A Compact 1:4 Lossless T-Junction Power Divider Using Open Complementary Split Ring Resonator

This paper presents the size miniaturized and harmonic suppressed lossless 1:4 T-junction unequal power divider using an open complementary split ring resonator (OCSRR). By embedding the OCSRR structure in the microstrip transmission line, slow wave effect is introduced and thereby size reduction is achieved. The dimensions of OCSRR are optimized to reduce the length of high impedance and low impedance quarter-wavelength transmission lines. In our design high impedance line length is reduced to 58.6%, and low impedance line length is reduced to 12% when compared to the conventional quarter wavelength lines. The proposed power divider is having small dimensions of 0.18 λg × 0.33 λg and is 51.94% smaller than the conventional unequal power divider

Transient Analysis of Primary Feed Pump Trip for 700 MWe IPHWR

700 MWe Indian Pressurized Heavy Water Reactor (IPHWR) is a horizontal channel type reactor with two loops of Primary Heat Transport (PHTS) system. Three (two operating and one stand by) main boiler feed water pumps (BFP) supply feed water to Steam Generators (SGs). In the event of one of the running BFP trip, standby comes on line on auto. Transient analysis for this event is performed using in- house computer code ATMIKA.T .The transient has been initiated by tripping one of the pumps. Two cases are postulated: 1: BFP Trip and Standby BFP available on auto 2: BFP Trip and Standby pump not available. This paper provides timelines of following sequence of events which is important for operator’s action to maneuver the event, and the main findings of the study are: Following the tripping of one BFP, feed flow reduces and SGs level start falling. As SGs level fall, feed control valves open up in level control mode and system resistance in feed water circuit reduces. If the standby pump comes on auto, the SGs level recovers with a slight dip in level. The feed flow increases and settles down to normal value. Subsequently all the parameters converge to steady state value. Reactor continues to operate at 100% FP. In the event of main BFP trip without the availability of standby BFP, feed flow rate drops. SGs pressure rise slightly due to reduction in sub cooled feed flow and SGs level start to decrease. Reactor setback starts as SG level goes below set back limit. SG level continues to fall and reactor trips on SG Level very very low trip setting

Formulation and Evaluation of Matrix tablets of Ambroxol hydrochloride using Natural hydrophilic polymer

Se prepararon comprimidos matriciales de liberación prolongada de clorhidrato de ambroxol con diversas proporciones de fármaco: polímero tales como F-1(1:1), F-2(1:1,5) y F-3 (1:2). Se utilizó goma xántica para la formación de la matriz y celulosa microcristalina como diluyente. Se prepararon y evaluaron gránulos para determinar la densidad aparente sin compactar, la densidad compactada, el índice de compresibilidad, el índice de Hausner y el ángulo de reposo. Todos los gránulos se lubricaron y comprimieron con punzones planos de 9 mm. Los comprimidos se evaluaron para determinar la uniformidad de peso, el contenido de principios activos, la friabilidad, la dureza y la disolución in vitro. Todas las formulaciones se ajustaron a los estándares farmacopeicos. F-3 mostró una liberación prolongada de fármaco durante 12 horas con una liberación del 97,3% y el perfi l de liberación fue similar al de la muestra de clorhidrato de ambroxol comercial (A-MS). Además, se realizaron estudios de estabilidad según la guía ICH. La liberación de fármaco sigue cinéticas de orden cero (0,9661) y se determinó que el mecanismo era difusión combinada con erosión.Sustained release matrix tablets of ambroxol hydrochloride of different drug: polymer ratios, such as F-1(1:1), F- 2(1:1.5) and F-3 (1:2). Xanthan gum was used as matrix former and microcrystalline cellulose was used as diluent. Granules were prepared and evaluated for loose bulk density, tapped density, compressibility index, hausners ratio and angle of repose. All the granules were lubricated and compressed using 9mm fl at-faced punches. Compressed tablets were evaluated for uniformity of weight, content of active ingredient, friability, hardness and In-vitro dissolution. All the formulations showed compliance with Pharmacopoeial standards. F-3 showed the sustained release of drug for 12 hours with 97.3% release and the release profi le was close to the marketed sample of ambroxol hydrochloride (A-MS) and Stability studies were performed as per ICH guide. The drug release follows zero order kinetics (0.9661) and the mechanism was found to be diffusion coupled with erosion

13C-Methyl isocyanide as an NMR probe for cytochrome P450 active site

The cytochromes P450 (CYPs) play a central role in many biologically important oxidation reactions, including the metabolism of drugs and other xenobiotic compounds. Because they are often assayed as both drug targets and anti-targets, any tools that provide: (a) confirmation of active site binding and (b) structural data, would be of great utility, especially if data could be obtained in reasonably high throughput. To this end, we have developed an analog of the promiscuous heme ligand, cyanide,with a 13CH3-reporter attached. This 13C-methyl isocyanide ligand binds to bacterial (P450cam) and membrane-bound mammalian (CYP2B4) CYPs. It can be used in a rapid 1D experiment to identify binders, and provides a qualitative measure of structural changes in the active site

Chemical Transformations Using Tungsten and Molybdenum Hydrogen Bronzes

Chemistr