High Gain Modified Dual-Band and Dual-Circularly Polarized Array Antenna

Wireless Personal Communications - A novel design of double-layer dual-band circularly polarized array antennas (DDCPAAs) is presented in this paper. First, a DDCP single antenna is introduced as...     

Impedance Studies on Stress Corrosion Cracking Behavior of Steel Pipeline in NS4 Solution under SSRT Test Condition

Protection of Metals and Physical Chemistry of Surfaces - Stress corrosion cracking behavior of API 5L X65 steel in a NS4 solution with different pH was investigated by electrochemical impedance...     

Measurement and Analysis of Laminar Heat Transfer Coefficients in Micro and Mini-Scale Ducts and Channels

Heat transfer in micro- and miniscale ducts and channels is considered. In particular, issues of thermal performance are considered in systems with constant wall temperature at low to moderate Reynolds numbers or small dimensional scales that lead to conditions characteristic of thermally fully developed flows or within the transition region leading to thermally fully developed flows. An analysis of two approaches to representing experimental data is given: one using the traditional Nusselt number, and the other using the dimensionless mean wall flux. Both approaches offer a number of advantages and disadvantages. In particular, it is shown that while good data can be obtained that agree with predicted heat transfer rates, the same data can be problematic if one desires a Nusselt number. Other issues such as boundary conditions pertaining to measuring thermally developing and fully developed flow Nusselt numbers are also discussed in detail.     

Seismic performance of ductile welded connections using T-stiffener

This study presents the development of the ductile detail of a T-stiffener added to existing moment connections. The seismic behavior of the aforementioned detail was investigated analytically as well as experimentally. A new design criterion is developed for a horizontal element of T-stiffener. Results of this study indicate that the crack propagation is eliminated using the new proposed procedure. This means that by utilizing a fillet weld as a replacement for a CJP groove weld in joining the T-stiffener to a beam flange eliminates crack propagation at the tip of the T-stiffener on the beam flange. In the experimental program, the specimens performed well during the test and reached a total story drift angle of 6% radians before experiencing 20% strength degradation.     

Optimization of Circular Ring Microstrip Antenna Using Genetic Algorithm

Circular ring microstrip antennas have several interesting properties that make it attractive in wireless applications. Although several analysis techniques such as cavity model, generalized transmission line model, Fourier-Hankel transform domain and the method of matched asymptotic expansion have been studied by researchers, there is no efficient design tool that has been incorporated with a suitable optimization algorithm. In this paper, the cavity model analysis along with the genetic optimization algorithm is presented for the design of circular ring microstrip antennas. The method studied here is based on the well-known cavity model and the optimization of the dimensions and feed point location of the circular ring antenna is performed via the genetic optimization algorithm, to achieve an acceptable antenna operation around a desired resonance frequency. The antennas designed by this efficient design procedure were realized experimentally, and the results are compared. In addition, these results are also compared to the results obtained by the commercial electromagnetic simulation tool, the FEM based software, HFSS by ANSOFT.     

Microstructure and Optical Bandgap of Cobalt Selenide Nanofilms

Semiconductors - The purpose of this research is to explore the properties of CoSe nanostructured thin films on glass substrates prepared by a chemical solution deposition method. Special attention...     

Strategic signalling and awards: Investigation into the first decade of AIS best publications awards

Professional organizations for academics such as the Academy of Management and Association for Information Systems (AIS) create best publications awards to honour and promote exemplary contributions that align with the core values and priorities of their distinct fields. Despite the strategic importance of awards, researchers rarely investigate meaningful patterns implicit in the contribution characteristics of award-winning articles. We conduct a reconstructive study of the 10-year history of the AIS Best Publications Awards by outlining a framework that reveals contribution characteristics, demographic patterns, and citation histories of the award-winning articles. Comparing the AIS results to a complete sample of MIS Quarterly paper-of-the-year articles (1993–2015) demonstrates consistent patterns implicit in IS articles that win best publications awards. We develop a model that explains both how these awards shape patterns and discusses what changes might be needed as the field confronts new realities. Our analyses reinforce the importance of taking strategic actions to support the continuous development of the field and advance literature on change and evolving trends in academic fields.     

Modified poly(vinyl alcohol)/chitosan blended membranes for isopropanol dehydration via pervaporation: Synthesis optimization and modeling by response surface methodology

Box–Behnken (BB) design of response surface methodology (RSM) was effectively applied to optimize fabrication conditions of modified poly(vinyl alcohol) (PVA) and chitosan (CS) blended pervaporation (PV) membranes. The PVA/CS membranes were crosslinked either by chemical reaction with glutaraldehyde (GA) or by heat‐treating at different temperatures. The main objectives were to determine the optimal levels of fabricating parameters and also to investigate interactions among the variables. CS content in the blended membranes, concentration of crosslinking agent and heat‐treating temperature were the fabrication parameters, the main effects and interaction effects of which on membrane structure and PV performance toward isopropanol (IPA)/water dehydration were investigated, and for which regression models were established. The modified PVA/CS blended membranes were characterized by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) as well as X‐ray diffraction (XRD). It was found that the CS content is the most significant factor influencing flux and separation factor among the three studied variables and the experimental results are in excellent accordance with predicted values from the developed RSM regression models. The RSM results indicated that under preparation conditions of 80 wt % CS in the blended membrane, 0.58 wt % GA concentration, and 77 °C heat‐treating temperature, the maximum separation factor of 5222.8 and the normalized flux of 9.407 kg µm/m²h can be acquired with feed content of 85 wt % IPA at 25 °C, showing that the prepared membrane is highly efficient for PV dehydration of IPA. The models were satisfactorily validated against experimental data. Furthermore, the optimum membrane presents excellent separation performance at different feed compositions and temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44587.