Design of dual‐band microstrip patch antenna with right‐angle triangular aperture slot for energy transfer application

This work focusing on the dual‐band antenna design with rectifying circuit for energy transfer system technology for enhancement gain performance. The air gap technique is applied on this microstrip antenna design work to enhance the antenna gain. The work begins with designing and analyzing the antenna via the CST Microwave Studio software. After validation on acceptable performance in simulation side is obtained, the return loss, S₁₁ of the antenna is measured using vector network analyzer equipment. The rectifier circuit is used to convert the captured signal to DC voltage. This projected dual‐band antenna has successfully accomplished the target on return loss of ?44.707 dB and ?32.163 dB at dual resonant frequencies for 1.8 GHz and 2.4 GHz, respectively. This proposed antenna design benefits in low cost fabrication and has achieved high gain of 6.31 dBi and 7.82 dBi for dual‐band functioning frequencies.     

A review of the effects of catalyst and additive on biodiesel production, performance, combustion and emission characteristics

This article is a literature review of the effect of different catalysts and additives on biodiesel production, performance, combustion and emission characteristics. This study is based on the reports of about 60 scientists who published their findings between 1998 and 2010. It was reported that base catalyst produced more biodiesel compared to acid type catalysts. There was not much variation in engine performance with the use of catalyst. Combustion characteristics were improved with the use of additives. It was found that ignition delay was reduced and premixed combustion duration was increased with the addition of catalyst. HC emission and PM emission were reduced with the use of catalysts.     

Hall current impacts on unsteady MHD free convective flow past an infinite vertical porous surface

In this paper, the magnetohydrodynamic free convective flow of an incompressible electrically conducting fluid over a vertical plate embedded in a porous medium is considered. A homogeneous transverse magnetic field is applied in the presence of a heat source and chemical reaction in a rotating frame, taking Hall current effects into account. The momentum equations for the fluid flow in a porous medium were determined by Brinkman modeling. At the undisturbed state, both the plate and fluid have an rigid body rotation due to the constant angular velocity, perpendicular to the infinite vertical plane surface. The vertical surface is subject to the homogeneous constant suction and the heat on the surface vary by time about a nonzero constant rate whereas the temperature of free stream is engaged to be constant. The accurate solutions for the velocity, temperature, and concentration distributions were acquired systematically using the perturbation method. The consequences of an assortment of governing flow parameters on the velocity, temperature, and concentration were analyzed through graphical profiles. The computational results for the skin friction, Nusselt number, and Sherwood number in a tabular format were also examined.     

Supercritical fluid CO<Subscript>2</Subscript>-extraction regeneration of nickel–molybdenum catalyst for hydrotreatment

Results from studying the supercritical fluid СО₂-extraction regeneration of DN-3531 industrial nickel–molybdenum hydrotreatment catalyst in the temperature range of 323.15–383.15 K, at pressures of up to 30 MPa, and with modification of the basic extragent with such polar compounds as chloroform, methanol, ethanol, acetone, and dimethylsulfoxide (DMSO), are presented. The order of modifiers corresponds to the increase in the solubilizing ability of modified supercritical carbon dioxide (SC-СО₂) with respect to catalyst- deactivating deposits. With DMSO as the most efficient modifier, however, not only are deactivating compounds removed but nickel and molybdenum as well, considerably reducing the final activity of a regenerated sample. During extraction regeneration, the content of coke in the catalyst is reduced by two-thirds, while the specific surface area and the pore volume grow. The activity of the deactivated catalyst in dibenzothiophene hydrodesulfurization (HDS) and naphthalene hydrogenation grows by several hundred per cent after one-time SC-CO₂ treatment and is 2.5 times higher than for a sample regenerated using the traditional oxidative method.     

Electrochemical investigation on the corrosion and hydrogen evolution rate of mild steel in sulphuric acid solution

Corrosion and hydrogen evolution rate of mild steel alloy have been investigated using various electrochemical techniques. Mild steel was polarized vs. saturated calomel electrode (SCE) in naturally aerated 0.1 M H₂SO₄ solution containing three newly synthesized heterocyclic compounds in different concentrations. The data obtained from polarization technique showed that the corrosion current density, i_corr, and the hydrogen evolution rate decrease with increasing concentration of heterocyclic inhibitors in 0.1 M H₂SO₄ medium, indicating a decrease in the corrosion rate of mild steel as well as an increase in the inhibition efficiency (IE) of the newly synthesized inhibitors. The impedance measurements confirmed well the polarization behaviour. Increasing the temperature leads to an increase in corrosion or hydrogen evolution rate of the mild steel and a decrease of the total resistance value (R_T) or the relative thickness (1/C_T) of the film. The obtained results were confirmed by surface examination using scanning electron microscope.     

Advances and Applications of Biodegradable Elastomers in Regenerative Medicine

When elastomers were first proposed as useful materials for regenerative medicine a few decades ago, their high versatility and suitability for a diverse and wide range of in vivo applications could not have been predicted. Due to their ability to recover after deformation, these materials were first introduced in tissue engineering in an attempt to mimic the mechanical properties of the extracellular matrix. Furthermore, elastomeric characteristics have been described as important criteria for cell interaction by modulating cellular behavior. From soft to hard tissues, elastomers have demonstrated degradation, mechanical, and biocompatibility requirements in accordance with the target tissue. In this feature article, biodegradable synthetic polyester elastomers that have been reported in the literature are discussed, with special focus on those that show promise for in vivo tissue replacement. Their satisfactory performance in vivo shows the promise of elastomers for use in regenerative medicine. However, further investigation is required to demonstrate the prospect of elastomer‐based therapies in clinical trials.     

Electrochemical behaviour of recasting Ni-Cr and Co-Cr non-precious dental alloys

Corrosion behaviour of dental alloys in artificial saliva was studied using different chemical and electrochemical techniques. The order of corrosion rate for the three alloys in artificial saliva is: wironit < wirolloy < wiron99. This order agrees with the results of chemical studies for determining the cumulative ion concentration using ICP/MS. The open-circuit potential of wirolloy is more positive than wiron99. The higher corrosion rate of wiron99 compared to wirolloy is due to presence of high concentration of Mo. Increasing casting number leads to decrease R_ct value and increasing C_dl.     

Effect of rotation on the heat penetration characteristics of thermally processed tuna in oil in retort pouches

Tuna in oil was processed in retort pouches (20 × 17 cm) to a, F₀ value of 10. Heat penetration characteristics were determined using a rotary retort to an F₀ value of 10 and the results compared with a stationary retort. For studying the changes in heat penetration during rotation, tuna in oil was packed into retort pouches, subjected to different rotation speeds (2, 4 and 6 r.p.m.) and thermally processed to the same F₀ value. For the same F₀ value of 10, although there was a reduction in process time with increasing rotation speed up to 6 r.p.m., the magnitude of the reduction in processing time decreased with increase in speed of rotation. However up to 2 r.p.m. there was a considerable reduction in process time.