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Wednesday, May 11, 2011

Pigment-Free Feathers Inspire Mirrorless Laser (photonics.com | May 2011 | Research & Technology)

Pigment-Free Feathers Inspire Mirrorless Laser (photonics.com | May 2011 | Research & Technology)

Synth-ethic: Art and Synthetic Biology Exhibition — Vienna, Austria

Synth-ethic: Art and Synthetic Biology Exhibition — Vienna, Austria

Bacterial Radio exhibits several bacterially-grown platinum/germanium electrical circuits (crystal radios) on glass substrates. Joe Davis, in collaboration with Ido Bachelet and Tara Gianoulis from Harvard Medical School in Boston, used bacteria altered with variants of a gene from orange marine puffball sponges (Tethya aurantia) to plate electronic circuits on Petri dishes and microscope slides. This gene codes for a protein – silicatein – that normally forms Tethya aurantia’s glass skeleton, its tiny, glass, needle-like spicules composed of silicon and oxygen. Variants of this gene have now been optimized to plate metallic conductors and semiconductors including germanium, titanium dioxide, platinum and other materials. Here, genetically-modified bacteria are embedded in non-conductive materials containing metal salts, and then optically induced to plate specific, electrically conductive circuits. These Bacterial Radios on display are connected to high impedance telephone headsets, antennae and ground, so that visitors may use them to actually listen to AM radio broadcasts.

▶ Racecar by Suzanna Choffel

▶ Racecar by Suzanna Choffel

Monday, May 2, 2011

flexatone h.f.p. | Christopher Ariza | athenaCL

flexatone h.f.p. | Christopher Ariza | athenaCL

The athenaCL system is an open-source, object-oriented composition tool written in Python. The system can be scripted and embedded, and includes integrated instrument libraries, post-tonal and microtonal pitch modeling tools, multiple-format graphical outputs, and musical output in Csound, SuperCollider, Pure Data, MIDI, audio file, XML, and text formats.

Musical parts are deployed as Textures, layered surface-defining objects containing numerous independent ParameterObjects to control pitch, tempo, rhythm, amplitude, panning, and instrument (Csound) parameters. The system includes an integrated library of Csound and SuperCollider instruments, and supports output for external Csound instruments, MIDI, and a variety of alternative formats. Over eighty specialized Generator, Rhythm, and Filter ParameterObjects provide tools for stochastic, chaotic, cellular automata based, Markov based, generative grammar and Lindenmayer system (L-system), wave-form, fractional noise (1/f), genetic, Xenakis sieve, linear and exponential break-point segments, masks, and various other algorithmic models. ParameterObjects can be embedded in other ParameterObjects to provide powerful dynamic and masked value generation. Textures can be combined and edited, and tuned with algorithmic Temperament objects. Texture Clones allow the filtering and processing of Texture events, performing transformations not possible with parameter generation alone.

The algorithmic system uses Path objects to organize and share pitch groups. Paths provide simultaneous representations of ordered content groups in set-class, pitch-class space, and pitch space.

Sunday, May 1, 2011

New ORNL solar cell technology cranks up efficiency | Science Blog

New ORNL solar cell technology cranks up efficiency | Science Blog

The new solar structure consists of n-type nanocones surrounded by a p-type semiconductor. The n-type nanoncones are made of zinc oxide and serve as the junction framework and the electron conductor. The p-type matrix is made of polycrystalline cadmium telluride and serves as the primary photon absorber medium and hole conductor.

With this approach at the laboratory scale, Xu and colleagues were able to obtain a light-to-power conversion efficiency of 3.2 percent compared to 1.8 percent efficiency of conventional planar structure of the same materials.

“We designed the three-dimensional structure to provide an intrinsic electric field distribution that promotes efficient charge transport and high efficiency in converting energy from sunlight into electricity,” Xu said.

Key features of the solar material include its unique electric field distribution that achieves efficient charge transport; the synthesis of nanocones using inexpensive proprietary methods; and the minimization of defects and voids in semiconductors. The latter provides enhanced electric and optical properties for conversion of solar photons to electricity.

Because of efficient charge transport, the new solar cell can tolerate defective materials and reduce cost in fabricating next-generation solar cells.

“The important concept behind our invention is that the nanocone shape generates a high electric field in the vicinity of the tip junction, effectively separating, injecting and collecting minority carriers, resulting in a higher efficiency than that of a conventional planar cell made with the same materials,” Xu said.

Research that forms the foundation of this technology was accepted by this year’s Institute of Electrical and Electronics Engineers photovoltaic specialist conference and will be published in the IEEE Proceedings. The papers are titled “Efficient Charge Transport in Nanocone Tip-Film Solar Cells” and “Nanojunction solar cells based on polycrystalline CdTe films grown on ZnO nanocones.”