Search

Laser Induced Breakdown Spectroscopy (LIBS) technique for the detection of carcinogenic metals in gallbladder stones samples was developed. We have studied the effect of the laser pulse energy and the delay time dependence on LIBS signal intensity. The constituting elements present in the test samples were identified by using the finger prints wavelength of elements of interest using NIST database. The detected carcinogenic metals were Cd, Ni, Cr, Pb and Hg. The plasma temperature and the electron density were also determined to check for the local thermal equilibrium conditions for the laser induced plasma generated by focusing the laser beam on gall bladder samples.

The harmful health effects of nicotine, carbon monoxide and other noxious gases due to tobacco smoke are well known. However there is no systematic study reported regarding the detection of heavy and trace metals such as cadmium, lead, arsenic present in the periodontium due to heavy tobacco smoking. Hence there is high demand to develop a reliable, fast and in situ technique for detection of these elements which have injurious effects on smoker's teeth in general and health in particular. This study aimed to compare between the clinical periodontal parameters of smokers versus non-smokers and measure the concentration of above mentioned toxic elements present in root surfaces of the extracted teeth from each group. Sixty extracted teeth from patients having history of chronic periodontitis were divided into two groups 30 teeth each according to smoking habits (Smoker or non smoker group) and another 30 extracted teeth from non smoking patients who didn't have history of chronic periodontitis were considered as controls. Gingival index (GI), plaque index (PI), clinical attachment loss (CAL) and probing pocket depth (PD) were recorded and after extraction of the affected teeth, chemical analysis was conducted using laser induced breakdown spectroscopy (LIBS) technique developed recently at our laboratory. The increased lead levels on root surfaces of periodontally diseased teeth in smokers explained the increased CAL and periodontal destruction in these cases. Toxic elements like cadmium and arsenic were detected in teeth of both smoker and non-smoker group which may be due to contamination from the outside environment and bad dental hygienic conditions.

A highly sensitive Laser Induced Break down Sensor has been developed using a fourth harmonic Nd: YAG laser and a spectrograph with an ICCD camera to detect carcinogenic substances in cosmetic products especially hair dyes and Kohl available on the local market with in Saudi Arabia. For the hair dye, chromium (Cr) was detected using a spectral marker line of 427.5 nm and concentrations in the range of 5-11 ppm were detected by the LIBS sensor with a detection limit of 1.2 ppm. For Kohl eyeliners lead (Pb) and chromium (Cr) was detected using atomic transitions at wavelengths of 405.7 nm and 425.4 nm respectively as the spectral marker lines. Lead (Pb) and chromium (Cr) was detected in the concentration range of 5-14 ppm and 4-9 ppm with detection limits of lppm and 2 ppm respectively.

Pulsed laser ablation in liquids is a simple synthesis process of nano-particles for the production of high purity material with no need for any expensive instrumentation except laser. The 532 nm wavelength laser beam with 5 ns pulse width and 10 Hz repetition rate was an ablating laser source. In order to control the size and stoichiometry of the nano particles, the laser ablation was done in the presence of 9% of H2O2. The optical properties and structure of the prepared samples were studied using different analytical techniques, such as energy dispersive X-ray spectroscope (EDS), X-ray Diffraction, UV-Visible absorption, Photoluminescence, FT-IR. In order to study the morphology of the prepared nano-sized powders, Field Emission Scanning Electron Microscope was used. From the above analytical studies it was found that the particle size was between 13 and 28 nanometer, while the band gap energy was estimated to be 2.46 eV.

We present a facile method for fabrication of Titania (TiO2) based superhydrophobic surfaces by silanization with wettability switching from superhydrophobic to superhydrophilic under ultraviolet (UV) light irradiation. The dynamic of surface wettability under UV irradiation was tested under ambient environment as well as in oily environment. We synthesized TiO2 based superhydrophobic surface with contact angle as high as 154° for advancing angle and 152° for receding angle in air. A dramatic decrease of the contact angle to 0° was observed when the TiO2 sample was irradiated with UV light. No appreciable change in contact angle was observed when sample was tested under oily medium. However, a switching from Cassie state to Wenzel state was occurred, resulting in a sticky superhydrophobic surface. Photocatalyic activity induced in organic degradation was probably the major cause of the wettability switching.

Laser induced breakdown spectroscopy (LIBS), is an atomic emission based analytical technique, where laser induced plasma is analyzed after appropriate time delay allowed for plasma cooling. The selectivity and the sensitivity of the system immensely depend on the plasma parameters and hence understanding the formation and evolution of the laser induced plasma is very vital in the optimization of LIBS detection systems. In this study, laser induced plasma was generated using a laser beam of 266 nm wavelength and spectral analysis was carried out using Spectrograph ICCD system with appropriate time delay. The temporal response of the plasma existing in local thermodynamic equilibrium was investigated with respect to the important plasma parameters (temperature and electron density) computed from the LIBS spectra.

Nano structured metal oxides (WO 3 and ZnO) were synthesized and impregnated with a noble metal palladium and it was found from the absorption spectra that the band gap energies of the palladium doped material revealed blue shifts compared to the band gap energies of their pure counterparts. Pure and doped material synthesized were used as a photo-catalyst in the presence of 355 nm UV laser radiation in the process of deactivation of Escherichia coli micro organism in water and it is observed that the doped material show a considerable enhancement of the deactivation process with higher bacteria decay rate constant and shorter depletion time, which is related to the widened band gap due to palladium doping.

Nano NiO photo catalyst was synthesized by sol gel method and it is used as a photo catalyst in conjunction with 355 nm laser radiation in the process of disinfecting water infected with Escherichia coli microorganism. When synthesized nano-NiO material is used as a photo catalyst, a bacteria decay rate constant of 0.35 min-1 and this rate constant is higher than the bacteria decay rate constant of 0.24 minutes−1 for TiO 2 as a photo catalyst under same catalytic concentration and laser pulse energy. From the TEM study, a grain size as low as 20–40 nm was observed and the absorption study showed a band gap of 3.85 eV. The dependence of depletion rate of bacterial count in the infected water on the nano-NiO concentration and the irradiating laser pulse energy were carried out.

This study provides the causes of underground power cables failures in the Eastern region of Saudi Arabia have been investigated. The major cause for these outages has been identified as the quality of cable, play major role in these outages. Due to moisture in the soil across red sea and Arabian region, the cables outages problem is aggravated. This is due to water penetration into the plastic insulated multi-conductor cables which can seriously effect the electrical properties of such devices/or conductors. The problem of water penetration is amplified when the cable is positioned underground or in a high humidity environment. The impurities of ionic species like Na, Mg, K in the insulating layer of cables under moisturized soil could enhance the tree formation process and could cause breakdown between conducting part and the earth. A laser senor based on laser-induced breakdown spectroscopy (LIBS) principle was developed for the measurement of sodium and chlorine which exist in cables and those impurities responsible for absorption of water and water tree formation. For quality testing of different kinds of cables manufactured in the Kingdom of Saudi Arabia of various samples such as faulted cables, new manufactured and even the raw materials like PVC used for insulation were analyzed by using the LIBS. For spectroscopic analysis of cables the plasma was generated by focusing a pulsed Nd: YAG laser at 1064 nm (1 J, 8 ns, 10 Hz) on the polymer cable samples. The LIBS results were compared with the results obtained using standard analytical technique such as inductively coupled plasma emission spectroscopy (ICP). The relative accuracy of our LIBS system for various elements as compared with ICP method is in the range of 0.03–0.6 at 2.5% error confidence.

Saudi electric Company (SEC), and Petrochemical industries in Saudi Arabia and other plants provide the utilizing location and testing, and also some of the raw insulation materials for cable industries. Major petrochemical producers are striving to improve the quality of the plastic raw materials. On the other hand, cable industry has also made noticeable progress in the production of distribution voltage level cables; however, many factors are not accounted in the choice of the cable materials. These factors include the quality assurance in manufacturing processes, quality of materials used, weather, and soil environment of the kingdom, and other factors. Underground cables utilizing utility and industries are concerned about the overload and ampacity selected and temperature is, in general, the prevailing stresses producing insulation aging. Also concerned about water penetration of insulated electrical devices and especially plastic insulated multi-conductor cables which can seriously effect the electrical properties of such devices/or conductors. The problem of water penetration is amplified when the electrical cable is positioned underground or in a high humidity environment. This paper presents investigates outages records available to determine some conclusions and what causes such outages. A selection of faulted cables samples, new manufactured are tested by the application of laser based technique. The quality of such cables samples was based on measurement to trace metals present in cables responsible for absorption of water and water tree formation.

Summary form only given. Methane gas is available as a cheap source for heating purposes as well as for converting into higher hydrocarbons using steam reforming and other processes to produce syn-gas. Research has been directed towards the development of alternative techniques to convert methane into more valuable hydrocarbons such as ethylene and propylene as well as for generation of hydrogen. Hydrogen is forecast to become the major source of energy in future. Molecular hydrogen is a clean burning fuel and can be stored as liquid or gas. The ethylene and propylene are raw materials for producing polyethylene and polypropylene and the demand for these polymers is increasing at an immense growth rate. In spite of many research programs, there is no direct conversion process so far reported which is capable of large scale production of these products from methane which could be described as high yield and highly selective process. At present, there are three different photochemical-process based techniques, which have been used for methane conversion with some degree of success. These include UV light, plasma and microwave irradiation in the presence of different catalyst. To the best of our knowledge, there is no report on photodissociation of methane at 355 nm. The aim of the present study is to develop a technique for direct conversion of methane into hydrogen and higher hydrocarbon and to analyze the regenerated products as a result of laser-photodissociation.