Advanced Materials and Processes Research Institute
Advanced Materials and Processes Research Institute, BhopalNot a member yet
809 research outputs found
Sort by
Graphite modified cotton fibre reinforced polyester composites\ud under sliding wear conditions
No full textGraphite modified polyester–cotton composites were developed and studied for friction and sliding wear behaviour at different applied loads and\ud
graphite concentrations. Sliding wear tests were conducted using pin-on-disc apparatus. The composite pins were tested against EN-31 steel disc.\ud
The specific wear rate of polyester reduced on reinforcement of cotton and on addition of graphite. The coefficient of friction of polyester resin\ud
increased on cotton reinforcement and reduced significantly on addition of graphite in cotton–polyester composite. The temperature of contact\ud
surface reduced on addition of graphite in cotton–polyester composite. The reduction in wear rate of graphite modified polyester–cotton composite\ud
has been discussed with the help of scanning electron microscope (SEM) observations of worn surfaces, coefficient of friction and the temperature\ud
of contact surface
Modeling of sorption kinetics of divalent \ud metal ions onto mineral absorbent using\ud integral method
No full textDevelopment of celsian ceramics from fly ash useful for X-ray radiation-shielding application
No full textFor the first time the capability of fly ash to produce barium containing radiopaque materials has been demonstrated. Fly ash which is a waste generated in power plants due to combustion of pulverized coal, has been utilizeda for making X-ray radiation-shielding materials. A novel method for making radiation-shielding materials utilizing fly ash and barium compound has been developed by ceramic processing route using phosphate bonding. The fly ash based radiopaque materials (FARM), i.e. shielding materials are characterized for their X-ray attenuation characteristics. The shielding, i.e. half value thickness (HVT) for different energies of X-ray photons for FARM have been computed and compared with conventionally used shielding materials, namely concrete and lead, it is found that the HVT of the fly ash based shielding materials, in comparison to concrete, is significantly very less for the various energies of X-ray photons.\ud
\ud
The X-ray powder diffraction studies confirmed the presence of monoclinic and hexagonal celsian and sanbornite as the major shielding phases and potassium aluminosilicate, sodium aluminosilicate and silicophosphate as the binder phases in the FARM and are responsible for providing bonding to the ceramic matrix leading to the effective shielding and mechanical properties. Scanning electron microphotographs have revealed the compacted plate like particles with hexagonal morphological characteristics of the various barium silicate and barium aluminosilicate (BAS) shielding phases in the matrix of radiopaque materials. The mechanical properties, namely compressive strength and impact strength evaluation test showed that FARM meets the standard specifications laid down for radiation-shielding concrete and ceramic tiles. Based on the above studies, it is found that FARM, can preferably be used for the construction of X-ray diagnostic and CT-scanner room to provide adequate shielding against X-ray photons
Effects of State Change of Liquid Crystalline Polymer on Dynamic Visco-Elasticity of its Blends with Polyethylene-Terephthalate
No full textThe dynamic viscoelastic properties of liquid crystalline polymer (LCP) and polyethylene terephthalate (PET)\ud
blends were studied at two different temperatures: 265°C at which LCP was in solid state and 285°C at which LCP was in molten state. The PET was in molten state at both the temperatures. The storage modulus, G’, loss modulus, G’’, dynamic viscosity, h’, of blends with different compositions were evaluated and compared. The morphology of these samples was studied using scanning electron microscope, which exhibited composition dependency. A maxima was observed in the viscosity versus composition plot corresponding to 90/10 LCP/PET blend at 285°C. The G’ versus G’’ plots demonstrated the composition dependency of LCP/PET blend
Graphite modified cotton fibre reinforced polyester composites\ud under sliding wear conditions
Get PDFGraphite modified polyester–cotton composites were developed and studied for friction and sliding wear behaviour at different applied loads and graphite concentrations. Sliding wear tests were conducted using pin-on-disc apparatus. The composite pins were tested against EN-31 steel disc. The specific wear rate of polyester reduced on reinforcement of cotton and on addition of graphite. The coefficient of friction of polyester resin increased on cotton reinforcement and reduced significantly on addition of graphite in cotton–polyester composite. The temperature of contact surface reduced on addition of graphite in cotton–polyester composite. The reduction in wear rate of graphite modified polyester–cotton composite has been discussed with the help of scanning electron microscope (SEM) observations of worn surfaces, coefficient of friction and the temperature of contact surface
Thermal Immobilization of Toxic Metals of Industrial Waste with Clay and Fly Ash
No full textWaste generated from galvanizing and metal finishing processes is considered to be a hazardous due to the presence of toxic metals like Pb, Cu, Cr, Zn, etc. Thermal treatment of such types of wastes in the presence of clay and fly ash can immobilizes their toxic metals to a maximum level. After treatment solidified mass can be utilized in construction or disposed off through land fillings without susceptibility of re-mobilization of toxic metals. In the present investigation locally available clay and fly ash of particular thermal power plant were used as additives for thermal treatment of both of the wastes in their different proportions at 850, 900 and 950 degrees C. Observed results indicated that heating temperature to be a key factor in the immobilization of toxic metals of the waste. It was noticed that the leachability of metals of the waste reduces to a negligible level after heating at 950 degrees C. Thermally treated solidified specimen of 10% waste and remaining clay have shown comparatively a higher compressive strength than clay fired bricks used in building construction. Though, thermally heated specimens made of galvanizing waste have shown much better strength than specimen made of metal finishing waste. The lechability of toxic metals like Cr, Cu, Pb and Zn became far below from their regulatory threshold after heating at 950 degrees C. Addition of fly ash did not show any improvement either in engineering property or in leachability of metals from the solidified mass. X-ray diffraction (XRD) analysis of the solidified product confirmed the presence of mixed phases of oxides of metals.\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\ud
\u
Development of Celsian Ceramics from Fly Ash Useful for X-Ray Radiation Shielding Applications
No full textFor the first time the capability of fly ash to produce barium containing radiopaque materials has been demonstrated. Fly ash which is a waste generated in power plants due to combustion of pulverized coal, has been utilizeda for making X-ray radiation-shielding materials. A novel method for making radiation-shielding materials utilizing fly ash and barium compound has been developed by ceramic processing route using phosphate bonding. The fly ash based radiopaque materials (FARM), i.e. shielding materials are characterized for their X-ray attenuation characteristics. The shielding, i.e. half value thickness (HVT) for different energies of X-ray photons for FARM have been computed and compared with conventionally used shielding materials, namely concrete and lead, it is found that the HVT of the fly ash based shielding materials, in comparison to concrete, is significantly very less for the various energies of X-ray photons.\ud
\ud
The X-ray powder diffraction studies confirmed the presence of monoclinic and hexagonal celsian and sanbornite as the major shielding phases and potassium aluminosilicate, sodium aluminosilicate and silicophosphate as the binder phases in the FARM and are responsible for providing bonding to the ceramic matrix leading to the effective shielding and mechanical properties. Scanning electron microphotographs have revealed the compacted plate like particles with hexagonal morphological characteristics of the various barium silicate and barium aluminosilicate (BAS) shielding phases in the matrix of radiopaque materials. The mechanical properties, namely compressive strength and impact strength evaluation test showed that FARM meets the standard specifications laid down for radiation-shielding concrete and ceramic tiles. Based on the above studies, it is found that FARM, can preferably be used for the construction of X-ray diagnostic and CT-scanner room to provide adequate shielding against X-ray photons
Dry sliding wear response of a Zn-based alloy con6taining 37.5 % al as affected by sliding conditions.
No full textThis paper discusses the observations made pertaining to dry sliding wear characteristics of a Zn-based alloy at different sliding speeds and pressures. The wear rate increased with speed and pressure. The wear rate versus pressure plots attained two slopes wherein the slope was low up to a specific pressure followed by an increased slope at still higher pressures. This trend was observed at all the sliding speeds except the maximum; in the latter case one slope (identical to that of the higher slope at the lower speeds) only was noted. The seizure pressure was noted to decrease with speed. The temperature near the specimen surface increased with test duration, pressure and sliding speed. The rate of temperature increase was significantly high initially. This was followed by a lower rate of increase in temperature at longer test durations. In some cases, the rate of temperature increase became high once again towards the end of the tests. The influence of applied pressure and sliding speed on the temperature increase was practically identical to that on wear rate. Lower wear rate of the alloy agreed with less surface/subsurface damage and finer debris formation and vice versa.\ud
\u
Sliding Wear Response of Cast Iron as Influenced by Microstructural Features and Test Condition.
No full textThis study analyzes the effects of material and test parameters on the sliding wear characteristics of a cast iron. Material parameters involved microstructural characteristics in terms of the shape of graphite phase and changing fraction of the matrix constituents like ferrite and pearlite. Factors related to sliding wear conditions selected for the study were applied pressure and test environment in terms of the presence of an oil lubricant and two different concentrations of graphite particles suspended in the oil. The microstructure of the cast iron in one case revealed spheroids of graphite in a matrix of mainly ferrite with a limited quantity of pearlite; this material would be referred to as spheroidal graphite iron (SGI) in the subsequent text. On the contrary, flakes of graphite were observed and the matrix comprised mainly pearlite plus a limited quantity of ferrite in the other case to be referred to as gray cast iron (GCI) now onwards. Better wear resistance of GCI in dry, oil and oil plus 5% graphite lubricated conditions than SGI was attributed to the predominant effect of harder and stronger matrix and flaky graphite having large surface area in the GCI while a reversal in the trend in the oil plus 10% graphite lubricant mixture was thought to be due to the predominantly adverse effect of the increasing concentration of the suspended graphite particles in the lubricant mixture. The wear rate versus pressure plots revealed single slope in dry condition for both the varieties of the cast iron. A similar trend was also noticed for the GCI in oil plus 5% graphite lubricant mixture. Three slopes were noticed in case of the GCI tested in oil. In remaining cases, two slopes were observed. The wear rate increased with pressure. Testing the samples in oil lubricated condition led to improved wear resistance than during dry sliding. Addition of graphite particles to the oil lubricant caused still better wear resistance. Presence of 5% graphite in the oil lubricant improved the wear behaviour to the maximum extent while a further increase in the graphite content to 10% in oil tended to produce a reverse effect but it was still superior to that in the oil-only environment. Frictional heating increased with intermediate sliding distance. The rate of increase was high initially followed by a lower rate of increase at\ud
longer test durations (intermediate sliding distance). In some cases, the rate of increase became larger once again towards the end of the tests. The frictional heating increased with pressure at a low rate initially followed by a higher rate of increase beyond a specific pressure in general. Less frictional heating was observed in the presence of oil while addition of graphite to the oil proved still better, 5% graphite producing minimum frictional heating. The observed response of the samples has been substantiated further through the characteristics of wear surfaces, subsurface regions and debris particles and operating wear mechanisms discussed
Shear Rate Dependence of Viscosity and First Normal Stress Difference of LCP/PET Blends at Solid and Molten States of LCP
Get PDFThe liquid crystalline polymer (LCP) and polyethylene terephthalate (PET) were blended in an elastic melt extruder to make samples having 20, 40, 60, 80, and 100 wt % of LCP. Morphology of these samples was studied using scanning electron microscopy. The steady state shear viscosity (Z), dynamic complex viscosity (Z*) and first normal stress difference (N1) were evaluated and compared at two\ud
temperatures: 2658C, at which LCP was in solid state, and\ud
2858C, at which LCP was in molten state. The PET was in\ud
molten state at both the temperatures. The shear viscosity of the studied blends displayed its dependence on composition and shear rate. A maxima was observed in viscosity versus composition plot corresponding to 80/20 LCP/PET blend. The N1 increased with LCP loading in PET and with the increased asymmetry of LCP droplets. The N1 also varied with the shear stress in two stages; the first stage demonstrated elastic deformation, whereas second stage displayed dominant plastic deformation of LCP droplets