Measurements of Particulate (PM2.5), BC and Trace Gases Over the Northwestern Himalayan Region of India

Ambient trace gases (NH₃, NO, NO₂ and SO₂) and black carbon (BC) were measured along with particulate matter (PM_2.5) over the northwestern Himalayan region (Palampur, Kullu, Shimla, Solan and Nahan) of Himachal Pradesh (HP), India in a campaign mode during 12–22 March 2013 to evaluate the ambient air quality of the region. The average mixing ratio of ambient NH₃, NO, NO₂ and SO₂ were recorded as 7.1 ± 2.6, 3.1 ± 1.3, 3.9 ± 1.4 and 1.7 ± 0.7 ppb respectively over the northwestern Himalayan region. The average concentration of BC was estimated as 2.2 ± 0.5 µg m^?3 over the region whereas average concentration of PM_2.5 mass was estimated as 41.8 ± 7.9 µg m^?3. The spatial variation of ambient trace gases (NH₃, NO, NO₂ and SO₂), BC and PM_2.5 over the northwestern Himalayan region, India reveals that the region is mainly influenced by local activities, i.e., tourism activities, agricultural activities, biomass burning and vehicular emission. A significant positive linear correlation of NH₃ and NH₄ ⁺ with SO₄ ^2?, NO₃ ^? and Cl^? (NH₄ ⁺ vs. SO₄ ^2? , r ² = 0.652; NH₄ ⁺ vs. NO₃ ^?, r ² = 0.701; and NH₄ ⁺ vs. Cl^?, r ² = 0.627) of the PM_2.5 indicates the possible formation of (NH₄)₂SO₄, NH₄NO₃ and NH₄Cl aerosols over the region.     

Vertical Profile of Particulate Matter Concentrations in Indoor Air (Case Study: Karaj,Iran)

Particulate matter is one of the most significant pollutants in indoor environments. The study of vertical profile concentration coefficients of different particulates leads us to figure out the most accurate pattern of vertical profile change of these hazardous particles. In this case, three different sizes of particulate vertical profile patterns, PM_1.0, PM_2.5, and PM₁₀, were evaluated in indoors in the city of Karaj. Samplings of first and fourth floors of 5 buildings located in different areas of Karaj were conducted constantly during 2011. The results of Mahestan Station illustrate the highest average concentration of PM₁₀ (173 µg/m³) whereas the RajaieShahr Station measurements indicates the highest average concentrations of PM_2.5(66 µg/m³) and also PM_1.0(51 µg/m³). Generally, the concentrations of the particulates in the first floors were higher than that in the fourth floors, and according to the air evaluation stations, all the particulates including PM_1.0, PM_2.5, and PM₁₀ had concentrations higher than the annual standard.     

A Non-destructive FTIR Method for the Determination of Ammonium and Sulfate in Urban PM<Subscript>2.5</Subscript> Samples

Traditionally, the atmospheric particle composition is analyzed using destructive methods. In general, the destructive methods lead to the destruction of the samples, higher cost of the analysis and larger analysis time. In view of aforesaid, in current work, we present a method for the non-destructive analysis of atmospheric particles using open path-Fourier transform infrared spectroscopy (OP-FTIR). The developed method has been used for the measurement of ammonium and sulfate in atmospheric particles without destroying the samples. Here, we targeted the said species because of their relative importance for air pollution episode formation. Particulate sulfate plays a major role in formation of haze. However; particulate acidity is an important factor in this process, which is governed by particulate ammonium concentration. Therefore, both SO₄^2? and NH₄⁺ are important as far as atmospheric chemistry of haze formation is concerned. In the present study, the qualitative and quantitative estimation of ammonium and sulfate ions in PM_2.5 (particulate matter with aerodynamic diameter less than 2.5 µm) was carried out using OP-FTIR with the developed method. The seasonal average concentration of NH₄⁺ and SO₄^2? were measured to be 12.00 ± 5.80, 31.71 ± 12.71 µg/m³ respectively for winters, 3.00 ± 0.85 and 8.00 ± 2.28 µg/m³ respectively for summers and 2.60 ± 1.90 and 7.00 ± 5.21 µg/m³ respectively for monsoon season. The observed results are found to be in good agreement with that of other studies using destructive methods.     

Effect of firing temperature on microstructure and dielectric properties of chromium oxide based glass composite thick films on stainless steel substrate

We report the influence of firing temperature on Al₂O₃–chromium oxide based (Cr₂O₃–Bi₂O₃–B₂O₃–SiO₂–Al₂O₃) glass composite (named as GC-1 composite) thick films of thickness (27?±?3) µm deposited onto 0.6 mm thick austenitic grade stainless steel (DIN 1.4301/AISI 304) substrate by screen printing technique, which can be used as a substitute to alumina substrate. Prior to formulation of glass composite, the chromium oxide based glass (named as GC-1) phase was prepared separately by melt-quench technique. X-ray diffraction analysis confirmed amorphous nature of the GC-1 glass. The thermo gravimetric analysis and differential scanning calorimetry of the GC-1 glass shows thermal stability over the temperature range of 20–1000 °C. We observed that the firing temperature significantly influences microstructural and dielectric properties of the GC-1 composite film. The deposited GC-1 composite films onto stainless steel base were fired at temperatures between the range of 550–750 °C, showed the surface resistivity in the range of (1.0–6.9?±?0.2) × 10¹² ohms per square. The microstructure of these composite films recorded using scanning electron microscopy and electrical properties recorded using LCR meter were correlated with each other. The study revealed that the film fired at 600 °C were found to be superior among the samples under investigation in terms of microstructure, stable relative permittivity [36 (±?1)] and low loss tangent [0.02 (±?0.002)] in frequency range of 1–200 kHz, and surface resistivity (~?5.1?×?10¹² ohms per square).     

Mineralogical Studies of Coal Fly Ash for Soil Application in Agriculture

Coal fly ash procured from Guru Gobind Singh Super Thermal Power Plant, Ropar, Punjab, India, was analyzed for its mineralogical content and thermal stability by x-ray diffraction (XRD), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and physicochemical properties. XRD studies showed that major crystalline phases observed were quartz (SiO₂) and aluminum silicon oxide (Al_4.52Si₁.₄₈) with macro- and microelement (N, P, K, Mg, Zn, S, and Fe). Fly ash showed thermal stability up to 500°C and reduction in weight was up to 200°C, primarily due to loss of water and decarboxylation as revealed by TGA plots. FTIR of fly ash showed that the most prominent peaks in the spectra corresponded to Si–O and Al–O stretch vibrations. Coarse-grain accumulation of fly ash indicated the presence of 70% of fine-grained particles of 0.075 mm. Coal fly ash was alkaline in nature (pH 7.85 ± 0.03) with an electrical conductivity of 0.14 ± 0.02 µS m^?1, water holding capacity of 62%, low bulk density of 0.99 g cm^?3, and a surface area of 0.96 m² g^?1. With properties similar to that of soil coal, fly ash represents a suitable material for use in specific quantities as a soil amending agent in agriculture.     

Cleanable Air Filter Transferring Moisture and Effectively Capturing PM2.5

The lethal danger of particulate matter (PM) pollution on health leads to the development of challenging individual protection materials that should ideally exhibit a high PM_2.5 purification efficiency, low air resistance, an important moisture‐vapor transmission rate (MVTR), and an easy‐to‐clean property. Herein, a cleanable air filter able to rapidly transfer moisture and efficiently capture PM_2.5 is designed by electrospinning superhydrophilic polyacrylonitrile/silicon‐dioxide fibers as the adsorption–desorption vector for moisture‐vapor, and hydrophobic polyvinylidene fluoride fibers as the repellent components to avoid the formation of capillary water under high humidity. The desorption rate of water molecules increases from 10 to 18 mg min^?1, while the diameters of polyacrylonitrile fibers reduce from 1.02 to 0.14 µm. Significantly, by introducing the hydroxyl on the surface of polyacrylonitrile nanofibers, rapid adsorption–desorption of the water molecules is observed. Moreover, by constructing a hydrophobic to super‐hydrophilic gradient structure, the MVTR increases from 10 346 to 14 066 g m^?2 d^?1. Interestingly, the prepared fibrous membranes is easy to clean. More importantly, benefiting from enhanced slip effect, the resultant fibrous membranes presented a low air resistance of 86 Pa. A field test in Shanghai shows that the air filter maintains stable PM_2.5 purification efficiency of 99.99% at high MVTR during haze event.     

Formulated quasi-solid state electrolyte based on polypyrrole/polyaniline–polyurethane nanocomposite for dye-sensitized solar cell

A polymer-based quasi-solid state electrolyte using polyurethane (PU) matrix was applied for dye-sensitized solar cell (DSSC). To further improve the performance of the electrolyte, 10 wt% of conductive polymer [polypyrrole (PPy) and polyaniline (PANi)] nanoparticles were introduced into the matrix. The samples were named PU-10%PPy and PU-10%PANi, and characterized using ATR–FTIR, TEM, DLS, a transmitted light microscope, a reflected light microscope, and TGA. The formulated polymeric nanocomposites were immersed in the liquid electrolyte and the polymer matrix absorbency, conductivity (σ), ion diffusion coefficient (D_ff), and photovoltaic performance in the DSSC were measured. Polymer matrix absorbency and D_ff of PU-10%PPy (1.72 g g^?1, 1.52 µcm² s^?1) and PU-10%PANi (1.74 g g^?1, 1.31 µcm² s^?1) were lower than the PU matrix (2.01 g g^?1, 1.68 µcm² s^?1). However, the conductivity of PU-10%PPy and PU-10%PANi was higher than the PU matrix (2.64, 2.69, and 2.59 mS cm^?1, respectively). The efficiency of the DSSC based on PU-10%PANi was the highest, with open circuit voltage of 709 mV, short circuit current of 3.67 mA cm^?2, fill factor of 0.62, and light-to-energy conversion efficiency of 2.68%.     

The influence of the structure and the composition of water/AOT-Tween 85/IPM microemulsion system on transdermal delivery of 5-fluorouracil

The purpose of this study was to investigate the influence of the structure and the composition of water/Aerosol-OT (AOT)-Tween 85/isopropylmyristate (IPM) microemulsion system (WATI) on transdermal delivery of 5-fluorouracil (5-FU). The structure of WATI was characterized by measuring surface tension, density, viscosity, electric conductivity, and differential scanning calorimetry. The effect of the drug loading, water content, component compositions and the amount of mixed surfactant on permeation of 5-FU through mice skin was evaluated by using Franz-type diffusion cells. The results in vitro implied that WATI was W/O microemulsion when the water content was below 20 wt% at fixed 20 wt% of mixed surfactant at 25°C, then might be transformed to a bicontinuous structure, finally, formed O/W microemulsion with water content over 30 wt%. Increase of the drug loading can directly facilitate the penetration of the drug across the skin. Drug diffusion after 12?h from the bicontinuous microemulsion (795.1?±?22.3 µg·cm^?2) would be fastest compared to that from the W/O microemulsion (650.2?±?11.7 µg·cm^?2) and the O/W microemulsion (676.6?±?14.8 µg·cm^?2). The combination of AOT and IPM could bring about synergistic effect on the skin enhancement, however, Tween 85 in WATI decreased the cumulative permeation amount of 5-FU. The content of mixed surfactant had no effect on the permeation of 5-FU at fixed surfactant/cosurfactant ratio (K_m?=?2). Thus, the increased transdermal delivery the hydrophilic drug of 5-FU was found to be concerned with both of the structure and the composition of WATI.     

Biofiltration of H<Subscript>2</Subscript>S-rich biogas using <Emphasis Type="Italic">Acidithiobacillus thiooxidans</Emphasis>

Biogas has limited use in energy generation mainly due to the presence of hydrogen sulfide (H₂S). Currently, most of the techniques employed in the removal of H₂S from biogas have a chemical base, with high material costs and generating secondary pollutants. Biological processes for H₂S removal have become effective and economical alternative techniques to traditional gas-treatment systems based on physicochemical techniques. Therefore, the aim of this work was to investigate the performance of a bench-scale biofilter for the removal of H₂S present in synthetic biogas. In addition, CO₂ and CH₄ concentrations in the outlet biogas were evaluated. The inoculum used in the experiment was composed of Acidithiobacillus thiooxidans fixed on a packing of wood chips. Synthetic biogas was supplied to the system with a composition of 60 % CH₄, 39 % CO₂ and 1 % H₂S. The biofilter operated continuously for 37 days with an average H₂S removal efficiency of 75 ± 13 % and maximum of 97 %. The elimination capacity of the system reached an average of 130 ± 23 g m^?3 h^?1 and a maximum of 169 g m³ h^?1. The biofiltration system showed an average reduction of only 6 % in CH₄ concentration from biogas. Thus, besides being efficient in the removal of H₂S, the system was able to maintain the biogas energy value.     

Status of PM in Seoul metropolitan subway cabins and effectiveness of subway cabin air purifier (SCAP)

The increasing importance of indoor air quality management on public transport led the Korean government to amend the indoor air quality control in public use facilities, etc. Act including modes of public transport under the Act from June 2013. Particulate matter (PM) in subway systems is reported as being mostly generated by friction—between the wheels and the rails, between the wheels and the brake pads, and between the catenaries and the pantographs. In order to reduce PM level in subway cabins, a newly developed subway cabin air purifier (SCAP) was installed on the ceilings of the cabins. In this study, we analyzed indoor PM concentrations through continuous measurement of PMs less than 10 μm in diameter (PM₁₀) and PMs less than 2.5 μm in diameter (PM_2.5) in the cabins of line 2 and line 5 of the Seoul metropolitan subway network, comparing the concentrations in cabins where SCAP devices were installed to cabins without them in order to verify SCAP effectiveness. In both cabins with and without SCAP, the ratio of indoor to outdoor PM₁₀ (I/O for PM₁₀) showed a two-times higher value in line 5 than in line 2, which indicated that the entirely underground line 5 was less ventilated with outdoor air. In addition, the ratio of indoor PM_2.5/PM₁₀ showed that coarse mode PM was more abundant in line 5 due to poor ventilation in the tunnel sections compared to that of line 2. Regarding the effectiveness of SCAP, it was found that changes of PM₁₀ concentrations in line 2 and line 5 were from 132.8 to 112.2 μg/m³ (15.5 % efficiency) and from 154.4 to 114.2 μg/m³ (26.0 % efficiency) after SCAP installation, respectively.     

Density of Vapor and Liquid Pentafluorobenzene Along the Saturation Line

The density of vapor and liquid pentafluorobenzene along the liquid–vapor coexistence curve has been studied by a gamma-ray attenuation technique over the temperature range from 293.5K to 530.9K. According to measurements, the coordinates of the critical point are T _C = (531.04 ± 0.05) K and ρ _C = (518.8 ± 2) kg · m^?3. The critical exponent β of the coexistence curve equals 0.345 ± 0.005. The results of our measurements were compared with data available in the literature. The height dependence of the density of a two-phase sample was investigated in relation to the temperature and time. These experiments made it possible to determine the isothermal compressibility of liquid and vapor phases near the critical point.     

Quantitative determination of raw and functionalized carbon nanotubes for the antibacterial studies

The UV–visible spectrophotometric method has been described the study of raw carbon nanotubes (R-MWCNTs) and functionalized multiwall carbon nanotubes (F-MWCNTs) for the control of bacterial growth by using validated analytical techniques. The absorption spectra of functionalized carbon nanotubes (F-MWCNTs) and raw carbon nanotubes (R-MWCNTs) show maximum absorbance at λ _max 600 nm. The linear relationship was found between absorbance and concentration of R-MWCNTs and F-MWCNTs in the range of 0.25–2.0 μg mL^?1. The linear regression equation was evaluated by statistical treatment of calibration data and gives the value of correlation coefficient for F-MWCNTs (0.9999) and R-MWCNTs (0.9993), which indicate excellent linearity. The Optical and regression characteristics of the proposed method were found apparent molar absorptivity, limits of detection (LOD), and limit of quantitation (LOQ) for R-MWCNTs and F-MWCNTs (5.75 × 10²: 8.25 × 10² L mol^?1 cm^?1), (0.052: 0.018 μg mL^?1), and (0.055: 0.158 μg mL^?1), respectively. The validity of the proposed method was checked by precision, accuracy, linearity, limits of detection (LOD), and limit of quantitation (LOQ). The RSD (%) and quantitative recoveries (%) were obtained (0.026–0.0086) and (100.34 and 100.71) for R-MWCNTs: for F-MWCNTs by UV–visible spectrophotometric, respectively.     

Determination of tangential momentum accommodation coefficient and slip coefficients for rarefied gas flow in a microchannel

This paper presents an experimental study of rarefied gas flow in a trapezoidal microchannel with a constant depth of 103 µm, top width of 1143 µm, bottom width of 998 µm and length of 2 cm. The aim of the study is to verify the upper limit of the validity of the second-order slip boundary condition to model rarefied gas flows. The slip coefficients and the tangential momentum accommodation coefficient (TMAC) are determined for three different gases, viz. argon, nitrogen and oxygen, and it is observed that they compare well to the literature values. The range of mean Knudsen number (Kn_m) investigated is 0.007–1.2. The non-dimensional mass flow rate exhibits the well-known Knudsen minimum in the transition regime (Kn_m?~?1). It is seen that the Navier–Stokes equation with a second-order boundary condition fits the data satisfactorily with a high value of correlation coefficient (r²?>?99.95%) in the entire range of Kn_m investigated. This work contributes by extending the range of Knudsen number studied in the context of validity of the second-order slip boundary condition.     

Doping mechanisms and electrical properties of bismuth tantalate fluorites

Phase-pure bismuth tantalate fluorites were successfully prepared via conventional solid-state method at 900 °C in 24–48 h. The subsolidus solution was proposed with the general formula of Bi_3+x Ta_1?x O_7?x (0 ≤ x ≤ 0.184), wherein the formation mechanism involved a one-to-one replacement of Ta⁵⁺ cation by Bi³⁺ cation within ~4.6 mol% difference. These samples crystallised in a cubic symmetry, space group Fm-3 m with lattice constants, a = b = c in the range 5.4477(± 0.0037)–5.4580(± 0.0039) Å. A slight increment in the unit cell was discernible with increasing Bi₂O₃ content, and this may attribute to the incorporation of relatively larger Bi³⁺ cation in the host structure. The linear correlation between lattice parameter and composition variable showed that the Vegard’s law was obeyed. Both TGA and DTA analyses showed Bi_3+x Ta_1?x O_7?x samples to be thermally stable as neither phase transition nor weight loss was observed within ~28–1000 °C. The AC impedance study of Bi₃TaO₇ samples was performed over the frequency range 5–13 MHz. At intermediate temperatures, ~350–850 °C, Bi_3+x Ta_1?x O_7?x solid solution was a modest oxide ion conductor with conductivity, ~10^?6–10^?3 S cm^?1; the activation energy was in the range 0.98–1.08 eV.     

A Novel Fullerene Hydroxamic Acid for the Liquid–Liquid Extraction,Separation, Preconcentration,and Spectrophotometric and ICP‐AES Determination of Vanadium

Abstract

A new reagent N‐phenyl‐(1,2 methanofullerene C₆₀)61‐formohydroxamic acid (PMFFA) is reported for extraction and trace determination of vanadium(V) in nutritional and biological substrates. The extraction mechanism of vanadium from 6 M HCl media is investigated. The influence of PMFFA, diverse ions, and temperature on the distribution constant of vanadium examined. The over all stability constant (log β₂ K _e ) and extraction constant (K _ex) are 20.89 ± 0.02 and 8.0 ± 0.02 × 10^?15, respectively in chloroform. The thermodynamics parameters are calculated and kinetics of vanadium transport is discussed. The system obeys Beer's law in the range of 3.2–64.0 ng mL^?1 of vanadium(V). The molar absorptivity is 7.96 × 10⁵ L mol^?1 cm^?1, at 510 nm. The PMFFA–vanadium(V) complex chloroform extract in chloroform was directly inserted into plasma for ICP‐AES measurement, which increases the sensitivity by 50 folds and obey Beer's law in the range of 50–1200 pg mL^?1 of vanadium(V). The method is applied for determination vanadium in real standard samples, sea water, and environmental samples.     

Synthesis,physical, ultrasonic waves,mechanical, FTIR,and dielectric characteristics of B2O3/Li2O/ZnO glasses doped with Y3+ ions

Six specimens of glasses with formula (70???x)B₂O₃/15Li₂O/15ZnO/xY₂O₃: x?=?0.0, 0.5, 1.0, 1.5, 2.0, and 2.5 mol%) have been synthesized via a conventional melt quenching technique. The produced specimens were named as BLZY0.0–BLZY2.5 according to x values. The physical, ultrasonic longitudinal (V_L) and shear (V_S) velocities, FTIR, and dielectric (50 Hz to 5 MHz) characteristics of the prepared glasses have been examined. With increasing content of Y₂O₃ from 0.0 to 2.5 mol%, the density (ρ) of the system increases linearly from 2512?±?11 to 2695?±?14 kg/m³, while the molar volume (V_M) decreases linearly from 2.6?±?0.011 to 2.57?±?0.013?×?10^?5 m³/mol. The oxygen packing density (OPD) as a number of the oxygen per unit composition in the glass sample is describing the packing tightness of the oxide network and thoroughly the compactness of the glass matrix. Values of the average boron–boron separation (d_B–B) decrease from 4.162 to 4.035?×?10^?10 (m) with 0 to 2.5 mol% Y₂O₃. Increasing formation of Y³⁺ ionic bonds with [BO_4/2]^1? may have an effect of lowering bond strength of B–O and thus shifting the absorption IR peak position. By increasing Y₂O₃ content in the investigated samples, the (V_L) and (V_S) increase linearly for the full-studied compositional range. The increasing number of strengthened bonds due to change coordination of B ions from 3 to 4 due to the increasing field strength of inserted accumulated Y³⁺ ions has the incentive impact to higher mechanical properties. The dielectric constant was decreased for Y₂O₃ content up to 1.5 mol% referring to cross-linkage formation with other elements, while the reduction in porosity at high content of Y₂O₃ is the main responsible for gradual enhancement in dielectric constant.

     

High surface area ordered mesoporous carbon for high-level removal of rhodamine B

We report the synthesis of ordered mesoporous carbons (OMCs) with high surface area by the variation of mass ratio of tetraethylorthosilicate (TEOS) to resol, followed by carbonization and removal of silica. The obtained OMCs were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N₂ adsorption and desorption analysis, Zeta potential and Fourier transform infrared spectroscopy. Results reveal that the OMCs were transformed from ordered to disordered structure at high mass ratio of TEOS/resol. A typical sample of OMCs possesses very high specific surface area of 1906 m² g^?1 and large pore volume of 1.8 cm³ g^?1. The OMCs as adsorbent show an ultrahigh-level adsorption capacity for the removal of toxic dye Rhodamine B (1028 mg g^?1) in the short contact time (60 min). The adsorption follows pseudo second-order kinetics with rate constant 2.5 × 10^?4 g mg^?1 min^?1, showing rapid adsorption properties. The OMCs can be reused; though the adsorption capacity seems to decrease somewhat after each cycle tested over 10 reuse cycles, it might be affected by the chemisorptions. The adsorption mechanism study reveals that the adsorption proceeds with hydrogen bonding between hydrogen atom of carboxylic group at OMCs and electronegative element (nitrogen) of RhB. It is concluded that the surface area and pore volume of the OMCs is tuned by the variation of mass ratio of TEOS to resol which is also demonstrated to have ultrahigh adsorption capacity for the model RhB dye.     

An Investigation into Pressure Fluctuations and Improved Modeling of Solids Friction for Dense-Phase Pneumatic Conveying of Powders

The aim of this paper is to investigate into flow mechanism with the help of pressure signal fluctuations analysis and modeling solids friction in case of solids–gas flows for fluidized-dense-phase pneumatic conveying of fine powders. Materials conveyed include fly ash (median particle diameter 30 µm; particle density 2300 kg m^?3; loose-poured bulk density 700 kg m^?3) and white powder (median particle diameter 55 µm; particle density 1600 kg m^?3; loose-poured bulk density 620 kg m^?3). These were conveyed in different flow regimes varying from fluidized-dense-to-dilute phase. To obtain information on the nature of flow inside pipeline, static pressure signals were studied using technique of Shannon entropy. Increase in the values of Shannon entropy along the flow direction through the straight-pipe sections were found for both the powders. However, drop occurred in the Shannon entropy values after the flow through bend(s). Change in slope of straight-pipe pneumatic conveying characteristics along the flow direction is another factor which provided indication regarding change in flow mechanisms along the flow. A new technique for modeling solids friction factor has been developed using a solids volumetric concentration and ratio of particle terminal settling velocity to superficial air velocity by replacing the conventional use of solids loading ratio and Froude number, respectively. The new model format has shown promise for predictions under diameter scale-up conditions.     

Preparation, evaluation and bioavailability studies of indomethacin-bees wax microspheres

The present study envisages the preparation of microspheres containing indomethacin (IM) as model drug and bees wax as carrier, and to compare the in vitro release and pharmacokinetics of prepared IM formulation with commercially available oral formulation Microcid^®SR. The microsphere formulations were prepared by meltable emulsified dispersion and cooling induced solidification. Surface morphology of microspheres has been evaluated using scanning electron microscopy (SEM). The SEM images revealed the spherical shape of microspheres and more than 98.0% of the isolated microspheres were in the size range 115–855 μm. Differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy studies indicated that the drug after encapsulation with bees wax was stable and compatible. A single dose randomized complete cross over study of IM (75 mg) microspheres was carried out on 8 healthy Albino sheeps. Plasma IM concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The T _max, C _max, AUC_O-24 and T _1/2 values of Microcid^®SR and optimized formulation were 3.0 h, 2038 ± 51.31 ng/ml, 9528 ± 129.65 ng/ml h^?1, and 2.59 ± 0.02 h^?1; and 3.2 h, 1940 ± 22.61 ng/ml, 8751 ± 41.32 ng/ml h^?1, and 2.68 ± 0.02 h^?1, respectively. Beeswax microspheres showed controlled release and it can be concluded that both the prepared formulation and Microcid^®SR are bioequivalent.     

The fabrication and pyroelectric properties of single crystalline PZT nanorod synthesized by hydrothermal reaction

In this paper, the effect of surfactant polyvinylalcohol (PVA) and polyacrylate acid (PAA) on shape evolution of Pb(Zr_0.3Ti_0.7)O₃ (PZT) nano materials synthesized by hydrothermal method was studied. PZT nanorod array was grown on the conduction substrate surface of (100) Nb–SrTiO₃ with optimized PVA and PAA concentrations. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were used to characterize the PZT nanomaterials. The results demonstrated that the optimization concentration of PVA and PAA were 0.8 and 3.2 g L^?1, respectively. The pyroelectric coefficient of the PZT nanorod array was 1.75 × 10^?9 C cm^?2 K^?1 before poling and 2.56 × 10^?9 C cm^?2 K^?1 after poling. This low temperature synthesized PZT nanorod array shows great potential application in pyroelectric nanodevices.