The effect of energy and traffic light labeling on parents purchasing decisions of cereals for their children

Objective: Nutritional labeling systems are considered a tool to fight obesity since they aim to contribute for more informed food choices as well as assist consumers to make healthier nutrition options and in this manner, contribute to a decrease in the obesity rate. This study intends to analyze the effect of different types of labeling systems on parents’ purchasing decisions for their children on a specific product: breakfast cereals. More precisely, how labels affect parents’ perception of healthiness regarding cereals and if the nutritional information has an effect on intended purchases for their children. Participants and methods: We conducted a study with 135 Portuguese parents of children aged 4 to12 years. Parents answered a questionnaire with one of three hypothetical cereals menus. Menus only differed in their nutritional labeling technique: no labels (control group), reference intake labels or traffic light labels. In addition, we conducted 20 face-to-face interviews to a different group of parents in order to perform a recall task. Findings: This paper provides no evidence to suggest that energy labeling or traffic light labeling systems alone were successful in helping parents making healthy purchases of cereals for their children. Therefore, there is the need to promote supplementary policies to encourage the consumption of healthier food and help fight obesity.

VO2 thin films and nanoparticles for energy-saving applications in architectural elements

Vanadium dioxide (VO2) is a promising material with large interest in construction industry and architecture, due to its thermochromic properties. This material may be used to create "smart" coatings that result in improvements in the buildings energy efficiency, by reducing heat exchanges and, consequently, the need for acclimatization. In this work, VO2 thin films and coatings were produced and tested in laboratory, to apply in architectural elements, such as glass, rooftop tiles and exterior paints. Thin films were produced by RF magnetron sputtering and VO2 nanoparticles were obtained through hydrothermal synthesis, aiming to create "smart" windows and tiles, respectively. These coatings have demonstrated the capability to modulate the transmittance of infrared radiation by around 20%. The VO2 nanoparticle coatings were successfully applied on ceramic tiles. The critical temperature was reduced to around 40ºC by tungsten doping. Ultimately, two identical house models were built, in order to test the VO2 coatings, in real atmospheric conditions during one of the hottest months of the year, in Portugal – August.

Assessing initial embodied energy in building structures using LCA methodology

The considerable amount of energy consumed on Earth is a major cause for not achieving sustainable development. Buildings are responsible for the highest worldwide energy consumption, nearly 40%. Strong efforts have been made in what concerns the reduction of buildings operational energy (heating, hot water, ventilation, electricity), since operational energy is so far the highest energy component in a building life cycle. However, as operational energy is being reduced the embodied energy increases. One of the building elements responsible for higher embodied energy consumption is the building structural system. Therefore, the present work is going to study part of embodied energy (initial embodied energy) in building structures using a life cycle assessment methodology, in order to contribute for a greater understanding of embodied energy in buildings structural systems. Initial embodied energy is estimated for a building structure by varying the span and the structural material type. The results are analysed and compared for different stages, and some conclusions are drawn. At the end of this work it was possible to conclude that the building span does not have considerable influence in embodied energy consumption of building structures. However, the structural material type has influence in the overall energetic performance. In fact, with this research it was possible that building structure that requires more initial embodied energy is the steel structure; then the glued laminated timber structure; and finally the concrete structure.

Noble energy oil & Gas

Equity research report

Perylene Diimide acceptors: Fabrication and characterization of electron-only, hole-only devices and solar cells

The thrust towards energy conservation and reduced environmental footprint has fueled intensive research for alternative low cost sources of renewable energy. Organic photovoltaic cells (OPVs), with their low fabrication costs, easy processing and flexibility, represent a possible viable alternative. Perylene diimides (PDIs) are promising electron-acceptor candidates for bulk heterojunction (BHJ) OPVs, as they combine higher absorption and stability with tunable material properties, such as solubility and position of the lowest unoccupied molecular orbital (LUMO) level. A prerequisite for trap free electron transport is for the LUMO to be located at a level deeper than 3.7 eV since electron trapping in organic semiconductors is universal and dominated by a trap level located at 3.6 eV. Although the mostly used fullerene acceptors in polymer:fullerene solar cells feature trap-free electron transport, low optical absorption of fullerene derivatives limits maximum attainable efficiency. In this thesis, we try to get a better understanding of the electronic properties of PDIs, with a focus on charge carrier transport characteristics and the effect of different processing conditions such as annealing temperature and top contact (cathode) material. We report on a commercially available PDI and three PDI derivatives as acceptor materials, and its blends with MEH-PPV (Poly[2-methoxy 5-(2-ethylhexyloxy)-1,4-phenylenevinylene]) and P3HT (Poly(3-hexylthiophene-2,5-diyl)) donor materials in single carrier devices (electron-only and hole-only) and in solar cells. Space-charge limited current measurements and modelling of temperature dependent J-V characteristics confirmed that the electron transport is essentially trap-free in such materials. Different blend ratios of P3HT:PDI-1 (1:1) and (1:3) show increase in the device performance with increasing PDI-1 ratio. Furthermore, thermal annealing of the devices have a significant effect in the solar cells that decreases open-circuit voltage (Voc) and fill factor FF, but increases short-circuit current (Jsc) and overall device performance. Morphological studies show that over-aggregation in traditional donor:PDI blend systems is still a big problem, which hinders charge carrier transport and performance in solar cells.

Distributed solar micro generation

Taking into account the fact that the sun’s radiation is estimated to be enough to cover 10.000 times the world’s total energy needs (BRAKMANN & ARINGHOFF, 2003), it is difficult to understand how solar photovoltaic systems (PV) are still such a small part of the energy source matrix across the globe. Though there is an ongoing debate as to whether energy consumption leads to economic growth or whether it is the other way around, the two variables appear correlated and it is clear that ensuring the availability of energy to match a country’s growth targets is one of the prime concerns for any government. The topic of centralized vs distributed electricity generation is also approached, especially in what regards the latter fit to developing countries needs, namely the lack of investment capabilities and infrastructure, scattered population, and other factors. Finally, Brazil’s case is reviewed, showing that the current cost of electricity from the grid versus the cost from PV solutions still places an investment of this nature with 9 to 16 years to reach breakeven (from a 25 year panel lifespan), which is too high compared to the required 4 years for most Brazilians. Still, recently passed legislation opened the door, even if unknowingly, to the development of co-owned solar farms, which could reduce the implementation costs by as much as 20% and hence reduce the number of years to breakeven by 3 years.

Assessing the feasibility of impregnating phase change materials in lightweight aggregate for development of thermal energy storage systems

This paper assesses the feasibility of impregnation/encasement of phase change materials (PCMs) in lightweight aggregates (LWAs). An impregnation process was adopted to carry out the encasement study of two different PCMs in four different LWAs. The leakage of the impregnated/encased PCMs was studied when they were submitted to freeze/thawing and oven drying tests, separately. The results confirmed that, the impregnation/encasement method is effective with respect to the large thermal energy storage density, and can be suitable for applications were PCMs cannot be incorporated directly such as asphalt road pavements.

Annoyance and welfare costs from the presence of renewable energy power plants: an application of the contingent valuation method

Sustainability is frequently defined by its three pillars: economically viable, socially equitable, and environmentally bearable. Consequently the evaluation of the sustainability of any decision, public or private, requires information on these three dimensions. This paper focuses on social sustainability. In the context of renewable energy sources, the examination of social sustainability requires the analysis of not only the efficiency but also the equity of its welfare impacts. The present paper proposes and applies a methodology to generate the information necessary to do a proper welfare analysis of the social sustainability of renewable energy production facilities. This information is key both for an equity and an efficiency analysis. The analysis focuses on the case of investments in renewable energy electricity production facilities, where the impacts on local residents’ welfare are often significantly different than the welfare effects on the general population. We apply the contingent valuation method to selected facilities across the different renewable energy power plants located in Portugal and conclude that local residents acknowledge differently the damage sustained by the type, location and operation of the plants. The results from these case studies attest to the need of acknowledging and quantifying the negative impacts on local communities when assessing the economic viability, social equity and environmental impact of renewable energy projects.

Monitoring energy consumption in android applications

Dissertação de Mestrado em Engenharia Informática

Spectrum-based energy leak localization

Dissertação de Mestrado em Engenharia Informática

Renewable energy system for an isolated micro grid

This paper presents the development of the power electronics needed for the interaction between the electrical generator of a wind turbine and an isolated ac micro grid. In this system there are basically two types of receptors for the energy produced by the wind turbine, which are the loads connected to the isolated micro grid and the batteries used to store energy. There are basically two states in which the system will work. One of the states is when there is enough wind power to supply the loads and the extra energy is used to charge the batteries. The other state is when there is low wind power and the batteries have to compensate the lack of power, so that the isolated micro grid has enough power to supply at least the priority loads. In this paper are presented the hardware and the control algorithm for the developed system. The topology was previously tested in computer simulations, using the software PSIM 9.0, and then validated with the implementation of a laboratory prototype.

Jet energy measurement and its systematic uncertainty in proton-proton collisions at s√=7 TeV with the ATLAS detector

The jet energy scale (JES) and its systematic uncertainty are determined for jets measured with the ATLAS detector using proton–proton collision data with a centre-of-mass energy of s√=7 TeV corresponding to an integrated luminosity of 4.7 fb −1 . Jets are reconstructed from energy deposits forming topological clusters of calorimeter cells using the anti- kt algorithm with distance parameters R=0.4 or R=0.6 , and are calibrated using MC simulations. A residual JES correction is applied to account for differences between data and MC simulations. This correction and its systematic uncertainty are estimated using a combination of in situ techniques exploiting the transverse momentum balance between a jet and a reference object such as a photon or a Z boson, for 20≤pjetT<1000 GeV and pseudorapidities |η|<4.5 . The effect of multiple proton–proton interactions is corrected for, and an uncertainty is evaluated using in situ techniques. The smallest JES uncertainty of less than 1 % is found in the central calorimeter region ( |η|<1.2 ) for jets with 55≤pjetT<500 GeV . For central jets at lower pT , the uncertainty is about 3 %. A consistent JES estimate is found using measurements of the calorimeter response of single hadrons in proton–proton collisions and test-beam data, which also provide the estimate for pjetT>1 TeV. The calibration of forward jets is derived from dijet pT balance measurements. The resulting uncertainty reaches its largest value of 6 % for low- pT jets at |η|=4.5 . Additional JES uncertainties due to specific event topologies, such as close-by jets or selections of event samples with an enhanced content of jets originating from light quarks or gluons, are also discussed. The magnitude of these uncertainties depends on the event sample used in a given physics analysis, but typically amounts to 0.5–3 %.

Studying conformally flat spacetimes with an elastic stress energy tensor using 1+3 formalism

Conformally flat spacetimes with an elastic stress energy tensor having diagonal trace-free anisotropic pressure are investigated using 1+3 formalism. The 1+3 Bianchi and Jacobi identities and Einstein field equations are written for a particular case with a conformal factor dependent on only one spatial coordinate. Solutions with non null anisotropic pressure are obtained.

Energy harvesting device based on a metallic glass/PVDF magnetoelectric laminated composite

A flexible and low cost energy harvester device based on the magnetoelectric (ME) effect has been designed using Fe64Co17Si7B12 as amorphous magnetostrictive ribbons and PVDF as the piezoelectric element. Sandwich-type laminated composite of 3 cm long has been fabricated by gluing these ribbons to the PVDF with the Devcon 5 minute epoxy. Good power output and power density of 6.4 μW and 1.5 mW/cm3, respectively, have been obtained through a multiplier circuit. All values have been measured at the magnetomechanical resonance of the laminate. The effect of the length of the ME laminate on the power output has been also studied, exhibiting a decay as the length of the ME laminate does. Nevertheless, good performance of such device has been obtained for a 0.5 cm long device, working already at 337 KHz, within the low radio frequency (LRF) range.

Metallic glass/PVDF magnetoelectric energy harvester working up to the radiofrequency range

Companies and researchers involved in developing miniaturized electronic devices face the basic problem of the needed batteries size, finite life of time and environmental pollution caused by their final deposition. The current trends to overcome this situation point towards Energy Harvesting technology. These harvesters (or scavengers) store the energy from sources present in the ambient (as wind, solar, electromagnetic, etc) and are costless for us. Piezoelectric devices are the ones that show a higher power density, and materials as ceramic PZT or polymeric PVDF have already demonstrated their ability to act as such energy harvester elements. Combinations between piezoelectric and electromagnetic mechanism have been also extensively investigated. Nevertheless, the power generated by these combinations is limited under the application of small magnetic fields, reducing the performance of the energy harvester [1]. In the last years the appearance of magnetoelectric (ME) devices, in which the piezoelectric deformation is driven by the magnetostrictive element, enables to extract the energy of very small electromagnetic signals through the generated magnetoelectric voltage at the piezoelectric element. However, very little work has been done testing PVDF polymer as piezoelectric constituent of the ME energy harvester device, and only to be proposed as a possibility of application [2]. Among the advantages of using piezopolymers for vibrational energy harvesting we can remember that they are ductile, resilient to shock, deformable and lightweight. In this work we demonstrate the feasibility of using magnetostrictive Fe-rich magnetic amorphous alloys/piezoelectric PVDF sandwich-type laminated ME devices as energy harvesters. A very simple experimental set-up will show how these laminates can extract energy, in amounts of μW, from an external AC field.