A study by high energy transfer inelastic neutron scattering spectroscopy of the mineral fraction of ox femur bone

We have used high energy transfer (HET) inelastic neutron scattering spectroscopy to measure the vibrational modes in the spectra of hydroxyapatite, bone and brushite to confirm our earlier work that only a fraction of the hydroxyl groups in bone mineral are substituted. The HET spectra are better observed due to the higher scattering cross section of hydrogen compared with the other elements in the calcium phosphate compounds. (C) 2003 Elsevier Science B.V. All rights reserved.

Photochromic switches incorporated in bridging ligands: a new tool to modulate energy-transfer processes

The thoughtful construction of molecular switches has led to a gamut of supramolecular systems that can be used in molecular electronics. These include molecules based on thienylethenes, spiropyrans, fulgides, dithienylphenanthrolines, and diazafluorenes. This article reviews the recent developments made in the synthesis and characterization of all these systems, thereby allowing a comparative study to validate the viability of these switchable molecules on a nanoscale. Also, the drawbacks of each class are demonstrated and, at the same time, the remedies for further improvisation are prescribed. We have made an honest attempt to present at? exhaustive account of all the different photochromic switches developed by us hitherto.

Electronic energy transfer in a dinuclear Ru/Os complex containing a photoresponsive dithienylethene derivative as bridging ligand

In order to build up a multicomponent system able to perform useful light-induced functions, a dithienylethene-bridged heterodinuclear metal complex (Ru/Os) has been prepared. The compound was characterized and its photophysical properties studied in detail.

Fast northward energy transfer in the Atlantic due to Agulhas rings

The adiabatic transit time of wave energy radiated by an Agulhas ring released in the South Atlantic Ocean to the North Atlantic Ocean is investigated in a two-layer ocean model. Of particular interest is the arrival time of baroclinic energy in the northern part of the Atlantic, because it is related to variations in the meridional overturning circulation. The influence of the Mid-Atlantic Ridge is also studied, because it allows for the conversion from barotropic to baroclinic wave energy and the generation of topographic waves. Barotropic energy from the ring is present in the northern part of the model basin within 10 days. From that time, the barotropic energy keeps rising to attain a maximum 500 days after initiation. This is independent of the presence or absence of a ridge in the model basin. Without a ridge in the model, the travel time of the baroclinic signal is 1300 days. This time is similar to the transit time of the ring from the eastern to the western coast of the model basin. In the presence of the ridge, the baroclinic signal arrives in the northern part of the model basin after approximately 10 days, which is the same time scale as that of the barotropic signal. It is apparent that the ridge can facilitate the energy conversion from barotropic to baroclinic waves and the slow baroclinic adjustment can be bypassed. The meridional overturning circulation, parameterized in two ways as either a purely barotropic or a purely baroclinic phenomenon, also responds after 1300 days. The ring temporarily increases the overturning strength. Th presence of the ridge does not alter the time scales.

A PRELIMINARY ANALYSIS OF THE ENERGY TRANSFER BETWEEN THE DARK SECTORS OF THE UNIVERSE

We study the mutual interaction between the dark sectors (dark matter and dark energy) of the Universe by resorting to the extended thermodynamics of irreversible processes and constrain the former with supernova type Ia data. As a by-product, the present dark matter temperature results are not extremely small and can meet the independent estimate of the temperature of the gas of sterile neutrinos.

Energy Transfer in Nanostructured Films Containing Poly(p-phenylene vinylene) and Acceptor Species

The combination of luminescent polymers and suitable energy-accepting materials may lead to a molecular-level control of luminescence in nanostructured films. In this study, the properties of layer-by-layer (LbL) films of polyp-phenylene vinylene) (PPV) were investigated with steady-state and time-resolved fluorescence spectroscopies, where fluorescence quenching was controlled by interposing inert polyelectrolyte layers between the PPV donor and acceptor layers made with either Congo Red (CR) or nickel tetrasulfonated phthalocyanine (NiTsPc). The dynamics of the excited state of PPV was affected by the energy-accepting layers, thus confirming the presence of resonant energy transfer mechanisms. Owing to the layered structured of both energy donor and acceptor units, energy transfer varied with the distance between layers, r, according to 1/r(n) with n = 2 or 3, rather than with 1/r(6) predicted by the Forster theory for interacting point dipoles.

On the energy transfer from a polymer host to the rhenium(I) complex in OLEDs

Photoluminescence and electroluminescence of PVK films doped with fac-[ClRe(CO)(3)(bpy)], bpy=2,2`-bipyridine, are investigated. Photoluminescence spectra of spin-coated PVK films (lambda(exc)=290 nm) exhibit a broad band centered at 405 nm. As the concentration of dopant increases, the polymer emission is quenched and a band at 555 nm appears (isosbestic point at 475 nm). In OLEDs with ITO/PEDOT:PSS/PVK/butylPBD/Al architecture doped with fac-[ClRe(CO)(3)(bpy)], the polymer host emission is completely quenched even at the lowest concentration of dopant. The electroluminescence spectra of the devices show that there is an efficient energy transfer from the host to the dopant, which exhibits a very intense emission at 580 nm. (C) 2009 Elsevier B.V. All rights reserved.

Efficient and low cost devices for solar energy conversion: Efficiency and stability of some natural-dye-sensitized solar cells

Dye-sensitized solar cells, named by us Dye-Cells, are one of the most promising devices for solar energy conversion due to their reduced production cost and low environmental impact, especially those sensitized by natural dyes. The efficiency and stability of devices based on natural sensitizers such as mulberry (Morus alba Lam), blueberry (Vaccinium myrtillus Lam), and jaboticaba`s skin (Mirtus cauliflora Mart) were investigated. Dye-Cells prepared with aqueous mulberry extract presented the highest P(max) value (1.6 mW cm(-2)) with J(sc) = 6.14 mA cm(-2) and V(oc) = 0.49 V, Photoelectrochemical parameters of 16 cm(2) active area devices sensitized by mulberry dye were constant for 14 weeks of continuous evaluation. Moreover, the cell remained stable even after 36 weeks with a fairly good efficiency. Therefore, mulberry dye opens up a perspective of commercial feasibility for inexpensive and environmentally friendly Dye-Cells. (C) 2009 Elsevier B.V. All rights reserved.

Prediction of Soil Properties from the Concepts of Energy Transfer in Dynamic Penetration Tests

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Embryo Transfer Efficiency of Quarter Horse Athletic Mares

This study was designed to compare embryo recovery rates and pregnancy rates of athletic and breeding Quarter Horse mares in a tropical warm climate. Thirty-nine barrel racing mares in training and 135 breeding mares as control donors were included. During the training period, the ambient temperature ranged from 31 degrees C to 36 degrees C and the average humidity from 70% to 90%. After the detection of a 35-mm follicle by ultrasound, ovulation was induced with 1 mg of deslorelin acetate (i.m), and insemination was performed 24 hours later with cooled and fresh semen from different fertile stallions. Embryos were collected on day 8 postovulation. The body temperature (rectal) was evaluated from eight athletic donor mares randomly selected from the same studied group. A total of 138 and 657 embryo collections were carried out on training and breeding mares, respectively, with a total of 105 (76%) and 466 (71%) embryos collected (P > .05). Similarly, no differences (P > .05) were observed for the pregnancy rates on day 15 (82/105, 78% vs. 370/466,79%), and day 40 (73/105, 69% vs. 328/466,70%) between the training and breeding donor mares. Just after training, the body temperature increased to an average of 39.4 degrees C and the respiratory rate from 14.5 to 35.3 breaths per minute. The results of the present study showed that embryo production from appropriately trained donor mares in good condition were similar to non-athletic broodmares. (C) 2011 Published by Elsevier B.V.

Ultracold collisions between two light indistinguishable diatomic molecules: Elastic and rotational energy transfer in HD plus HD

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On an Non-Ideal Global and Local Energy Transfer, Using an Electro-Magneto and Magneto-Rheological Dampers

In this paper, we investigated the nonlinear vibrations of a Non-ideal (NIS) electromechanical absorber (NEVA), taking into account a modified mathematical model of (MR) Damper. We observed the presence of the Sornmerfeld effect (it is the steady state frequencies of the DC motor, which it will usually increasing as more power (Voltage) is given to it, in a step-by-step fashion. When a resonance condition it is reached, the better part of this energy it is consumed to generate large amplitude vibrations of the foundation, without sensible change of the motor frequency). The obtained results, by using numerical and analytical simulations, were discussed, in details.

Comments on a nonlinear and nonideal electromechanical damping vibration absorber, Sommerfeld effect and energy transfer

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On energy transfer between vibrating systems under linear and nonlinear interactions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

On energy transfer phenomena, in a nonlinear ideal and nonideal essential vibrating systems, coupled to a (MR) magneto-rheological damper

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)