Search

Effect of 2 MeV Ni+ ion beam irradiation with varying fluences on the surface, structural, and mechanical characteristics of titanium will be explored. For this objective, titanium targets were exposed to nickel ions obtained from a pelletron linear accelerator with 2 MeV energy and various fluences extending from 3 × 1012 to 7 × 1015 ions/cm2. Penetration features and damage evolution of 2 MeV Ni-ion in titanium have been estimated by employing SRIM-2013 software. Various characterization tools were employed to confirm the modifications in the ion beam irradiated targets. The surface and crystallographic variations of ion beam irradiated targets were explored by employing a scanning electron microscope (SEM) and X-ray diffractometer (XRD). Tensile testing and microhardness analysis was performed by utilizing a software-controlled 50 KN universal tensile testing machine and Vickers’s hardness tester, respectively. The SEM analysis represents random and irregularly distributed sputter morphology for lower ion fluences. With the increase of ion fluence, the pores keep growing radially while the growth rate slows down. At the highest ion fluence, localized melting, evaporation and expulsion of surface material were recorded at the irradiated zone. The X-ray diffraction analysis revealed no additional phases to be developed in the Ni-ion treated titanium. However, a variation in the peak intensity and slight angle/position shifting was reported, which depicts the creation of ion-induced stresses and defects. The mechanical testing results indicated the variations in the mechanical characteristics (yield stress, ultimate tensile stress, hardness etc.) of irradiated titanium. The hardness, yield stress and ultimate tensile strength increased monotonically with the increase of ion fluence. The reported modifications in the mechanical characteristics of irradiated titanium are in good accordance with structural and surface modifications. The stated changes in the irradiated titanium are ascribed to the development of ions induced stress as well to creation, augmentation/expansion, recombination, and annihilation of the ion-induced defects.

Contamination of food chain by Polychlorinated biphenyls through use of pesticides, electric and industrial waste poses human health risk. In previous studies, PCB species were stated as endocrine disrupting pollutants and showed toxic health effects like cancerous and noncancerous in animals. The aim of this study was to investigate the levels of PCBs and its toxicity equivalence in food item from plant source to evaluate the health risk in Khanewal and Multan, Pakistan. Samples were collected and processed for further analysis of PCB species through GC/MS after extraction and clean up. The mean concentrations of PCBs ranged as 2.71-151.67 ng/g in beans and grains and 2.30-97.00 ng/g dry weight in vegetables and were lower than 200-3000 ng/g PCBs recommended by FDA tolerance level for all foods. The mean concentrations of two NDL-PCB species detected in all vegetables, beans and grains except

Carcinogenic and health hazard causing heavy metals have been increasing in our dietary stuffs due to large amount of industrial effluents being dumped in water bodies that are ultimately used for irrigation purposes. The study was aimed to assess and compare the mean concentrations of heavy metals (Cd, As and Pb) in soil and vegetables irrigated with four different sources (Ground water, river water, domestic sewage water and industrial untreated effluents and domestic waste water receiving drains) for the estimation of carcinogenic and non-carcinogenic health risk associated with them. Prepared samples were analyzed by through ICP-OES. Statistical analysis revealed that domestic sewage water and drains water usage for irrigation purposes leads to high values of Estimated Daily Intake (EDI) of metals through vegetation. To assess the carcinogenic effects values daily intakes, Total hazard quotients (THQs) and Health indexes (HI), while for carcinogenic effects, Total cancer risks (TCR) were determined. The results of present study revealed that the daily intakes of these metals are far less than that of permissible levels but their bio-accumulating behavior produce high risks to human health. The HI values revealed that waste water usage is producing the vegetables of high health risks. In adults, the HI of

In the present report, MnCr2O4 ceramic oxide has been prepared via the solution based self-combustion sol-gel route sintered at 900 °C. The Rietveld refinement of X-ray powder diffraction profile revealed the single-phase normal spinel structure of the ceramic crystallized in a face-centered cubic unit cell with Fd3m space group symmetry. The field emission scanning electron microscopy exposed well distribution of grains separated by grain boundaries as micro-constituents of the sample. Complex impedance spectroscopy deduced the distribution of relaxation times and thermal activation of charge carriers in the frequency and temperature ranges of 70 − 4 × 10 6 Hz and 543 − 643 K, respectively. The depressed semicircular arcs of the Nyquist plot modeled by an equivalent circuit with configuration R G ׀ ׀ C G + R G B ׀ ׀ C G B confirmed the bulk and interface contribution to the electrical response of the material. The correlated barrier hopping conduction addressed the temperature dependence of frequency exponent after simulation of the AC conductivity data by the equation of Jonscher. The complex modulus study identified the electro-active components of the material and determined the dominant role of grains in the conduction mechanism. The analysis of dielectric constant and loss factor stated thermally activated hopping mechanism of charge carriers between Cr2+ and Cr3+ ions at the octahedral sites of the crystal structure.

Magnesium chromite (MgCr2O4) spinel oxide was synthesized by sol-gel auto-combustion technique. Room temperature X-ray powder diffraction pattern was refined by Fullprof which confirmed the formation of single phase cubic structure with Fd3m space group. The complex impedance spectroscopy was employed to investigate the charge transport mechanism within the temperature range of 423–573K and the impedance data were finely fitted for temperature dependent Nyquist plot to track down the equivalent circuit model [(RGCG)(RGbQGb)]. The temperature and frequency dependent AC conductivity was found to follow Jonscher double power law and the slope of conductivity indicated the correlated barrier hopping (CBH) as a dominant conduction model in the material. The grain and grain boundary polarization was analyzed by electric modulus which confirmed the two phase response of the material. The dielectric relaxation exhibited dispersion in the low frequency region which owed to the interfacial effects.