Parameter estimation for five- and seven-parameter photovoltaic electrical models using evolutionary algorithms

Equivalent electric circuit modeling of PV devices is widely used to predict PV electrical performance. The first task in using the model to calculate the electrical characteristics of a PV device is to find the model parameters which represent the PV device. In the present work, parameter estimation for the model parameter using various evolutionary algorithms is presented and compared. The constraint set on the estimation process is that only the data directly available in module datasheets can be used for estimating the parameters. The electrical model accuracy using the estimated parameters is then compared to several electrical models reported in literature for various PV cell technologies.     

A formal mapping-based approach for distributed schedule coordination on projects

Construction projects involve a large number of participants with overlapping scope of work. Coordination of their activities is usually an iterative manual task undertaken by a general contractor that is often unaware of the detailed constraints of other participants. Project schedules play a key role in this coordination and form the backbone of almost all current approaches to process coordination. However, no single schedule represents the perspective of all participants involved in a project. Rather, each participant keeps in some manner a schedule for its own activities, resulting in multiple schedules that need to be coordinated. The current literature does not support simultaneous reasoning across multiple distributed, overlapping schedules. This paper introduces constructs to formalize the integration of participants’ overlapping schedules that represent the same project tasks, but use a different set breakdown structures and level of detail. Implementation of these constructs allows linking of the master schedule to the other participants’ schedules thereby representing the perspectives of all project participants. This integrated perspective facilitates initial schedule coordination and allows rapid identification of schedule conflicts in response to any schedule changes.     

Infrared Spectroscopy-Based Chemometric Analysis for Lard Differentiation in Meat Samples

One of the most pressing concerns for the consumer market is the detection of adulteration in meat products due to their preciousness. The rapid and accurate identification mechanism for lard adulteration in meat products is highly necessary, for developing a mechanism trusted by consumers and that can be used to make a definitive diagnosis. Fourier Transform Infrared Spectroscopy (FTIR) is used in this work to identify lard adulteration in cow, lamb, and chicken samples. A simplified extraction method was implied to obtain the lipids from pure and adulterated meat. Adulterated samples were obtained by mixing lard with chicken, lamb, and beef with different concentrations (10%–50% v/v). Principal component analysis (PCA) and partial least square (PLS) were used to develop a calibration model at 800–3500 cm⁻¹. Three-dimension PCA was successfully used by dividing the spectrum in three regions to classify lard meat adulteration in chicken, lamb, and beef samples. The corresponding FTIR peaks for the lard have been observed at 1159.6, 1743.4, 2853.1, and 2922.5 cm⁻¹, which differentiate chicken, lamb, and beef samples. The wavenumbers offer the highest determination coefficient R² value of 0.846 and lowest root mean square error of calibration (RMSEC) and root mean square error prediction (RMSEP) with an accuracy of 84.6%. Even the tiniest fat adulteration up to 10% can be reliably discovered using this methodology.     

The optimal solution for the flow of a fourth-grade fluid with partial slip

The steady flow of a non-Newtonian fluid when slippage between the plate and the fluid occurs is considered. The constitutive equations of the fluid are modeled for a fourth-grade non-Newtonian fluid with partial slip; they give rise to nonlinear boundary value problems. Analytical solutions are obtained using powerful analytic techniques for solving nonlinear problems, homotopy perturbation and optimal homotopy asymptotic methods. The results obtained are compared with the numerical results and it is shown that solutions exist for all values of the non-Newtonian parameters. The solutions valid for the no-slip condition for all values of the non-Newtonian parameters can be derived as special cases of the present analysis. Finally the solutions are discussed using a graphical approach.     

Reliability analysis of TLP tethers under impulsive loading

In the present study, reliability assessment of Tension Leg Platform (TLP) tethers against maximum tension (i.e. tension exceeding yield) has been carried out under combined action of extreme wave and impulsive forces. For this purpose, a nonlinear dynamic analysis of TLP has been carried out in time domain. A limit state function for maximum tension (i.e. tension exceeding yield) has been derived employing Von-Mises theory of failure. Using this derived limit state function and responses obtained after dynamic analysis under sinusoidal, half-triangular and triangular impulsive forces, reliability assessment of the TLP tethers has been carried out. Design point, important for probabilistic design of tethers, has been located on the failure surface after solving a constrained optimization problem. To study the influence of various random variables on tether reliability, sensitivity analysis has been carried out. Effects of angle of impact; effect of variable submergence; and effect of material yield strength on tether reliability have also been studied on parametric basis. Effect of uncertainty on overall tether reliability has also been discussed to show the importance of quality control in the various design parameters.     

Reliability analysis of nuclear containment without metallic liners against jet aircraft crash

The present study presents a methodology for detailed reliability analysis of nuclear containment without metallic liners against aircraft crash. For this purpose, a nonlinear limit state function has been derived using violation of tolerable crack width as failure criterion. This criterion has been considered as failure criterion because radioactive radiations may come out if size of crack becomes more than the tolerable crack width. The derived limit state uses the response of containment that has been obtained from a detailed dynamic analysis of nuclear containment under an impact of a large size Boeing jet aircraft. Using this response in conjunction with limit state function, the reliabilities and probabilities of failures are obtained at a number of vulnerable locations employing an efficient first-order reliability method (FORM). These values of reliability and probability of failure at various vulnerable locations are then used for the estimation of conditional and annual reliabilities of nuclear containment as a function of its location from the airport. To study the influence of the various random variables on containment reliability the sensitivity analysis has been performed. Some parametric studies have also been included to obtain the results of field and academic interest.     

Aggregate nonparametric safety analysis of traffic zones

Exploring the significant variables related to specific types of crashes is vitally important in the planning stage of a transportation network. This paper aims to identify and examine important variables associated with total crashes and severe crashes per traffic analysis zone (TAZ) in four counties of the state of Florida by applying nonparametric statistical techniques such as data mining and random forest. The intention of investigating these factors in such aggregate level analysis is to incorporate proactive safety measures in transportation planning. Total and severe crashes per TAZ were modeled to provide predictive decision trees. The variables which carried higher weight of importance for total crashes per TAZ were – total number of intersections per TAZ, airport trip productions, light truck productions, and total roadway segment length with 35 mph posted speed limit. The other significant variables identified for total crashes were total roadway length with 15 mph posted speed limit, total roadway length with 65 mph posted speed limit, and non-home based work productions. For severe crashes, total number of intersections per TAZ, light truck productions, total roadway length with 35 mph posted speed limit, and total roadway length with 65 mph posted speed limit were among the significant variables. These variables were further verified and supported by the random forest results.     

3D numerical investigation of ZnO/Zn hydrolysis for hydrogen production

The current research is focused on the hydrogen production through a two‐step ZnO/Zn thermochemical water splitting cycle. In the present paper, numerical modeling of the second step is conducted using Computational Fluid Dynamics (CFD)2, where steam reacts with zinc to produce hydrogen. The parametric study shows that the hydrogen yield is relatively insensitive to the steam/zinc molar ratio and inversely proportional to the argon/steam molar ratio. For large argon to steam molar ratios, hydrogen yield is relatively insensitive to the inlet temperature of zinc and steam, and increases marginally with an increase in the argon inlet temperature. Five different reactor configurations were evaluated comprehensively. Among all configurations, a cylindrical reactor with a tangential inlet for argon and zinc, and a radial inlet for steam (both in the bottom plane of the reactor) and a tangential outlet in the top plane of the reactor produced the highest hydrogen yield of 88%. Copyright © 2013 John Wiley & Sons, Ltd.     

A study on the synthesis,characterization and properties of polyaniline/magnesium boride nanocomposites

The present paper reports the novel synthesis of polyaniline/magnesium boride (PAni/MgB₂) nanocomposites. Nanowires 50–100 nm in diameter grown by the sol–gel technique were incorporated in the PAni to prepare PAni/MgB₂ nanocomposites, which yielded an enhancement of conductivity by 5 orders of magnitude. PAni was synthesized through the chemical oxidative polymerization method. The composition of the prepared nanocomposites was tunable, i.e. the amount of dopant was varied and the effects on various parameters were observed by different techniques. The morphology of PAni/MgB₂ nanocomposites was determined using SEM. The temperature dependence of the conductivity of all composites was measured in the temperature range 300–450 K and it was observed that samples having a high concentration of MgB₂ show the highest conductivity. The molecular structure of the nanocomposites was further characterized by Fourier Transform IR spectroscopy which showed small structural changes in the backbone of PAni. I?V measurements showed that the current increases on increasing MgB₂ content. UV?visible spectra exposed the occurrence of an indirect optical transition in the composite. © 2013 Society of Chemical Industry     

Numerical investigation of thermal disassociation of ZnO for hydrogen production: Parametric study and reactor configuration

The present research is focused on the two‐step ZnO/Zn thermochemical water splitting cycle for hydrogen production. In the present paper, the numerical modeling of the first step, which involves endothermic reduction of zinc oxide (ZnO), is carried out in a cylindrical reactor using Computational Fluid Dynamics (CFD). The parametric study shows that the fractional conversion of ZnO increases with an increase in the flow rate of ZnO, while it decreases with an increase in the ZnO particle diameter and carrier gas mass flow rate. Six different reactor configurations are also assessed comprehensively. It is observed that a cylindrical reactor with a tangential inlet at the top plane and a tangential outlet at the bottom plane has higher robustness to the variation of various operating parameters with consistently high ZnO fractional conversion. Copyright © 2013 John Wiley & Sons, Ltd.