COMPARATIVE ANALYSIS OF MODULATION SCHEMES USING ADAPTIVE EQUALIZATION AS FADING MITIGATION TECHNIQUE

Inter-symbol interference (ISI) due to multipath fading is a vital problem in high-speed wireless communication which restricts communication quality and capacity. Therefore, in addition to choosing a fading mitigation technique, it is also important to strategically select a modulation scheme for effective data transmission. Recent literature review on wireless standards, such as 3G and 4G indicates that QAM and QPSK are suitable choices for data transmission. In this paper, a comparative analysis on selected modulation schemes is performed in a fading environment. The mitigation of fading is done using adaptive equalization technique. Also, we show that the signal to noise ratio (SNR) is an important parameter to choose. It is observed that, even when an adaptive equalizer is used at the receiver, a very low SNR gives very high symbol error rate (SER). We derive some important conclusions from our simulation result: QPSK shows minimum SER, whereas 256-PSK and 256-PAM perform worse. Given its spectral efficiency and a low SER, the best choice is 256- QAM

High frequency <i>in vitro </i>propagation of <i>Phyllanthus amarus </i>Schum. &Thom. <span style="font-size:14.0pt;line-height:115%;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";color:black;mso-ansi-language:EN-IN; mso-fareast-language:EN-IN;mso-bidi-language:HI" lang="EN-IN">by shoot tip culture</span>

1184-1187With the aim of micropropagation of Phyllanthus amarus , an important medicinal herb, shoot tips were cultured in Murashige and Skoog's medium supplemented with kinetin/ BAP singly or in combination with IAA. Growth regulators at lower range (0.1- 1.0 mg L-1) stimulated direct regeneration of shoots. Kinetin was superior to BAP and kinetin-IAA combination was more suitable than kinetin alone. About 15 shoots were yielded per explant after 30 days of culture in the medium containing kinetin and IAA both at 0.1 mg L-1 &nbsp;The cluster of proliferated shoots elongated and rooted simultaneously under the same treatment following another subculture, thus shortening the total time schedule of micropropagation. Shoot tips of regenerated shoots were continuously used to regenerate new shoots with periodic transfer to fresh medium resulting in a steady supply of normal, healthy plants without any deviation in the production rate during a continuous one year culture. Micropropagated plants were successfully established in soil with high survivality (80%).</span

Fatigue failure of a boiler feed pump rotor shaft

This paper deals with a detailed failure investigation of a rotor shaft in a boiler feed pump of a thermal power plant. The investigation mainly included chemical analysis, microscopy, fractography, hardness measurement and residual stress measurement. Analysis revealed that the metallization processes was primarily responsible for the failure. There were a large number of defects at the interface where the metallization process was terminated near the fillet. The crack had initiated from one or more such defect areas and then further propagated by fatigue. The mode of fracture was fatigue and the presence of oxides at the base of the cavities at the interface regions indicated that surface preparation was not made properly prior to metallization

Investigation of sub-surface cracks in continuous cast billets

Sub-surface cracks in the continuous cast product of steel were studied to understand the causes of such defects and to suggest remedial measures. Even after hot rolling the cracks were not welded. The diameter of the as cast billets were 225 mm and most of the cracks were located around l cm away from the edges. The cracks were visible with the naked eye at transverse sections. The cracks were not continuous but scattered. The objective of this work was to identify the root cause of the formation of the sub-surface defects on the concast product and to ascertain whether it was due to any material related problem or due to any other cause such as processing. The existing cracks were opened through mechanical testing. The fracture surfaces were observed by SEM. Metallography and SEM observations revealed that the cracks were generated due to preferential segregation of sulphur, Cu and subsequent formation of various types of sulphide inclusions. The presence of a higher amount of Cu, particularly in the cracked region is of great concern. Cu is very harmful in steel if it exceeds the tolerable limit, particularly with the presence of high amount of S. The sulphide inclusions are found at the existing cracked regions. Inclusions at the crack is indicative of a correlation between inclusions and cracks. The inclusions act as a second phase and may influence the solidification of the matrix by restriction in directional solidification, differential contraction and even acting as a source of stress concentration—hence the appearance of cracks. The location-specific segregation of the inclusions is however surprising. Had there been dispersion of inclusions, probably the cracks would not have resulted

Hymenopteran parasitoid complex and fall armyworm: a case study in eastern India

Abstract Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) has significantly affected maize crop yields, production efficiency, and farmers’ incomes in the Indian Eastern Gangetic Plains region since it was first observed in India in 2018. A lack of awareness by maize growers of the appropriate selection, method, and timing of insecticide application not only creates a barrier to sustainable FAW control but also contributes to increased environmental pollution, reduced human health and increased production costs. We demonstrated that FAW inflicted the most damage in early whorl growth stage of maize, regardless of whether chemical insecticides were applied. FAW egg masses and larvae collected from maize fields in which no insecticides had been sprayed showed high parasitism rates by parasitoid wasps; in contrast fields that had been sprayed had much lower rates of parasitism on FAW. Ten hymenopteran parasitoids were observed in maize fields across the study region, suggesting a diversity of natural methods to suppress FAW in maize at different growth stages. These included two FAW egg parasitoids and eight FAW larval parasitoids. Microplitis manilae Ashmead was the most abundant FAW larval parasitoid species, and Telenomus cf. remus was the dominant FAW egg parasitoid species. Endemic FAW parasitoids such as those observed in this study have great potential as part of a sustainable, cost-effective agroecological management strategy, which can be integrated with other methods to achieve effective control of FAW