Prediction of hydrate formation conditions to separate carbon dioxide from fuel gas mixture in the presence of various promoters

In this study estimation of hydrate formation conditions to separate carbon dioxide (CO₂) from fuel gas mixture (CO₂+H₂) was investigated in the presence of promoters such as tetra-n-butylammonium bromide (TBAB), tetra-n-butylammonium fluoride (TBAF), and tetra-n-butyl ammonium nitrate (TBANO₃). The emission of CO₂ from the combustion of fuels has been considered as the dominant contributor to global warming and environmental problems. Separation of CO₂ from fuel gas can be an effective factor to prevent many of environmental impacts. Gas hydrate process is a novel method to separate and storage some gasses. In this communication, a feed-forward artificial neural network algorithm has been developed. To develop this algorithm, the experimental data reported in the literature for hydrate formation conditions in the fuel gas system with different concentrations of promoters in aqueous phase have been used. Finally, experimental data compared with estimated data and with calculation of efficiency coefficient, mean squared error, and mean absolute error show that the experimental data and predicted data are in acceptable agreement which demonstrate the reliability of this algorithm as a predictive tool.     

Effects of Extrusion Processing Factors on Reliability of Ceramic Packed Bed Applied for Chemical Contactors

The fracture behaviors of three ceramic categories were studied to achieve the appropriate conditions for manufacturing reliable packed bed employed in liquid–gas contactors. The compression strength of beds was measured by a universal method, and fracture behaviors were characterized by scanning electron microscopy. According to the applied statistical approach results, the reliability of ceramic beds is controlled mainly by the binder type, humidity of paste, particle size distribution of fluxing agents and fillers. Between the studied factors, the roles of composition and humidity are predominant.     

Numerical Investigation on the Impact of DBD Plasma Actuators on Temperature Enhancement in the Channel Flow

The present study indicates the impact of different arrangements of dielectric barrier discharge (DBD) plasma actuators on temperature field in a channel flow. The modified lumped circuit element electro‐static model was used to calculate induced Lorentz body force and plasma dissipation of the actuators. Different distributions of temperature in the modeled channel flow for each arrangement of actuators (one, two, and three attached actuators) are discussed. According to the numerical simulation, DBD plasma actuators are beneficial devices for increasing temperature in the channel flow, especially near the location of the actuators that can be considered for related applications. The actuators are modeled under an incompressible flow regime with low Reynolds number of 335, and the configurations of the actuators are set to be 3 KV for the peak voltage amplitude, 10,000 Hz for the voltage frequency, and Kapton as the dielectric.     

Four coupled parity-time symmetric micro-rings for single-mode laser operation

In this paper, a novel scheme is proposed to obtain the single-mode laser using parity-time symmetry breaking. Four analogue micro-rings are optically coupled in the square configuration in a way that two micro-rings on the square diameter experience gain and the other two experience loss. The coupling coefficient for horizontal and vertical coupling between micro-rings is considered to be different. According to this new scheme, the symmetry of structure is destroyed, and thus the degenerate modes that can disrupt the stability of laser, disappeared. Due to the coupling of the resonators, four super-modes, which are coupled pairwise, are generated. The Eigen-frequency and parity-time symmetry breaking of the two super-modes depend on the difference between horizontal and vertical coupling coefficient; however, these parameters depend on the summation of the coupling coefficients for the other two. Results show that the laser output is single mode in a specific condition of coupling coefficient and gains. It is concluded that the threshold of pump parameter is improved in the new scheme, relative to the two coupled micro-rings.     

Mean interference effects between two buildings: effects of close proximity

This paper presents the mean interference effects between a pair of buildings located in close proximity in a geometrical configuration of L‐ and T‐plan shapes. Experiments are carried out in a closed‐circuit wind tunnel on models of a 1:300 scale to measure the mean pressure distributions on two building models located in close proximity and on models in isolated position over an extended range of wind directions. The mean responses of buildings, namely block 1 and block 2 of L‐ and T‐shaped arrangements subjected to interference effects, are evaluated using the experimentally obtained wind loads and compared it with the responses of a similar building in isolation. Significant changes are observed in the responses of block 1 and block 2 of L‐ and T‐shaped arrangements as compared to a similar building in an isolated position. The interference levels are found to be dependent strongly on the angle of attack and the arrangement of the buildings with respect to each other. At wind incidence angle 0°, the presence of block 1 reduces the mean along the wind displacement of block 2 of the L‐ and T‐shaped arrangements up to 21% and 37%, respectively, as compared to a similar block in an isolated position. Copyright © 2009 John Wiley & Sons, Ltd.     

Software-programmable continuous-flow multi-purpose lab-on-a-chip

Current lab-on-a-chip (LoC) devices are assay-specific and are custom-built for each single experiment. Performing an experiment requires scientists or engineers to go through the time-consuming process of designing, fabricating, and testing a chip before conducting the actual experiment. This prolonged cycle can take months to complete, increasing effort and cost and reducing productivity. Similarly, minor modifications to an assay protocol re-incur the overheads of the design cycle. In this paper, we develop a multi-purpose, software-programmable Lab-on-a-Chip (SPLoC), where the user simply writes or downloads a program for each experiment. We describe the components necessary to realize the SPLoC, which include a high-level programming language, an abstract instruction set, a runtime and control system, and a microfluidic device. We describe two key features of our high-level language compiler, and describe a novel variable-volume variable-ratio mixer. Finally, we demonstrate our SPLoC on four diverse, real-world assays.     

The real cost of air conditioning load

The significance of the air conditioning load and its impact on the daily fuel cost of electric power networks have been pointed out. A model has been developed for assessing the increase in the daily fuel cost due to the A/C load, taking into account both the system load characteristics (peak load, load factor, generation cost) as well as the parameters of the added air conditioning load (A/C peak load, starting time and its duration). The model allows for the consideration of two different control procedures used for reducing the daily cost of the power network's fuel consumption: delaying the A/C load starting time; and the utility-controlled disconnection of the A/C load for several minutes per hour. The simultaneous application of both strategies can be also simulated and economically assessed     

An efficient DEA method for ranking woven fabric defects in textile manufacturing

This paper deals with the problem of ranking woven fabric defects (WFDs) observed in textile manufacturing using a data envelopment analysis (DEA) method. The paper shows that the optimal solutions of DEA models for decision-making units (DMUs) with multiple inputs can be found without the need of solving the corresponding models. The paper performs a mean–variance analysis for determining the most important statistical factors of WFDs in terms of multiple inputs. The paper also ranks the observed WFDs from the worst preferred using the suggested DEA formulation. The contribution of this study can be explained as follows. It introduces a new application for DEA method in textile manufacturing for ranking fabric defects. This is significant in defining rich project in reducing defects through prioritizing of quality specification of fabric defects by Six Sigma experts. Also, the result of this paper can be obtained using an efficient DEA method without the need of solving the corresponding DEA models for any sample size of fabric defects.