Removal of lead ions from industrial waste water by different types of natural materials

The adsorption capacity of some natural materials for lead such as animal bone powder, active carbon, Nile rose plant powder, commercial carbon and ceramics was studied. The V/m ratio has been chosen to be 500 ml/g. The adsorption process was affected by various parameters such as contact time, pH and concentration of lead solution. The lead uptake percent reaches equilibrium state after 15, 30, 45 and 120 min for bone powder, active carbon, plant powder and commercial carbon, respectively. The uptake percent of lead increased by increasing pH value. The sequence of lead uptake percent (% adsorption) at constant pH from certain concentration of lead nitrate solution by the different natural materials is in the order: bone powder > active carbon > plant powder > commercial carbon. The uptake percent of lead is increased by decreasing the concentration of lead at constant pH. The capacity of lead adsorbed from nitrate solution by the different natural materials increased by increasing pH value. The synthetic and industrial waste-water samples were treated by using the different natural materials (contact time 3h, pH = 4). The percent removal of lead was 100% by bone powder, 90% by active carbon, 80% by plant powder and 50% by commercial carbon. There was no removal of lead by ceramics. This may be due to the presence of high percent of lead in the constituent of ceramics (372 mg/g).     

Biodegradable microparticulates of beta-estradiol: preparation and in vitro characterization

Beta-estradiol has been recommended for the long-term therapy of osteoporosis and its oral formulations are subjected to intensive first pass metabolism. The present investigation was aimed at preparing and characterizing biodegradable microparticles of beta-estradiol with polymers such as PLA, PLGA 85/15, PLGA 75/25, and their mixtures. The microparticles were prepared by solvent evaporation method using methylene chloride as a solvent and polyvinyl alcohol as a surfactant. The drug-polymer ratios were 1:3, 1:5, and 1:7. The prepared microparticles (twelve formulations) were tested for encapsulation efficiency and in vitro drug release in 50% methyl alcohol/phosphate buffer pH 7.4. The results showed that the encapsulation efficiency varied from 81 to 100% and the formulation fabricated from PLGA 85/15 (1:3) showed less burst and consistent long time release. This formulation when further characterized displayed irregular spherical shape with an average particle size of 72 µm. The crystallinity of the drug was reduced when investigated using X-ray diffractometry. No chemical interaction between the drug and the polymer was observed as evidenced by FT-IR analysis. The results indicated that beta-estradiol biodegradable microparticles with PLGA 85/15 (1:3) could be a suitable approach for long term therapy of osteoporosis.     

A Wide-Band Satellite Microwave Switch Matrix for SS/TDMA Communications

A lightweight, broad-band, 8 × 8 crossbar microwave switch matrix (MSM) has been developed for satellite-switched timedivision multiple-access (SS/TDMA) operation anywhere in the 6 GHz up-link and/or 4 GHz down-link bands. The nearly transparent performance characteristics in the 3.5-6.5 GHz band, for any of the highly flexible interconnect possibilities, have been facilitated by the design of a low-power-consuming resistively matched PIN diode switch. Broad-band push-pull connectors are used to simplify assembly and disassembly of this modular three-dimensional matrix. The switch control electronics (SCE) circuits have been implemented as custom-designed LSI chips for integration within the MSM input distribution networks. Design considerations and performance characteristics of the satellite switch matrix are presented.     

Synthesis of some new diarylsulphides and diarylsulphones containing a quinazol-4-one moiety

4-Amino-4′-nitrodiphenylsulphide and 4-amino-2′-nitrodiphenyl sulphide ( I ) were smoothly condensed with 2-methyl-3,1-benzoxazin-4-one ( II ) to produce the corresponding 2-methyl-3-diphenylsulphidoquinazol-4-ones ( III ). 2-Styryl-3-diphenylsulphidoquinazol-4-ones ( IV ) were prepared by heating III with the appropriate aromatic aldehydes using piperidine as a basic catalyst. Compounds IV oxidised easily in a hydrogen peroxide-glacial acetic acid mixture to produce the corresponding sulphones ( V ). The constitution of some of the prepared products is discussed in the light of their infrared and ultraviolet spectra. The biological activities of some of these compounds were tested.     

The dielectric behaviour of lithium acetylacetonate

The dielectric constant and loss tangent of lithium acetylacetonate [Li(ac.ac)] have been measured at different frequencies for different temperatures. The results show that the dielectric behaviour of Li(ac.ac) is different from that of Na(ac.ac) and K(ac.ac) which exhibit a ferroelectric-like behaviour. The activation energy of Li (ac.ac) was found to be 0.54 eV, nearly half the value for K(ac.ac). The infrared absorption spectra of Li(ac.ac) shows that in this compound the lithium metal resembles group II rather than group I.     

A Fast Parallel Frequency-Domain Watermarking Algorithm

The aim of this research is to develop a faster watermarking algorithm based on the frequency domain. A sequential algorithm is picked, implemented, and parallelism is exploited in order to achieve a shorter execution time. Both DWT （discrete wavelet transform） and DCT （discrete cosine transform） are applied. Frequency domain watermarking techniques are known to be more robust. In addition, the algorithm falls under the bling category which implies a higher degree of security. A quad-core Intel Core TM i7-3630QM processor is used. The CPU （central processing unit） is 2.4 GHz and 6 GB RAM. MATLAB R2012a is used under Microsoft Windows 7 operating system. Two main lines of experiments are conducted; namely, the association of hosts to watermarks and the measurement of program speedup. Speedup is measured for both embedding and extraction operations on both dual-core and quad-core. Results reveal a gained speedup that reaches more than 200% as compared to the sequential algorithm.     

Nanoscale characterization of the dielectric charging phenomenon in PECVD silicon nitride thin films with various interfacial structures based on Kelvin probe force microscopy

This work presents a novel characterization methodology for the dielectric charging phenomenon in electrostatically driven MEMS devices using Kelvin probe force microscopy (KPFM). It has been used to study plasma-enhanced chemical vapor deposition (PECVD) silicon nitride thin films in view of application in electrostatic capacitive RF MEMS switches. The proposed technique takes the advantage of the atomic force microscope (AFM) tip to simulate charge injection through asperities, and then the induced surface potential is measured. The impact of bias amplitude, bias polarity, and bias duration employed during charge injection has been explored. The influence of various parameters on the charging/discharging processes has been investigated: dielectric film thickness, SiN(x) material deposition conditions, and under layers. Fourier transform infrared spectroscopy (FT-IR) and x-ray photoelectron spectroscopy (XPS) material characterization techniques have been used to determine the chemical bonds and compositions, respectively, of the SiN(x) films being investigated. The required samples for this technique consist only of thin dielectric films deposited over planar substrates, and no photolithography steps are required. Therefore, the proposed methodology provides a low cost and quite fast solution compared to other available characterization techniques of actual MEMS switches. Finally, the comparison between the KPFM results and the discharge current transients (DCT) measurements shows a quite good agreement.     

Effect of succinylation on the functional and physicochemical properties of alpha-globulin,the major protein fraction from Sesamum indicum L

alpha-Globulin the major protein fraction from Sesamum indicum was succinylated to different levels and the effect of the chemical modification was evaluated both on the functional and physicochemical properties. The results suggest that the pH of minimum solubility shifted to the more acidic side (pH approximately 4.5-5.5) for the succinylated alpha-globulin whereas for control alpha-globulin the pH of minimum solubility was 6.5. Succinylation also increased emulsion activity and emulsion stability of the protein. The emulsion stability increased from a control value of 53 +/- 3 s to a value of 122 +/- 5 s. Bulk density, water absorption capacity, oil absorption capacity, foam capacity and foam stability were evaluated in phosphate buffer (pH 7.0) containing 0.5 M sodium chloride and all these properties showed increased values as a result of succinylation. Ultracentrifugation studies showed that the % composition of 7S component increases with concomitant decrease in that of 11S fraction with the increase in percentage of succinylation. Further increase in succinylation resulted in only 2S component which is a dissociated form of 11S and/or 7S protein fractions. The fluorescence emission studies showed a decrease in the fluorescence emission intensity of alpha-globulin as a result of succinylation. The thermal stability of the protein molecule decreased due to progressive succinylation as indicated by decrease in the apparent thermal denaturation temperature from a control value of 84 to 62 degrees C at a succinylation level of 40%. These results suggest that succinylation improves the functional characteristics of alpha-globulin. Such changes in the functional properties have been attributed partly to the dissociation of the protein molecule at higher levels of succinylation and the increase in the net negative charge on the protein.     

Optical and electrical properties of Y3+ ion substituted orthorhombic mullite Y(x)Al(6−x) Si2O13 nanoparticles

Y³⁺ substituted mullite Y_(x)Al_(6?x)Si₂O₁₃ nanoparticles where x varied from 0.005 to 0.05 have been synthesized via co-precipitation technique. X-ray diffraction results revealed that orthorhombic mullite was the major phase in the samples of x = 0.0–0.025, whereas corundum α-Al₂O₃ was predominant at high Y³⁺-ion content of x = 0.05. Transmission electron microscope images showed orthorhombic-like structure for the pure sample. Meanwhile, the doped samples exhibited similar morphologies of larger particle sizes associated with small amount of glassy liquid phase. FT-IR spectrum evinced the formation of corundum particularly at high Y³⁺ ion content (5 %). The photoluminescence emission spectra were strongly affected by the Y³⁺ ion content. Moreover, mullite sample doped with 0.5 % Y³⁺ ion achieved the minimum electrical resistivity of 0.28 × 10⁹ Ω cm and the minimum dielectric loss value of 0.37 in the radiowave frequency region (10 MHz) as well as the minimum dielectric loss value of 0.41 in the microwave frequency region (1 GHz).