Warning to navigators: IPCC report on climate change mitigation

6 p.Despite the proliferation of climate change plans and strategies, global emissions have accelerated over the last decade. *If the present trends continue, temperatures will have risen between 3.7 and 4.3ºC by the end of the century. *To stabilise temperatures at 2ºC, emissions must be reduced between 40 and 70% by 2050 and have dropped to almost zero in 2100. This will imply a radical change at technological and institutional level; it will also mean an important transformation in lifestyles. *Fortunately, there are several stabilising options which are technically viable and economically assumable. *Nevertheless, it is important that investments are materialised in the coming decades (2010-2030) to avoid having to use technologies to capture emissions in the atmosphere (negative emissions) that would entail higher costs and greater risks. *International cooperation and the search for fair agreements are essential for making progress with and maintaining mitigation efforts

Quarterly Technical Progress Report for the Period Ending 30 September 2002 (Quarterly Report #8)

Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 July to 30 September 2002 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on feasibility demonstration of direct feeding of coal combustion gas to microalgae. Aquasearch continued their effort on selection and characterization of microalgae suitable for CO{sub 2} sequestration. University of Hawaii continued effort on system optimization of the CO{sub 2} sequestration system

Begiak erne: klima aldaketa arintzeari buruzko IPCC-ren txostena

6 p.Despite the proliferation of climate change plans and strategies, global emissions have accelerated over the last decade. *If the present trends continue, temperatures will have risen between 3.7 and 4.3ºC by the end of the century. *To stabilise temperatures at 2ºC, emissions must be reduced between 40 and 70% by 2050 and have dropped to almost zero in 2100. This will imply a radical change at technological and institutional level; it will also mean an important transformation in lifestyles. *Fortunately, there are several stabilising options which are technically viable and economically assumable. *Nevertheless, it is important that investments are materialised in the coming decades (2010-2030) to avoid having to use technologies to capture emissions in the atmosphere (negative emissions) that would entail higher costs and greater risks. *International cooperation and the search for fair agreements are essential for making progress with and maintaining mitigation efforts

Study of the processing conditions for stainless steel additive manufacturing using femtosecond laser

The use of ultrashort-pulsed (USP) lasers in Additive Manufacturing (AM) enables the processing of different materials and has the potential to reduce the sizes and shapes manufactured with this technology. This work confirms that USP lasers are a viable alternative for Laser Powder Bed Fusion (LPBF) when higher precision is required to manufacture certain critical parts. Promising results were obtained using tailored and own-produced stainless steel powder particles, manufacturing consistent square layers with a series of optimized processing parameters. The critical role of processing parameters is confirmed when using this type of lasers, as a slight deviation of any of them results in an absence of melting. For the first time, melting has been achieved at low pulse repetition (500 kHz) and using low average laser power values (0.5–1 W), by generating heat accumulation at reduced scanning speeds. This opens up the possibility of further reducing the minimum size of parts when using USP lasers for AM

N-(Diazoacetyl)oxazolidin-2-thiones as Sulfur Donor Reagents: Asymmetric Synthesis of Thiiranes from Aldehydes

Financial support was provided by the University of the Basque Country UPV/EHU (UFI 11/22), Basque Government (GV grant No IT-291-07), and Ministerio de Ciencia e Innovación (MICINN, Grant CTQ2007-68095-C02), Spain. A. L. thanks MICINN and European Social Foundation for a Ramón y Cajal contract. I. O. thanks MCINN for a fellowship. We also thank SGIker (UPV/EHU) for providing NMR, HRMS, X-Ray, and computational resources

Direct patterning of periodic semiconductor nanostructures using single-pulse nanosecond laser interference

We demonstrate an effective method for fabricating large area periodic two-dimensional semiconductor nanostructures by means of single-pulse laser interference. Utilizing a pulsed nanosecond laser with a wavelength of 355 nm, precisely ordered square arrays of nanoholes with a periodicity of 300 nm were successfully obtained on UV photoresist and also directly via a resist-free process onto semiconductor wafers. We show improved uniformity using a beam-shaping system consisting of cylindrical lenses with which we can demonstrate highly regular arrays over hundreds of square micrometers. We propose that our novel observation of direct pattern transfer to GaAs is due to local congruent evaporation and subsequent droplet etching of the surface. The results show that single-pulse interference can provide a rapid and highly efficient route for the realization of wide-area periodic nanostructures on semiconductors and potentially on other engineering materials

Polarization conversion on nanostructured metallic surfaces fabricated by LIPSS

Conference on Laser-Based Micro-and Nanoprocessing (LBMP) at Photonics West Conference (13ª. 2019. San Francisco, California). ISBN: 978-1-5106-2455-9 © 2019 SPIE. This work is part of the following projects: ECOGRAB, funded by the Government of Spain under the RETOS COLABORACIÓN I+D+i programme. LASER4SURF has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 768636.Waveplates modify polarization by generating a phase change. Laser Induced Periodic Surface Structures (LIPSS) have recently started to be studied as waveplates due to the birefringence in-duced by the nanoripples, easily fabricated in a one-step process by laser, where LIPSS morphology is defined by the characteristics of the laser process parameters and the substrate material. The optical properties of these waveplates are defined by LIPSS parameters such as period, depth or width of the ripples. In this work we have deposited thin film coatings on stainless steel samples containing LIPSS for different coating thickness and composition. Results show that thin film coatings are a good candidate for the tunability of LIPSS birefringence since the coating modifies the induced polarization change and reflectivity of the sample depending on coating thickness and composition, as expected from numerical simulations.Depto. de ÓpticaFac. de Ciencias FísicasTRUEUnión Europea. H2020Ministerio de Ciencia e Innovación (MICINN)pu

LIPSS manufacturing with regularity control through laser wavefront curvature

Laser-Induced Periodic Surface Structures (LIPSS) manufacturing is a convenient laser direct-writing technique for the fabrication of nanostructures with adaptable characteristics on the surface of virtually any material. In this paper, we study the influence of 1D laser wavefront curvature on nanoripples spatial regularity, by irradiating stainless steel with a line-focused ultrafast laser beam emitting 120 fs pulses at a wavelength of 800 nm and with 1 kHz repetition rate. We find high correlation between the spatial regularity of the fabricated nanostructures and the wavefront characteristics of the laser beam, with higher regularity being found with quasi-plane-wave illumination. Our results provide insight regarding the control of LIPSS regularity, which is essential for industrial applications involving the LIPSS generation technique

Polarization conversion on nanostructured metallic surfaces fabricated by LIPSS

Waveplates modify polarization by generating a phase change. Laser Induced Periodic Surface Structures (LIPSS) have recently started to be studied as waveplates due to the birefringence in-duced by the nanoripples, easily fabricated in a one-step process by laser, where LIPSS morphology is defined by the characteristics of the laser process parameters and the substrate material. The optical properties of these waveplates are defined by LIPSS parameters such as period, depth or width of the ripples. In this work we have deposited thin film coatings on stainless steel samples containing LIPSS for different coating thickness and composition. Results show that thin film coatings are a good candidate for the tunability of LIPSS birefringence since the coating modifies the induced polarization change and reflectivity of the sample depending on coating thickness and composition, as expected from numerical simulations

New climate scenario framework implementation in the GCAM integrated assessment model

48 p.This report has various objectives: (i) to provide an overview of the climate Integrated Assessment approach; (ii) to describe the Global Climate Assessment Model (GCAM); (iii) to outline the new IPCC scenario framework represented by the Shared Socio-economic Pathways (SSPs) and the Representative Concentration Pathways (RCPs); and (iv) to document the implementation of the new scenario framework in version 3.1 of the GCAM. The GCAM baseline is thus calibrated to the “Middle of the Road” or SSP2 scenario using the data calculated by the OECD. The implications of this scenario are important because it will probably become a standard scenario among the research community. The exogenous variables, the implications for income convergence and the results in terms of energy mix, emissions, temperature and radiative forcing of SSP2 implementation in the GCAM are presented at both global and regional levels. These results are also compared with the GCAM-Reference baseline and the IPCC SRES representative scenarios. Then the feasibility, cost and implications of a climate policy that seeks to stabilize temperature at 2ºC (2.6 W/m2 RCP) using a global uniform carbon tax are analyzed. The study is completed by a decomposition analysis that enables the main driving factors of CO2 variation to be identified, including population, affluence, energy intensity, carbon intensity and fossil-fuel share of the energy mix. Finally we draw some conclusions and highlight points for further research