Amount Of Aeration Research Articles

The Study of Appropriate Strategy in Order to Avoid Economic losses Caused by the ICHthyophthirius Parasite on Ornamental Goldfish Species

This study aimed to provide the Appropriate Strategy in order to Avoid Economic losses Caused by the ICHthyophthirius Parasite on Ornamental Goldfish Species in the city of Shiraz in the four cardinal directions. In this study Pearl scale, Calico, Black Moor, Red Cap and Lionhead species, were examined and the prevalence of parasites in different conditions such as different temperatures, different turbidity, algal growth, feeding rate and etc. were reviewed. The main result is that management is the most important factor in this disease. The most resistant and most sensitive species are Calico and Pearl scale, respectively. In the absence of management prevalence is associated with increasing temperature and reaches its peak at 27 ° temperature. The proper management reduces the disease at high temperatures. Increased water turbidity, the amount of aeration, algal growth, water replacement rates are very important factors that make fish more susceptible to ICH disease. The results show that water temperature should be high for better and faster treatment of the disease and fish parasites more quickly reach the stage tomite. Goldfish lives at low temperatures, so it is better water temperature gradually raised from fish early life until goldfish reaches maturity to help fish adapt to high temperatures. This not only provides better management of ICH disease but also against other diseases and the disease can be treated quickly.

Effect of regrinding and pulp aeration on the flotation of chalcopyrite in chalcopyrite/pyrite mixtures

In flotation, regrinding is used to increase the liberation of value minerals, such as chalcopyrite, from gangue minerals. As a result of the significant decrease in particle size following regrinding, flotation efficiency is generally worst. In this study it is shown that the flotation recovery (and rate) of chalcopyrite in chalcopyrite–pyrite mineral mixtures, which is lower after regrinding, could be partially restored with aeration. The increase in Cp flotation upon aeration was attributed to the creation of a more favourable environment for xanthate adsorption and dixanthogen formation whereas the decrease in Cp flotation after prolonged aeration is due to its increased oxidation as a result of galvanic interactions with pyrite upon regrinding. The amount of aeration required for maximum flotation decreased monotonically with increasing feed grind particle size. To rationalize the observed chalcopyrite flotation trends, a simple model which involves competitive adsorption of xanthate and oxygen on chalcopyrite and pyrite surface sites and underpinning oxygen consumption and mineral oxidation effect is proposed.

Impact of loop seal structure on gas solid flow in a CFB system

In a circulating fluidized bed (CFB) boiler, loop seal is one of the most commonly used non-mechanical valves. When the solids are conveyed horizontally from the supply chamber to the recycle chamber through the horizontal section, the length of the horizontal section will cause much flow resistance, which not only influences the fan burden but also the pressure and mass balance between the furnace and the external loop.In this paper, a new structure loop seal with a slope passage connecting the supply and recycle chambers (named N-type) is described. The flow characteristic of quartz sand (Geldart-B particles) in the new loop seal was studied by comparison with the traditional loop seal (named U-type).The experimental data show that the passage design connecting the two chambers of a loop seal has an obvious effect on the gas solid flow not only in the loop seal, but also in other components in the whole loop. For the N-type loop seal, the minimum aeration rate required for the onset of solid flow is equal to the minimum fluidization velocity of the bed materials, much less than with the U-type loop seal. The solid recycling capability of the N-type loop seal is better than of U-type one at low aeration rate, but this status will be reversed at high aeration rate. A small amount of vertical aeration into the bottom of the standpipe can further improve the solid recycling capability of the N-type loop seal, by reducing the inter-particle friction and build up a higher pressure drop gradient in the standpipe. At the same time, less air bypassing upward into the cyclone through the standpipe is found for the N-type loop seal at high level of aeration rate, while, at the same condition the U-type suffers severe gas bypassing with a fluidized state in the standpipe. At last, the pressure drop of the new type loop seal is much less than the pressure drop of the traditional one with the same solid flow rate, which provides an advantage for reducing fan power and sustaining more solids in the boiler furnace.

소규모 간이상수도 시설에서 수온과 폭기량 변화에 따른 수중 라돈 제거 효율에 관한 연구

Radon, which is one of the radioactive elements in the natural world, exists in the atmosphere and water. When this element inflows into the human body, it carries the risks of developing lung cancer and stomach cancer. Therefore, in this study, an effective 10 L scaled reactor was produced to mitigate radon in water and the radon mitigation efficiency in water following the changes in water temperature and amount of aeration were evaluated. Based on this, the radon mitigation efficiency (SRRR; Specific radon removal rate) was derived per unit air volume. According to the study result, when water temperature increased from <TEX>$10^{\circ}C$</TEX> to <TEX>$16^{\circ}C$</TEX>, the SRRR value increased from 95 <TEX>$nCi/m^3{\cdot}L$</TEX> to 134.4 <TEX>$nCi/m^3{\cdot}L$</TEX>, and when the amount of aeration increased from 0.2 L/min to 1 L/min, the SRRR value decreased from 198.1 <TEX>$nCi/m^3{\cdot}L$</TEX> to 72.2 <TEX>$nCi/m^3{\cdot}L$</TEX>. Therefore, based on the experimental results, it is considered that it can be applied as a examination factor and objective indicator during the design of future radon-in-water mitigation systems.

Optimization method for the treatment of Tehran petroleum refinery wastewater using activated sludge contact stabilization process

ABSTRACTThis paper describes the results of side by side large scale testing of contact stabilization and extended aeration activated sludge processes on the petroleum refinery wastewater at Tehran (Iran) oil refinery by using continuous large scale experiments during the three month investigation period. The process optimization for performance evaluation was studied. Sampling results indicated that the contact stabilization process shows more effective performance than extended aeration process in removing chemical oxygen demand (COD) and biological oxygen demand (BOD), and also the mixed liquor volatile suspended solids were less in contact stabilization as compared to those in the extended aeration process. The excess sludge production was affected by the amount of sludge loading rate and aeration. The applied aeration to the mixed liquor and the sludge recycle rate were found to be critical parameters in the successful optimization of the contact stabilization process. The appropriate optimized opera...

Lipid production by Chlorella vulgaris after a shift from nutrient-rich to nitrogen starvation conditions

A two-stage process, composed of growth under nutrient-rich conditions followed by cultivation under nitrogen starvation and controlled conditions of phosphate, light intensity, aeration, and carbon sources was applied for lipid production by the green alga Chlorella vulgaris. Using conditions without addition of nitrogen, 2mg/L PO4-P, light intensity of 100μmol/m2/s and 0.25vvm of air, about 43% of dry cell weight accumulated as lipids after 12h, which equates to a lipid productivity of 77.8mg/L/d. In a medium containing 5mg/L NO3-N and 2mg/L PO4-P, and at a light intensity of 100μmol/m2/s and 0.25vvm of 2% CO2, about 53% of dry cell weight consisted of lipids after 24h, representing a lipid productivity of 77.1mg/L/d. The low amount of nutrients, moderate aeration and light intensity were helpful for increasing lipid productivity.

Mathematical modeling of aeration efficiency and dissolved oxygen provided by stepped cascade aeration

Mathematical modeling has been a vital tool in the field of environmental engineering. Various models have been developed to simulate the level of aeration efficiency (AE) provided by different aerating structures to raise levels of dissolved oxygen (DO) in streams; one of which is the stepped cascade structure. Three models developed by Gameson et al. WRL, and Nakasone, in addition to Qual2k, a computer program for stream modeling, have been used in this research; values of AEs obtained have been compared to those computed using DO measured from a built model at a WWTP. A stepped cascade structure was installed with different heights to aerate five flowrates with different levels of COD. An adjustment has been made to the Nakasone model to test the effect of pollutant load on the amount of aeration that could be reached. Values of AEs computed using the Gameson model were 30%, 39.5%, and 40% for cascade heights (H(d)) 45, 60, and 75 cm respectively for the five flowrates (q) that ranged from 21-66 m³/hr. Values of AEs from WRL model were 32.8%, 42%, and 43% consequently. Values of AEs from Nakasone model ranged from 4.6-7.5%, 6-10%, and 7.6-12% respectively. For the adjusted Nakasone model, values of AEs ranged from 3.2-4.9%, 3.3-5.3%, and 4.1-6.7% respectively. Finally, the AEs computed using the values of downstream DO generated by Qual2k ranged from 4-18%, 2-15%, and 2.5-5.1% correspondingly. Around 80% of the downstream DO values computed using the Nakasone and adjusted Nakasone model were closer to those measured in the field, thus more reliable in cascade design.

Positron emission particle tracking (PEPT) compared to particle image velocimetry (PIV) for studying the flow generated by a pitched-blade turbine in single phase and multi-phase systems

Abstract Positron emission particle tracking (PEPT) is a new technique allowing the quantitative study of flow phenomena in three dimensions in opaque systems that cannot be studied by techniques based on optical methods such as particle image velocimetry (PIV) or laser Doppler anemometry (LDA). It has previously been used for studying solid particle motion in various systems used in particulate processing. Here, for the first time, velocity measurements made using PEPT with a down-pumping pitched blade turbine (PBTD) are compared directly with those made by PIV in water in the same equipment. It is shown that excellent agreement is found between the two methods except just below the impeller in the discharge. However, this difference is attributed to the different type of data collected and the different way of ensemble-averaging in the two techniques. Similar results were found at higher agitator speeds with both the PBTD and an up-pumping PBT (PBTU) where a small amount of surface aeration occurred. Measurements in solid liquid systems with surface aeration at 0.5 wt% solids or higher were not possible with PIV, but excellent results were obtained with PEPT for both the PBTD and PBTU in a 5 wt% suspension. It is concluded that this calibration study shows that the PEPT technique can be used to obtain accurate velocity data throughout all of the complex three-dimensional flow field in a range of mechanically agitated, turbulent, multi-phase systems previously not amenable to quantitative analysis.

Photocatalytic degradation of wastewater from manufactured fiber by titanium dioxide suspensions in aqueous solution

This investigation concerned the use of titanium dioxide irradiated with UV light of 365 nm wavelength in a jacketed cylindrical glass reactor for the removal of organic pollutants from the final settling tank of wastewater from manufactured fiber production. The controlling factors of the feasibility studies included the amount of titanium dioxide, pH value, light intensity, and aeration on the decomposition. The results indicated that, with 0.25 g/L TiO 2, optimum decomposition could be attained. An excess amount of TiO 2 could block the light passage and lower the efficiency. The lower the pH value, the better the decomposition. The decomposition of organic pollutants was in proportion to the light intensity, while aeration was a decisive controlling factor, with dissolved organic carbon (DOC) removal efficiency from 30% without aeration to 75% with aeration.

Experimental Investigations of Free-Surface Aeration in the Developing Flow of Two-Dimensional Water Jets

Turbulent water jets discharging into the atmosphere are often characterized by a substantial amount of free-surface aeration. The effects can be detrimental or beneficial. In any case, the knowledge of the air entrainment mechanisms is essential for an optimum design. New experimental data are presented in the developing flow region of two-dimensional water jets discharging into air. The results indicate that the air diffusion takes place rapidly downstream of the nozzle and it is nearly independent of the momentum transfer process. Further, the distribution of air bubble frequency may be related to the air content distribution by a parabolic relationship.

圃場通気試験による機械耕うん土壌の特性評価

By an air permeability measurements, we tried to evaluate the difference of soil conditions in a field among the three tillage implements, a rotary tiller, a moldboard plow and a subsoiler.The results of our study are as follows.1. The soil aeration was effected by precipitation. The effect of tillage on the soil aeration was admonished for the amount of accumulated rainfall from 150mm to 200mm after tillage.2. The soil aeration indexed showed the best soil tillage aeration at the plowed plot. The indexed decreased quickly after tillage. It indicated that aeration affect didn't remain long period of time in the plowed plot. The moisture content of soil in plowed plot was wide range and tend to changes in lower moisture content range.3. The amount of soil aeration by rotary tillage were about 2/3 of that by plowing. The duration of tillage effect by the rotary tillage was approximately 1/2 shorter than that by the plowing.The rotary-tilled plot had the characteristics for the high moisture content of soil and bad drainage.4. The moisture contents at the rotary-tilled plot was changed by a subsoiler.5. The plowing improved the both of aeration and permeability of the soil and the subsoiling improved only the permeability by breaking up the deep layer.

海産小型ワムシＢｒａｃｈｉｏｎｕｓ ｒｏｔｕｎｄｉｆｏｒｍｉｓの高密度培養における好適通気法

In a high density culture of rotifer (beyond the levels of 103ind./ml), the amount of aeration needed to maintain an optimum dissolved oxygen (DO) level increases. In order to investigate the effect of aeration on the population growth of rotifer, a series of experiments were carried out. The S-type rotifer Brachionus rotundiformis was cultured at high density using 10l vessels under different aeration conditions. Air or oxygen gas was introduced into the culture media through two types of sparger which formed different sizes of bubbles, at aeration rates from 0.1 to 2.0vvm. The bubble-size from the two kinds of sparger were estimated from the value of KLa (volumetric oxygen transfer coefficient). When the aeration rate was high or the ceramic sparger that formed smaller bubbles was used, DO in the culture system remained at a high level. However, under these conditions, the growth of the rotifer population was seriously inhibited due to very high aeration rates and small bubbles, possibly as a result of foaming separation. When oxygen gas was introduced into the culture system, the density of rotifer was higher than that when air was introduced. Therefore, it is recommended to introduce high-purity oxygen gas for a high density culture to avoid any growth inhibition and to maintain optimum DO.

The relationship between feeding rate, paddlewheel aeration rate and expected dawn dissolved oxygen in intensive shrimp ponds

Determination of the proper level of supplemental aeration in intensive shrimp culture is critical for maintaining adequate concentrations of dissolved oxygen while minimizing equipment and operating costs. Little quantitative information is available on sizing the amount of aeration equipment to various levels of intensification. Results indicate that dawn dissolved oxygen (mg/liter) can be predicted based upon the amount of feed applied (kg/ha day) per unit aeration (hpday/ha). The amount of feed which can be applied with a given amount of supplemental aeration and a reasonable expectation that dawn dissolved oxygen will not be below a targeted concentration is expressed by the equation F A = 28·83 − (4·31 × DO) .

Internal oxygen transport inRumex species and its significance for respiration under hypoxic conditions

Rumex thyrsiflorus, Rumex crispus andRumex maritimus show a differential flood-tolerance in the river ecosystem in the Netherlands.R. thyrsiflorus occurs at high-elevated habitats and is flood-intolerant, the other two species occur at lower-elevated habitats and are flood-tolerant. We compared their respiratory activity under aerobic and anaerobic conditions in the root environment and quantified the internal gas transport. The results indicate that aerial oxygen can be used for root respiration in both aerobically and anaerobically grown plants. The amount of oxygen used via internal aeration increased with decreasing oxygen concentration in the root environment. Aerobically grown plants ofR. maritimus andR. crispus already showed a high internal aeration, but there was a significant increase in internal oxygen transport in anaerobic plants, where new, aerenchymatous roots had formed. This indicates the functional significance of new root formation for respiration in these species upon hypoxia. After two weeks of anaerobiosis, more than 50% of the total respiration of the roots of young plants ofR. maritumus and 40% of roots of young plants ofR. crispus was due to internal aeration at low oxygen concentrations in the root environment. InR. maritimus both young and old plants performed in this way, inR. crispus only young plants, whileR. thyrsiflorus showed some internal aeration, but this was hardly detectable. These differences can be explained on the basis of a different morphology and concomitant diffusive resistance of both root and shoot system. In experiments with different submergence levels of the shoot, the amount of internal aeration was positively correlated to the total leaf area protruding above the water surface inR. maritimus. This indicates a functional significance of the petiole and leaf elongation response upon total submergence of this species.

Maintaining dense-phase standpipe downflow

The varied combinations of inlet orientation, fluidized milieu, catalyst rheology, aeration provisions, relative value areas, and line diameters have clouded appreciation of the phenomenology involved in attaining maximum static pressures at the base of industrial standpipes operating at bulk solids downflow velocities in excess of 5 ft/s. Several relationships have been derived to determine the amount of aeration to be injected between any two locations along the standpipe height. Bulk solids of low viscosity and low surface tension are least likely to lead to vapor binding or a cholic standpipe. The mechanism leading to bubble build-up and its relation to common draw-off arrangements is outlined.

Heritable and temperature-induced meristic variation in the medaka, Oryzias latipes.

Eggs from 25 parental pairs were reared at sustained temperatures from 20C to 34C, or were changed from 20C to 30C or vice versa al various developmental stages. Crowding, mechanical shoes, container type, amount of aeration, and malachite green prophylaxis did not alter numbers of vertebrae, and pectoral or dorsal rays; nor did these numbers vary between eggs laid on different days by the same parents. Numbers of anal and caudal rays were significantly different between sibling egg batches, and were decreased by crowded rearing conditions. Mechanical shock increased anal ray counts. Caudal rays were sometimes decreased by lack of aeration. Response of vertebrae to different sustained temperatures was U-shaped in nine groups, with nadirs varying from 24C to 32C; in two groups, vertebrae were progressively fewer at higher temperatures. Pectoral ray counts usually were progressively lower at higher temperatures. Dorsal ray counts of most formed arched curves. In all series, heritable variation at one temperature roughly equalled phenotypic variability between temperatures. Inherited differences in response patterns of different meristic series are largely independent of each other, and of mortality and of hatching time. Temperature breaks produced an overcompensation in vertebrae if applied early, or a paradoxical reaction if applied late.

Biotechnology report. Solid state fermentations.

AbstractA unique method is described by which large yields of secondary metabolites arc produced on solid substrates. The process involves the use of moist substrates which are continuously agitated in appropriate fermentation equipment. The amount of agitation, aeration, and moisture can be varied. Extremely high yields of secondary metabolites such as ochratoxin and aflatoxin were obtained using Aspergillus and Penicillium species. The process prevents sporulation of the fungus and because of the nature of the solid substrate makes recovery of the product easier than in conventional liquid media. The substrates include rice, corn, wheat, and other cereals.

Selective inhibition of enzyme synthesis under conditions of respiratory inhibition.

When Neurospora mycelium is transferred from a medium containing sucrose to one containing acetate as sole source of carbon, a preferential synthesis of many Krebs cycle, glyoxylate cycle, and associated enzymes occurs. Respiration was inhibited during preferential enzyme synthesis in the following ways. (i) The amount of aeration (shaking) was reduced, (ii) cyanide was added to the culture, (iii) the carbon source, acetate, was removed, (iv) a mutant strain was starved of its Krebs cycle intermediates, and (v) respiration was inhibited by mutation. The effect of this respiratory inhibition on the synthesis of a number of enzymes was measured. It was found that the synthesis of nicotinamide adenine dinucleotide (NAD)-linked glutamate dehydrogenase and phosphoenolpyruvate carboxykinase was significantly less inhibited under conditions of respiratory inhibition than was the synthesis of Krebs cycle, glyoxylate cycle, and most other cell proteins synthesized during the adaptation period. This differential inhibition of enzyme synthesis was almost certainly not due to differential repression by regulatory metabolic end product effectors. Inhibition of mitochondrial respiration under these conditions most likely results in a limitation of the energy supply of the cell. Thus, it is suggested that the inhibition of synthesis of most proteins after inhibition of mitochondrial respiration results from a lack of energy in a utilizable form. Possible reasons to account for the relative insensitivity of NAD-linked glutamate dehydrogenase and phosphoenolpyruvate carboxykinase to inhibition under these conditions are discussed.

Quantitative Determination of Hydroxymethylfurfural in Sherries and Grape Concentrate

A rapid colorimetric method has been adapted to the determination of hydroxymethylfurfural (HMF) in wines and grape concentrates. The method depends on the reaction of p-aminodimethylaniline with hydroxymethylfurfural to form a soluble red product. Preparation of the reagent and method of application are presented. HMF formation in sherry making is affected by sugar content, baking time, and amount of aeration. HMF content in various California and Spanish sherry wines is reviewed.

CLEAR LIQUID MEDIUMS FOR THE "AEROBIC" CULTIVATION OF ANAEROBES

Anaerobic organisms are often overlooked in clinical and biologic laboratories because of the lack of a simple anaerobic medium which can be used just as any aerobic broth without the use of anaerobe jars or other special equipment or technics. It is well known that most clear liquid mediums when heated to drive out the air will be anaerobic for a short time. Whether this period is long enough to allow germination of the spores or growth of the anaerobes present depends on the composition of the medium, the amount of aeration while inoculating and several other factors. For most purposes the period of anaerobiosis obtainable in this manner is not sufficient. To avoid the use of mechanical devices such as the marble seal, special tubes or layers of oil or petrolatum, various substances have been added in attempts to prolong the anaerobiosis and still have a clear liquid medium