in of fuels combustion process is important features in boilers projects and in the stability of the combustion process control. The aim of this study is to investigate the thermal behavior of sugar cane bagasse, coal and their blends. The methodology proposed by Tognotti et al. (1985) was applied to determine the ignition temperature for all samples. Ignition temperatures were 256oC for neat bagasse and 427oC for neat coal, and 275oC for both blends (50-50% and 25-75%). The Model-Free Kinetics was applied to determine the apparent activation energy (Eα) of the thermal decomposition of sugar cane bagasse. For the two major events of mass loss of bagasse which correspond to the thermal decomposition of organic matter (mainly hemicellulose, cellulose and lignin), average values of Eα were obtained for both combustion and pyrolysis processes. In synthetic air atmosphere, the Eα were 170.8±26.3 kJ⋅mol-1 and 277.8±58.6 kJ⋅mol-1, while in nitrogen atmosphere, the Eα were 185.0 ± 11.4 kJ⋅mol-1 and 82.1±44.4 kJ⋅mol-1. The results obtained can be explained by synergistic effects when both bagasse and coal were blended, changing the fuel reactivity

Carbonic nanoparticles and C-S-H insertion into cementitious nanocomposite

Use of nanomaterials in cementitious nanocomposites is a possibility to improving mechanical properties as well as increased durability. In this research the insertion of multi-walled carbon nanotubes (MWCNT) and particles of Calcium Silicate Hydrate (C-S-H) with Ca/Si=0.8 and Ca/Si=1.2 ratios were used in microconcrete specimens. The effects on the compressive and tensile strength were tested, besides analysis of the porous structure by mercury intrusion, as well as the microstructure by scanning electron microscopy. Nanocomposites were produced by varying NTCPM insertions at 0.1% and 0.2% and C-S-H inserts at 1% and 2%, all of them based on cement mass. The results showed that the nanocomposites with C-S-H insertion with Ca/Si=0.8 ratio were the least porous and presented the highest tensile and compressive strengths, reaching strength increases in the order of 30% compared to the control material because C-S-H insertion with Ca/Si=0.8 ratio is reactive and causes reduction of the total porosity