– This paper presents the optimization of a photovoltaic (PV) water pumping system using maximum power point tracking technique (MPPT). The optimization is suspended to reference optimal power. This optimization technique is developed to assure the optimum chopping ratio of buck-boost converter. The presented MPPT technique is used in photovoltaic water pumping system in order to optimize its e...

The paper analyses the effect of electrohydrodynamic (EHD) pumping on the control of natural circulation loops (NCLs). The two major objectives of the investigation are: finding the optimal configuration of an EHD pump and demonstrating that the NCL flow direction can be inverted by exploiting the EHD phenomena. In the initial experimental set-up, we measured the static pressure rise given by a...

A study of the mechanisms responsible for the infra-red to near infra-red up-conversion in thulium doped silica fibres is presented. Up-conversion luminescence was observed from the H4 level of Tm under 1586 nm pumping into the F4 level. The quadratic dependence of the up-conversion luminescence at 800 nm on the 1800 nm luminescence from the F4 level confirms that the H4 level is populated by a...

Despite decades of speculation, the proton pumping mechanism of complex I (NADH-ubiquinone oxidoreductase) is unknown and continues to be controversial. Recent descriptions of the architecture of the hydrophobic region of complex I have resolved one vital issue: this region appears to have multiple proton transporters that are mechanically interlinked. Thus, transduction of conformational chang...

1 Introduction By circumventing the problem of indirect bandgap, Raman scattering offers a path to optical amplification and lasing in silicon [1]. To create the recently demonstrated silicon Raman lasers [2, 3] nonlinear losses due to absorption by free carriers that are generated by two-photon absorption (TPA) had to be eliminated using pulsed pumping or reverse-biased carrier sweep-out. Even...

Groundwater microbial community samples are traditionally collected using pumping techniques optimized for groundwater chemistry assessment although the impact of groundwater pumping parameters on apparent bacterial community structures (BCS) is not really known. We therefore studied the impact of pumping lift, flow regime and tubing material on BCS, which were analyzed by terminal-restriction ...

the modulation response, relative intensity noise and frequency noise characteristics of qd lasers are investigated theoretically, in presence of an additional optical pumping. it is revealed that the modulation response of qd laser enhances under additional optical beam. by small signal analysis of the carriers' and photons' rates, it is proposed that by injecting excess carriers to ...

Saltwater intrusion and upconing phenomena affect coastal aquifers worldwide. Over-exploitation leads to high salinity levels which threaten sustainable use of these freshwater resources. There is an increasing need to accurately, and practically, model the physics of these coastal pumping systems while also incorporating the relevant economics. We formalize a decision model able to define the ...

We explore an embryonic heart model that couples electrophysiology and muscle-force generation to flow induced using a 2D fluid-structure interaction framework based on the immersed boundary method. The propagation of action potentials are coupled to muscular contraction and hence the overall pumping dynamics. In comparison to previous models, the electro-dynamical model does not use prescribed...