Journal of Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Optimization of Laser Transmission Joining Process Parameters on Joint Strength of PET and 316 L Stainless Steel Joint Using Response Surface Methodology Mon, 29 Sep 2014 13:31:25 +0000 http://www.hindawi.com/journals/je/2014/197060/ The objective of the present work is to study the effects of laser power, joining speed, and stand-off distance on the joint strength of PET and 316 L stainless steel joint. The process parameters were optimized using response methodology for achieving good joint strength. The central composite design (CCD) has been utilized to plan the experiments and response surface methodology (RSM) is employed to develop mathematical model between laser transmission joining parameters and desired response (joint strength). From the ANOVA (analysis of variance), it was concluded that laser power is contributing more and it is followed by joining speed and stand-off distance. In the range of process parameters, the result shows that laser power increases and joint strength increases. Whereas joining speed increases, joint strength increases. The joint strength increases with the increase of the stand-off distance until it reaches the center value; the joint strength then starts to decrease with the increase of stand-off distance beyond the center limit. Optimum values of laser power, joining speed, and stand-off distance were found to be 18 watt, 100 mm/min, and 2 mm to get the maximum joint strength (predicted: 88.48 MPa). There was approximately 3.37% error in the experimental and modeled results of joint strength. Shashi Prakash Dwivedi and Satpal Sharma Copyright © 2014 Shashi Prakash Dwivedi and Satpal Sharma. All rights reserved. An Investigation on Shape Morphing by Modulus Variation: Forward Approach Thu, 18 Sep 2014 10:56:40 +0000 http://www.hindawi.com/journals/je/2014/706830/ Structural shape deformation, in its conventional way, includes applying forces to a fixed-compliance structure to deform it to certain shapes. Rather than addressing shape control in the established way (applying forces to elastically or plastically deform a structure), this work studies the use of shape morphing, which involves combining applied forces and local modulus changes. Specifically in this paper, a simply supported elastic beam that can exhibit variable compliance behavior is selected as the model. This study focuses on the forward approach of morphing, that is, determining possible beam shapes due to the applied force and modulus variability. The goal is to incorporate variable-modulus materials into a structure model and utilize the controllable modulus change to quantify the morphing of the structure with limited actuator numbers, locations, and force levels. The resulting morphed shapes are quantified in terms of various characteristic parameters. The study demonstrates that a larger, and in some cases nonintuitive, space of shapes becomes possible when modulus change is utilized, for the same set of applied forces. Amin Mohaghegh Motlagh and William W. Clark Copyright © 2014 Amin Mohaghegh Motlagh and William W. Clark. All rights reserved. Microwave Absorption Properties of Double-Layer RADAR Absorbing Materials Based on Doped Barium Hexaferrite/TiO2/Conducting Carbon Black Wed, 17 Sep 2014 08:23:49 +0000 http://www.hindawi.com/journals/je/2014/468313/ In this report, we demonstrate microwave absorption properties of barium hexaferrite, doped barium hexaferrite, titanium dioxide and conducting carbon black based RADAR absorbing material for stealth application. Double-layer absorbers are prepared with a top layer consisting of 30% hexaferrite and 10% titanium dioxide while the bottom layer composed of 30% hexaferrite and 10% conducting carbon black, embedded in chloroprene matrix. The top and bottom layers are prepared as impedance matching layer and conducting layer, respectively, with a total thickness of 2 mm. Microwave absorption properties of all the composites were analyzed in X-band region. Maximum reflection loss of −32 dB at 10.64 GHz was observed for barium hexaferrite based double-layer absorber whereas for doped barium hexaferrite based absorber the reflection loss was found to be −29.56 dB at 11.7 GHz. A consistence reflection loss value (>−24 dB) was observed for doped barium hexaferrite based RADAR absorbing materials within the entire bandwidth. Sukanta Das, G. C. Nayak, S. K. Sahu, P. C. Routray, A. K. Roy, and H. Baskey Copyright © 2014 Sukanta Das et al. All rights reserved. Improved Grid-Scan Localization Algorithm for Wireless Sensor Networks Wed, 10 Sep 2014 09:11:50 +0000 http://www.hindawi.com/journals/je/2014/628161/ Localization is a fundamental and crucial service for various applications in wireless sensor networks (WSNs). In this paper an improved grid-scan localization algorithm has been proposed. In the proposed algorithm, information about 1-hop, 2-hop, and farther neighboring anchors has been collected that estimates the region using 1-hop anchors. Then, this estimated region is divided into a grid array, finding valid grids using 1-hop and 2-hop anchors information. In addition to that the farther anchor information further reduces the valid grids. The proposed algorithm achieves better location estimation accuracy than the existing grid-scan algorithm. Raghava Srinivasa Nallanthighal and Veeranjaneyulu Chinta Copyright © 2014 Raghava Srinivasa Nallanthighal and Veeranjaneyulu Chinta. All rights reserved. New Joining Technology for Optimized Metal/Composite Assemblies Wed, 03 Sep 2014 08:38:48 +0000 http://www.hindawi.com/journals/je/2014/958501/ The development of a new joining technology, which is used to manufacture high strength hybrid constructions with thermoplastic composites (FRP) and metals, is introduced. Similar to natural regulation effects at trees, fibers around the FRP joint become aligned along the lines of force and will not be destroyed by the joining process. This is achieved by the local utilization of the specific plastic flow properties of the FRT and metal component. Compared with usual joining methods—such as flow drill screws, blind and self-piercing rivets—noticeably higher tensile properties can be realized through the novel process management. The load-bearing capability increasing effect could be proved on hybrid joints with hot-dip galvanized steel HX420LAD and orthotropic glass—as well as carbon—fiber reinforced plastics. The results, which were determined in tensile-shear and cross-shear tests according to DIN EN ISO 14273 and DIN EN ISO 14272, are compared with holding loads of established joining techniques with similar joining point diameter and material combinations. Holger Seidlitz, Lars Ulke-Winter, and Lothar Kroll Copyright © 2014 Holger Seidlitz et al. All rights reserved. A Computational Study on the Use of an Aluminium Metal Matrix Composite and Aramid as Alternative Brake Disc and Brake Pad Material Tue, 26 Aug 2014 12:18:12 +0000 http://www.hindawi.com/journals/je/2014/494697/ A computational model for the heat generation and dissipation in a disk brake during braking and the following release period has been formulated. The model simulates the braking action by investigating the thermal behaviour occurring on the disc and pad surfaces during this period. A comparative study was made between grey cast iron (GCI), asbestos, Aluminium metal matrix composite (AMC), and aramid as brake pad and disc materials. The braking process and following release period were simulated for four material combinations, GCI disc and Asbestos pad, GCI disc and Aramid pad, AMC disc and Asbestos pad, AMC disc and Aramid pad using COMSOL Multiphysics software. The results show similarity in thermal behaviour at the contact surface for the asbestos and aramid brake pad materials with a temperature difference of 1.8 K after 10 seconds. For the brake disc materials, the thermal behaviour was close, with the highest temperature difference being 9.6 K. The GCI had a peak temperature of 489 K at 1.2 seconds and AMC was 465.5 K but cooling to 406.4 K at 10 seconds, while the GCI was 394.7 K. Nosa Idusuyi, Ijeoma Babajide, Oluwaseun. K. Ajayi, and Temilola. T. Olugasa Copyright © 2014 Nosa Idusuyi et al. All rights reserved. Numerical Simulation of Effective Properties of 3D Piezoelectric Composites Mon, 18 Aug 2014 11:14:51 +0000 http://www.hindawi.com/journals/je/2014/824806/ The prediction of the overall effective properties of fibre-reinforced piezocomposites has drawn much interest from investigators recently. In this work, an algorithm used in two-dimensional (2D) analysis for calculating transversely isotropic material properties is developed. Since the finite element (FE) meshing patterns on the opposite areas are the same, constraint equations can be applied directly to generate appropriate load. The numerical results derived using this model have found a good agreement with those in the literature. The 2D algorithm is then modified and improved in such a way that it is valid for three-dimensional (3D) analysis in the case of random distributed shorts and inclusions. Linear interpolation of displacement field is employed to establish constraint equations of nodal displacements between two adjacent elements. Ri-Song Qin, Yi Xiao, and Haitian Lan Copyright © 2014 Ri-Song Qin et al. All rights reserved. Solar Assisted Fast Pyrolysis: A Novel Approach of Renewable Energy Production Mon, 18 Aug 2014 09:16:13 +0000 http://www.hindawi.com/journals/je/2014/252848/ Biofuel produced by fast pyrolysis from biomass is a promising candidate. The heart of the system is a reactor which is directly or indirectly heated to approximately 500°C by exhaust gases from a combustor that burns pyrolysis gas and some of the by-product char. In most of the cases, external biomass heater is used as heating source of the system while internal electrical heating is recently implemented as source of reactor heating. However, this heating system causes biomass or other conventional forms of fuel consumption to produce renewable energy and contributes to environmental pollution. In order to overcome these, the feasibility of incorporating solar energy with fast pyrolysis has been investigated. The main advantages of solar reactor heating include renewable source of energy, comparatively simpler devices, and no environmental pollution. A lab scale pyrolysis setup has been examined along with 1.2 m diameter parabolic reflector concentrator that provides hot exhaust gas up to 162°C. The study shows that about 32.4% carbon dioxide (CO2) emissions and almost one-third portion of fuel cost are reduced by incorporating solar heating system. Successful implementation of this proposed solar assisted pyrolysis would open a prospective window of renewable energy. Mohammad U. H. Joardder, P. K. Halder, A. Rahim, and N. Paul Copyright © 2014 Mohammad U. H. Joardder et al. All rights reserved. Evaluation of Texture and Shape Features for Classification of Four Paddy Varieties Mon, 18 Aug 2014 08:43:45 +0000 http://www.hindawi.com/journals/je/2014/617263/ This research is aimed at evaluating the texture and shape features using the most commonly used neural network architectures for cereal grain classification. An evaluation of the classification accuracy of texture and shape features and neural network was done to classify four Paddy (rice) grains, namely, Karjat-6(K6), Ratnagiri-2(R2), Ratnagiri-4(R4), and Ratnagiri-24(R24). Algorithms were written to extract the features from the high-resolution images of kernels of four grain types and used as input features for classification. Different feature models were tested for their ability to classify these cereal grains. Effect of using different parameters on the accuracy of classification was studied. The most suitable feature from the features for accurate classification was identified. The shape feature set outperformed the texture feature set in almost all the instances of classification. Archana Chaugule and Suresh N. Mali Copyright © 2014 Archana Chaugule and Suresh N. Mali. All rights reserved. Numerical Simulation of an Industrial Absorber for Dehydration of Natural Gas Using Triethylene Glycol Sun, 20 Jul 2014 11:53:58 +0000 http://www.hindawi.com/journals/je/2014/693902/ Models of an absorber for dehydration of natural gas using triethylene glycol are presented. The models were developed by applying the law of conservation of mass and energy to predict the variation of water content of gas and the temperature of the gas and liquid with time along the packing height. The models were integrated numerically using the finite divided difference scheme and incorporated into the MATLAB code. The results obtained agreed reasonably well with industrial plant data obtained from an SPDC TEG unit in Niger-Delta, Nigeria. Model prediction showed a percentage deviation of 8.65% for gas water content and 3.41% and 9.18% for exit temperature of gas and liquid, respectively. Kenneth Kekpugile Dagde and Jackson Gunorubon Akpa Copyright © 2014 Kenneth Kekpugile Dagde and Jackson Gunorubon Akpa. All rights reserved. Retracted: Design of Satellite Attitude Control Algorithm Based on the SDRE Method Using Gas Jets and Reaction Wheels Mon, 26 May 2014 13:35:56 +0000 http://www.hindawi.com/journals/je/2014/506489/ Journal of Engineering Copyright © 2014 Journal of Engineering. All rights reserved. The Mechanical and Electrical Effects of MEMS Capacitive Pressure Sensor Based 3C-SiC for Extreme Temperature Thu, 22 May 2014 09:21:03 +0000 http://www.hindawi.com/journals/je/2014/715167/ This paper discusses the mechanical and electrical effects on 3C-SiC and Si thin film as a diaphragm for MEMS capacitive pressure sensor operating for extreme temperature which is 1000 K. This work compares the design of a diaphragm based MEMS capacitive pressure sensor employing 3C-SiC and Si thin films. A 3C-SiC diaphragm was bonded with a thickness of 380 μm Si substrate, and a cavity gap of 2.2 μm is formed between the wafers. The MEMS capacitive pressure sensor designs were simulated using COMSOL ver 4.3 software to compare the diaphragm deflection, capacitive performance analysis, von Mises stress, and total electrical energy performance. Both materials are designed with the same layout dimensional with different thicknesses of the diaphragm which are 1.0 μm, 1.6 μm, and 2.2 μm. It is observed that the 3C-SiC thin film is far superior materials to Si thin film mechanically in withstanding higher applied pressures and temperatures. For 3C-SiC and Si, the maximum von Mises stress achieved is 148.32 MPa and 125.48 MPa corresponding to capacitance value which is 1.93 pF and 1.22 pF, respectively. In terms of electrical performance, the maximum output capacitance of 1.93 pF is obtained with less total energy of 5.87 × 10−13 J, thus having a 50% saving as compared to Si. N. Marsi, B. Y. Majlis, A. A. Hamzah, and F. Mohd-Yasin Copyright © 2014 N. Marsi et al. All rights reserved. Experimental Finite Element Approach for Stress Analysis Sun, 11 May 2014 07:49:09 +0000 http://www.hindawi.com/journals/je/2014/643051/ This study aims to determining the strain gauge location points in the problems of stress concentration, and it includes both experimental and numerical results. Strain gauges were proposed to be positioned to corresponding locations on beam and blocks to related node of elements of finite element models. Linear and nonlinear cases were studied. Cantilever beam problem was selected as the linear case to approve the approach and conforming contact problem was selected as the nonlinear case. An identical mesh structure was prepared for the finite element and the experimental models. The finite element analysis was carried out with ANSYS. It was shown that the results of the experimental and the numerical studies were in good agreement. Ahmet Erklig and M. Akif Kütük Copyright © 2014 Ahmet Erklig and M. Akif Kütük. All rights reserved. Catalytic Ozonation of Phenolic Wastewater: Identification and Toxicity of Intermediates Wed, 07 May 2014 07:21:46 +0000 http://www.hindawi.com/journals/je/2014/520929/ A new strategy in catalytic ozonation removal method for degradation and detoxification of phenol from industrial wastewater was investigated. Magnetic carbon nanocomposite, as a novel catalyst, was synthesized and then used in the catalytic ozonation process (COP) and the effects of operational conditions such as initial pH, reaction time, and initial concentration of phenol on the degradation efficiency and the toxicity assay have been investigated. The results showed that the highest catalytic potential was achieved at optimal neutral pH and the removal efficiency of phenol and COD is 98.5% and 69.8%, respectively. First-order modeling demonstrated that the reactions were dependent on the initial concentration of phenol, with kinetic constants varying from 0.038 min−1  ([phenol]o = 1500 mg/L) to 1.273 min−1 ([phenol]o = 50 mg/L). Bioassay analysis showed that phenol was highly toxic to Daphnia magna (LC50 96  mg/L). Comparison of toxicity units (TU) of row wastewater (36.01) and the treated effluent showed that TU value, after slightly increasing in the first steps of ozonation for construction of more toxic intermediates, severely reduced at the end of reaction (2.23). Thus, COP was able to effectively remove the toxicity of intermediates which were formed during the chemical oxidation of phenolic wastewaters. Mahdi Farzadkia, Yousef Dadban Shahamat, Simin Nasseri, Amir Hossein Mahvi, Mitra Gholami, and Ali Shahryari Copyright © 2014 Mahdi Farzadkia et al. All rights reserved. Stabilization and Tracking Control of Inverted Pendulum Using Fractional Order PID Controllers Wed, 23 Apr 2014 11:42:16 +0000 http://www.hindawi.com/journals/je/2014/752918/ This work focuses on the use of fractional calculus to design robust fractional-order PID (PIλDμ) controller for stabilization and tracking control of inverted pendulum (IP) system. A particle swarm optimisation (PSO) based direct tuning technique is used to design two PIλDμ controllers for IP system without linearizing the actual nonlinear model. The fitness function is minimized by running the SIMULINK model of IP system according to the PSO program in MATLAB. The performance of proposed PIλDμ controllers is compared with two PID controllers. Simulation results are also obtained by adding disturbances to the model to show the robustness of the proposed controllers. Sunil Kumar Mishra and Dinesh Chandra Copyright © 2014 Sunil Kumar Mishra and Dinesh Chandra. All rights reserved. Tidal Hydrodynamics in the Lower Columbia River Estuary through Depth Averaged Adaptive Hydraulics Modeling Tue, 11 Feb 2014 10:05:26 +0000 http://www.hindawi.com/journals/je/2014/416914/ The adaptive hydraulics (AdH) numerical code was applied to study tidal propagation in the Lower Columbia River (LCR) estuary. The results demonstrate the readiness of this AdH model towards the further study of hydrodynamics in the LCR. The AdH model accurately replicated behavior of the tide as it propagated upstream into the LCR system. Results show that the MSf tidal component and the M4 overtidal component are generated in the middle LCR and contain a substantial amount of tidal energy. An analysis was performed to determine the causes of MSf tide amplification, and it was found that approximately 80% of the amplification occurs due to nonlinear interaction between the M2 and the S2 tidal components. Gaurav Savant and Tate O. McAlpin Copyright © 2014 Gaurav Savant and Tate O. McAlpin. All rights reserved. Motion Objects Segmentation and Shadow Suppressing without Background Learning Thu, 23 Jan 2014 15:51:40 +0000 http://www.hindawi.com/journals/je/2014/615198/ An approach to segmenting motion objects and suppressing shadows without background learning has been developed. Since wavelet transformation indicates the position of sharper variation, it is adopted to extract the information contents with the most meaningful features based on two successive video frames only. According to the fact that the saturation component is lower in the region of shadow and is independent of the brightness, HSV color space is selected to extract foreground motion region and suppress shadow instead of other color models. A local adaptive thresholding approach is proposed to extract initial binary motion masks based on the results of the wavelet transformation. A foreground reclassification is developed to get an optimal segmentation by fusion of mode filtering, connectivity analysis, and spatial-temporal correlation. Comparative studies with some investigated methods have indicated the superior performance of the proposal in extracting motion objects and suppressing shadows from cluttered contents with dynamic scene variation and crowded environments. Y.-P. Guan Copyright © 2014 Y.-P. Guan. All rights reserved. Decentralized Scheduling Algorithm for DAG Based Tasks on P2P Grid Wed, 22 Jan 2014 13:04:02 +0000 http://www.hindawi.com/journals/je/2014/202843/ Complex problems consisting of interdependent subtasks are represented by a direct acyclic graph (DAG). Subtasks of this DAG are scheduled by the scheduler on various grid resources. Scheduling algorithms for grid strive to optimize the schedule. Nowadays a lot of grid resources are attached by P2P approach. Grid systems and P2P model both are newfangled distributed computing approaches. Combining P2P model and grid systems we get P2P grid systems. P2P grid systems require fully decentralized scheduling algorithm, which can schedule interreliant subtasks among nonuniform computational resources. Absence of central scheduler caused the need for decentralized scheduling algorithm. In this paper we have proposed scheduling algorithm which not only is fruitful in optimizing schedule but also does so in fully decentralized fashion. Hence, this unconventional approach suits well for P2P grid systems. Moreover, this algorithm takes accurate scheduling decisions depending on both computation cost and communication cost associated with DAG’s subtasks. Piyush Chauhan and Nitin Copyright © 2014 Piyush Chauhan and Nitin. All rights reserved. Performance Evaluation of New Joint EDF-RM Scheduling Algorithm for Real Time Distributed System Wed, 22 Jan 2014 13:02:24 +0000 http://www.hindawi.com/journals/je/2014/485361/ In Real Time System, the achievement of deadline is the main target of every scheduling algorithm. Earliest Deadline First (EDF), Rate Monotonic (RM), and least Laxity First are some renowned algorithms that work well in their own context. As we know, there is a very common problem Domino's effect in EDF that is generated due to overloading condition (EDF is not working well in overloading situation). Similarly, performance of RM is degraded in underloading condition. We can say that both algorithms are complements of each other. Deadline missing in both events happens because of their utilization bounding strategy. Therefore, in this paper we are proposing a new scheduling algorithm that carries through the drawback of both existing algorithms. Joint EDF-RM scheduling algorithm is implemented in global scheduler that permits task migration mechanism in between processors in the system. In order to check the improved behavior of proposed algorithm we perform simulation. Results are achieved and evaluated in terms of Success Ratio (SR), Average CPU Utilization (ECU), Failure Ratio (FR), and Maximum Tardiness parameters. In the end, the results are compared with the existing (EDF, RM, and D_R_EDF) algorithms. It has been shown that the proposed algorithm performs better during overloading condition as well in underloading condition. Rashmi Sharma and Nitin Copyright © 2014 Rashmi Sharma and Nitin. All rights reserved. Fault Tolerant PLBGSA: Precedence Level Based Genetic Scheduling Algorithm for P2P Grid Wed, 18 Dec 2013 16:03:56 +0000 http://www.hindawi.com/journals/je/2013/749132/ Due to monetary limitation, small organizations cannot afford high end supercomputers to solve highly complex tasks. P2P (peer to peer) grid computing is being used nowadays to break complex task into subtasks in order to solve them on different grid resources. Workflows are used to represent these complex tasks. Finishing such complex task in a P2P grid requires scheduling subtasks of workflow in an optimized manner. Several factors play their part in scheduling decisions. The genetic algorithm is very useful in scheduling DAG (directed acyclic graph) based task. Benefit of a genetic algorithm is that it takes into consideration multiple criteria while scheduling. In this paper, we have proposed a precedence level based genetic algorithm (PLBGSA), which yields schedules for workflows in a decentralized fashion. PLBGSA is compared with existing genetic algorithm based scheduling techniques. Fault tolerance is a desirable trait of a P2P grid scheduling algorithm due to the untrustworthy nature of grid resources. PLBGSA handles faults efficiently. Piyush Chauhan and Nitin Copyright © 2013 Piyush Chauhan and Nitin. All rights reserved. Printed Persian Subword Recognition Using Wavelet Packet Descriptors Tue, 12 Nov 2013 15:29:09 +0000 http://www.hindawi.com/journals/je/2013/465469/ In this paper, we present a new approach to offline OCR (optical character recognition) for printed Persian subwords using wavelet packet transform. The proposed algorithm is used to extract font invariant and size invariant features from 87804 subwords of 4 fonts and 3 sizes. The feature vectors are compressed using PCA. The obtained feature vectors yield a pictorial dictionary for which an entry is the mean of each group that consists of the same subword with 4 fonts in 3 sizes. The sets of these features are congregated by combining them with the dot features for the recognition of printed Persian subwords. To evaluate the feature extraction results, this algorithm was tested on a set of 2000 subwords in printed Persian text documents. An encouraging recognition rate of 97.9% is got at subword level recognition. Samira Nasrollahi and Afshin Ebrahimi Copyright © 2013 Samira Nasrollahi and Afshin Ebrahimi. All rights reserved. The Importance of the Model Choice for Experimental Semivariogram Modeling and Its Consequence in Evaluation Process Mon, 07 Oct 2013 14:27:35 +0000 http://www.hindawi.com/journals/je/2013/960105/ Geostatistics was created during the second half of 20th century by Georges Matheron, on the basis of Danie Krige’s and Herbert Sichel’s theories. The purpose of this new science was to achieve an optimal evaluation of mining ore bodies. The interest in geostatistical tools has grown, and nowadays its techniques are applied in many branches of engineering where data analysis, interpolation, and evaluation are necessary. This paper presents an overview of the geostatistics approach in data analysis and describes each operative step from experimental semivariogram calculation to kriging interpolation, focusing and underlining the experimental semivariogram modeling step. To help any data analysts during geostatistical analysis process, an innovative geostatistical software was created. This new software, named “Kriging Assistant” (KA) and developed within the Department of Geoengineering and Environmental Technologies University of Cagliari, is able, with a marginal support of the user, to produce 2D and 3D grids and contour maps of sampled data. A comparison between kriging results obtained by KA and two of the most common data analysis softwares (Golden Software Surfer and ESRI Geostatistical Analyst for ArcMap) is presented in this paper. Reported data showed that KA minimizes interpolation errors and, for this reason, provides better interpolation results. Alessandro Mazzella and Antonio Mazzella Copyright © 2013 Alessandro Mazzella and Antonio Mazzella. All rights reserved. Symbol Error Probability of DF Relay Selection over Arbitrary Nakagami- Fading Channels Thu, 03 Oct 2013 08:31:32 +0000 http://www.hindawi.com/journals/je/2013/325045/ We present a new analytical expression for the moment generating function (MGF) of the end-to-end signal-to-noise ratio of dual-hop decode-and-forward (DF) relaying systems with relay selection when operating over Nakagami- fading channels. The derived MGF expression, which is valid for arbitrary values of the fading parameters of both hops, is subsequently utilized to evaluate the average symbol error probability (ASEP) of -ary phase shift keying modulation for the considered DF relaying scheme under various asymmetric fading conditions. It is shown that the MGF-based ASEP performance evaluation results are in excellent agreement with equivalent ones obtained by means of computer simulations, thus validating the correctness of the presented MGF expression. George C. Alexandropoulos, Paschalis C. Sofotasios, Khuong Ho-Van, and Steven Freear Copyright © 2013 George C. Alexandropoulos et al. All rights reserved. Energy Analysis in Combined Reforming of Propane Mon, 23 Sep 2013 11:57:14 +0000 http://www.hindawi.com/journals/je/2013/301265/ Combined (steam and CO2) reforming is one of the methods to produce syngas for different applications. An energy requirement analysis of steam reforming to dry reforming with intermediate steps of steam reduction and equivalent CO2 addition to the feed fuel for syngas generation has been done to identify condition for optimum process operation. Thermodynamic equilibrium data for combined reforming was generated for temperature range of 400–1000°C at 1 bar pressure and combined oxidant (CO2 + H2O) stream to propane (fuel) ratio of 3, 6, and 9 by employing the Gibbs free energy minimization algorithm of HSC Chemistry software 5.1. Total energy requirement including preheating and reaction enthalpy calculations were done using the equilibrium product composition. Carbon and methane formation was significantly reduced in combined reforming than pure dry reforming, while the energy requirements were lower than pure steam reforming. Temperatures of minimum energy requirement were found in the data analysis of combined reforming which were optimum for the process. K. Moon and Ganesh R. Kale Copyright © 2013 K. Moon and Ganesh R. Kale. All rights reserved. High Temperature Vacuum Annealing and Hydrogenation Modification of Exfoliated Graphite Nanoplatelets Tue, 10 Sep 2013 10:07:20 +0000 http://www.hindawi.com/journals/je/2013/638576/ Highly active defect sites on the edges of graphene automatically capture oxygen from air to form various oxygen groups. A two-step procedure to remove various oxygen functional groups from the defect sites of exfoliated graphene nanoplatelets (GNPs) has been developed to reduce the atomic oxygen concentration from 9.5% to 4.8%. This two-step approach involves high temperature vacuum annealing followed by hydrogenation to protect the reduced edge carbon atoms from recombining with the atmospheric oxygen. The reduced GNPs exhibit decreased surface resistance and graphitic potential-dependent capacitance characteristics compared to the complex potential-dependent capacitance characteristics exhibited by the unreduced GNPs as a result of the removal of the oxygen functional groups present primarily at the edges. These reduced GNPs also exhibit high electrochemical cyclic stability for electrochemical energy storage applications. Xiaobing Li, Sanjib Biswas, and Lawrence T. Drzal Copyright © 2013 Xiaobing Li et al. All rights reserved. Prediction of Matrix Failure in Fibre Reinforced Polymer Composites Tue, 27 Aug 2013 10:52:24 +0000 http://www.hindawi.com/journals/je/2013/973026/ Recent development has enabled fibre and matrix failure in a fibre reinforced composite material to be predicted separately. Matrix yield/failure prediction is based on a Von Mises strain and first strain invariant criteria. Alternative matrix failure criteria for enhanced prediction accuracy are discussed in this paper. The proposed failure envelope formed with basic failure criteria intersects with uniaxial compression, pure shear and uniaxial tensile test data points smoothly. For failure of typical neat resin, significant improvement of prediction accuracy compared with measured material data is demonstrated. For a unit cell with a fibre and surrounding matrix with typical material properties, a FEM analysis indicates a significant improvement in prediction accuracy in the pure shear load case and a marginal improvement in the biaxial tensile load case. This paper also provided a preliminary discussion about the issues when material nonlinearity of the matrix material is involved. J. Wang and W. K. Chiu Copyright © 2013 J. Wang and W. K. Chiu. All rights reserved. A Very Compact AES-SPIHT Selective Encryption Computer Architecture Design with Improved S-Box Wed, 31 Jul 2013 14:02:31 +0000 http://www.hindawi.com/journals/je/2013/785126/ The “S-box” algorithm is a key component in the Advanced Encryption Standard (AES) due to its nonlinear property. Various implementation approaches have been researched and discussed meeting stringent application goals (such as low power, high throughput, low area), but the ultimate goal for many researchers is to find a compact and small hardware footprint for the S-box circuit. In this paper, we present our version of minimized S-box with two separate proposals and improvements in the overall gate count. The compact S-box is adopted with a compact and optimum processor architecture specifically tailored for the AES, namely, the compact instruction set architecture (CISA). To further justify and strengthen the purpose of the compact crypto-processor’s application, we have also presented a selective encryption architecture (SEA) which incorporates the CISA as a part of the encryption core, accompanied by the set partitioning in hierarchical trees (SPIHT) algorithm as a complete selective encryption system. Jia Hao Kong, Li-Minn Ang, and Kah Phooi Seng Copyright © 2013 Jia Hao Kong et al. All rights reserved. Biosorption of Lead Ions from Aqueous Solution Using Ficus benghalensis L. Mon, 29 Jul 2013 09:30:04 +0000 http://www.hindawi.com/journals/je/2013/167518/ Ficus benghalensis L., a plant-based material leaf powder, is used as an adsorbent for the removal of lead ions from aqueous solution using the biosorption technique. The effects of process parameters such as contact time, adsorbent size and dosage, initial lead ion concentration, and pH of the aqueous solution on bio-sorption of lead by Ficus benghalensis L. were studied using batch process. The Langmuir isotherm was more suitable for biosorption followed by Freundlich and Temkin isotherms with a maximum adsorption capacity of 28.63 mg/g of lead ion on the biomass of Ficus benghalensis L. leaves. Venkateswara Rao Surisetty, Janusz Kozinski, and L. Rao Nageswara Copyright © 2013 Venkateswara Rao Surisetty et al. All rights reserved. Planar Monopoles with Different Radiator Shapes for UWB Body-Centric Wireless Communications Thu, 18 Jul 2013 08:56:22 +0000 http://www.hindawi.com/journals/je/2013/683428/ This paper presents a study on the performances of a group of planar monopoles using radiators of different shapes, such as triangle, rectangle, square, annual ring, circle, horizontal ellipse, vertical ellipse, pentagon, and hexagon, for ultra-wideband (UWB) body-centric wireless communications. The planar monopoles have the radiators with microstrip-fed line printed on one side of the substrate and a ground plane on the other side. Simulation studies show that, among these monopoles, the horizontal elliptical, vertical elliptical, and hexagonal monopoles have better overall performances in terms of bandwidth, gain, efficiency, and radiation pattern in free space. A solid-body phantom mimicking human tissue is used for studies of these three monopoles for body-centric communications. Simulated and measured results of these monopoles on the phantom show that the horizontal elliptical monopole achieves the widest impedance bandwidths, highest average peak gain and efficiency, least path loss, best fidelity, and good radiation pattern, making it a good candidate for UWB body-centric wireless communications. Y. Y. Sun, S. W. Cheung, and T. I. Yuk Copyright © 2013 Y. Y. Sun et al. All rights reserved. La Loaded TiO2 Encapsulated Zeolite Y Catalysts: Investigating the Characterization and Decolorization Process of Amaranth Dye Mon, 24 Jun 2013 17:44:20 +0000 http://www.hindawi.com/journals/je/2013/407167/ Lanthanide ions loaded TiO2 encapsulated into Y zeolite catalysts were synthesized and used in sonocatalytic degradation of Amaranth dye in aqueous solution. The support zeolite Y was modified by different loading of Ti and La species using ion exchange method. The sonocatalytic reaction condition was carried out at 10 mg/L initial dye concentration, original pH, 1.5 g/L of catalyst loading with low ultrasonic frequency of 40 KHz. Different characterization techniques were used to reveal the physicochemical characteristics of the catalysts. Successful loading of TiO2 and La/TiO2 into zeolite Y was achieved. The framework of zeolite Y remained unchanged after the loading of TiO2. Titanium species was bound to the framework of zeolite through Ti–O–Si bonds through isomorphous substitution of Si in the zeolite. The ultrasonic degradation of Amaranth dye was enhanced by the TiO2 encapsulation with a maximum degradation efficiency of 50% after 120 min of reaction. However, the activity of the catalyst decreased after the loading of lanthanum. This decrease was attributed to the poor contact between the metal crystallites located on the external surface and the titanium encapsulated into cages of zeolite Y. Atheel Hassan Alwash, Ahmad Zuhairi Abdullah, and Norli Ismail Copyright © 2013 Atheel Hassan Alwash et al. All rights reserved.