A New Compact Microstrip Integrated E-Array Patch Antenna with High Gain and High Aperture Efficiency

This paper describes a new compact single-feed, single-layer microstrip E-shaped patch antenna. It is an integrated array antenna and it is designed for a frequency range around 2.45 GHz ISM band. It is a symmetrical antenna suitably designed for WLAN application. This prototype was fabricated on a FR4 substrate with a relative permittivity of 4.7 and about 0.8 mm thickness. The aperture efficiency and gain of about 72 % and 6.7 dBi was obtained. It can be achieved by numerical algorithms for electromagnetic solutions like finite element method (FEM) and the method of moments (MOM) by using electromagnetic simulation software. For validation purpose CAD FEKO 6.1 suite is used. The bandwidth and gain achieved in the array antenna is 15 % greater than the single patch antenna.     

Direct Catalytic Conversion of Ethanol to C5+ Ketones: Role of Pd–Zn Alloy on Catalytic Activity and Stability

Ethanol can be used as a platform molecule for synthesizing valuable chemicals and fuel precursors. Direct synthesis of C₅₊ ketones, building blocks for lubricants and hydrocarbon fuels, from ethanol was achieved over a stable Pd‐promoted ZnO‐ZrO₂ catalyst. The sequence of reaction steps involved in the C₅₊ ketone formation from ethanol was determined. The key reaction steps were found to be the in situ generation of the acetone intermediate and the cross‐aldol condensation between the reaction intermediates acetaldehyde and acetone. The formation of a Pd–Zn alloy in situ was identified to be the critical factor in maintaining high yield to the C₅₊ ketones and the stability of the catalyst. A yield of >70 % to C₅₊ ketones was achieved over a 0.1 % Pd‐ZnO‐ZrO₂ mixed oxide catalyst, and the catalyst was demonstrated to be stable beyond 2000 hours on stream without any catalyst deactivation.     

Tandem Favorskii Intermediate/Cyclization Leading to Tricyclo[4.4.0.0]decanediones

The mechanism of dehydrobromination of the bromodiketone 8 leading to the unusual ring system of tricyclo[4.4.0.0]decanediones (9 and 10) is described. An entry into the ring system of the sesquiterpenoid hydrocarbons copaene and ylangene, 8 to 9, is achieved in three steps starting with enone 6. Compound 9 was either derived from a direct internal S_N2 cyclization of 8 or the Favorskii intermediate 8a. Formation of compound 10, on the other hand, can only occur via the Favorskii intermediate 8a. Structure assignments of 9 and 10 were determined using both one‐ and two‐dimensional NMR experiments.     

Comparisons Between Numerical Model and Experiments for a Direct Current Plasma Flow

The governing equations describing a flowing stream of a hydrogen plasma encountered in applications, such as diamond deposition, and in devices, such as arcjet thrusters, are solved numerically using the linearized implicit (LBI) Method of Briley and McDonald. The results of simulations under the assumption that the plasma can be described by a single temperature are compared with detailed experimental measurements of flow characteristics and species concentrations in a 1 kW arcjet. These comparisons show that by formulating the problem in terms of known experimental operating conditions, such as mass flow rate, power, and current levels, it is possible to predict many of the characteristics of the flowing plasma. As expected, predictions from this one-temperature model show that some deviations from the experimental results occur near the exit plane of the channel, where unequal electron and heavy particle temperatures are encountered because of lower pressures.     

The benefits of wavelength conversion in WDM networks withnon-Poisson traffic

The effects of wavelength conversion on wavelength routing optical networks with dynamic non-Poisson traffic are investigated. A model that characterizes any non-Poisson traffic by its first two moments is utilized. The arrival occupancy distribution of busy wavelengths for this model process is derived and is used to analyze the effects of wavelength conversion. The model predicts that traffic peakedness plays an important role in determining the blocking performance     

Two-level QoS-aware frame-based downlink resources allocation for RT/NRT services fairness in LTE networks

In LTE, bandwidth resources allocation became a huge burden to be handled, as both of RT and NRT traffic should be processed fairly to satisfy their diverse QoS requirements. To tackle this issue in particular, in this work, we propose a fairness-based resources allocation method named Frame-based Game Theory (FGT), which can be flexibly implemented as an upper level in LTE downlink MAC layer; before the PRBs allocation function. Basically, FGT aim is to allow involved classes with different QoS requirements to fairly gain a part of the available channel resources to transmit their flows. Adhere, on every LTE-frame, a cooperative game scenario is designed. Wherein, Shapley formula is used to distribute the available amount of data within RT and NRT traffic classes. Then, conforming to these assigned resources portions to each traffic class, PRBs allocation process is triggered every TTI for the selected flows. In this work, we adopted some of the recent PRBs allocation methods as a lower level scheduler in order to illustrate a complete idea of MAC layer scheduling functions, and also to effectively evaluate FGT performance. Simulation results on various scenarios show that, fairness index for flows from different classes is increased when FGT is considered. The results also conveyed outperforming QoS indices for FGT on RT and NRT service in terms of throughput, PLR, as well as cell spectrum efficiency.