A new hetrocyclic liquid crystal compounds containing 1,3,4-oxadiazole with different substituted in para position (Bromo, Chloro, Nitro and Methyl) were synthesized and characterized by melting points, FTIR Spectroscopy and 1HNMR spectroscopy for [Cl-SR6] and [NO2-SR6] compounds. The liquid crystalline properties of the synthesized compounds were studied by using hot-stage polarizing optical microscopy (POM), so they determined the transition enthalpies and entropies by using differential scanning calorimetery (DSC). All of the compounds show mesomorphic properties. The compounds [Br-SR6], [Cl-SR6] and [NO2SR6] exhibit an enantiotropic dimorphism smectic (Sm) phase, while the compounds [MeSR6] showed nematic (N) phase throw cooling only. Continuously, permittivity dielectric properties, electrical conductivity, relaxation times and activation energies have been studied in the range of temperatures (70-150)°C at two frequencies (500) Hz and (1000) Hz. Generally, the results show the dielectric permittivity and relaxation time values increasing when raising temperature, while electrical conductivity values decrease with increasing temperature. The activation energy values were determined in terms of the Arrhenius plot.
The distribution of chilled water flow rate in terminal unit is a major factor used to evaluate the performance of central air conditioning unit. In this work, a theoretical chilled water distribution in the terminal units has been studied to predict the optimum heat performance of terminal unit. The central Air-conditioning unit model consists of cooling/ heating coil (three units), chilled water source (chiller), three-way and two-way valve with bypass, piping network, and pump. The term of optimization in terminal unit ingredient has two categories, the first is the uniform of the water flow rate representing in statically permanents standard deviation (minimum value) and the second category is the maximum heat transfer rate fro
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The ability of crystals protein production was studied in local isolate Bacillus
thuringiensis by microscope examination, and the crystals protein production were seen
after 48 hour from growth starting, the study of plasmid profile of the isolate using gel
electrophoresis technique in 0.7% of agaros gel, revealed that it had one Mega plasmid
band, the plasmid role in production of crystals protein was studied by using conjugation experiments, that they applied on the local isolate B. thuringiensis which was crystals
protein producer and Rifamycin sensitive as donor cells, with Bacillus spp. which didn’t
produce crystals protein and Rifamycin resistance as recipient cells. Conjugation
experiments assured the transm
(1)
The micellization for an aqueous binary mixed system of Nonyl Phenol Ethoxylate ( NPE ) and Dehyquarte E-CA (DE-CA) were studied by means of surface tension measurement. The surface tension was measured for the solutions of the single and five mixed systems at 25ᵒC in order to determine critical micellization concentrations (CMC), surface excesses (Γ), and the surface area occupied by a molecule (Am) as a function of mole fraction of (NPE). The CMC,s values obtained decrease with increasing mole fraction of NPE in the mixture, and the synergism was observed at 0.9 mole fraction. Based on the regular solution theory, the compositions of the micellar phase (X1m) and the interaction parameter in micelles (βm) were calculated, and the re
... Show MoreAn investigation was conducted for the study of extraction of metal ions using aqueous biphasic systems. The extraction of iron, zinc and copper from aqueous sulphate media at different kinds of extractants SCN− , Cl- and I- , different values of pH of the feed solution, phase ratio, concentration of metals, concentration of extractant, concentration of polymer, and concentration of salt was investigated. Atomic absorption spectrophotometer was used to measure the concentration of iron, zinc and copper in the aqueous phase throughout the experiments. The results of the extraction experiments showed the use of SCN− as extractant, pH=2.5, phase ratio=1.5, concentration of metals 1g/l, concentration of extractant 0.06 %, concentration o
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In this work, two cone-inverted cylindrical and cross-hybrid dielectric resonator antennas are stacked and excited by the coaxial probe method with an operating standard resonant frequency of 5.438 GHz. A drawback of these standard Dielectric Resonator Antennas (DRAs) is their narrow bandwidth. For good antenna performance, a stacked DR geometry and a thick dielectric substrate having a low dielectric constant are desired since this provides large bandwidth, better radiation power, reduces conductor loss and nonappearance of surface waves. Many approaches, such as changing the shape of the dielectric resonator, have been used to enhance bandwidth. Using DRA, having the lowest dielectric constant, increases the bandwidth and the electroma
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In this work the poly vinyl imides were prepared as thermal l y stable polymers by modified PVC and PVC copolymers \'lith different cyclic imides such as naphtha imide, phtbal imide, male imide and succin imide as a pendant groups.
This method gave new polyimides, from considered especially plastic because of their outstanding high performance properties. As
such, they are priced well above commodity polymers such as PVC
and PVC copolymers.
All the prepared polymers were characterized by IR, UV spectroscopy, elemental analysis and chemical reactions, and thermal analysis such as DTA and TG. Physical properties and the viscosities for all prepared polyimides were determined by using DMF as a sol
... Show MoreI have studied the relationship between blood groups in humans and disease Cutaneous injury for the first time in Iraq study showed the presence of a significant statistical relationship between them leather Bmsoy in hospitals in Baghdad and its suburbs
In the present paper, we have introduced some new definitions On D- compact topological group and D-L. compact topological group for the compactification in topological spaces and groups, we obtain some results related to D- compact topological group and D-L. compact topological group.
In the present paper, we have introduced some new definitions On D- compact topological group and D-L. compact topological group for the compactification in topological spaces and groups, we obtain some results related to D- compact topological group and D-L. compact topological group.