Design of slotted patch antenna based on photonic crystal for wireless communication

Nowadays, the wireless communication is improved in numerous ranges, and the use of the high speed of data rate in the communication systems is needed. The standing problem of high‐performance planar antenna is reduced by the recently developed artificial dielectric called photonic crystal, which is used to control and manipulate the optical property of light. This paper addresses the slotted tube antenna structure, and the investigation is done by the concept of triangular lattice structure based on the photonic crystal. This utility enhances the return loss of ?57.81 dB and the voltage standing wave ratio (VSWR) of 1.002 at 2.37 THz operating frequencies. The increase in hole radius provides the shifting in zero dispersion point towards the shorter wavelength that helps for faster data rate transmission applications. Further, to characterize the model of the proposed antenna, the optimal value of the air hole, lattice constant value between holes and the thickness of the slot are found and the related parameters of such antenna are studied with the support of simulation software CST microwave studio.     

Delineating the effect of substituent and π-bridge flip on the photophysical properties of pyrene derivatives: answers from DFT/TD-DFT calculations

Journal of Materials Science - Pyrene-based Schiff base derivatives have attracted enormous potential as fluorescent probe for multifarious research applications due to their fashionable...     

Substance use among adolescents with juvenile rheumatoid arthritis

BACKGROUND: Delayed graft function is a common and severe complication after cadaveric kidney transplantation. Besides a more complicated postoperative course, DGF can worsen the overall graft survival. In particular, DGF enhances the nephrotoxicity of mainstream immunosuppressants cyclosporine and FK506. This study evaluates a new therapeutical approach to the treatment of DGF related nephrotoxicity, based on the administration of IGF-I. METHODS: Sixty inbred Lewis rats underwent a bilateral clamping of the renal pedicles (20') as standard damage. The animals were stratified in six groups, according to the postoperative treatment. Group 1 served as control and received only the standard ischemic injury. Cyclosporine and FK506 were added in groups 3 and 5. Groups 2, 4 and 6 had the same treatment of groups 1, 3, 5 respectively, plus the administration of IGF-I. Blood samples were drawn daily to evaluate creatinine and BUN for 7 days. RESULTS: The rats treated with IGF-I had significantly better values compared to the respective controls (2-way ANOVA, p < 0.05). CONCLUSIONS: In conclusion, IGF-I improves the nephrotoxicity of mainstream immunosuppressants in this model. Its use is potentially beneficial for transplantation.     

Assessment of shock resistance of barium ferrite at dynamic shocked conditions

Journal of Materials Science: Materials in Electronics - This research work probes into the crystallographic and magnetic structural stability of barium ferrite nanoparticles (BaFe2O4 NPs) at...     

Theoretical and experimental study of the removal of dust particles from flue gases using two-phase steam-water droplet mixtures

The removal of dust particles using two-phase steam-water droplet mixtures has been studied. Two-phase steam-water droplet jets obtained by the flashing expansion of subcooled water, through convergent/divergent nozzles, have been characterized. The water droplet sizes and velocities were measured through the use of stroboscopic photography and laser-doppler velocimetry, respectively. A theoretical model using one-dimensional mass, momentum, and energy balances together with the concept of a critical Weber number criterion was developed to predict water droplet sizes and velocities. The agreement between measurements and predictions was reasonable. A theoretical model for predicting dust collection efficiencies of a two-phase scrubber was developed. It was determined that dust collection efficiencies exceeding 99 pct for basic oxygen furnace flue gases could be obtained using a two-phase scrubber. Formerly a Graduate Student at Massachusetts Institute of Technology     

Energy saving in an air conditioning system using modified HVAC unit as an energy reducer

Nowadays, global warming, environment pollution, and limitations in energy resources have appeared as a serious global crisis. Therefore, energy efficiency and energy conservation are necessary in all energy-consuming devices, such as heating, ventilating, and air conditioning (HVAC) systems. The aims of this project are to evaluate the performance and energy conservation of a conventional air conditioning system and also compare its performance with the proposed HVAC system, which consists of a heat recovery unit to reduce the initial capital cost and electricity consumption of the system. Through hour-by-hour simulations, the annual energy consumptions of these two systems have to be calculated and analysed. A CO₂-based demand controlled ventilation strategy offers a great opportunity to reduce additional energy consumption in the above HVAC systems, while providing the required ventilation.     

Morphological studies of the modified materials: Low-density polyethylene/poly(acrylic acid)/europium(III) and low-density polyethylene/poly(acrylic acid)/uranyl ion

The morphology of low-density polyethylene (LDPE) modified by in situ sorption and thermal polymerization of acrylic acid (AA) in the matrix was examined. The microstructure of the LDPE/poly(acrylic acid) (PAA) materials after Eu³⁺ and UO ion exchange was investigated. The phase behavior of these materials was analyzed using X-ray diffraction, scanning electron microscopy (SEM), and thermal measurements (DSC). The X-ray dif-fraction studies showed that PAA is located at amorphous region of the matrix. The LDPE/PAA surface, as investigate by SEM, was apparently homogeneous before and after Eu³⁺ and UO ion exchange, respectively. Two T_g values were found for the LDPE/PAA material before and after Eu³⁺ ion exchange. Also, three and four T_g values were found for LDPE/PAA after UO ion exchange depending on the amount of UO in the modified matrix. This indicates microphase domains in the LPDE/PAA-, LPDE/PAA/Eu³⁺-, and LPDE/PAA/UO -modified materials, although a lack of visible phase separation in the micrographs was observed. © 1996 John Wiley & Sons, Inc.     

Programmed and Sequential Disassembly of Multi-responsive Supramolecular Protein Nanoassemblies: A Detailed Mechanistic Investigation

The rational design of a multi-responsive protein-based supramolecular system that can predictably respond to more than one stimulus remains an essential but highly challenging goal in biomolecular engineering. Herein, we report a novel chemical method for the construction of multi-responsive supramolecular nanoassemblies using custom-designed facially amphiphilic monodisperse protein-dendron bioconjugates. The macromolecular synthons contain a globular hydrophilic protein domain site-specifically conjugated to photo-responsive hydrophobic benzyl-ether dendrons of different generations through oligo(ethylene glycol) linkers of defined length. The size of the protein nanoassemblies can be systematically tuned by choosing an appropriate dendron or linker of defined length. Exposure of protein nanoassemblies to light results in partial rather than complete disassembly of the complex. The newly formed protein nanoparticle no longer responds to light but could be disassembled into constitutive monomers under acidic conditions or by further treatment with a small molecule. More interestingly, the distribution ratio of the assembled versus disassembled states of protein nanoassemblies after photochemical reaction does not depend on dendron generation, the nature of the linker functionality or the identity of the protein, but is heavily influenced by the linker length. In sum, this work discloses a new chemical method for the rational design of a monodisperse multi-responsive protein-based supramolecular system with exquisite control over the disassembly process.     

Design and analysis of internal cooling passage of gas turbine using computational fluid dynamics

In advanced gas turbines, the turbine blade-operated temperature is above the melting point of blade material. A sophisticated cooling scheme must be developed for continuous safe operation of gas turbines with high performance. This report describes the development and application of a validated computational fluid dynamics (CFD) modelling approach for internal cooling passages in rotating turbomachinery which analyse change in pressure, velocity, temperature, and pressure of fluid in the passage. Velocity changes in the passage help to determine turbulence created in the passage. The CFD analysis is conducted with smooth passage, straight turbulator passage, skewed turbulator passage with different inlet conditions and best model is finalised with high turbulence output. The analysis is carried out using commercial CFD software on k-? model. On evaluating results of different velocity and temperatures, it is found that straight turbulator has more turbulence when compared to smooth and skewed turbulators.

Abbreviations: CFD: computational fluid dynamics; CAD: computer-aided design; k-ε: Eddy-viscosity model