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Search Results: 1 - 10 of 401390 matches for " M. Gude "
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RP-HPLC estimation of ramipril and telmisartan in tablets
Kurade V,Pai M,Gude R
Indian Journal of Pharmaceutical Sciences , 2009,
Abstract: A rapid high performance liquid chromatographic method has been developed and validated for the estimation of ramipril and telmisartan simultaneously in combined dosage form. A Genesis C18 column having dimensions of 4.6x250 mm and particle size of 5 μm in isocratic mode, with mobile phase containing a mixture of 0.01 M potassium dihydrogen phosphate buffer (adjusted to pH 3.4 using orthophosphoric acid): methanol:acetonitrile (15:15:70 v/v/v) was used. The mobile phase was pumped at a flow rate of 1.0 ml/min and the eluents were monitored at 210 nm. The selected chromatographic conditions were found to effectively separate ramipril (R t : 3.68 min) and telmisartan (R t : 4.98 min) having a resolution of 3.84. The method was validated in terms of linearity, accuracy, precision, specificity, limit of detection and limit of quantitation. Linearity for ramipril and telmisartan were found in the range of 3.5-6.5 μg/ml and 28.0-52.0 μg/ml, respectively. The percentage recoveries for ramipril and telmisartan ranged from 99.09-101.64% and 99.45-100.99%, respectively. The limit of detection and the limit of quantitation for ramipril was found to be 0.5 μg/ml and 1.5 μg/ml respectively and for telmisartan was found to be 1.5 μg/ml and 3.0 μg/ml, respectively. The method was found to be robust and can be successfully used to determine the drug content of marketed formulations.
The Curing Process of Epoxy/Amino-Functionalized MWCNTs: Calorimetry, Molecular Modelling, and Electron Microscopy
S. G. Prolongo,M. R. Gude,A. Ure?a
Journal of Nanotechnology , 2010, DOI: 10.1155/2010/420432
Abstract: Curing kinetic of an epoxy resin reinforced with amino-functionalized MWCNTs has been studied by DSC and the obtained results were explained through morphological studies carried out by SEM, TEM, FEG-SEM, and molecular simulation tools. The presence of MWCNTs in the curing reaction induces a retardation effect of curing reaction and a decrease of the reaction heat. Both are associated with the adsorption of curing agent molecules inside carbon nanotubes, which was proved through the application of electron microscopic techniques and molecular simulation tools. It has been also demonstrated that there is a chemical reaction between amine groups anchored to the nanotubes and oxirane rings of epoxy monomer, which improves the nanoreinforcement/matrix interfacial adhesion, appearing a chemical interphase. The glass transition temperature ( ) of epoxy matrix increases by the addition of MWCNTs due to the restriction of its mobility. 1. Introduction Epoxy resins are commonly used as polymeric matrices in high-performance composites. Carbon nanotubes (CNTs) are promising fillers to improve their mechanical, thermal and electrical behaviour [1, 2]. Numerous studies have been published about the fabrication and characterisation of CNT/epoxy nanocomposites [3–5]. The most of researches show moderate results regard to the theoretically expected ones. The properties of nanocomposites are improved regarding those showed by neat epoxy resins but they are not usually higher than the ones of conventional microscale composites. Poor dispersibility and high chemical inertness of as-synthesised carbon nanostructures can be the main processing limitations. In order to increase the compatibility between CNTs and epoxy matrix, an initiative consists on the introduction of polar groups on the surfaces of nanotubes [6, 7]. The nanoreinforcements are covalent functionalized through reactive linker molecules, which can later react with functional groups of the matrix, providing interfaces of high covalent integrity. In particular, amino-functionalized CNTs are being widely investigated [8–10] as fillers of epoxy resins. The thermal and mechanical characterisation of epoxy nanocomposites reinforced with amino-functionalized CNTs has been already tackled by several authors, showing some contrary results. In concrete, some works [9, 10] show that the glass transition temperature ( ) of epoxy matrix increases by the addition of amino-functionalized carbon nanotubes. This fact has been associated to the lower mobility of the epoxy moiety when it reacts with amino groups immobilized
Process Chain Modelling and Analysis for the High-Volume Production of Thermoplastic Composites with Embedded Piezoceramic Modules
W. Hufenbach,M. Gude,N. Modler,Th. Heber
Smart Materials Research , 2013, DOI: 10.1155/2013/201631
Design, manufacture and technological verification of SiC/C composite stirrer
A. Dolata-Grosz,W. Hufenbach,J. ?leziona,M. Gude
Archives of Materials Science and Engineering , 2009,
Abstract: Purpose: In article were presented assumptions and choose results of investigations connected with material selection and technology production of prototype’s ceramic stirrer with destination to work in environment of liquid metal. In the research work the result of the design, manufacture and technological verification of SiC/C composite stirrer have been presented.Design/methodology/approach: The design of the stirrer (2D and 3D models) and strength tests on the blade and fragment of the composite axle was prepared in the programme Solid Works and the FEM, using COSMOS software. Polymer infiltration and pyrolysis (PIP) technique was used for fabrication SiC/C stirrer. Examination of wettability and suitability of the SiC/C composite for application in a liquid metal with sessile drop wettability was conducted. The surface geometry, conducted using a non-contact optical profilometer, FRT Micro’Prof.Findings: Further laboratory tests of the SiC/C composite stirrer, designed and developed in the Institute of Lightweight Engineering and Polymer Technology at TU Dresden have confirmed rightness of the design, assumptions regarding the thermal, mechanical and chemical resistance of the stirrer.Practical implications: The technological tests have proven a considerable reduction of the turbulence flow, which with an unchanged system of controlling the stirrer ensured stability of the liquid metal whirl and repeatability of the process.Originality/value: The application of this new material will enable not only the expansion of laboratory research, but it may also facilitate the implementation of liquid/phase technologies of obtaining MMC composites for the industry and thus, contribute to increasing the durability of stirrers in comparison with the solutions applied so far.
Development of novel piezoceramic actuator modules for the embedding in intelligent lightweight structures
W. Hufenbach,M. Gude,N. Modler,C. Kirvel
Journal of Achievements in Materials and Manufacturing Engineering , 2007,
Abstract: Purpose: Piezoceramic actuators in lightweight structures enable a purposeful manipulation of the dynamic and vibroacoustic structural behaviour. Above it, further studies focus on the application of thin and flexible piezoceramic modules as power sources in morphing structures aiming at a shape adaptation.Design/methodology/approach: A specific example of novel morphing structures is introduced, which rely on multistable deformation phenomena of fibre-reinforced composites with an unsymmetric lay-up. For the large-scale capable utilisation of such active struc tural parts made of fibre-reinforced thermoplastic composites, novel piezoceramic modules, which are specifically tailored to the structural material, and required manufacturing methods are developed.Findings: The piezoceramic modules with the highly regarded compatibility to ther moplastic composites permit their substantially coherent and homogeneous integration in the fibre composite structure without intricate adhesive assembly effort. Furthermore, thermally induced residual compressive stresses during the manufacturing process serve for pur posefully prestressing the piezoceramic components to reduce the module’s sensitivity to tensile loading.Research limitations/implications: For the manufacture of those novel piezoceramic modules, a continuously operating fabrication method has been developed. By the process-related integration of a hot press, residual compression stresses are thermally induced into the modules that considerably contribute to the decrease of the piezoceramic module’s sensitivity to tension.Originality/value: The successful development of the novel TPM offers a significant advancement in the efficieny within the large scale production of novel intelligent lightweight structures.
Development of textile-reinforced carbon fibre aluminium composites manufactured with gas pressure infiltration methods
W. Hufenbach,M. Gude,A. Czulak,J. ?leziona
Journal of Achievements in Materials and Manufacturing Engineering , 2009,
Abstract: Purpose: The aim of his paper is to show potential of textile-reinforced carbon fibre aluminium composite with advantage of the lightweight construction of structural components subjected to thermo-mechanical stress.Design/methodology/approach: The manufacture of specimens of the carbon fibre-reinforced aluminium was realised with the aid of an advanced differential gas pressure infiltration technique, which was developed at ILK, TU Dresden.Findings: The gas pressure infiltration technology enables to fabricate complex carbon aluminium composites with fibre or textile reinforcement using moulds of graphite, but in future development the optimization of infiltration process is required. The load-adapted combination of 3D reinforced semi-finished fibre products (textile preforms) made from carbon fibres (CF) with aluminium light metal alloys (Al) offers a considerable lightweight construction potential, which up to now has not been exploited.Research limitations/implications: Gas pressure infiltration technology enables to fabricate complex carbon aluminium composites with fibre or textile reinforcement using precision moulds of graphite, but in future development the optimization of infiltration process is required.Practical implications: Load-adapted CF/Al-MMC, due to the relatively high stiffness and strength of the metal matrix, allow the introduction of extremely high forces, thereby enabling a much better exploitation of the existing lightweight construction potential of this material in comparison to other composite materials.Originality/value: Constantly rising demands on extremely stressed lightweight structures, particularly in traffic engineering as well as in machine building and plant engineering, increasingly require the use of endless fibre-reinforced composite materials which, due to their selectively adaptable characteristics profiles, are clearly superior to conventional monolithic materials.
Novel tests and inspection methods for textile reinforced composite tubes
W. Hufenbach,L. Kroll,M. Gude,A. Czulak
Journal of Achievements in Materials and Manufacturing Engineering , 2005,
Abstract: Purpose: This paper describes innovative lightweight applications of fiber and textile reinforced polymers in aircraft, automotive and chemical industry.Design/methodology/approach: This paper deals with modern test methods of braided composite tube specimens as basic elements of modern composites. The tubes subjected to strength tests under superposed compressive, tensile and internal pressure loadings, and tested by the acoustic emission method for damage detection.Findings: For the quality assessment and here, especially for the verification of fibre orientations after manufacture, the X-ray method is an advantageous inspection method. For the identification of fracture modes, after uni- and biaxial mechanical test under tensile, compressive and torque loads as well under inner pressure loading the computer tomography CT is used. The acoustic emission to assess for damage detection in braided composite pipes, and mechanical loading. Moreover, from the applied techniques the information concerned quality of a manufactured specimen, damage propagation and determination the types of damages can be obtained.Research limitations/implications: Those three methods assure very good and promising results having one limitation in case of volume of a tested sample, e.g in the CT device, an allowable diameter of an investigated tubular specimen amounts to 150mm.Practical implications: Use of the methods resulted in improved efficiency of test process and analysis of GFRP tubular specimens.Originality/value: The paper describes the new implicated test and inspection methods for textile reinforced composite tubes.
Battling chemotherapy-induced nausea and vomiting in cancer palliative care
Gude Dilip
Indian Journal of Palliative Care , 2011,
Heart and ECMO: Are we ready?
Gude Dilip
Annals of Cardiac Anaesthesia , 2011,
Remifentanil: Much ado about something
Gude Dilip
Annals of Cardiac Anaesthesia , 2011,
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