Numerical investigation of combustion characteristics in an oxygen transport reactor

The paper presents a numerical investigation of thermal characteristics of oxyfuel combustion in an oxygen transport reactor (OTR). The reactor is made of a combustion chamber of tubular shape and surrounded by an annular air flow compartment. The walls of the combustion chamber are made of dense, nonporous, mixed‐conducting ceramic membranes that only allow oxygen permeation from the annular air compartment into the combustion chamber. A mixture of CO₂ and CH₄ (sweep gas) enters the reactor from one side and mixes with the oxygen permeating through the ion transport membrane. The resulting combustion products (composed of H₂O and CO₂) are discharged from the other side of the reactor. The modeling of the flow process is based on a numerical solution of the conservation equations of mass, momentum, energy and species in the axi‐symmetric flow domain. The membrane is modeled as a selective layer in which the oxygen permeation depends on the prevailing temperatures as well as the oxygen partial pressure at both sides of the membrane. The comparison between reactive and separation‐only OTR units showed that combining reaction and separation increases significantly O₂ permeation rate to about 2.5 times under the assumptions given herein. Uniform axial temperature of about 1250 K is achieved in most of the reactor length with high CH₄ conversion of 75% to 35% for CH₄/CO₂ mass ratio ranging from 0.5/0.5 to 1.0/0. Since the thermal resistance of these membranes is low, the heat of reaction is mostly transferred to the air side with a portion used to heat the O₂ permeating flux. Copyright © 2013 John Wiley & Sons, Ltd.     

Dyeing properties of cationized and non-cationized cotton fabrics dyed with Vitis vinifera L. leaves extract

This study lays bare two main objectives. The first is to determine the amount of anthocyanins in the leaves of Vitis vinifera L. by the spectrophotometric method and the second is to dye cationized and non-cationized cotton fabrics with the V. vinifera L. leaves aqueous extract. We have thoroughly investigated the effects of dye bath pH and temperature on the dyeing proprieties of the aforementioned fabrics. The color strength (K/S value) of dyed cationized cotton fabrics (K/S = 12) has been better than the non-cationized ones (K/S = 4). Experimental results show that the fastness properties of dyed cationized cotton fabrics range from average to good. We find that the cationization of cotton fabrics has largely improved the dyeability and fastness properties of cotton fabrics dyed with V. vinifera L. leaves aqueous extract.     

Characteristics of low‐fat beefburgers as influenced by various types of wheat fibres

Hydrated wheat fibres (bran and white and red beeswings) were added at three levels (50, 100 and 150 g kg⁻¹ ) to beefburger as replacement for fat and evaluated for chemical and physical properties, energy content and sensory traits. Uncooked and cooked beefburgers formulated with wheat fibres had higher (P⩽0.05) moisture, protein and carbohydrate contents and lower (P⩽0.05) fat contents than that of the control. However, ash content was increased (P>0.05) by the addition of wheat fibres. The cholesterol content of uncooked and cooked beefburgers decreased as level of wheat fibres increased or fat content decreased. The addition of wheat fibres reduced the cholesterol content from 6 to 45% for uncooked and cooked beefburgers. The energy content of uncooked and cooked beefburgers was lower (P ⩽0.05) than that of control by between and 6 and 41%. The cooking yield and reduction in diameter of beefburgers were significantly (P⩽0.05) improved by the addition of wheat fibres. The addition of red and white beeswings showed an improvement in the texture trait. Colour traits, tenderness, juiciness, connective tissue amount, beef flavour intensity and overall palatability were not affected by the addition of wheat fibres to beefburgers. Hydrated wheat fibres can be used successfully as a fat substitute in ground meat products. © 1999 Society of Chemical Industry     

Studies on 1,2,4-triazine derivatives. III. The Behaviour of some Derivatives of 1,2,4-Triazine toward diazomethane,amines, ethyl monobromoacetate and tetra-O-acetyl-α-D-glucopyranosyl bromide

The reaction of diazomethane with 6-phenyl-3-thioxo-5-oxo-2,3,4,5-tetrahydro-1,2,4-triazine 2a , and with 6-phenyl-3-methylmercapto-5-oxo-4,5-dihydro-1,2-triazine 3a effected N-methylation to 2b and 3b , respectively. Compound 3a and 3-methyl-mercapto-5, 6-diphenyl-1,2,4,-triazine 4a react with amines to give 3-N-substituted-amino-triazines 5a–h and 6a–h , respectively. 3-Mercapto-5,6-diphenyl-1,2,4-triazine 4b underwent S-alkylation with ethyl monobromoacetate and with tetra-O-acetyl-α-D-glucopyraosyl bromide.     

Some New Heterocyclic Sulphonates with potential antimicrobial activity

4-(Phenylhydrazono-4′-benzenesulphonato)-3-methyl-2-pyrazolin-5-one ( 2 ) was prepared by treating 4-(4′-hydroxyphenylhydrazono)-3-methyl-2-pyrazolin-5-one ( 1 ) with benzenesulphonyl chloride. Heating 2 with acetic anhydride, chloroacetyl chloride and benzenesulphonyl chloride afforded the N-acetyl ( 3 ), N-chloroacetyl ( 4 ) and O-benzenesulphonyl ( 5 ) derivatives, respectively. 2 reacted with benzenesulphonyl chloride under cooling conditions to give the N-benzenesulphonyl derivative ( 6 ). 2 undergoes Mannich reaction to give the N-Mannich base ( 7 ). Reaction of 2 with formaldehyde in methanol afforded the N-hydroxymethyl derivative ( 8 ) which undergoes condensation with ethyl acetoacetate, ethyl cyanoacetate and malononitrile to give compounds 9 , 10 and 11 respectively. The antimicrobial activity of these products against gram-positive (+ve), gram-negative (−ve) bacteria and fungi was screened. They showed potential bactericidal activity and some of them exhibited high fungicidal activity.     

Reactivity of 4-acetyl-3-chloro-5,6-diphenylpyridazine towards some nucleophilic reagents,Synthesis of Some Fused Pyridazine Derivatives

4-Acetyl-3-chloro-5,6-diphenylpyridazine ( 1 ), prepared by the action of phosphorus oxychloride on 4-acetyl-5,6-diphenylpyridazin-3(2H)-one ( 2 ), reacts with hydrazine hydrate and phenylhydrazine to give the pyrazolinopyridazine derivatives ( 3a , b ) respectively. Reaction of 1 with hydroxylamine hydrochloride gave the isoxazolopyridazine derivative ( 5 ), while its reaction with sodium azide in dimethyl formamide gave the tetrazolopyridazine derivative ( 8 ). Primary amines react with 1 to give either 9 or 10 depending upon the reaction conditions. Treatment of 1 with piperidine or morpholine gave the products 11a , b , respectivly. 4-Acetyl-5,6-diphenylpyridazin-3(2H)-thione ( 13 ) was readily obtained by the action of thiourea on ethanolic solution of 1 . The reactions of 1 with phenols were also investigated.