Approximating Mexican highways with slime mould

Plasmodium of Physarum polycephalum is a single cell visible by unaided eye. During its foraging behavior the cell spans spatially distributed sources of nutrients with a protoplasmic network. Geometrical structure of the protoplasmic networks allows the plasmodium to optimize transport of nutrients between remote parts of its body. Assuming major Mexican cities are sources of nutrients how much structure of Physarum protoplasmic network correspond to structure of Mexican Federal highway network? To find an answer undertook a series of laboratory experiments with living Physarum polycephalum. We represent geographical locations of major cities by oat flakes, place a piece of plasmodium in Mexico city area, record the plasmodium's foraging behavior and extract topology of nutrient transport networks. Results of our experiments show that the protoplasmic network formed by Physarum is isomorphic, subject to limitations imposed, to a network of principle highways. Ideas and results of the paper may contribute towards future developments in bio-inspired road planning

Quinine doped hybrid sol-gel coatings for wave guiding and optical applications

Pure and quinine doped silica coatings have been prepared over sodalime glasses. The coatings were consolidated at low temperature (range 60-180 A degrees C) preserving optical activity of quinine molecule. We designed a device to test the guiding properties of the coatings. We confirmed with this device that light injected in pure silica coatings is guided over distances of meters while quinine presence induces isotropic photoluminescence. With the combined use of both type of coatings, it is possible to design light guiding devices and illuminate regions in glass elements without electronic circuits

About some properties of amorphous gadolinium-iron thin films

Des films minces amorphes d'alliages de gadolinium et de fer de compositions très variables sont préparés par évaporation sous vide. Sur des échantillons bien caractérisés (structure, composition, épaisseur, homogénéité), des mesures de spectres d'énergie ont permis de déterminer le spectre des excitations électroniques entre 5 et 150 eV et des observations en microscopie de Lorentz d'étudier la distribution locale de l'aimantation.Amorphous thin foils of Fe-Gd alloys with very different compositions are prepared by vacuum evaporation. On well characterized specimens (structure, concentration, thickness, homogeneity), energy loss measurements have led to the determination of the electron excitation spectrum between 5 and 150 eV and Lorentz microscopy observations have been used to visualize the local magnetization distribution

Adsorption of chlorinated compounds (chLorobenzene, chLoroform, and carbon tetrachloride) on microporous SiO2, Ag-doped SiO2 and natural and dealuminated clinoptilolites

Adsorption isotherms of chLoroorganic compounds on natural and dealuminated clinoptilolite zeolites, as well as on pure and Ag-doped microporous SiO2, were measured by a gas chromatography technique. The SiO2 microporous solids were synthesized by the sol-gel method from tetraethoxysilane and in the presence of methanol. Dealuminated clinoptilolite zeolites were obtained by means of HCl treatment of a natural precursor. Adsorption of chlorinated compounds (CxHyClz), such as chLorobenzene, chLoroform, and carbon tetrachloride, on SiO2, Ag-doped SiO2 and on the clinoptilolite zeolites was studied in the temperature range of 398-498 K. The Freundlich and Dubinin-Astakhov adsorption equations approximately fitted the CxHyClz adsorption data, within the selected temperature range. The energies of interaction between chlorinated adsorbates and microporous SiO2, Ag-doped SiO2, and clinoptilolite substrates were evaluated from the isosteric heats of adsorption (q(st)), which were found to obey the following decreasing order: q(st) (chLorobenzene) > q(st) (chLoroform) > q(st) (carbon tetrachloride)

Gain-Controlled Erbium-Doped Fiber Amplifier Using Mode-Selective Photonic Lantern

For the first time, we demonstrate the implementation of a core pumped few mode erbium amplifier utilizing a mode selective photonic lantern for spatial modal control of the pump light. This device is able to individually amplify the first six fiber modes with low differential modal gain. In addition, we obtained differential modal gain lower than 1 dB and signal gain of approximately 16.17 dB at λs = 1550 nm through forward pumping the LP21 modes at λp = 976 nm

Few-Mode Erbium-Doped Fiber Amplifier With Photonic Lantern For Pump Spatial Mode Control

We demonstrate a few-mode erbium-doped fiber amplifier employing a mode-selective photonic lantern for controlling the modal content of the pump light. Amplification of six spatial modes in a 5 m long erbium-doped fiber to ∼6.2 dBm average power is obtained while maintaining high modal fidelity. Through mode-selective forward pumping of the two degenerate LP21 modes operating at 976 nm, differential modal gains of \u3c1 dB between all modes and signal gains of ∼16 dB at 1550 nm are achieved. In addition, low differential modal gain for near-full C-band operation is demonstrated

Six Mode Erbium-Doped Fiber Amplifier Using Mode Selective Photonic Lantern

We demonstrate a six-mode erbium doped fiber amplifier incorporating a photonic lantern for modal gain control. Signal gain \u3c 20 dB and differential modal gain \u3e3 dB were obtained through mode selective pumping using LP21 mode. © 2015 OSA