[en] The 13th international symposium on advanced materials (ISAM) was held from september 23-27, 2013, at islamabad, Pakistan. The main theme of this conference was to discuss the ever increasing changes and intricacies that characterize modern industry necessitate a growing demand for technical information on advanced materials. In five day of the symposium, nearly Two hundred and twenty seven contributory and invited papers, comprising of Nineteen technical sessions and two poster sessions were presented. Renowned scientists and researchers from foreign and local institutes have shared their counter parts on the topics of common interest. This symposium provided an ideal opportunity for exchange of information amongst scientists, engineers and researchers from all over pakistan and other countries of the world. (A.B.)

[en] Ultrasonic testing has a strong application in defect detection. An efficient tool for characterizing and life assessment of material structure and components by nondestructive ultrasonic velocity was developed about thirty years ago. Cold rolling results in increase in strength and hardness. The work discussed here is to study quantitative ultrasonic longitudinal velocity for characterizing a change in microstructure due to cold rolling in austenitic stainless steel samples. Samples were cold rolled up to 80 percent in 10 percent step. It was found that the use of velocity measurements is a useful quantitative and non-destructive tool for characterizing amount of cold rolled austenitic stainless steel. (author)

[en] To determine the frequency of diabetes mellitus in non ST segment elevation myocardial infarction. Study Design: Cross-sectional. Place and Duration of Study: The study was carried out at the Armed Forces Institute of Cardiology (AFIC) Rawalpindi, from Apr 2010 to Oct 2010. Material and Methods: In this study three hundred fifty two patients with non ST elevation myocardial infarction (NSTEMI) who fulfilled the inclusion criteria were studied while they were admitted to the hospital. They were divided into diabetic and non diabetic groups. Frequency of age, gender, rising levels of cardiac biochemical markers, plasma glucose and HbA1c were seen in both diabetic and non diabetic patients. Results were obtained by using chi-square method and independent t-test. Results: Out of 352 patients of NSTEMI 193 were diabetics. The study population was categorized in three groups according to age as; 30-45, 46-60, and 61-75 years respectively. It was found that 46-60 years group was most frequently affected with frequency of 46.1%, p<0.001 with male predominance as 67.9% and females as 32.1%. Cardiac biochemical markers were raised with mean for CK 528.51 U/L SD +- 275.82 and CK MB 79.39 U/L SD +- 32.5, p<0.001 respectively. Raised fasting plasma glucose was found in 189 patients mean 8.74 mmol/L SD +- 1.52, p<0.001 and elevated HbA1c seen in 187 patients mean 7.94% SD +- 0.83, p<0.001. Conclusion: Despite modern therapies for unstable angina (UA)/NSTEMI diabetes is an independent cardiovascular risk factor, therefore we need aggressive strategies to manage the high risk group of patients. (author)

[en] Austenitic stainless steel with submicron gain size has been attracted due to fine structural control of mechanical properties. In order to achieve a submicron grain size, meta-stable austenitic steel AISI 304 is severely cold deformed and then annealed to different heat treatment cycles. The heat treated samples were then tested for metallurgical phase change, texture components and hardness. It was observed that at 750 deg. C, all the martensite transformed completely into austenite. Further, at the same temperature, it was observed that the texture component (221)<232> was the dominant texture component. (author)

[en] Thermal barrier coatings (TBCs) are multilayered coatings having the complex structure. In thermal spray coatings characteristic features of deposited molten particle and its microstructure is very important in defining coating properties. In this work stainless steel (AISI 316) was used as substrate material on which bond coat of Ni-20Cr and top coat of CaZrO/sub 3/ were deposited by air plasma spraying method. Effect of isothermal treatment on the internal microstructure structure of lamella (splat) and phase changes in CaZrO/sub 3/ coating was studied. The fractured surface of coatings was investigated to observe the splat morphology. It was observed that the nano crystallites present within the splat grew with increase in temperature. Further, the monoclinic phase was formed as function of temperature and time. (author)

[en] The pressure bulkhead of a passenger aircraft ruptured when the aircraft was cruising at a height of 28,000 ft. Because of the sudden rupture, the rear toilets disintegrated and things like toilet rolls, tissue papers, towels, were sucked into the stabilizer compartment, where the entire tail control system was located. The debris damaged the green hydraulic system, ruptured fuel line and jammed the control cables. The damage resulted in the aircraft going into pitch-up mode (take-off position) and almost approached stalling position. The failed part was located near the toilets. Water from the toilets reached in this region due to leakage and penetrated inside the sheets and corrosion started in the presence of stagnant water. This was supplemented by the stresses present on the structure during flight. Stress corrosion started from inner sheet and led to initiation of fatigue. The combined effect of stress corrosion cracking and fatigue resulted in the failure of this sheet. No third stage (catastrophic) failure was observed in the fracture. The absence of catastrophic failure mode in the fractured sheet showed that it stood up to last stage. (author)

[en] Titanium aluminides intermetallic compounds have received great attention during the past decade, since they have the potential, in aircraft and automotive engines, to replace the high density Ni-base superalloys However, these intermetallics possess poor oxidation properties at high temperatures. Previous studies showed that protective alumina scale formation on gamma-TiAl can be obtained by small additions (around 2 at.%) of Ag. In the present study, a number of cast Ti-Al-Si alloys were investigated in relation to transient oxide formation in air at 1300 deg. C. After various oxidation times the oxide composition, microstructure and morphology were studied by combining a number of analysis techniques. The TiAl-Si alloys appear to form Al Ti and Si oxides. However, the formation of silicon oxide at the interface of base metal and scale slows down the oxidation rate significantly. (author)

[en] Fluxes are generally used for two purposes to lower the melting point and to decrease the viscosity of the slag. Calcium oxide or lime acts as a major flux in BOF steel making. When lime charged to the converter it reacts with silica to form dicalcium silicates and slag becomes viscous. At this instant flour spar charged to the converter which increases the fluidity of the slag. At Pakistan Steel Mill initially local grade flour spar be used which was not consistent in composition, ultimately it use became abandoned and good quality flourspar be imported from Iran and China. Unfortunately, the reserves of good quality flollrspar not only small in Pakistan but whole over the world. This interrupted-supply often created crises like situation for steel making department. further, the environment unfriendly gases evolved during its reactions. In this context this research was carried out in order to search suitable substitute(s) of flourspar. With in the laboratory limitations experiments were designed. For this purpose tube furnace selected in which different experiments performed to observe the behavior of slag. Experiments demonstrated that Mill scale (FeO) and Alumina are good fluidizers. Iron oxide (FeO), which produced by the control of lance height, substitutes completely the need of flourspar in low carbon steels. The results are discussed in context of different flux practices. (author)

[en] The influence of sliver on the oxidation resistance and relative fracture toughness of aluminum rich gamma titanium aluminide was studied. The titanium aluminide buttons were prepared in argon protected environment. The samples were tested and characterized with the help of Vickers hardness testing machine, optical and scanning electron microscope and energy dispersive spectrometer. The relative fracture toughness was determined by indentation method. It was observed that for a certain alloying addition the oxidation resistance and the relative fracture toughness can be improved. (author)

[en] Thermal barrier coatings (TBCs) were sprayed on stainless steel coupons by an air plasma thermal spray (APS) technique. The porosity of the topcoat was varied by controlling the different spraying parameters. Three types of thermal shock tests were designed to determine the TBCs life. Effect of different spraying parameters on the thermal shock life was observed. The spraying distance was found an important parameter that controls the thermal shock life. It was observed that the thermal shock properties could be related with an empirical parameter called the critical thermal shock parameter (CTSP). Fracture toughness (K/sub ic/) was determined by Vicker's indentation technique and it was observed that for a certain range of the porosity the toughness increased with increase of porosity. The possible increase in thermal shock life for a certain range of CTSP maybe attributed to residual stresses and increase in fracture toughness of the topcoat. (author)