Engineering molecular aggregate spectra

We show that optical properties of linear molecular aggregates undergo drastic changes when aggregates are deposited on a metal surface. The dipole-dipole interactions of monomers with their images can result in strong {re-structuring of both the exciton band and the absorption spectrum, depending on the arrangement of the monomer transition dipoles with respect to the surface.Comment: 4 two-column pages, Proceedings of the 8th International Conference on Excitonic Processes in Condensed Matter, June 22-27, Kyoto, Japa

Analysis and Design of Solar Power System Interface Utility Using ZVS Converter

The solar power generation system with minimal losses, high simplicity and easy control is attempted in this work, by developing a grid-tied zero-voltage switching (ZVS) inverter with a less number of power conversion stages and the least count of passive components, for single-phase applications that are suitable for conversion from low-voltage DC (40-60 V) to line voltage AC (230 VAC; RMS) at average power levels of 175 W and below. The ZVS full-bridge inverter fed from a PV panel is working on higher frequency with an asymmetric auxiliary circuit, which guarantees ZVS at the switching instants of the metal-oxide-semiconductor field-effect transistors (MOSFETs) by supplying the reactive current to these full-bridge semiconductor switches and reducing the switching losses. Checking of the constructional workability and analytical feasibility of the proposed topology with the highest efficiency and the simplest control was the target of this work, which was set on the basis of the results obtained in the MATLAB Simulink environment. The control strategies were planned for the optimum value of the reactive current injected by the auxiliary circuit to guarantee ZVS and use of phase shifted pulsewidth modulation (PWM) with varying frequencies for the full-bridge inverter and half-bridge cyclo-converter. The hybrid maximum power point tracking (MPPT) was part of this plan used to set the power at its maximum value against the environmental changes.Citation: Deshbhratar, R. G., and Renge, M. M. (2018). Analysis and Design of Solar Power System Interface Utility Using ZVS Converter. Trends in Renewable Energy, 4, 83-101. DOI: 10.17737/tre.2018.4.3.005

Operation of Symmetrical and Asymmetrical Two-Phase Induction Motor by Using 3-Leg Voltage Source Inverter

The importance and demand of renewable energy have increased rapidly, especially due to the fact that the fossil fuels are reducing at an alarming rate. Out of the existing sources of renewable energies, solar energy has been very popular due to obvious abundance and convenience. The predominant use of electrical energy is heating, ventilation and air conditioning in residential and industrial sector. Single phase induction motor is widely used for such low-power appliances like pumps, compressors, agriculture equipment’s and blowers. In order to avoid losses and low-starting torque, we intend to use the single-phase induction motor as an asymmetrical two-phase induction motor, which will run on a two-phase supply yielding better efficiency, speed control and power factor. If a three-phase supply is available, Scott-T transformer can be used to get two-phase supply. However, if there is only single-phase supply available, two-phase inverter with Sine Pulse Width Modulation (SPWM) technique can be used. This paper presents the method for two-phase supply using the 3-leg voltage source inverter (VSI) which is used to supply asymmetrical and symmetrical two-phase induction motor. The 16 bit microcontroller dsPIC is used for SPWM signal generation.Citation: Umredkar, S. V., Junghare, A., and Renge, M. (2018). Operation of Symmetrical and Asymmetrical Two-Phase Induction Motor by Using 3-Leg Voltage Source Inverter. Trends in Renewable Energy, 4, 64-76. DOI: 10.17737/tre.2018.4.3.005

Glance behaviours when using an in-vehicle smart driving aid : a real-world, on-road driving study

In-vehicle information systems (IVIS) are commonplace in modern vehicles, from the initial satellite navigation and in-car infotainment systems, to the more recent driving related Smartphone applications. Investigating how drivers interact with such systems when driving is key to understanding what factors need to be considered in order to minimise distraction and workload issues while maintaining the benefits they provide. This study investigates the glance behaviours of drivers, assessed from video data, when using a smart driving Smartphone application (providing both eco-driving and safety feedback in real-time) in an on-road study over an extended period of time. Findings presented in this paper show that using the in-vehicle smart driving aid during real-world driving resulted in the drivers spending an average of 4.3% of their time looking at the system, at an average of 0.43 s per glance, with no glances of greater than 2 s, and accounting for 11.3% of the total glances made. This allocation of visual resource could be considered to be taken from ‘spare’ glances, defined by this study as to the road, but off-centre. Importantly glances to the mirrors, driving equipment and to the centre of the road did not reduce with the introduction of the IVIS in comparison to a control condition. In conclusion an ergonomically designed in-vehicle smart driving system providing feedback to the driver via an integrated and adaptive interface does not lead to visual distraction, with the task being integrated into normal driving

Exciton Dephasing and Thermal Line Broadening in Molecular Aggregates

Using a model of Frenkel excitons coupled to a bath of acoustic phonons in the host medium, we study the temperature dependence of the dephasing rates and homogeneous line width in linear molecular aggregates. The model includes localization by disorder and predicts a power-law thermal scaling of the effective homogeneous line width. The theory gives excellent agreement with temperature dependent absorption and hole-burning experiments on aggregates of the dye pseudoisocyanine.Comment: 11 pages, 3 PostScript figure

The J- and H-bands of dye aggregate spectra: Analysis of the coherent exciton scattering (CES) approximation

The validity of the CES approximation is investigated by comparison with direct diagonalisation of a model vibronic Hamiltonian of $N$ identical monomers interacting electronically. Even for quite short aggregates (N\gtrsim 6) the CES approximation is shown to give results in agreement with direct diagonalisation, for all coupling strengths, except that of intermediate positive coupling (the H-band region). However, previously excellent agreement of CES calculations and measured spectra in the H-band region was obtained [A. Eisfeld, J. S. Briggs, Chem. Phys. 324, 376]. This is shown to arise from use of the measured monomer spectrum which includes implicitly dissipative effects not present in the model calculation

Semiquantitative Classification of Two Oxidizing Gases with Graphene-Based Gas Sensors

Miniature and low-power gas sensing elements are urgently needed for a portable electronic nose, especially for outdoor pollution monitoring. Hereby we prepared chemiresistive sensors based on wide-area graphene (grown by chemical vapor deposition) placed on Si/Si3N4 substrates with interdigitated electrodes and built-in microheaters. Graphene of each sensor was individually functionalized with ultrathin oxide coating (CuO-MnO2, In2O3 or Sc2O3) by pulsed laser deposition. Over the course of 72 h, the heated sensors were exposed to randomly generated concentration cycles of 30 ppb NO2, 30 ppb O3, 60 ppb NO2, 60 ppb O3 and 30 ppb NO2 + 30 ppb O3 in synthetic air (21% O2, 50% relative humidity). While O3 completely dominated the response of sensors with CuO-MnO2 coating, the other sensors had comparable sensitivity to NO2 as well. Various response features (amplitude, response rate, and recovery rate) were considered as machine learning inputs. Using just the response amplitudes of two complementary sensors allowed us to distinguish these five gas environments with an accuracy of ~ 85%. Misclassification was mostly due to an overlap in the case of the 30 ppb O3, and 30 ppb O3 + 30 ppb NO2 responses, and was largely caused by the temporal drift of these responses. The addition of recovery rates to machine learning input variables enabled us to very clearly distinguish different gases and increase the overall accuracy to ~94%

An Algae Bioreactor from Recycle Water bottle for Cultivation of Algae

Abstract: The cultivation of algae provides excellent perspectives for renewable energy production and as a source of 'green' products. Algae cultivation can thus contribute substantially to a reduction of CO 2 emissions. This paper describes systems used to cultivate algae from recycle water bottle for biofuel production. For the better quality of Algae cultivation it required a treatment of Nutrients. In this paper we discussed about the construction of Algae bioreactor from recycle water bottle and the treatments of nutrients (Ammonium sulphate, Urea) which required for cultivation of Algae. Result shows that the Algae cultivated from this Algae bioreactor from recycle water bottle is containing large amount of oil than the Algae grow in a rives, wells, ponds etc