Order-N Formulation and Dynamics of Multi-Unit Flexible Space Manipulators

As robotic manipulators gain more importance in space operations, it is becoming imperative to understand their distinctive dynamics and control characteristics. With the increasing complexity of space robots, efficient algorithms are now required for their simulation. The present study uses an order-N algorithm, based on the Lagrangian approach and velocity transformations, to simulate the planar dynamics of a novel orbiting manipulator with arbitrary number of slewing and deployable flexible links. The relatively general formulation accounts for interactions between orbital, librational, slewing, deployment, and vibrational degrees of freedom, and thus is applicable to a large class of manipulator systems of contemporary interest. A parametric analysis of the system dynamics is carried out to investigate the effects of initial disturbances, variation of system parameters and maneuver profiles. The study suggests significant coupling between the rigid body motion and structural vibrations. As a result, the system's flexibility can significantly affect the manipulator's performance.     

Forced response of neutrally buoyant inflated viscoelastic cantilevers to ocean waves

The dynamics of the neutrally buoyant inflated viscoelastic cantilevers constituting a submarine detection system is investigated. Thin shell theory is used to account for the stresses arising due to the internal pressure. A significant feature of the analysis is the use of the reduced shell equation which is similar in form to that for a vibrating beam with rotary effects. The forcing function in the form of surface wave excitation consists of a fundamental frequency and its second harmonic. Both the effects of apparent inertia and viscous drag are accounted for. The highly complicated non-linear, coupled equations are analyzed numerically. Use of the reduced form of the shell equations appears to avoid the problems of numerical instability and convergence reported by several investigators. The amount of information generated is rather enormous; however, for conciseness, only a few of the typical data, sufficient to establish trends, are presented. The results suggest that for the case of simple harmonicexcitation, the non-linear hydrodynamic drag introduces no superharmonic components into the response. The analysis provides valuable information concerning the system parameters leading to critical response and hence should prove useful in the design of inflatable structural members.     

Determination of mycophenolic acid in human plasma by high-performance liquid chromatography

The development, validation and evaluation of high-performance liquid chromatography (HPLC) method for quantifying mycophenolic acid in human plasma is described. The method involved protein precipitation using acetonitrile, after addition of terazosin as an internal standard. Separation was achieved with a reversed-phase C18 column (250 mm x 4.6 mm) employing UV detection at 215 nm. The mobile phase consisted of 0.02 M potassium dihydrogenphosphate solution adjusted to pH 6.9 with 2 M potassium hydroxide solution-acetonitrile (80:20 (v/v)) at a flow rate of 1.5 ml/min. The total run time was 21.0 min. The assay was linear from 0.2 to 25 microg/ml with goodness of fit (r2) greater than 0.99 observed with three precision and accuracy batches during validation. The observed mean recoveries were 89.3 and 98.0% for drug and internal standard, respectively. The applicability of this method to pharmacokinetic studies was established after successful application during a 34-subject bioavailability study. The method was found to be precise, accurate and specific during the study.     

The photochemistry of polymers containing anthrylmethyl vinyl ketone

The photolysis of copolymers of anthrylmethyl vinyl ketone (AMVK) with styrene and methyl methacrylate has been studied, both in solution and in the solid phase. Quantum yields of the order of 0.01 were observed in both cases for release of the major product, methyl anthracene (MA). Photolysis of an aqueous emulsion of a styrene-AMVK copolymer showed similar yields of MA. The results indicate the possibility of using the Norrish type I process as a means of releasing drugs or other biologically active compounds from polymeric matrices. © 1995 John Wiley & Sons, Inc.     

In Silico Studies and Design of Scrupulous Novel Sensor for Nitro Aromatics Compounds and Metal Ions Detection

Journal of Fluorescence - A Novel calix[4]pyrrole system bearing carboxylic acid functionality [ABuCP] has been synthesized and its interaction towards various nitroaromatics compounds [NACs] were...     

The RNA2-PNA2 hybrid i-motif-a novel RNA-based building block

We report the formation of a hybrid RNA2-PNA2 i-motif comprised of two RNA and two PNA strands based on the sequence specific self assembly of RNA, with potential as a building block for structural RNA nanotechnology.