Energy end-use technologies for the 21st century

The World Energy Council’s recent study examined the potential of energy end-use technologies and of research, development, and demonstration (RD&D) into these technologies on a global scale. Surprises are likely, but nevertheless, current research and development offer a picture of what might happen in the future as new technologies face the competition of the marketplace. Given the breadth of energy end-use technologies and the differences between regions and economic conditions, the study focused on technologies that appear most important from today’s vantage point. Globally, robust research and development followed by demonstrations of new end-use technologies can potentially save at least 110 EJ/year by 2020 and over 300 EJ/year by 2050. If achieved, this translates to worldwide energy savings of as much as 25% by 2020 and over 40% by 2050, over what may be required without these technologies. It is almost certain that no single technology, or even a small set of technologies, will dominate in meeting the needs of the globe in any foreseeable timeframe. Absent a significant joint government–industry effort on end-use technology RD&D, the technologies needed will not be ready for the marketplace in the timeframes required with even the most pessimistic scenarios. Based on previous detailed analyses for the United States, an international expenditure of $4 billion per year seems more than justified. The success of new energy end-use technologies depends on new RD&D investments and policy decisions made today. Governments, in close cooperation with industry, must carefully consider RD&D incentives that can help get technologies from the laboratory or test-bed to market. Any short-term impact areas are likely to benefit from focused RD&D. These include electricity transmission and distribution, distributed electricity production, transportation, the production of paper and pulp, iron and steel, aluminum, cement and chemicals, and information and communication technologies. For long-term impact, significant areas include fuel cells, hydrogen fuel, and integrated multi-task energy systems

Characterization of 1D photonic crystal nanobeam cavities using curved microfiber

We investigate high-Q, small mode volume photonic crystal nanobeam cavities using a curved, tapered optical microfiber loop. The strength of the coupling between the cavity and the microfiber loop is shown to depend on the contact position on the nanobeam, angle between the nanobeam and the microfiber, and polarization of the light in the fiber. The results are compared to a resonant scattering measurement

Energy End-Use Technologies for the 21st Century. A Report of the World Energy Council

This report makes clear the opportunities and places technology development firmly centre stage in meeting and overcoming the challenges confronting the energy industry and policy makers. Energy End-Use Technologies for the 21st Century makes it crystal clear that technologies deployed in 20 to 50 years will be the result of policy and funding decisions taken now and that we cannot afford to duck these decisions if we are to meet the World Energy Council’s goals of energy availability, accessibility and acceptability

Integrated optical addressing of a trapped ytterbium ion

We report on the characterization of heating rates and photo-induced electric charging on a microfabricated surface ion trap with integrated waveguides. Microfabricated surface ion traps have received considerable attention as a quantum information platform due to their scalability and manufacturability. Here we characterize the delivery of 435 nm light through waveguides and diffractive couplers to a single ytterbium ion in a compact trap. We measure an axial heating rate at room temperature of $0.78\pm0.05$ q/ms and see no increase due to the presence of the waveguide. Furthermore, the electric field due to charging of the exposed dielectric outcoupler settles under normal operation after an initial shift. The frequency instability after settling is measured to be 0.9 kHz.Comment: 7 pages, 8 figure

Hybrid-learning for social design

Underlying causes of conflict, inequity, and injustice remain deeply entrenched in the lives of people ranging from impoverished villages to overpopulated megalopolises. To help address these complex issues, social design brings together designers from varying disciplines to address the needs of the community. While universities across the world recognize the need to introduce social design pedagogy into their curriculum, many programs remain confined within Western post-graduate education. In response, two multidisciplinary professors initiated a team-taught \u27Design for Social Change\u27 course in an undergraduate design program in Dubai, UAE. Open to students across disciplines, the course followed a hybrid-learning approach to planning, conducting, and evaluating learning activities. The methodology empowered students to determine their project interest, cooperatively build research, and value their diverse skills. This paper introduces the notion of hybrid-learning, collabor-active team-teaching in an interdisciplinary classroom, and applies the methodology to a social design course in the MENA region. This paper has been presented as part of the Tasmeem Exploration Platform during Tasmeem Conference, Doha, 2013

Effect of atomic layer deposition on the quality factor of silicon nanobeam cavities

In this work we study the effect of thin-film deposition on the quality factor (Q) of silicon nanobeam cavities. We observe an average increase in the Q of 38±31% in one sample and investigate the dependence of this increase on the initial nanobeam hole sizes. We note that this process can be used to modify cavities that have larger than optimal hole sizes following fabrication. Additionally, the technique allows the tuning of the cavity mode wavelength and the incorporation of new materials, without significantly degrading Q

Geospatial analysis and living urban geometry

This essay outlines how to incorporate morphological rules within the exigencies of our technological age. We propose using the current evolution of GIS (Geographical Information Systems) technologies beyond their original representational domain, towards predictive and dynamic spatial models that help in constructing the new discipline of "urban seeding". We condemn the high-rise tower block as an unsuitable typology for a living city, and propose to re-establish human-scale urban fabric that resembles the traditional city. Pedestrian presence, density, and movement all reveal that open space between modernist buildings is not urban at all, but neither is the open space found in today's sprawling suburbs. True urban space contains and encourages pedestrian interactions, and has to be designed and built according to specific rules. The opposition between traditional self-organized versus modernist planned cities challenges the very core of the urban planning discipline. Planning has to be re-framed from being a tool creating a fixed future to become a visionary adaptive tool of dynamic states in evolution

Optically coupled cavities for wavelength switching

An optical bistable device which presents hysteresis behavior is proposed and experimentally demonstrated. The system finds applications in wavelength switching, pulse reshaping and optical bistability. It is based on two optically coupled cavities named master and slave. Each cavity includes a semiconductor optical amplifier (SOA), acting as the gain medium of the laser, and two pair of fiber Bragg gratings (FBG) which define the lasing wavelength (being different in each cavity). Finally, a variable optical coupler (VOC) is employed to couple both cavities. Experimental characterization of the system performance is made analyzing the effects of the coupling coefficient between the two cavities and the driving current in each SOA. The properties of the hysteretic bistable curve and switching can be controlled by adjusting these parameters and the loss in the cavities. By selecting the output wavelength (λ1 or λ2) with an external filter it is possible to choose either the invert or non-invert switched signal. Experiments were developed employing both optical discrete components and a photonic integrated circuit. They show that for 8 m-long cavities the maximum switching frequency is about 500 KHz, and for 4 m-long cavities a minimum rise-time about 21 ns was measured. The switching time can be reduced by shortening the cavity lengths and using photonic integrated circuits.Centro de Investigaciones Óptica