Optimal Parameter Estimation of Solar PV Panel Based on Hybrid Particle Swarm and Grey Wolf Optimization Algorithms

The performance of a solar photovoltaic (PV) panel is examined through determining its internal parameters based on single and double diode models. The environmental conditions such as temperature and the level of radiation also influence the output characteristics of solar panel. In this research work, the parameters of solar PV panel are identified for the first time, as far as the authors know, using hybrid particle swarm optimization (PSO) and grey wolf optimizer (WGO) based on experimental datasets of I-V curves. The main advantage of hybrid PSOGWO is combining the exploitation ability of the PSO with the exploration ability of the GWO. During the optimization process, the main target is minimizing the root mean square error (RMSE) between the original experimental data and the estimated data. Three different solar PV modules are considered to prove the superiority of the proposed strategy. Three different solar PV panels are used during the evaluation of the proposed strategy. A comparison of PSOGWO with other state-of-the-art methods is made. The obtained results confirmed that the least RMSE values are achieved using PSOGWO for all case studies compared with PSO and GWO optimizers. Almost a perfect agreement between the estimated data and experimental data set is achieved by PSOGWO

Nano-terracing on polycrystalline palladium induced via simple heat treatment

This paper concerns formation of terraces on polycrystalline Pd, via heat treatments followed by quenching with gas jets. The driving force for terrace formation is the crystallographic anisotropy of the surface energy. Information is presented regarding the surface topography of the terraces and of the grain boundary regions. Typically, the step heights are about 50 nm and the widths of the faces between them are around 1 μm. It is shown that a measure of control can be exercised over the structures produced, although they are determined by a complex interplay of related effects.This research was supported by the EPSRC (EP/E025862/1) and the European Research Council (grant no. 240446)

Effects of contact resistance and metal additives in finned-tube adsorbent beds on the performance of silica gel/water adsorption chiller

Recently interest in adsorption cooling systems has increased due to their capability to utilise low grade heat sources and environmentally friendly refrigerants. Currently, most of the commercially available adsorption cooling systems utilise granular packed adsorbent beds. Enhancing the heat transfer process inside the adsorbent bed will improve the overall efficiency of the adsorption system. Using recently developed empirical lumped analytical simulation model for a 450 kW two-bed silica gel/water adsorption chiller, this paper theoretically investigates the effects of various adsorbent bed heat transfer enhancement techniques on the adsorption system cooling capacity. Firstly, coating the first adsorbent layer to the metal part and packing the rest of adsorbent granules to eliminate the thermal contact resistance between heat exchanger metal and granules while keeping the same level of permeability. Secondly, adding metal particles to the adsorbent in order to enhance the granules thermal conductivity. The effective thermal conductivity of adsorbent/metal mixtures were determined and validated by comparing it with published experimental data. Also, the combined effect of using both techniques simultaneously was investigated. All these investigations were carried out at various adsorption bed fin spacing. Results of the combined techniques showed that the enhancement in the cooling capacity and system coefficient of performance (COP) increased with increasing the fin spacing ratio to reach maximum of 25% and 10% respectively at fin spacing ratio of 2

An accelerated buoyancy adhesion assay combined with 3-D morphometric analysis for assessing osteoblast adhesion on microgrooved substrata.

An accelerated negative buoyancy method has been developed to assess cell adhesion strength. This method has been used in conjunction with 3-D morphometric analysis to understand the effects of surface topology on cell response. Aligned micro-grooved surface topographies (with a range of groove depths) were produced on stainless steel 316L substrates by laser ablation. An investigation was carried out on the effect of the micro-grooved surface topography on cell adhesion strength, cell and nucleus volumes, cell phenotypic expression and attachment patterns. Increased hydrophobicity and anisotropic wettability was observed on surfaces with deeper grooves. A reduction was noted in cell volume, projected areas and adhesion sites for deeper grooves, linked to lower cell proliferation and differentiation rates and also to reduced adhesion strength. The results suggest that the centrifugation assay combined with three-dimensional cell morphometric analysis has considerable potential for obtaining improved understanding of the cell/substrate interface.Financial support for this work has been provided by the EPSRC (grant GR/R95364/01) and by the ERC (grant No. 240446). The authors are grateful to Dr. Tim Nunney, of Thermo-Fisher Scientific, for carrying out the XPS measurements.This is the final version of the article. It first appeared from Elsevier via https://doi.org/ /10.1016/j.jmbbm.2015.12.03

The impact of product attributes and emerging technologies on firms’ international configuration

International business literature has largely explained the international dispersion of firms’ activities as a choice based on trade-offs between cost minimisation, knowledge seeking, managing transaction costs and maintaining control. By incorporating insights from operations management, we propose a framework that explicitly takes into account products’ physical and knowledge attributes that constrain the viable international configuration options available to firms. Linking the characteristics of a product to the scope for horizontal and vertical decoupling in a value network allows us to re-frame recent discussions in the literature about fragmentation of activities vs tasks and to develop an overall picture of the way industry-specific peculiarities characterise (and also constrain) viable international configurations. We show how our framework can be used to interpret data on the scope for decoupling and dispersion collected from industry experts and elucidate the relationships between configuration options and measures of product characteristics. We then utilise this framework to predict how emerging technologies will reshape the international configuration options available to firms.EPSR