[en] In order to demonstrate the technical and economic viability of Nuclear Desalination, a small capacity Low Temperature Multi-Effect Distillation (LT-MED) plant is under construction in Pakistan to be coupled with Karachi Nuclear Power Plant (KANUPP), which is a Pressurized Heavy Water Reactor (PHWR) of 137 MWe capacity. The main objectives of this project are to collect the technical and economic data, and to obtain experience in design, manufacturing, operation and maintenance of thermal desalination plants besides generating public acceptance

[en] In this paper, we have reported the influence of annealing treatment on structural, optical, electrical, and thermoelectric properties of MBE-grown ZnO on Si substrate. After growth, a set of as grown ZnO was annealed in oxygen environment at 500–800°C and another set was annealed in different environments (vacuum, oxygen, zinc, and vacuum + zinc) at 600°C for one hour in a programmable furnace. X-ray diffraction (XRD) results demonstrated that all annealed samples exhibited a major diffraction peak related to (002) plane. The full width at half maximum (FWHM) of this plane decreased and crystalline size increased for oxygen annealed sample and it increased when samples were annealed in zinc, vacuum, and successively annealed in vacuum and zinc. Further, photoluminescence spectrum revealed that the intensity of band edge emission increased and defect emission decreased as annealing temperature (oxygen environment) increased while it decreased for rest of annealing ambient. It is suspected that annealing in oxygen environment causes compensation of the oxygen vacancies by the incoming oxygen flux, while annealing in zinc and vacuum generates more oxygen vacancies. Hall and Seebeck measurements are also consistent with these arguments.

[en] Highlights: • Effect of La³⁺ on structural, magnetic and dielectric properties of Cu_0.8Cd_0.2Fe₂O₄ ferrite. • The crystalline size first increased then decreased for further increased of La³⁺ contents. • FTIR spectra reveal two bands that corresponds to tetrahedral and octahedral sites. • Coercivity and Saturation magnetization decease with the concentration of La³⁺ ions. • The frequency dependent dielectric parameters were explained according to Koop,s theory. In this paper, a series of Cu-Cd-La nanostructured ferrites having composition Cu_0.8Cd_0.2Fe_2-yLa_yO₄ (y = 0.000–0.075) was synthesized by co-precipitation technique. The influence of La³⁺ doping on the structural, magnetic and dielectric properties of Cu-Cd ferrite nanoparticles was studied by XRD, FTIR, VSM and Dielectric measurements. Single-phase spinel structure of Cu_0.8Cd_0.2Fe_2-yLa_yO₄ ferrite nanoparticles is confirmed by the x-ray diffraction measurements. It is found that crystalline size increases up to doping concentration y = 0.015 and then decreases for higher concentration of La³⁺ contents in Cu-Cd ferrites. Increase in lattice constant is attributed to larger atomic radius of La³⁺ as compared to Fe³⁺ ion and decrease in lattice constant is attributed to the higher La³⁺ concentration that is linked with the appearance of grain boundaries. FTIR spectra reveal two bands (₁ = 554.18 cm⁻¹ ₂ = 483.49 cm⁻¹) that corresponds to tetrahedral and octahedral sites, respectively, in all the prepared Cu-Cd ferrites. VSM measurements showed that the Coercivity and Saturation magnetization deceases with the concentration of La³⁺ ions. Dielectric parameters tend to decrease at higher frequency and a maximum is observed at a frequency 1.5 × 10⁹ Hz. Dielectric constant, dielectric loss and dielectric loss tangent were calculated as a function of frequency and explained on the basis of Koop's theory. AC conductivity is found to increase with the frequency but at higher frequencies, ac conductivity start to decreases.

[en] This study has compared the use of standard water quality overlay techniques with that of Getis-Ord Gi* statistical techniques for visualizing the spatial distribution of water quality parameters in an unconfined aquifer beneath the city of Lahore in Pakistan. The non-uniformly distributed groundwater sampling points were uniformly transformed to a grid of evenly distributed values to apply Getis-Ord Gi* statistics. An optimized neighborhood distance value of 700 m was determined for the Getis-Ord Gi* assessment, showing that the aquifer is regionally continuous and there are no barriers to lateral groundwater flow. This statistical approach was initially applied to individual parameters and was found to better define hotspots than that of the conventional method. Similarly, the use of Getis-Ord Gi* values improved the assessment of hotspots of water quality index (WQI) values than conventional overlay techniques.

[en] In this paper, the charge conduction mechanism at high temperature in Al-Gd_2O_3 (MIM) structure has been investigated by performing temperature-dependent current-voltage measurements in the temperature range 280-390 K. MIM structure is realized by electron beam evaporation system where thin films of Gd_2O_3 (40, 60 and 80 nm) and Al metal on both sides of dielectric film were deposited on glass substrate. The possibility of different transport mechanisms has been testified by plotting various graphs. The nonlinear behavior of LnV versus LnI and V"1"/"2 versus LnV/I graphs ruled out the possibility of space-charge-limited conduction (SCLC) and Poole-Frenkel mechanism in Al-Gd_2O_3-Al MIM structure. The straight lines LnI-V"1"/"2 graphs at various temperatures confirmed that Schottky emission is the dominant transport mechanism in Al-Gd_2O_3-Al structure. The calculated values of field barrier lowering coefficient at different measurement temperatures were in good agreement with the theoretical prediction confirming conduction is via Schottky emission. The field-dependent Ln(I/T"2) versus 1000/T plots were obeyed a linear relationship according to Schottky emission theory. Furthermore, the dielectric thickness dependence room-temperature current-voltage characteristics of Al-Gd_2O_3-Al MIM structure were showed strong dependence of current on dielectric film thickness according to Schottky emission theory of conduction current. (orig.)

[en] Nanocomposites based on Polyaniline Titanium dioxide (PANI-TiO₂) were prepared by in situ chemical polymerization. The structure was confirmed by X-rays diffraction studies. The interesting behavior of the XRD pattern around 10% TiO₂ content was marked as critical concentration of the dopant. The crystallite size was found to increase for PANI-TiO₂ nanocomposites. Charge transport mechanism was investigated by temperature dependent dc electrical conductivity measurements in the temperature range of 293 K–353 K. An increase in dc conductivity was found on addition of TiO₂ at all temperatures and three dimensional variable range hopping (3D VRH) model was the most probable model of charge transport. Activation energy, density of states and hopping length were calculated and found to be influenced by TiO₂ incorporation. Structural morphology was studied by scanning electron microscopy (SEM). The granular structure and grain size increased and was confirmed by Transmission Electron Micrographs. The tensile modulus as a function of TiO₂ loading in PANI showed enhancement in mechanical properties. - Highlights: • Template free in situ chemical polymerization. • XRD reveals, 10% critical concentration of the dopant. • Nano size crystal structure by Transmission Electron Microscopy (TEM). • 3D variable range hopping. • Enhancement in mechanical properties.

[en] In this paper, we have grown Cr–Lu₂O₃–Cr structure on glass substrate by electron beam evaporation technique. The electrical characterization of grown MIM diode was performed by temperature dependent current-voltage (I–V) characteristics in between 320–405 K. The electrical measurements revealed that schottky emission conduction mechanism is dominant across the metal-dielectric diode. The further justification in favor of schottky emission was provided by plotting the schottky and Arrhenius plots which show linear behavior. From these graphs we have calculated the temperature dependent dielectric constant whose value is in good agreement with the reported value of lutetium oxide dielectric constant. We have tested the possibility F-N tunneling and Poole-Frankel emission conduction mechanisms and found that these mechanisms are not operative in the diodes under investigation. Activation energy versus V^1/2 graph was also plotted to further justify our argument. (paper)

[en] In this study, we have investigated the charge transport properties of Al-Lu₂O₃-Al metal-insulator-metal (MIM) structure using high temperature, high filed current-voltage (I-V) characteristics. The MIM structure in symetric electrode configuration was fabricated on glass substrate by electron beam evaporation. Various conduction mechanisms have been tested to investigate the dominant charge transport mechanism in underlying MIM structure. Temperature dependent I-V data in the temperature range 323–403 K suggested that at least two different transport mechanisms operated in low and high field regions. The stright line graphs of LnI versus V^1/2 at different values of measurement temperatures confirming the presence of Schottky emission mechanism at low electric fields. The calculated values of dielectric constants at different temperatures found to be close agreement with experimental dielectric constant of Lu₂O₃. The linear relationship between Ln(I/V) versus V^1/2 graph at high electric field region evident that Poole-Frankel (PF) emission is dominant mechanism in high field region. Arrhenius plot, Schottky emission and activation energy graph were also plotted to further probe into the dominant conduction mechanism in Al-Lu₂O₃-Al structure.

[en] In this paper, La³⁺ substituted M-type Ba–Ni hexaferrite nanoparticles having composition Ba_0.8Ni_0.2Fe_12-xLa_xO₁₉ (x = 0, 0.2, 0.4, 0.6, and 0.8) were prepared by co-precipitation route. The phase of the grown NPs was confirmed using X-ray diffraction analysis and results reveal the growth of M-type hexaferrite NPs as a major phase. The energy dispersive X-ray spectroscopy (EDX) was employed to determine the elemental composition of prepared samples. The FTIR spectra of synthesized samples confirm the bond formation of M-type hexaferrites. The optical bandgap was determined by UV-Vis spectroscopy and the results exhibit an increase in optical bandgap with decreasing crystallite size. The vibrating sample magnetometry (VSM) technique was used to analyze the effect of dopant on the magnetic properties like coercivity, saturation magnetization, and remanence of the synthesized samples. The electrical resistivity was measured by two probe method and it was observed that the activation energy shows a decreasing trend with increase in La content. The highly resistive nature of prepared nano ferrites indicates the potential to use these ferrites for high-frequency applications.

[en] A plant mediated, green and cost effective route was utilized for synthesis of pure and Ni-doped Zinc oxide nanoparticles (ZnO-NPs) using Brassica rapa leaf extract. Optical, structural and morphological properties of prepared nanoparticles were affirmed through UV–Vis spectroscopy, X-ray diffraction (XRD) and Scanning electron microscopy (SEM), respectively. The synthesized ZnO-NPs represented hexagonal phase with crystallite size of 27.48 nm and were irregular in shape. The existence of functional groups was explored using Fourier transform infrared spectroscopy. The antibacterial activity of the prepared nanoparticles was verified against a gram positive bacteria Micrococcus luteus and a gram negative bacteria Enterobacter aerogenes which confirmed that ZnO-NPs are efficient antibacterial agents. In addition, the prepared nanoparticles were applied on wheat and pearl millet seeds to investigate their effect on germination. It was observed that there was an appreciable enhancement in seed germination of seeds after treated with the synthesized ZnO-NPs.