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In this study, a bi-directional, low-cost, gas metal arc welding (GMAW) based wire arc additive manufacturing (WAAM) setup is used to deposit aerospace-grade super-alloy IN718. The orthogonally designed experiments are carried out to optimize process parameters for bead geometry characteristics. Study result shows that with an increase in heat input, the bead parameters like bead width, reinforcement, dilution, penetration, and weld form factor are increasing, while it has a detrimental effect on weld shape factor and wetting angle. Microstructural examination reveals that at high heat input, coarser grain structure having average grain size of 72.29 µm is obtained while at low heat input, a finer grain structure with average grain size of 32.12 µm along with smaller amount of Laves phases are present. The XRD reveals NbC and TiC phases present in case of low heat input sample which enhances the mechanical properties of deposited material. The multilayer wall structures fabricated at high heat input showed more uniformity in shape with lesser waviness than that fabricated with low heat input. The tensile result of low heat input sample (775.82 MPa) shows higher strength than high heat input sample (741.07 MPa) which is because of smaller grain structure and higher hardness (278.11 HV) as obtained in low heat input sample as compared to high heat input sample (257.26 HV). The EBSD analysis also confirms highly textured surface, more grain boundary lengths and larger grain boundary orientation in low heat input sample imparted better mechanical properties. [ABSTRACT FROM AUTHOR]

Aim: The present study was to investigate the effects of WSE improve cognitive, behavioral and mood disorders in animal models of bipolar disorder. Materials: Animals were divided into six groups each group contain 6 wistar rats of either sex, Behavioral and memory test were carried out followed by estimation of oxidative stress and neurotransmitters in rat brain using continuous sub anesthetic dose of Amph (1.5 mg/kg, i.p) with Withania somnifera extract (300 mg/kg, i.p) and Lithium chloride (100mg/kg, i.p.) administered daily for 21 days. Results: % Alternation was decreased in rat treated with WSE as compared to control indicating that it also improved spatial memory and learning. various oxidative parameters were estimated, oxidative stress was observed the levels of SOD and GSH reduced and increased in TBARS level compared to control groups, but reduced ion in oxidative stress upon administration of Withania somnifera extract and Lithium chloride indicates ameliorating effects of Withania somnifera extract in oxidative stress. Conclusion: We concluded that WSE showed improvement in learning and memory as animals treated with WSE spent more time in open arms as compared to Amphetamine with Withania somnifera and Lithium chloridetreated rats. Overall, the findings of this work show that neurotransmitters get imbalance and change the mood and chemistry of the brain. Hence Withania somnifera extract improve neurotransmitter imbalance which is directly linked with mood, behavior, anxiety and manic episodes in an animal model of bipolar disorder. [ABSTRACT FROM AUTHOR]

In this paper we examined the Withania somnifera extract (WSE) improve cognitive, behavioral and mood disorder in animal model of bipolar disorder. The present study was undertaken to investigate cognitive, behavioral and mood disorder effects of WSE on bipolar disorder of the male/female Wistar albino rats' brain. We have observed after 24 hours of last dosing the behavioral, memory and test were carried out followed by estimation of markers of oxidative stress under six groups using continuous sub-anesthetic dose of Amphetamine (Amph) (1.5 mg/kg, i.p) with WSE (300 mg/kg, i.p) and LiCl (1.5 mEq/kg, i.p.) administered daily for 21 days. We have found the percentage alteration was decreased in rat treated with WSE as compared to control indicate that it also improved spatial memory and learning. We have examined various oxidative parameters such as levels of SOD, GSH and TBARS level as compared to control groups. The reduced level of oxidative stress parameters upon administration of WSE and LiCl indicates ameliorating effects of WSE in oxidative stress. We had concluded that WSE showed improvement in learning and memory as animal treated with WSE spent more time in open arm as compared to Amph with WSE and LiCl treated rats. Hence, we can say that WSE improve cognitive, behavioral and mood disorder in animal model of bipolar disorder. [ABSTRACT FROM AUTHOR]

An ultrawideband (UWB) pentagon shape planar microstrip slot antenna is presented that can find applications in wireless communications. Combination of the pentagon shape slot, feed line and pentagon stub are used to obtain 124% (2.65-11.30 GHz) impedance bandwidth which exceeds the UWB requirement of 110% (3.10-10.60 GHz). A ground plane of 50 mm x 80 mm size is used which is similar to wireless cards for several portable wireless communication devices. The proposed antenna covers only the top 20 mm or 25% of the ground plane length, which leaves enough space for the RF circuitry. Three variations of the antenna design using the straight and rotated feed lines on two different substrates are considered. Effect of the conducting reflecting sheet on back of the antenna is investigated, which can provide directional radiation patterns but with reduced matching criteria. Finally, experimental verification of the fabricated antenna for its impedance bandwidth is carried out, which shows agreement with the simulated data. Index Terms--Directional patterns, finite ground plane, microstrip line feed, microstrip slot antenna, omni-directional patterns, reflecting sheet, ultrawideband (UWB).

A new application for reflector antennas is proposed and developed. Using the aperture theory, a phase center on the reflector aperture is determined and shown that, its location is dependent on the field distribution. The proposed concept is, initially, verified by using a symmetric reflector. It is shown that the phase center is located at the aperture geometric center, when the reflector is illuminated symmetrically about its principal planes. Then, a dual mode feed, employing [TE.sub.11] and [TM.sub.01] modes, is used for generating different reflector illuminations, and causing displacement of its phase center. The concept is then extended to offset reflectors, and the influence of the reflector geometry on the phase center displacement and other reflector electrical parameters is investigated. Based on the established feed radiation pattern requirements, a feed horn is designed using circular waveguide that can propagate both modes. By modifying the amplitude and phase of the modes in the horn, a controlled asymmetric reflector aperture field is achieved. A prototype feed horn is fabricated and tested for its dual mode radiation patterns. The results are in good agreement with simulations. The reflector phase center properties are then investigated, by using the designed feed. A reflector-feed assembly, with its dual phase center capability, was developed for improving the performance of the ground moving target indicator radars. The concept allows the conversion of a single reflector to two or more reflectors, simply by modifying the mode excitation amplitudes and phases, in the feed alone. Index Terms--Beam shift, dual mode, feed horn, ground moving target indicator (GMTI) radar, multiple phase center, reflector antenna.

In this paper, the far-field phase shift properties of microstrip patch antennas are investigated. It is shown that, similar to reflectarrays, the resonant nature of microstrip patches can be used to change the phase of the radiated field. This phase change can be caused by the dimensional change of the microstrip patch, or by a reactive loading of its cavity such as an aperture on its ground plane. However, the available phase shift is limited by the antenna impedance bandwidth. The problem is initially investigated for conventional patch antennas, determining the available phase shift range. It is then studied for a wideband E-slot microstrip antenna, showing a considerably larger phase shift range. Then, a micro-electro-mechanical (MEM) based ground plane membrane, activated by an electrode from below, is proposed to adaptively generate and control the required phase shifts. It provides a low loss, continuously variable phase shifter that can be used at high frequencies for beam scanning in small arrays. Index Terms--Far-field phase shift, frequency tuning, microstrip antenna, microstrip array, phased array.

This paper presents the investigation results on the beam focusing properties of a wire circular monopole array (CMA) antenna consisting of six-elements on a finite ground plane, by exciting more than one monopole at a time. The excitation of more than one element provides enhanced horizontal and vertical plane peak directivities, and a reduced 3 dB beamwidth for the horizontal pattern. The effect of varying the number of monopole elements in the array is also discussed, when only one element is excited, and the remaining ones are shorted to the ground. The antenna was fabricated and tested for its impedance and radiation characteristics for one of the excitation schemes, and the results were found in reasonable agreement with the simulations. Index Terms--Beam focusing properties, circular monopole array (CMA), finite ground, multiple excitations.

Reduced size microstrip monopole slot antennas with different slot shapes--straight, L and inverted T, and placed on a small ground plane, are investigated. The ground plane size is 50 mm x 80 mm, which is about the size of a typical PC Wireless card. Detailed simulation and experimental investigations are conducted to understand their behavior and optimize for broadband operation. It is shown that, the variation in the slot shape, from straight to L and T shapes, helps in generating additional resonances, which when coupled to the original resonances of the slot, further increases impedance bandwidths. The bent shapes of the L and T slots reduce their height and provide more space on the ground plane for electronics. A mirror image dual L-slot antenna, placed at two adjacent corners of the ground plane, is also investigated and optimized for the polarization diversity. They provide an impedance bandwidth of 87%, with near orthogonal radiation characteristics. The measured impedance bandwidths ([S.sub.11] = -10 dB) of up to 60%, 84%, and 80% are achieved for these straight, L and inverted T slots respectively, by suitably selecting their design parameters. The simulation results are in good agreement with the experimental data considering several practical issues. Index Terms--Dual slot antenna, finite ground plane, microstrip line feed, microstrip slot antenna, monopole, polarization diversity, wide bandwidth.

This paper presents the simulation and experimental investigations of a printed microstrip slot antenna. It is a quarter wavelength monopole slot cut in the finite ground plane edge, and fed electromagnetically by a microstrip transmission line. It provides a wide impedance bandwidth adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and location of the slot in the ground plane, and feed and ground plane dimensions. The ground plane is small, 50 mm x 80 mm, and is about the size of a typical PC wireless card. At the center frequency of 3.00 GHz, its width of 50 mm is about [lambda]/2 and influences the slot impedance and bandwidth significantly. An impedance bandwidth ([S.sub.11] = -10 dB) of up to about 60% is achieved by individually optimizing its parameters. The simulation results are confirmed experimentally. A dual complementary slot antenna configuration is also investigated for the polarization diversity. Index Terms--Dual slot antenna, finite ground plane, microstrip line feed, microstrip slot antenna, monopole, polarization diversity, wide bandwidth.