ALBERT

Description: In the current study, an attempt has been made to use water hyacinth plant ( Eichhornia crassipes ) as a raw material for production of bioethanol which is then blended with diesel to obtain biodiesel. To investigate the combustion performance, combustion simulation model was developed and compared with experimental results. Further, the combustion performance of bioethanol–diesel blends in diesel engine was evaluated using response surface methodology technique. Bioethanol extracted from water hyacinth is blended with commercial diesel fuel (BED) in different proportions (volume by volume (v/v)), i.e., 5, 10, 15, 20 and 25BED. This study illustrates the investigation of various compression ratio, loads and fuel injection pressures with different proportion of diesel bioethanol blends. The results show that single-cylinder diesel engine is capable to run up to 25 % bioethanol mixed with diesel by volume. The in-cylinder combustion pressure ( P max ) reduces while increasing bioethanol–diesel ratio. At higher engine loads, compression ratio and fuel injection pressure, bioethanol blends produce higher combustion pressure in comparison with pure diesel fuel. At lower load, compression ratio and fuel injection pressure, ignition delay increases and P max reduces. The 5BED (5 % bioethanol + 95 % diesel) and 10BED (10 % bioethanol + 90 % diesel) gave better combustion performance among all the bioethanol–diesel blends.

Description: The main purpose of the present work is the preparation of green dielectrics by solid-state reaction between two perovskites: CaTiO 3 (CTO) and KMgF 3 (KMF). Calcium titanate and potassium magnesium fluoride powders were previously synthesized, respectively, at 850 °C and 700 °C. Several chemical compositions (1– x ) CTO + x KMF were then prepared and dry-milled. The mixtures were pressed into pellets and sintered in free air at 950 °C for 2 h. The obtained ceramics were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA, DTGA) and dielectric measurements (DE). The XRD study revealed the formation of a fluorinated perovskite solid solution with general formula Ca 1– x K x (Ti 1– x Mg x )O 3–3 x F 3 x (CKTMOF) in the initial composition range 0 ≤  x  ≤ 0.20. The diffraction peaks of CKTMOF oxyfluorides were indexed in an orthorhombic lattice, and no significant change was observed in the unit cell parameters with increasing KMF amount. On the other hand, the addition of KMF to CTO allowed the ceramic’s densification at low temperature. The shrinkage increased from 1.9 % ( x  = 0) to 9.5 % ( x  = 0.20), and the grain’s size of the various ceramics was in the range 0.5–5μm. Several thermal phenomena were detected by DSC and DE. No weight loss and no peak were depicted on the TGA and the DTGA curves over all the temperature range investigated; therefore, the phenomena observed by DSC and DE could be ascribed to phase transitions. These dielectrics could be of interest for the fabrication of class I capacitors; however, the losses have to be improved.

Description: The paper presents an effective nonlinear adaptive switching non-local filter for the restoration of impulse-corrupted digital images by using distinct impulse detection and correction stages. The correction scheme of the filter adaptively switches between details-preserving non-local mode and signal restoration-based local mode to facilitate high fidelity in the restored image. The non-local filtering operation replaces impulses with a remote pixel that better suits the local image conditions. The algorithm works in this non-local mode only when there are sufficient uncorrupted pixels in the local neighborhood of the corrupted pixel to be replaced. Otherwise, the algorithm replaces impulsive pixels with the median of the uncorrupted pixels from the local neighborhood. Experimental results from various impulse noise levels support the improved performance of the proposed algorithm over other algorithms both subjectively and objectively.

Description: The aim of this study was to investigate the oxidation behavior of nickel-base superalloys (Inconel 600 and Hastelloy C-22) by the determination of the oxidation rates of alloys at elevated temperatures and at ambient air. The cyclic oxidation method was adapted by heating of alloys periodically in still air at 900, 1000 and \({1100^\circ{\rm C}}\) followed by cooling at ambient temperature. The weight change measurement was recorded during the cyclic oxidation tests. The X-ray diffraction and microstructure study were also used as characterization methods to illustrate the properties of studied alloys and oxide film that formed on the surface of oxidized alloys. Inconel 600 and Hastelloy C-22 showed their ability to develop a uniform protective oxide film. The oxide film that formed on both alloys was chromia oxide Cr 2 O 3 with smaller amount of spinel oxide NiCr 2 O 4 . The results of the weight gain measurements suggest that the oxidation kinetics of both alloys follows the parabolic behavior during the experimental tests. Also both alloys at \({1100^\circ{\rm C}}\) exhibited severe spallation of oxide film with linear decreasing in the weight change measurements. The p-kp model was implemented to describe the subsequent cyclic process of oxide growth and spalling.

Description: Contaminated high-voltage (HV) insulators in polluted areas may lead to flashovers if they are not cleaned periodically. Flashover often leads to lengthy service outages and thus has a considerable impact on power system reliability. Therefore, an accurate prediction of the contamination level of HV insulators is vital. In this study, a MATLAB-based algorithm for predicting the contamination level is proposed. The algorithm uses the extracted features (in this work, linear algebraic features) from images captured by digital cameras as an input to a neural network. When compared to existing methods reported in the literature, the designed neural network correlates successfully the captured insulator images and the contamination level when tested on unseen insulators.

Description: In this paper, analytical and simulation models were used to analyze the performance of the erbium-doped fiber amplifier in terms of its pump power, erbium-doped fiber length, overlap factor, erbium ions concentration, and input signal power. The analytical-based analysis was performed using MATLAB software, whereas the simulation-based analysis was performed using Optisystem software. Both the analytical- and simulation-based results agreed well. For example, both confirmed the followings: Maximum gain can be reached at a shorter fiber length as the overlap factor and erbium ions concentration increase; the gain is independent of the pump power at values of erbium-doped fiber lengths ≤10m; that almost equal erbium-doped fiber gains can be obtained as the pump power approaches its highest value and that the gain seems to be equal at low values of input signal powers; however, it starts to saturate as the input signal power increases.

Description: This paper presents the fabrication process of hybrid Mg/(Al 2 O 3p + SiC p + Gr p ) metal matrix composite on developed gas injection liquid stir casting setup. In this study, the microstructure, grain morphology and the presence of elements in fabricated composite are investigated through high-resolution scanning electron microscope and X-ray diffractometer. A gas injection liquid stir magnesium metal matrix composite casting setup has been designed, fabricated and utilized for the purpose. Different sets of experiments have been performed in a controlled environment of argon gas. Different tests have been conducted on the prepared Mg-MMC to investigate its physical and mechanical properties of the prepared MMC. The test results reveal that the micro-hardness of hybrid Mg/(4wt% SiC p + 2wt% Al 2 O 3p + 1wt% Gr p ) MMC is about 1.5 times of the pure Mg-matrix. Tensile strength of fabricated hybrid Mg/(8wt% SiC p + 2wt% Al 2 O 3p + 1wt% Gr p )-MMC has also increased to 1.4 times of pure Mg-matrix. From the results, it is concluded that the developed gas injection stir Mg-MMC casting setup can be effectively utilized for the fabrication of hybrid Mg/(Al 2 O 3p + SiC p + Gr p )-MMC and can be used for many industrial and engineering applications.

Description: Coal drying is a quite important process from both burning efficiency and granulation perspective. Therefore, coal drying experimentation processes always attract researchers from various fields. Those experiments are quite costly since they require expensive laboratory equipment and considerable labor hour. Even if the costs of experiments are tolerable, often long experiment periods and large number of experimentation will cause serious problems for prompt academic results. During the analysis of experiments, researchers convert the results into graphical form. However, when creating charts, it is observed that some of the results diverge from the others abnormally marking some measurement as outliers. In such cases, experiments should be repeated to eliminate the effects of these abnormalities. Due to high costs and time constraints, repetition of an experiment is not preferable in general. To predict the accurate values for outliers and overcome issues generated by these abnormalities, artificial neural network (ANN) is employed in this study and tolerable deviations and acceptable experimental costs are reached by using ANN.

Description: The first-order shear deformation theory is used to study the static behavior of a piezoelectric bimorph beam with delamination between its layers. This delamination is taken with several lengths and locations along the beam with different boundary conditions. The results show that the shape of the axial displacement field is not affected by either the length of the debonded zone or the variation in the ambient. However, this shape is deformed when an electrical field is applied.

Description: Greenhouses are complex and nonlinear systems in which the inside temperature and humidity are deterministic parameters for the optimal growth of the plants. Several control methods have been developed to get an optimized microclimate. Physically both parameters are strongly coupled; hence, this paper proposes a novel fuzzy controlling method considering the temperature and humidity’s coupling effects; the controller is based on a validated greenhouse physical model and an evaluation of the correlation of both parameters. The results show the high performance of the decoupling method and the effectiveness of the fuzzy controller to manage the inside climate while saving energy.

Description: This paper investigates the implementation and performance limits of conventional and odd-harmonic repetitive controllers used for current control of two-level grid-connected inverter. This research is motivated by the relatively poor performance of classical (PI) controller when utility voltage has high harmonic distortion. Repetitive controllers (RCs) have the ability to track or reject periodic signals. However, their effectiveness is limited severely by the scarce bandwidth of the plant. To address this issue, the relationship between plant bandwidth and the converter’s LCL filter is also investigated. In addition, the effects of variation in parameters of low-pass filter used in RC loop on the performance of the system are studied. Odd-harmonic repetitive controller (ORC) is used to overcome the excessive memory requirement in RC implementation. The performance of RC and ORC is tested for different total harmonic distortion (THD) values of utility voltage. The results show that RC improves steady state error and THD of the output current. Also, RC is found to be robust under variations in output-side inductance.

Description: In this study, Cu matrix nanocomposites with reinforced CNT particles (0.5–5 wt %) were successfully fabricated by employing flake powder metallurgy with warm-pressing and sintering technology at 950 °C for 2 h. The properties of the composite powders were analyzed using a hall flowmeter for the apparent density, a laser particle size analyzer for the particle size and a scanning electron microscopy for the powder morphology. The green and sintered density, hardness and electrical conductivity of Cu–CNT contact materials were determined utilizing Archimedes method, a hardness analyzer and an electrical conductivity measurement device, respectively. The results showed that both consolidation ability and electrical conductivity of the Cu–CNT nanocomposites decreased by increasing the CNT content. The lowest density was 6.3 and 6.73 g/cm 3 for green and sintered Cu–5wt% CNT nanocomposites, respectively, while the highest density value was 8 and 8.57 g/cm 3 for green and sintered Cu–0.5wt% CNT nanocomposites, respectively. The measured conductivity values were 74.56 IACs for 0.5 wt% CNT- reinforced sintered samples and decreased up to 46.3 for 2 wt% CNT-reinforced sintered samples and then decreased to 5.3 IACs for 5 wt% CNT-reinforced sintered samples.

Description: Steam injection in heavy oil reservoirs does not only change the fluid properties, but also affects the interfacial tension of aqueous phase/hydrocarbon and the wettability of sand/hydrocarbon systems. Understanding the alteration of those properties is crucial for a successful steam injection, and it is expected to play an important role in heavy oil recovery from sands. However, studies on the measurements of interfacial properties of steam, heavy oil, and sand systems have not been well documented in the literature. This paper describes a new experimental technique and procedure which have been developed for generating steam within a small optical cell at high saturated pressure and temperature conditions. After that, image processing technique was applied to measure the interfacial tension of heavy oil/steam and the contact angle of heavy oil/steam/quartz systems. They have several advantages which are fast, relatively cheap and reliable. They potentially would have a wide range of applications in steam injection such as measuring the rock wettability, examining the effects of steam acidity and steam quality, and optimization for the purposes of prevention and/or reduction in damages to the formation. The experimental results indicate that steam injection has caused the alteration of interfacial properties. Interfacial tension measured in steam/heavy oil systems tends to decrease, while contact angle measured in quartz/heavy oil/steam systems tends to increase at saturated temperature and pressure conditions. As the aging time increases, the quartz’s wettability changes from mixed-wet to more oil-wet.

Description: A heterogeneous network (HetNet) is one of the core features that have been introduced in the LTE-advanced standardization to meet the predicted requirements for higher data rates and capacity. An integrated picocellular–macrocellular networks is part of such HetNets. Most previous works have concentrated on solving the picocellular–macrocellular networks challenges, including optimal picocell deployment, interference coordination, cell association methods and frequency resource allocations. However, the resource allocation control issue for LTE macrocells integrated with underlying picocells owned by different operators that can allow macrocell user (MU) accommodation has not been investigated deeply. Therefore, this paper proposes and analyzes a new resource allocation control framework called a preemption-based call admission control scheme (PCAC) for integrating independent underlying picocells with macrocell networks. The proposed scheme aims to utilize the resource blocks (RBs) of picocells efficiently to improve MU performance by allowing its MU visitors to utilize unused picocell RBs without any degradation for picocell users. A developed simulation model and a multi-dimensional continuous-time Markov chain (CTMC) model are used to model and analyze the proposed PCAC. The analytical model developed considers a limited-size buffer to store MUs, buffer time out and resource reservation. The MU connection-level performance metrics, including dropping and blocking probabilities, are derived and studied. The results indicate that better connection-level parameters for MUs and higher throughputs are achieved by using the proposed PCAC.

Description: A type of zirconia-toughened alumina (ZTA) ceramic-lined composite steel pipe was fabricated by using self-propagation high-temperature synthesis and centrifugal casting technique. The microstructure and phase constituents of ZTA ceramic layer were analyzed by means of optical microscope, scanning electron microscope and X-ray diffractometer (XRD). The fracture toughness of ceramic layers and mechanical shock of Al 2 O 3 and ZTA ceramic-lined composite pipes were measured using Vickers indentation microfracture method and the repetitive impacting method. The results show that the phase constituents of ZTA ceramic layer were Al 2 O 3 , FeAl 2 O 4 and t-ZrO 2 phases, and no m-ZrO 2 phase was detected by XRD. Addition of ZrO 2 reduced the width of Al 2 O 3 dendrites and led to formation of a microstructure with fine ZrO 2 particles distributed at boundaries of Al 2 O 3 dendrites. The fracture toughness was increased from 0.56 MPa m 1/2 of Al 2 O 3 ceramic layer to 5.74 MPa m 1/2 of ZTA ceramic layer. The mechanical shock resistance at the center of the ceramic-lined composite pipe was increased from twice to 19 times after addition of ZrO 2 into the Al 2 O 3 matrix.

Description: This paper presents the development of Holy Quran recitation recognizer. The decoder of recognizer performs sub-word level recognition at phoneme. The paper demonstrates high recognition accuracies achieved by applying incremental refinements to the HMM models of the phonemes during the training stage. The Maximum- likelihood (ML) criterion is first applied for HMMs parameter estimation, which produces average recognition accuracies of up to 83 %. This is followed by discriminative technique of minimum phone error (MPE), which is applied to minimize recognition error at phoneme level. Investigation shows that MPE based acoustic models improve generalization. The results show 3–4 % improvement in recognition accuracies, which are promising when compared with the case of ML approach applied alone.

Description: The use of enzymes in different industrial sectors increased significantly due to huge industrialization. Different types of protease and amylase are randomly used in industries including food, textile, and paper. For this purpose, purification of extracellular protease and amylase produced by the bacterium, Corynebacterium alkanolyticum ATH3 (Acc. No. JX656749) isolated from the distal intestine of a freshwater fish, Anabas testudineus , was carried out using column chromatography. The specific activity of protease and amylase significantly increased with each step of purification and finally became 93.73 and 88.1 U/mg protein with a purification fold 26.03 and 44.94, respectively. The sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed molecular weight of purified protease and amylase was ∼17 and ∼28 kDa, respectively. To the authors’ knowledge, this is the first report of ∼17 kDa protease and ∼28 kDa amylase from the bacterial strain C . alkanolyticum ATH3. Further, enzyme activity was also evidenced by zymography analysis. The enzymes acted optimally at pH 7.5–8.0 and temperature 35–45  \({^{\circ}{\rm C}}\) , respectively. So, due to cheapest source, these two enzymes are very important for various purposes in industrial sectors.

Description: In this paper, the exponential synchronization problem of delayed coupled switched neural networks with individual node and network topology switching is investigated. By using the matrix decomposing approach and the switched system comparison principle, several synchronization criteria for such complex dynamical networks are obtained. Firstly, under the assumption that all subnetworks are self-synchronized, a sufficient condition is derived in terms of an algebraic inequality. Then, when some subnetworks are not self-synchronized, based on the maximal dwell time length, the exponential synchronization criteria are given in terms of algebraic inequalities. Finally, examples are provided to illustrate the effectiveness of the theoretical results.

Description: The classifications of uncertain data turned into one of the dreary procedures in the data mining domain. The uncertain data have tuples with distinctive probability distribution, which helps to find similar class of tuples. When we consider an uncertain data, the feature vector will not be a single valued but a function. In this paper, we proposed fuzzy entropy and similarity measure to characterize the uncertain data through binary decision tree algorithm. Fuzzy entropy is used to find the best split point for the decision tree to handle the uncertain data. Similarity measure is used to make the better decision for the uncertain data with high accuracy. Initially, fuzzy entropy for each feature vector is calculated to select the best feature vector. Then, best split is selected from the selected feature vector. With the help of trained uncertain data, the binary tree starts to grow. Once the split point is selected, then the constructed decision tree is evaluated by the testing phase of uncertain data. The testing data are subjected to the trained decision tree to obtain the classified data. The experimental analyses are made to evaluate the performance of the proposed FUDT approach. Proposed FUDT algorithm is compared with the existing classification algorithm UDT in terms of accuracy and running time. The experimental analysis finalizes that our FUDT algorithm outperforms the existing UDT algorithm.

Description: Fast pyrolysis was used to convert waste biomass into bio-oil, which has a benefit of storage and transportation with the potential as a fossil oil substitute. Pakistani cotton stalk was pyrolyzed in a bench-scale bubbling fluidized bed reactor. The effect of reaction conditions such as temperature and feed size on the bio-oil, char and gas yields was investigated. The optimal pyrolysis temperature for the production of bio-oil was 490 ° C which gave the maximum yield (36 wt%) of product at feed size of 1.0 mm. Bio-oil yield increased with the increase in temperature, while the yield of char decreased. The various properties of bio-oil attained under these pyrolysis conditions were defined. Chemical composition of bio-oil was determined using FTIR and GC–MS analysis, and major chemical compounds were phenols, carboxylic acids, ketones, aldehydes, furans and sugars.

Description: The Lower Senonian Matulla Formation is well developed in the southern and central Gulf of Suez. It can be subdivided into three depositional units (M1–M3). An obvious unconformity separated the middle unit (M2) from the upper unit (M3). The three units are corresponding to a second-order depositional sequence. This sequence consists of two systems tracts; the lower lowstand systems tract consists of slope fan, followed by a prograding complex. An erosion surface separated the lower from the upper transgressive systems tract. The Matulla Formation is mostly composed of sandstones and pelagic sediment intercalations. Such intercalations show obvious facies change throughout the study area, causing further subdivision of the Matulla Formation into seven rock types (RT1–RT7). The petrophysical reservoir evaluation has been achieved via determination of the effective porosity, permeability, shale content, water saturation and net-pay thickness from the environmentally corrected well log data. It indicates that the Matulla Formation can be considered as a good reservoir quality especially in its lower unit and sometimes in its middle unit as well. The available core data indicate a lithological heterogeneity of the studied Matulla Formation. Lithologically, it can be subdivided into four petrophysical and lithological facies; namely, they are sandstones, ferruginous sandstones, argillaceous sandstones and limestones. The best petrophysical properties were assigned for the ferruginous sandstones with good to excellent porosity, very good to excellent permeability, and poor to fair flow zone indicator.

Description: The purpose of the present work was to study the potential biotechnological use of Dunaliella species isolated from the solar saltern of Sfax (Tunisia). D. salina was grown in artificial seawater (3.4M NaCl) under a constant temperature (25°C) and light ( \({265 {\mu}{\rm mol} {\rm photons} {\rm m}^{-2} {\rm s}^{-1}}\) ). The maximal cellular density was about \({4.66\times 10^{6} {\rm cells/ml}}\) , and the growth rate ranged between 0.13 and 0.16 doublings/day. Chlorophyll a reached \({52.32 \pm 0.12 {\rm mg/l}}\) in the exponential phase. Protein and carbohydrates content reached maximum values in the lag phase ( \({52.4 \pm 0.2}\) and \({5.7 \pm 0.34\,{\rm mg/l}}\) , respectively). The maximal values of total lipids content were obtained at the decline phase ( \({92 \pm 0.87\,{\rm mg/l}}\) ). In addition, during this study, the analyses of the fatty acids profile have shown the presence of essential fatty acids that accumulate in D. salina during the stress phase.

Description: This study investigates the variations in the mechanical properties of high-damping rubber bearings HDRBs on the dynamic response of multi-story seismic base-isolated building subjected to bidirectional near-fault ground motions. Variations in the mechanical properties of HDRB due to temperature, aging and scragging recovery are considered. Nonlinear response analyses of a six-story base-isolated building subjected to seven pairs of bidirectional near-fault ground motions with pulse type were conducted using finite element software. The nonlinear force–deformation behavior of isolator is modeled using a bilinear hysteretic curve considering non-deteriorating and deteriorating properties. Results of analyses are compared in terms of bearing displacement, base shear, force–displacement loops, top floor absolute acceleration and story drift. It was observed that the seismic response of base-isolated multi-story building is significantly influenced by the variation in mechanical properties of rubber bearing seismic isolators.

Description: In this paper, we propose an efficient heterogeneous network (HetNet) architecture with coexisting small cell technology to provide capacity and coverage expanding in 3G and 4G mobile networks. A hierarchical HetNet layout comprises of three layers macro-, metro- and femtocell. The metrocell is employed as an intermediate layer in the integrated femtocellular/macrocellular network, which operates in a complementary fashion, in order to manage the handover traffic between the edge layers. Consequently, the femtocell serves indoor traffic activity of femto users, while metrocell serves the outdoor traffic activities as well as the overflow traffic from femtocells. The overall HetNet is completed with the macrocell overlay layer, which serves only the macro users and the overflowed traffic from the underlay layer. Then, we develop a realistic teletraffic framework in order to evaluate the performance of the proposed HetNet. We show both analytically and by simulation that the proposed HetNet architecture with coexisting small cells is able to offload traffic from traditional macrocellular network in terms of reducing the blocking probability.

Description: Nanofluids have opened a new arena for researchers in the field of heat transfer with their exceptional heat transfer characteristics. Enhanced thermal conductivity and improved stability are the principal advantages of nanofluids for its applications in heat transfer. This paper presents an experimental investigation on the stability of silver–water nanofluids prepared by dispersing 0.1 % volume fraction of polyvinylpyrrolidone-coated silver nanoparticles in distilled water with and without the addition of surfactants. The surfactants used in the present study are polyvinylpyrrolidone and sodium dodecyl sulfate. The stability of the nanofluids was estimated from sedimentation time, pH value, zeta potential and particle size distribution. Thermal conductivity of the nanofluids was measured by thermal property analyzer. It has been found that the stability of nanofluids is influenced predominantly by the size of the particle and the surfactant characteristics. The stability of nanofluid increases with the decrease in the size of nanoparticles. Also, the stability increases with sodium dodecyl sulfate as surfactant as against polyvinylpyrrolidone. However, enhancement in the thermal conductivity is found to be higher with polyvinylpyrrolidone than with sodium dodecyl sulfate.

Description: A combined pseudo-homogeneous and fractal geometry model was developed to simulate the process of a integrated technology. The technology was proposed to replace heat pipes and WFGD, which is based on the theory that liquid membrane and droplets grow in size by vapor heterogeneous condensation with they acting as nucleation centers and then the grown droplets are removed efficiently by using integrated diverse combinations of condenser pipes and a highly efficient scrubber. The model has been approached useful for both analyzing results and aiding in design of the technology by conducting a two-dimensional steady-state model by means of infinitesimal analysis, incorporating with the models of whole fine particles absorption efficiency of a regularly arranged liquid membrane and droplets column group, and the models of geometric classifications for liquid and solid based on the fractal dimension identified by different structural of radius of gyration of liquid–solid interface transition zone. The predicted values were also compared with the experimental results, and they are in excellent agreement. The results showed that: When the fractal dimension d f is 0.3, the calculation result is the most closer to actual experiment parameter. The PM 2.5 diffusion volume flux value V w ranges from 22 and 45 mm/s.

Description: In this paper, two classes of V-band substrate integrated waveguide (SIW) bends operating in V-band frequency in the range [58–63 GHz] for the \({90^{\circ}}\) SIW bend with inductive via and in the range [57–68 GHz] for the circular SIW bend and corporate \({1\times4}\) and \({1\times8}\) SIW power dividers that provide equal power split with high isolation in all output ports operating in V-band [45–80 GHz] are presented and studied. The advantages of the SIW technique are its low profile, low cost, mass production, ease of fabrication and full integration with planar circuits. All the SIW bend topologies are optimized and designed to operate in the V-band frequency range. The bends and dividers are analyzed using the two-dimensional finite element method (2D-FEM). The analysis was performed in H-plane using a powerful full-wave method based on the two-dimensional finite element method (2D-FEM) programmed under MATLAB environment. The return losses, transmission coefficients and the field’s distribution are exposed in this paper. To validate our results numerically, a comparison is made and the obtained results are compared with those given by the CST Microwave Studio. It is observed that the simulation computation time is reduced with good accuracy since the discretization was done only in two dimensions.

Description: With the increasing demand of data communication in Internet and electronic commerce environments, security of the data is the prime concern. Large-scale collaborative wireless mobile ad hoc networks may face attacks and damages due to harsh behavior of the malicious nodes. To protect the systems from the intrusion of the attackers, security of the system has to be improvised. In researches involving the designing of the intrusion detection system (IDS), performance efficiency of the system is bound to be compromised. For an effective data communication process in the secured system, there is a need for better IDS without reducing the performance metrics. Intrusion detection is the progression of monitoring node movements and data transmission events that occur in a system for possible intrusions. Distributed denial of service (DDOS) attacks are the primary threat for security in the collaborative wireless Mobile Ad hoc networks. The attacks due to DDOS are much severe when compared to the non DDOS attacks. So proper preventive measures are necessary to detect and revoke such attacks. Our proposed approach involves trust-based evaluation wherein the intrusion detection is done using secured trust evaluation policies. In this paper, a novel IDS is designed using the trust evaluation metrics. This is used for the detection of the flooding DDOS attacks in the networked architecture. The proposed system combines the existing Firecol-based security procedures with Dynamic Growing Self-Organizing Tree Algorithm in the trust evaluation-based environment. Simulation results show that the Trust-based IDS is found to be better in terms of Security metrics viz. Detection probability and Performance metrics viz. Packet Data Ratio, Average Delay, Throughput and Energy Consumption.

Description: In the present study, electrochemical process was studied via removal of diazinon (O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate) as an insecticide/ acaricide organic case study. Influences of three operational parameters including initial ferrous ion concentration, initial hydrogen peroxide concentration, and initial diazinon concentration were measured and optimized in diazinon removal process. Response surface methodology (RSM) was used to design the experiments. The experimental data collected in a laboratory-scaled batch reactor equipped with four graphite bar electrodes as cathode and an aluminum sheet electrode as an anode. Quantitative analysis of diazinon was done with gas chromatography equipped with flame photometric detector. Disperse liquid–liquid microextraction was used prior to gas chromatography in order to extraction and preconcentration of diazinon from aqueous media to extraction phase. Acetone and chlorobenzene were used as disperser and extraction solvent, respectively. Maximum diazinon removal efficiency of 87% (0.85mg mass removal) in C 0 of 2mg/L and 80% (120mg mass removal) in C 0 of 300mg/L was achieved under different experimental conditions. The obtained experimental data were used for model building by RSM approach. Finally, optimization process was carried out using RSM algorithm.

Description: A reconfigurable bandwidth antenna is proposed. A Vivaldi antenna is used in the design due to its wideband capability, moderate high gain and symmetrical radiation patterns in the E and H planes. To vary the frequency bandwidth of the Vivaldi, two pairs of resonator rings have been integrated along the elliptically shaped slot line. The resonator rings are deactivated or activated with the aid of switches to yield either a wideband frequency of 1–2.8 GHz or two narrower frequencies with different bandwidths at 2.6 GHz, respectively. This principle of bandwidth reconfigurability can be potentially put into use in OFDMA-related applications such as LTE since there are multiple sub-carriers which are aggregated based on the rate needs of the user at each instance ranging from 1.4 to 20 MHz. The simulation results are obtained using CST microwave studio, and the results show good agreement with the measured results.

Description: A redundant repairable system having provision of S dissimilar warm standby units and a repair facility is studied. The concepts of common cause failure, switching failure, reboot, repair delay and imperfect repair are taken into account to develop Markov model and facilitating the reliability indices of machining system operating under machining environment. Using appropriate transition rates, Chapman Kolmogorov equations governing the model are constructed to obtain the transient probabilities of the system states. Further, system reliability indices are explored by establishing the explicit expressions in terms of transient probabilities. Runge–Kutta fourth-order technique is applied to perform the numerical simulation and to explore the sensitivity of the various metrics including the availability and failure frequency, with respect to different system parameters.

Description: This paper presents an implementation and performance analysis of a three-phase distribution static compensator (DSTATCOM) for various compensations in a system with static and dynamic loads. Under static loading condition, DSTATCOM is used for reactive power compensation, harmonic elimination and load balancing. During dynamic loading condition, induction machine is considered as a dynamic load by operating it as motor/generator and the dynamic reactive power support capability of DSTATCOM is explored. Synchronous reference frame theory is utilized for reference signal generation and hysteresis pulse width modulation switching is employed for firing pulse generation, which are implemented in field-programmable gate array (FPGA). All the tasks in FPGA are realized as independent modules to build the system with the capability to reconfigure the hardware for any other application with similar requirements. The proposed FPGA implementation utilizes reduced amount of reconfigurable resources and works without a dedicated personal computer. The experimental results prove that the implemented control technique makes the supply current sinusoidal and the supply power factor close to unity.

Description: In this paper, the problem of designing a new iterative learning control has been investigated for a class of strict-feedback nonlinear systems subject to both structured and unstructured uncertainties and dynamic disturbances. The considered systems are assumed to perform the same operation repeatedly under alignment condition. Simple learning mechanisms are proposed to estimate the unknown state-dependent nonlinear functions satisfying local Lipschitz conditions. By using the concept of command filtered backstepping, the problem of the explosion of complexity existing in conventional backstepping is eliminated and the proposed controller is greatly simplified. Lyapunov-like functional method is used to prove the boundedness of all signals of the resulting closed-loop system and the convergence of the tracking errors to zero over iterations. Simulation results are provided to show the effectiveness of the proposed control scheme.

Description: Owing to the interesting challenges in the design of control systems that involve friction force, this paper proposes a new approach to the design of robust control system against friction. The proposal is motivated by the criticism aroused against the model-based friction compensation approaches such as the need for detailed friction model, accurate observer-based friction estimation, and issues of design complexity. The proposal utilizes the inherent robustness and relative design simplicity of the integral sliding mode control to attain closed-loop system robustness against friction effects if the maximum bound of friction is known. The use of ISMC provides closed-loop system robustness without the need for detailed friction modelling or accurate observer-based friction estimation and therefore simplifies closed-loop system design complexity significantly. The friction force in a tutorial example is considered to demonstrate the robustness of the proposed algorithm.

Description: This paper illustrates an efficient controller design technique for the control of a laboratory setup, known as two-rotor aerodynamical system (TRAS). A decentralized control of TRAS using control scheme known as fixed-structure \({H_{\infty}}\) control is presented in this paper. TRAS is a multi-input–multi-output system having strong coupling between horizontal and vertical planes. The main focus of this paper is to design a reduced-order, robust controller for TRAS with a fixed structure. First, the nonlinear model is linearized and then system is decoupled into horizontal and vertical planes. Two independent SISO controllers are designed for both planes using proposed control approach. Comparison is made between conventional \({H_{\infty}}\) and fixed-structure \({H_{\infty}}\) controller design techniques under the influence of different command inputs. The performance of controllers under the effect of external disturbance is also taken into account to show the effectiveness of the proposed approach. In spite of having reduced order, the proposed approach has shown significant improvement toward tracking performance and disturbance rejection as compared to conventional \({H_{\infty}}\) approach.

Description: The objective of this paper is to use the recently proposed galaxy-based search optimization algorithm to enhance the capacity of a multiple input multiple output (MIMO) system with rectangular arrays at both communication ends (transmitter and receiver). This new optimization tool has been recently introduced and is a metaheuristic technique inspired by the dynamics of galactic arm spirals. It is characterized by its robustness, immunity to local optima trapping, relative fast convergence and ease of implementation. The idea is to extend the results obtained for the one-dimensional array geometry to the two-dimensional case. The purpose is to find out which array geometrical dimensions produce the highest capacity value. Compared to the linear array case, promising capacity values are found using the two-dimensional arrays which suggests their deployment in future MIMO communication systems.

Description: In this study, the effect of operating parameters such as cell orientation and ambient temperature with three different types of planar and ducted cathode designs of air-breathing fuel cells (ABFCs) is investigated. Membrane electrode assemblies with varied (10, 30, 40 and 50 %) hydrophobisation on cathode side and 10 % hydrophobisation on anode side are fabricated. The paper throws light on the performance of fuel cell with varied hydrophobisation on cathode side of the fuel cell. It is found that vertical channel orientation is the best orientation for an ABFC to operate due to its higher performance in both ducted and planar cathode designs. Also, based on the results, it can be concluded that the ambient temperature has a significant effect on the performance of an ABFC.

Description: High-intensity noise not only hurts body and mental health of workers, but also covers sound signs of accidence. To increase the sound absorption and noise reduction performance of axial auxiliary fan noise silencers, the noise strength and frequency distribution of the ambient medium casing of an FBYNo3.0/2.2 (II) axial auxiliary fan were investigated. The noise characteristics at the inlets and outlets were analyzed. Based on this study, a new auxiliary fan bell-type muffler was designed, and its noise elimination ability was tested. The results showed that on the surface of the auxiliary fan casing, the noise intensity exhibited a “V” font distribution in that the maximum noise intensity was located in the air outlet and the minimum noise intensity was located in the middle part of the fan. Mid- and low-frequency noise was presented primarily at the outlets. However, intermediate- and high-frequency noise was presented primarily at the inlets. The muffler performance test revealed that the installation of a muffler can dramatically reduce the intensity of the auxiliary fan’s noise. The mean decrease in noise intensity for various positions was 14 dB (A). The noise elimination rate of the muffler was over 15 %. This decreased level of noise was less than the Chinese national standard for maximum noise intensity, 85 dB (A). In addition, optimizing the noise frequency of the inlets and outlets by decreasing the intermediate- and high-frequency noise of the inlets and the intermediate- and low-frequency noise of the outlets can lead to the greatest noise reduction.

Description: A detailed study for the stresses around internally pressurized cylindrical vessel–cylindrical nozzle junctures is carried out using the finite element method. Based on thin shell theory, two simplified expressions (functions of the vessel–nozzle geometrical ratios) of stress concentration factor (SCF) are obtained: one for the main vessel and the other for the nozzle, respectively. The analysis was also used to study the location of maximum stresses at the juncture as well as provide a more accurate presentation of design charts than the \({\rho}\) -SCF plots. Verification is made using some established models available in the literature.

Description: To analyze the centrifugal pump NS32 using numerical model and predicting the performance of a fluid flow in complexes geometry, we conduct several numerical simulation with different turbulence models. To evaluate the effect of turbulence model on the flow characteristics, the k- \({\varepsilon}\) , SST and SST-CC turbulence models were tested. The simulations have been made using the multiple reference frames (MRF) technique to take into account the impeller–volute interaction. The computational domain is composed of two parts, a stator (volute) and a rotor (impeller). The impeller–volute interaction has been simulated using the frozen–rotor interface model for the steady-state calculations and the Rotor–Stator model for the unsteady ones. The distributions of velocity and pressure are computed using the Reynolds-Averaged Navier Stokes approach for a wide range of operating flow rates. To analyze the internal flow, simulation was carried out for several relative positions between the impeller blades and the volute tongue. In fact, the pressure fluctuations were numerically measured at five locations along the impeller and compared to experimental measurements. In addition, the unsteady pressure head evolution versus time was followed up. Then, an experimental validation of global and local characteristics of the pump was carried out.

Description: Nowadays, many researchers have become interested in simulating the manipulation of biological micro/nanoparticles by means of the atomic force microscope. However, in practice, this matter has run into many obstacles, and there are still numerous unknowns and ambiguities regarding the interactions in bioenvironments between different biological micro/nanoparticles with complex and precise shapes. In the past, many simulation works have been performed on the manipulation of biological particles, and most of these works have been conducted on various particles with presumed spherical, and sometimes cylindrical, shapes. But, as we know, the real biological particles have different and complex forms. Therefore, in this paper, first, gold nanoparticles and three different biological particles such as yeast, deoxyribonucleic acid and platelet, which have different shapes, are introduced as the target particles in the manipulation process, and then, the simulations are performed by considering a crowned roller geometry for these particles, and the critical force and time of manipulation in air, water, alcohol and plasma environments are computed. Finally, by reducing the length of the cylindrical section of the crowned roller and bringing the shape closer to a sphere, the obtained results are compared with the existing results for the manipulation of spherical particles and validated.

Description: In the present study, nonlinear modeling of color and chemical oxygen demand (COD) removal of Basic Blue 3 as a fairly toxic textile dye by photocatalytic degradation using \({{\rm TiO}_{2}}\) was investigated. A three replicates and one duplicate of Box–Behnken design with 45 runs, with three factors and three levels of catalyst concentration of 0.5–1.5 g/L, initial dye concentration of 20–100 mg/L, and initial pH of 3–11 were set to quantify the explanatory variables. ANOVA results showed that the best-fit multi-nonlinear regression models were cross-validated \({(R^{2}_{\rm pred})}\) accounting for 99.98–99.79 % and were expressed \({(R^{2}_{\rm adj})}\) accounting for 99.88–99.85 % of variation in decolorization (color removal) and mineralization (COD removal), respectively. In total, 0.51 g/L of \({{\rm TiO}_{2}}\) , 100 mg/L of initial dye concentration, and initial pH of 7 were established as optimum operating parameters by leave-one-out optimization that resulted in 88.61 and 79.03 % for color and COD removal, respectively. 88.78 % of color removal and 76.95 % of COD removal were determined by cross-validation experiments at optimum conditions. Results showed that optimum point determination was successful.

Description: This study presents a thermal analysis for a novel type of solar air heater. The thermal performance of a solar air collector having conical springs on the absorber plate is determined experimentally. A flat absorber plate (Type I) and the absorber plate with mounted conical springs (Type II) are designed and constructed, and their thermal performance is tested in the collectors. Experiments are performed for air mass flow rates of 0.06 and 0.07 kg/s. Thermal efficiency and collector outlet temperature are the main indicator for determining thermal performance. The efficiencies and energy distribution ratios are determined and compared for the collectors. The results of the experiments show that a substantial enhancement in the thermal efficiency is obtained with conical springs. Also, to this thermal efficiency increases with the rise of mass flow rate.

Description: Sudden flow changes in confined pipe systems generate transient flow (waterhammer) conditions accompanied with very high or sometimes very low pressures traveling back and forth in the system. Depending on the magnitude of those pressures, pipe collapse or pipe bursting may take place at the weakest points of the system, resulting in costly damages as well as loss of human lives in some cases. In general, it may be encountered in the penstocks of hydropower plants, water transmission lines and water networks, etc. It is essential that the safe operation guidelines of the hydropower plants be defined accurately, in advance. To achieve that, detailed numerical simulations should be done with reliable software. In some cases, even physical modeling may also be necessary. In the present study, waterhammer problems in the penstocks of Yahyali Wind-Hydro Hybrid Plant are investigated (the construction of the plant has not started yet). Time-dependent flow conditions in the penstocks are simulated by the help of computer software. It solves nonlinear differential equations by using the method of characteristics that uses the principles of finite difference method. Firstly, hydraulic transients for various operational cases are investigated using some scenarios. Then, a surge tank, protective device, for waterhammer, is added to the system, and for the same operational cases, hydraulic transients are studied again.

Description: In several distributed environments, users can decrypt a secret message using a certain number of valid attributes or credentials. Attribute-based encryption (ABE) is the most promising technique to achieve such fine-grain access control. In recent years, many ABE schemes have been proposed, but most of them are constructed based on the concept of pairing and secret sharing scheme. This paper aims at presenting a pairing-free threshold-based ABE scheme (PT-ABE) over multiplicative group. The propose work is secured under the standard decisional Diffie–Hellman (DDH) assumption, and both error-tolerant and collusion-free. The scheme does not consider random oracle operation to prove its security. We compare the PT-ABE scheme with other relevant ABE schemes and find that our scheme is much more efficient and flexible than others. Besides, we propose a protocol based on PT-ABE scheme and show that PT-ABE is perfectly suitable in cloud environment to provide cloud security. To the best of our knowledge, the proposed scheme should be implemented in real- life distributed scenarios, as it is well secured, flexible and perform better than existing ones.

Description: Disinfection of the water in the drinking water supply network is usually done by injecting chlorine to the treated water before it is pumped into the network for distribution. However, such an injection process may not be sufficient to ensure that the chlorine residual throughout the network is within the standard limits. Usually, the residual chlorine is reduced as water moves through the pipe network, due mainly to its reaction with a variety of materials in the bulk water and from the pipe wall. Reduction in residual chlorine in the water supply network may lead to degradation of water quality and, thus, poses potential microbial risks to humans. To meet water quality standards, it is recommended to maintain residual chlorine throughout the water supply network within the desirable levels. This paper presents an optimization model based on the hydraulic simulation model (EPANET) and mixed integer linear programming technique for optimal locations and scheduling of booster chlorination in a real water supply network located in Al-Khobar, Saudi Arabia. The results demonstrate better performance with reduced doses of chlorine when booster chlorination is applied to the water distribution network. The findings may assist in reducing chlorine doses, which is likely to reduce human exposure to potentially harmful disinfection by-products in drinking water.

Description: The problem of output feedback stabilization of a class of under-actuated benchmark nonlinear systems is discussed. The proposed method utilizes an extended high gain observer (EHGO)-based sliding mode control (SMC) technique to control a class of nonlinear systems which may have unstable zero dynamics. Starting with Lagrangian model of the system and using a suitable coordinate transformation, a generalized normal form representation is derived which decouples the system into an internal and external dynamics. The internal dynamics is utilized to derive an auxiliary system and the full-order EHGO thus obtained is used for estimation of derivative(s) of the system output that are further used in design of an output feedback control law. It is shown that the proposed output feedback controller stabilizes the system and convergence of estimated states is demonstrated with suitable selection of observer parameters. The proposed control scheme is applied to a benchmark nonlinear system, namely inertia wheel pendulum (IWP), in order to demonstrate the efficacy of the technique by simulation.

Description: This paper investigates the dynamics analysis and robust control law design for the proposed schematic design of electric unicycles. The schematic design of the proposed unicycle possesses a supportive seat for the rider and is also equipped with a handling rod for maneuvering, similar to a Segway device. First, this paper conducts an analysis and comparison of the dynamics properties and derivation of the nonlinear governing equation for the unicycle. Next, it emphasizes the development of an input-constrained robust controller design for the proposed configuration of the electric unicycle. The issues investigated in this paper include the dynamics property analysis and comparison, nonlinear dynamics derivation, robust control diagram formulation, controller synthesis regarding linear matrix inequalities (LMIs), and time response simulations and discussions. In this control law design via LMIs, the desired performances of: (1) relative stability or decay rate for command tracking capability; (2) disturbance attenuation for robustness against uncertainty parameters; and (3) an accommodation of control effort constraints under the regulation or command tracking of certain initial state condition are investigated and demonstrated using time response simulations of the controlled unicycle dynamics.

Description: This paper proposes an implementation of a practical model-free path planning and path following algorithm for a non-holonomic indoor wheeled mobile robot using multiple cameras and a decentralized fuzzy logic controller. The proposed algorithm is divided into three stages. The first stage uses the multi-stencils fast marching (MSFM) path planning method. In general, the path resulted from the direct implementation of fast marching methods does not guarantee to be safe or smooth. Subsequently, the robot can touch corners, walls and other obstacles. The proposed algorithm adds a preprocessing stage before the MSFM planning method, based on robot dimensions in order to solve such problem. The second stage uses the visual information extracted from the images captured by multiple cameras, in order to estimate the position and orientation of the mobile robot at each frame. The third stage uses a decentralized control strategy, with three identical proportional derivative-like fuzzy logic controllers (PD-like FLC) connected in parallel, as a path follower to keep up the robot on the desired path. The obtained experimental results in this paper show that the developed design is capable of estimating the shortest path efficiently, while avoiding obstacles and guiding the robot to follow the path in real time.

Description: Groundwater of Wadi Nu’man (30 km southeast of Mecca city) of high radon-222 ( \({^{222}}\) Rn) content, emanated directly from the bed rock into the water reservoir, has been analyzed for lead-210 ( \({^{210}}\) Pb) and polonium-210 ( \({^{210}}\) Po), the comparatively long- lived \({^{222}}\) Rn progenies, to study the effect of the continuous \({^{222}}\) Rn emanation on the accumulation of both radionuclides in this water. Emanation of \({^{222}}\) Rn directly from rock to water may be affected seasonally by atmospheric temperature and pressure; therefore, \({^{222}}\) Rn and \({^{222}}\) Rn progenies were reanalyzed in seasonal samples of the same wells. The obtained results showed \({^{210}}\) Pb and \({^{210}}\) Po activity levels ranging from 〈6 to 29.9 and from 0.6 to 18.2 mBq/L, respectively, which was far below the recorded level of their parent radionuclide \({^{222}}\) Rn (10.9–99.7 Bq/L). The data have been discussed in detail.

Description: A ground plane reduced circular microstrip antenna resonating at multiband of frequencies 3.5, 5.2, 6.3 and 8.4 GHz is developed. The proposed antenna gives a wide impedance bandwidth of 75% in the frequency range 3.2 to 7 GHz, covering a part of the UWB operating frequency range. The antenna is coaxially fed, supported by a rectangular strip above the ground plane. The effect of strip width on the variation in impedance bandwidth of the proposed antenna is studied using artificial neural networks, and a comparative study is made. A \({2\times2}\) multiple input multiple output system is designed using the developed antenna, and the mutual coupling of the proposed antenna system is analyzed for various separations and frequencies by using artificial neural networks.

Description: Artificial intelligence has recently drawn the attention of explorers to predict the physical, chemical and mechanical properties of normal-strength concrete (NSC) and high-strength concrete (HSC). This study presents gene expression programming (GEP) and regression analysis (RA) for modeling the modulus of elasticity \({(E_{\rm c})}\) from the compressive strength \({(f_{\rm c})}\) values of NSC and HSC. In order to create the models, experimental results of NSC and HSC are collected from the published literature. The evaluated results by training, testing and checking of the GEP and RA models are compared with the results obtained from the experimental studies, the formulations presented by some national building codes and the formulations proposed by some authors available in the literature. These comparisons and statistic results show that GEP and RA models are very effective methods for calculating the \({E_{\rm c}}\) from \({f_{\rm c}}\) of NSC and HSC.

Description: Pectin lyase degrades pectic substances that are complex polysaccharides of middle lamella and primary cell walls of plants. In this study, alkaline thermostable pectin lyase from Aspergillus niger strain_WHAK1 was produced on wheat bran and citrus pectin in submerged culture. Pectin lyase was purified by ammonium sulfate fractionation, gel filtration and ion-exchange chromatography, and 76.5 purification fold was obtained. Optimum pH and temperature values of pectin lyase were 8.0 and 40°C at 60min, respectively. The enzyme was stable for 17 months at 4°C. K m and V max values were found to be 5.2mg/mL and 0.2(mmol/min) −1 mL, respectively. Molecular weight of pectin lyase was nearly 23.3 kDa. Effects on PL activity of metal ions (NaCl, KCl, CaCl 2 , MgCl 2 , CoCl 2 , CuCl 2 .H 2 O, FeCl 3 .6H 2 O, ZnSO 4 .7H 2 O, (NH 4 ) 2 SO 4 , MnSO 4 ), amino acids ( l -tryptophan, l -cysteine hydrochloride monohydrate, l -arginine monohyd rate), ascorbic acid, citric acid monohydrate, EDTA and resorcinol were studied. The presence of FeCl 3 , CaCl 2 and ascorbic acid significantly enhanced relative pectin lyase activity (%). The purified pectin lyase induced viscosity reduction in fruit juice samples, and it was effective for clarification of fruit juices. Pectin lyase showed substrate preference against fruit juice samples.

Description: Development of sustainable concrete has now become a mandatory requirement today due to environmental problems posed by the production of conventional concrete. Many researchers focused their research toward finding alternate materials for cement, sand, steel, etc., and came out with good results. This paper focuses on feasibility of developing sustainable concrete using bamboo as infill, stiffener, and combination of infill and reinforcement in the wall panels. In addition, low-density polyethylene waste also tried as infill material with bamboo as diagonal member. The structural property of bamboo was studied for replacing the conventional steel by designing the wall panels with lower stiffness and weight to avoid the catastrophic effect. The strength and behavior of infill wall panels for different infill cases were studied under uniaxial in-plane loading. Parameters such as maximum load carrying capacity, load–deflection characteristics, and cost effectiveness of bamboo-based wall panel system were considered in the present study. From the experimental results, it was understood that bamboo-based wall panel behaved as a ductile member and failed after due to the formation of micro-cracks. Wall panel specimens were failed with an out-plan buckling and resisted the force such that the sudden collapse was avoided. It was concluded that an infill wall reduced lateral and vertical deflection, thereby decreasing the probability of collapse. Hence, an infill wall panel could be used as a substitute for conventional wall panel.

Description: In this paper, we propose and evaluate the behavior of a new cognitive amplify-and-forward relaying scenario where the multiple primary users utilize orthogonal spectrum bands. Using orthogonal bands aims to reduce the interference between users as in the downlink transmission in cellular networks where a base station transmits the data of different users using orthogonal frequency bands. In the proposed scenario, the spectrum of the primary user whose channel enhances the secondary system performance is shared with the secondary users. In this paper, the low-complexity switch-and-examine diversity combining relaying scheme is used to select among the secondary relays. In this scheme, the relay whose end-to-end signal-to-noise ratio (SNR) satisfies a predetermined switching threshold is selected instead of the best relay to forward the source message to destination. Approximate expressions are derived for the outage probability and average symbol error probability of the studied system assuming Rayleigh fading channels. Also, the ergodic channel capacity is numerically calculated in this paper. Furthermore, to simplify the achieved expressions and to get more insights about the system behavior, the system is studied at the high SNR values where approximate expression is derived for the outage probability in addition to the derivation of the diversity order and coding gain of the system. The achieved results are validated by Monte Carlo simulations. Main findings illustrate that the diversity order of the studied system is the same as its non-cognitive counterpart and it is independent of the primary network. In contrast to the existing systems where the same spectrum band is utilized by different primary users, increasing the number of primary users in the proposed scenario enhances the overall behavior via improving the coding gain.

Description: Thin films of polycrystalline lead sulfide (PbS) have been deposited on glass substrates by chemical bath deposition at 20 ± 1  ° C in alkaline solutions. Aqueous solutions of lead nitrate (Pb(NO 3 ) 2 ), potassium hydroxide (NaOH), thiourea (CS(NH 2 ) 2 ) and sodium thiosulfate (Na 2 S 2 O 3 ) were used together for the first time to obtain thin films of PbS. The chemical kinetics was investigated according to the amounts of Pb 2+ concentrations measured by atomic absorption spectroscopy during the precipitation of PbS. It was found that sodium thiosulfate had an inhibitor effect for alkaline solutions. The structures of the films were characterized by X-ray diffractometer and showed that all the films had a galena-type cubic structure. The morphological characteristics of the PbS thin films were studied by scanning electron microscope and revealed that when the Na 2 S 2 O 3 compound was used, the shape of the nanoparticles changed from the polymorphic form to the pyramidal form and pinhole-free PbS thin films could be produced.

Description: Cardiovascular disease is a serious threat to human life, especially when a sudden attack occurs, so real-time patient monitoring is crucial. Recent advances in health care and technology have led to equipment such as mobile micro-electro-mechanical systems, which can be used for more accessible public healthcare services. Electrocardiogram (ECG) data are traditionally used to investigate and monitor heart activities. However, the necessary electronic logic tags and (wireless) signal transmissions in a mobile healthcare device are susceptible to noise, which can result in false interpretations. Consequently, this study proposed a novel, low-complexity method for generating an optimized ECG wave suitable for mobile architecture. We first apply a bi-quad, high-pass filter to adjust baseline drifts. Then, a Savitzky–Golay filter smoothes the raw ECG, and moving variance and integral filters with thresholds are used to determine the QRS complex. We compared the results of the proposed technique to those from the moving average, Savitzky–Golay, PRASMMA, and Pan–Tompkins algorithms, using the well-known QT and MIT-BIH databases, and human subjects. The method was implemented on a mobile device integrating an open ECG platform as a prototype for real-time ECG monitoring systems.

Description: In many of the recent earthquake events, the collapse of low engineered or deficient reinforced concrete buildings is the major cause of wide spread disaster. After Kashmir earthquake (2005), the pre-earthquake construction and owner built construction is thought to be under immense risk. Thus, the vulnerability assessment of existing reinforced concrete buildings is strongly recommended to mitigate the associated seismic damage. Aim of this study is to develop vulnerability curves for low engineered structures typical to Pakistan. Two typical gravity load reinforced concrete frames with insufficient detailing are considered, and capacity-related (geometric and material) uncertainties are incorporated to account for the probabilistic nature of vulnerability. Framework developed by earlier studies is used for assessment which shows the buildings fail in a brittle manner due to brittle failure modes and underestimation of damage by GESI reports.

Description: In this work, passive behaviour and semiconducting properties of AZ80 Mg alloy in phosphate buffer solutions of various pH values ranging from 10.69 to 13.05 were studied. Corrosion and passive current densities measured from potentiodynamic polarization plots, defect density drawn from Mott-Schottky analysis, and finally the resistance and capacitance of the passive films estimated from electrochemical impedance spectroscopy (EIS) were all determined. Potentiodynamic polarization results indicated that increasing pH led to decrease both corrosion and passive current densities. Mott-Schottky analysis revealed that the passive films displayed n -type semiconductive characteristics and the donor densities increased with increasing the pH from 10.69 to 13.05. EIS results showed that the thickness of the passive film increased with increasing the pH. In conclusion, increasing pH values offered better conditions for a thicker passive film formation on AZ80 Mg alloy in phosphate buffer solutions with higher protection behaviour.

Description: In this paper, we propose MinDroid, a user-centric preventive policy enforcement system against SMS malware in Android devices. The design of MinDroid takes into consideration the user’s little understanding of the Android permission system. This can be done by deriving the policy rules from the behavioral model of the malicious SMS applications rather than adopting user-defined rules. MinDroid requires user intervention only during the first T time units from the application installation time. The user during this time period is notified to accept or reject the SMS-sending operations. MinDroid execution is specified as a finite state machine, and its security properties are formally proven using Metric Temporal Logic. We also show that MinDroid is resilient against threats trying to compromise its correct functionality. In addition, an analytical study demonstrates that MinDroid offers good performance in terms of detection time and execution cost in comparison with intrusion detection systems based on static and dynamic analysis. The detection efficiency of MinDroid is also studied in terms of detection rate, false positive rate, and ROC distance. A prototype implementation of MinDroid is tested under Android emulator.

Description: Straddling between two contrasting structural features, the High-Atlas in east and the Tadla plain in west, the Beni-Mellal region has a diversified and enormous potential in terms of natural resources, especially building materials and ornamental rocks. The material quarries became widespread and represent one of the significant economic activities in the region. The aim of this study was to develop a GIS-database that includes several themes (layers) in order to properly locate all exploited quarries in the Beni-Mellal region and to analyze its relationship with geology, hydrographic and road networks, and market area. The material extraction takes place by the open-pits in rivers and by the quarries in the Atlas piedmont. The majority of aggregate such as sand and gravel is produced from alluvial deposits, flood plains, and stream terraces located along the Oum Er-Rbia and Oued Derna Rivers and its tributaries. The quarries located in the Atlas piedmont produce crushed rock aggregates from limestone and brecciated dolomite rocks of Lias age. More easily accessible, they could provide long-term quarry material production (in tonnage and quality), meeting the needs of the inhabitants of the region. Also, the Beni-Mellal Atlas region offers huge reserves ornamental rocks, namely travertine and limestone onyx deposited in the dolomite and coral-reef limestone of Lias.

Description: Comprehensive studies to determine the level of predisposition of Saudi environment to many micro-contaminants are scanty. To improve on the available literature, an attempt was made here to determine concentrations of six species of organotins in water samples collected from 17 coastal sites in the Eastern Province of Saudi Arabia. These sites were grouped into three sampling stations: Near Dammam Corniche, King Abdulaziz Port (Inside), and King Abdulaziz Port (Outskirts). The samples were extracted using solid-phase extraction and then derivatized by propylation using Grignard reagent. Analytes were separated and quantitatively determined on gas chromatography–mass spectrometric system using selected ion monitoring mode. Recoveries for 0.1 μ g L −1 spiked sea water samples were between 81 and 89 %, and limits of detection of 5.2–11 ng/L were estimated at S / N  = 3. Total organotin concentration found at each station was averaged at 3.70 μ g L −1 . The individual species detected and quantified as the butylated species were tributyltin (0.14–1.9 μ g L −1 ), dibutyltin (0.11–0.70 μ g L −1 ), and monobutyltin (0.13–1.5 μ g L −1 ). For the phenylated tins, triphenyltin (0.12–1.9 μ g L −1 ), diphenyltin (0.21–1.9 μ g L −1 ), and monophenyltin (0.11–0.62 μ g L −1 ) were determined in the samples. These determinations had %RSD of 6.1–11.5 % for the different analytes. Using ratios of tributyltin and triphenyltin to their respective degradation products, fresh input of these micro-contaminants into the marine environment was inferred.

Description: Evaluation of electromagnetic fields, which is caused by the lightning channel, is an appealing topic in order to consider the indirect effects of lightning on the power lines. In most computations of lightning electromagnetic fields, the return stroke channel is assumed to be a straight and a vertical channel. However, in reality, the lightning channel is most often inclined and has some tortuosity on scales. This paper provides general expressions for the electric field and the magnetic flux density, at any point, that are radiated from an inclined lightning channel. These general expressions are based on the Maxwell’s equations. The proposed equations can estimate the components of the electric field and the magnetic flux density directly at any observation point and for any kind of lightning channel (vertical or inclined). Also, by using the suggested general expressions, the electromagnetic fields can be computed in close, medium and far ranges. The proposed expressions support the notion of the vertical lightning channel by assuming the channel angle with respect to Z-axis equals zero. In this paper, the analysis of the suggested expressions for the electric field and the magnetic flux density that radiated from an inclined lightning channel as well as their verifications by comparing their results with the results of the others is achieved. Also, these suggested expressions are used to investigate the effect of channel geometry, number of the segments to which the channel is sub-divided, position of the observation point with respect to each segment of the channel, and each segment orientations (defined with the azimuth angle ϕ ) and inclination angle θ on the electromagnetic field distributions.

Description: Oceans cover more than 70 % of the Earth’s surface, and water waves are considered as unlimited sources of renewable energy. The use of fossil fuels may cause undesired challenges such as global warming and climate change in the nature. Advantages of renewable energy include low operational cost, environment friendliness, simple maintenance procedures, and non-polluting nature. In this study, an oscillating water column (OWC) system close to the onshore was investigated in water level for wave parameters which consist of different wave heights and wave periods. Efficient energy transformation is achieved by using air turbines. In this study, 20 experimental sets were carried out by a piston-type wave maker. The experimental results showed that the chamber geometry of the OWC, water depth, and wave parameters are most important factors in terms of achieving maximum wave power for energy harvesting.

Description: In this paper, free vibration analysis of a rotating Mori–Tanaka-based functionally graded (FG) beam is investigated based on Timoshenko beam theory. The physical neutral axis position for the mentioned FG beam is determined. By using a semi-analytical differential transformation method (DTM), the governing differential equations are transformed into recurrence relations and the boundary conditions are converted to algebraic equations. The material properties of the rotating FG beam are supposed to vary across the thickness direction based on Mori–Tanaka micromechanics model. In the classical beam theory, the effects of transverse shear deformation and rotary inertia are not taken into consideration, while the Timoshenko beam model takes these effects into account. It is demonstrated that the DTM has high precision and computational efficiency in the vibration analysis of rotating FG beams. The good agreement between the results of this article and those available in the literature validated the presented approach. The detailed mathematical derivations are presented, and numerical investigations are performed, while the emphasis is placed on investigating the effect of functionally graded microstructure, mode number, slenderness ratios, rotational speed and hub radius and boundary conditions on the normalized natural frequencies of the rotating FG beam in detail. It is explicitly shown that the vibration behavior of a rotating FG beam is significantly influenced by these effects.

Description: Radon concentrations and effective radium contents were measured using CR-39 solid-state nuclear track detectors. In this study, 27 local and imported phosphate fertilizer samples (liquid and solid) were collected from markets in eastern Saudi Arabia. The radon concentrations were found to vary from 3.23 ± 1.2 to 1547 ± 162 Bq m −3 . The radon exhalation rates and effective radium contents ranged from 1.77 ± 0.7 to 848 ± 89 mBq m −2 h −1 and from 3.53 ± 1.1 to 2246 ± 236 Bq m −3 , respectively. The highest annual effective dose was from a local fertilizer sample (39 ± 9.8 mSv y −1 ); this value was higher than the world allowed dose. Therefore, these fertilizers can be a significant source of radiological hazards to human health. Strong correlations were found between the radon concentrations, exhalation rates and annual effective doses from the local and imported phosphate fertilizers. The radon concentrations in all fertilizer samples were compared with the recommended value from ICRP (200 Bq m −3 ).

Description: Microwave heating has been applied to improve the drying efficiency and reduce energy consumption in the dehydration of hydrometallurgy mud. Experiences of microwave drying of hydrometallurgy mud are optimized using response surface methodology. The effects of each factor and their interaction on the dehydration ratio are investigated, and a second-order polynomial model for dehydration ratio is established. The optimized microwave drying conditions are as follows: sample mass 28.89g, microwave power 630.56W and drying time 3.17min. The predicted dehydration ratio of hydrometallurgy mud is 99.62%, which is closed to the averaged experimental value of 99.36% under the optimal conditions, indicating that regressive equation is fit for the dehydration ratio perfectly. Particle analysis suggests that the size distribution of materials using microwave heating is more even than that in an oven. The technology has great significance to shorten drying time and to reduce the energy loss for the industrial application.

Description: Recently, a shift from CMOS lithography to nanoelectronics chemical assembly has been under investigation. Nanoscale components are assembled into arrays of low-power and high-density nanofabrics, which can be integrated with conventional CMOS systems. The inability to achieve inexpensive defect-free mass manufacturing of nanoelectronics is the largest impediment of their adoption. Limited nanowire lengths and defect-prone nanodevices pose significant challenges for design automation tools. In this work, we propose a design phase for cell mapping and reconfiguration in novel hybrid CMOS/nanoelectronics architecture called CMOL. Reconfiguration consists of finding new suitable physical location for each gate such that the circuit becomes defect free. The novelty of this work is to engineer non-deterministic iterative search heuristics, namely simulated evolution (SimE) and Tabu search (TS), to find cell assignment around defective nano-components. Circuits of various sizes from ISCAS’89 benchmarks are used to evaluate the designed heuristics. Results show that SimE and TS yield successful reconfigurations in reasonable computation time when nanodevice defect rate is as high as 50 % and nanowire cut rate up to 70 %.

Description: Ground granulated blast furnace slag (GGBS)-based geopolymer is an excellent binder that attains high strength by curing at room temperature. Fly ash-based geopolymer binder, on the other hand, attains high strength when heated in particular temperature range. Although literatures on GGBS- and fly ash-based geopolymer are plenty, reported literatures on soil–geopolymer system are limited. An attempt has therefore been made in the present paper to investigate soil–geopolymer incorporating slag, fly ash and blending of slag and fly ash as source materials. It was observed that unconfined compressive strength of soil–geopolymer system increases with the source material content. Molar concentration of alkali activator, alkali-to-source material ratio and percent content of source material altogether affect the unconfined compressive strength of stabilized soil that is not straightforward. Na/Al and Si/Al ratios of the geopolymer mix ultimately govern the strength of stabilized soil. It was also observed that slag content is the most dominating factor affecting unconfined compressive strength rather than Na/Al ratio in case blending of GGBS and fly ash.

Description: The Kingdom of Saudi Arabia is one of the leading countries in date fruit farming, and by-products from date palm trees can be used for several important applications, including pollution control. This study successfully employed date palm pit-based granular activated carbon (GAC) to adsorb gas-phase benzene under dynamic flow conditions. The percent carbon content (w/w) for raw date palm pits and produced GAC samples was found to be 47 and 82 %, respectively. Furthermore, the specific surface area (SSA BET ) of the produced GAC was 822 m 2 /g, and the t-Plot micropore area and t-Plot external surface area were 734.99 and 87.26 m 2 /g, respectively. The BJH graph for the pore size distribution also indicated a mesoporous structure. The use of date palm pit-based GAC for gas-phase benzene adsorption under dynamic continuous-flow conditions showed high efficiency with breakthrough points for different systems ranging from several hours to several days. The role of surface functional groups and their interactions with the benzene rings during the adsorption process were also explored, and surface oxygen-based groups may initiate an electron donor–acceptor mechanism with the benzene’s aromatic ring \({{\boldsymbol{\pi}}}\) electrons. The findings confirmed that GAC produced from date palm pits can be successfully used for gas-phase benzene adsorption under various conditions. It is hoped that countries with large-scale date fruit farming, such as the Kingdom of Saudi Arabia, will be able to utilize this rich resource for environmental applications.

Description: The objective of this study is to investigate the effect of austenizing temperature on high-carbon steels. Two types of steels, i.e., AISI-440C and AISI-A2 were selected in this regard. Specimens of these steels were austenized from 950 to 1250°C and then air-cooled; this resulted in major microstructural changes in the specimens. These microstructural changes altered the electrical resistivity and magnetic permeability of the materials. XRD studies revealed that about 80% austenite formed when the subject steels were heat-treated to 1200°C. Eddy current technique was applied for the assessment of these microstructural changes, which influence the eddy current response in the coil. Similar hardness trend was observed for both steels. The magnitude of eddy current can be used to estimate the volume fraction of phases present in these steels. This study revealed that a good correlation existed between eddy current measurements and microstructural changes in these steels.

Description: The main goal of this paper was to predict the total organic carbon (TOC) from well logs data using the multilayer perceptron (MLP) neural network machine. This can replace the Schmoker’s method in case of discontinuous measurement of the bulk density log. The MLP machine is composed of three layers, an input layer with four neurons corresponding to the Gamma ray, the neutrons porosity, and the slowness of the P and S waves well logs. The output layer is formed with one neuron, which corresponds to the predicted TOC log, and a hidden layer with ten neurons. The MLP machine is trained using the Levenberg–Marquardt algorithm. Data of two horizontal wells drilled in the lower Barnett formation located in USA are used. Comparison between the predicted and calculated TOC log using the Schmoker’s method clearly shows the use of the neural network method to predict the TOC in shale gas reservoirs.

Description: This study investigates the performance characteristics of an industrial robot ABB-IRB1410 for an automated painting process using Taguchi orthogonal array (OA) and gray relational analysis (GRA) and compared with the manual painting method using HVLP gun. The multi-response process is converted into single objective and optimized using GRA. The method established in this study combines both OA and GRA. The experiment is designed using Taguchi’s L9 OA. The foremost objective of this experiment is to identify the control parameters for the improved quality of paint coating measured in terms of thickness variation, surface roughness and film adhesion. In addition to that analysis of variance and regression analysis are carried out to find the influencing parameters on each response variables individually and to build the mathematical model, respectively. Also the GRA result is compared with the optimized value determined by the exhaustive search method.

Description: Direct Blue 199 is used to colour carpets. In this study, adsorbents prepared from maize cob, citrus peel and rice husk (agricultural wastes) were used to study removal of Direct Blue 199 from its aqueous solution and a carpet industry’s effluent. The adsorption equilibrium studies were carried out by varying the adsorbent dosage at a constant temperature of \({28^{\circ}{\rm C}}\) . Adsorption of the dye varied with different adsorbents. Equilibrium adsorption data were correlated using Langmuir isotherms for all the three adsorbents. Kinetic study showed that it took about 2 h for 80–90% removal. Kinetic data for all the systems studied could be correlated satisfactorily by pseudo-second-order rate equation. It is confirmed by statistical t test (paired two samples for means) that the predicted and observed data were not significantly different statistically. The studies indicated that the adsorbents, maize cob, citrus peel and rice husk powders can be used as low-cost alternatives for the dye removal.

Description: A new class of fuzzy inference system is introduced, a probabilistic fuzzy inference system, for the modeling and control problems, one that model and minimize the effects of uncertainties, i.e., existing randomness in many real-world systems. The fusion of two different concepts, degree of truth and probability of truth in a distinctive framework leads to this new concept. This combination is carried out both in fuzzy sets and fuzzy rules, which gives rise to probabilistic fuzzy sets and probabilistic fuzzy rules. Consuming these probabilistic elements, a distinctive probabilistic fuzzy inference system is developed as a fuzzy probabilistic model, which improves the stochastic modeling capability. This probabilistic fuzzy inference system involves fuzzification, inference and output processing. The output processing includes order reduction and defuzzification. This integrated approach accounts for all of the uncertainty like rule uncertainties and measurement uncertainties present in the systems and has led to the design which performs optimally after training. A probabilistic fuzzy inference system is applied for modeling and control of a continuous stirred tank reactor process, which exhibits dynamic nonlinearity and demonstrated its improved performance over the conventional fuzzy inference system.

Description: Experimental and theoretical investigations are carried out to study and compare the effect of using two gasoline blends, namely octane 91 and octane 95, on the performance and exhaust emissions of a modern fuel injection SI engine at different engine speeds and loads. Theoretical combustion model is able to predict the engine performance when compared to the experimental findings. Results show that the engine performances of both fuels are comparable, with marginal differences, under the tested operating conditions, practically for engine speeds less than 3500 rpm. Higher power and less specific fuel consumption are observed when octane 91 fuel is used compared with octane 95 blend. Both blends do not show a tendency of knock occurrence. In general, both fuels show similar trends for CO, CO 2 and NO x concentrations in the exhaust, whereas the unburned hydrocarbons are slightly higher when octane 91 fuel is used. In the higher speed range between 3500 and 5000 rpm, a noticeable decrease in CO 2 concentration, an increase in specific fuel consumption and CO concentration are observed.

Description: Electric vehicles (EVs) as an alternative to the current fossil fuel vehicles represent the most promising green approach to electrification of an important portion of the global transportation sector. This uncertain load brings new challenges to market-oriented demand response programs (DRPs) specifically in the presence of renewable energy resources (RER). Being a special type of load, EVs are highly capable of providing a significant amount of flexible load demand through participating in various types of DRPs, while using their battery storage potentials allows a higher penetration level of intermittent RER in the grid. Therefore, there is a strong need to increase EV owner’s participation in the market by providing attractive financial benefit-based decision-making tools and simplifying the market process to enhance system reliability and reduce price volatility. In this paper, a novel optimal decision-making methodology is proposed which, unlike previous works, utilizes a grid characteristic’s model within a game-theoretical approach, conflicting and capturing economic interests of both players together and evaluates the optimum strategies for a successful market operation in simplest way. This approach can facilitate both EV owners and utilities to derive their robust bidding strategies, in which they can create a simple business case analysis to weigh their benefits of participation in the market. To evaluate the performance, a simulation framework with uncertain load demands and generation has been developed and compared. The results show that the proposed strategy is appropriate for use in real-time automated DRPs.

Description: In many real-life text mining applications such as clustering academic documents, citation matching and author name disambiguation (AND), similar publications are grouped together by exploiting similarity among them. Most of AND approaches, especially unsupervised ones, focus on either proposing new/alternate algorithms and/or using new/alternate sources of information. Researchers from digital library community pay least attention to similarity measures. They try ready-made alternate measures to estimate optimum similarity among publications. These ready-made measures may not provide real picture of similarity among publications. In this work, we propose four similarity measures specially designed for author names, co-authors and short and long text segments. Our proposed measures provide more realistic picture of similarity among publications than previous measures. Our proposed measures can be applied in many real-life scenarios where either name entities (not necessarily human names) or text documents or both are compared in pairwise fashion. We compare our measures with Jaccard coefficient and state-of-the-art cosine measure based on vector space model. Experiments on synthetic and real data show that our proposed measures are more logical and realistic than baseline methods.

Description: Residual strength and damage characterization of glass fiber, basalt fiber and its hybrid reinforced in epoxy laminates were studied under compression after impact loading. It involves the exploitation of certain characteristics of basalt fiber, in order to ascertain basalt as a suitable alternative to glass fiber. Basalt fiber, extracted from basalt stone, is economically feasible over conventional fibers such as glass or carbon and has relative advantages, both physically and chemically. Low-velocity impact tests under impact energy of 2.17 J and compression test were conducted on each set of laminates, and along with that, the non-impacted specimens were also compared. The results obtained from compression after impact test revealed that glass laminate possessed the highest resistance to impact damage, and this particular hybrid configuration did not prove superior over plain glass or basalt in both impact and compression tests. Therefore, for compression after impact scenarios, basalt does not serve as a viable alternative for glass fiber, especially in this hybrid configuration.

Description: A viscoelastic carbon nanotube (CNT) conveying pulsating fluid is presented which is based on Euler–Bernoulli beam theory. Runge–Kutta scheme is chosen in order to illustrate the transverse and longitudinal behavior of structure. The effects of surface stress, magnetic field and nonlocal small-scale theory on motion of structure are expressed in this study. Equilibrium equations of CNT conveying pulsating fluid are obtained using energy method. Galerkin, differential quadrature and Runge–Kutta methods are applied to solve equations of motion. In this paper, the effect of pulsating fluid on longitudinal behavior of CNT and transverse displacement of CNT are presented. The static and dynamic transverse distributed loads and their effects on CNT are expressed. In this study, regions of CNT with chaotic, quasi-periodic and periodic behaviors are presented. Also the effects of various parameters such as distributed loads, surface stress and magnetic field on those regions are demonstrated. The results of this work could be helpful in design and manufacturing of nano-/micromechanical system in advanced medical applications such as drug delivery systems with magnetic field as a parametric controller.

Description: This research article investigates the effects of xanthan gum and aluminium stearate on the rheological and filtration properties of oil-in-water emulsion drilling fluids. In addition, the stability of emulsion drilling fluids was analysed by measuring interfacial properties such as zeta potential, interfacial tension, contact angle and microscopic properties to estimate the effects of xanthan gum and aluminium stearate on the shape and size of emulsion droplets. The rheological and filtration properties were measured using API recommended standard procedures. Xanthan gum worked as viscosity modifier, aluminium stearate worked as filtrate loss-controlling agent, and both additives also worked as perfect stabilizer for the emulsion systems. The steady-state shear stress–shear rate measurement technique was applied to examine the shear thinning (pseudoplastic) behaviour of the emulsion drilling fluids. The fluids followed strong shear thinning (pseudoplastic) behaviour with increasing concentration of diesel oil and xanthan gum which is a desirable parameter for drilling fluids. It was also found that rheological and filtration properties are stable at 80°C temperature. By optimizing the concentrations of the additives in emulsion system, favourable drilling fluids can be developed which may be used for oil and gas well drilling.

Description: The present work is aimed to reduce the compressor load in a domestic air conditioning system, by introducing a shell-and-coil type heat exchanger as an intercooler. The intercooler uses initially a binary mixture of ethylene glycol:water at 30:70 ratio as a shell-side base fluid and later uses nanofluids with Al 2 O 3 nanoparticles of different volume concentrations. The coefficient of performance (COP) of the system was estimated at different shell-side fluid flow rates of 1, 1.5 and 2 LPM. COP was found to increase with the decrease in the refrigerant temperature at the compressor inlet, due to the reduction in the compressor work input. A highest increment in the COP of around 31 % was observed for the base fluid and 49.32 % was observed for the 0.75 % nanofluid with a flow rate of 2 LPM compared with the case without intercooler. An appreciable reduction in power consumption of 12.24 % was also observed.

Description: Some domain-specific modeling languages (DSMLs) use different diagram types but these are not explicitly included in metamodels. The definition of diagram types is an increasing demand for some computer-aided software engineering tools for DSMLs. The current work presents a technique that allows designers to define diagram types of DSMLs with metamodels in a straightforward and tool-supported way. This technique also facilitates the processing of models when some elements appear in several diagrams, by including a single dictionary of all the entities and their relationships. The presented technique is supported with a novel tool called diagram-type editor tool (DTET). DTET receives input from a DSML metamodel and allows designers to define a set of diagram types with a graphical user interface. Then, DTET generates a metamodel with these diagram-type definitions. For the evaluation, 39 testers from five different countries (Spain, Dominican Republic, Colombia, Ecuador and France) experienced the presented approach and other alternatives, measuring the times of definition and the numbers of mistakes. The results show that the presented technique and DTET are faster and less error-prone for the definition of diagram types than the alternatives with statistically significant differences.

Description: The problem of rotating blade vibrations has been recognized as one of the major causes of the system failure in many applications of engineering systems such as turbine blades of turbomachinery in petroleum and airline industries. Having motivated by the successful use of a piezoelectric sensor to capture vibrations of a rotating blade from its root (fixed end), this study aims at controlling the rotating blade vibrations through piezoelectric materials at the root. Vibrations of the rotating blade are sent back to the piezoelectric actuator placed at the bottom of its root via velocity feedback and proportional control schemes in order to act on the rotating blade for vibration attenuation. The case study on a smart rotor system shows the potential of root-embedded piezoelectric materials in controlling rotating blade vibrations at different shaft speeds.

Description: Saline–sodic soil inherently exhibits extreme characteristics which challenge getting it remediated from mixed contaminants. In this study, the feasibility of removal of cadmium (Cd) in saline–sodic clay soil in presence of mixed pollutants was investigated. Fifteen (15) experimental runs, each having residence time of three (3) weeks, were designed and conducted according to Box-Behnken design to evaluate the effects of contaminants initial concentration (20–100 mg/kg), voltage gradient (0.2–1 v/cm) and polarity reversal (12–48 h) on Cd removal efficiency. The Cd removal efficiency fitted experimentally verified quadratic model (prediction error of 18.60 %) with insignificant lack of fit based on 5 % significant level (R 2 = 0.9917 and p 〈 0.05). Statistical analysis of the model’s parameters shows that the effect of the investigated parameters follows the order: voltage gradient 〉 initial contaminant concentration 〉 polarity reversal rate. The optimal conditions considering optimization of all effecting parameters (both factors and responses) were found to be at voltage gradient = 0.47 V/cm; polarity reversal rate = 19.77 h; initial contaminant concentration = 65.44 mg/kg which yielded highest Cd remedial efficiency of 86 % at 22.45 kWhr/m 3 /mg energy expenditure. The study demonstrated the viability of employing integrated-adsorption technology for the removal of Cd from contaminated saline–sodic clays under extreme soil and contamination conditions. It also further underscores the intricacy of obtaining a common optimal remediation conditions for the different pollutants presence in saline–sodic soil contaminated with mixed pollutants.

Description: The effect of multiwall carbon nanotubes (MWCNTs) on the thermal and ablative properties of carbon fiber epoxy matrix composites was investigated. Thermochemical and oxidation reactions were found to dominate the ablation mechanism. Shear forces and high temperatures were produced using oxy-acetylene torch. Three types of composites were investigated: (a) carbon fiber epoxy matrix composites, (b) carbon fiber epoxy matrix composite containing 0.2wt% MWCNTs and (c) carbon fiber epoxy matrix composite containing 0.4wt% MWCNTs. Composites containing 0.2wt% MWCNTs showed 5.4% increase in erosion resistance, while composites containing 0.4wt% MWCNTs showed 9.6% increase in erosion resistance compared with carbon fiber epoxy matrix composites. Thermal conductivity increased with the addition of MWCNTs, i.e., 15 and 52% in composites containing 0.2 and 0.4wt% MWCNTs, respectively. Due to the addition of MWCNTs, the increased thermal conductivity of MWCNT-loaded epoxy matrix affected the ablation behavior of carbon fibers and resulted in gradual thinning of carbon fibers.

Description: Motion representation is a challenging task in human action recognition. To represent motion, most traditional methods usually require certain intermediate processing steps such as actor segmentation, body tracking, and interest point detection, which make these methods sensitive to errors caused by these processing steps. In this paper, motivated by the successful recovery of low-rank matrix using robust principal component analysis (RPCA), we present a novel motion representation method for action recognition by extracting refined low-rank features of RPCA. Compared with the traditional methods, our method does not require the intermediate processing steps mentioned above. Unfortunately, with traditional λ, RPCA is incapable of extracting the discriminative information of motion in action videos, thus we first conduct extensive experiments to determine a feasible parameter λ suitable for action recognition. Then, we perform RPCA with this λ to obtain the low-rank images including the discriminative information of motion. To represent characteristic of the obtained low-rank images, we define two descriptors [i.e., edge distribution histogram (EDH) and accumulated edge distribution histogram (AEDH)] to refine the low-rank images. Finally, a support vector machine is trained to classify human actions represented by EDH or AEDH features. The efficacy of the proposed method is verified on three public datasets, and experimental results have shown the promising results of our method for human action recognition.

Description: The use of biomaterials depends on the high quality of the manufacturing and processing technology. Thus, the goal of this study is to contribute to the field of manufacturing of biomedical devices used in the human body. The forming and machining microtapping process (M3 thread and pitch 0.5 mm) in Ti-6Al-4V alloy was investigated. The design of experiments (DoE) was performed to identify the effects of factors (speed and type of process) on the thrust force, torque, and ultra-microhardness. The biocompatibility of the formed and machined thread surfaces was evaluated through potentiostatic polarization and electrochemical impedance tests. A simulated body fluid was used as the electrolyte. The experimental results showed that the rate of passivation of titanium alloy was highest for machined threads. Furthermore, the low level of speed (2 m/min) presented better surface finish and more complete fill rate of thread profile.

Description: Here we report the synthesis, characterization and photocatalytic studies of cobalt selenide nanoparticles. Synthesized cobalt selenide nanoparticles were characterized by using X-ray diffraction analysis and transmission electron microscopic analysis, which revealed that the nanoparticles are crystalline in nature, circular and having particle size of 20–25 nm in diameter. Furthermore, thermogravimetric behavior (thermogravimetric analysis/differential thermal analysis), optical and photocatalytic activity of the cobalt selenide nanoparticles were also evaluated. Thermogravimetric results revealed that the cobalt and selenide are strongly interacting, which is also supported by the selective area energy dispersive X-ray spectroscopic analysis. We have applied the synthesized cobalt selenide nanoparticles for an efficient photocatalysis of rhodamine B under ultraviolet light illumination, which resulted in the production of chemically reactive molecules containing oxygen by the cobalt selenide nanoparticles. Based upon the present results, we conclude that the synthesized cobalt selenide nanoparticles are environmentally significant. Moreover, the energy band gap as computed by the Tauc formula was observed to be in the range of \({{E}_{\rm g}=1.8}\) eV.

Description: A significant breakthrough in concrete technology was achieved using fibers to reinforce concrete. Various researchers have reported that fiber reinforcement can alter the brittleness of concrete. The efficiency of fiber reinforcement is based on the fiber–matrix interactions. The understanding of these interactions is a challenging engineering problem, where the frictional bond governs and the physical/chemical bond plays a minor role. This problem is extremely sophisticated because of the following nonlinear interactions: interfacial debonding, plastic material deformations, mechanical bond deformations, and frictional sliding. This paper reports a comprehensive and up-to-date literature review on the fiber–matrix interactions, and physical and theoretical modeling of the fiber–matrix interactions is reported in detail. In addition, the most important conclusions of the parametric studies of the fiber–matrix interfacial bond are summarized. The information of the pullout test standardization to assess the fiber–matrix behavior of a fiber-reinforced concrete is reviewed. The current research in the area of fiber–matrix interactions of fiber-reinforced concrete are discussed.

Description: In recent years, a lot of data hiding algorithms have been proposed in the literature. Providing high payload capacity, high visual quality, and robustness is the main aim of data hiding algorithms. However, high visual quality and high payload capacity are inversely proportional. For this reason, we used a probabilistic method. Probabilistic method is one of the soft computing methods. In this paper, a new data hiding algorithm based on probabilistic XOR secret sharing (PXORSS) in lifting wavelet transform (LWT) domain is proposed for providing high capacity and high visual quality. Previous studies have used cover images as RGB images or multiple grayscale images. LWT is proposed to use secret-sharing-based data hiding algorithms with a single grayscale cover image. In the proposed method, we used low–high (LH), high–low (HL), and high–high (HH) high-pass filter bands as cover images, and the secret data are divided into three secret shares by using PXORSS scheme. The least distorted pieces of probabilities are embedded into the high-pass filter bands as the secret share of the host image. We obtained high capacity and high visual quality in LWT domain by using the proposed method.

Description: The problem of debonding failure is a fundamental issue in concrete structures that are externally strengthened with adhesively glued plates. Many standards and studies recommend using single-lap pull-out tests to measure the ultimate force that causes debonding failure. The pull-out test also allows defining and calibrating interface bond-slip relationships between concrete and the bonded plates to obtain the maximum interfacial bond strength. The aim of this research was to enhance bond strength in the presence of embedded shear connectors, which were fabricated at concrete–adhesive interface level to delay debonding of the externally bonded strips from the concrete surface. A new rational model was also proposed to predict the bond strength of adhesively glued plates-to-concrete joints in the presence of connectors. In the experimental programme, 60 concrete prisms with adhesive and steel bar connectors were fabricated. The specimens were divided into two main series of concrete prisms bonded with steel plates and CFRP strips using the new connectors. Different diameters of connectors were used with and without adhesive on the surfaces of concrete prisms to bond the strips for investigating the capacity of the new embedded connectors. The experimental results showed that the interfacial bond strength increased remarkably when these connectors were used. Moreover, it was found that increasing the connector’s diameter has a great effect on increasing the bond strength and uniformly distributes the interfacial shear stresses, leading to the minimisation of premature debonding failure of bonded plates. The results exhibited that the steel connectors are more effective at increasing the shear bond strength for all specimens adhesively glued with both CFRP strips and steel plates. Finally, the proposed bond strength model was satisfactorily verified through the experimental investigations.

Description: The purpose of this paper was to study the local scour formation due to an inclined circular bridge pier. The experiments for two cases of inclined and vertical piers under clear-water condition with four different flow conditions have been performed. The experiments were conducted in the hydraulic laboratory of Tarbiat Modares University in a rectangular channel. Also, for better interpretation of the observed changes, the longitudinal component values of the velocity in a vertical plain with definite distance located downstream of the vertical and inclined piers were recorded using a velocimeter. The results show that although the scour hole shape and its ridge is changed with the inclination angle of pier, the maximum scour depth in a laterally inclined pier is almost equal to that of a vertical pier and the location of the maximum scour depth in vertical pier has transferred from the 0° area to the approximately 30° area in inclined pier state.

Description: Building collapse incidents have become quite common in different parts of the world. Even though several reasons and causes have been identified for these incidents, their impact on the environment has not reduced. If proper maintenance and repair works are carried out in time, the risks may be minimized. In this study, a geospatial approach has been developed to identify the hazardous buildings with basic structural properties for municipal areas. Various thematic layers are generated on GIS platform, such as types of building, material of construction, structural defects, age of the building, and number of floors from both satellite imagery and field visit using GPS. Methodology adopted was weighted overlay approach through multi-criteria decision analysis (MCDA). Four models were developed to identify hazardous building zonation (HBZ) using expert opinions from various civil engineers. The results have been validated by conducting field tests using nondestructive testing, i.e, rebound hammer test and ultrasonic pulse velocity (UPV) test on various hazardous buildings. Hence, using geospatial tools (remote sensing, GIS, and GPS), local government and decision makers such as civil engineers and planners can identify the risk involved buildings in an area, so that suitable measures can be adopted to reduce the probable chance of failure or any damage to those buildings.

Description: The present work is an experimental and a numerical investigation of the turbulent fluid flow and heat transfer in an annular channel between two concentric cylinders with heated stationary outer cylinder (constant heat flux) and adiabatic rotating inner cylinder. Numerically, the governing equations are discretized in a finite volume fashion using a non-staggered (collocated) arrangement of the variables. The solutions were obtained using the SIMPLE algorithm with upwind scheme. A computer program in FORTRAN 90 was build to solve a set of partial differential equations that govern the fluid flow and heat transfer in annular channels. The experimental results are obtained for an inlet air velocity range of 2–6 m/s, for a wall heat flux range of 600–1200 W/m 2 and a rotational speed range of inner cylinder of 0–1500 rpm with a gap width of 1.5 cm. Finally, the relationships between the average Nusselt number and the effective Reynolds number for experimental and numerical results were proposed and compared with those in the existing literature.

Description: Integrating vehicular ad hoc network and 3G networks helps to use suitable characteristics of networks in exchanging information. In the proposed integrated network, mobile gateways are used as gateways between two networks. Selecting optimum network and gateway is the key point in the phase of vertical handover decision-making process. The multi-criteria algorithms provide simultaneous attention to several important aspects of vertical handover process which improves system efficiency in accordance with the objectives of the defined heterogeneous network. In the proposed method, analytic hierarchy process method is used to determine the weights of the criteria and the modified VIKOR (from Serbian: VIseKriterijumska Optimizacija i Kompromisno Resenje that means: Multi-criteria Optimization and Compromise Solution, with pronunciation: VIKOR) method is used for decision making in heterogeneous networks. The simulation results show that the proposed algorithm is suitable for selecting the optimum gateway in a heterogeneous wireless networks and it improves the average number of vertical handovers, average delay, and throughput in sparse vehicular networks.

Description: Given a set of k -dimensional objects, the skyline-CL query returns all clusters over skyline objects according to their cardinalities. A naïve solution to this problem can be implemented in two phases: (1) using existing skyline query algorithms to obtain all skyline objects and (2) utilizing the DBSCAN algorithm to cluster these skyline objects. However, it is extremely inefficient in real applications because phases 1 and 2 are all CPU-sensitive. Motivated by the above facts, in this paper, we present Algorithm for Efficient Processing of the Skyline-CL Query (AEPSQ), an efficient sound and complete algorithm for returning all skyline clusters. During the process of obtaining skyline objects, the AEPSQ algorithm organizes these objects as a novel k -ary tree SI ( k ) -Tree which is first proposed in our paper, and employs several interesting properties of SI ( k ) -Tree to produce skyline clusters fast. Furthermore, we present detailed theoretical analyses and extensive experiments that demonstrate our algorithm is both efficient and effective.

Description: In this paper, the numerical investigation of double-diffusive mixed convection with magnetohydrodynamic flow in an enclosed cavity is presented. The uniform temperature and concentration are imposed along the vertical walls and the horizontal walls which are considered as insulated. The flow behaviour is analysed for two different conditions. In first case, the top wall moves towards left at a constant velocity ( U o ), while the other walls remain stationary. In the second case, the top wall moves towards right with constant velocity ( U o ), while the other walls remain stationary. The convective flux in the transport equations is discretized using finite volume technique with third-order deferred quadratic upwind interpolation for convection kinematics scheme at the inner nodes and the second-order central difference scheme at the outer nodes. The pressure and velocity terms are coupled by SIMPLE algorithm. The present numerical simulation is compared with the reported literature and is found to be in good agreement. The Hartmann number (1 ≤ Ha  ≤ 25), Lewis number (1 ≤ Le  ≤ 50) and aspect ratio (1 ≤ A  ≤ 2) are varied over a wide range to analyse the non-dimensional horizontal ( U ) and vertical velocities ( V ), stream line contours, temperature and concentration gradients. The present analysis is carried out at constant Buoyancy ratio ( N  = 1) and Prandtl ( Pr  = 0.7), Richardson ( Ri  = 1.0), Darcy ( Da  = 1.0) and Reynolds ( Re  = 100) numbers. The effect of Ha , Le and A on the average Nusselt ( Nu ) and Sherwood ( Sh ) numbers is also presented.

Description: Marine actinobacteria have been considered as a potential source of bioactive compounds holding a prominent position as targets in screening programs due to their diversity and their proven ability to produce novel metabolites and other molecules of pharmaceutical importance. In this regard, an attempt was made to study the diversity of actinobacteria and its ability to synthesize silver nanoparticles in Ramanathapuram and Thoothukudi districts of Tamil Nadu. A total of 1143 actinobacteria were isolated, out of which 49 were morphologically distinct based on the spore color, mycelia formation and pigment production. Themorphologically distinct isolates were characterized and identified using light microscope as Streptomyces sp. (16), Nocardiopsis sp. (8), Kitasatosporia sp. (7), Actinopolyspora sp. (2), Thermoactinomyces sp. (5), Actinomadura sp. (4) Kibdelosporangium sp. (3), Saccharopolyspora sp. (3) and Thermomonospora sp. (1). The correlation coefficient analysis between the isolates and the physicochemical parameters of the soil revealed positive correlation with nitrogen. Silver nanoparticles production by the green chemistry approach was investigated using the isolated marine actinobacteria which showed that 25 isolates out of 49, synthesized silver nanoparticles.