Comparative evaluation of extraction of tetra- and hexa-valent neptunium ions by CMPO in a room temperature ionic liquid

ABSTRACT

Solvent extraction studies were performed to understand the extraction behavior of Np⁴⁺ and NpO₂ ²⁺ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML₂ type species, where M = Np⁴⁺ or NpO₂ ²⁺, and L = CMPO. Studies were also carried out with Pu⁴⁺ and UO₂ ²⁺ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species.     

Analysis of DC and AC properties of a humidity sensor based on polyaniline–chromium oxide composites

Polyaniline–Chromia (PANI–Cr₂O₃) composites were synthesized by in situ polymerization. The prepared composites were characterized by scanning electron microscopy, X-ray diffraction and Fourier transforms infrared spectroscopy. The structural studies confirm the polymerization of aniline over Cr₂O₃ particles which results into strong interaction between PANI and Cr₂O₃ particles. Direct current conductivity of composites increases with increase in temperature. Among all composites, 30 wt% shows high conductivity. The humidity sensing mechanism of the PANI–Cr₂O₃ composites is studied and change in its resistance with respect to percentage relative humidity ranging from 20 to 95 % is recorded. The humidity sensing studies shows that the change in the resistance is due to the uncurling of polymer chains by the absorption of water vapor which leads to increase in conduction paths. The results indicate better humidity sensing response by the addition of Cr₂O₃ particles to PANI, among all the composites, 30 wt% composite shows higher sensitivity.     

New benzoxazines from renewable resources for green composite applications

Fully bio‐based composites composed of polybenzoxazine resins obtained from renewable natural resources (such as cardanol, furfurylamine, and stearylamine) and bio‐fiber such as jute fiber were prepared. The purity of the isolated cardanol was determined by Gas Chromatography. The structure of cardanol and its benzoxazine monomers were characterized by FT‐IR, ¹H‐NMR, ¹³C‐NMR, and Mass spectroscopic analysis and its polymerization process was monitored by Differential scanning calorimetry analysis. The composites' tensile and flexural strengths were measured by UTM and its impact strength was measured by IZOD impact tester respectively. The bio composite (PCF‐Bzo/Jute fiber) shows superior thermal and mechanical (from thermogravimetric analysis and dynamic mechanical analysis) properties when compared with stearylamine‐based composite (PCS‐Bzo/Jute fiber). The surface morphologies of the fractured composites were analyzed by Scanning Electron Microscopy. POLYM. COMPOS., 37:573–582, 2016. © 2014 Society of Plastics Engineers     

Prevalence and antimicrobial resistance of Salmonella recovered from processed poultry

This study was conducted to determine the prevalence and antimicrobial resistance of Salmonella isolates recovered from processed poultry. Four hundred eighty pre- and postchill whole broiler chicken carcasses were collected from a poultry processing plant between July 2004 and June 2005. Water samples also were collected at the entrance and exit of the chiller. After preenrichment, carcass and water samples were analyzed for the presence of Salmonella using the automated BAX system followed by traditional culture methods. The proportions of pre- and postchill carcasses that were positive for Salmonella were 88.4 and 84.1%, respectively. Ninety-two percent of water samples collected at the entrance of the chiller were positive for Salmonella, but all exit samples were negative. There was no significant difference in the prevalence of Salmonella between pre- and postchill carcasses (P > 0.05). Salmonella isolates recovered were serotyped and tested for susceptibility to antimicrobials. Thirteen serotypes were identified; the most common were Salmonella Kentucky (59.5%) and Salmonella Typhimurium (17.8%). Three hundred thirty-nine (79.8%) of the isolates were resistant to at least one antimicrobial, and 53.4% were resistant to three or more antimicrobials. Resistance was most often observed to tetracycline (73.4% of isolates), ampicillin (52.9%), amoxicillin-clavulanic acid (52%), ceftiofur (51.7%), streptomycin (35.2%), and sulfisoxazole (21.8%). These results indicate the high prevalence of Salmonella contamination in whole broiler carcasses, and a large number of these Salmonella isolates were resistant to commonly used antimicrobials.     

Pollen morphology and its taxonomic potential in some selected taxa of Caesalpiniaceae observed under light microscopy and scanning electron microscopy

Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification of plants. Therefore, keeping in view the significance of pollen traits, selected taxa of the subfamily Caesalpiniaceae was collected from different geographical regions of Pakistan. The species were then analyzed under both light microscopy and scanning electron microscopy techniques to investigate the importance of micromorphological characters of pollen in the identification and classification of species. Great variation was recorded in equatorial shape, surface ornamentation, tectum, polar diameter, equatorial diameter, and exine thickness. However, little variation was observed in pollen type, polar shape, and fertility of pollen. The equatorial shape of five types was observed: prolate, prolate-spheroidal, spheroidal-subprolate, subspheroidal-prolate, and subspheroidal. Four types of surface ornamentation, psilate, granulate, clavate, and perforate, were recorded. Tectum of five types, intactate, reticulate regulate, medium reticulate, tactate, and striate, was observed. Sexine was thicker than nexine in all studied species. The largest polar diameter was observed in Caesalpinia pulcherrima 64.1 μm while the smallest in Parkinsonia aculeata 26.1 μm. The largest equatorial diameter was found in C. pulcherrima of 70.25 μm whereas the smallest in P. aculeata 27.57 μm. All the pollens analyzed were tricolporate. All studied species have a fertility ratio of more than 90%. A taxonomic key was developed to show the variation in pollen features and delimit species for the correct identification. In conclusion, the pollen traits were found useful to define species boundaries at various taxonomic ranks and will strengthen the taxonomy of this subfamily. Besides, this study also explored the palynological traits and their implication in the taxonomy of the subfamily Caesalpiniaceae.     

Structural and ferroelectric properties of lanthanum modified BPZT ceramics

Lanthanum modified Ba_0.80Pb_0.20Ti_0.90Zr_0.10O₃ (BPZT) ceramics with composition Ba_0.80−xLa_x Pb_0.20Ti_0.90Zr_0.10O₃; x = 0–0.01 in steps of 0.0025 were prepared by conventional solid state method. All the samples were sintered at 1325 °C after compacting in circular discs. Detailed structural and ferroelectric properties were carried out for sintered specimens. X-ray diffraction analysis for all the sintered specimens shows tetragonal structure with perovskite. Coercive field (E_c) and remanent polarization (P_r) to spontaneous polarization (P_s) ratio (P_r/P_s) was found to decrease with increase in temperature. P_r/P_s ratio was found to decrease with increase in x, except x = 0.0025.     

Generalized Filter Topology Using Grounded Components and Single Novel Active Element

This paper introduces a new active element combining the useful features of differential voltage, dual-X and first generation current conveyors. The new proposed active element is further utilized to introduce a new generalized filter topology employing grounded components only. The proposed single active element-based topology benefits from first-order and second-order filter realization by appropriate impedance specialization. The circuit topology with single current input provides two output currents and voltages in each case. A thorough study of proposed active element along with extensive simulations is carried out to validate the filter topology. A detailed non-ideal study is also given. To further support the usefulness of filter topology, higher-order filters are also realized. The new active element and the new filter structure provide advancement to the existing knowledge; with the scope of active element being further exploited for analog signal processing applications in general. The proposed differential voltage dual-X first generation current conveyor (DV-DXCCI) and its filtering applications are simulated using TSMC 0.25  \(\upmu \) m technology.     

Thermal dispersion effect on MHD flow of dusty gas and dust particles through hexagonal channel

In the field of dynamics for a dusty fluid, the volume of the dust particles and flow behaviour of particles in different conditions is very important in engineering problems such as atmospheric fallout, nuclear reactor, powder technology, performance of solid fuel rocket nozzles, air craft icing and so many others. An analysis is presented in this paper to study the effects of thermal dispersion and Viscous dissipation on unsteady flow of a viscous incompressible dusty gas through a hexagonal channel of uniform cross section under the influence of magnetic field and time dependent pressure gradient. The results show the change in velocity profile of gas and particles in the presence of magnetic field with time, thermal dispersion and volume fraction φ.     

SITO High Output Impedance Transadmittance Filter Using FTFNs

FTFN based single input and three outputs transadmittance filter topology supporting simultaneously three filtering signals LP, BP, and HP without any passive component matching conditions is presented. The filter uses three PFTFNs and five passive components and realizes all current signals at high impedances, lending feature of cascadibility to the circuit. The circuit enjoys low sensitivity figures. PSPICE simulation results confirming the theoretical calculations are included.