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[en] 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 s–t qualifying service set (QSS) routes for the service, average hop count, and average energy efficiency.
[en] Conventional seismic interpretation provides subsurface geometric information, while quantitative seismic interpretation can provide lithologic and fluid information, including saturations, porosity, density, Poisson’s ratio and other elastic parameters. Rock physics is the main science behind quantitative interpretation and includes a number of transforms, in the form of empirical relations, for the computation of various rock properties. In addition, crossplot templates of these properties help in facies modeling and reservoir characterization. This paper presents rock physics transforms between compressional velocity, shear velocity, density, porosity, resistivity and gamma ray radiation for Cretaceous to Miocene strata in the Indus offshore area, Pakistan. These transforms are empirical relations established through regression analysis between various petrophysical parameters. Logs from twelve wells have been used in the analysis to give a good representation of rock properties in the area. Most of the relations have a linear correlation coefficient above 0.74 and therefore can be used reliably in quantitative interpretation of seismic data.
[en] Hastelloy C-276 superalloy has a wide range of applications including petroleum and petrochemical industries. Since welding forms an essential fabrication method for joining different structures in these industries, selection of suitable welding parameters is a prime concern that is yet to be addressed for Hastelloy C-276. In the present study, optimization of process parameters for electron beam welding of 2.6-mm-thick Hastelloy C-276 sheet has been carried out to obtain weld bead having through-penetration and minimum weld (or melt) zone cross-sectional area. A simple optimization technique is employed in the present study to solve the multi-objective minimization problem. After carrying out the full factorial experiment using selected process parameters, various geometric elements of the weld bead are identified as the output responses. The regression equation is developed for each geometric element from the experimental data. The desired value of a geometric element is specified as a constraint for the corresponding regression equation. A number of regression equations (considering all the geometric elements) are solved in parallel to obtain an optimized set of process parameters, followed by a confirmation test. Further, the optimized melt zone is subjected to cyclic potentiodynamic polarization test to study its susceptibility to localized corrosion. It is observed that polarization curve characteristics of base metal and optimized melt zone are not significantly different; however, the repassivation potential of the melt zone is less than that of the base metal. A flowchart showing the layout of the employed optimization technique followed by corrosion test is attached. .
[en] In this study, a laboratory-scale continuous-flow, mixed-growth biological treatment process, based on the integrated fixed-film activated sludge (IFAS) process, was configured using granular activated carbon as the attached-growth media. With potential to degrade target organics, the application of this process for treating the petrochemical industry wastewater may provide a flexible, more efficient, and inexpensive replacement for the activated sludge and other biological treatment processes. The laboratory-scale IFAS configuration was experimented to evaluate the process ability to enhance the biodegradation process utilizing both suspended growth and attached growth, to evaluate its ability to remove nitrogen and phosphorous, and to identify conditions of predominance of attached versus suspended growth. Ratios of attached to suspended growth reached 3 at steady-state conditions; the laboratory-scale flow-through column reached a steady-state operation in 1–2 h, promising smaller tank volumes on a large-scale application. The organics’ removal rates were found to be sensitive to higher initial concentrations and higher hydraulic loading within the range tested in this work. However, nitrogen and phosphorous removal rates were low, and it was mainly attributed to the low total phosphorous-to-chemical oxygen demand ratio representing the bottleneck for upscaling this process.
[en] Decentralized control of DC microgrid (dcµG) using hybrid renewable energy sources (RES) and battery energy storage system (BESS) which operate with and without grid-connected mode is proposed in this paper. In dcµG integrated with multiple RES and BESS, fluctuating output characteristics of the distributed generations (DGs) due to changing input conditions and the dynamic interactions of the source and load interface converters are main factors which cause stability problem of DC bus voltage. Thus, to solve this problem, the decentralized control scheme which uses bus voltage level as communication link in the control law is proposed in this paper. Accordingly, the control method realizes different operating modes based on the available generations and load demand. Maximum power and constant voltage controls schemes are applied in the DGs interfacing control to regulate the power and voltage variations due to changing input conditions. Furthermore, in the control strategy, the source and battery interfacing converters are controlled autonomously using the bus voltage level without any communication. This maintains the reliability and flexibility of the system. The proposed system model is developed with Matlab/Simulink SimPowerSystem and simulated with real-time simulation using OPAL-RT.
[en] Two diallylamine salts, diallylammonium acetate (DAA acetate) and diallylguanidinium acetate (DAGA) were cyclocopolymerized in water with acrylonitrile (AN) using power ultrasound in order to prepare acrylonitrile copolymers involving thermally stable heterocyclic rings in their polymeric matrix. The structural characterization of the copolymers was performed using FTIR, C NMR, UV/Vis spectroscopy and elemental analysis. The results revealed that the diallyl amine salts cyclopolymerized to form pyrrolidine and not piperidine rings throughout the polymeric chains. The thermal behavior of the copolymers prepared under nitrogen atmosphere was investigated using thermogravimetry, differential thermal analysis (TGA/DTA) and differential scanning calorimetry. The morphological property was also discussed using scanning electron microscopy (ESEM). The results revealed that the thermal stability of the copolymers was improved by the increase in the content of N,N-diallylammonium and N,N-diallylguanidinium acetate. The power of ultrasonic waves enhanced the homogeneity of the copolymers blend films irrespective of the copolymer compositions.
[en] SCP is one of the significant factors affecting the integrity of subsea wellhead in deepwater wells. In this paper, a new model has been established for predicting the SCP in multilayer casings based on the Darcy percolation flow model and the pressure–volume–temperature equation of state, in which the effect of inter-coupling compression of multilayer casing and volume change of annulus and casing has been considered. An iterative calculation computer program is coded for solving the model. On this basis, the influence of the gas migration parameters, the casing program, the physical properties of fluid in the annulus, and the cement permeability on the SCP is discussed, respectively. Analysis results show that the gas migration has a significant influence on the SCP, which indicates that the importance of the cement sealing performance to the integrity of subsea wellhead. In particular, the gas migration would cause the SCP increase at the beginning and then tend to be stable finally. The increase in the cement permeability, fluid density, or cement top can decrease the time when SCP reaches to stability. On the contrary, the high fluid bulk modulus can increase the time. Casing deformation provided additional annular space for gas migration, the calculation results agree well with field data, and the study provides guidance for the casing program design, the cement job, and the prediction and control of the wellbore integrity in deepwater wells.
[en] In machining operations, mechanically clamped, brazed and bonded cutting tools are utilized. The bonded cutting tools have some advantages over the others especially in precision processes. But, there is not much application due to their low joint strength. Therefore, in this study, turning performance of bonded cutting tools was investigated. Nanographene particle-reinforced epoxy or multi-walled carbon nanotube (MWCNT) particle-reinforced epoxy-based nanocomposite adhesives were produced to enhance the adhesive shear strength and joint tensile strength of epoxy adhesive. Steel–cemented carbide (WC, tungsten carbide)–steel single lap joints were produced by applying these nanocomposite adhesives and neat epoxy-based adhesive to specify the optimum amount of nanoparticle reinforcement. Then, machining operations were performed with inserts attached to the tool holder with mechanical clamping method, neat epoxy adhesive and epoxy-based nanocomposite adhesives by utilizing a CNC lathe. The cutting forces, cutting temperatures and surface roughnesses were measured, and the results were compared by each other. Depending on the experimental results, lower cutting forces and surface roughnesses occurred when using bonded cutting tools than that obtained when using mechanical clamping due to damping properties of the adhesive layer. However, the cutting temperatures measured on the bonded cutting tools were higher than that measured on the mechanical clamped cutting tools because of the low thermal conductivity of the adhesive layer. In addition, it was observed that the nanoparticle-reinforced epoxy-based nanocomposite adhesives increased the cutting forces and surface roughnesses a little in comparison with the neat epoxy adhesive due to increasing the viscosity of the neat epoxy and decreasing the damping properties and also decreased the cutting temperatures due to having high thermal conductivity of nanoparticles. When compared the nanoparticles, nanographene adsorbing better on the adherend surface and providing more homogeneous distribution in the matrix gave better results than MWCNT particles.
[en] Firefly algorithm (FA) is an easily implementable, robust, simple and flexible technique, but the major drawback associated with this technique is the imbalanced exploration and exploitation during firefly position changing stage. This imbalanced relation degrades the solution quality which ultimately results in either skipping the most optimal solution even present in the vicinities of the current solution or trapping the solution in the local optima. In this paper, this issue is resolved by introducing genetic algorithm (GA) operators namely selection, mutation and crossover operators in the firefly position stage of the standard FA. The performance of the proposed approach has been tested on energy consumption optimization and user comfort management inside smart building and has been compared with the standard FA, GA, artificial bee colony (ABC) and ant colony optimization (ACO) algorithm in terms of temperature, illumination, air quality and total power consumption minimization and user comfort maximization. The minimum, average, maximum and total power consumption and minimum, maximum and average user comfort were the performance evaluation parameters. The least amount of 145.39 kilowatt hour (kWh) of total power consumed for temperature control was observed for the proposed approach followed by ACO, ABC, FA and GA where the power consumed for temperature was observed as 173.68 kWh, 179.27 kWh, 181.93 kWh and 188.95 kWh, respectively. Similarly, for illumination control, the consumed power for the proposed model was 118.30 kWh followed by FA, ABC, ACO and GA where the power consumed was 146.93 kWh, 162.96 kWh, 169.28 kWh and 193.53 kWh, respectively. For air quality control, the minimum power of 186.94 kWh was found for the proposed algorithm followed by FA, ABC, ACO and GA where the power consumed was 229.01 kWh, 234.38 kWh, 240.47 kWh and 244.76 kWh, respectively. Likewise, maximum user comfort was observed for the proposed technique with the value of 0.94004/1 followed by ACO, ABC, FA and GA where the user comfort recorded was 0.939655/1, 0.93878/1, 0.938314/1 and 0.937896/1, respectively. The statistical analysis shows the efficiency of the proposed model for power consumption minimization and user comfort maximization.
[en] The adaptive cruise control (ACC) system is currently one of the most common research topics in automotive industry. The ACC system tracks the velocity of preceding vehicle by adjusting the throttle angle and applying brake, whenever needed. This system is acknowledged for improving the fuel efficiency due to coordination between brake and throttle. Inappropriate switching between brake and throttle results in loss of energy that increases fuel consumption. To address aforesaid problem, novel coordinated switching controllers for the ACC system are proposed that enhances the fuel efficiency. Moreover, the proposed control strategies are compared for various traffic scenarios, and then, fuel economy is observed for the proposed control schemes. Fuel economy is investigated using switching control paradigm design; namely, the proportional–integral–derivative (PID) controller, adaptive proportional–integral–derivative (APID) controller, and fuzzy PID controller for actual nonlinear and linearized model of the ACC system for various traffic scenarios including stop and proposed control strategies are compared using performance indices for various traffic scenarios, such as CC, ACC, and ACC stop and go in order to show the validity of the design. Furthermore, the comparison among the PID, APID, and fuzzy PID control schemes is investigated to analyze fuel economy of the actual nonlinear CC and ACC system.