Functional polyamides. 3. Synthesis and chelating properties of a new poly(amide thioether)

Polymerization of β,β′-(ethylenedithio)dipropionitrile

1 IUPAC name: 4,7-dithiadecane dinitrile.

with formaldehyde in the presence of sulfuric acid was carried out in order to permit the synthesis of polymides containing thioether groups. The obtained poly(amide thioether)s were characterized; they coordinate mercury (II) with a high degree of selectivity.     

WCOT: A utility based lifetime metric for wireless sensor networks

Network lifetime is a novel performance metric which is derived in need to evaluate the networks that are composed of nodes with non-replenishable energy sources. Wireless Sensor Networks (WSNs) are the primary examples of such networks, in which elongating the network lifetime is the main concern. Optimal WSN design is highly dependent on the application scenario context. Correct quantification of the application specific network lifetime is a must to further optimize the design or to comparatively evaluate the proposed schemes – e.g. a legacy layered design vs. a cross-layer implementation. However, in practice, we observe that the focus is given on proposing sophisticated schemes to increase the energy efficiency, whereas only rudimentary lifetime metrics are employed to evaluate the outcome of this effort which compromises the correctness of the results. To realistically and correctly quantify the lifetime, we propose a utility based lifetime measurement framework called Weighted Cumulative Operational Time (WCOT). WCOT lets users incorporate the application dependence into the lifetime metric through its utility based interface. WCOT performs a weighted summation of time where utility values are the weights. With this mechanism, a more representative lifetime metric which maps the complete network behavior into a numeric value is obtained. This is in contrast with metrics which focus solely on certain milestones of the network functionality to quantify the lifetime which include the first node death, the last node death.     

Characterization of chemically sprayed CdO films on borate and phosphate glass substrates produced by melt-quenching technique

The properties of substrates used to deposit thin films are an important parameter in thin film production. Instead of using a commercial substrate, in this work, borate and phosphate glasses have been obtained by classic melt-quenching technique to be used as substrates for CdO films. Also, a microscope glass substrate has been used to compare the coating properties by other glass substrates. All films have been produced by Ultrasonic Spray Pyrolysis technique. The substrate temperature has been selected as 275 ± 5 °C. Thicknesses and some optical parameters such as refractive index and extinction coefficient have been determined by spectroscopic ellipsometry. Absorbance and transmittance spectra have been taken by UV/VIS spectrophotometer. Four-probe method has been used to determine the electrical resistivity values of the films. XRD investigations have shown that type of the substrate dramatically affects the characteristics of CdO films. CdO film deposited on phosphate glass substrate has the best structural quality. Atomic Force Microscope has been used to investigate the surface properties and roughness values of the films.     

Investigation of the effects of geometrical parameters on heat transfer from buried finned pipes

Heat transfer from finned pipes buried in the soil has been investigated using experimental, analytical and numerical techniques. The experimental setup consists of a ground source heat pump system and two separate ground heat exchangers. Constant surface temperature approach based on Carslaw and Jaeger’s theory study was used for calculating the heat transfer from the pipes analytically. The problem was modeled and solved using a CFD program numerically. Effects of the fin number, fin length and simulation time on the heat transfer rate have been investigated and compared with bare tube. A modified analytical formula was also proposed for finned pipes in this study.     

The effects of immunological castration against GnRH with recombinant OL protein (Ovalbumin-LHRH-7) on carcass and meat quality characteristics,histological appearance of testes and pituitary gland in Kıvırcık male lambs

The aims of the study were to investigate the effects of immunization against GnRH using OL protein (Ovalbumin-LHRH-7) on feedlot performance, carcass, meat quality and some reproductive traits in K?v?rc?k ram lambs. Ram lambs in the immunization (I, n = 7) group were immunized against GnRH using OL protein and boosted 2 weeks later. Control (C, n = 7) group was not treated. The animals were kept at pasture for 6 weeks after the first immunization, subjected to a 70 day fattening program, and then slaughtered. Growth performance, various carcass and meat quality characteristics were not affected from the immunization. GnRH immunization induced GnRH antibody production, suppressed testosterone production and testicular growth (P < 0.01). Testicular structure was negatively affected from the immunization, but not pituitary. These results suggest that immunization against GnRH with OL could be an alternative castration technique in ram lambs without negatively affecting carcass and meat quality characteristics.     

Thermal,mechanical and water adsorption properties of corn starch–carboxymethylcellulose/methylcellulose biodegradable films

The objective of this study was to investigate the effect of the addition of methylcellulose and carboxymethylcellulose on the thermal, mechanical and water adsorption properties of starch-based films plasticized with glycerol or polyethylene glycol (PEG). Mechanical tests showed that as the methylcellulose and carboxymethylcellulose proportion increased, starch films became more resistant to break, resulting in higher TS values. Besides there has been a positive effect on the elasticity of starch films realized by a considerable increase in E% values. Depending on the plasticizer type, either single or dual glass transitions were seen in DSC thermograms. One glass transition temperature was observed for films plasticized with glycerol, on the contrary, dual glass transitions were detected for PEG plasticized films. This behavior was attributed to the phase separation of the PEG. In addition, the presence of an endothermic peak in the thermograms of PEG plasticized films was taken as another indicator of the phase separation. As a result, it was suggested that PEG was not as compatible as glycerol with the composite polysaccharide matrix and plasticizer type was the main factor that shaped the thermal profiles of the film samples. Water adsorption isotherm data showed that samples displayed nonlinear sorption profile which is typical for hydrophilic films. In all films tested, equilibrium moisture contents, increased almost linearly up to a a_w of 0.65–0.85, beyond where a sharp increase was noted. Adsorption data was adequately fitted by BET and GAB models. Eventually, it can be concluded that film forming properties of starch can be improved by incorporation of methylcellulose and carboxymethylcellulose to the polymer matrix.     

Performance evaluation of a submerged membrane bioreactor for the treatment of brackish oil and natural gas field produced water

Produced water, which is co-produced during oil and gas manufacturing, represents one of the largest sources of oily wastewaters. Therefore, treatment of this produced water may improve the economic viability and lead to a new source of water for beneficial use. In this study a submerged hollow fiber membrane bioreactor (MBR) has been studied experimentally for the treatment of brackish oil and natural gas field produced water. This type of wastewater is also characterized with relatively moderate to high amount of salt, oil and total petroleum hydrocarbons (TPH). However, the bacteria which are growing in conventional activated sludge and MBR cannot survive at these strict conditions, therefore acclimation of the bacteria is of vital importance. The performance of the biological system, membrane permeability, the rate and extent of TPH biodegradability have been investigated under different sludge age and F/M ratios. The results obtained by gas chromatography analyses showed that the MBR system could be very effective in the removal of TPH from produced water and a significant improvement in the effluent quality was achieved.     

The effect of Sn concentration on some physical properties of zinc oxide films prepared by ultrasonic spray pyrolysis

The effect of Sn concentration on zinc oxide (ZnO) film properties has been investigated by depositing films with various Sn concentrations in the solution (Sn/Sn + Zn ratio from 0 to 50 at%) at a substrate temperature of 350°C by ultrasonic spray pyrolysis (USP) technique. The deposited films were characterized for their electrical, structural, morphological and elemental properties using current-voltage and conductivity-temperature measurements, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Electrical investigations showed that the resistivity of ZnO films decreases for lower Sn concentration (at 10%) and then increases for higher Sn concentration (at 30–50%). Also, depending on the increasing Sn concentration, energies of donor-like traps for ZnO films decreased and activation energy of donors for ZnO films increased. The XRD patterns showed that the as-deposited films have polycrystalline structure and the crystalline nature of the films was deteriorated with increasing Sn concentration and a shift to amorphous structure was seen. The effect of Sn concentration was to increase the surface roughening and change considerably the morphologies of ZnO films. The most homogenous surface was seen in ZnO films. EDS results showed that all elements in the starting solutions were in the solid films and Zn element is more dominant than Sn on the surfaces. After all investigations, it was determined that Sn incorporation dramatically modifies the properties of ZnO films. ZnO and ZnO:Sn (10 at%) films have a low resistivity and high transparency in the visible range and may be used as window material and antireflecting coating in solar cells while the other films may be used in gas sensors where high conductivity is unnecessary.