Papers by Mohammed A Gondal
A laser sensor based on Laser Induced Breakdown Spectroscopy (LIBS) was developed for analysis of... more A laser sensor based on Laser Induced Breakdown Spectroscopy (LIBS) was developed for analysis of human gallbladder stones specifically for determination of heavy metals. In addition to qualitative analysis, the concentrations of the heavy metals were determined in different gallbladder stones samples using LIBS technique for the spectral lines of Cr I at 425.4 nm, Pb I at 368.3 nm, Cd I at 291.5, Ni at I 361.9 nm and Hg I at 366.3 respectively. The limit of detection of our LIBS system was determined as well for these five elements. The concentrations of above mentioned elements detected with Our LIBS system were in good agreement with ICP-results. In addition, the plasma parameters like temperature and electron density were also estimated using the so called Boltzmann plot and Boltzmann distribution of upper energy levels and Stark broadening, respectively. The plasma temperature and electron density data for gallbladder stones was essential to testify that the laser induced plasm...
Scientific Reports, 2017
A facile synthesis method for highly stable carbon nanoparticle (CNP) dispersion in acetone by in... more A facile synthesis method for highly stable carbon nanoparticle (CNP) dispersion in acetone by incomplete combustion of paraffin candle flame is presented. The synthesized CNP dispersion is the mixture of graphitic and amorphous carbon nanoparticles of the size range of 20–50 nm and manifested the mesoporosity with an average pore size of 7 nm and a BET surface area of 366 m2g−1. As an application of this material, the carbon nanoparticle dispersion was spray coated (spray-based coating) on a glass surface to fabricate superhydrophobic (water contact angle > 150° and sliding angle < 10 °) surfaces. The spray coated surfaces were found to exhibit much improved water jet resistance and thermal stability up to 400 °C compared to the surfaces fabricated from direct candle flame soot deposition (candle-based coating). This study proved that water jet resistant and thermally stable superhydrophobic surfaces can be easily fabricated by simple spray coating of CNP dispersion gathered ...
Scientific reports, Jan 10, 2017
Superhydrophilic and underwater superoleophobic surfaces were fabricated by facile spray coating ... more Superhydrophilic and underwater superoleophobic surfaces were fabricated by facile spray coating of nanostructured WO3 on stainless steel meshes and compared its performance in oil-water separation with ZnO coated meshes. The gravity driven oil-water separation system was designed using these surfaces as the separation media and it was noticed that WO3 coated stainless steel mesh showed high separation efficiency (99%), with pore size as high as 150 µm, whereas ZnO coated surfaces failed in the process of oil-water separation when the pore exceeded 50 µm size. Since, nanostructured WO3 is a well known catalyst, the simultaneous photocatalytic degradation of organic pollutants present in the separated water from the oil water separation process were tested using WO3 coated surfaces under UV radiation and the efficiency of this degradation was found to be quite significant. These results assure that with little improvisation on the oil water separation system, these surfaces can be ma...
Nature Communications, 2017
Photoresponsive titania surfaces are of great interest due to their unique wettability change upo... more Photoresponsive titania surfaces are of great interest due to their unique wettability change upon ultraviolet light illumination. However, their applications are often limited either by the inability to respond to visible light or the need for special treatment to recover the original wettability. Sensitizing TiO2 surfaces with visible light-absorbing materials has been utilized in photovoltaic applications. Here we demonstrate that a dye-sensitized TiO2 surface can selectively change the wettability towards contacting liquids upon visible light illumination due to a photo-induced voltage across the liquid and the underlying surface. The photo-induced wettability change of our surfaces enables external manipulation of liquid droplet motion upon illumination. We show demulsification of surfactant-stabilized brine-in-oil emulsions via coalescence of brine droplets on our dye-sensitized TiO2 surface upon visible light illumination. We anticipate that our surfaces will have a wide rang...
Journal of Advanced Oxidation Technologies, 2015
Bismuth oxybromide (BiOBr) has attracted a resurgence of interest due to the outstanding visible ... more Bismuth oxybromide (BiOBr) has attracted a resurgence of interest due to the outstanding visible light driven photocatalytic performance, which has been widely reported. However, its photosensitization degradation performance of methyl orange (MO) is limited possibly caused by low negative LUMO (lowest unoccupied molecular orbitals) level of MO molecules. The work presented here deals with the improved photodegradation behavior of methyl orange molecules onto BiOBr in the presence of Rhodamine B (RhB, as photosensitizer) through a semiconductor-mediated process. It was found that MO could be photodecomposed much effectively under the assistance of RhB molecules from aqueous solution. The photosensitization process which occurred between RhB and BiOBr is of photochemical origin and responsible for the boosted photodegradation behavior towards MO, which strongly depends on the irradiation time, BiOBr dosage and concentration of model contaminant (MO) and photosensitizer (RhB).
Journal of Environmental Science and Health, Part B, 2016
Laser induced breakdown spectroscopy (LIBS) was applied for the detection of carcinogenic element... more Laser induced breakdown spectroscopy (LIBS) was applied for the detection of carcinogenic elements like bromine in four representative brands of loaf bread samples and the measured bromine concentrations were 352, 157, 451, and 311 ppm, using Br I (827.2 nm) atomic transition line as the finger print atomic transition. Our LIBS system is equipped with a pulsed laser of wavelength 266 nm with energy 25 mJ pulse(-1), 8 ns pulse duration, 20 Hz repetition rate, and a gated ICCD camera. The LIBS system was calibrated with the standards of known concentrations in the sample (bread) matrix and such plot is linear in 20-500 ppm range. The capability of our system in terms of limit of detection and relative accuracy with respect to the standard inductively coupled plasma mass spectrometry (ICPMS) technique was evaluated and these values were 5.09 ppm and 0.01-0.05, respectively, which ensures the applicability of our system for Br trace level detection, and LIBS results are in excellent agreement with that of ICPMS results.
Lasers in medical science, Jan 17, 2016
Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique with numerous adv... more Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique with numerous advantages such as rapidity, multi-elemental analysis, no specific sample preparation requirements, non-destructiveness, and versatility. It has been proven to be a robust elemental analysis tool attracting interest because of being applied to a wide range of materials including biomaterials. In this paper, we have performed spectroscopic studies on gallstones which are heterogeneous in nature using LIBS and wavelength dispersive X-ray fluorescence (WD-XRF) techniques. It has been observed that the presence and relative concentrations of trace elements in different kind of gallstones (cholesterol and pigment gallstones) can easily be determined using LIBS technique. From the experiments carried out on gallstones for trace elemental mapping and detection, it was found that LIBS is a robust tool for such biomedical applications. The stone samples studied in the present paper were classified u...
Applied Radiation and Isotopes, 2015
Pulse height tests of 100 mm  100 mm cylindrical fast LaBr 3 :Ce detector. Prompt gamma ray meas... more Pulse height tests of 100 mm  100 mm cylindrical fast LaBr 3 :Ce detector. Prompt gamma ray measurements. Water samples with mercury (3.1 wt%), boron (2.5 wt%), cadmium (0.25 wt%), chromium (52 wt%), and nickel (22 wt%) contamination.
Scientific Bases for the Preparation of Heterogeneous Catalysts - Proceedings of the 10th International Symposium, Louvain-la-Neuve, Belgium, July 11-15, 2010, 2010
Nano palladium-loaded on nano tungsten trioxide (n-Pd/n-WO3), with 10% wt Pd loading, was prepare... more Nano palladium-loaded on nano tungsten trioxide (n-Pd/n-WO3), with 10% wt Pd loading, was prepared by the impregnation evaporation method. The n-WO3 support was prepared by dehydration of tungstic acid (H2WO4). The n-Pd/n-WO3 was characterized by Raman spectroscopy, X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). This material was tested as a photocatalyst for inactivation and killing of coliform bacteria,
Optics & Laser Technology, 2012
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013
Journal of Spectroscopy, 2013
Nitrogen concentration was measured via 2.52 MeV nitrogen gamma ray from melamine, caffeine, urea... more Nitrogen concentration was measured via 2.52 MeV nitrogen gamma ray from melamine, caffeine, urea, and disperse orange bulk samples using a newly designed D-D portable neutron generator-based prompt gamma ray setup. Inspite of low flux of thermal neutrons produced by D-D reaction-based portable neutron generator and interference of 2.52 MeV gamma rays from nitrogen in bulk samples with 2.50 MeV gamma ray from bismuth in BGO detector material, an excellent agreement between the experimental and calculated yields of nitrogen gamma rays indicates satisfactory performance of the setup for detection of nitrogen in bulk samples.
IEEE Photonics Journal, 2013
Talanta, 2004
A photoacoustic (PA) spectrometer with high selectivity and sensitivity has been developed for tr... more A photoacoustic (PA) spectrometer with high selectivity and sensitivity has been developed for trace gas analysis and for the detection of gas leak at part per trillion by volume (pptV) level. This PA system comprises of a resonant photoacoustic cell, a pulsed line tunable CO 2 laser as an excitation source and a sensitive electret microphone as a photoacoustic detector with an option to trigger the safety alarm system for early warning of gas leaks. In this work, three resonant PA cells with various geometries have been developed at our laboratory for the detection of photoacoustic signal using pulsed laser system and their comparative performance have been studied. As a special application of this PA system, the detection of sulfur hexa fluoride (SF 6) gas using these three cells has been carried out for optimizing the sensitivity. Besides this, our PA system can very well be applied for pollution monitoring and detection of hazardous gases in a noisy environment.
Polyhedron, 2009
New copper (I) mixed-ligand complexes 1–4 of the formula Cu (N–N) PR3X, where N–N= 1, 10-phenanth... more New copper (I) mixed-ligand complexes 1–4 of the formula Cu (N–N) PR3X, where N–N= 1, 10-phenanthroline (phen), 2, 2′-bipyridine (bpy), 5, 5′-dimethyl-2, 2′-bipyridine (5, 5′ dimbpy) and PR3= tricyclohexylphosphine, tris (2-cyanoethyl) phosphine and ...
Molecular Physics, 2012
Emission from the lowest quintet state of CO is observed in low power glow discharge. Intersystem... more Emission from the lowest quintet state of CO is observed in low power glow discharge. Intersystem crossing from the state to the state makes transition from the state to lower lying states possible. The term values for the three lower vibrational levels of the state are found to be , and above the ground level. The fundamental vibrational frequency of
Journal of Radioanalytical and Nuclear Chemistry, 2012
A thermal neutron capture-based Prompt Gamma ray Activation Analysis setup has been designed to a... more A thermal neutron capture-based Prompt Gamma ray Activation Analysis setup has been designed to analyze the elemental concentration of environmental bulk samples using a D(d,n) reaction-based portable neutron generator. The performance of the setup was tested through mercury concentration measurements in Hg-contaminated water samples using a large volume cylindrical bismuth germinate (BGO) gamma ray detector. Excellent agreement of experimental count rate of 2.64, 3.19 ? 3.29 and 4.67-5.05 MeV Hg prompt gamma rays with theoretical count rate obtained through Monte Carlo simulations, indicates excellent performance of the newly designed portable neutron generator-based PGNAA setup.
Journal of Nanoparticle Research, 2013
Uniform well-crystallized flower-like BiOI nanoplates contained 3.7 nm mesopores, which may be at... more Uniform well-crystallized flower-like BiOI nanoplates contained 3.7 nm mesopores, which may be attributed to the internanosheet spaces of BiOI with maximum pore diameters of about 30 nm, were successfully synthesized via a simple ethylene glycolassisted solvothermal method. The as-prepared porous BiOI nanoplates exhibited excellent adsorption ability, and the saturated extent of adsorption of BiOI over an RhB solution was as high as 197 mg/g, which is much higher than those for BiOCl and BiOBr prepared via the same method and with a similar surface area. The probable adsorption mechanism could have originated from the interaction between the I atom in BiOI and a proton in RhB at different pH values and temperatures. With visible light irradiation (k [ 420 nm), 80 % of the RhB was degraded in 4 h, while BiOI still demonstrated reasonably outstanding photocatalytic ability under green light (k = 550 ± 15 nm) because of its low-energy gap (1.72 eV). The degradation test for BiOI under irradiation at k = 550 ± 15 nm is an excellent achievement for field applications because the catalyst can be applied in solar irradiation to remove organic pollutants, which may be of great value BiOI complex.
Journal of Materials Processing Technology, 2005
HVOF coating is one of the protective coatings of metallic materials. The mechanical locking is t... more HVOF coating is one of the protective coatings of metallic materials. The mechanical locking is the mechanism for bonding the splats onto the substrate material surface. Thermal integration of coating to the base material through melting and re-solidification is short coming in HVOF thermal spraying process. In the present study, thermal integration of HVOF coating via laser melting is considered. Inconel 625 powders are sprayed onto mild steel samples. The mechanical properties of laser treated and untreated-coatings are examined through threepoint bending tests. It is found that elastic limit of coating reduces after the laser treatment. The defect sites at coating-base material interface are the origin of the crack sites. Moreover, some locally distributed splats with high oxygen content are also act as crack initiation centers.
Journal of Materials Engineering and Performance, 2004
Laser shock processing is a good candidate for surface industry due to its rapid processing, loca... more Laser shock processing is a good candidate for surface industry due to its rapid processing, localized ablation, and precision of operation. In the current study, laser shock processing of steel was considered. The numerical solutions for temperature rise and recoil pressure development across the interface of the ablating front and solid are presented. The propagation of elastic-plastic waves in the solid due to recoil pressure loading at the surface is analyzed and numerical solution for the wave propagation was obtained. An experiment was conducted to ablate the steel surfaces for shock processing. Scanning electron microscopy was carried out to examine the ablated surfaces shock processing while transmission electron microscopy was conducted to obtain dislocation densities after the shock processing. It was found that surface hardness of the workpiece increased in the order of 1.8 times of the base material hardness, and the dislocation was the main source of the shock hardening in the region affected by laser shock processing.
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Papers by Mohammed A Gondal