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Home > A Study of Mechanical Properties of Irradiated Titanium and its Alloys at Low Temperatures

A Study of Mechanical Properties of Irradiated Titanium and its Alloys at Low Temperatures

Thesis Info

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Author

Haider, Syed Karrar

Program

PhD

Institute

University of the Punjab

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2009

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1503

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725413459

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The present work attempts to study the effects of irradiation and deformation temperature on the mechanical properties of polycrystalline pure titanium (99.994 %). The specimens were irradiated by electron beam of energies ranging from 8-18 MeV at 300 K. The irradiated and unirradiated specimens were deformed using Universal Testing Machine in the temperature range 300-100 K at a strain rate of 1.2 ´ 10-3 /sec. A comparison between stress strain curves of unirradiated/ irradiated specimens recorded through the attached machine at room temperature, was carried out. The yield stress and ultimate tensile stress of irradiated specimens were found to be higher than that of unirradiated ones however the ductility was found to decrease. The changes in tensile parameters became more pronounced with increase of irradiation energy and decrease of test temperature. The stress relaxation tests were also conducted to observe stress relaxation behavior of the material at a certain fixed load. The stress relaxation rate was found to be lower in irradiated specimens than that of unirradiated ones lowering of test temperature and enhancing of irradiation energy. The activation parameters of stress relaxation like activation energy and activation volume were also analyzed from the relaxation tests. The activation energy was found to increase with decrease of test temperature and with increase of incident irradiation energy. The analysis of activation energy (U0) and activation volume (Vσ) suggests that the initial plastic deformation in irradiated titanium specimens is controlled by the interaction of dislocations with irradiation induced defects while this advances into dislocation-dislocation intersection as the deformation i proceeds which seem to control the rate process in irradiated polycrystalline titanium. Scanning electron microscope micrographs of the fractured surfaces show a combination of ductile and cleavage fractures, corresponding to different values of irradiation energy and test temperature.
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54. Al-Qamar/The Moon

54. Al-Qamar/The Moon

I/We begin by the Blessed Name of Allah

The Immensely Merciful to all, The Infinitely Compassionate to everyone.

54:01
a. The Last Hour has drawn near,
b. and the moon has been split open.

54:02
a. But whenever they see a Sign, they turn away, and mock:
b. Just the ‘same old deception, continuing!’

54:03
a. And they belie it and follow their whims.
b. But every matter will reach its proper end - so they will know the truth.

54:04
a. Certainly enough of the narratives of the fate of the former disbelieving nations would have
already come in which there is deterrence,

54:05
a. narratives full of far reaching wisdom,
b. yet the warnings do not benefit them.

54:06
a. So turn away from them.
b. The Time is going to come when the Caller will call all people to a horrible event;

54:07
a. with their eyes humbled, they will emerge out of their graves as if they were swarms of locust, looking confused and bewildered,

54:08
a. scrambling in a stampede and rushing towards the Caller.
b. The disbelievers will say remorsefully:
c. ‘This is such a difficult time!’

54:09
a. Before them the People of Noah too had belied OUR Messages and Messenger,
b. and they belied OUR servant Noah, and alleged:

c. ‘He is insane!’
d. And he was rebuked and prevented from advocacy.

54:10
a. So he appealed to his Rabb - The Lord in utter helplessness:
b. ‘I have certainly been overpowered.
c. So help’ me!

Cytotoxic Assessment of Quinoline Based Derivatives on Liver Cancer Cell Line Quinoline compounds and their Cytotoxicity

Current scenario of newer diseases with multiple causes has drawn the attention of the researchers in the field of therapeutics and they are now inclined to identify molecules effective for targeted therapy. Objective: Quinoline (1-azanaphthalene); belongs to heterocyclic aromatic nitrogen compound. Some quinoline-based derivatives are also known for their anti-tumor activity. The study was planned to evaluate the cytotoxic potential of quinoline derivatives. Methods: Berberine; a quinoline compound was made part of study to make structural analogs which were docked against potential target proteins. Cytotoxic profiling of all derivatives was done using MTT cytotoxicity assay. Results: The pharmacoinformatic and structure activity relationship studies of analogs were done. The cytotoxic profiles were elucidated by comparing viability rates of analogs treated hepatic cancerous cell line with untreated hepatic cells and untreated mesenchymal stem cells as standards.  Marked cytotoxicity was seen in all molecules at low doses than reported in past studies with relevance to parent compound. Conclusions: The results will be further confirmed through various other cell culture assays targeting different marker proteins, pharmacoinformatics tools and structure activity relationship studies

Fabrication and Characterization of Ago, Sno2 and Tio2 Nanoparticles for Multiple Applications

This study was designed to synthesize AgO, SnO2 and TiO2 nanoparticles via both green and chemical methods (precipitation and sol-gel methods). The Daphne alpina leaves extract was used as reducing agent in the green process, while comparatively less toxic reducing agents (C4H11NO for C-AgO, C3H8O for C-SnO2 and ETOH for C-TiO2) were used in the chemical methods. After successful synthesis, the physiochemical properties of the nanoparticles were traced by BET surface area measurement by N2 adsorption-desorption method, X-ray diffraction (XRD), energy dispersive X-rays (EDX) spectroscopy, scanning electron microscopy (SEM), thermogravimetric and differential thermogravimetric (TG/DTG) analysis, diffuse reflectance spectroscopy (DRS) and fourier transform infrared (FTIR) spectroscopy. These analytical techniques further confirmed the successful synthesis of all the desired nanoparticles. XRD confirmed the mixed geometrical phase (cubic and hexagonal) of silver oxides nanoparticles. Both the tin dioxide (G-SnO2 and C-SnO2 NPs) nanoparticles have cassiterite mineral phase with tetragonal geometry while the titanium dioxide nanoparticles (G-TiO2 and C-TiO2 NPs) have anatase mineral phase with tetragonal geometry. The nanoparticles synthesized by green method have high surface area as compared to their analog prepared by chemical methods. The SnO2 and TiO2 nanoparticles synthesized by green (G-SnO2 and G-TiO2 NPs) and chemical (C-SnO2 and C-TiO2 NPs) methods were used as adsorbent for the adsorption of cadmium ions (Cd2+). The Batch method was applied for the Cd2+ ions adsorption process at pH 4 and 6, while temperature was ranging from 293 to 323 K. The NaNO3 was used as xx background electrolyte while the Cd2+ ions concentrations were ranging between 10-100 ppm. The equilibrium concentration of Cd2+ ions was measured by atomic absorption spectrometer (AAS). The Langmuir model was applied to determine the maximum sorption capacity (Xm) and binding energy constant (Kb). A set of equations were used to determine Cd2+ sorption mechanism and also calculated the changes in enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG). The effect of temperature was more pronounced on Kb values as compared to Xm values, the increase in Kb values with temperature suggest that the adsorption process was thermodynamically favored. The decrease in the ΔG with increase in pH and temperature proposed that the adsorption process was more spontaneous at high pH and temperature. All the synthesized metal oxides (MO NPs) nanoparticles by green (G-AgO, G-SnO2 and G-TiO2 NPs) and chemical method (C-AgO, C-SnO2 and C-TiO2 NPs) were used a photocatalysts for the degradation of rhodamine 6G. The degradation rate constant was calculated by applying pseudo first order reaction. Both titanium dioxide (G-TiO2 and C- TiO2 NPs) have high photocatalytic activity compared to tin dioxide (G-SnO2 and C- SnO2 NPs) and silver oxide (G-AgO and C-AgO NPs). The AgO and SnO2 NPs fabricated by using both the green and chemical methods were functionalized with moxifloxacin using sonochemical method. Both the pure and moxifloxacin functionalized nanoparticles were screened against the selected microbial strains. The Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger are the selected microorganisms used during xxi antimicrobial study. The both silver oxide synthesized by green and chemical methods and its moxifloxacin functionalized analog have high antimicrobial activity as compared to tin dioxide (G-SnO2 and C-SnO2 NPs) and its functionalized analog (MG-SnO2 and MC-SnO2 NPs). The moxifloxacin functionalized have positive effect on the antimicrobial activity of both silver oxides (G-AgO and C-AgO NPs) and in dioxide nanoparticles (G-SnO2 and C-SnO2 NPs).