ALBERT

Description: 〈h3〉Abstract〈/h3〉 〈p〉Eco-friendly poly(butylenes succinate) (PBS)/bamboo carbon lubricant composites were designed and prepared by hot pressing. The hardness and wear properties of the designed PBS composites were studied. The results showed that the hardness of PBS composite containing 50% of the bamboo carbon lubricant increased by more than 150%. The composite material with 50% bamboo carbon lubricant had the lowest wear rate, which was up to 72% lower than that of pure PBS. The wear of neat PBS was harsh with severe cut and even partly melted points appearing on the worn surface. The wear modes of PBS bamboo carbon composite were abrasive wear and fatigue wear. While the worn surface of PBS bamboo carbon lubricant composite was with slight exfoliation, its wear mode was slight adhesive wear. It is concluded that the addition of bamboo carbon lubricant can broaden the application range of eco-friendly polymer of PBS in the engineering field of anti-wear requirements. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In the present work, dynamical aspects of boundary layer flow of hydromagnetic fluid (suspended with microorganisms) are investigated near the stagnation region over a stretchable heated permeable sheet. Viscosity is taken as a linear function of temperature where the flow field accommodates diffusion processes due to temperature and concentration gradients (Soret/Dufour numbers). A system of partial differential equations is set up for the mathematical description of the related bio-physical phenomenon. Unit free conversions and analysis of symmetry are implemented to obtain nonlinear dimensional free differential equations setup which can be solved numerically via the Runge–Kutta–Fehlberg scheme. Results in the form of pictorial and tabulation representation reveal that velocity profile increases when viscosity is a function of temperature difference, but the velocity profile influences the fluid temperature in the opposite direction.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This article focuses on an experimental analysis of the performance of a mobile manipulator (MM) executing generalized point-to-point tasks. This leads to surpass constraints, depending on the mechanical structure of the robot, on the environment and on the task to be performed. The robotic system is made up of a robotic arm mounted on wheeled mobile robot. Polynomial trajectory planning method is applied to generate trajectories, assigned to a real robot. The experimentations deal with motion coordination, control and task execution problems. Different ways to execute generated trajectories on a real MM (RobuTER/ULM) are tested, and several parameters influencing the movement of the system are examined. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Software testing is one of the most labor-intensive and crucial phases of the software development life cycle. It accounts for about 50–60% of the total cost of a project and requires a substantial amount of effort to ensure that the quality of the software is not compromised. Hence, optimizing the process of software testing has been of paramount importance in the IT industry. In recent times, there has been a significant shift toward software test automation to ensure the quality of the software while minimizing the cost and effort. This study proposes a statistical model analyzing the various factors that affect the testing cost, quality and effort by studying the behavioral pattern of professionals employed in the field of testing. The paper studies the factors, project duration, Software Complexity (SC), testing tools and automated test suite generation, while contrasting it with the overall software test automation, with the aim of finding a measure of how much automation affects the cost, quality and effort in practice. The results indicated that automation accounted for a variation of about 25% in each of the factors: cost, quality and effort much more than factors such as project duration, SC and testing tool . Further, the analysis indicated that the effect of SC on cost and effort was extremely low. This suggests that automation improved the quality while reducing the cost and effort irrespective of the complexity of the software being developed. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Software maintenance is an important software quality attribute. Many factors affect software maintenance, one of them being code cloning. Code clones are segments of code that are very similar. Software stability tends to measure the unchanged code elements. The objective of this paper is to find whether stability metrics can be used as an indicator of code structural similarity. I perform an empirical study to find the relationship between code similarity and stability at the class level. I also conduct clustering to classify stability and similarity metrics into different related groups. Finally, I perform principal component analysis to determine which class stability metrics have the strongest relationship with class similarity. In addition, I built a prediction model to predict class similarity using class stability metrics. The results show that the four investigated stability metrics have a significant relationship with similarity; however, the class stability metric (CSM) has the strongest correlation with code similarity. The clustering results also reveal that classes with high stability tend to have high similarity. In addition, I found that the CSM and class instability metric (CII) can both reveal 74.023% of class similarity. I conclude that stability metrics can be used as a good indicator of class similarity.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The looming threat of fossil fuel depletion coupled with its disastrous environmental effects has compelled researchers to look into alternative sources of energy that can provide two-way solution such as sustainability and environment protection. Biodiesel which is renewable in nature has emerged as a potential alternate to diesel that can be used in unmodified or little modified diesel engine. Biodiesel is commonly prepared by two-step esterification–transesterification chemical reactions. Biodiesel-fuelled engines are not as efficient as diesel-fuelled engines. Therefore, diesel engine systems must be modified suitably to get the desired power, efficiency with reduced fuel consumption and exhaust emissions to meet the customers’ requirements and strict emissions norms set by the legislations. To cater the above said demands, current research is an effort to make an efficient biodiesel engine with lower emissions by suitably modifying the piston that augments turbulence. The induced turbulence produced by modified piston makes a better quality of air–fuel mixture which in turn improved thermal efficiency and BSFC by 1.46% and 5%, respectively. The HC emissions were reduced by 6.7%, while CO reduced slightly. Expectedly, the formation of NOx was found to be increased from 5 to 7.4%.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Leachate is a very hazardous liquid, and it is considered as one of the major concerns regarding landfills. Landfill leachate is the result of water penetration from solid waste and oxidation of waste and parcels. The undeveloped landfills allow the leachate to cross easily through the soil. This can affect the soil engineering properties such as shear strength, soil compressibility and chemical properties (absorption and retention of heavy metals). This research has investigated the influence of the leachate resulted from municipal solid waste in Ardabil with different percentages and densities on the parameters of shear strength and compressibility of the soil around the site. Also, a test, which is called leachate column test, was carried out to study the environmental properties of the soil (the rate of pollutant absorption and pollutants transmission). The results indicate that with increasing leachate percentage, the internal friction angle decreases. Moreover, soil cohesion is significantly reduced and the compressibility results indicate that soil compressibility will also increase. Increasing the concentration of leachate reduces the cohesion and increases the internal friction angle as well as the compressibility, and changes the volumetric pressure of the soil. Also, the results of leachate test, which shows the rate of pollutants absorption and transmission in the sample placed in the chamber, indicate that the concentration of nickel and zing goes up by increasing the volume of the passing leachate.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉 Superalloys are generally considered to be difficult to machinability. In recent attempts to facilitate their machinability, minimum quantity lubrication (MQL) has been used due to its positive influence on cutting tool life, the environment and human health. This study focused on the tool life, wear behavior and surface roughness in the milling of nickel-based superalloy Waspaloy. Uncoated carbide tools, PVD (TiAlN)-coated tools and CVD (TiCN + Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 + TiN)-coated tools were used. Experiments were performed with different cooling methods which included dry, wet and MQL. SEM and EDX were used for tool wear behavior and mechanism analyses. A portable measuring instrument and a 3D optical profilometer were employed for surface roughness analyses. Results obtained from the tests showed that during the milling of the Waspaloy, adhesion and abrasion were effective wear mechanisms for the cutting tools. The main wear behaviors were flank wear, crater wear and BUE (built up edge). In addition to these results, reduction in the tool wear, the wet machining and machining with the MQL system provided improvement at the rates of 37.54% and 29.01%, respectively, when compared to the dry machining. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In the present paper, the potential of the progressive collapse of a reinforced concrete frame of a seven-storey building was evaluated by comparing the capacity curve and the M–N diagram of the beams. The advantage of this approach is that it captures the exact resistance mechanisms occurring during the progressive collapse of the structure such as flexural action, compressive arch action and catenary action. Furthermore, the overlapping of the capacity curves and the M–N diagram were proved to be an efficient tool to optimize the design of the resistance of structures to collapse. The modelling technique based on the Applied Element Method was validated by an experimental test. Consequently, numerical studies were performed according to General Services Administration guidelines using different scenarios implying the removal of one or two adjacent columns from the ground level. Additionally, the slabs were considered in the structural analysis and flexural action was identified as the main mechanism of action against total structural failure. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this paper, the distribution static compensator model based on the bond graph (BG) domain is presented. The methodology is applied to reactive power compensation in distribution systems where a traditional phase lock loop for sensing the AC grid frequency is not needed. The control law is developed using the inverse BG model, which is extracted using the bi-causality concept. In this way, it is possible to perform the distribution system analysis completely in the BG domain. This means that the graphical model is inverted by obtaining the open-loop control law structure, and then the close loop is formulated. The balanced and unbalance conditions are analyzed, generating a control structure that is robust and efficient. The efficacy of the proposed methodology is shown through: partial and complete system simulations in MATLAB/Simulink〈sup〉®〈/sup〉 (MATLAB r2015b, Natick, Massachusetts, 01760, USA), as well as experimental laboratory tests. Such tests use: the rapid control prototyping concept and the real-time simulator Opal-RT Technologies〈sup〉®〈/sup〉 (Montreal, QC, Canada). 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Brain tumor is considered as a fatal disease with low survival rate and has the highest cost of care per patient. This article proposes a computer-assisted system for the recognition of brain tumor image through magnetic resonance imaging based on the monogenic signal analysis. From different monogenic components, textural descriptors are obtained using completed local binary pattern and gray-level co-occurrence matrix. In the pre-processing step, various filtering for noise removal and contrast enhancement techniques are implemented. Local phase, energy and orientation components originated from the monogenic signal analysis method are used for textural feature extraction. Fisher score-based filter approach for feature selection is then employed to derive the discriminating feature set. Finally, the acquired optimal feature set is classified using the support vector machine classifier. Two benchmark MR image datasets, e-health laboratory and Harvard medical laboratory, have been used to validate the system performance. Overall detection accuracy obtained was above 99%. The experimental results demonstrate the effectiveness of the proposed approach and the potential to assist the medical experts in enhancing the detection rate. Furthermore, the presented approach delivers superior performance in brain tumor image recognition as compared to existing techniques.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Erasure codes, in the recent past, have emerged as an alternative to data replication-based systems for storing big data. Efficient choice of code and data nodes from the numerous available storage nodes is the key to the performance of any storage system. This paper presents the Storage Node Allocation Problem for selecting the suitable set of nodes for holding data and code blocks by representing the storage systems as a complete bipartite graph. Additionally, the paper formally proves that the problem is NP-hard and proposes approximate solutions using greedy, ant colony optimization and clustering-based methods. The solutions accomplish efficient choice of storage nodes by utilizing parameters like bandwidth availability, distance between the nodes, computational load and disk space availability.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Gliomas are the most infiltrative and life-threatening brain tumors with exceptionally quick development. Gliomas segmentation using computer-aided diagnosis is a challenging task, due to irregular shape and diffused boundaries of tumor with the surrounding area. Magnetic resonance imaging (MRI) is the most widely used method for imaging structures of interest in human brain. In this study, a deep learning-based method that uses different modalities of MRI is presented for the segmentation of brain tumor. The proposed hybrid convolutional neural network architecture uses patch-based approach and takes both local and contextual information into account, while predicting output label. The proposed network deals with over-fitting problem by utilizing dropout regularizer alongside batch normalization, whereas data imbalance problem is dealt with by using two-phase training procedure. The proposed method contains a preprocessing step, in which images are normalized and bias field corrected, a feed-forward pass through a CNN and a post-processing step, which is used to remove small false positives around the skull portion. The proposed method is validated on BRATS 2013 dataset, where it achieves scores of 0.86, 0.86 and 0.91 in terms of dice score, sensitivity and specificity for whole tumor region, improving results compared to the state-of-the-art techniques. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Traditional reamer blade with double-row cutters and middle channel structure frequently encounters the cuttings deposition and balling when reaming the soft and sticky formation which is easy to hydration and collapsing. Balling causes were analyzed from the view of the cuttings’ properties and the hydraulic characteristics of the traditional reamer blade. Based on the analysis results, a new anti-balling reamer blade technology was presented to address this problem. Evaluations on the cutting force and working life of the new blade were conducted by comparison with the pilot polycrystalline diamond compact (PDC) bit. The theoretic working life of the new blade was about twice longer than that of pilot PDC bit. The hydrodynamic analysis results indicated that the disappearing of low-pressure region and turbulence combined with the lower differential pressure of the annulus fluid can significantly prevent the new reamer blade from cuttings deposition and balling.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Solubility parameters of supercritical water and methanol were probed by using molecular dynamics simulation. The computed solubility parameters agree well with the theoretical values for different temperatures and pressures within the supercritical region. The results show that the solubility parameter decreases with increasing temperature and increases with increasing the pressure. The polarity of the system increases at higher temperatures; therefore, the degree of molecular aggregation increases. Raising the pressure of the system reduces the degree of aggregation between molecules and increases the solubility parameter of the system.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The foremost difficulties related to the use of biodiesel in CI engine are lower BTE and insignificant smoke emissions. These difficulties related to using biodiesel can be resolved by inducting gaseous fuels simultaneously along with primary fuel in CI engine. This paper confers the effect of the compression ratio on the engine on the performance, combustion, and emission characteristics of Niger seed (〈em〉Guizotia abyssinica〈/em〉) oil methyl ester blend (B20) with simultaneous injection of hydrogen (gaseous fuel) at different flow rates. The studies were carried out on a variable-compression-ratio single-cylinder 4-stroke CI engine at 1500 rpm with three different compression ratios of 16, 17.5, and 18.5 and at three different hydrogen flow rates of 5 lpm, 10 lpm, and 15 lpm. The injection of hydrogen notably increased the brake thermal efficiency (BTE) with a significant reduction in brake-specific fuel consumption (BSFC). The combustion characteristics cylinder pressure (CP), net heat release rate (NHRR), and rate of pressure rise (RoPR) also increased drastically. Also, the emission of CO, UHC, and smoke opacity were reduced significantly with spike in NOx emissions. The comparable trends were followed at all the three compression ratios, and the CR 18.5 has shown improved results at a flow rate of 15 lpm. At 15 lpm and CR 18.5, the BTE, CP, NHRR, RoPR, and NOx values were increased by 7.3%, 7.68%, 12.36%, 21.08%, and 56.8%, respectively. Further, the BSFC, CO, UHC, and smoke opacity were reduced by 9.15%, 84.95%, 69.9%, and 59.78% respectively.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Fenton-like processes have been widely studied in recent years and are considered promising for organic wastewater treatment. Enhancement of wastewater treatment performance involves the development of economical and environmental aspects of the process. The present work aims to investigate the degradation and mineralization of an organic model compound, namely patent blue V (PBV) in aqueous solution. The process adopted uses the Fenton-like mode enhanced by UV light, using a low amount of reagent at natural pH, which was close to neutral. Some key parameters including UV light, H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉 dosage, catalyst amount and initial dye concentration in the homogeneous Fenton-like processes were discussed. The complete degradation of 10 mg/L of PBV was obtained in 1 h with low reagent concentrations (0.98 mg/L and 39.1 mg/L of Fe〈sup〉3+〈/sup〉 and H〈sub〉2〈/sub〉O〈sub〉2〈/sub〉, respectively) at natural pH (6.4). The mineralization was justified through the determination of sulfates, nitrates and calcium formed during oxidation. The reaction obeys the pseudo-first-order and kinetic constants, namely the apparent rate constant, the half-life time and the catalytic efficiency, strongly depend on the catalyst concentration. The reutilization of the generated sludge in the photo-Fenton-like process was discussed. However, in spite of the decrease in the degradation efficiency, the possibility of recycling the catalyst Fe〈sup〉3+〈/sup〉 as sludge Fe(OH)〈sub〉3〈/sub〉 makes the process photo-Fenton-like, cheaper and environment friendly.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The NiO–YSZ/LSCF–YSZ dual-layer hollow fiber membrane receives increasing attention which is due liable to quick changes in properties during co-extrusion followed by the co-sintering method. The effect of mixed bore liquid of water + ethanol +〈em〉 n〈/em〉-methyl-2-pyrrolidone and co-sintering temperature on physical and chemical characteristics of the obtained membrane was systematically explored in this study. Here, the characterization of the membrane was inspected using scanning electron microscope–energy-dispersive X-ray, three-point bending, mercury porosimetry, X-ray diffraction and nitrogen tightness tests as well as the oxygen permeation test. Results indicated that membrane prepared using 100% water as a bore liquid produced a sandwich structure. On the contrary, by employing 40:10:50% of water/ethanol/NMP as a mixed bore liquid and sintering for 8 h at 1300 °C, an open-channel structure in the microstructure gives a good porosity as tested using mercury porosimetry, mechanical properties and nitrogen permeability with no secondary phases. In addition, the co-sintering effect was examined by increasing temperature to 1400 and 1500 °C. However, an impurity phase of LaZr〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 was formed which is due to the chemical reaction of La and Sr into YSZ structure. Oxygen permeate concentration through the dual-layer membrane was found to be slightly different as compared to the single-layer hollow fiber membrane. The results further suggest that the outer layer should be tighter and thinner to enhance the oxygen ion diffusion.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Intermediate oxides are synthesized by heating fresh lead dioxide obtained from commercial positive plates of lead-acid batteries. These oxides are soaked in sulfuric acid with 1.28 s g under stirring for 1 h. The obtained powders are analyzed using X-ray diffraction and chemical analysis. The samples are discharged with a cathodic current of 1 mA in sulfuric acid with 1.28 s g, and the capacity is determined. It is found that lead dioxide obtained from PbO〈sub〉1.55〈/sub〉 is more active than the fresh sample. It shows an increase in capacity of 17%. This is due to the increase in the quantity of structural water as given by the chemical and thermal analyses.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sand casting is the one of the oldest fabrication techniques, which has a number of important technological challenges with respect to improving productivity and quality of the castings. It is essential for the foundries to reduce or eliminate the casting defects if they need to survive in this highly competitive global market. This review arises from a strong industrial demand for understanding the physical and process parameters to improve the quality and soundness of the sand-cast products. The present article primarily reviews the investigations done by researchers on the usability of locally available silica sands and clays for casting both ferrous and non-ferrous alloys. The paper highlights the application of artificial intelligence techniques in predicting the sand mould quality and further optimizing the casting process parameters. This article also analyses the potentials and feasibility of three-dimensional printing in sand casting process. Further, the role of different additives on sand mould composition and different trace elements or inoculants on mechanical properties and microstructure of sand casting has been discussed. Finally, elaborations have been made about various types of hybrid sand casting processes along with metal matrix composites.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A novel three-dimensional inverse method based on the time-accurate solution of Navier–Stokes equations for axial compressor design is proposed in this work. The main novelty lies in the derivation of an inverse design boundary condition established on the conservation of Riemann invariant in order to directly design the blade surface. Specifically, a dynamic mesh technique is employed to update the grids and reduce the computational costs. In addition, some restrictions are imposed on the blade surface movement in order to avoid unrealistic airfoil profiles and guarantee computational robustness. Two redesign procedures are presented, including shock wave strength restrain for the NASA Rotor 37 stage and integrated controlled diffusion airfoil concept design for the Stage 35. Results indicate that this novel inverse method is effective for detailed axial compressor design.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Spontaneous imbibition and displacement are important mechanisms in water flooding. This paper is aimed to evaluate the performance of water imbibition and injection in tight sandstone oil reservoir. Imbibition tests were first done to assess potential contributions to displacement and oil recovery. Then, a subsequent water injection at constant pressure was conducted in cores with permeability less than 0.1 mD and larger than 0.1 mD to explore the extent to which oil can be displaced and to evaluate fluid flow behavior. Finally, water injection at constant velocity was implemented to simulate displacement under reservoir condition and to analyze flow characters during injection. Results showed that water imbibition enhanced recovery more significant in cores with permeability less than 0.1 mD than that in cores with permeability larger than 0.1 mD. The recovery obtained was 19.2–26.7% and 6.7–7.6%, respectively. The subsequent water injection at constant pressure enhanced recovery further from 6.7–7.6% to 35.2–37.7% in cores with permeability larger than 0.1 mD. However, it did not make sense in cores with permeability less than 0.1 mD. There were a narrow area for oil/water co-flow and a sharp decrease in oil permeability at the initial stage. Meanwhile, the recovery during water injection at constant velocity was 57.7% and 42.9%, respectively. It presented high injection pressure in the upstream, and the quasi-threshold pressure gradient reached 80–200 MPa/m, which was hard to implement in reservoir. The injection pressure increased with the decrease in permeability. It also reveals that dominant channels exist and may lead to early water breakthrough which is negative for recovery enhancement.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A new method of synthesis was developed for the preparation of sorbent basic bismuth nitrate [Bi〈sub〉6〈/sub〉O〈sub〉5〈/sub〉(OH)〈sub〉3〈/sub〉](NO〈sub〉3〈/sub〉)〈sub〉5〈/sub〉·2H〈sub〉2〈/sub〉O (BBN-EtOH). This electrochemical method includes electrodeposition from an acidic Bi(III) solution in 96% ethanol at a constant current density of 150.0 mA cm〈sup〉–2〈/sup〉. Final product was obtained by thermal treatment at 200 °C. Characterization of BBN-EtOH was conducted by employing XRD, FTIR, SEM–EDX as well as BET, and its pI was also determined. The analysis showed that the material obtained is pure [Bi〈sub〉6〈/sub〉O〈sub〉5〈/sub〉(OH)〈sub〉3〈/sub〉](NO〈sub〉3〈/sub〉)〈sub〉5〈/sub〉·2H〈sub〉2〈/sub〉O. Morphologically, it is composed of aggregates which were formed of several smaller particles of various shapes and sizes, some smaller than 100 nm. Electrochemically synthesized sorbent (BBN-EtOH) was used for the removal of the textile dye Reactive Blue 19 (RB19) from deionized water and model solution of river water, and it showed considerably superior sorption performance compared to other inorganic sorbents synthesized by conventional methods reported in the literature. Kinetic study suggests that the sorption process is both under reaction and diffusion control. Equilibrium of the sorption process was attained in several minutes, i.e., the sorption process is very fast. The sorption equilibrium data were well interpreted by the Langmuir, Sips and Brouers–Sotolongo isotherm. The maximum sorption performance was achieved at pH 2.0, and according to the Langmuir isotherm, it is 1344.99 mg g〈sup〉–1〈/sup〉.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, naturally heated clay (NHC) was complexed with synthesized ionic liquid (1-ethyl-3-methyl imidazolium bromide solution (EMIB)) to form NHC/EMIB composite. The effectiveness of NHC/EMIB composite in comparison with naturally heated clay (NHC) as an eco-friendly adsorbent for dephenolation of petroleum effluent was investigated. The adsorbents were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. Batch mode experiments were conducted to ascertain the effect of process variables on adsorption. Removal efficiencies of 81.70% and 91.7% were obtained for NHC and NHC/EMIB composite, respectively, at 25 min, 308 K, pH 4.0 and 150 µm. The linear and nonlinear isotherm data fitted best to the Langmuir model for both adsorbent, while the linear and nonlinear kinetic data fitted best to pseudo-second-order and pseudo-first-order models for both adsorbents. The estimated average thermodynamic parameters (Δ〈em〉G〈/em〉〈sup〉0〈/sup〉 = − 9.653 kJ/mol, Δ〈em〉H〈/em〉〈sup〉0〈/sup〉 = –28.295 kJ/mol and Δ〈em〉S〈/em〉〈sup〉0〈/sup〉 = –46.395 kJ/mol) revealed the feasibility, exothermic nature and spontaneity, respectively, of the studied adsorption system.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this paper, the influence of natural cavities on the propagation of hydraulic fractures is investigated using the phase field method. The deflection behaviour of a fracture during its propagation is firstly verified against published experimental data. Then, a sensitivity analysis on the mechanical behaviour of fracture propagation near a cavity is conducted. The fracture deflection is quantified in terms of the deviation distance and deflection point. The influence of the Young’s modulus ratio between the cavity and rock mass (〈em〉E〈/em〉〈sub〉r〈/sub〉= 〈em〉E〈/em〉〈sub〉cave〈/sub〉/〈em〉E〈/em〉〈sub〉rock〈/sub〉), the differential stress (〈em〉S〈/em〉〈sub〉d〈/sub〉= 〈em〉S〈/em〉〈sub〉〈em〉x〈/em〉〈/sub〉 − 〈em〉S〈/em〉〈sub〉〈em〉y〈/em〉〈/sub〉) and the relative spatial position of the fracture and cavity (〈em〉l〈/em〉〈sub〉r〈/sub〉) on the propagation trajectory are considered. Simulation results show that with the decrease in 〈em〉E〈/em〉〈sub〉r〈/sub〉, crack path deviation becomes more prominent. With the increase in 〈em〉S〈/em〉〈sub〉d〈/sub〉, hydraulic fractures tend to propagate along the direction of maximum horizontal geostress. As 〈em〉l〈/em〉〈sub〉r〈/sub〉 varies, the deflection of the hydraulic fracture can be classified into three regimes: (1) the deflection is negligible; (2) the hydraulic fracture deflects and approaches the natural cavity, but does not connect with it; (3) the hydraulic fracture deflects and connects with the natural cavity. The results could be used as guidance for field design of stimulation scheme in carbonate oil/gas reservoirs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉With the increasing of drilling depth, the working conditions of the drilling engineering are becoming more complicated. When drilling in the complex well structure, there are many new problems or challenges such as low rate of penetration (ROP), serious stick–slip phenomenon, or high risk of downhole tools failure. The most critical factor in solving these new challenges is improving rock breaking efficiency. Considering this, this paper proposed a new oscillator based on the positive displacement motor. Combining with new complex drilling conditions, the new structure was designed. The mathematical models were presented, including the working mechanism of the new design with its structure parameters. Furthermore, the theoretical models of dynamics under new conditions were analyzed, including the new bottom hole assembly. Based on this, we can get the vibration displacement, velocity, and the system vibration spectrum at different drill string positions. Compared with the results of a numerical example, the lab test was carried out. The two important parameters of vibration frequency and impact forces were compared with the theoretical results, which verified the correctness of the theoretical model and the accuracy of the solution method. Moreover, field experiments were also tested to verify the results, and the field experimental data showed that the new design could increase ROP obviously. The method and conclusions of the research can provide a new reference for the new downhole technology of enhancing the ROP or improving the rock breaking efficiency in complex well structure.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Deep saline aquifers are perhaps one of the most ubiquitous sites available for CO〈sub〉2〈/sub〉 sequestration. In this study, a compositional reservoir simulator was used to evaluate the effects of various CO〈sub〉2〈/sub〉 trapping mechanisms in a saline aquifer which includes structural, solubility and mineral trapping. CO〈sub〉2〈/sub〉 was injected at a rate of 4000 m〈sup〉3〈/sup〉/day at the bottom of the aquifer for 50 years. The results indicate that structural trapping dominated for initial 3 years, after which the maximum gas saturation and pressure was reached. During solubility trapping, the gas saturation decreased by more than 70% of the maximum saturation. Mineral trapping decreased saturation further by another 10%. In another approach, the effect of wastewater injection following injection of CO〈sub〉2〈/sub〉 was evaluated. The numerical simulations show reduction in both the amount of mobile CO〈sub〉2〈/sub〉 and its upward migration. Among the different trapping mechanisms, solubility trapping is found to be the most vital one. Multivariate analysis and optimization of the responses, viz. average gas saturation and average pressure rise, were carried out using response surface methodology. Optimized results were obtained for efficient CO〈sub〉2〈/sub〉 sequestration with lesser mobile CO〈sub〉2〈/sub〉 and pressure rise at lower values of injection rate (1000 m〈sup〉3〈/sup〉/day), injection time (50 years), vertical-to-horizontal permeability ratio, 〈em〉K〈/em〉〈sub〉v〈/sub〉/〈em〉K〈/em〉〈sub〉h〈/sub〉 (0.016), and residual gas saturation (0.4).〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This article presents quantitative assessment of drag models based on their effect on hydrodynamics of a circulating fluidized bed (CFB). Three-dimensional full-loop computational fluid dynamics simulation using Euler granular multiphase model is carried out. Six drag models (EMMS, Gibilaro, Gidaspow, Schiller–Naumann, Syamlal–O’Brien and Wen–Yu) were employed, and simulated results of time-averaged solid volume fraction, solid axial velocity and static pressure are compared with the experimental data. Furthermore, a quantitative analysis is carried out using statistical parameters and parity plots. It was concluded that EMMS model is the most suitable model for simulation of a CFB as it is the only model capable of predicting heterogeneity of the bed, and simulation results agree well with the experimental data.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The scratch resistance and wear behavior at relatively high normal loads of binary (TiN, CrN) and ternary (Al〈sub〉0.50〈/sub〉Ti〈sub〉0.50〈/sub〉N, Al〈sub〉0.68〈/sub〉Cr〈sub〉0.32〈/sub〉N) coatings were comparatively investigated. Scratch test results showed that based on the adhesive strength the coatings can be ranked thus: CrN 〉 TiN 〉 Al〈sub〉0.68〈/sub〉Cr〈sub〉0.32〈/sub〉N 〉 Al〈sub〉0.50〈/sub〉Ti〈sub〉0.50〈/sub〉N. The binary coatings were found to possess superior adhesion strength mainly exhibiting a tensile cracking failure mechanism. In contrast, the ternary coatings failed more severely by through-thickness cracking with spallation. The ternary coatings exhibited an average of 68, 67 and 55% improvement in the wear resistance at 15, 20 and 25 N normal loads, respectively, over the binary coatings. Abrasive and oxidation wear were the main wear mechanisms of the binary coatings. The formation of protective tribo-oxide layers is associated with the improved wear resistance behavior of the ternary coatings. High surface roughness due to large amount of surface defects coupled with low plastic deformation resistance and high Al content are reasons for low wear resistance of Al〈sub〉0.68〈/sub〉Cr〈sub〉0.32〈/sub〉N in comparison with Al〈sub〉0.50〈/sub〉Ti〈sub〉0.50〈/sub〉N coating. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study provides new insights into pore-scale displacement events during the simultaneous flow of a low-molecular-weight polymer solution and heavy oil through porous media. Rheological measurements were taken to examine the viscosifying ability of the utilized polymer. The efficiency of the employed solutions in enhancing heavy oil recovery was also investigated using a pore network micromodel. Both macroscopic and microscopic sweep efficiencies were evaluated by analyzing high-resolution pictures continuously captured during the multiphase flow experiments. The rheological measurements revealed that viscosity of the polymer solution is more sensitive to increasing polymer concentration than salinity. Oil recovery experiments disclosed that polymer flooding could yield a recovery factor of about 58% of original oil in-place (OOIP), while the ultimate recovery factor for water flooding is only 35% of OOIP. The macroscopic observations proved that dwindling the formation of viscous fingers during polymer flooding is one of the main responsible factors for the significant improvement of heavy oil recovery. Moreover, the microscopic observations unveiled the noticeable effect of the polymer solution on the enhancement of microscopic sweep efficiency and showed that pulling effects and stripping mechanisms are effective in reducing the saturation of heavy oil at dead ends and pore walls.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Twisted tape inserts were used as swirl generators in the flow through a tube for enhancing heat transfer. Twisted tapes have commonly been applied in many thermal applications used in industry. Several modified twisted tapes have been investigated for improving the thermal performance of heat exchangers. The effects in tubes with modified rectangular-cut twisted tape (RC-TT) inserts with various free-spacing ratios (〈em〉s/w〈/em〉 = 2.0, 2.5, 3.0, 3.5 and 4.0) and edge–width ratios (〈em〉t/W〈/em〉 = 0.1, 0.15, 0.2 and 0.25) on heat transfer and pressure losses are reported. The RC-TT used in this work had a fixed thickness of 1.2 mm, width of 60 mm, length of 2000 mm and twist ratio (〈em〉y/W〈/em〉) of 3.0. Experiments were performed over a range of Reynolds numbers, 10,000 ≤ 〈em〉Re〈/em〉 ≤ 20,000, using air as a test fluid. A tube with a classical/typical twisted tape was also tested for comparison. In all cases, the Nusselt number tended to increase with the Reynolds number, while the friction factor and thermal performance showed the opposite trend. For the rectangular-cut twisted tape inserts, the friction factor and Nusselt number decreased, while thermal performance increased with increasing free-spacing ratios (〈em〉s/w〈/em〉) and edge–width ratios (〈em〉t/W〈/em〉). Furthermore, the maximum thermal performance was achieved at the lowest free-spacing ratio (〈em〉s/w〈/em〉), edge–width ratio (〈em〉t/W〈/em〉) and Reynolds number (〈em〉Re〈/em〉).〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉California bearing ratio (CBR) is an important property used to express the quality and strength of the unbound granular materials and subgrade soils. It is one of the material inputs for the American Association State Highway Transportation Officials 1993 guide, and the Mechanistic Empirical Pavement Design Guide for the structural design of flexible pavements in case of the resilient modulus is not known. CBR is also conducted on the unbound materials for the quality control/quality assurance during construction. Because of its importance, this paper presents an attempt to develop simple and reliable CBR models based on routine material properties such as gradation, Atterberg limits and compaction properties using regression analysis (RA) and artificial neural networks (ANNs). Database of 207 CBR values was collected from the quality control reports prepared at the Highway and Airport Engineering Laboratory, Mansoura University. The collected CBR values were found to range between 26 and 98%. About 80% of the collected data were used for model development, while the remaining 20% were used for model validation in addition to 11 laboratory tested specimens. The developed model by RA and ANNs correlates CBR values with maximum dry density and diameter at 60% passing (D60). The prediction accuracy in terms of coefficient of determination (〈span〉 〈span〉\({R}^{2}\)〈/span〉 〈/span〉) for the developed CBR model by both techniques was excellent, and the validation of the suggested model was satisfactory.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Oscillatory pressure-driven MHD flow in a vertical rotating channel has been explored in the present article. Emphasis has been given to velocity slip effects along with Hall current and periodic thermal boundaries. Casson fluid model has been incorporated to examine viscoplastic effects. Heat transfer analysis has been performed in the presence of thermal radiation. The current problem has been modeled in a rotating frame. Equations are formulated in the Cartesian coordinate system and simplified by means of suitable non-dimensional variables. Furthermore, closed- form exact solutions are derived for velocity and temperature fields. The effects of pertinent parameters are studied through graphs.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The closed-loop steady-state performances of 〈span〉 〈span〉\(2 \times 2\)〈/span〉 〈/span〉 regulatory control structures are evaluated and compared for a side-by-side FCC unit under partial combustion (PC) and complete combustion (CC) mode. Aspen 〈span〉 〈span〉\(\hbox {HYSYS}^{\textregistered }\)〈/span〉 〈/span〉〈em〉CatCracker〈/em〉 module is used for this purpose. Three types of disturbances are selected, namely feed flow rate change, feed temperature change and the variation in air blower discharge temperature. The control structures in which reactor plenum temperature is controlled by catalyst flow rate have exhibited favourable and superior closed-loop steady-state performances. The successful regulation of conversion is seen as the key for preserving the product yields at their design values. The best workable control structures are identified for both PC and CC modes of operation. For the two modes, the control structures in which regenerator temperature is controlled by catalyst flow rate suffer from closed-loop steady-state multiplicity, infeasible set point or unfavourable closed-loop steady-state performance.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The purpose of the present study is to deal with the potential application of jarosite, a waste material produced during the extraction of zinc ore concentrate using the hydro metallurgy operation, in the production of the concrete. The method involves a total of five mixes including the control mix which was prepared by partially replacing the cement by the jarosite varying from 10, 15, 20 and 25%. It was noticed that incorporation of jarosite did not much alter the fresh concrete properties, as it was well within the desired range. The present laboratory investigation results also confirmed that as the percentage of jarosite in the concrete mix was increased, the mechanical properties of the concrete tend to decrease gradually but can be improved further by adding mineral and chemical admixtures. Further, the water absorption properties were also got improved. Other durability properties like acid attack, chlorine resistance and abrasion loss were found to decrease as the percentage of the jarosite in the concrete mix was increased. From the study, it can be concluded that, up to 15% of jarosite can be used as the replacement of the cement in the construction of the highways. Higher percentage of the jarosite can be used for low traffic volume or village roads for the safe disposal and reuse of the industrial waste.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The worldwide increasing demand for environmentally-friendly transportation fuels and the strict regulations by the environmental protection agencies have put a great pressure on crude oil refining and upgrading industry. The main current technology for the desulfurization of crude oil and its fractions is hydrodesulfurization. However, this process is plagued with several drawbacks. The growing pressure on petroleum refining industries to reduce sulfur contents in fuels has made hydrodesulfurization process even more unappealing. Hence, more effective alternatives have been (and are still) sought by petroleum refining industries. Enzymatic desulfurization process has recently emerged as a promising alternative that has the potential to be cost-effective, efficient and environmental-friendly. In enzymatic desulfurization process, enzymes (whether intracellular or extracellular) attack organosulfur components in the crude oil or its fractions and remove sulfur through a series of enzymatic reactions. The process is an energy-saving process, devoid of emission of harmful gases into the atmosphere, and utilizes completely biodegradable catalysts. This article reviews the recent progress in desulfurization of crude oil and its fractions using extracellular and intracellular enzymes. Challenges encountered during enzymatic desulfurization are highlighted, and some potential solutions to tackle the challenges are proposed. Future outlooks into the development of more efficient enzymatic desulfurization processes have been pinpointed.〈/p〉

Description: 〈p〉The online version of the original article can be found under doi.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The effects of 〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}\)〈/span〉 〈/span〉 addition to 〈span〉 〈span〉\(\hbox {CaSO}_{4}\)〈/span〉 〈/span〉 as a composite oxygen carrier, which is a useful material in terms of its combustion and thermal stability, were evaluated in the chemical looping combustion (CLC) of 〈span〉 〈span〉\({\hbox {CH}}_{4}\)〈/span〉 〈/span〉 and coal. The addition of 〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}\)〈/span〉 〈/span〉 to 〈span〉 〈span〉\(\hbox {CaSO}_{4}\)〈/span〉 〈/span〉 was found to enhance the 〈span〉 〈span〉\(\hbox {CO}_{2}\)〈/span〉 〈/span〉 evolution rate and total amount of 〈span〉 〈span〉\(\hbox {CO}_{2}\)〈/span〉 〈/span〉 produced, with the best results, in terms of 〈span〉 〈span〉\(\hbox {CO}_{2}\)〈/span〉 〈/span〉 production and 〈span〉 〈span〉\({\hbox {CH}}_{4}\)〈/span〉 〈/span〉 conversion, obtained with a 20% by weight (wt%) addition of 〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}\)〈/span〉 〈/span〉 to 〈span〉 〈span〉\(\hbox {CaSO}_{4}\)〈/span〉 〈/span〉 (20%〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}/\hbox {CaSO}_{4})\)〈/span〉 〈/span〉. The preliminary study for thermal stability and regeneratability of 20%〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}/\hbox {CaSO}_{4 }\)〈/span〉 〈/span〉 in the CLC of 〈span〉 〈span〉\({\hbox {CH}}_{4}\)〈/span〉 〈/span〉 and coal was established over four and three reduction–oxidation cycles, respectively, while the morphology and solid composition of the fresh and spent oxygen carrier were analyzed by scanning electron microscopy and X-ray diffractometry (XRD), respectively. The formation of 〈span〉 〈span〉\(\hbox {Ca}_{2} \hbox {Fe}_{2}\hbox {O}_{5}\)〈/span〉 〈/span〉 in the reduced 20%〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}/\hbox {CaSO}_{4}\)〈/span〉 〈/span〉, as detected by XRD measurements, appeared to prevent thermal agglomeration. For the CLC of coal, the reaction was optimal at 〈span〉 〈span〉\(950\,^{\circ }\hbox {C}\)〈/span〉 〈/span〉. The results confirm that the 20%〈span〉 〈span〉\(\hbox {Fe}_{2}\hbox {O}_{3}/\hbox {CaSO}_{4}\)〈/span〉 〈/span〉 composite oxygen carrier could potentially be used in the CLC process of both gaseous and solid fuels.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In both the research and industry studies, mixed integer programming (MIP) is often the default method for solving facility layout problems. While MIP models for the single row layout problem have existed since the 1970s, comprehensive computational research has not been performed since then. In this paper, four different MIP models for the single row facility layout problem with simultaneous asymmetric material flow and corridor width (dubbed SRFLP_AC) are developed based on the decision variable paradigm. We present the computational results and discuss the model efficacy in terms of solution quality and computational budget. Moreover, the performance of two disjunctive models, MIP1 and MIP2, with indicator constraints is also analyzed. Finally, we analyze the effect of the symmetry-breaking constraint and different non-overlapping constraints on the most promising model.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The aim of this study was to improve the life and performance of tungsten carbide turning tool inserts coated with TiN/AlN multilayer thin films using physical vapor deposition technique. Quality characteristics of the coating are evaluated using Calo and VDI 3198 tests. Thickness of the coating is found to be 〈span〉 〈span〉\(3.651 \,\upmu \hbox {m}\)〈/span〉 〈/span〉 with adhesion quality of HF1. The performance of coated tool inserts is evaluated using cutting speed (59–118 m/min), feed rate (0.062–0.125 mm/rev) and depth of cut (0.2–0.4 mm) as process parameters in turning MDN431 steel. Experimental investigation has been carried out based on full factorial design, and regression analysis was used to analyze and build the mathematical models for cutting force and surface roughness. Multi-objective optimization of the process parameters has been done with the combination of desirability approach and MOPSO technique. Optimum machining condition for least cutting force and optimum surface roughness is found to be 〈span〉 〈span〉\({V}_{\mathrm{c}} =59\, \hbox {m/min}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\({f}=0.063\,\hbox {mm/rev}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\({a}_{{p}} =0.2\,\hbox {mm}\)〈/span〉 〈/span〉. Cutting force and surface roughness are reduced by 9% in TiN/AlN-coated tools compared with the uncoated tool. To improve the CoD and capability of predictive regression models, ANN modeling has been adopted. ANN trained model and mathematical regression models are used to predict the results and predict the responses, which follow the experimental data with minimum absolute error. The predicted results are validated using ANN and regression analysis found with minimum error, and developed models are adequate for further usage. Tool wear was reduced by 105% in TiN/AlN-coated tools compared with the uncoated tool.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper investigates the performance, combustion and emission characteristics of a direct injection (DI) diesel engine, fueled with alumina (〈span〉 〈span〉\(\hbox {Al}_{2} \hbox {O} _{3})\)〈/span〉 〈/span〉 nanoparticles-dispersed aloe vera diesel blends. The test fuels B10 (90% diesel and 10% aloe vera biodiesel), 〈span〉 〈span〉\(\hbox {B10}+ \hbox {Al}_{2} \hbox {O}_{3}\)〈/span〉 〈/span〉 (90% diesel, 10% aloe vera biodiesel and 30 ppm of 〈span〉 〈span〉\(\hbox {Al}_{2} \hbox {O}_{3}\)〈/span〉 〈/span〉 nanoparticles), B20 (80% diesel and 20% aloe vera biodiesel) and 〈span〉 〈span〉\(\hbox {B20}+ \hbox {Al}_{2} \hbox {O}_{3}\)〈/span〉 〈/span〉 (80% diesel, 20% aloe vera biodiesel and 30 ppm of 〈span〉 〈span〉\(\hbox {Al}_{2} \hbox {O}_{3}\)〈/span〉 〈/span〉 nanoparticles) are prepared separately for each aloe vera diesel blends at a dosage of 30 ppm with an aid of an ultrasonicator. The combustion characteristics such as heat release rate and cylinder pressure are investigated using the data acquisition system, while the engine performance features are examined by brake-specific fuel consumption and brake thermal efficiency. The levels of engine pollutants are analyzed by unburned hydrocarbon (UBHC), carbon monoxide (CO), nitric oxide (NO) and smoke opacity. These investigations disclosed the use of biodiesel blends with 〈span〉 〈span〉\(\hbox {Al}_{2} \hbox {O}_{3}\)〈/span〉 〈/span〉 nanoparticles in DI diesel engine with significant amelioration of combustion characteristic and substantial decrement of CO, NO, smoke, UBHC emissions and brake thermal efficiency by 44%, 47%, 37%, 29% and 3%, when compared with the diesel fuel.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this paper, Hybrid Cascade Forward Neural Network with Elman Neural Network (HECFNN) is employed to classify six benchmark medical data sets, viz. Wisconsin Breast Cancer (WBC), Pima Indian Diabetes (PID), Liver Disorder Disease (LDD), Heart Disease (HD), Thyroid Disease (TD) and Cardiotocography (CTG). Three famous performance metrics in medical applications including accuracy, sensitivity and specificity are computed. The results of HECFNN are analyzed and compared with the well-known Elman Neural Network (ENN) and Cascade Forward Neural Network (CFNN). The experimental outcome shows that the HECFNN results outperform those of the CFNN and ENN. Performance outcome for WBC was 97.94% accuracy (ACC), 98.88% specificity (SPE) and 98.84% sensitivity (SEN), while results of PID were 85.10%, 75.61% and 88.39% for ACC, SPE and SEN, respectively, LDD results were ACC 93.80%, SPE 90.09% and SEN 87.50%, HD prediction for ACC, SPE and SEN were 94.01%, 96.71% and 90.40%, respectively, TD obtained 96.10% for ACC, 96.45% for SPE and 96.66% for SEN and CTG achieved 100.00% for SEN, 99.25% for ACC and 98.00% for SPE. In addition, the obtained accuracy of the HECFNN for every benchmark is also compared with those different methods published in the literature review. The results demonstrate that HECFNN produce higher accuracy compared with other well-known methods. In general, the HECFNN experimental results positively demonstrate that the HECFNN is effective and useful in undertaking medical data classification tasks.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The present study provides a modified approach in determining gas adsorption equilibria based on two-dimensional equations of state (2-D EOS). The proposed model utilizes temperature-dependent parameters in the general form of the 2-D EOS. These parameters were considered similar to other well-known isotherm models, such as Langmuir as specifics function of temperature. The proposed model was examined against various experimental single- and multi-component adsorption isotherm data. In most of the investigated cases, the proposed model reduces the error of predictions compared with temperature-independent two-dimensional equations of state. Moreover, utilizing temperature-dependent two-dimensional equations of state, isosteric heat of adsorption was theoretically obtained and compared with experimental heats of adsorption for different homogeneous and heterogeneous adsorption systems. Applying temperature-dependent parameters within 2-D EOS enables us to describe the heterogeneity of considered adsorption systems quite well. Predicted isosteric heats are in good accordance with the experimental data.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Speed control of conventional low-voltage low-power induction motors (LV-LP-IMs) by two-level voltage source inverter (2LVSI) has some difficulties due to limitations of LV-LP-IMs especially insulation system. Besides, the use of multilevel inverters is not cost-effective either. In this paper, the new topology of reduced-switch-count three-level inverter with only eight switches is proposed for speed controlling of LV-LP IM. Eight-switch inverter is a newly three-level converter, which has the fewer number of switching devices, lower cost, smaller volume compared with the conventional three-level inverters, while it has sufficient switching vectors to speed control of IMs. In this paper, the structure and switching vectors of the eight-switch inverter are analyzed, and the direct torque control method based on the switching table and voltage balancing of the DC input voltage are presented for the LV-LP-IM speed control. Simulation results, considering different work conditions, are presented in order to validate finally the good performance of the proposed method. Moreover, the obtained results are compared with 2LVSI and conventional three-level inverters in different aspects.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This article addresses velocity slip and induced magnetic field effects on heat transfer and nanofluid flow toward a curved stretching sheet. For a comprehensive and realistic analysis most commonly, used fluids such as water and propylene glycol are taken as the base fluids and single- and multi-wall carbon nanotubes (CNTs) are treated as the nanoparticles. Carbon nanotubes are considered due to their unusual characteristics like extraordinary thermal conductivity, viscosity, heat capacity, density, etc., which are significant in nanotechnology, electronics and material sciences. Moreover, heat transfer is discussed in the presence of heat generation and radiative heat flux. The curvilinear coordinates system has opted for mathematical formulation. The governing system of equations is simplified by employing similarity analysis. Computational analysis is performed on a reduced system by means of shooting method in computational software MATLAB. The computed distributions of velocity, induced magnetic field and temperature are examined for pertinent emerging parameters graphically. Furthermore, bar charts are drawn for the skin friction coefficient and Nusselt number. Some of the major findings include: velocity increased with an increase in surface bendiness. Moreover, the increase in velocity was reported to be slightly more in case of MWCNTs. Fluid flow decelerated with an increase in slip velocity. Reciprocal magnetic Prandtl number contributed to decelerating fluid flow. Moreover, magnetic parameter and 〈span〉 〈span〉\(\gamma \)〈/span〉 〈/span〉 played a significant role in increasing fluid velocity. The presence of CNTs contributed to accelerating fluid flow. Furthermore, the temperature was a decreasing function of surface bendiness. Moreover, the maximum temperature was observed in the case of SWCNTs–PG, while the minimum temperature was reported for MWCNTs–〈span〉 〈span〉\({\text {H}}_2{\text {O}}\)〈/span〉 〈/span〉. Temperature rose for rising values of slip parameter. Reciprocal magnetic Prandtl number, heat generation parameter, thermal radiation and CNTs volumetric fraction contributed in up surging fluid temperature. Furthermore, the Nusselt number was an increasing function of 〈span〉 〈span〉\(\phi \)〈/span〉 〈/span〉, 〈span〉 〈span〉\(\beta \)〈/span〉 〈/span〉 and 〈em〉Rd〈/em〉, whereas the contrary results were noted for 〈em〉k〈/em〉, 〈span〉 〈span〉\(\kappa \)〈/span〉 〈/span〉 and 〈em〉N〈/em〉. Moreover, the maximum value of Nusselt number was reported for SWCNTs–〈span〉 〈span〉\({\text {H}}_2{\text {O}}\)〈/span〉 〈/span〉. Also, skin friction increased for rising values of 〈span〉 〈span〉\(\phi \)〈/span〉 〈/span〉, whereas it decreased with an increase in 〈em〉k〈/em〉, 〈span〉 〈span〉\(\kappa \)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(\beta \)〈/span〉 〈/span〉. Furthermore, maximum and minimum skin friction was noted for SWCNTs in case of both base fluids, respectively. The new-fangled results of the present investigation may be valuable in edifying research and in ceramic, plastic and polymer industry.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A new technique was proposed and implemented through an experimental model to improve the absorber tube of a parabolic trough collector, which was connected to a twisted tube and resulted in a heat transfer enhancement. The enhancement increased the capacity of the tube to absorb solar energy by improving the convective transfer between the inner surface of the absorber tubes and the heat transfer fluid. The new design was dependent on overlapped and reverse flow, which was validated through five receiver tube 〈span〉 〈span〉\((R_\mathrm{t})\)〈/span〉 〈/span〉 models, each one consisting of two types of overlapped flows. The first was a flow through inner twisted tubes (single (STT), dual (DTT), and triple (TTT) twisted tubes), with different hydraulic diameters. The second was a reverse flow through an outer round tube, with both concentric tubes joined at one side by a bayonet end cap. For each 〈span〉 〈span〉\(R_\mathrm{t}\)〈/span〉 〈/span〉, the inlet flow from the central or peripheral tubes was assessed. The results showed a remarkable increase in heat transfer enhancement for most STT models and a greater heat transfer in TTT that was overlapped than for a plain tube collector. The enhancement was accompanied by an increase in the pressure difference that was higher for TTT than STT. For each model, the efficiency of the collector and pressure losses was estimated, and the Nusselt number (〈em〉Nu〈/em〉) and an efficiency evaluation criterion were calculated.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Determining the global optima of integer and mixed-integer nonlinear problems is a useful contribution in various engineering applications. Swarm intelligence is a well-known branch of nature-inspired algorithms which tries to determine the solution with the help of intelligent and collective behaviour of social creatures. Grey wolf optimizer (GWO) is one of the recently developed efficient algorithms which are quite popular nowadays. In the present study, first, the GWO is proposed for solving integer and mixed-integer optimization problems, and secondly, an improved version of GWO named IMI-GWO is proposed. The IMI-GWO attempts to alleviate from the major issues of premature convergence and slow convergence of classical GWO. In IMI-GWO, the opposition-based learning maintains the diversity and the chaotic search locally exploits the regions around the best solutions. To evaluate the performance of IMI-GWO, a set of 16 integer and mixed-integer problems and two engineering application problems, namely gear train and pressure vessel design problems, have been considered. The performance of the IMI-GWO is compared with other algorithms which are applied to solve these problems in the literature and with some recent algorithms. The comparison illustrates the better performance of the proposed algorithm.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The fifth-generation (5G) wireless networks are the newest mobile technologies proposed for supporting high-data-rate traffic and challenges of previous generations such as spectrum crisis and high energy consumption. Millimeter-wave (mmWave) communication is a promising technology for 5G cellular networks aiming at solving microwave spectrum crisis and providing very high data rates for users. Enabling device-to-device (D2D) communications over mmWave networks can improve the efficiency of these networks. In this article, a new cluster-based architecture capable for D2D mmWave communication (CADM) with TDMA-based medium access control structure is proposed to improve the performance of 5G networks. Using clustering for CADM results in reducing energy consumption and prolonging network lifetime. In addition, enabling simultaneous short-distance mmWave connections on the same frequencies in this architecture not only improves data rates, throughput, and spectral efficiency but also reduces end-to-end delay of 5G mobile networks.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Because the traditional maintenance method of seawalls suffers from problems of insufficient maintenance support ability and significant waste of resources, there is an urgent need to establish a scientific management system for seawalls. Therefore, advanced prognostics and health management (PHM) technology was introduced into seawalls, structure of the seawall PHM system was set up, and the health assessment model and the maintenance decision model of the seawall PHM system were studied. Combining the characteristics of seawalls and high-frequency monitoring information, the seawall health assessment indexes were selected and the weights of health assessment indexes were calculated by projection pursuit model. Then, the health assessment model was set up using fuzzy comprehensive assessment method. The Weibull proportional hazard model was used to link the health state, running time, and failure rate of the seawall. Using maximum availability as the decision objective, the maintenance decision model was established base on the Weibull proportional hazard model. The example analysis shows that the health assessment model can assess seawall health effectively and the maintenance decision model can make correct maintenance decisions in a timely fashion based on the seawall health state.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This communication reports the inhibitive attributes of cinnamaldehyde mitigating corrosion of AISI 1015 carbon steel in HCl (10% w/w) medium. The mild steel coupons were exposed in HCl medium with and without the presence of cinnamaldehyde. Following the exposure, the samples were analyzed for weight loss, potentiodynamic polarization responses, and postmortem surface characterization. The optimal cinnamaldehyde dose and inhibition efficiency were found to be 200 ppm and 95.36%, respectively. The inhibition was assumed to be mainly due to the adsorption of cinnamaldehyde on the metal surface, which followed the Langmuir isotherm. The temperature effects (25–〈span〉 〈span〉\(85\,{^{\circ }}\hbox {C}\)〈/span〉 〈/span〉) data suggested that the binding affinity of cinnamaldehyde on the metal surface was strong. The moderate rise of inhibition efficiency was associated with the chemical adsorption. The value of activation energy 〈span〉 〈span〉\((E_{\mathrm{a}})\)〈/span〉 〈/span〉 obtained was found to be lower than that the value obtained in the inhibitor-free HCl solution. The polarization measurements showed that the inhibitor was virtually mixed type with reduction of cathodic and anodic current densities. The inhibition efficiency, calculated from weight loss and potentiodynamic polarization, was found to be in good agreement with the literature. Scanning electron microscope observations confirmed the existence of a protective adsorbed film of the inhibitor on the metal surface.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Compact heat exchangers are of great technological importance in many industries such as automotive, submarine and spacecraft industry. Micro-channel cooling is an area which is providing a new platform for the development of these compact heat exchange devices. Micro-channel flows and heat transfer characteristics are different from what is usually observed in macrochannel flows. In the present work, computational fluid dynamics is used as a tool to study the influence of variable thermophysical properties on the Nusselt number, skin friction and pressure drop for different channel diameter, fluid inlet velocities, and heat fluxes. The Nusselt number and pressure drop is found to be higher for variable properties as compared to constant properties for an increase in diameters, inlet velocities, and heat fluxes.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In the present research work, two-dimensional boundary layer flow of Jeffrey fluid over a radially stretching disk in the presence nonlinear Rosseland thermal radiation is investigated. The thermal conductivity and viscosity of Jeffrey fluid are considered variable and assumed to be a function of temperature. The self-similar equations are obtained by employing appropriate transformations. These transformed highly nonlinear equations are solved numerically by a powerful technique generalized differential quadrature method. Chebyshev–Gauss–Lobatto spectral method and midpoint method with Richardson extrapolation (RMM) are also adopted to establish the validity and reliability of the numerical solution. The variations of velocity and temperature profiles with the governing parameters such as Prandtl number, variable viscosity and thermal conductivity parameters, heating parameter, radiation parameter, Deborah number and ratio of relaxation to retardation time are presented and discussed graphically. Reduction in momentum boundary layer thickness and velocity of fluid is observed by increasing variable viscosity ratio parameter 〈span〉 〈span〉\(\delta \)〈/span〉 〈/span〉. Velocity of fluid increases, whereas the temperature of fluid decreases with an increase in Deborah number 〈em〉De〈/em〉. The rise in temperature is observed with increasing values of variable thermal conductivity parameter 〈span〉 〈span〉\(\varepsilon \)〈/span〉 〈/span〉, ratio of relaxation to retardation time 〈span〉 〈span〉\(\lambda _1 \)〈/span〉 〈/span〉 and heating parameter 〈span〉 〈span〉\(\theta _{r} \)〈/span〉 〈/span〉.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Lithium–sulfur batteries undergo a complicated electrochemical process while functioning. Their performance varies with electrolytes and the electrode–electrolyte compatibility, and it is not possible yet to assert which kind of electrolyte could lead to the optimum performance of lithium–sulfur batteries. In this work, different sulfur/carbon composites are prepared in both crystalline and amorphous states by heating. The products are systematically studied as electrodes in lithium–sulfur batteries containing two types of electrolytes: ether-based electrolyte and carbonate-based electrolyte. The amorphous composite exhibits less polarization than the crystalline one in both electrolytes and can achieve higher utilization of sulfur in ether-based electrolyte at a low current density and better cycle stability in carbonate-based electrolyte at a high current density. Furthermore, the kinetics, to be specific, the surface activation energy and lithium ion diffusivity of the electrode in those two electrolytes are presented to properly shed light on the electrochemical performance of the composites being investigated.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Induction motors are subjected to thermal, electrical and mechanical stresses during continuous operation. If any of these stresses become excess than normal condition, it is a symptom of commencement of fault in the induction motor. If these faults are not detected at an incipient stage, it may result in the failure of the motor. Turn-to-turn short-circuit faults are the major causes for the stator winding insulation failure. In the proposed work, a novel approach is suggested to detect these faults in the induction motor. In this approach, the discrete wavelet transform (DWT) is performed on the Park’s vector modulus of current signals. The accuracy of DWT can be enhanced by selecting the proper wavelet type and its order along with levels of decomposition. With this context, an attempt is made to investigate the best-suited mother wavelet by testing various orthogonal wavelet functions on simulated signal and justified that the 〈strong〉〈em〉db44〈/em〉〈/strong〉 is to be the best suitable wavelet for the detection of an inter-turn fault in the induction motor. The current signals are obtained experimentally under operating conditions with balanced supply voltages, unbalanced supply voltages, load slip variation and gradual variation in load condition and analyzed. The obtained results show the sensitivity and robustness of the proposed approach. The fault severity factor is also suggested for evaluating the severity of fault in the induction motor.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Heavy metals in drinking water can cause adverse health effects. This study deals with the removal of heavy meals, i.e. 〈span〉 〈span〉\(\hbox {Pb}^{+2}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(\hbox {Ni}^{+2}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(\hbox {Cd}^{+2}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(\hbox {Cr}^{+6}\)〈/span〉 〈/span〉 using locally available Chikni Mitti (Kaolinite). This natural adsorbent was used after grinding and without doing any kind of chemical modification. Optimum conditions including pH, concentration of Chikni Mitti, contact time, and agitation speed were established on experimental basis. Under these optimum conditions, 19.33 mg of 〈span〉 〈span〉\(\hbox {Pb}^{+2}\)〈/span〉 〈/span〉, 16.46 mg of 〈span〉 〈span〉\(\hbox {Ni}^{+2}\)〈/span〉 〈/span〉, 29.16 mg of 〈span〉 〈span〉\(\hbox {Cd}^{+2}\)〈/span〉 〈/span〉 and 37.64 mg of 〈span〉 〈span〉\(\hbox {Cr}^{+6}\)〈/span〉 〈/span〉 were removed per gram of Chikni Mitti used. Langmuir, Freundlich, Temkin, Dubinin–Raduskevich (D–R) and Flory Huggins isotherm models were found applicable on experimental data. Freundlich isotherm fitted best for the adsorption of 〈span〉 〈span〉\(\hbox {Cr}^{+6}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(\hbox {Cd}^{+2}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(\hbox {Pb}^{+2}\)〈/span〉 〈/span〉 whereas for 〈span〉 〈span〉\(\hbox {Ni}^{+2}\)〈/span〉 〈/span〉, both Freundlich and Temkin fitted well. Kinetics of adsorption of 〈span〉 〈span〉\(\hbox {Pb}^{+2}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(\hbox {Ni}^{+2}\)〈/span〉 〈/span〉, 〈span〉 〈span〉\(\hbox {Cd}^{+2}\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(\hbox {Cr}^{+6}\)〈/span〉 〈/span〉 were found to follow second-order kinetics.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Waterpipes have been used to smoke tobacco and other substances by the indigenous people of Africa and Asia for at least four centuries. Waterpipe smoking causes different genotoxic effects. The evaluation of chromosome aberrations (CAs) is one of the standard methods used for assessing the DNA damage in human subjects. The aim of this study was to determine whether waterpipe smoking increases the frequency of different types of CAs in the peripheral blood lymphocytes of young waterpipe smokers (〈span〉 〈span〉\(n=25\)〈/span〉 〈/span〉) compared with non-smokers (〈span〉 〈span〉\(n=25\)〈/span〉 〈/span〉) in Jordan. Twenty-five metaphases were scored and evaluated for chromosome breakage, fragment and gap for each individual. Chromosomal breakage ratios were detected to be 〈span〉 〈span〉\(2.53\pm 1\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(0.576\pm 0.64\)〈/span〉 〈/span〉 in the waterpipe smokers and non-smokers groups, respectively. The fragments ratios were 〈span〉 〈span〉\(2.19\pm 0.9\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(0.72 \pm 0.05\)〈/span〉 〈/span〉, and the gaps ratios were 〈span〉 〈span〉\(2.15\pm 0.67\)〈/span〉 〈/span〉 and 〈span〉 〈span〉\(0.6\pm 0.5\)〈/span〉 〈/span〉 in the waterpipe smokers and non-smokers groups (〈span〉 〈span〉\(p 〈0.0001\)〈/span〉 〈/span〉), respectively. The results of the study revealed a significant increase in the frequencies of different types of CAs in waterpipe smokers compered to non-smokers, suggesting that smoking a waterpipe may cause genotoxic effects.〈/p〉

Description: 〈p〉The original version of this article unfortunately contained a mistake. The family name of the first author was incomplete. The complete family name is “Rajeh Ali” as given above.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉One of the greatest challenges of researchers is to understand the behavior of base isolation systems and base-isolated buildings under the conditions of different ground motions. The specific objective of this study is to evaluate the seismic response of multi-story base-isolated buildings with lead core rubber bearings (LCRBs) and buildings that are not isolated when subjected to different types of ground motions with different components. Under these conditions, the equations of motion of buildings with isolation systems are obtained, and LCRB force–deformation behavior is modeled as bilinear in MATLAB. Then, the behaviors of the base isolation system and base-isolated buildings are evaluated for 45 different earthquake scenarios, which are categorized into three different groups with regard to the ratio of peak ground acceleration to peak ground velocity (PGA/PGV). The dissipation of energy by a base isolation system, which is induced by the earthquake, varies for three different ranges of the PGA/PGV ratio. Despite the fact that by increasing the number of stories, the effectiveness of the isolator system decreases, this paper shows the most important finding to be that the damage limitation requirement is kept below 1% according to Eurocode 8, which is the requirement for buildings at the upper limit on the inter-story drift ratio under seismic loading, and the inter-story drifts significantly decreases for the 〈em〉base-isolated〈/em〉 buildings and even for high-rise buildings.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉A considerable amount of ablution greywater (AGW) is being produced at mosques for cleaning certain parts of the body before performing prayers. In this study, alum coagulation followed by batch and continuous AC adsorption tests was conducted to examine the removal efficiency of turbidity, COD, and BOD to evaluate the recycling potential of AGW. In coagulation experiments, optimal overall removals of turbidity (95.8%), COD (31.6%) and BOD (50.0%) were achieved at 20 mg/L of alum dose. Further, the overall removal efficiencies were enhanced by AC adsorption for COD up to 70.8% and BOD up to 57.2% at 20 min adsorption equilibrium time with 0.2 g/L of optimal AC dose. The adsorption data was well fitted to the pseudo-second-order kinetics model. Both the Langmuir and Freundlich isotherm models were found suitable to characterize the adsorption of COD and BOD on AC. Maximum adsorption capacities were calculated 175 mg/g for COD and 88 mg/g for BOD. Continuous experiments of the AGW treatment process resulted in residual turbidity less than 1 NTU and both the COD and BOD values less than 10 mg/L. Treated AGW was found suitable for unrestricted irrigation, toilet flushing, and firefighting. The estimated cost for a full-scale treatment process (1.02 US$/〈span〉 〈span〉\(\hbox {m}^{3})\)〈/span〉 〈/span〉 came out to be less than the existing cost of water production (1.09 US$/〈span〉 〈span〉\(\hbox {m}^{3})\)〈/span〉 〈/span〉 in Saudi Arabia. The study revealed that the combination of alum coagulation and AC adsorption is a sustainable treatment option for recycling of AGW in arid and semiarid regions.〈/p〉

Description: 〈p〉Unfortunately, Acknowledgment section was missing in the original article. It is given below.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The deployment of Internet Protocol Version 6 (IPv6) has progressed at a rapid pace. IPv6 has introduced new features and capabilities that is not available in IPv4. However, new security risks and challenges emerge with any new technology. Similarly, Duplicate Address Detection (DAD), part of Neighbor Discovery Protocol in IPv6 protocol, is subject to security threats such as denial-of-service attacks. This paper presents a comprehensive review on detection and defense mechanisms for DAD on fixed network. The strengths and weaknesses of each mechanism to Secure-DAD process are discussed from the perspective of implementation and processing time. Finally, challenges and future directions are presented along with feature requirements for the new security mechanism to secure DAD procedure in an IPv6 link-local network.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Machine-to-machine (M2M) communication is now a frequently used term owing to the knowledge of the Internet of Things. As the applications of the M2M increase, the number of M2M devices is predicted to highly increase in the next coming years. Presently, there is an attempt to improve the cellular networks to handle both human-to-human (H2H) and M2M communications. Integrating the M2M communication across the usual H2H communication is an important target owing to the predictable growth in the number of M2M devices that includes the distinctive features of the M2M traffic. To increase the efficiency of the usage of the LTE resource, the same resource is predicted to be used for H2H and M2M communications. Consequently, an efficient resource-scheduling plan is essential to manage an LTE network system including both M2M devices and H2H users. In this paper, we propose a delay-aware time-slotted resource allocation with a priority-based queuing model, which is designed especially for the LTE network including both M2M devices and H2H users. Resource scheduling provides the highest priority to H2H, in contrast to M2M, which is given the lowest priority. The high arrival rate of the users of H2H results in widespread starvation of M2M users; hence, it is likely to transmit some resources to M2M devices by postponing the H2H users up to QoS value, which does not have a negative impact on their quality. In the proposed schemes, the H2H users’ priority is relaxed by delaying them in the LTE network up to the level that does not have a negative impact on the quality of the H2H users. Then, in addition to protecting the H2H users, the proposed schemes can increase the utilization of the M2M resource usage and reduce its average waiting delay. In addition, simulation and analytical models are developed in order to assess the performance measures of M2M in terms of average waiting delay (〈em〉W〈/em〉) and average system delay (〈em〉T〈/em〉). The results show that the proposed schemes provide better M2M performance while controlling the QoS level for H2H services.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Internet of Things (IoT) is known as a hot topic in current decade. As a widely accepted IoT technology, wireless sensor network (WSN) is employed in fire alarming, agriculture, etc. However, how to devise a secure authentication scheme for WSNs is an open issue. In recent several years, authentication schemes about WSN with multi-gateway architecture have turned up. Unfortunately, security weaknesses may happen in historical schemes. Rather than simply improve the old schemes, we present a lightweight authentication scheme for multi-gateway WSNs in this paper. Based on the place of aim sensor, the process is divided into two cases: visiting sensor in and out of the scope of gateway. After the proof with ProVerif and analysis of the security properties, we deem that our scheme is away from usual attacks. Furthermore, the presented scheme is better than other recent schemes by performance comparison and it is practical by simulation study via the famous tool NS-3.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this paper, a new scheme of feature extraction named as sparse Weber-oriented visual features is proposed by the integration of sparse and dense data representations. Image orientation, magnitude and pixel intensity are aggregated in horizontal direction to obtain the feature vector that provides more discriminative information of an image objects. Instead of merely considering individual pixel intensities being highly susceptible to image local variations, orientation is calculated using horizontal and vertical local patches along current pixel. The magnitude component is computed using dense chromatic data representation by second-order symmetric kernel function. Pixels randomly selected from sparse data are binarized with winner-take-all principle to generate feature vector directly from pixel intensities. Experiments using KNN classifier resulted in object recognition accuracy of 94.43%, 96.21% and 71.8% on three standard available colored image datasets that are COIL-100, ALOI and PVOC 2007, respectively. Results evaluation depicts the performance of proposed method as compared to state-of-the-art object recognition schemes.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Liver cirrhosis, the end stage of chronic liver disease, is one of the major risk factors for the development of liver cancer, and may result in premature death. This research proposes a fuzzy fibrosis decision support (F2DS) system. It is a fuzzy knowledge-based expert system for liver fibrosis stage prediction. F2DS is carefully based on a set of knowledge acquisition and machine learning techniques. In addition, the system depends on domain expert knowledge for designing the membership functions and validating the fuzzy knowledge base. It depends on a suitable list of 17 symptoms, and laboratory test features that can accurately and significantly describe fibrosis patients. The experimental results of the expert system were obtained using a real dataset from the Liver Institute, Mansoura University, Egypt, of 119 patients infected by chronic viral hepatitis C. The performance of the system was evaluated with many metrics, achieving a testing accuracy of 95.7%. The evaluation of proposed fuzzy expert system shows its capability of diagnosing the stages of liver fibrosis with a high degree of accuracy, and it can be embedded as a component in a healthcare system to assist physicians in their daily practice. In addition, students training in medicine can benefit from this system.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Intelligent transportation systems are becoming more and more important nowadays. In these systems, vehicles and possibly the infrastructure communicate with each other by vehicular ad hoc networks (VANETs). VANETs are being deployed and widely used in urban as well as in highway applications. Several standard use cases have been identified over the last decade (i.e., alert messages, car following support, data exchange between vehicles). In this paper, we focus on the alert message propagation on the highway. We derive the stationary and the transient solution of the message propagation distance by constant vehicle speed. Since these messages frequently indicate an accident on the road leading to a traffic jam, we extend the model to take the queueing system due to the traffic jam also into consideration. Our analytical results are compared with SUMO-/Veins-based simulations.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this paper, we propose a novel model which adaptively estimates the noise probability distribution and noise parameters from the input image and restores the data accordingly choosing appropriate regularization model designed for it. In most imaging applications the noise characteristics are assumed prior to the restoration process. This assumption is generally based on the previous experimental study of the images from a specific modality. The adaptive detection of the noise distribution from the data makes it robust and highly suitable for automated signal and image restoration systems. The non-local framework implemented using fast numerical solvers catalyzes the convergence rate of the model. Here we analyze three different noise distributions such as Gamma, Poisson, and Gaussian. Among this Gaussian is additive and source independent, Gamma is multiplicative and source dependent, and finally Poisson is data dependent (neither multiplicative nor additive). The model can be extended to the other source-dependent distributions such as Rayleigh and Rician by appropriately tuning it. The experimental results conform to the assumption regarding the noise distribution and noise parameters estimation capability of the model.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Falls represent a major problem for the elderly people aged 60 or above. There are many monitoring systems which are currently available to detect the fall. However, there is a great need to propose a system which is of optimal effectiveness. In this paper, we propose to develop a low-cost fall detection system to precisely detect an event when an elderly person accidentally falls. The fall detection algorithm compares the acceleration with lower fall threshold and upper fall threshold values to accurately detect a fall event. The post-fall recognition module is the combination of posture recognition and vertical velocity estimation that has been added to our proposed method to enhance the performance and accuracy. In case of a fall, our device will transmit the location information to the contacts instantly via SMS and voice call. A smartphone application will ensure that the notifications are delivered to the elderly person’s relatives so that medical attention can be provided with minimal delay. The system was tested by volunteers and achieved 100% sensitivity and accuracy. This was confirmed by testing with public datasets and it also achieved the same percentage in sensitivity and accuracy as in our recorded datasets.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Cloud provides storage facility to its users at a reduced cost, but storing confidential data on the cloud is a security concern. To provide data privacy, the confidential data are encrypted before outsourcing to the cloud. Storing encrypted data in the cloud affects the utilization of data as it makes document searching inefficient. Although recent research has tried to make searching efficient, still there is a trade-off between the search efficiency and search accuracy. As the cloud is based on the pay-per-use model, more is the time required to retrieve the relevant documents more will be the financial burden on end users which affects their cloud-usage satisfaction. In this paper, the concept of keyword binning is proposed where document indexes are assigned to multiple buckets based on the contained keywords and search is performed only in relevant buckets. So, we use the number of comparisons as one of the metrics as it affects the search time. With ranking incorporated, the retrieved results are ranked efficiently and in 84% of the cases 4 out of the top-5 results of the proposed scheme match the 4 results in top-5 plain-text ranked results. For enhanced query privacy, we also propose an efficient query randomization scheme. The experimental results using Reuters-21578 dataset show that the proposed scheme is privacy-preserving and efficient with 100% recall and 98.45% precision.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Conventional food trading platforms face several issues, such as quickly to find trading objects and protect the reliability of transaction information. With e-commerce developing rapidly, food trading has also recently shifted to the online domain. Blockchain has changed many industries owing to its robustness, decentralization and end-to-end credibility. This paper proposes a novel 〈span〉F〈/span〉ood 〈span〉T〈/span〉rading 〈span〉S〈/span〉ystem with 〈span〉CO〈/span〉nsortium blockchai〈span〉N〈/span〉 (FTSCON) to improve trust and security issues in transactions. It uses consortium blockchain technology to set permission and authentication for different roles in food transaction, which meet the challenge of the privacy protection of multi-stakeholders. The algorithm of optimized transaction combination is designed for the purpose of helping users find suitable transaction objects. It can choose the optimized trading portfolio for buyers. The online double auction mechanism is used to eliminate competition. And the improved PBFT (iPBFT) is used to enhance efficiency of system. Moreover, a smart-contract life- cycle management method is introduced, and security analysis shows that FTSCON improves transaction security and privacy protection. Experiment results based on a series of data indicate that the proposed algorithm can achieve profit improvement of merchants.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This article proposes a very high capacity steganography technique using differencing and substitution mechanisms. It divides the image into non-overlapped 〈span〉 〈span〉\(3{\times }3\)〈/span〉 〈/span〉 pixel blocks. For every pixel of a block, least significant bit (LSB) substitution is applied on two LSBs and quotient value differencing (QVD) is applied on the remaining six bits. Thus, there are two levels of embedding: (i) LSB substitution at lower bit planes and (ii) QVD at higher bit planes. If a block after embedding in this fashion suffers with fall off boundary problem, then that block is undone from the above hybrid embedding and modified 4-bit LSB substitution is applied. Experimentally, it is evidenced that the hiding capacity is improved to a greater extent. It is also experimentally proved that pixel difference histogram and RS analysis techniques cannot detect the proposed steganography technique.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Despite the success achieved in the metadata models matching area, large-scale matching does not preserve high match quality and efficiency at the same time. To deal with these challenges, we introduce a generic matching framework, called 〈em〉MetMat〈/em〉, to identify and discover corresponding entities across XML schemas and/or ontologies (metadata models). In particular, the proposed framework is based on a parallelized clustering-based matching approach, which first splits the original matching task into smaller independent tasks. These independent tasks are then carried out in parallel exploiting desktop platform features that are equipped with parallelism enabled multi-core processors. To this end, we develop three different parallel strategies: 〈em〉inter-〈/em〉, 〈em〉intra-〈/em〉, and 〈em〉hybrid-〈/em〉matching strategies. To obtain high quality, a set of matchers are exploited. The proposed framework is validated through an extensive set of experiments over small and large data sets. We also compared the 〈em〉MetMat〈/em〉 framework to top matching tools participating in the OAEI (Ontology Alignment Evaluation Initiative) (http://oaei.ontologymatching.org/) for the last three years. The results show that the 〈em〉MetMat〈/em〉 framework with the 〈em〉intra-〈/em〉parallel matching strategy outperforms other matching strategies in terms of processing time while preserving the same quality. Moreover, the tool acquires a good position through OAEI for the last three years.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Abdominal CT scans have been widely studied and researched by medical professionals in recent years. CT scans have proved effective for the task of detection of liver abnormalities in patients. Computer-aided automatic segmentation of the liver can serve as an elementary step for radiologists to trace anomalies in the liver. In this paper, we have explored deep learning techniques first and foremost for the extraction of liver from the abdominal CT scan and then, consequently, to segment the lesions from a tumour-ridden liver. A cascaded model of convolutional neural networks is used to segment lesions once tumour has been detected in the liver by GA-ANN which has been fed textural liver features using LTEM for its classification procedure. A high DICE index has been obtained of 0.9557 for liver segmentation and 0.6976 for lesion segmentation.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, the problem of critical ambulance routing scheme, which is a significant variant of the quickest path problem (QPP), was investigated. The proposed QPP incorporates additional factors, such as service-level agreement (SLA) and energy cooperation, to compute the SLA-energy cooperative quickest route (SEQR) for a real-time critical healthcare service vehicle (e.g., ambulance). The continuity of critical healthcare services depends on the performance of the transport system. Therefore, in this research, SLA and energy were proposed as important measures for quantifying the performance. The developed algorithm (SEQR) evaluates the SLA-energy cooperative quickest ambulance route according to the user’s service requirements. The SEQR algorithm was tested with various transport networks. The SLAs and energy variation were quantified through the mean candidate 〈em〉s〈/em〉–〈em〉t〈/em〉 qualifying service set (QSS) routes for the service, average hop count, and average energy efficiency.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This article proposes a heuristic for the fixed spectrum frequency assignment (FS-FA) problem of telecommunications networks. A network composes of many connections, and each connection needs a frequency from the spectrum. The assignment of frequencies to the transmitters should satisfy a set of constraints. The constraints specify the separation which is necessary between frequencies of different transmitters. Violation of constraints creates interference. The goal of the FS-FA problem is to find an assignment of frequencies for the transmitters, which has minimum interference. The proposed heuristic has two main components: a local search heuristic and a compound move. The local search heuristic employs one-change moves (i.e., a move that changes the frequency of one transmitter at a time). It also employs a lookup table that classifies all possible one-change moves as positive or negative. The local search heuristic chooses positive/negative moves until it traps in a locally minimal solution. The compound-move operation shifts the local search to a new location in the search space. We can repeatedly apply the local search and compound move for many iterations. The proposed heuristic has been evaluated on the same benchmarks as used by others in the recently published literature. We have compared our algorithm with two existing tabu-search-based algorithms: dynamic-list-based tabu search (DTS) (Montemanni et al. in IEEE Trans Veh Technol 52(4):891–901, 〈span〉2003〈/span〉. 〈span〉https://doi.org/10.1109/TVT.2003.810976〈/span〉) and heuristic manipulation technique-based TS (Montemanni and Smith in Comput Oper Res 37(3):543–551, 〈span〉2010〈/span〉. 〈span〉https://doi.org/10.1016/j.cor.2008.08.006〈/span〉) (HMT). The solution quality of the proposed algorithm is found to be better than or equal to the HMT and DTS in 88% and 79% of test problems, respectively.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Various studies related to the cross-project defect prediction (CPDP) have been done in defect prediction literature. These studies are based on the methodology which takes training and testing data sets from different projects or varied versions of same project that could have same number of features. Configurable parameters of machine learning algorithms should not be disregarded during defect prediction. In this study, the effects of hyperparameter optimization are investigated in CPDP and within-project defect prediction (WPDP). To this end, this work proposes a novel method that shows how hyperparameter optimization should be performed in CPDP. Thus, two new procedures are proposed by regarding the structure of heterogeneous data sets. Firstly, a defect prediction model is established on 20 data sets. Various hyperparameters are optimized and the success of CPDP and WPDP is compared afterward. According to the obtained results: (i) CPDP is averagely superior to WPDP in hyperparameter optimization; (ii) linear kernel of SVM is better than polynomial and radial kernels in terms of hyperparameter optimization; (iii) max tree depth (interaction.depth) is crucial in increasing accuracy if a tree-based algorithm is used.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉We present a new version of Advanced Encryption Standard (AES), called DNAES, based on deoxyribonucleic acid (DNA) sequences with silent mutations. We present how to encode and decode data in a DNA sequence and how to perform the different steps of AES. The proposed cipher has the following features: (1) it can be applied to any type of data (e.g., text, videos, images); (2) it has the same security level as AES; (3) it can be implemented in a biological environment or on DNA computers; (4) because the ciphertext generated by DNAES does not actually change the amino acid sequence of the protein, side effects are avoided; and (5) besides encryption, the proposed cipher can be used to hide data in a DNA sequence.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Sentiment analysis (SA) of natural language text is an important and challenging task for many applications of Natural Language Processing. Till now, researchers have used different types of SA techniques such as lexicon based and machine learning to perform SA for different languages such as English, Chinese. Inspired by the gain in popularity of deep learning models, we conducted experiments using different configuration settings of convolutional neural network (CNN) and performed SA of Hindi movie reviews collected from online newspapers and Web sites. The dataset has been manually annotated by three native speakers of Hindi to prepare it for training of the model. The experiments are conducted using different numbers of convolution layers with varying number and size of filters. The CNN models are trained on 50% of the dataset and tested on remaining 50% of the dataset. For the movie reviews dataset, the results given by our CNN model are compared with traditional ML algorithms and state-of-the-art results. It has been observed that our model is able to achieve better performance than traditional ML approaches and it has achieved an accuracy of 95%.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Image inpainting algorithms based on separated priority are easily misled by image texture information, have poor accuracy in searching for matching patches with high priority and often result in inconsistent texture propagation and edge structure. Additionally, it is difficult to obtain the best-matching patch within a fixed range based on only color information. By considering the attention point of human vision and the statistical information of an image, an image inpainting algorithm based on saliency mapping and gray entropy is proposed. A saliency map is added to the priority stage, which ensures that the parts with strong structural information and visual importance are completed preferentially. The best-matching patch is determined by comprehensively considering the color information and saliency features. The search range of the matching patch is adaptively controlled based on gray entropy. Experiments concerning scratch damage, text removal and large area object removal are compared. The results of the proposed method have better visual effects and are superior in regard to the consistency of the edge structure and texture. The efficiency is similar to methods with a fixed local search range. The objective evaluation results also validate the performance of the proposed method.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper presents a novel approach to classify the leaf shape and to identify plant species using venation detection. The proposed approach consists of five main steps to extract the leaf venation, including canny edge detection, remove leaf boundary, extract curve, and produce hue normalization image and image fusion. Moreover, to localize the edge direction efficiently, the lines that extracted from pre-processing are further divided into smaller segments. Thirty-two leaf images of Malaysian plants are analysed and evaluated with two different datasets, Flavia and Acer. The average accuracy is obtained by 98.6 and 89.83% for Flavia and Acer datasets, respectively. Experimental results show the effectiveness of the proposed approach for shape recognition with high accuracy.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉 Unsupervised co-segmentation is one type of shape segmentation. It segments a set of 3D shapes into meaningful parts and creates a correspondence between parts simultaneously without any labeled data. Clustering-based co-segmentation is based on the correlation analysis in a descriptor space and has received increasing attention. In this paper, we propose a co-segmentation method, in which a transformation network for data representation is trained by extreme learning machine, embedding shape primitives into more discriminant feature spaces, so as to achieve better segmentation performance. Thus, co-segmentation can be implemented by clustering on lower dimensions based on the transformation network, so the execution is more efficient. Moreover, once the transformation network is trained, it can be applied to the data representation acquisition process without re-computing similarity parameters. In order to create and train the transformation network, the correlation of shape primitives is utilized. Therefore, an affinity matrix construction method based on parameter-free and high-efficiency simplex sparse representation is introduced. This construction of correlation avoids the blindness of parameter setting. Experimental results show that the proposed co-segmentation method is effective and efficient. In addition, it also can deal with incremental co-segmentation when the dataset is expanded.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉From the last few decades, people do various transaction activities like air ticket reservation, online banking, distance learning, group discussion and so on using the internet. Due to explosive growth of information exchange and electronic commerce in the recent decade, there is a need to implement some security mechanisms in order to protect sensitive information. Detection of any intrusive behavior is one of the most important activity for protecting our data and assets. Various intrusion detection systems are incorporated in the network for detecting intrusive behavior. In this paper, an analytical study of support vector machine (SVM)-based intrusion detection techniques is presented. Here, the methodology involves four major steps, namely, data collection, preprocessing, SVM technique for training and testing and decision. The simulated results have been analyzed based on overall detection accuracy, Receiver Operating Characteristic and (ROC) Confusion Matrix. NSL-KDD dataset is used to analyze the performance of SVM techniques. NSL-KDD dataset is a benchmark for intrusion detection technique and contains huge amount of network records. The analyzed results show that Linear SVM, Quadratic SVM, Fine Gaussian SVM and Medium Gaussian SVM give 96.1%, 98.6%, 98.7% and 98.5% overall detection accuracy, respectively.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The device-to-device (D2D) communication is a candidate technology to implement 5G standards commercially. To initiate D2D, device discovery is a primary issue and very few algorithms have been proposed for device discovery. A discovery algorithm has many parameters to discover the accurate position of the devices in walking and velocity scenarios. Due to rapid changes in the environment, LOS and NLOS algorithms become complex and accurate discovery ventures. Therefore, it is needed to evaluate the performance of the discovery algorithms. In this paper, a methodological approach is introduced for the performance evaluation of discovery algorithms. The performance evaluation for discovery estimation errors and complexity is evaluated using metrics and parameters, and analysis is made for range-based RSS technique using performance metrics. Discussion of performance evaluation metrics and criteria is analyzed followed by numerical/experimental, simulation models, and the parameters which affect performance and assessment. The metrics and criteria are defined in terms of a discovery signal success ratio, average residual energy, accuracy, and root-mean-square error (RMSE). Two differentiating discovery studies, Hamming and Cosine, are given and contrasted with reference RMSE for evaluation. This paper concludes with a discovery algorithm improvement cycle overview from simulation to implementation. It decreases discovery error 〈span〉 〈img alt="" src="https://static-content.springer.com/image/MediaObjects/13369_2019_4006_Figa_HTML.gif"〉 〈/span〉 and enhances RMSE accuracy by an average of 21%. It also reduces the complexity of 12 pairs by Euclidean distance by 29%. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉With the popularity of location-based social networks, personalized points-of-interest (POIs) recommendation has become an essential online service, providing a wide variety of user preferred check-in locations, namely POIs. However, the sparsity of user-POI matrix makes it difficult to recommend unvisited POIs to users. The availability of the user, social and geographical information offers an unprecedented opportunity to address this problem. In this paper, our goal is to accurately recommend POIs to users with the proper order. To handle this, we propose a practical POI recommendation framework UFC by incorporating User preference, Friend importance and Check-in correlation. UFC combines three fundamental factors and derives an overall prediction score of each user for any POIs. User preference is personalized based on collaboration filtering. As for the friend importance, we argue that intimate friends and distant friends share common influence and thus merge these two different factors to model friend importance. We study the geographical correlation of user check-in behavior in depth and employ a probabilistic model to characterize check-in correlation. Extensive experimental results exhibit a significant improvement in our proposed method compared to other state-of-art POI recommendation algorithms.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper aims to reconstruct paleoenvironmental conditions and sea-level changes over the last 5500 years. Multi-proxy investigations of sediment types, foraminiferal records, geochemistry parameters and paleotidal elevation changes were conducted on a short sediment core KHAR1 (225 cm long) retrieved from the intertidal area of the Al-Kharrar Lagoon. The sediment age was determined using 〈sup〉14〈/sup〉C dating of marine mollusk shells. Results showed that two prominent warming events during AD 750–1500 and 1750–present and a cooling event during AD 1500–1750 were inferred from the variation of benthic foraminiferal composition in core KHAR1. Before 3000 BC interval, the core sediment was deposited under intertidal–subtidal conditions as indicated by the presence of terrestrial sediments (siliciclastic materials), a decrease in subtidal-deep species and a slight drop in the paleotidal elevation about 0.50 cm below the present lowest astronomical tide (LAT). From 3000 to 750 BC, deep-lagoonal species such as 〈em〉S. costigera〈/em〉, 〈em〉T. trigonula〈/em〉, 〈em〉T. serrulata〈/em〉 and 〈em〉S. communis〈/em〉 dominated this interval and co-occurred with a decrease in coarse sand and an increase in muddy substrates, indicating a prevalence of subtidal environmental conditions during the deposition of this interval. With the beginning of the 1st millennium, symbiotic (epiphytic) species started to increase, reaching the highest abundances between AD 800 and 1500. This increase in symbiotic species during the AD 800–1500 interval coincided with a stepwise increase in sea level and may indicate the prevalence of seagrasses associated with the occurrence of warm water due to climate warming prevailed in/around the lagoon during the deposition of this interval that corresponds to the ‘Medieval Warm Period’ (MWP). The MWP was followed by cooler (arid) conditions of the Little Ice Age (AD 1500–1750), causing a decrease in the abundance of the epiphytic species 〈em〉S. orbiculus〈/em〉 and 〈em〉P. planatus〈/em〉 (up to 14%) and a drop in paleotidal elevations. After this, the modern warming conditions prevailed until the present day.〈/p〉

Description: 〈p〉In the original publication of this article, the first author’s name was incorrectly published.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Intelligent video surveillance systems require effective techniques in order to detect objects accurately and rapidly. The most suitable algorithms for performing this task are based on convolutional neural networks. Existing approaches encounter a wide range of difficulties in terms of dealing with different sizes, high definition, or colored images turning these latter slower and less precise. The real-time sensitive application offers an interesting challenge for the optimization of the quality and quantity of previous approaches, thus obtaining an efficient system with regard to surveillance environment. This paper presents a novel, fast, and precise technique for advanced object detection as far as intelligent video surveillance systems are concerned. Thus, we propose the transfer learning of an efficient pre-trained network to appropriate datasets for our application and its integration in the architecture of our algorithm. Accordingly, we implement a fine-tuning on this pre-trained model via replacing the softmax layer and running backpropagation. Then, we compare the results of the previous algorithms using common evaluation parameters. The experimental results reveal that with this technique, we can enhance the precision and the accuracy of object detection in video surveillance scenes to more than 〈span〉 〈span〉\(90 \%\)〈/span〉 〈/span〉. Furthermore, along with dealing with different input dimensions, the detector runs in real time. To conclude, our application of machine learning for intelligent video surveillance systems maximizes their efficiency in highly difficult situations.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Many phytochemicals have medicinal properties including anti-inflammatory, antioxidant and cytotoxic activities. The current study aims to estimate and identify the chemical composition of 〈em〉Calamintha fenzlii〈/em〉 Vis. leaves volatile oil and to evaluate its cytotoxic, anti-inflammatory and antioxidant properties. The volatile oil (VO) of 〈em〉C. fenzlii〈/em〉 leaves was separated using microwave ultrasonic method and the chemical composition was characterized using Gas Chromatography–Mass Spectroscopy method. The anti-inflammatory, antioxidant and cytotoxic activities were determined using a COX inhibitor screening, the DPPH-free radical scavenging and MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-cyrboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) cell viability colorimetric assays, respectively. The chemical constituents of 〈em〉C. fenzlii〈/em〉 VO were dominated by oxygenated monoterpenoid (96.91%). The major chemical components of 〈em〉C. fenzlii〈/em〉 VO were represented by menthone 68.93% and pulegone 23.1%. The cytotoxicity test results revealed that the 23.22, 11.6, 5.8 and 2.9 mg/ml of 〈em〉C. fenzlii〈/em〉 VO treatments induced cell death significantly (〈em〉p〈/em〉 ≤ 0.0001) by 70%, while 1.4 and 0.7 mg/ml induced cell cytotoxicity significantly (〈em〉p〈/em〉 ≤ 0.0001) by approximately 50% and 40%, respectively. The VO showed moderate antioxidant activity with an IC〈sub〉50〈/sub〉 value of 15.38 ± 0.81 µg/ml. The COX-1 IC〈sub〉50〈/sub〉 value was 0.215 µg/ml, while COX-2 IC〈sub〉50〈/sub〉 was 0.241 µg/ml. Our data demonstrate for the first time that the VO of the Palestinian 〈em〉C. fenzlii〈/em〉 plant possesses cytotoxic, anti-inflammatory and antioxidants effects. It is a good source of therapeutic active compounds that could have potential applications in the nutraceutical and pharmaceutical industries. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The selection of parameters for abrasive water suspension jet (AWSJ) machining of GFRP composites is a major aspect to be considered for optimizing the process. Generally, machining of plastics, polymer matrix composites are accomplished by the AWSJ machining carried out in the presence of atmospheric air; however, the existence of air around the AWSJ may lead to expansion of jet which results in increase in the kerf width and surface roughness; thus to overcome this drawback, an effort has been made in the current work to compare the effect of different process parameters on kerf width and surface roughness while using AWSJ techniques for machining glass fibre-reinforced plastic composite submerged in water. The exploratory outcomes have herewith validated the fact that the surface roughness and kerf width diminishes in under water machining when contrasted with that of free air machining; this is majorly attributed to the fact that the jet diameter reduces in under water AWSJ machining, thereby reducing the kerf width and surface roughness for optimized values of the parameters of speed, feed and standoff distance. Further, the experimental trials have clearly shown that the AWSJ machining used with an optimized set of parameters yields better machining capabilities as compared to abrasive water jet machining. 〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉In this study, the mechanical properties of the air spring used in secondary suspension systems in railway vehicles have been experimentally determined. Firstly, rubber recipes with different components were determined for the production of rubber material, the main raw material of the air spring. Afterward, the mechanical properties of the elastomer material to be used in the manufacture of the air spring were determined by uniaxial tensile tests and RPA (rubber process analyzer) tests were applied to the samples obtained from different types of rubber compound. The machines used for the production of air spring and the test machines used for determining the mechanical properties of the air springs were specially produced and commissioned within the scope of the study. Blasting, airtightness, lifting–expansion, vertical spring coefficient, horizontal spring coefficient and lifetime tests were carried out by using these test machines.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Based on the mass point cloud data, this paper proposes a hybrid octree mixing point cloud index structure which combines the KD-tree spatial segmentation idea to realize the efficient management of mass point cloud. In this paper, the space of the point cloud is firstly divided by the KD-tree idea. On this basis, the octree is used for further segmentation to establish an octree-like index structure. Then the point cloud dataset is spatially encoded using the improved encoding to achieve better spatial management and neighborhood search. Finally, using five groups of incremented point cloud set as test data, the experimental results and comparison analysis show that the octree-like space can make the overall structure of the data organization more reasonable, effectively improve the access efficiency and reduce the occupancy of memory space. The index structure not only improves the speed of the traditional KD-tree construction index but also improves the problem that the traditional octree is too large for space occupation and the neighborhood search takes too long. It achieves reasonable management of massive point cloud space.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This paper proposes an induction machine stator inter-turn short-circuit fault diagnosis and tolerance based on sliding mode. A Lyapunov stability-based integral sliding mode control is designed and kept in a healthy and faulty case. An online diagnosis using a high-order sliding mode observer allows the fault detection and phase identification on the one hand and provides signal alarm on the other. When the fault overcome such level, the proposed control cannot deal with the inter-turn short-circuit fault. So, it should be reconfigured. The signal alarm triggers the switch between affected stator current and healthy reconstructed ones. Then, fault impact will compensate and the integral sliding mode control still achieves the objectives. The simulation results are presented to illustrate the proposed fault-tolerant design.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The objective of this paper is to model a nonlinear computer numerical control machine tool (CNCMT) system for milling process. A modified internal model control (M-IMC) technique is proposed for position control of machine table. The study of milling process is mainly focused on the cutting mechanics and dynamics. The performance of CNCMT system is degraded due to the presence of disturbance like cutting force and parametric uncertainty. Considering the limitation of conventional internal model control (C-IMC) technique that is the poor performance under constant disturbance, an M-IMC technique is designed for the rejection of disturbance and position control of uncertain nonlinear CNCMT system. The performances of nonlinear uncertain CNCMT system using M-IMC technique is also compared with C-IMC and Ziegler–Nichols-tuned proportional–integral–derivative control techniques. The proposed M-IMC technique is designed to attain the better disturbance rejection capability, i.e., regulatory control with less control effort for the regulation of desired position of a machine table.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Water injection is one of the most economical and effective methods of ensuring the continuous and stable production of an oil field and improving oil recovery. However, scale formation is unavoidable in long-term water injection, and this seriously affects and restricts oil field development. Our research on scale formation in injection–production units was based on the dissolution–precipitation equilibrium, thermodynamics, ionic association theory, the solubility product rule, and the common ion effect. Considering formation temperature, pressure, scale ion concentration, and rate of flow as influencing factors, we established a formation pressure field model, a temperature field model, a porosity model, a scale formation model, and a scale inhibition model, which together constitute a numerical model of scale formation in an injection–production unit. We then used MATLAB software to analyze the influence of various factors on the total amount of scale, the scale range, and the scale distribution, as well as the influence of scale formation on the apparent injectivity index and permeability. To verify the reliability of our model, we introduced a scale inhibition rate, and we compared the scale inhibition rate that we calculated with the scale inhibition rate measured by experiment. The simulation shows that scale formation is mainly affected by formation temperature and scale ion concentration distribution, but that formation pressure has relatively little influence on it. Formation pressure decreases gradually along the direction of water flooding in an injection–production unit, and formation temperature changes mainly near the wellbore of the injection well. Along the direction of water flooding, scale formation first increases rapidly and then decreases rapidly. The reason for this trend is that with low formation temperature near the injection well, a small dissolution equilibrium constant and a high flow rate make scale formation difficult. Radially outward, the formation temperature increases and the flow rate decreases greatly, making it easier for scale to form. Even further out, the scale ion concentration is lower than the minimum scale concentration and scale can no longer form.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The objective of the presented paper is to develop a multiattribute decision-making (MADM) method under the intuitionistic fuzzy set (IFS) environment using the set pair analysis (SPA) theory. IFS can express the uncertain information in terms of membership grades, while the connection number (CN) based on the “identity,” “discrepancy” and “contrary” degrees of the SPA theory handles the uncertainties and certainties systems. Meanwhile, capturing the relationship between the values during the aggregation is a prominent advantage of the power aggregation operator. Motivated by these primary characteristics, in this paper, we develop some power geometric aggregation operators namely for aggregating the CNs, namely, CN power geometric, CN weighted power geometric and CN ordered weighted power geometric operators. A few properties like idempotency, commutativity and boundedness are established to show the viability and legitimacy of developed operators. Afterward, we develop a decision-making (DM) approach based on the proposed operators for tackling the MADM issues under the intuitionistic fuzzy numbers environment. Finally, real-life case of MADM problem has been discussed to manifest the developed DM approach, and obtained results are compared with the results that are obtained by the existing DM methods for showing the feasibility and validity of the developed DM approach.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Thermoelectric devices are currently being used in cooling and generating electricity applications. This study mainly focuses on using thermoelectric devices for both applications towards cooling down computer chips; especially, that the very large scale integration technology has reached high advancement where more than 100 million transistors can be fabricated in 1 mm〈sup〉2〈/sup〉. Reducing the non-uniformity of the chip temperature is important so as to decrease the induced thermal stress in this chip and consequently reduce its failure rate. To simultaneously reduce both the non-uniformity of the temperature distribution in the chip and the power requirements for the cooling system, thermoelectric generators can be installed on the cooler chip areas to harvest electrical power from the chip wasted heat. Thereafter, the chip hotspot areas are cooled down using thermoelectric coolers that are powered by the harvested electrical power from the thermoelectric generators in order to maintain the temperatures of these hotspots to be less than or equal a certain temperature threshold. Because no additional electrical power requirement is needed to cool down the hotspots, this cooling technique is called in this paper as “sustainable self-cooling framework for cooling chip hotspots”. However, the question is that can the harvested electrical power by the thermoelectric generators be enough to power the thermoelectric coolers for different computer chips at a given operating condition? As such, one of the objectives of this paper is to develop a three-dimensional numerical and optimization model to predict the thermal and electrical performance of cascaded and non-cascaded thermoelectric generators and cascaded and non-cascaded thermoelectric coolers for cooling chip applications. Then, validate the developed model against experimental data. The results showed that the predictions of the developed model were in good agreement with the experimental to within ± 4%. After gaining confidence in the developed model, it was used for a given chip operating condition to conduct a case study for a sustainable self-cooling framework in order to answer the raised question above. The results showed that the self-cooling framework can successfully cool down the hotspot at an acceptable temperature with not only no need for additional electrical power requirements but also for reducing the non-uniformity in the chip temperature distribution.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This manuscript presents a theoretical modeling of conversion efficiency improvement in a typical polycrystalline Si solar cell in 1〈em〉D〈/em〉 assumptions under multispectral sunlight illumination. The improvement is brought by the increase in the collection of the minority carriers charge in excess. This increase is the consequence of the integration of the electric field provided by the use of the open-circuit photovoltage of another silicon solar cell. We assume that two silicon solar cells are integrated to the system. The first solar cell provides the open-circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This study has shown that the photocurrent generated is improved by the conduction current given by this electric field. It shows that an improvement in the electric power, particularly its maximum value, leads to the improvement in the conversion efficiency and the fill factor. We observe an improvement in the second silicon solar cell performances for the shortest distance between both aluminum conductors.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉Biochar pyrolyzed at 800 °C from banana (〈em〉B〈/em〉〈sub〉〈em〉b〈/em〉〈/sub〉) and orange peel (OP〈sub〉〈em〉b〈/em〉〈/sub〉) was applied in the sorption of nickel (Ni〈sup〉2+〈/sup〉) using a batch system. OP〈sub〉〈em〉b〈/em〉〈/sub〉 shows a higher affinity for Ni〈sup〉2+〈/sup〉 than 〈em〉B〈/em〉〈sub〉〈em〉b〈/em〉〈/sub〉. A rapid increase in sorption capacity and percentage removal was observed for both types of biochar with an equilibrium time of 30 min. The adsorption behavior was described using a pseudo-second-order model, indicating chemisorption as the rate-limiting step. A linear increase in the sorption capacity of 340 and 212 mg g〈sup〉−1〈/sup〉 was observed for OP〈sub〉〈em〉b〈/em〉〈/sub〉 and 〈em〉B〈/em〉〈sub〉〈em〉b〈/em〉〈/sub〉, respectively, upon increasing the initial Ni〈sup〉2+〈/sup〉 concentration (50–300 mg g〈sup〉−1〈/sup〉) with a 40% decrease in removal efficiency. An increase in the sorption capacity of 78 and 88 mg g〈sup〉−1〈/sup〉 for OP〈sub〉〈em〉b〈/em〉〈/sub〉 and 〈em〉B〈/em〉〈sub〉〈em〉b〈/em〉〈/sub〉, respectively, with a 15% increase in removal efficiency was observed for both absorbents upon increasing the solution pH from 2 to 8. OP〈sub〉〈em〉b〈/em〉〈/sub〉 shows enhanced performance than 〈em〉B〈/em〉〈sub〉〈em〉b〈/em〉〈/sub〉 at all pH values, and an optimum pH of 8 was selected. An increase in the sorption capacity of ~ 120 mg g〈sup〉−1〈/sup〉 was observed upon increasing the biochar dose (0.1–0.5 g), and the optimum dose was 0.7 g. The Langmuir isotherm model exhibits the best fit to the adsorption data (〈em〉R〈/em〉〈sup〉2〈/sup〉 = 0.99), whereas H–J isotherm (〈em〉R〈/em〉〈sup〉2〈/sup〉 〈 0.70) displayed the least best fit. The effective sorption of Ni〈sup〉2+〈/sup〉 demonstrates the potential of plant-based biochar as economically viable adsorbents.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉The multilayer thin film coatings are one of the proven technologies for improvement in solar thermal and optical applications. In current solar thermal and optical systems, multilayer thin film coatings find application in many functions such as photovoltaics, heat exchangers, filters, sensor technologies, laser windows, mirrors, reflectors and optics for digital projections. The solar absorptance and thermal emittance of the multilayer thin film coatings are one of the leading factors for its applicability in said areas. The processing conditions, morphology and surface finish influence the solar absorptance and thermal emittance behavior of multilayer thin film coating. Therefore, emphasis has given in this paper to deposit multilayer thin film coatings with an increased solar absorptance and decreased thermal emittance to improve its applicability in solar thermal applications. Multilayer thin film coatings (Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/Ni/W–Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/W) were deposited using DC/RF magnetron sputtering on the stainless steel substrate to improve its applicability in solar thermal receiver tube for power generation. The performance of this multilayer thin film was investigated by measuring the absorptance and emittance using 410 Solar and ET 100 in the solar spectrum region at a variable incident angle from 20° to 60°. The effect of optical properties, microstructure and morphology of the multilayer thin film coatings was also investigated. The maximum absorptance 0.92 and minimum emittance 〈 0.1 were observed in deposited multilayer thin film coating with the combination of Tungsten, Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and Nickel, respectively. The observed values indicate the practical applicability of the multilayer coatings in medium-to-high-temperature range of solar thermal receiver tubes.〈/p〉

Description: 〈h3〉Abstract〈/h3〉 〈p〉This study objectively and subjectively investigates the factors influencing motorcyclists’ safety on expressways. The relationships between motorcyclist stress while driving on expressways and potential influencing factors including traffic situations, road geometries, and wind conditions are also investigated. Data collected from a historical crash database and through a field experiment were used for the analyses reported in this paper. A special device was used during the experiment to measure the motorcyclists’ stress levels and to collect required information such as location, speed, and surrounding traffic. Statistical analyses conducted on motorcyclists’ subjective safety perception, obtained through a questionnaire survey, highlighted that the degree of risk from surrounding vehicles was the most significant influencing factor, followed by vibration caused by road surface asperity. Furthermore, the analysis on motorcyclists’ stress level indicated that the significant influencing factors are the proportion of traveling time on the climbing lane, the proportion of traveling time in which the adjacent left lane is occupied by a heavy vehicle, and the variations of instantaneous speeds.〈/p〉