Distribution of resistive body-force in curved free-surface flow

The customary procedure for including resistive effects in turbulent hydraulic and stratified atmospheric flows is to integrate the empirically-known boundary shears over the entire wetted boundary of a thin fluid slab. A resistive body-force is then assumed to exist everywhere in each slab to replace the boundary shearing force. For the classical Saint-Venant model, this body-force can be shown to have a constant distribution in the vertical direction, and therefore can be evaluated for use in the momentum differential equation. In the newer Dressler theory, however, for unsteady flow over curved beds, it is proved here that a constant body-force distribution is not possible. We determine its variable distribution and its magnitude for use in the curved-flow equations. This vasriable distribution acts to produce an equal resultant in every thin layer of fluid parallel to the bed in an angular wedge over the curved channel bed. The new curved-flow equations are therefore extended to include resistive effects.     

Validation of capillary electrophoresis method for determination of N-methylpyrrolidine in cefepime for injection

The present study relates to a new capillary electrophoresis method for the determination of N-methylpyrrolidine, an impurity considered to be toxic and also potential degradation impurity in cefepime hydrochloride drug substance. The newly developed capillary electrophoresis method for determining the content of N-methylpyrrolidine in cefepime for injection has been validated as per International Conference on Harmonization (ICH) guidelines to prove the selectivity, sensitivity, suitability, robustness, and ruggedness of the method. This simple, efficient, and rapid methodology may be used by pharmaceutical industry for routine analysis as well as during stability studies. The newly developed capillary electrophoresis method to determine the content of N-methylpyrrolidine in cefepime for injection requires 10 min for data acquisition, and uses an indirect UV photometry method to detect the analyte signal at 240 nm against the reference signal at 210 nm. The electrophoretic system is optimized to get stable base line, higher signal to noise ratio and peaks with narrow peak width. The method employs bare fused silica capillary with extended light path, effective length of capillary is 56 cm and inner diameter of capillary is 50 μm, 5 mmole of imidazole buffer adjusted to pH 5.1 with 3 molar acetic acid solution is used as background electrolyte. The sample is introduced in hydrodynamic mode employing pressure of 50 mbar for 5 s, and the desired separation is achieved with constant applied voltage of 25 kV at ambient temperature (~25°C).     

Novel Procedure for the Synthesis of 1‐Hydroxy‐1,1‐bisphosphonic Acids using Phenols as Medium

A facile synthetic route for the synthesis of bisphosphonates in phenols is described. Preparations of some of bisphosphonates, which are presently in clinical use such as risedronic acid and alendronate sodium, are synthesized following this new, simple method. This procedure can be useful for the synthesis of this class of bone‐resorptive inhibitors in bulk quantities.     

Novel compounds for the synthesis of cefdinir

Preparation of two new compounds 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazolyl‐(Z)‐2‐(2‐amino‐4‐thiazolyl)‐2‐trityloxyiminoacetate ( 14 ) and 2‐mercapto‐5‐methyl‐1, 3,4‐thiadiazolyl‐ (Z)‐2‐(2‐amino‐4‐thiazolyl)‐2‐acetyloxyiminoacetate ( 12 ) and their use in the preparation of 7β‐[(Z)‐2‐(2‐amino‐4‐thiazolyl)‐2‐hydroxyiminoacetamido]‐3‐vinylcephem‐4‐carboxylic acid, also known by the generic name Cefdinir ( 1 ) has been accomplished in a single step by coupling with 7‐amino‐3‐vinylcephem‐4‐carboxylic acid ( 7 ) with purity of greater than 99% by HPLC.     

A unique control strategy to improve the life cycle of the battery and to reduce the thermal runaway for electric vehicle applications

This paper presents a unique thermal control strategy to improve the ageing of the battery and to maintain the internal temperature of the battery within the optimum limit of 20 °C–40 °C for electric vehicle (EV) applications. The hybrid EV system encompasses photovoltaic (PV) module, high power density device supercapacitor (SC) and high energy density Li-ion battery (LIB) as an energy storage element. The vehicle dynamics encounter frequent voltage fluctuations in the direct current (DC) bus, which ultimately reduces the lifecycle of the battery and also the heat is generated inside the battery when it is connected in parallel to the DC bus. The frequent charging/discharging of LIB is controlled by the unique thermal control strategy of the hybrid EV system. The DC bus voltage is controlled by the SC bi-directional converter (BDC) where, the battery BDC delivers the essential constant current from the main source (PV) to the DC bus. This unique thermal control strategy supports the distribution of power from the PV/LIB/SC hybrid source system to the EV and also improves the battery life cycle. Due to constant charging/discharging of battery the thermal runaway (TR) problem such as leak, smoke, gas venting, rapid disassembly, flames etc., can be eliminated. Decoupling of load power and battery power comprises the growth in the battery lifecycle and to maintain the optimum internal temperature of the LIB by conditional flow of current through hybrid thermal management system (HTMS). To certify the thermal control strategy and to estimate the performance of HTMS, a simulation of a hybrid source system with vehicle dynamics is performed in MATLAB/Simulink. Numerical analysis of the LIB during constant charging/discharging is performed using ANSYS fluent software to validate the temperature effect of HTMS.

     

Nonlinear vibration of generally laminated anisotropic thick plates

Summary Nonlinear equations of motion of generally laminated anisotropic plates are derived by use of Hamilton's principle. The effects of transverse shear and rotatory inertia are included in the analysis. The equations of motion so obtained readily reduce to those obtained in a recent nonlinear theory of anisotropic plates including transverse shear and rotatory inertia and to the dynamic von Kármán equations of plates. Based on the Galarkin procedure and principle of harmonic balance approximate solutions to the governing equations of generally laminated rectangular plates are formulated for various boundary conditions. Including the effects of transverse shear and rotatory inertia numerical results for the ratio of nonlinear frequency to linear frequency of symmetric angle-ply and cross-ply laminates, unsymmetric angle-ply and cross-ply laminates and an arbitrarily laminated plate are presented graphically for various values of elastic properties, fiber orientation angle, number of layers, thickness-to-span ratio and aspect ratio. Present results are also compared with the existing data.

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Nichtlineare Schwingungen von anisotropen, dicken Verbundplatten

übersicht Die nichtlinearen Bewegungsgleichungen anisotroper, dicker Verbundplatten werden mit Hilfe des Prinzips von Hamilton hergeleitet. Dabei werden die Einflüsse der Schubspannungen und der Drehträgheit berücksichtigt. Mit dem Verfahren von Galerkin und der Methode der harmonischen Balance werden Näherungslösungen für Rechteckplatten bei verschiedenen Randbedingungen gewonnen. Numerische Ergebnisse für verschiedene Materialparameter sind graphisch dargestellt und werden mit bereits bekannten Ergebnissen verglichen.

     

Novel azaandrostane derivatives for the synthesis of 17β‐(N‐tert‐butyl carbamoyl)‐4‐aza‐5α‐androst‐1‐ene‐3‐one

A new industrially viable process for the preparation of 1β‐(N‐tert‐butyl carbamoyl)‐4‐aza‐5α‐androst‐1‐ene‐3‐one, also known by the generic name finasteride ( 6 ) from the new azaandrostane derivatives such as 1β‐(N‐tert‐butyl carbamoyl)‐4‐benzoyl‐4‐aza‐5α‐androstane‐3‐one ( 4 ), 1β‐(N‐tert‐butyl carbamoyl)‐4‐benzoyl‐4‐aza‐5α‐androst‐1‐ene‐3‐one ( 5 ) is reported. In this process, benzoyl group is demonstrated as a novel protecting group for lactamic NH group. The structures of newly prepared compounds were established on the basis of spectral data (IR, ¹H‐NMR, and MS).