Splitting axially heterogeneous modes in microwave gyromagnetic and gyroelectric resonators

Theory of calculating eigenmodes spectrum for gyrotropic resonators when using scalar potentials formalism is developed. Equations for calculating splitting of resonant frequencies of gyromagnetic and gyroelectric cylinder resonators in magnetic field are derived. Theoretical results are compared to the experimentally obtained figures for microwave gyromagnetic resonators made of barium hexaferrite. Example of a resonator made of indium antimonide demonstrates the possibility of using magnetized semiconductor resonators cooled to liquid nitrogen temperature to achieve the same characteristics offered by resonators made of magnetically firm hexaferrites when designing unidirectional microwave devices.     

Design of conduction band structure of TiO2 electrode using Nb doping for highly efficient dye‐sensitized solar cells

A barrier layer of undoped TiO₂ was deposited on the Nb‐doped TiO₂ electrode to suppress the recombination at the Nb‐doped TiO₂/dye–electrolyte interface for highly efficient dye‐sensitized solar cells (DSCs). The Nb content in TiO₂ was varied in a range of 0.7–3.5 mol% to modify the TiO₂ energy‐band structure. Nb‐doped TiO₂/dye interfaces were characterized by a combination of ultraviolet photoemission spectroscopy and optical absorption spectroscopy measurements, allowing the determination of the conduction band minimum (CBM) of the TiO₂ electrode and the lowest unoccupied molecular orbital of the N719 dye. The lowering of TiO₂ CBM by Nb doping induced the increase in short‐circuit current of DSCs. However, open‐circuit voltage and fill factor are decreased, and this result was ascribed to the enhanced recombination at the Nb‐doped TiO₂/dye–electrolyte interface. The effect of doping on charge transport in DSCs was analyzed using electrochemical impedance spectroscopy. We have shown that by introducing of TiO₂ barrier layer, the Nb doping content, which results in DSC highest efficiency, can be increased because of the suppression of the dopant‐induced recombination. The energy conversion efficiency of the solar cells increased from 7.8% to 9.0% when undoped TiO₂ electrode is replaced with electrode doped with 2.7 mol% of Nb because of the improvement of the electron injection and collection efficiencies. The correlation between the electronic structure of the TiO₂ electrode, charge transfer characteristics, and photovoltaic parameters of DSCs is discussed. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of soil properties on the seismic damage assessment of historical masonry minaret–soil interaction systems

The interaction between soil and structure plays a crucial role on accurate determination of structures' seismic behavior. The assumption of fixed base structure has been commonly used in traditional design works, and the interaction between soil and structure is thus often neglected. In addition, historical masonry structures particularly built on elastic soil media may be significantly affected seismic behavior of the structure under earthquakes. In this research, the damage distribution on a historical masonry minaret is numerically investigated under horizontal earthquake ground motion. Alaca Mosque minaret was built in 1271 in Bolvadin district of Afyon province. The historical masonry minaret was chosen as the subject of the study. Nonlinear seismic time history analyses were conducted for fixed‐based and different soil properties under horizontal earthquake ground motion. The horizontal (East–West) component acceleration records of Dinar earthquake (Mw = 6.1) that took place on October 10, 1995, were used during the analyses. Maximum displacement, maximum/minimum principal stresses, and damage ratios were determined by nonlinear analyses performed considering fixed base and soil–structure interaction. The analysis results showed that soil–structure interaction had significant effect on the structural behavior of the minaret, such that, the minaret that was expected to get damage in the case of fixed base did not get any damage when soil–structure interaction was considered.     

Impact of irrigation water quality and envelope materials around drip line on emitter performance in subsurface drip irrigation

A field experiment was conducted to study the effect of water quality types of fresh water (FW) and treated wastewater (TWW) and envelope materials of coarse sand (CS), fine sand (FS), and control (CO) on emitter performance, dry matter yield (DMY), and water use efficiency (WUE) under subsurface drip irrigation.The main interaction effect of water quality type and envelope material on coefficient of variation, Christiansen uniformity coefficient, and emission uniformity was not significant (P < 0.05), but they have a significant effect on the average emitter discharge (Q_avg), DMY, and WUE. The means of Q_avg for FW with CS, FS, and CO were 7.13, 6.94, 2.65 L/h, and for TWW, they were 6.78, 6.84, and 2.35 L/h, respectively. The DMY under FW with CS, FS, and CO was 3083.87, 1367.95, and 417.45 kg/ha, and under the TWW, it was 2409.5, 1347.4, and 417 kg/ha, respectively.     

Influence of storage,brine concentration and in‐container heat treatment on the stability of white brined Nabulsi cheese

Microbial levels were significantly (P < 0.05) affected by the temperature‐time treatments used during in‐container heat treatment of the curd, brine concentration and storage duration. A heat treatment of 115 °C × 2 min, in the absence of NaCl, was sufficient to eliminate Mesophilic micro‐organisms, Coliforms, Staphylococcus aureus and Yeast and Moulds for the duration of 1 year of storage. Sensory scores for colour, appearance and texture increased significantly (P < 0.05) with the increase in the NaCl in brine concentration regardless of the temperature‐time treatment.     

Effect of Magnetostatic Dipoles Interaction on the Initial Susceptibility of a Dilute Ferrofluid in One Dimension

The magnetization and the initial susceptibility have been calculated for a one-dimensional linear chain structured dilute ferrofluid considering nearest neighbor magnetic interaction for N-particles. The initial susceptibility is calculated as a function of the orientation angle between the field and the chain direction. Our results predict Curie–Weiss behavior for a one-dimensional magnetic fluid, and showed that the ordering temperature T ₀ depends on the particles separation in a very complicated way. This more general case of calculation reduces to simple results found by the Dimer and Trimer models when N equals 2 and 3, respectively.