The present study aims to estimate the residence-time of groundwater based on bomb-produced 36 Cl . Water samples were collected from some selected wells located around Al-Zulfi province, Riyadh central region, Saudi Arabia. 36 Cl/Cl ratios in the water samples are determined by Inductively Coupled Plasma Mass Spectrometry (ICPMS) and Liquid Scintillation Counting (LSC). 36 Cl/Cl ratios in the groundwater were estimated to be 1.0–2.0×10 −10 . The shallow unconfined aquifer of the area is mainly replenished by the water infiltration from the seasonal rains. Estimates of residence time were obtained by comparing the measured bomb-derived 36 Cl concentrations in groundwater with the background reference. Dating based on a 36 Cl bomb pulse may be more reliable and sensitive for groundwater recharged before 1975, back as far as the mid-1950s. The above 36 Cl -background concentration was deduced by determining accurately the background corrected Dye-3 ice core data from the frozen Arctic Data, according to the estimated total 36 Cl resources, including bomb-produced 36 Cl fallout. Estimated residence time of 7.81×10 4 y is obtained from extrapolated flow velocity. 36 Cl concentration in groundwater does not reflect the input of bomb pulse 36 Cl , and it belongs to the era before 1950.

 Low level concentration of iodine was determined in various milk products for adult and baby milk powders by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method. It is a reliable method for the determination of iodine in milk samples, using alkaline digestion with potassium hydroxide KOH solution in an oven. After digestion, a stabilizer is added and the solution is taken to volume, then filtered and analysed by ICP-MS either directly or after dilution. Samples for investigation were collected from domestic market. The detection limits of current Iodine not affected by interfering from milk gradient, the minimum detection limit (MDL) of Iodine approaches 10 ppb was achieved. This method showed excellent results for aqueous iodide solutions, although the complex milk digest matrix made the method unsuitable for such samples. So, investigation of the iodine species is achieved through the oxidation and extraction of iodine milk samples, the digestion was carried out to control the iodine chemistry. Iodine concentrations were ranged of 0.17 – 5.1 mg/kg for various samples, the accuracy of the method ranged from 95 to 100%.

In the present work, time dependent availability of a mechanical system i.e., container manufacturing plant is estimated. Here, Mathematical modeling has been developed on the basis of Markov birth-death process using probabilistic approach. The first order governing equations thus formulated using the mnemonic rule is solved to estimate the availability of the system in the transient state. The failure rates and the repair rates of the subsystems are taken constant. Matrix method has been applied to calculate transient state availability of the system up to desired decimal places. The time dependent availability is shown with the help of graph and the parameter MTTF is obtained. Correlation and regression coefficients between time and availability have been computed to study the variation between time and availability. The results obtained in the present work are considered to be very useful for taking all maintenance decisions associated with container manufacturing plant.

In recent years several structures, notable almost contact atructure [2], [6], [8], almost r-contact structure [4],[15], almost paracontact structure [9], almost r-paracontact structure [2], almost contact hyperbolicstructure [14] and almost r-contact hyperbolic structure [5] have been defined and studied on a differentiable manifold by many geometers. Some generalized structures, including almost ) ,( 2 1 ee contact structure [10], almost ) ,( 2 1 ee -r-contact structure [11], [12] and unified structure [1], [13] have also been defined. In this paper, We define and study a compendious structure having the following structures as its special cases.