Effects Of Feed Composition Research Articles

Fixed-bed adsorption of acid gases on a macroreticular ion-exchange resin

The fixed-bed adsorption behavior of sulfur dioxide and carbon dioxide on a macroreticular, styrene-divinylbenzene, anion-exchange resin has been studied. The effects of feed composition, feed flow rate, bed length, and bed temperature on bed performance have been determined experimentally. It has been established that the bed has a low capacity for carbon dioxide, and heat of sorption effects are negligible. In contrast, a high adsorption capacity was observed for sulfur dioxide, with significant heat of sorption effects. At sulfur dioxide loadings typical of flue gases from high sulfur (4 wt. %) coals, a bed capacity of about 1500 bed volumes was obtained. Selectivity for sulfur dioxide over carbon dioxide was also found to be very high, with a separation factor of about 1000. The fixed-bed adsorption process has been modeled with the equilibrium coherence theory of chromatography, using a pseudo-isothermal approach that establishes the effective adsorption temperature from the feed composition. This approach has been used to predict bed behavior for frontal development with binary mixtures, and for elution development. It was found that the method is effective for the frontal case, but has limitations with regard to elution development.

Effect of feed composition, aerobic volume fraction and recycle rate on nitrogen removal in the single-sludge system

A recently developed and experimentally validated model was used to delineate the effects of various design and operation parameters on the performance of single-sludge systems. Model simulation resulted in charts which illustrate the mutual effects of raw feed COD/ammonia ratio, aerobic volume fraction and recycle rate. The most significant phenomenon, observed experimentally and supported by the simulation, is that increasing recycle may lead to increased effluent nitrate. This situation may occur under low raw COD/ammonia ratios, whereas for high COD/ammonia ratios, as in most domestic wastes, an opposite phenomenon occurs. This means that the recycle has an optimum value which depends on feed composition and on aerobic/anoxic fractionation of the system. The presence of viable cells in the feed in significant numbers affects the composition of biomass in the system and the removal of nitrogen compounds.

The influence of bovine oocyte type on in vitro-fertilization and subsequent development in vitro

Microalgae technology is attractive for simultaneously treating wastewater and producing valuable biomass. However, biofuel application demands a very low net-energy input that can hardly be fulfilled. Therefore, exploration of a more direct-use of microalgae biomass and selection of appropriate microalgae species are necessary to fine-tune viable applications. This study assesses performance of sequencing batch membrane photobioreactors (SB-MPBRs) for simultaneously polishing secondary effluent by cultivating Staurastrum sp., a species suitable as aquaculture feed. The effect of feed composition (high and low phosphorous, P) on microalgae growth, membrane fouling propensity, nutrient removal, as well as oxygen enrichment capacity were evaluated. Overall results demonstrate the effectiveness of SB-MPBR to cultivate Staurastrum sp. in secondary effluent by achieving biomass concentration of 0.45 and 0.6 g/L and very low nutrients concentrations in the effluents (≈ 0, 10 and 2 mg/L, for chemical oxygen demand (COD), TN and TP respectively). The actual biomass productivity of the SM-MPBRS are 40.0 and 30.0 g/(day m3) for the low-P and high-P feeds, corresponding to production costs of 11.3 and 15.1 $/kg biomass, respectively. Low-P feed results in a slightly higher biomass productivity of 33% compare to high-P feed, but slightly higher fouling propensity. The growth in both SB-MPBRS seems to be limited by the inorganic carbon supply. Too-short HRT leads to nutrients accumulation of the nutrients and eventually reduced their removal efficiencies. Overall results show a new cultivation method for aquaculture feed while at the same time polish secondary effluent and enrich its oxygen concentration.

Effects of Feed Composition, Feed Moisture, and Barrel Temperature on the Physical and Rheological Properties of Snack‐like Products Prepared from Cowpea and Sorghum Flours by Extrusion

ABSTRACTDecorticated meals made from grain sorghum and cowpeas and 33‐67% blends of the two were hydrated to 20.5, 23.0, and 25% moisture and extruded at 175°, 190°, and 205°C. Effects of composition, feed moisture, and barrel temperature on product temperature, residence time, expansion ratio, unit bulk density, product moisture, Warner‐Bratzler shear force, stress and energy and sensory hardness and brittleness were determined. Most properties could be described by a generalized second order model. Individual models differed widely; however, composition (or its interaction terms) was significant in most cases in which it was a variable. Considering all compositions, temperature was most often significant. Effect of moisture was more significant as the proportion of cowpea in the mixtures increased. Textural properties were compared to those of three commercial snack foods. Experimental extrudates were somewhat tougher than commercial snacks although not drastically different from them.

Pervaporation separation of ethanol-water mixtures using grafted poly(acrylic acid)-nylon 6 membranes

Gamma-ray induced grafted poly(acrylic acid) (PAA)-Nylon-6 membranes were prepared and tested for the pervaporation separation of ethanol-water mixtures. Two methods were used for the pervaporation of the grafted membranes. In method-1, the substrate was first crosslinked and then irradiated in aqueous solutions containing acrylic acid and 0.04 M cupric sulphate. In method-2, the substrate was first irradiated in the grafting solution and then crosslinked in 10 weight % aqueous Al(NO 3)7-9H 20 solution. The best results were obtained from graft copolymer membranes with PAA content between 15 and 20 weight %, which gave separation factors ranging from 10–25 and permeation rates of 30–250 g/m2 hr. The effects of monomer concentration and the radiation dose on the percent grafting as well as the effects of feed composition on the separation factors and the permeation rates have also been investigated.

A Dynamic Simulation Model for Growth of the African Catfish, Clarias Gariepinus Burchell 1822. II. Effect of Feed Composition on Growth and Energy Metabolism

To investigate the effect of feed composition on growth of the African catfish a dynamic simulation model was adapted. The effect of feed composition studied was restricted to the effect of the macronutrients, i.e. protein, fat and carbohydratesMost parameters used in the model were derived from literature. Parameters, which were expected to have specific values for the species used or which could not be derived from the literature, were calibrated with experimental results. Results used for calibration originate from a 84day feeding trial with twenty different semi-moist diets. Protein content of these diets varied from 20 to 60% and fat content from 0 to 38%Data used to test the model originate from balance respiration experiments. In these experiments dietary protein content varied from 20 to 40% and fat content from 4 to 29%. A dry pelleted feed was usedThe test results of the model for growth, protein and fat gain, and oxygen consumption were compared with the independently obtained results of the balance respiration experiments. The predicted values are in agreement with the observed values, except for the diets with the highest fat content. At these diets predictions are overestimated. During the modelling procedures it became apparent that feed intake is influenced by the fat percentage of the fish. Fat fish consume less than leaner fish of the same weight.It is concluded that the model predicts reasonably well effects of feed composition on growth

Effect of feed composition on product distribution in the catalytic conversion of trimethylbenzenes over [formula omitted] zeolite catalyst

Three different pairs of trimethylbenzenes, namely pseudocumene and mesitylene, pseudocumene and hemimellitene, and mesitylene and hemimellitene, were simultaneously catalysed by ( Pt La )- Y zeolite, with and without the addition of toluene. The catalytic conversion was carried out under atmospheric pressure in a microreactor in the temperature range 350°–425°C, within which cracking is almost absent. The percentage conversion of these different feed compositions increased with increase in reaction temperature. The rate of increase was in the following order: pseudocumene + mesitylene > pseudocumene + hemimellitene > mesitylene + hemimellitene. The maximum concentration of xylenes was achieved at 400°C. The addition of toluene to each of these trimethylbenzene pairs resulted in an increase in xylene (based on trimethylbenzenes and toluene converted). Similarly, a mixture of pseudocumene, mesitylene and hemimellitene of different molar ratios was studied with and without the addition of toluene. It was concluded that the feed composition of trimethylbenzenes influences the total percentage of xylenes in the product.

A dynamic simulation model for growth of the African catfish, Clarias gariepinus (Burchell 1822) : II. Effect of feed composition on growth and energy metabolism

A dynamic simulation model was adapted to investigate the effect of feed composition on growth of Clarias gariepinus. The effect of feed composition was restricted to that of the macronutrients, i.e. protein, fat and carbohydrates. Most parameters used in the model were derived from the literature. Parameters which were expected to have specific values for the species used, or which could not be derived from the literature, were calibrated with experimental results. Results used for calibration originate from an 84-day feeding trial with 20 different semi-moist diets. The protein content of these varied from 20 to 60% and the fat content from 0 to 38%. Data used to test the model originated from balance respiration experiments. In these experiments dietary protein content varied from 20 to 40% and fat content from 4 to 29%. A dry pelleted feed was used in these experiments. The test results of the model for fresh weight gain, protein gain, fat gain and oxygen consumption were compared with the independently obtained results of the balance respiration experiments. It is concluded that the model predicts reasonably well the effects of feed composition on growth and growth composition. The predicted values are in agreement with the observed values, except for the diets with the highest fat content. With these diets the predictions are overestimated. During the modelling procedure it became apparent that feed intake is influenced by the fat content of the fish biomass. Fat fish consume less than leaner fish of the same weight.

Effects of Feed Composition and Feeding Schedule on Growth and Development of Broiler Breeder Males

Two experiments were conducted to compare the effects of feeding broiler breeder males: 1) a 15 or 20% protein starter diet (0 to 4 weeks) and 2) varying levels of energy and protein on an every day (ED) or on an every other day (EOD) basis during the growing period (4 to 20 weeks). Weight gain and shank length at 28 days were less for males started on 15% protein in both experiments. In the first experiment, males fed diets containing 2.8 kcal metabolizable energy (ME)/g during the grower period weighed and gained more than those fed 2.0 kcal ME/g although total ME intake was the same. Males fed ED gained significantly more than those fed EOD. In the second experiment, males fed 15% protein during the grower period gained and weighed more than those fed 12 or 18% protein, and those fed 15% ED gained and weighed significantly more than those fed 20% EOD. In both experiments males fed ED were more feed efficient (as measured by gain/feed consumed) than males fed EOD but consuming the same amount of feed. Semen characteristics were not affected by feeding schedule or grower diet protein level. Fertility was higher in 3 of the 4 weeks sampled for males fed 15% ED. Results indicate that feeding schedule (ED vs. EOD) as well as nutrient intake influence body weight gains of broiler breeder males.

Observation on Methemoglobinaemia in Dairy Cows During Four Years

Lebeda M., J. Prikrylova: Observation on Methemoglobinaemia in Dairy Cows During Four Years. Acta vet. Brno, 54, 1985: 157-168. During four years of investigation (time periods A, B, C, D) methemoglobinaemia has been observed in venous blood of 2 812 dairy cows, out of which 1 687 were fed winter feed rations and 1 125 animals received summer feed rations (fresh grass). This disorder was noted in the 1st and 2nd lactation stage and in 8th-9.5th month of pregnancy. The average methemoglobin values (MHb) slightly exceeded the tolerance limit of 5 % hemoglobin. Neither in the entire populations nor in individual groups of cows a significant difference was observed between all summarized summer and winter seasons. The methomoglobin value during winter season in highly pregnant cows was observed to be significantly lower than that in lactating cows. The difference of feed rations had only a little influence upon the level of methemoglobin, the effect of feed composition and quality in individual years being, however, significant. The highest significance of methemoglobin concentration was observed in all cow groups in the summer season of the A period and in the following winter season of the B peri­ od. The highest concentration in both these periods was observed in cOws in the 2nd lactation stage (7.27 ± 1.47 % and 6.15 ± 1.84 % in winter and summer season, resp.). In the last two years (C and D) methemoglobin values decreased in all groups of cows, this being more pronounced in winter than in summer seasons. The influence of subclinical chronic methemoglobinaemia on the health condition of dairy cows and on economic parameters of husbandry is discussed. Cows, methemoglobin, summer and winter feeding, 1st cmd 2nd lactation stage, pregnancy. The values of methemoglobin presented in literature as being normal for healthy cattle vary considerably. According to Bartik and Rosival (1971) this value ranges from 0.3 to 1.7 % of total hemoglobin whereas Sporri and Stiinzi (1969) presented the value of 3-5 %. Penkov (1974 - quot. Lebeda et al. 1978) reported the values reaching up to 3.7 % of hemoglobin but in calves at most four days old. he found no methemoglobin. The tendency of the ))flormal(, or tolerable methemoglobin values to increase is associated with the intensification of agriculture and the consequence of which are the increased nitrate levels in soil, water and crop (see Garner

Effect of feed composition and operating conditions on catalyst deactivation and on product yield and quality during naphtha catalytic reforming

The effect of operating conditions and feed compositions on the yield and quality of reformate and on catalyst deactivation were studied for naphtha reforming over an industrial bimetallic reforming catalyst. The aromatics yield showed a maximum in the pressure range 7-10 bar, while the carbon deposition decreased with increasing pressure. Increasing temperature led to an increase in the yield of aromatics at the expense of reformate. Hydrogen: hydrocarbon ratios (H/HC) in the range 7-12.7 did not show any pronounced effect on reformate or aromatics yield: however, lower H/HC ratios (eg: 3.6), gave decreased aromatics and increased carbon. Quantitative correlations are developed for these observations and mechanistic arguments are presented to explain the results. Feed composition effect studies were carried out by using several naphtha blends having a wide variation in the paraffin, naphthene and aromatics content. At any reforming severity, yields of reformate and aromatics are higher and coke deposition is lower for a naphthene-rich naphtha. The temperature requirement for attaining a particular product quality (RONC) is lower for naphthene-rich naphtha than for paraffin-rich naphtha. Correlations between the reformate octane number and reformate yield have been obtained for different naphtha feed stocks.

Degradation of mimosine by rumen contents: effects of feed composition and Leucaena substrates

Samples of rumen fluid obtained from sheep that had been fed on different diets were fractionated into microorganism and supernatant fractions, and the former divided into bacteria-rich and protozoa-rich fractions. The fractions were evaluated for their ability to degrade purified mimosine during in vitro incubation. The rumen contents of sheep fed on a lucerne-oats mixture produced a more rapid degradation of mimosine than did that from sheep fed on lucerne hay, which was greater than that from a Digitaria pentrii diet. Most activity was in the bacteria-rich fraction for the lucerne-oats diet and in the protozoa-rich fraction for the other diets. The rate of degradation of endogenous mimosine in Leucaena leaf during incubation in ruinen fluid was much greater than for the purified mimosine. The substantial degradation observed when a buffer solution was substituted for rumen fluid was attributed to endogenous leaf enzymes. These enzyme systems were more efficient at degrading mimosine than were the microorganisms in the rumen liquor.

A model for permeation of mixed gases and vapors in glassy polymers

AbstractA model is discussed which explains reported complex effects of feed composition and pressure on component permeabilities in high‐pressure gas separators based on glassy polymer membranes. A special form of Fick's law which accounts for the fact that penetrants in glassy polymers sorb into and diffuse through two different molecular environments provides the basis for the analysis of gas mixture permeation. Potential deviations from the theory are discussed in terms of separable solubility‐and mobility‐related effects.

Preliminary Study of Cationic Copolymerization of α-Methylstyrene and Isobutyl Vinyl Ether. II

Abstract α-Methylstyrene (α-MS) and isobutyl vinyl ether (IBVE) were copolymerized by using the H2O/EtAlCl2 initiator system and CH2Cl2 and CH3Cl solvent in the temperature range from -30 to -90°C. As compared to homopolymerization of α-MS, both yields and molecular weights are reduced upon addition of small amounts of IBVE to the feed. The reactivity ratios were calculated by the method of Kelen and Tödös as well as the Fineman and Ross method, and the combined effect of change of solvent and temperature on reactivity ratios was determined. Effects of feed composition and temperature on the copolymer yield, composition, and number-average molecular weight M n were studied in detail. M n showed a novel exponential dependence on the IBVE concentration in the feed. The overall activation energies of molecular weight were determined from the Arrhenius plots for both homo-and copolymerization systems. Based on these and the yield data, a speculation is made regarding reaction mechanism for molecular weight control. NMR and DTA data are reported, which establish the random nature of the copolymers.

Ammoxidation of acrolein on catalyst of Fe–Bi–P mixed oxide system

AbstractAmmoxidation of acrolein (Al) on Fe2O3‐Bi2O3‐P2O5 (44.5:44.5:11.0 mol%) catalyst was studied in a fixed bed reactor. The main products were acrylonitrile (AN), CO2 and acetonitrile; and CO was negligibly small. The rate equations for Al conversion and product formation, together with their apparent activation energies, were obtained. The reaction rates are controlled by the chemical reaction rates at temperatures below 340°C, while the external film diffusion rates are the rate determining steps at temperatures above 380°C. Assuming the chemical reaction controlling region, the conversion rate of Al at 400°C is about 1000 times faster than that of propylene. From the effects of feed composition on selectivities, it is concluded that AN is produced according to Hadley's path.

Reaction kinetic studies: Catalytic dehydrogenation of sec‐butyl alcohol to methyl ethyl ketone

AbstractReaction kinetics for the catalytic dehydrogenation of sec‐butyl alcohol to methyl ethyl ketone has been investigated at atmospheric pressure and temperatures ranging from 650° to 750°F. in the presence of solid brass spheres, 1/8 in. in diameter. The nature of this catalyst permitted a direct evaluation of the surface involved in this reaction and allowed the definition of a surface‐feed ratio to be expressed as S/F in place of the conventional weightfeed ratio W/F commonly used in catalytic studies. Feed compositions ranged from secbutyl alcohol to mixtures containing high percentages of methyl ethyl ketone and hydrogen.In these studies mass transfer effects were found to be significant and, for a proper representation of conditiated at the catalyst surface, must be taken into account. The effect of feed compositions on the initial rates of reaction showed that the rate‐controlling step was the desorption of hydrogen involving a single‐site mechanism.In addition, the results of these studies have been used to produce values of height of reactor unit HRU which have been found to correlate with mass velocity and temperature. The HRU provides a simple means of calculating the depth of catalyst necessary to effect a designated conversion.