Comparison between experimental and 2-D numerical studies of multiple scattering in Inconel600 by means of array probes

Ultrasonic non-destructive testing of polycrystalline structures can be disturbed by scattering at grain boundaries. Understanding and modeling this so-called "structural noise" is crucial for characterization as well as detection purposes. Structural noise can be considered as a fingerprint of the material under investigation, since it contains information about its microstructure. The interpretation of experimental data necessitates an accurate comprehension of complex phenomena that occur in multiple scattering media and thus robust scattering models. In particular, numerical models can offer the opportunity to realize parametrical studies on controlled microstructures. However, the ability of the model to simulate wave propagation in complex media must be validated. In that perspective, the main objective of the present work is to evaluate the ability of the finite-element code ATHENA 2D to reproduce typical features of multiple wave scattering in the context of ultrasonic non-destructive evaluation, with an array of sources and receivers. Experiments were carried out with a 64-element array, around 2 MHz. The sample was a mock-up of Inconel600 exhibiting a coarse grain structure with a known grain size distribution. The numerical model of this microstructure is based on Voronoi diagrams. Two physical parameters were used to compare numerical and experimental data: the coherent backscattering peak, and the singular value distribution of the array response matrix. Though the simulations are 2-D, a good agreement was found between simulated and experimental data.

Antioxidant status in coronary heart disease (CHD) patients with type 2 diabetes mellitus

BACKGROUND

The present study was carried out to see the levels of vitamin C, vitamin E and total antioxidant (AO) in Coronary Heart Disease (CHD) patients with and without Type-2 Diabetes Mellitus (T2DM). In various previous studies it has been reported that, diabetes, hypertension and smoking are risk factors for CHD and all risk factors were common in these patients.

METHODS

Serum was tested from 80 CHD patients and 21 healthy controls, matched for age, height, and weight.

RESULTS

No significant difference was seen between the age, height and weight of the subjects and controls. CHD patients were mostly male, smokers, over 40 year of age and belonging upper class families. The mean plasma glucose was significantly higher (p < 0.05) in CHD patients having T2DM as compare to CHD patient with out T2DM. Risk factors for CHD, like diabetes, hypertension and smoking were common in these patients. No significant difference was seen in vitamin C level of patients of CHD. Vitamin E level was significantly (p < 0.05) low among the CHD patients as compared to controls and a significant (p < 0.05) decrease in mean vitamin E level was observed among smoker CHD patients as compared to non-smoker CHD patients. But no significant difference in vitamin C and vitamin E levels of CHD patients with diabetes and hypertension were observed when compared with CHD patients having no such complaints. The CHD patients' total antioxidant level was significantly (p < 0.05) decreased as compared to controls.

CONCLUSION

The total AO (Vit. C and E) were not significantly higher in CHD patients with hypertension and diabetes as compared to those patients of CHD having no hypertension and diabetes.

Study of lipoprotein patterns as an atherogenic factor in T2DM patients and their FDRs

BACKGROUND

The present study was carried out to determine the lipoprotein patterns as an atherogenic factor in T2DM (Type 2 Diabetes Mellitus) patients and their FDRS (First Degree Relatives). In various previous studies it has been reported that hyperinsulinemia and hyperlipidemia frequently coexist in T2DM patients which indicate that the diabetic state it self is associated with atherogenic lipid disorders.

METHOD

The present study included 26 Type 2DM (T2DM) patients and 21 apparently healthy First Degree Relative (FDRs) of T2DM patients. Twenty three age matched control not related to diabetics were also included in the study.

RESULTS

The BMI in male patients and FDRs were significantly higher as compared to controls but no significant difference was seen among the BMI of female FDRs. Fasting plasma glucose (FPG) levels of T2DM patients were significantly higher but no significant difference was observed among the FDRs and controls. FPG did not show any significant correlation with the BMI in diabetic patients, FDRs and controls. The lipid profile of patients showed no significant difference, except the mean LDL-Chol of female patients was significantly higher as compared to female controls. HDL-Chol of males FDRs was significantly lower as compared to male controls. LDL-Chol of female FDRs was significantly lower than the female controls. No significant difference was observed in the total cholesterol and the triglycerides level of the patients of T2DM and FDRs but those cases in which pre-beta band appear upon lipoprotein electrophoresis had significantly higher triglyceride levels as compared to those patients in which pre-beta band did not appear.

CONCLUSION

Lipoproteins of the T2DM patients and FDRs group were found to be highly disturbed as compared to the control group and they show a trend of developing atherogenic states in future.