Hafiz Muhammad Rafique

4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1): X-ray structure and DFT calculations

The title compound, 4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide-oxalohydrazide (1:1), is determined using X-ray diffraction techniques and the molecular structure is also optimized at the B3LYP/6-31G(d,p) level using density functional theory (DFT). The asymmetric unit consists of four independent molecules. The oxalohydrazide molecules have the centre of symmetry at the mid-point of the central C-C bond. Each thiazine ring adopts a half-chair conformation. Intermolecular C-H...O, N-H...O and N-H...N hydrogen bonds produce R22 (10), R22 (13), R33 (12) and R33 (15) rings, which lead to one-dimensional polymeric chains. An extensive three-dimensional supramolecular network of N-H...N, N-H...O, C-H...O and O-H...O hydrogen bonds is responsible for crystal structure stabilization.

Multiferroicity in sol–gel synthesized Sr/Mn co-doped BiFeO3 nanoparticles

A simple and cost effective sol–gel auto-combustion technique was used to synthesize Bi0.9Sr0.1Fe1−xMnxO3 (x = 0, 0.05, 0.10, 0.15 and 0.20) multiferroics. Rietveld’s refined X-ray diffraction patterns validated the synthesis of pure phase bismuth ferrite nanoparticles adopting a rhombohedrally distorted ABO3 type perovskite structure with space group R3c. Morphology of the prepared samples manifested the improved crystallinity with increasing Mn contents in BiFeO3. Uniformly distributed multi-shaped grains having varying sizes were formed after combustion which would affect the microstructural related properties of the parent compound. Energy dispersive X-ray spectroscopy confirmed the presence of the relevant elements in the prepared compositions according to their stoichiometric ratio. Enhanced saturation magnetization was observed with increasing doping concentration in the parent compound. Improved polarization versus electric field loops were observed in Mn and Sr co-doped BiFeO3 nanoparticles. All the properties in the present research work have been explained on the basis of dopants and their concentrations, phase purity, microstructure and grain sizes.

First-principles study of electronic, optical and thermoelectric properties in cubic perovskite materials AgMO3 (M = V,Nb,Ta)

In this paper, first-principles calculations of structural, electronic, optical and thermoelectric properties of AgMO3 (M = V, Nb and Ta) have been carried out using full potential linearized augmented plane wave plus local orbitals method (FP - LAPW + lo) and BoltzTraP code within the framework of density functional theory (DFT). The calculated structural parameters are found to agree well with the experimental data, while the electronic band structure indicates that AgNbO3 and AgTaO3 are semiconductors with indirect bandgaps of 1.60 eV and 1.64 eV, respectively, between the occupied O 2p and unoccupied d states of Nb and Ta. On the other hand, AgVO3 is found metallic due to the overlapping behavior of states across the Fermi level. Furthermore, optical properties, such as dielectric function, absorption coefficient, optical reflectivity, refractive index and extinction coefficient of AgNbO3 and AgTaO3, are calculated for incident photon energy up to 50 eV. Finally, we calculate thermo power for AgNbO3 and AgTaO3 at fixed doping 1019 cm-3. Electron doped thermo power of AgNbO3 shows significant increase over AgTaO3 with temperature.

Ablation, thermal stability/transport and mechanical investigations of modified nanokaolinite impregnated acrylonitrile butadiene rubber composites

Modified nanokaolinite was uniformly dispersed in acrylonitrile butadiene rubber using dispersion kneader and two roller mixing mill. In order to evaluate ablation characteristics of the fabricated composites, high-temperature ablation testing was carried out. The peak incorporation of nanoclay in the rubber matrix has enhanced the ablation resistance up to 97% and reduced the temperature elevation at the back face of the nanocomposite up to 51% during the 200s oxy–acetylene flame exposure on the surface of the ablator. Thermogravimetric and differential thermal analyses elucidate the thermal endurance improvement with increasing filler contents in the polymer matrix. Thermal conductivity and thermal impedance of the composite specimens were evaluated on the domestically manufactured thermal conductivity measuring apparatus. It is scrutinized that the former property reduced up to 49% at and the subsequent characteristic of the rubber composite is elevated up to 43% at 373 K with the 30 wt% incorporation of the nanoclay into the base rubber composition. Mechanical properties of the acrylonitrile butadiene rubber composite specimens were significantly enhanced with increasing filler introduction into the host matrix. Porous char morphology, polymer pyrolysis and composition of the ablated samples were analyzed using scanning electron microscopy and energy dispersive spectroscopy analyses.

Appraisal of drinking water quality of tehsil Jampur, Pakistan

AbstractThe quality of drinking water is vital for humans in order to remain alive, healthy and disease free. Consequently, it is indispensible to make sure that the available drinking water is uncontaminated. This study aimed at finding the quality of drinking water in Jampur, which is one of the tehsils of district Rajanpur in South Punjab, Pakistan. Thirty water samples were collected from different locations of the study area. These samples were gathered from different sources such as hand pump, injector pump, tube well and water supply line. The water quality was examined by comparing its standards with World Health Organization provided guidelines. It was found that majority of the Jampur’s population were using contaminated water, which is very harmful and alarming. This contaminated water could cause a potential risk to people’s health through many waterborne and skin diseases. The contamination of water could be due to dissolved contaminants and excessive ions such as arsenic, sodium, calcium or ...

Enhanced ferromagnetic characteristics in Mn-doped ZnO: A promising diluted magnetic semiconductor

Zn1−xMnxO (x = 0, 0.02, 0.04, 0.06, 0.08 and 0.1) nanocrystalline diluted magnetic semiconductors (DMSs) were synthesized using sol–gel-based auto-combustion technique. X-ray diffraction (XRD) analysis of all the synthesized samples indicated pure wurtzite hexagonal structure without any secondary phase with perfect solubility of Mn contents in ZnO matrix. The increase in Mn concentration reduced the average crystallite size as evaluated by the Scherrer’s formula. Morphological analysis performed using a field emission scanning electron microscope (FESEM) indicated nearly an ordered surface morphology with some porosity and few cracks. Energy dispersive X-ray (EDX) spectroscopy confirmed the stoichiometric contents of Zn, Mn and O in each sample. Micrographs of all the samples exhibited a decrease in grain size with increase of Mn contents. Magnetic measurements performed using vibrating sample magnetometer (VSM) confirmed room temperature ferromagnetism exhibiting an increase in saturation magnetization and coercivity with increasing Mn contents in all the prepared samples.

Assessment of drinking water quality of Tehsil Alipur, Pakistan

AbstractPoor quality of drinking water is one of the major threats to human health. Several potential sources such as toxic chemicals, minerals, effluent outfalls from industrial facilities, waste treatment plants, and run-off from agricultural land can contaminate drinking water. To ensure the accessibility of uncontaminated and safe drinking water, its quality should be managed and monitored carefully on a regular basis. A research study was conducted to evaluate the quality of drinking water in tehsil Alipur of district Muzaffargarh, Pakistan. Water samples were collected from different sources such as tube well, hand pump, injector pump, and water supply line from 27 different locations during 2007. The samples were examined for physical, chemical, and bacteriological contamination. Five physical parameters (pH, turbidity, hardness, total dissolved solids, and conductivity) and chemical parameters including sodium, calcium, magnesium, potassium, chloride, nitrate, sulfate, and bicarbonate were tested ...

2-Chloro-4-(2-iodo­benzene­sulfonamido)­benzoic acid

In the title compound, C13H9ClINO4S, the dihedral angle between the aromatic rings is 81.04 (17)°. The disposition of the I and Cl atoms attached to the two rings is anti. In the crystal, molecules are connected via O—H⋯O and N—H⋯O hydrogen bonds.

Structural, Morphological, and Magnetic Characterization of Sol-Gel Synthesized MnCuZn Ferrites

Manganese copper ferrites belong to a family of ferrites with specific importance due to their high permeability values and low losses at low frequencies. In this paper, a series of ferrite samples has been synthesized using a novel and low cost sol-gel autocombustion route in order to systematically investigate the structural, compositional, morphological, and magnetic properties when zinc is substituted by copper in the series. X-ray diffraction reveals that all the samples have characteristic cubic spinel structure. The effect of zinc substitution at the copper site on the chemical bonding of the ferrite samples was investigated by Fourier transform infrared spectroscopy. Energy dispersive X-ray analysis was performed to determine the homogeneity and stoichiometric composition of elements present in the samples. Nanosized, uniformly shaped grains were evident from the images obtained using a scanning electron microscopy, which indirectly confirms the significance of the autocombustion synthesis technique employed in this paper. Magnetic properties determined using a vibrating sample magnetometer exhibited that zinc substitution could enhance the saturation magnetization of the samples, attributed to the substitution of a paramagnetic element (zinc) by a diamagnetic one (copper).

Geostatistical cokriging and multivariate statistical methods to evaluate groundwater salinization in Faisalabad, Pakistan

In the present study, multivariate techniques and geostatistical cokriging were used to look into the groundwater salinization of district Faisalabad. The groundwater condition of district Faisalabad has become miserable because of the rapid increase in population, industrial wastes, and agrochemical application. As a result, majority of the people do not have access to pure drinking water and, consequently, polluted water is causing many deaths per year. A number of 220 water samples based on instructions of World Health Organization (WHO) were taken from four main sources such as hand pump, injector pump, tube well, and water supply. All samples were tested for 12 water quality parameters and summary statistics were calculated to compare the water quality parameters with WHO permissible limits. Initially, correlation matrix was constructed to evaluate the most significant parameters and later on used principal component analysis (PCA) to select those parameters causing maximum variation. Dendrogram based on cluster analysis conveyed same sort of information as delivered by PCA. First, factor of PCA contributed 41.6% of total variation. Six water quality parameters such as sulfate, calcium, total dissolved solids, sodium, chloride, and magnesium were found to be most alarming because all of these have factor loadings greater than 75%. Cross-variogram based on cokriging showed spatial dependence as well as positive pairwise spatial correlation among all parameters. The prediction maps highlighted the most dangerous and health hazard areas; therefore, may be very helpful for water management agencies to target those high-risk areas. It was found that the area with east latitude 31.0°–31.4° and north longitude 72.8°–73.2° is most alarming zone.