1,101 research outputs found
Dependence of chaotic behavior on optical properties and electrostatic effects in double beam torsional Casimir actuation
We investigate the influence of Casimir and electrostatic torques on double
beam torsional microelectromechanical systems with materials covering a broad
range of conductivities of more than three orders of magnitude. For the
frictionless autonomous systems, bifurcation and phase space analysis shows
that there is a significant difference between stable and unstable operating
regimes for equal and unequal applied voltages on both sides of the double
torsional system giving rise to heteroclinic and homoclinic orbits,
respectively. For equal applied voltages, only the position of a symmetric
unstable saddle equilibrium point is dependent on the material optical
properties and electrostatic effects, while in any other case there are stable
and unstable equilibrium points are dependent on both factors. For the
periodically driven system, a Melnikov function approach is used to show the
presence of chaotic motion rendering predictions of whether stiction or stable
actuation will take place over long times impossible. Chaotic behavior
introduces significant risk for stiction, and it is more prominent to occur for
the more conductive systems that experience stronger Casimir forces and
torques. Indeed, when unequal voltages are applied, the sensitive dependence of
chaotic motion on electrostatics is more pronounced for the highest
conductivity systems.Comment: 24 pages, 11 figure
Zero tension Kardar-Parisi-Zhang equation in (d+1)- Dimensions
The joint probability distribution function (PDF) of the height and its
gradients is derived for a zero tension -dimensional Kardar-Parisi-Zhang
(KPZ) equation. It is proved that the height`s PDF of zero tension KPZ equation
shows lack of positivity after a finite time . The properties of zero
tension KPZ equation and its differences with the case that it possess an
infinitesimal surface tension is discussed. Also potential relation between the
time scale and the singularity time scale of the KPZ
equation with an infinitesimal surface tension is investigated.Comment: 18 pages, 8 figure
Application of Efficient Express Sequence Tags Information for Classification and Functional Study of Simple Sequence Repeats in Cattle Testis Tissue
Genomic markers play an important role in tracing the flow of genetic causality of observable signals in animals and plants. In farm animals, the participation of male animals in the gene pool of subsequent generations are much higher than female animals and testes are the most important organs of the male reproductive system. This study was conducted to investigate simple sequence repeats (SSR) within the expressed sequence tags (ESTs) in order to classify the Bos taurus testis tissue’s genes for their relationship and specificity with related reproductive domains. A total of 48,549 publicly available EST sequences from cattle testis tissue downloaded from GenBank database, out of which, 10,237 sequences that their library made from testis tissue were extracted and specialized as the studied sequences using several searching tools and software. Across these selective sequences, 2,039 contigs, 5,097 singletons, and 153 SSRs were detected. EST-SSRs were subsequently evaluated using GenBank and categorized based on their functions in biological systems of dairy cattle. Investigation of these motifs showed that the identified EST-SSRs can be classified into 48 types that GT in dinucleotides and GCC in trinucleotides had the highest frequency. Annotation and gene ontology analysis revealed a relationship among 54 domains with the observed SSRs. Localization and characterization of such markers can help tracing the production of amino acids coded by identified repeats as shown in this study
Spectroscopic Study of some Schiff Bases Derived from Dibenzoylmethane
A series of Schiff bases 7-11 derived from dibenzoylmethane have been prepared. The UV, IR, 1H NMR and mass spectra revealed theses compounds were existed mainly as the keto-enamine tautomer in the solution. The absorption bands which appeared in the range λmax = 376-406 nm were assigned to the electronic transitions which arised from the central hydrogen bonded chelated unsaturated ring system in this tautomer. The appearance of the broad singlet near d  = 13 ppm due to the N-H proton and a singlet near d  = 6 ppm due to the –C=C-H proton inaddition to benzoyl fragment ion     signal m/z =105 in the mass spectra supported the above suggested products
Derivati aminokiselina. Dio 1. Sinteza, antivirusno i antitumorsko djelovanje novih estera alfa-aminokiselina s kumarinskim supstituentom
A series of amino acid esters bearing coumarin (3-15) were synthesized and evaluated, in vitro, against HIV-1, and bovine viral diarrhea virus (BVDV). The in vitro cytotoxicity of 3-10 and 12 were assyed against a panel of tumor cell lines consisting of CD4 human T-cells. Compound 14 showed inhibition of HIV-1 with EC50 > 1.6 microg mL-1, meanewhile compound 9 exhibited activity against leukaemia (MT4) with CC50 = 24 micromol L-1).U radu je opisana sinteza estera aminokiselina s kumarinskim ostatkom 3-15. Ispitano je antivirusno djelovanje sintetiziranih spojeva na HIV-1 i goveđi virus diareje (BVDV) te in vitro citotoksičnost spojeva 3-10 i 12 na tumorskim linijama CD4 humanih T-stanica. Spoj 14 pokazao je inhibiciju HIV-1 s EC50 > 1.6 microg mL-1, dok je spoj 9 djelotvoran na leukemiju (MT4) s CC50 = 24 micromol L-1
Level Crossing Analysis of Burgers Equation in 1+1 Dimensions
We investigate the average frequency of positive slope ,
crossing the velocity field in the Burgers equation.
The level crossing analysis in the inviscid limit and total number of positive
crossing of velocity field before creation of singularities are given. The main
goal of this paper is to show that this quantity, , is a good
measure for the fluctuations of velocity fields in the Burgers turbulence.Comment: 5 pages, 3 figure
Avrami behavior of magnetite nanoparticles formation in co-precipitation process
In this work, magnetite nanoparticles (mean particle size about 20 nm) were synthesized via coprecipitation method. In order to investigate the kinetics of nanoparticle formation, variation in the amount of reactants within the process was measured using pH-meter and atomic absorption spectroscopy (AAS) instruments. Results show that nanoparticle formation behavior can be described by Avrami equations. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were performed to study the chemical and morphological characterization of nanoparticles. Some simplifying assumptions were employed for estimating the nucleation and growth rate of magnetite nanoparticles
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