Preparation and characterization of NaBiO3 nanopowders by different methods for photocatalytic reduction of CO2

In this work we prepared NaBiO₃ nanopowders via three synthesis methods (sol-precipitation, dehydration and hydrothermal methods). To evaluate and compare the physical properties of the prepared materials X-ray diffraction analysis, BET measurements, UV–vis spectroscopy and TEM were applied. The results showed changes to the NaBiO₃ crystallinity, the specific surface area and the particle shape and size, depending on the method of synthesis. To determine the photocatalytic efficiency of the prepared materials, we evaluated the photocatalytic reduction of CO₂.     

Data dependent systems technique: a methodology with an application to human systems

The objective of this paper is to introduce the application of Data Dependent Systems (DDS) methodology to the field of ergonomics. Many current techniques in ergonomics utilize static models, which can have significant limitations. DDS is a stochastic modelling and analysis technique that can be used to capture the dynamics of a system through quantitative analysis of the available data. DDS has been successfully applied to the analysis of manufacturing processes and the surfaces generated by those processes. In this research, DDS was used to analyse time-based hand-skin temperature data for the evaluation of two types of glove liners to be used underneath latex gloves. DDS was able to capture the differences between the two glove liners and the two subjects. The implications of the results and the potential of the DDS methodology are discussed.     

Extensions to emergency vehicle location models

This paper is concerned with extending models for the maximal covering location problem in two ways. First, the usual 0–1 coverage definition is replaced by the probability of covering a demand within the target time. Second, once the locations are determined, the minimum number of vehicles at each location that satisfies the required performance levels is determined. Thus, the problem of identifying the optimal locations of a pre-specified number of emergency medical service stations is addressed by goal programming. The first goal is to locate these stations so that the maximum expected demand can be reached within a pre-specified target time. Then, the second goal is to ensure that any demand arising located within the service area of the station will find at least one vehicle, such as an ambulance, available. Erlang's loss formula is used to identify the arrival rates when it is necessary to add an ambulance in order to maintain the performance level for the availability of ambulances. The model developed has been used to evaluate locations for the Saudi Arabian Red Crescent Society, Riyadh City, Saudi Arabia.     

Capturing a Qualitative Model of Network Performance and Predicting Behavior

This paper describes a method for constructingbehavior models of communication networks. The methodutilizes archived quantitative performance data createdby a network management platform to create a Quantitative/Qualitative (Q²)Dynamic System representation. The Q²representation captures the predominant qualitative(symbolic) states of the network, qualitative inputevents and transitions among the states resulting from these events. Thissymbolic model allows the network manager to understandthe current system behavior, and predict future possiblebehaviors. We evaluated the method on two sets of archive data. The method shows promise foruse in network management, including network monitoring,fault detection, prognostication andavoidance.     

Physico‐chemical characterization of date varieties using multivariate analysis

BACKGROUND: The fruit of date palm is consumed as an ideal high‐energy food. It is also used for the treatment of colds, fever, liver and abdominal troubles. Its nutritional composition strongly depends upon variety and ripening stage. A number of varieties are available in Pakistan but little is known about their composition and nutritional characteristics. Inherent moisture, volatile matter, ash, fixed carbon, sugar and mineral metals of seven commercial date varieties (Aseel, Basra, Begun, Janshoor, Mazoee, Rabee and Zaidi) were investigated. The physical and chemical compositions with respect to maturation were also monitored for the Aseel variety. RESULTS: The results showed significant varietal differences in moisture, ash and mineral metal composition when analysis of means was conducted at an alpha level of 0.05. The difference between means was insignificant (P > 0.05) for volatile matter, glucose, fructose and total reducing sugars. All varieties were found to be an excellent source of total reducing sugar (78%), potassium (403–632 mg per 100 g) and calcium (27.41–81.47 mg per 100 g). A gradual increase in total reducing sugar and minerals, especially potassium and copper, was observed with maturation. Variety Aseel was grouped on the basis of maturation using principal component analysis. Local date varieties were separated with 48.63% level of similarity from Iranian variety (29.17%) using Cluster analysis. CONCLUSION: This study provides an overview of the physico‐chemical properties of date varieties. The sample varieties showed significant differences except for sugar and volatile matter. Multivariate analysis was found to be an important statistical tool for the separation of samples on the basis of geographical origin and maturations. Copyright © 2008 Society of Chemical Industry     

Optimal model‐free control for a generic MIMO nonlinear system with application to autonomous mobile robots

In this paper, the design procedure for optimal model‐free control algorithm is presented for the tracking problem of completely unknown nonlinear dynamic systems operating under unknown disturbances. The procedure includes a new structure in the context of model‐free control and data‐driven control algorithms. In the new structure, the unknown nonlinear functions are segmented into 1 unknown linear‐in‐states part and another unknown nonlinear part. The adaptive laws proposed for estimating the unknown system dynamics are regressor‐free estimation methods in which there is no need for regressor parameters and, consequently, the persistent excitation condition is not required anymore. Moreover, the main controller gains are updated online, incorporating the adapted values of linear terms in the system dynamics. A comparative study is presented to show that the proposed optimal model‐free control outperforms the state‐of‐the‐art model‐free control algorithms. In addition, the simulation results for the application of the algorithm on autonomous mobile robots are provided.     

Synthesis and characterization of Ag nanoparticles embedded in PVA via UV-photoreduction technique for synthesis of Prussian blue pigment

Silver nanoparticles doped in polyvinyl alcohol (AgNps/PVA) were synthesized via polymer-promoted reductive reaction of AgNO₃ and PVA under time-dependent exposure to UV radiation. The AgNps/PVA composites were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction, UV–Vis spectroscopy, and transmission electron microscopy to describe the structure, nuclearity, and distribution of Ag Nps within the PVA matrix. The UV–Vis spectrum of AgNps/PVA exhibited a broad surface plasmon absorption around 425–443 nm which originated from the formation of Ag NPs. Surface analysis by XPS indicated that the Ag NPs were grown solely on the PVA surface at UV exposure time of 2 h (2.0AgNPs/PVA). Increasing the UV exposure time to 4 h will cause the transformation of metallic nanosilver to oxidized nanosilver. UV–Vis absorption spectra were in situ recorded to follow the synthesis of Prussian blue (PB) on 2.0AgNPs/PVA (PB@2.0AgNPs/PVA). The colloidal dispersion of 2.0AgNPs/PVA in an acidic medium containing free Fe(III) ions and potassium hexacyanoferrate(III) revealed an additional band centered at 720 nm due to the intermetal charge-transfer absorbance of the polymeric Fe(II)-C-N-Fe(III) of the PB@2.0AgNPs/PVA nanocomposite. Control experiments were shown to involve a spontaneous electron transfer reaction between 2.0AgNPs/PVA and Fe(III) ions, with a concomitant decomposition of hexacyanoferrate(III) and formation of PB was observed. Moreover, IR gave clear cut evidence for the synthesis of PB@2.0AgNPs/PVA from the appearance of a band for the cyano group at 2090 cm^?1.     

Optimal Automatic Generation Control with Hydro,Thermal, Gas,and Wind Power Plants in 2-Area Interconnected Power System

Abstract

This paper explores automatic generation control (AGC) of a more realistic 2-area multi-source power system comprising hydro, thermal, gas, and wind energy sources-based power plants in each control area. The wind power plants (WPPs) have been growing continuously worldwide due to their inherent feature of providing eco-friendly sustainable energy. But, operations of WPPs are associated with system stability problems due to lack of inertia. However, WPPs do not participate in the elimination of mismatch between generation and demand by AGC but disturbance can be injected by the WPPs due to the stochastic nature of wind energy. An optimal controller based on full state feedback control theory is designed to conduct the study. The system dynamic performance analysis is carried out for 1% step load disturbance in corresponding control areas. It is observed that the system dynamic graphs of deviation in area frequency and tie-line power are significantly improved with the implementation of optimal AGC controller compared to GA tuned classical controller. It has also been shown that the WPPs aid the increase in load disturbance when the input wind power reduces but it negates the effect of increase in load disturbance for increase in wind energy to the WPPs.