Study of Mach reflection in inviscid flows

In this paper, we study the Mach reflection phenomenon in inviscid flows using a higher order discontinuous Galerkin method and overset grids. We use the shock capturing procedure proposed in Siva Prasad Kochi et al. using overset grids to capture the discontinuities occurring in the supersonic flow over a wedge accurately. In this procedure, we obtain a coarse grid solution first and using the troubled cell data, we construct an overset grid which is approximately aligned to all the discontinuities. We rerun the solver with the coarse grid solution as the initial condition while using the troubled cell indicator and the limiter only on the overset grid. This allows us to capture the discontinuities accurately. Using this procedure, we have obtained the solution for Mach $3.0$ and $4.0$ flow over a wedge for various wedge angles and determined the detachment criterion and the Von Neumann condition accurately. We have also determined the Mach stem height for various wedge angles for these Mach numbers. We have also demonstrated the hysteresis that occurs in the transition from regular reflection to Mach reflection.Comment: 11 pages, 8 Figures, 2 Table

Characterization of Printed Podal Vivaldi Antenna (8–18 GHz) on RT Duroid with Single and Double Cavity

In today’s modern communication systems, miniaturized and lightweight subsystems covering broad bandwidth are in much demand as they lead to realization of very compact and lightweight systems. A printed podal Vivaldi antenna with single as well as double cavities fed with strip line transmission line and operating from X band to KU band (8–18 GHz) is proposed. The comparison of antenna performance for single cavity and double cavity is also reported. Using double cavity, the miniaturization of antenna is possible as compared to single cavity Vivaldi antenna. The antenna is first designed using conventional theoretical approaches. Later, it is simulated using a 3D EM simulation software, CST Microwave StudioTM. The optimal value for taper length is 6.86455 cm and cavity diameter is 1.582 cm. Finally, the design is physically fabricated using PCB technology for carrying out practical measurement. The antenna’s input impedance characteristic is measured in the form of S-parameter and VSWR using Vector network analyzer. VSWR less than 3:1 is achieved over the band from 8 to 18 GHz. The radiation pattern measurements are carried out in anechoic chamber. The proposed Vivaldi antenna is used for digital data transmission via satellites and for voice/audio transmissions

Incidentally detected solid pseudopapillary neoplasm of pancreas in a child with an ovarian cyst: a case report

Solid pseudopapillary neoplasms (SPN) are the most common as well as very rare pediatric tumors of the pancreas. Most of the literature is derived from adult SPNs. As per world health organization, these tumors considered as low grade malignant with excellent survival outcomes after complete surgical resection. We report a case of incidentally detected SPN in a 16-year-old female child with an ovarian cyst. She underwent pylorus preserving pancreaticoduodenectomy and ovarian cystectomy. Histopathology revealed well differentiated SPN of the pancreas head and ovarian cystadenoma. She is symptom-free at the 6th month follow up

CRITICAL REVIEW ON DESIGN OF ROLLING PROCESS

Rolling is one of the important forming processes used in steel industry. During rolling process because of overdraft and poor die design, cracks and breakage of rolls takes place, leading to shutdown of rolling mill. There is a need for proper deign of rolling dies based on work piece material. In the present paper design methodologies followed by various researchers are presented. Review on works related to Finite Element Analysis (FEA) methods and material selection is carried out and presented.

VOLTAMMETRIC DETERMINATION OF DESLORATADINE IN PHARMACEUTICAL AND HUMAN URINE SAMPLES USING GLASSY CARBON ELECTRODE

Objective: The electrochemical behaviour of Desloratadine (DLTD) in pharmaceutical and human urine samples at glassy carbon electrode was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Methods: A well defined reduction peak was observed at potential -1.55V in phosphate buffer solution (PBS) in basic medium. The reduction process was observed to be irreversible over the pH range from pH 2.0 to pH 10.0. The influence of different parameters such as the effect of pH, scan rate and concentration of the drug was studied. The probable reaction mechanism involved in the reduction of DLTD was also proposed. A SWV method with good recovery and accuracy was obtained for the determination of DLTD in pharmaceutical formulations and urine samples. Results: The peak currents were found to be linearly dependent on the concentration range of 2.55x10-5to 1.5x10-3M of DLTD. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 2.75x 10-9M, 3.20x 10-7 M respectively. Conclusion: The proposed method was successfully applied for determination of DLTD in pharmaceutical and human urine samples