Tuning of Constant in gain Lead in phase (CgLp) Reset Controller using higher-order sinusoidal input describing function (HOSIDF)

Due to development of technology, linear controllers cannot satisfy requirements of high-tech industry. One solution is using nonlinear controllers such as reset elements to overcome this big barrier. In literature, the Constant in gain Lead in phase (CgLp) compensator is a novel reset element developed to overcome the inherent linear controller limitations. However, a tuning guideline for these controllers has not been proposed so far. In this paper, a recently developed method named higher-order sinusoidal input describing function (HOSIDF), which gives deeper insight into the frequency behaviour of non-linear controllers compared to sinusoidal input describing function (DF), is used to obtain a straight-forward tuning method for CgLp compensators. In this respect, comparative analyses on tracking performance of these compensators are carried out. Based on these analyses, tuning guidelines for CgLp compensators are developed and validated on a high-tech precision positioning stage. The results show the effectiveness of the developed tuning method

Suppression of Octahedral Tilts and Associated Changes of Electronic Properties at Epitaxial Oxide Heterostructure Interfaces

Epitaxial oxide interfaces with broken translational symmetry have emerged as a central paradigm behind the novel behaviors of oxide superlattices. Here, we use scanning transmission electron microscopy to demonstrate a direct, quantitative unit-cell-by-unit-cell mapping of lattice parameters and oxygen octahedral rotations across the BiFeO3-La0.7Sr0.3MnO3 interface to elucidate how the change of crystal symmetry is accommodated. Combined with low-loss electron energy loss spectroscopy imaging, we demonstrate a mesoscopic antiferrodistortive phase transition and elucidate associated changes in electronic properties in a thin layer directly adjacent to the interface

Caesarean myomectomy in a patient with multiple maternal and fetal comorbidities: a rare interesting case report

Caesarean myomectomy has been traditionally discouraged due to the fear of complications like intractable haemorrhage, peripartum hysterectomy, and increased postoperative morbidity. Recently, a number of authors in their studies have shown that myomectomy during caesarean section does not increase the risk of haemorrhage or postoperative morbidity, if adequate haemostatic methods are used and done by skilled surgical hands. Caesarean myomectomy was performed in a case of elderly primigravida with 36-week gestation with chronic hypertension with polyhydramnios with anterior wall pedunculated fibroid of 8.6×7.2×8 cm and multiple small fibroids in the anterior wall, fundus and subserosal plane. Caesarean myomectomy is a safe and effective procedure in a tertiary care centre at hands of an experienced surgeon

Didelphys uterus: an interesting case report of pregnancy in a rare Mullerian anomaly

Mullerian duct anomalies (MDAs) are congenital defects of the female genital system that arise from abnormal embryological development of the Mullerian ducts. A didelphys uterus, also known as a double uterus, is one of the least common amongst the MDAs. This report discussed a case of pregnancy with uterus didelphys. This patient was a 27-year-old primigravida with 34.2-week gestation with spontaneous conception who presented with decreased fetal movements. On examination patient had a non-communicating, thick vaginal septum extending from the introitus to the cervix was seen and two cervices one on each side of the septum were located. The patient underwent emergency lower segment caesarean section in view of foetal distress and doppler changes. Intra-operatively, evidence of didelphys uteri was seen. Intraoperative and post-operative period was uneventful. A fetus of 1790 gram was delivered, with APGAR 9/10. There were no renal anomalies on subsequent ultrasonography

Editorial : Energy and environment : challenges and achievements in rapid urbanization

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Evaluation of antibacterial and antifungal activity of root and root callus extracts of Trianthema decandra L.

Trianthema decandra L. root and root callus extracts of different solvents viz.,petroleum ether, chloroform, ethyl acetate and ethanol were tested against both Gram positive and Gram negative bacteria and also against Fusarium spp. Root callus extract of chloroform and ethanol showed significant activity against Bacillus subtilis, B. cereus. Staphylococcus aureus, Staph. epidermis and also against the other spp. of Gram negative bacteria viz., Pseudomonas aeruginosa, Klebseilla pneumonia, Alcaligens faecalis, Proteus vulgaris Enterobacter aerogenes,Salmonella typhi, Salmonella tyhimurium, Salmonella paratyphi A and Salmonella enterica subsp. enterica with a MIC of 3.12 to 12.50 μg/ml when compared to root extract of chloroform, ethyl acetate and ethanol of Trianthema decandra. Root callus extract of chloroform, ethyl acetate and ethanol showed activity against Fusarium verticilliodes, F. anthophilum, F. oxysporum and F. proliferatum with a lowest MIC of 3.12 μg/ml when compared to root extract of Trianthema decandra. The result showsthat antibacterial and antifungal activity was more in root callus extract than root extract

Design and Development of Mechanical Solar Tracking System

In recent years, the growing global interest in the conservation of environment has provided a fresh motivation for research in the area of solar energy utilization. Already, installation of solar energy extraction devices such as solar panels, solar water heaters, solar cookers etc. is becoming popular in urban buildings. Most of these devices consist of a solar receptor that is kept facing the sun during the day, but the sun moves from east to west and the efficiency of the panel decreases. If one could trap this extra energy source then the efficiency of the solar panel would be increased. A tracking mechanism following the sun would achieve this aim. An attempt has been made to develop a simple yet efficient sun tracking mechanism using a motor, a speed reduction mechanism and real timer. The mechanism has been designed such that the sunrays falling on the panel are always perpendicular to the panel resulting in increase in efficiency of the electricity generation. This report presents, in detail, the design and construction adopted to develop the functional model that was fabricated and tested for performance which yielded the efficiency increase of 28.41% as compared to the conventional stationary panel position

Pore Elimination Mechanisms during 3D Printing of Metals

Laser powder bed fusion (LPBF) is a 3D printing technology that can print metal parts with complex geometries without the design constraints of traditional manufacturing routes. However, the parts printed by LPBF normally contain many more pores than those made by conventional methods, which severely deteriorates their properties. Here, by combining in-situ high-speed high-resolution synchrotron x-ray imaging experiments and multi-physics modeling, we unveil the dynamics and mechanisms of pore motion and elimination in the LPBF process. We find that the high thermocapillary force, induced by the high temperature gradient in the laser interaction region, can rapidly eliminate pores from the melt pool during the LPBF process. The thermocapillary force driven pore elimination mechanism revealed here may guide the development of 3D printing approaches to achieve pore-free 3D printing of metals