Muhammad Adil Khattak

Application of Sayong Ball Clay Membrane Filtration for Ni (II) Removal from Industrial Wastewater

Abstract Wastewater containing heavy metals, such as nickel ions (Ni2+), discharged from industry to water streams poses a serious threat because even at low concentrations, it does not naturally degrade and is toxic to human and aquatic life. This article reviews a novel technique for wastewater treatment using a Sayong ball clay (SBC) membrane to remove nickel from industrial wastewater. SBC powder was achieved through milling using a planetary ball mill (milling time; 10, 20 and 30 h), further labelled as SBC 10, SBC 20 and SBC 30, with a ball-to-powder of ratio 7:1 and rotation speed of 300 rpm. The physical characteristics of the apparent porosities, bulk density and shrinkage were investigated. XRD was used to study the phase, while FESEM was used to analyse the microstructure of the fired membrane. The FESEM microstructure indicates a decreased particle size (SB30). Filtration was conducted using a dead-end filtration system. The fabricated SBC 10, 20 and 30 membranes showed significant removal of nickel from industrial wastewater—88.87%, 82.96% and 85.13%, respectively. This study revealed that the SBC membrane is a promising membrane to remove nickel from industrial wastewater. The results also indicate the possibility of highlighting the introduced technique as a new technique for the treatment of industrial wastewater. As a new trend for waste management, pollution prevention could be applied in Malaysia as one of the advanced biotechnologies to solve various environmental problems.

Effect of Pitting Corrosion on Strength of AISI 410 Stainless Steel Compressor Blades

In the present paper, effects of pitting corrosion on the strength of members made of AISI 410 Martensitic stainless steel were investigated. Stainless steel compressor blades in power generation industries commonly suffer from pitting corrosion. Pits geometry analysis and strength tests have been conducted. Pits geometry analysis established the maximum pit depth of 0.26 mm along with the maximum diameter of 1 mm. In addition, strength and elongation of the pitted tensile specimen gradually decrease with the increase of the area lost due to pitting corrosion. A damage nucleation phenomenon at the initial load values is also postulated.

High temperature creep behavior of austenitic Fe-Ni-Cr alloy

Creep damage investigation was carried out in Fe-Ni-Cr alloy at 800°C, 900°C, and 983°C using rectangular section form of specimen. In all the tests conducted on this material, some creep curves showed primary stage, secondary stage and tertiary stage. The creep fracture shows ductile transgranular fracture where separation occurred at the dendrites carbide interface suggesting that the detrimental effect of creep was compounded by precipitation of carbides at matrix. The presence of cavities may be due to the difference in thermal expansion characteristics of the austenite and carbide during high temperature test. Coarsening of carbides lead to cavities formation within the dendrite and carbide interface and form cavities linkage due to formation of crack and finally cause creep fracture. Increase in creep temperature it will lead to increase in creep rate. The fracture modes of creep samples were investigated to predict the failure mode.

2D occupancy grid mapping with inverse range sensor model

This paper describes a system for occupancy grid mapping using an autonomous mobile robot equipped with laser range finder. The approach depicted in this article is the occupancy grid mapping with inverse range sensor model. A complex real time system is developed that exchange and process data between the NI robotics starter kit and an external host computer through TCP layer. All programs are developed using labVIEW. Although, the results were not as expected, the resulting maps can give an approximation of the environment of navigation. The inaccuracy of the maps is explained by the reliance on the odometry data for localization, which makes clear the necessity of simultaneous localization and mapping techniques in the field of autonomous navigation.

Effect of variation in grain size on high temperature creep test of Fe-Ni-Cr alloy

Fe-Ni-Cr or known as Incoloy 800H and Haynes HR120 is a solid solution strengthened iron-nickel based superalloy which is extensively used in high temperature and corrosive environment. The effect of grain size in creep strength and creep rate comes through the grain boundary sliding and grain boundaries as barrier mechanism. This paper describes the effect of microstructural variation of Fe-Ni-Cr on the high temperature creep properties. The materials were heat treated at temperature 1050°C and 1200°C followed by water quenching process. The grain size of the samples of Incoloy 800H is 95.47μm for as-received, 122.81μm for solution treated at 1050°C and 380.95μm for solution treated at 1200°C. And the grain size of the samples of Haynes HR120 is 53.45μm for as-received, 61.50μm for solution treated at 1050°C and 158.27μm for solution treated at 1200°C. The creep damage investigation was carried out in the three different grain sizes of Fe-Ni-Cr superalloy at 900°C with stress at 100MPa. Rectangular section forms of specimens are used in the research. In all the tests conducted, the creep curves show primary, secondary and tertiary stages. The creep fracture surface were characterised by using scanning electron microscope. It was found that larger grain size results in lower creep rate for alloy Haynes HR120 but inverse result showed on alloy Incoloy 800H.

Effects of thermal aging on ductile-to-brittle transition temperature behavior of welded A516 steel

Prolonged high temperature exposure of welded C-Mn steels is likely to cause microstructural changes leading to an inrease in the ductile-to-brittle transition temperature (DBTT) of the welded joint. Consequently, such degrading material properties should be quantified in view of establishing accurate component life prediction model. This study examined effects of isothermal aging on DBTT behavior of the heat affected zone (HAZ) in welded Type A516 Gr 70 steels. Microstructures of the as-received weld region revealed the presence of pearlite and ferrite in the base metal while upper and lower bainite are found in the HAZ and weld metal, respectively. Hardness measures for the weld metal region, HAZ and base steel are 172, 209 and 150, respectively. Aging at 420 oC, 500 hours lowers hardness value of the HAZ by 20 %. A series of Charpy impact tests on V-notched specimens are performed for as-received and thermally aged samples at 420 oC for 500, 800 and 1200 hours. Results showed that the absorbed impact energy displays a sigmoidal variation with test temperatures. DBTT ranges from -60 to 5 oC for HAZ while narrow range from -25 to 12 oC for weld metal region. Absorbed impact energy variations in samples aged for durations up to 800 hours display another saturation level over test temperatures between -30 to 10 oC. Fractographic analysis on HAZ fracture surface indicated brittle fracture at -60 oC while ductile failure dominated at 27.7 oC. A mix-mode fracture mechanism is displayed for test conducted at -38 oC.