Wideband reflecting frequency-selective surface polarizer for X-band applications

This paper proposed the design of a broadband linear-to-circular reflecting polarizer for X-band applications. The polarizer is designed with three-arm dipole-shaped unit cells with a full ground plane to get wideband performance. The incident linear polarized wave is converted to a right-handed circularly polarized wave upon reflection from the polarizer. The footprint of the unit cell is 9 × 9 mm, which is printed on a FR-4 substrate. Fabricated prototype is measured for its performances like polarization conversion ratio (PCR), fractional bandwidth, and aperture efficiency. The PCR is about 97%, and the fractional bandwidth is 64% with the aperture efficiency of more than 80%. Polarizer performance is analyzed in transverse electric and transverse magnetic modes, and they are stable up to 40° of various incident angles. The polarizer exhibits the 3-dB axial ratio bandwidth from 8 to 12 GHz, which is suitable for satellite applications.     

Multi-response optimization of Nd:YAG laser cutting parameters of Ti-6Al-4V superalloy sheet

Journal of Mechanical Science and Technology - This study proposes a multi-response optimization approach for the Nd: YAG laser cutting parameters of titanium superalloy sheet (Ti-6Al-4V). The...     

Surface modification and characterization of zirconium carbide particulate reinforced C70600 CuNi composite fabricated via friction stir processing

In the present research work, Friction stir processing (FSP) technique has been applied to develop a C70600 graded copper-nickel (CuNi) Surface metal matrix composite (SMMC) reinforced with and without addition of ZrCp. Rotational and traverse speeds were set as 1200 rpm and 30 mm/min, respectively. The fabricated SMMC were metallurgically characterized by using Optical microscope (OM) and Field emission scanning electron microscope (FESEM). The homogeneous distribution of ZrC particles and good interfacial bonding between matrix/reinforcement were observed via OM and FESEM microscopes. The microhardness of the CuNi/ZrC surface composite was observed by using microhardness tester at the cross section of the sample. The average higher microhardness of 148 Hv at CuNi/ZrC SMMC and lower microhardness of 115 Hv at FSPed CuNi was found. The Ultimate tensile strength (UTS) value was measured by using micro tensile testing machine. The UTS value of CuNi/ZrC composite and FSPed CuNi were observed to be 310 MPa and 302 MPa, respectively. The mode of fracture was also observed via FESEM. The X-ray diffraction (XRD) test was carried out to confirm the presence of CuNi & ZrC in the SMMC layer.     

A review on growth optimization of spray pyrolyzed Cu2ZnSnS4 chalcogenide absorber thin film

The progress of solar cell technology in the development of clean and economic quaternary compound copper zinc tin sulfide (CZTS)‐based absorber thin films using the spray pyrolysis technique are presented in this review. CZTS (Cu₂ZnSnS₄) is the only potential competitor for the existing solar thin film absorbing materials owing to its environment‐friendly Earth abundant constituents. Even though different nonvacuum thin film technologies have been developed for the large area fabrication of this nontoxic absorber material, spray pyrolysis technique offers more versatility in changing the process parameters which has a direct impact on the cell efficiency. It can be used for depositing a wide variety of materials even with complex composition with good crystallinity, and the method has the advantage of being flexible and straightforward to design and can be quickly adopted for extensive area deposition. A survey on the effects of experimental conditions as well as the nature of precursors on the structural, morphological, electrical, and optical properties on the spray pyrolyzed CZTS thin films is discussed in detail. This analysis certainly could provide a potential to obtain new insights in the fabrication of high‐efficiency CZTS‐based solar cells and to launch it into the commercial market to satisfy the ever‐growing future energy demand.     

Lipid extraction from natural plant source of Adenanthera pavonina using mixed solvent by superheated extractor

The lipid content was extracted from the saga seed by superheated condition and soxhlet apparatus. The mixture of hexane, chloroform and methanol was utilized as a mixed solvent for these extraction operations. Different parameters such as different solvent, temperature, mean particle size and solvent flow have been examined. The optimized lipid extraction was achieved as 26.2 wt% by using superheated condition from the saga seed powder at 90 °C for 120min. Then the fatty acids profile of the optimized Adenanthera pavonina oil were analyzed by gas chromatography. Unsaturated fatty acid was high as 83.7% compared with saturated fatty acid barely 15.4% by relative.     

Role of ceramic reinforcement in composite polymer electrolyte

Composite polymer electrolytes were prepared from PEO (polyethylene oxide), lithium perchlorate (LiClO₄), and with three different dielectric reinforcements such as lead zirconium titanate (PZT)‐12000, barium titanate (BT)‐1000, and Alumina (Al₂O₃)‐6. Differential scanning calorimetry and X‐ray diffractometry were employed to reveal the crystalline nature of the electrolytes. The conductivity of the composite polymer electrolytes were measured by impedance spectrometry. Among the three systems, PZT reinforced composite exhibits maximum ionic conductivity of 2.9 × 10⁻⁵ S/cm at room temperature. The ionic conductivity of the polymer composites increases with increase in dielectric constant of the reinforcement. The composite with alumina reinforcement displayed strongly modified properties with very weak temperature dependence of conductivity. POLYM. COMPOS., 36:42–46, 2015. © 2014 Society of Plastics Engineers     

Smart utilization of renewable energy sources in a microgrid system integrated with plug‐in hybrid electric vehicles

Mass roll‐out of plug‐in hybrid electric vehicles (PHEVs) and significant penetration of renewable energy sources in distribution system play a major role in delivering low carbon environment. However, placing and utilizing these units randomly result in overloading, increased power loss, and reduced voltage profile. This paper responds to these technical challenges by using a strategic placement method for locating the distributed generation (DG) and the charging station (CS) of PHEVs in a multi‐zone distribution system. For simultaneously scheduling of these units in each zone, the smart energy management framework is proposed in this paper. Apart from usual energy management constraints, this paper also incorporates the real‐time constraints involving the capacity of PHEV batteries, the mobility pattern, and the power level of the charging infrastructure. The simulation studies are carried out for each hour of a day. To cope with this time constraint execution, particle swarm optimization algorithm‐based approach is used. The proposed framework is tested in IEEE 33 and IEEE 69 bus radial distribution system. The obtained results imply that the presented energy management framework provides maximum profits for the vehicle owner, and meanwhile it fulfills preferences of the user in each zone simultaneously.     

A comparison of seven filling to packing switchover methods for injection molding

The effectiveness of seven methods for controlling switchover from the filling to packing stage were investigated, including: (1) screw position, (2) injection time, (3) machine pressure, (4) nozzle pressure, (5) runner pressure near the sprue, (6) cavity pressure near the gate, and (7) cavity temperature at the end of flow. The activation threshold for each of the seven switchover methods was iteratively determined so as to produce similar part weights relative to a standard process. A design of experiments was implemented for each of the seven switchover methods that perturbs the process settings by an amount equal to six standard deviations of the standard process so as to replicate the expected long‐term process variation. The results suggest that conventional switchover methods (e.g., screw position) had lower short‐term variation, but other methods were more robust with respect to rejecting long‐term process variation. The merits of different dimensional measurements for quality control are also discussed relative to the society of the plastics industry (SPI) standard tolerances. POLYM. ENG. SCI., 50:2031–2043, 2010. © 2010 Society of Plastics Engineers     

Aloe vera incorporated biomimetic nanofibrous scaffold: a regenerative approach for skin tissue engineering

Aloe vera (AV) is one of the medicinal herbs with a well-established spectrum of wound healing, antimicrobial and anti-inflammatory property. AV-mediated therapeutics present significant tissue regenerative activity by modulating the inflammatory and proliferative phases of wound healing. The purpose of the present work was to combine the biological properties of AV and the advantages of electrospun meshes to prepare a potent transdermal biomaterial. The polycaprolactone (PCL) containing 5 and 10 wt % of lyophilized powder of AV was studied for electrospinning into nanoscale fiber mats and compared with PCL/Collagen blend for dermal substitutes. SEM revealed the average diameters of PCL, PCL-AV 5 %, PCL-AV 10 % and PCL/Collagen nanofiber scaffolds in the range of 519 ± 28, 264 ± 46, 215 ± 63 and 249 ± 52 nm, respectively. PCL-AV 10 % nanofiber scaffolds showed finer fiber morphology with improved hydrophilic properties and higher tensile strength of 6.28 MPa with a Young’s modulus of 16.11 MPa desirable for skin tissue engineering. The nanofibers were then used to investigate differences in biological responses in terms of proliferation and cell morphology of mice dermal fibroblasts. It was found that PCL-AV 10 % nanofibrous matrix favored cell proliferation compared to other scaffolds which almost increased linearly by (p ≤ 0.01) 17.79 % and (p ≤ 0.01) 21.28 % compared to PCL on sixth and ninth day. CMFDA dye expression, secretion of collagen and F-actin expression were significantly increased in PCL-AV 10 % scaffolds compared to other nanofibrous scaffolds. The obtained results proved that the PCL-AV 10 % nanofibrous scaffold is a potential biomaterial for skin tissue regeneration.     

AGGLO-Hi clustering algorithm for gene expression micro array data using proximity measures

Gene selection is imperative to clustering in light of gene articulation information, as a result of high Clustering quality. Clustering gene articulation information is a vital research subject in bioinformatics on the grounds that knowing which genes act correspondingly can prompt the disclosure of vital natural data. Many clustering systems have been proposed to the examination of gene articulation information got from microarray innovation. Clustering is one of the major procedures of investigating gene articulation information, fundamentally by contrasting gene articulation profiles or test articulation profiles. The Proposed strategy is an Agglo-Hi clustering algorithm which is accounted for the fuse of vicinity similarity estimates like Euclidean Distance, Manhattan Distance Chebyshev Distance, and Cosine Similarity for their execution. The technique is quality articulation information in microarray which is extricated and quality can be chosen from the preprocessed information, at that point the Agglo-Hi Clustering algorithm is utilized for quality information. The grouped information get approved utilizing legitimacy file and the outcome is gotten in light of nearness measures. To refine quality articulation information onto enhanced bunch quality by accelerating Unsupervised Learning stage and the execution of Agglo-Hi algorithm figures the Clustering quality, exactness and time unpredictability.