High-temperature performance of gilsonite-modified asphalt binder and asphalt concrete

This article investigates the effect of addition of gilsonite (natural bitumen) to asphalt binder on its rheological behavior at high temperatures through construction of complex modulus (G*) master curve using dynamic shear rheometer (DSR) test. This impact is further investigated by evaluation of performance of asphalt concrete modified with gilsonite at elevated temperatures using repeated dynamic creep test. The results showed that introduction of gilsonite to asphalt binder increases its stiffness and elasticity. Also, the results indicated that the modification of asphalt concrete with gilsonite improved rutting resistance significantly.     

Real-Time and Intelligent Flood Forecasting Using UAV-Assisted Wireless Sensor Network

The Wireless Sensor Network (WSN) is a promising technology that could be used to monitor rivers’ water levels for early warning flood detection in the 5G context. However, during a flood, sensor nodes may be washed up or become faulty, which seriously affects network connectivity. To address this issue, Unmanned Aerial Vehicles (UAVs) could be integrated with WSN as routers or data mules to provide reliable data collection and flood prediction. In light of this, we propose a fault-tolerant multi-level framework comprised of a WSN and a UAV to monitor river levels. The framework is capable to provide seamless data collection by handling the disconnections caused by the failed nodes during a flood. Besides, an algorithm hybridized with Group Method Data Handling (GMDH) and Particle Swarm Optimization (PSO) is proposed to predict forthcoming floods in an intelligent collaborative environment. The proposed water-level prediction model is trained based on the real dataset obtained from the Selangor River in Malaysia. The performance of the work in comparison with other models has been also evaluated and numerical results based on different metrics such as coefficient of determination (), correlation coefficient (), Root Mean Square Error (), Mean Absolute Percentage Error (), and are provided.     

A New Supercritical Carbon Dioxide Brayton Cycle with High Efficiency

Designing new and efficient heat engines and increasing the efficiency of previous ones is one of the researchers’ interests in the field of thermodynamics. In this regard, what is mainly concerned is to design a cycle with the positive features of previous cycles, such as less pollution, and higher power‐to‐weight ratio and efficiency. One of these cycles is the supercritical carbon dioxide cycle (SCDC). The main goal of this research is designing a highly efficient SCDC with pessimistic and relatively optimistic efficiencies of 45% and 47%. This paper includes the complete first law analysis of the designed cycle, designing and discussion of efficiency improvement methods and comparison of SCDC with other power cycles. The sensitivity of the cycle efficiency to some important parameters has also been studied.     

Graphite Nanosheet as Low Shrinkage Additive,Curing Accelerator,and Conducting Filler for Unsaturated Polyester Resin

The effect of graphite nanosheets on electrical properties, curing behavior, and polymerization shrinkage of unsaturated polyester resin has been investigated. A solution of polystyrene was used as low profile additive to reduce shrinkage. The results showed that graphite nanosheets have been well dispersed/distributed in the unsaturated polyester matrix where they have high aspect ratio and high surface area. Graphite nanosheet exhibited an accelerating effect on the curing of unsaturated polyester and reduced the polymerization shrinkage as low as 3.6%. Despite large reduction of flexural properties by low profile additive, graphite nanosheet considerably increased the flexural strength and modulus of unsaturated polyester/low profile additive by 47 and 103%, respectively. Therefore, graphite nanosheet can be used as a new low profile additive for unsaturated polyester resins where it is also able to improve mechanical properties and curing rate.     

Numerical Analysis of Amirkabir Plasma Focus (APF) Device for Neon and Argon Gases

In this paper the experimental results in different working conditions in Amirkabir Plasma Focus (APF) Device have been compared with the numerical results of a two-dimensional simulation code based on Lee’s model. The experiments were done with pure Neon and Argon as operating gases over a wide range of working conditions (gas pressures and discharge voltages). It is observed that by a proper choice for values of the efficiency factors, comparison between numerical and experimental results shows a good agreement.     

Surface Plasmon Resonance Magneto-Optical Kerr Effect in Au/Co/Au Magneto-Plasmonic Multilayer

Surface plasmon resonance magneto-optical Kerr effect is studied in magneto-plasmonic multilayer as Au (11 nm)/Co (11 nm)/Au (11 nm). Our experimental setup is consists of spectral magneto-optical rotation in Kretschmann-based attenuated total reflection condition as surface plasmon resonance magneto-optical Kerr effect. Based on this new experimental setup, the sample exposed under external magnetic filed at surface plasmon resonance angle. Our results show sufficient surface plasmon resonance magneto-optical Kerr effect in visible region, thanks to the resonant excitation of surface plasmons which is very suitable for miniaturized and controllable magneto-optical imaging systems, memory, and also magneto-optical isolators.     

Effect of low-temperature oxidation on the pyrolysis and combustion of whole oil

Low-temperature oxidation (LTO) of the Fosterton crude oil mixed with its reservoir sand has been investigated in a tubular reactor. Reservoir sand saturated with 15 wt% of crude oil (20.5° API gravity) was subjected to air injection at low-temperature (220 °C) for a period of time (17 h and 30 min), resulting in the formation of an oxygenated hydrocarbon fuel. The vent gases were analyzed for the content of CO, CO₂, and oxygen and the residue was analyzed to determine the elemental composition and calorific value. The presence of LTO region was verified from the values of apparent H/C ratio. In addition, thermal behavior and combustion kinetics of the residue was investigated using thermogravimetric analysis (TGA). TG involves both non-isothermal and isothermal analysis and kinetic data was derived from isothermal studies. The general model for nth order reaction was used to obtain the kinetic parameters of the coke oxidation reaction. The activation energy, frequency factor and order of the reactions were determined using the model.     

An empirical model for modified bituminous binder master curves

Modeling the mechanical behavior of asphalt binders and mixtures has been the subject of intensified research in recent decades. Master curves of the norm of the complex modulus |G*| in the linear viscoelastic domain are frequently used for modeling, while phase angle master curves are less frequently considered for this purpose. Therefore in this research, an empirical model is introduced for phase angle master curves of modified and neat bituminous binders. The model is based on a general form of a double-logistic (DL) mathematical function. The |G*| master curve was then modeled using a mutual relationship between the phase angle and |G*|. Master curves of three neat and seven modified binders were generated and used to validate the DL model. The results showed that the model is capable of properly predicting the plateau region of phase angle master curves. In particular, the asymptotic behavior of the master curves at high frequencies can be modeled correctly. The model also describes irregularities in the high temperature range of the phase angle master curve. In general, model outputs such as the phase angle value at the plateau, glassy modulus, rheological index and crossover frequency correctly predict the behavior of the neat and modified binders.     

Scalable video transmission over multi-hop wireless networks with enhanced quality of experience using swarm intelligence

In this work, we take the advantages of the particle swarm optimization method which belongs to the family of swarm intelligence algorithms to find improved solutions for delivering digital video content with enhanced quality of experience to the end users over error-prone multi-hop wireless networks. In video transmission over such wireless networks, many network-based (packet loss, delay, etc.) and source-based (encoding quantization level, etc.) parameters can impair the perceived video quality. The main contributions of the proposed work are twofold. At first, an optimal bandwidth allocation framework is being developed based on the particle swarm optimization algorithm in which by incorporating an accurate video quality metric, the total weighted quality of experience of some competing video sources is being optimized. Secondly, these optimal rates have been used for differentiated quality of experience enforcement between multiple competing scalable video sources. The resulting optimal rates can be used as rate-feedbacks for on-line rate adaptation of a moderate scalable video encoder such as H.264/MPEG4 AVC. The aforementioned weight parameters are selected based on the importance of each video sequence's quality and can be associated with some previous service level agreement based prices. Some guidelines about the practical implementation of the proposed algorithm are given. Numerical analysis has been performed to validate the theoretical results and to verify the claims.     

Operation Parameters on CO2-Foam process

Reducing the mobility of CO₂ by means of generating in situ foam is an effective method for improving the oil recovery in CO₂ flooding processes. Implementation of the CO₂-foam technique typically involves the co-injection of CO₂ and surfactant solution into the porous medium. The surfactant molecules form bubble films that trap the flowing CO₂ molecules. The effectiveness of the CO₂-foam process is measured in terms of foam mobility. The mobility of CO₂-foam is affected by different operation parameters, such as pressure, temperature, foam quality, and brine concentration. However, surfactant type governs the overall efficiency of the CO₂-foam process. This paper presents the results of a series of experiments conducted to study the effect of various parameters on the CO₂-foam process. Bottle tests were conducted for four commercially available surfactants and among them, Chaser CD-1045 was found to be the most effective surfactant for CO₂-foam flow under reservoir conditions. It was observed that an increase in pressure from 1, 200 psi to 1, 500 psi leads to increase of the mobility of CO₂-foam, and an increase in temperature from 72 to 122°F reduces the mobility. Also, as the foam quality increases from 20 to 80%, the mobility decreases. It was observed that there was no significant effect on the mobility with an increase in brine concentration from 1 to 3 wt%.