A theoretical investigation of noise reduction through the cylindrical fuselage of a twin-engine, propeller-driven aircraft

Interior noise in the fuselage of a twin-engine, propeller-driven aircraft with two propellers rotating in opposite directions is studied analytically. The fuselage was modeled as a stiffened cylindrical shell with simply supported ends, and the effects of stringers and frames were averaged over the shell surface. An approximate mathematical model of the propeller noise excitation was formulated which includes some of the propeller noise characteristics such as sweeping pressure waves around the sidewalls due to propeller rotation and the localized nature of the excitation with the highest levels near the propeller plane. Results are presented in the form of noise reduction, which is the difference between the levels of external and interior noise. The influence of propeller noise characteristics on the noise reduction was studied. The results indicate that the sweep velocity of the excitation around the fuselage sidewalls is critical to noise reduction

Densification and Structural Transitions in Networks that Grow by Node Copying

We introduce a growing network model---the copying model---in which a new node attaches to a randomly selected target node and, in addition, independently to each of the neighbors of the target with copying probability $p$. When $p<\frac{1}{2}$, this algorithm generates sparse networks, in which the average node degree is finite. A power-law degree distribution also arises, with a non-universal exponent whose value is determined by a transcendental equation in $p$. In the sparse regime, the network is "normal", e.g., the relative fluctuations in the number of links are asymptotically negligible. For $p\geq \frac{1}{2}$, the emergent networks are dense (the average degree increases with the number of nodes $N$) and they exhibit intriguing structural behaviors. In particular, the $N$-dependence of the number of $m$-cliques (complete subgraphs of $m$ nodes) undergoes $m-1$ transitions from normal to progressively more anomalous behavior at a $m$-dependent critical values of $p$. Different realizations of the network, which start from the same initial state, exhibit macroscopic fluctuations in the thermodynamic limit---absence of self averaging. When linking to second neighbors of the target node can occur, the number of links asymptotically grows as $N^2$ as $N\to\infty$, so that the network is effectively complete as $N\to \infty$.Comment: 15 pages, 12 figure

Phase separation in transparent liquid-liquid miscibility gap systems

A program to be carried out on transparent liquid-phase miscibility gap materials was developed for the purpose of acquiring additional insight into the separation process occurring in these systems. The transparency feature allows the reaction to be viewed directly through light scattering and holographic methods

Molecular cloning of endochitinase 33 (ECH33) gene from Trichoderma harzanium

This study was conducted to screen for the presence of ech33 gene in 80 isolates of Trichoderma. Furthermore, using gene specific primers, ech33 gene were cloned into pTZ57R/T from T. harzanium IABT1068. The clone was confirmed through PCR amplification and restriction analysis. The  clones were sequenced and analyzed for homology at nucleotide and protein level to find out conserved domain of protein. Gene encoding endochitinase from both species have 96 and 95%  homology with reported sequence both at nucleotide and protein level. The cloned ech33 has a size of 1159 bp, of which 9 bp corresponds to the 5' untranslated region, with a 650 bp open reading frame. The amino acid sequence of gene has signal peptide sequence ranges from 1 to 19. The nucleotide sequence analysis using GENETOOL software revealed presence of three exon and four introns, and has unique restriction sites for HindIII, BamHI and SalI, at 881, 308 and 485 positions, respectively.Key words: Trichoderma harzanium, ech33, signal peptide