The complexes of para-chloranil as electron acceptor and the anions of amide, azide and cyanide as electron donors in aqueous ethanol as a solvent, were studied spectrophotometrically . The reactions lead to the formation of charge transfer complexes. The CT complexes were stable in excess acceptor concentration, while they were underwent another transformations in excess donors concentrations. Stoichiometries were determined, the molecular ratio was determined by continuous variation method (Job method) and is was 1:1 (donor: acceptor). The maximum wavelength (λ max.), the energy (hυCT), ionization potential (Ip) and activation energy (w ) of excited state for the charge transfer complexes were calculated, presented and discussed.
Moment invariants have wide applications in image recognition since they were proposed.
In this research, an experimental study was conducted to high light the impact of the exterior shape of a cylindrical body on the forced and free convection heat transfer coefficients when the body is hold in the entrance of an air duct. The impact of changing the body location within the air duct and the air speed are also demonstrated. The cylinders were manufactured with circular, triangular and square sections of copper for its high thermal conductivity with appropriate dimensions, while maintaining the surface area of all shapes to be the same. Each cylinder was heated to a certain temperature and put inside the duct at certain locations. The temperature of the cylinder was then monitored. The heat transfer coefficient were then cal
... Show MoreSpectrophotometric methods were developed for the determination of rantidine-HCl in pharmaceutical tablets. These methods were based on the reaction of DDQ and p-chloranil with rantidine-HCl, resulting in the formation of an orange-red and purple colored products which are quantified spectrophotometrically at 460 and 540nm in DDQ and p-chloranil, respectively. A graph of absorbance versus concentration show that Beer’s law is obeyed in a concentration ranges of 20-160 and (30-120)ïg/ml with molar absorptivities of 2.631 x 103 and 1.052 x 103l .mol-1-cm-1 for DDQ and p-chloranil, respectively. The optimum conditions for color development are described and
... Show MoreA new spectrophotometric flow injection method has been establish for the determintaions of some catecholaminedrugs
Amiodarone hydrochloride (AH) has been determined spectrophotometrically Using methyl orange (MO). In our previous researches MO was used for determination of Mexiletine Hydrochloride [1]. The method based on complexation between MO and AH. After shaking and diluting the complex solution with D.W, the pH was adjusted with NaOH and HCl to pH 3. The colored complex formed between AH and the reagent were transferred into separating funnels and extracted using 5.5ml CH2Cl2 and were shaken for (5 minutes). The extracted organic layer was used for preparation of the calibration curves for spectrophotometric measurements of AH at 434nm. The blanks were carried out in exactly the same way throughout the whole procedure.&n
... Show MoreA simple, rapid and sensitive spectrophotometirc method for the determination of trace amounts of promethazine hydrochloride in the aqueous solution is described. The method is based on the complexation of promethazine hydrochloride with In (III) in the presence of sodium hydroxide to form an soluble product with maximum absorption at 304nm. Beer’s law is obeyed over the concentration range of (2- 20μg/ml) with molar absorptivity of (1.92× 103 L.mol-1 .cm -1 ). The optimum conditions for all development are described and the proposed method has been successfully applied for the determination of promethazine hydrochloride in bulk drug.
Inherent fluctuations in the availability of energy from renewables, particularly solar, remain a substantial impediment to their widespread deployment worldwide. Employing phase-change materials (PCMs) as media, saving energy for later consumption, offers a promising solution for overcoming the problem. However, the heat conductivities of most PCMs are limited, which severely limits the energy storage potential of these materials. This study suggests employing circular fins with staggered distribution to achieve improved thermal response rates of PCM in a vertical triple-tube heat exchanger involving two opposite flow streams of the heat-transfer fluid (HTF). Since heat diffusion is not the same at various portions of the PCM unit,
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