Surface-Wave Losses of Coplanar Transmission Lines

Coplanar transmission lines lose energy to surface waves when the propagation constant of the surface-wave mode exceeds that of the transmission line. This happens when the substrate thickness is an appreciable fraction of a wavelength. The losses should become important in integrated circuits at near-millimeter wavelengths because it is hard to make the substrate thickness small compared to a wavelength. In this paper we have developed a theory based on reciprocity for predicting these losses. We also utilized the quasi-static approximation method to derive expressions for propagation constants and line impedances. Experimental measurements were made for the surface-wave losses in the two strip line, the two slot line and the three wire line, and the results obtained were consistent with the theory

Three-Dimensional Modeling of Wave Propagation over Different Types of Terrains and Environments Using the Parabolic Equation Solved by Higher Order Approximation of the Finite Difference Method

Designing communications and radar systems depends on accurate modeling of ground waves in three-dimensional environment. Propagation of ground waves in the VHF and UHF bands affected by the characteristics of the terrain and the troposphere. Although some three-dimensional modeling of ground waves was found in the literature based on solving the parabolic equation, they were limited to a specific terrain and/or environment. Also, a lot of important factors such as the refractive index of the troposphere were ignored. In this paper, a computational model was developed for predicting the electromagnetic wave propagation over different types of terrains and environments under three-dimensional conditions. The model is based on solving the parabolic equation using higher order approximation of the finite difference method. The model allows specifications of an antenna and the electrical characteristics of the ground. Moreover, the model treats flat and non-flat terrains, mixed path with different electrical characteristics, and forest environment. Furthermore, the model enables calculations to be performed under standard and non-standard refractive conditions of the troposphere that varies in height, width, and range. The results were compared with two-dimensional parabolic equation solved by Fourier split-step and showed excellent agreement

Graphic Design, Symposium Printed Program Contest, Shankar Dayal Dayalan

Art and Design students participated in a graphic design project contest. The winning design was used for the 2020 JSU Student Symposium printed program.https://digitalcommons.jsu.edu/ce_jsustudentsymp_2020/1051/thumbnail.jp

A study on maternal and perinatal outcome of oligohydramnios in term low risk pregnancy

Background: Oligohydramnios is a frequent complication of pregnancy that is associated with increased perinatal morbidity and mortality. Once diagnosed; oligohydramnios should further lead to intensive fetal surveillance including ultrasound evaluation. The aim of the study was to determine obstetric outcome in term low risk pregnancy with AFI less than or equal to 5 and to assess whether antepartum oligohydramnios is associated with adverse perinatal outcome.Methods: 200 patients in third trimester in the hospital with evidence of oligohydramnios (AFI less than or equal to 5) were selected after satisfying inclusion and exclusion criteria and studied prospectively. Observations regarding the outcome of labour in form of maternal and perinatal parameters including AFI value, CTG features, mode of delivery, LSCS rate, meconium stained, APGAR score, birth weight and NICU admission were made.Results: Overall perinatal outcome with respect to CTG, 128 (64%) out of 200 patients had non-reactive CTG and only 72 (36%) had reactive CTG. 128 (64%) of non-reactive CTG delivered by LSCS, 72 (36%) delivered by labour natural. Nil labour natural in the subset of AFI 1 to 2, birth weight (2.5 kg-92%), Apgar score (<7 at 1-5 mins:18%), still birth (1%), meconium (58.5%), NICU admission (6%) and perinatal mortality (2%).Conclusions: AFI measurement of less than 5 cm detected after 37 completed weeks of gestation with a low risk pregnancy is found to be an indicator of adverse pregnancy outcome with higher fetal distress, meconium stained liquor and higher caesarean section rate. AFI assessment serves as an important tool and remains as an effective screening test in predicting fetal distress in labour that requires caesarean section

Aphids: A Model for Polyphenism and Epigenetics

Environmental conditions can alter the form, function, and behavior of organisms over short and long timescales, and even over generations. Aphid females respond to specific environmental cues by transmitting signals that have the effect of altering the development of their offspring. These epigenetic phenomena have positioned aphids as a model for the study of phenotypic plasticity. The molecular basis for this epigenetic inheritance in aphids and how this type of inheritance system could have evolved are still unanswered questions. With the availability of the pea aphid genome sequence, new genomics technologies, and ongoing genomics projects in aphids, these questions can now be addressed. Here, we review epigenetic phenomena in aphids and recent progress toward elucidating the molecular basis of epigenetics in aphids. The discovery of a functional DNA methylation system, functional small RNA system, and expanded set of chromatin modifying genes provides a platform for analyzing these pathways in the context of aphid plasticity. With these tools and further research, aphids are an emerging model system for studying the molecular epigenetics of polyphenisms

cis-Bis(2,2′-bipyridine-κ2 N,N′)dichloridocobalt(II) trihydrate

In the title complex, [CoCl2(C10H8N2)2]·3H2O, the Co(II) ion is situated on a twofold rotation axis and exhibits a slightly distorted octa­hedral geometry and is chelated by four N atoms of the two bidentate 2,2′-bipyridine ligands and two Cl− ions. The crystal packing is stabilized by hydrogen bonding formed between chloride ions and adjacent water mol­ecules. One of the two independent water molecules in the asymmetric unit is disordered over two sets of sites, each on a twofold rotation axis, in a 0.734 (17):0.269 (17) ratio

On the structure differences of short fragments and amino acids in proteins with and without disulfide bonds

Of the 20 standard amino acids, cysteines are the only amino acids that have a reactive sulphur atom, thus enabling two cysteines to form strong covalent bonds known as disulfide bonds. Even though almost all proteins have cysteines, not all of them have disulfide bonds. Disulfide bonds provide structural stability to proteins and hence are an important constraint in determining the structure of a protein. As a result, disulfide bonds are used to study various protein properties, one of them being protein folding. Protein structure prediction is the problem of predicting the three-dimensional structure of a protein from its one-dimensional amino acid sequence. Ab initio methods are a group of methods that attempt to solve this problem from first principles, using only basic physico-chemical properties of proteins. These methods use structure libraries of short amino acid fragments in the process of predicting the structure of a protein. The protein structures from which these structure libraries are created are not classified in any other way apart from being non-redundant. In this thesis, we investigate the structural dissimilarities of short amino acid fragments when occurring in proteins with disulfide bonds and when occurring in those proteins without disulfide bonds. We are interested in this because, as mentioned earlier, the protein structures from which the structure libraries of ab initio methods are created, are not classified in any form. This means that any significant structural difference in amino acids and short fragments when occurring in proteins with and without disulfide bonds would remain unnoticed as these structure libraries have both fragments from proteins with disulfide bonds and without disulfide bonds together. Our investigation of structural dissimilarities of amino acids and short fragments is done in four phases. In phase one, by statistically analysing the phi and psi backbone dihedral angle distributions we show that these fragments have significantly different structures in terms of dihedral angles when occurring in proteins with and without disulfide bonds. In phase two, using directional statistics we investigate how structurally different are the 20 different amino acids and the short fragments when occurring in proteins with and without disulfide bonds. In phase three of our work, we investigate the differences in secondary structure preference of the 20 amino acids in proteins with and without disulfide bonds. In phase four, we further investigate and show that there are significant differences within the same secondary structure region of amino acids when they occur in proteins with and without disulfide bonds. Finally, we present the design and implementation details of a dihedral angle and secondary structure database of short amino acid fragments (DASSD) that is publicly available. Thus, in this thesis we show previously unknown significant structure differences in terms of backbone dihedral angles and secondary structures in amino acids and short fragments when they occur in proteins with and without disulfide bonds