Internal stress wave measurements in solids subjected to lithotripter pulses

Semiconductor strain gauges were used to measure the internal strain along the axes of spherical and disk plaster specimens when subjected to lithotripter shock pulses. The pulses were produced by one of two lithotripters. The first source generates spherically diverging shock waves of peak pressure approximately 1 MPa at the surface of the specimen. For this source, the incident and first reflected pressure (P) waves in both sphere and disk specimens were identified. In addition, waves reflected by the disk circumference were found to contribute significantly to the strain fields along the disk axis. Experimental results compared favorably to a ray theory analysis of a spherically diverging shock wave striking either concretion. For the sphere, pressure contours for the incident P wave and caustic lines were determined theoretically for an incident spherical shock wave. These caustic lines indicate the location of the highest stresses within the sphere and therefore the areas where damage may occur. Results were also presented for a second source that uses an ellipsoidal reflector to generate a 30-MPa focused shock wave, more closely approximating the wave fields of a clinical extracorporeal lithotripter

Flexural analysis of deep beam subjected to parabolic load using refined shear deformation theory

A trigonometric shear deformation theory for flexure of thick or deep beams, taking into account transverse shear deformation effects, is developed. The number of variables in the present theory is same as that in the first order shear deformation theory. The sinusoidal function is used in displacement field in terms of thickness coordinate to represent the shear deformation effects. The noteworthy feature of this theory is that the transverse shear stresses can be obtained directly from the use of constitutive relations with excellent accuracy, satisfying the shear stress free conditions on the top and bottom surfaces of the beam. Hence, the theory obviates the need of shear correction factor. Governing differential equations and boundary conditions are obtained by using the principle of virtual work. The thick isotropic beams are considered for the numerical studies to demonstrate the efficiency of the theory. It has been shown that the theory is capable of predicting the local effect of stress concentration due to fixity of support. The fixed isotropic beams subjected to parabolic loads are examined using the present theory. Results obtained are discussed critically with those of other theories

Utilisation pattern of AMA in surgery department in a tertiary care hospital

 In the recent past when people were dying of communicable diseases, the discovery and innovations of AMAs , did a miracle as saved millions of life worldwide, by special toxic and killing effect on infecting microorganisms and not damaging host, thus satisfying own name as  MIRACLE MEDICINE or MAGIC BULLETS. Paul Ehlrich of Austria discovered first time chemotherapeutic agent in 1906. Next Domagk of Germany, A. Fleming of England, Walks man of USA discovered sulfonamides, penicillin, Streptomycin and all received NOBEL PRIZE, for their immortal lifesaving work which changed world. Data are collected from admitted patient’s case sheets from surgery wards .Data’s are collected by a self-prepared preformed proforma, which is prepared as per study design and includes Age, Sex, Disease, Unit, Ward, AMA or AMAs prescribed, Average no of AMAs, Dose, Frequency, Route of administration, along with Govt. supply or private purchase and supply chain