Effect Of Alkali Concentration Research Articles

Comparison of Alkali and Conventional Corn Wet‐Milling: 1‐kg Procedures

ABSTRACTAn alkali corn wet‐milling process was developed to evaluate the process as a method to produce high purity corn starch and coproducts with added value. Using a single hybrid (R1064 × LH59), the effects of alkali concentration (0.18–0.82% NaOH), time (29–61 min), and temperature (36–75°C) were investigated. Starch yield was not affected by steep time or temperature. Starch yield was optimal at 65.2% using 0.5% alkali. Increasing the concentration of alkali to 0.82% or decreasing it to 0.18% caused a decrease in starch yield of 8–10 percentage points. Other wet‐milling products (fiber, germ, and gluten) also were affected. Steep conditions of 0.5% NaOH, 60 min, and 45°C gave optimal starch yield. Comparisons between alkali and sulfur dioxide wet‐milling processes, using 1‐kg sample size, were performed on 10 commercial yellow dent corn hybrids. The alkali process averaged 1.7 percentage points more starch than the sulfur dioxide process. Each hybrid had a higher starch yield when wet‐milled with the alkali method. Alkali wet‐milling produced pure corn starch with <0.30% protein (db).

Application of sonic energy to caustic cleaning of coals

The combined effect of sonic energy and sodium hydroxide on the desulphurisation of different high sulphur and high ash content coals has been investigated in the temperature range from ambient to 60°C and at atmospheric pressure. The sonication of coal samples led to a maximum reduction of 59 wt.% in total sulphur in a low rank coal, while 13 to 22 wt.% of total sulphur was removed from other sub-bituminous coals by employing a 1 M NaOH solution at 30°C. Leaching under these conditions, a reduction of 53 wt.% in ash was achieved in a low ash content (6.8 wt.%) coal compared with 5–25 wt.% for high ash content coals. The effects of alkali concentration, coal particle size, temperature and time on the demineralisation efficiency of coals were investigated.

Low-temperature dynamics of inorganic glasses Electrical conductivity against nuclear spin relaxation

Abstract At low temperatures, nuclear spin relaxation (NSR) can be related to electrical conductivity in various inorganic oxide glasses by the fluctuation-dissipation theorem. The results indicate a common physical origin of the relaxation mechanism owing to fluctuating charges. In comparison, however, in heavy metal fluoride glasses, NSR is shown to detect additional fluctuations which are not observed by. conductivity experiments. The underlying relaxation process is caused by nuclear magnetic fluctuations without any accompanying charge motions. Both dielectric and NSR responses can be explained in terms of thermally activated excitations of asymmetric double-well potential (ADWP) configurations intrinsic to highly disordered solids. The ADWP configurations are characterized from the effect of alkali concentration and size on the low-temperature conductivity. The asymmetry of ADWP configurations is determined primarily by the elastic strains in the structure.

The nutritive value of alkali-treated cocoa husk meal in broiler chick diets

The effect of alkali concentration and treatment on the chemical composition of cocoapod husk (CPH) was investigated. This was followed by the incorporation of the alkalitreated CPH (TCPH) in broiler starter diets to investigate its nutritive value. Alkali was obtained from cocoa-pod ash, 7.35 g of which was found to be equivalent in alkali strength to 1 g sodium hydroxide. Longer alkali treatment time (48 h) yielded similar effects to those produced after 24 h. Increasing alkali concentration (5, 10, 15 and 20 g kg −1) decreased the amounts of crude fibre, hemicellulose, cellulose and crude protein, but increased total ash, Na, Cu, Fe, Mn and Zn contents of CPH. An alkali concentration of 10 g kg −1 (which appeared most balanced in its effect on the chemical contents of CPH) was employed in a 24 h-treatment of the husks used in the feeding trial. TCPH was included in the diets at concentrations of 0, 50, 100 and 150 g kg −1. Each diet was fed to triplicate groups of 15, day-old broiler chicks for 28 days. The results showed that increasing TCPH level up to 100 g kg −1 did not significantly reduce growth performance and apparent digestibility of nutrients. Dietary inclusion of TCPH at 150 g kg −1 significantly ( P < 0.05) reduced weight gain and feed efficiency compared with those on the control diet (weight gain, 497.0 g vs. 520.3 g; feed efficiency, 2.61 vs. 2.12, respectively). Also the apparent digestibilities of crude protein (0.80) and crude fat (0.90) for the control diet decreased significantly ( P < 0.05) to 0.75 and 0.84, respectively, for the 150 g kg −1 TCPH diet. Water consumption of chicks increased with increasing TCPH level. It was concluded that in order to effect the potential upgrading of the nutritive value of CPH, it is necessary to remove salt deposition and residual alkali, which may have masked the effect of alkali treatment.

Dynamic modeling and optimal state estimation using extended Kalman filter for a kraft pulping digester

A non-linear dynamic model of delignification has been developed for kraft pulping of Pinus casia wood, based on 36 batch experiments at various operating conditions. Further, the validity of the mathematical model is ascertainted with independent experiments. Extended Kalman filter and nonlinear observer are applied to estimate lignin and carbohydrate contents during pulping by employing the developed model in conjunction with the effective alkali concentration as available process measurement.

Recovery of residual oil using the alkali/surfactant/polymer process: effect of alkali concentration

An experimental study was conducted to examine the effectiveness of sodium carbonate in alkali, surfactant and polymer combined slugs in recovering waterflood residual oil. The effects of sodium carbonate concentration on the slug viscosity, interfacial tension, and phase behavior were first examined. Core flood experiments were conducted with unfired linear Berea sandstone cores. The incremental oil recovery, oil cut, residual resistance factor, and chemical propagation were measured for each flood. A significant oil bank was formed for all combined slugs having sodium carbonate concentration ≥1 wt%. The incremental oil recovery, oil cut and the injectivity of the combined slugs greatly improved as sodium carbonate concentration was increased. The effect of sodium carbonate concentration on chemical propagation was dramatic for the synthetic surfactant; a slight delay in surfactant breakthrough and a much slower rate of surfactant propagation were observed at high sodium carbonate concentrations. The results obtained in the present study indicate that the residual oil was recovered by two mechanisms: low interfacial tension and wettability reversal. The former mechanism is dominant at sodium carbonate concentrations ≤1 wt%, whereas the latter plays an important role only at high sodium carbonate concentrations.

Reactor analysis of a chlor—alkali membrane cell

An analysis based on the concept of a continuous stirred tank reactor (CSTR) has been made for an ion exchange membrane chlor—alkali cell. The effects of alkali concentration, current density and temperature on the power consumption are examined with mass, energy and voltage balances. Numerical results are presented for cell voltage, power consumption and heat requirements for a cell with Nafion-295 and Nafion-901 membranes. The results of these analyses are compared to those of a bench scale experiment using Nafion-901 as the membrane.

クラフト蒸解に関する速度論的研究 有効アルカリの消費速度

A rate of effective alkali consumption by wood components has been studied in the bulk delignification phase and the final phase of kraft cooking. Experimentally, kraft cooking was carried out on matchstick-like wood chips. Black liquor was titrated potentiometrically with HCl.It was found that the rate of effective alkali consumption was expressed as-d [OH-] e/dt=1/α·t-1where [OH-] e was effective alkali concentration at cooking time t, 1/α was a constant. The apparent activation energy of effective alkali consumption for kraft cooking carried out on wood with 14.0 and 15.8% effective alkali was 41.3 and 35.8 kcal·mol-1 respectively. However, effective alkali was consumed by degradative products from both lignin and carbohydrates in the bulk delignification phase and the final phase, the concentration of residual effective alkali was closely correlated to the extent of delignification. A known kinetic equation for delignification is not applicable to conditions of time-varying liquor concentration. Consequently, the above rate equation for effective alkali consumption is useful to describe the kraft pulping process quantita-tively together with a kinetic equation of delignification.

Action of aqueous sodium hydroxide on glucose syrups

The effect of alkali concentration on the degradation of glucose syrups is studied and alkali numbers for a series of glucose syrup fractions and commercial glucose syrups are determined. Volatile acidity produced is shown to be dependent on alkali concentration and volatile acidity values are determined on 28 samples. Again, as DE increases, so does volatile acidity. Two methods of analysis of glucose syrup are described, the first concerning the determination of the DE of glucose syrups and the second a theoretical example of the analysis of glucose syrup-sucrose mixtures.

Photoinduced reactions—L : Photolysis of halogenophenols in aqueous alkali and in aqueous cyanide

On irradiation in aqueous alkali, several monohalogenophenols were found to react in several ways depending on the position of a substituent halogen. p-Substituted halogenophenols yielded 2,4′-dihydroxy-4-halogenodiphenyl (I). 2,4′-dihydroxydiphenyl (II), and phenol (III), in addition to the already known products, hydroquinone (V) and 4,4′-dihydroxydiphenyl (IV). The yield of V decreased in the order of Cl > Br > I, while those of III and IV increased in the order of Cl < Br < I. The effects of alkali concentration and of temperature on the reaction were examined with p-chlorophenol. Higher concentration of alkali and higher temperature accelerated the reaction and favoured the formation of III and V. m-Chlorophenol, on the other hand. gave resorcinol in high yield, which shows the electrophilic nature of the excited m-chlorophenol. o-Chlorophenol gave only a complex mixture of products including a large amount of a resinous material. Irradiation of p-halogenophenols in aqueous cyanide yielded p-cyanophenol in good yields, accompanied by a small amount of hydroquinone, while irradiation of m-chlorophenol gave resorcinol in high yield, accompanied by a small amount of m-cyanophenol. o-Chlorophenol again gave only intractable products. Reactions with a light at 2537 Å and with that over 2900 Å were substantially the same. although longer period of irradiation was required in the latter case. Some mechanistic discussions are included.

Circularity of Cotton Fibers and the Effects of Alkali Concentration and Tension on the Changes Brought About in it During Mercerization

This paper deals with changes in the circularity of cotton fibers when slick- mercerized and under different tensions in various concentrations of caustic soda. The percent increase in circularity depends on the circularity of the raw cotton. The Adder ley method for determining the circularity can give fairly reliable results for purposes of comparison.

The analysis of tissue phospholipids: hydrolysis procedure and results with pig liver

A procedure for the hydrolysis of phospholipids is described. The effect of alkali concentration, organic solvents, and length of hydrolysis have been studied. The initial reaction in the preferred solvent system appears to be a methanolysis. The phospholipids are converted quantitatively into water-soluble phosphates, which are separated and estimated by ion-exchange chromatography. In this way phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol may be determined in liver tissue.

Corrosion of silicate glasses by alkaline solutions Communication 5. Effect of alkali concentration on the degree of destruction of glass

1. An increase in concentration of sodium hydroxide solutions from 0.5 to 10 N affects the degree of corrosion of silicate glasses variously: glasses rich in silica are attacked proportionally to the alkali concentration, the destructive action on glasses rich in lead, zinc, cadmium, or magnesium is at first increased and then retarded as a result of the accumulation in the solution of anion-inhibitors and the formation of protective layers of magnesium hydroxide, and glasses rich in calcium, strontium, or bariumare attacked to the same extent by all solutions in the concentration range investigated. 2. An increase in the concentration of strontium or barium hydroxide solutions leads to a decrease in the corrosion of silicate glasses as a result of the formation on the surface of the glass of alkali-stable compounds.