28 documents found, page 1 of 3
The effect of broadleaf forests in wildfire mitigation in the WUI – A simulatio...
Oliveira, A.S.; Silva, J.S.; Guiomar, N.; Fernandes, P.; Nereu, M.; Gaspar, J.; Lopes, R.F.R.; Rodrigues, J.P.C.The increasing occurrence of large wildfires in Southern European countries calls for the adoption of more effective measures of fire prevention, to protect people and infrastructures, namely in the Wildland-Urban Interface (WUI). Previous research suggests that broadleaf forests could mitigate the effects of these wildfires due to their lower flammability. However, few attempts have been made to investigate th...
A software defined radio based anti-UAV mobile system with jamming and spoofing...
Branco Ferreira, R.; Gaspar, J.; Sebastião, P.; Souto, N.The number of incidents between unmanned aerial vehicles (UAVs) and aircrafts at airports and airfields has been increasing over the last years. To address the problem, in this paper we describe a portable system capable of protecting areas against unauthorized UAVs, which is based on the use of low-cost SDR (software defined radio) platforms. The proposed anti-UAV system supports target localization and integr...
O poder da nanofabricação: substratos de alta performance para células solares ...
Teixeira, J.T.; Lopes, T.S.; Oliveira, K.; Curado, M.A.; Cunha, J.M.V.; Ribeiro, R.M.; Oliveira, A.J.N.; Barbosa, J.R.S.; Violas, A.; Rocha, C.RESUMO: O grupo de Nanofabrication for Optoelectronic Applications -NOA- inserido no International Iberian Nanotechnology Laboratory (INL) tem focado grande parte da sua investigação e operações no desenvolvimento de substratos de alta performance, baseados em diferentes esquemas de manipulação da luz para aplicação em células solares de Cu(In,Ga)Se2 (CIGS). Estes substratos baseiam-se na inserção de uma camada...
Capture of UAVs through GPS spoofing using low-cost SDR platforms
Gaspar, J.; Ferreira, R.; Sebastião, P.; Souto, N.The increased use of unmanned aerial vehicles (UAVs), better known as drones, by civilians has grown exponentially and their autonomous flight control systems have improved significantly, which has resulted in a greater number of accidents and dangerous situations. To help resolve this problem, in this paper, we address the use of low-cost Software Defined Radio (SDR) platforms for simulating a global navigatio...
Effective GPS jamming techniques for UAVs using low-cost SDR platforms
Ferreira, R.; Gaspar, J.; Sebastião, P.; Souto, N.Lately, a rising number of incidents between unmanned aerial vehicles (UAVs) and airplanes have been reported in airports and airfields. In order to help cope with the problem of unauthorized UAV operations, in this paper we evaluate the use of low cost SDR platforms (software defined radio) for the implementation of a jammer able to generate an effective interfering signal aimed at the GPS navigation system. U...
Field-effect transistors made of graphene grown on recycled copper foils
Machado, G.; Cerqueira, M. F.; Borme, J.; Martins, M.; Gaspar, J.; Alpuim, P.In this paper, recycled low purity copper foils (98%) are tested after a multiple-use process for obtaining singlelayer graphene (SLG). The graphene transfer technique based on water electrolysis (bubbling) is used for the preservation of the Cu foils in multiple graphene deposition cycles. Preliminary cleaning by O2 plasma remove carbon residues from the copper surface. The Cu foils are then cleaned with hydro...
O poder da nanofabricação: substratos de alta performance para células solares ...
Teixeira, J.T.; Lopes, T.S.; Oliveira, K.; Curado, M.A.; Cunha, J.M.V.; Ribeiro, R.M.; Oliveira, A.J.N.; Barbosa, J.R.S.; Violas, A.; Rocha, C.RESUMO: O grupo de Nanofabrication for Optoelectronic Applications -NOA- inserido no International Iberian Nanotechnology Laboratory (INL) tem focado grande parte da sua investigação e operações no desenvolvimento de substratos de alta performance, baseados em diferentes esquemas de manipulação da luz para aplicação em células solares de Cu(In,Ga)Se2 (CIGS). Estes substratos baseiam-se na inserção de uma camada...
A morphological and electronic study of ultrathin rear passivated Cu(In,Ga)Se2 ...
Bose, S.; Cunha, J.M.V.; Borme, J.; Chen, W.C.; Nilsson, N.S.; Teixeira, J.P.; Gaspar, J.; Leitão, J.P.; Edoff, M.; Fernandes, P. A.; Salomé, P.M.P.The effects of introducing a passivation layer at the rear of ultrathin Copper Indium Gallium di-Selenide Cu(In,Ga)Se2 (CIGS) solar cells is studied. Point contact structures have been created on 25 nm Al2O3 layer using e-beam lithography. Reference solar cells with ultrathin CIGS layers provide devices with average values of light to power conversion efficiency of 8.1% while for passivated cells values reached...
A morphological and electronic study of ultrathin rear passivated Cu(In,Ga)Se2 ...
Bose, S.; Cunha, J. M. V.; Borme, J.; Chen, W. C.; Nilsson, N. S.; Teixeira, J. P.; Gaspar, J.; Leitão, J. P.; Edoff, M.; Fernandes, P. A.The effects of introducing a passivation layer at the rear of ultrathin Copper Indium Gallium di-Selenide Cu(In,Ga)Se2 (CIGS) solar cells is studied. Point contact structures have been created on 25 nm Al2O3 layer using e-beam lithography. Reference solar cells with ultrathin CIGS layers provide devices with average values of light to power conversion efficiency of 8.1 % while for passivated cells values reache...
Insulator materials for interface passivation of Cu(In,Ga)Se2 thin films
Cunha, J. M. V.; Fernandes, P. A.; Hultqvist, A.; Teixeira, J. P.; Bose, S.; Vermang, B.; Garud, S.; Buldu, D.; Gaspar, J.; Edoff, M.; Leitão, J. P.In this work, Metal-Insulator-Semiconductor (MIS) structures were fabricated in order to study different types of insulators, namely, aluminum oxide (Al2O3), silicon nitride (Si3Nx) and silicon oxide (SiOx) to be used as passivation layers in Cu(In,Ga)Se2 (CIGS) thin film solar cells. The investigated stacks consisted of SLG/Mo/CIGS/insulator/Al. Raman scattering and Photoluminescence measurements were done to ...