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Retention Capacity (retention + capacity)
Kinds of Retention Capacity Selected AbstractsShrinkage of initially very wet soil blocks, cores and clods from a range of European Andosol horizonsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2007F. Bartoli Summary In advanced stages of volcanic ash soil formation, when more clay is formed, soil porosity values and soil water retention capacities are large and the soils show pronounced shrinkage on drying. Soil shrinkage is a key issue in volcanic soil environments because it often occurs irreversibly when topsoils dry out after changes from permanent grassland or forest to agriculture. European Andosols have developed in a wide range of climatic conditions, leading to a wide range in intensity of both weathering and organo-mineral interactions. The question arises as to whether these differences affect their shrinkage properties. We aimed to identify common physically based shrinkage laws which could be derived from soil structure, the analysis of soil constituents, the selected sampling size and the drying procedure. We found that the final volumetric shrinkage of the initially field-wet (56,86% of total porosity) or capillary-wet (87,100% of total porosity) undisturbed soil samples was negatively related to initial bulk density and positively related to initial capillary porosity (volumetric soil water content of soil cores after capillary rise). These relationships were linear for the soil clods of 3,8 cm3, with final shrinkage ranging from 21.2 to 52.2%. For soil blocks of 240 cm3 and soil cores of 28.6 cm3 we found polynomial and exponential relationships, respectively, with thresholds separating shrinkage and nearly non-shrinkage domains, and larger shrinkage values for the soil cores than for the soil blocks. For a given sample size, shrinkage was more pronounced in the most weathered and most porous Andosol horizons, rich in Al-humus, than in the less weathered and less porous Andosol horizons, poor in Al-humus. The Bw horizons, being more weathered and more porous, shrank more than the Ah horizons. We showed that the structural approach combining drying kinetics under vacuum, soil water analysis and mercury porosimetry is useful for relating water loss and shrinkage to soil structure and its dynamics. We also found that the more shrinkage that occurred in the Andosol horizon, the more pronounced was its irreversible mechanical change. [source] Sorption of copper by a highly mineralized peat in batch and packed-bed systemsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2 2010Marta Izquierdo Abstract BACKGROUND: The performance of peat for copper sorption was investigated in batch and fixed-bed experiments. The effect of pH was evaluated in batch experiments and the experimental data were fitted to an equilibrium model including pH dependence. Hydrodynamic axial dispersion was estimated by tracing experiments using LiCl as a tracer. Six fixed-bed experiments were carried out at copper concentrations between 1 and 60 mg dm,3 and the adsorption isotherm in dynamic mode was obtained. A mass transport model including convection,dispersion and sorption processes was applied for breakthrough curve modelling. RESULTS: Maximum uptake capacities in batch mode were 22.0, 36.4, and 43.7 mg g,1 for pH values of 4.0, 5.0, and 6.0, respectively. Uptake capacities in continuous flow systems varied from 36.5 to 43.4 mg g,1 for copper concentrations between 1 and 60 mg dm,3. Dynamic and batch isotherms showed different shapes but a similar maximum uptake capacity. Sorbent regeneration was successfully performed with HCl. A potential relationship between dispersion coefficient and velocity was obtained with dispersion coefficients between 5.00 × 10,8 and 2.95 × 10,6 m2 s,1 for water velocities ranging between 0.56 × 10,4 and 5.03 × 10,4 m s,1. The mass transport model predicted both the breakpoints and the shape of the breakthrough curves. CONCLUSIONS: High retention capacities indicate that peat can be used as an effective sorbent for the treatment of wastewater containing copper ions. Copyright © 2009 Society of Chemical Industry [source] Regulating the mobility of Cd, Cu and Pb in an acid soil with amendments of phosphogypsum, sugar foam, and phosphoric rockEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2006F. Garrido Summary When acid soil has been contaminated by metals as a result of industrial discharges, accidental spills, or acid mine drainage it may be desirable to retain the metals in the soil rather than allow them to leach away. We have investigated the potential of phosphogypsum (PG), sugar foam (SF), and phosphoric rock (PR) to regulate the availability and mobility of Pb, Cd and Cu. We have also identified changes in attenuation during incubation for 1 year and the effect of aging on metal speciation in amended soils. We studied miscible displacement in columns of undisturbed soil previously treated with solutions of the amendments and soluble metals and, subsequently, single and sequential chemical metal extractions. All amendments increased the soil's metal retention capacity. This, in turn, increased the amount of metal extractable by diethylenetriaminepentaacetic acid (DTPA). However, over time the amounts of DTPA-extractable metal decreased, particularly for Cu and Pb. Both Cu and Cd were held preferentially within the acetic acid-extractable fraction (operationally defined exchangeable fraction , EX fraction), whereas Pb was associated mainly with the hydroxylammonium-extractable fraction (operationally defined bound to Fe and Al hydroxides , OX fraction). Both Pb and Cu in the oxide and organic fractions increased in the PG- and SF-treated soils. In general, the distribution of metal did not change in the PR-treated columns after the incubation. Finally, scanning electron microscopy in back-scattered electron mode (SEM,BSE) showed the formation of Al-hydroxy polymers which provides the soils with additional cation sorption capacity. In the PG- and PR-treated columns, P and S were associated with these formations. The three metals were associated with the Al polymers, probably through direct coordination or the formation of ternary complexes with the inorganic ligands phosphate and sulphate. [source] Immobilization of the heavy metals Cd, Cu and Pb in an acid soil amended with gypsum- and lime-rich industrial by-productsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 1 2004V. Illera Summary In situ stabilization of heavy metals in contaminated soils by the addition of various types of soil amendment is an attractive technique for remediation. We investigated the potential of three industrial by-products (phosphogypsum, red gypsum and dolomitic residue) for boosting the heavy metal sorption capacity of an acid soil (patents pending, Spanish applications no 200201704 and 200201375) by using sorption isotherm experiments. The three by-products were found substantially to increase the retention of lead, cadmium and copper on the solid components of the soil. The increase in lead retention of the soil horizons upon the addition of both phosphogypsum and red gypsum was dominated by the formation of anglesite minerals. The dolomitic residue increased the metal retention capacity of the soil horizons through the precipitation of laurionite-type minerals as well as cadmium and copper hydroxy-chlorides. In addition to the batch sorption study, we used scanning electron microscopy to investigate the metal sorption processes in the soil by the effect of the treatments. Lead was frequently found to be linked to the edge charges of kaolinite minerals. The three metals were found to be associated with organic matter in the Ap horizon treated with the three by-products. Finally, the three metals were found to be associated with undissolved dolomitic residue particles. [source] Balances of phosphorus and nitrogen in carp pondsFISHERIES MANAGEMENT & ECOLOGY, Issue 1-2 2000R. Knösche The impact of carp pond effluents on natural waters was investigated in the German federal states of Brandenburg, Saxony and Bavaria, and in Hungary. Data from 38 ponds (size = 0.25,122 ha) were available for the calculation of inlet,outlet differences. An average difference of 0.51 kg phosphorus (P) ha,1 year,1 was obtained. This means that every hectare of pond surface releases 510 g P less than it receives from the incoming water. This result was independent of the amount of fish harvested (, 1500 ha,1 year,1). The average retention of P (P-balance) was 5.71 kg P ha,1 year,1. Phosphorus retention increased with increasing intensity of production. Nitrogen (N) retention increased with production intensity from 78.5 kg ha,1 year,1 in German standard ponds to >,290 kg N ha,1 year,1in pig-cum-fish ponds in Hungary. A predominantly mineralized sludge suspension is released during harvesting at loads below 1% of the retention capacity of the pond. Under usual pond management regimes, the sludge load during harvesting ranged from 50 to 200 L ha,1, equivalent to 0.3,9.3 g dry matter ha,1. The present study suggests that ponds are not a burden on the environment. By contrast, these water bodies improve water quality. Therefore, pressures to reduce the intensity of pond production cannot be justified on the basis of supposed impacts on water quality. However, even if loads during harvesting are low compared with the retention capacity of the pond, more effort should be carried out to reduce the pollution of streams by pond outlets downstream. This can be done by limiting pond drainage to periods when the suspended material has settled or by short-term sedimentation of the sludge in a settling pond downstream of the rearing facility. [source] Response of secondary production by macroinvertebrates to large wood addition in three Michigan streamsFRESHWATER BIOLOGY, Issue 8 2009SALLY A. ENTREKIN Summary 1.,We measured responses in macroinvertebrate secondary production after large wood additions to three forested headwater streams in the Upper Peninsula of Michigan. These streams had fine-grained sediments and low retention capacity due to low amounts of in-channel wood from a legacy of past logging. We predicted that wood addition would increase macroinvertebrate secondary production by increasing exposed coarse substrate and retention of organic matter. 2.,Large wood (25 logs) was added haphazardly to a 100-m reach in each stream, and a 100-m upstream reach served as control; each reach was sampled monthly, 1 year before and 2 years after wood addition (i.e. BACI design). Macroinvertebrate secondary production was measured 1 year after wood addition in two habitat types: inorganic sediments of the main channel and debris accumulations of leaf litter and small wood. 3.,Overall macroinvertebrate production did not change significantly because each stream responded differently to wood addition. Production increased by 22% in the main-channel of one stream, and showed insignificant changes in the other two streams compared to values before wood addition. Changes in main-channel macroinvertebrate production were related to small changes in substrate composition, which probably affected habitat and periphyton abundance. Macroinvertebrate production was much greater in debris accumulations than in the main-channel, indicating the potential for increased retention of leaf litter to increase overall macroinvertebrate production, especially in autumn. 4.,Surrounding land use, substrate composition, temperature and method of log placement are variables that interact to influence the response of stream biota to wood additions. In most studies, wood additions occur in altered catchments, are rarely monitored, and secondary production is not a common metric. Our results suggest that the time required for measurable changes in geomorphology, organic matter retention, or invertebrate production is likely to take years to achieve, so monitoring should span more than 5 years, and ecosystem metrics, such as macroinvertebrate secondary production, should be incorporated into restoration monitoring programs. [source] Carbon emission and sequestration by agricultural land use: a model study for EuropeGLOBAL CHANGE BIOLOGY, Issue 6 2002L. M. Vleeshouwers Abstract A model was developed to calculate carbon fluxes from agricultural soils. The model includes the effects of crop (species, yield and rotation), climate (temperature, rainfall and evapotranspiration) and soil (carbon content and water retention capacity) on the carbon budget of agricultural land. The changes in quality of crop residues and organic material as a result of changes in CO2 concentration and changed management were not considered in this model. The model was parameterized for several arable crops and grassland. Data from agricultural, meteorological, soil, and land use databases were input to the model, and the model was used to evaluate the effects of different carbon dioxide mitigation measures on soil organic carbon in agricultural areas in Europe. Average carbon fluxes under the business as usual scenario in the 2008,2012 commitment period were estimated at 0.52 tC ha,1 y,1 in grassland and ,0.84 tC ha,1 y,1 in arable land. Conversion of arable land to grassland yielded a flux of 1.44 tC ha,1 y,1. Farm management related activities aiming at carbon sequestration ranged from 0.15 tC ha,1 y,1 for the incorporating of straw to 1.50 tC ha,1 y,1 for the application of farmyard manure. Reduced tillage yields a positive flux of 0.25 tC ha,1 y,1. The indirect effect associated with climate was an order of magnitude lower. A temperature rise of 1 °C resulted in a ,0.05 tC ha,1 y,1 change whereas the rising CO2 concentrations gave a 0.01 tC ha,1 y,1 change. Estimates are rendered on a 0.5 × 0.5° grid for the commitment period 2008,2012. The study reveals considerable regional differences in the effectiveness of carbon dioxide abatement measures, resulting from the interaction between crop, soil and climate. Besides, there are substantial differences between the spatial patterns of carbon fluxes that result from different measures. [source] Oxidation of biologically produced elemental sulfur under neutrophilic conditions,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2010Marc Fortuny Abstract BACKGROUND: Previous research on a biotrickling filter for the removal of high loads of H2S showed that accumulation of elemental sulfur (S0) when dealing with high H2S concentrations could lead to reactor clogging. Since S0 can also serve as substrate for sulfur-oxidising bacteria, this study investigates the biological oxidation of S0 as a remediation strategy. RESULTS: Results indicated that biological oxidation of S0 inside a clogged biotrickling filter occurred at a comparable rate to those reported for stirred tank reactors. When biologically produced dried and powdered S0 was manually added as a substrate in stirred tank reactor experiments, significantly lower S0 oxidation rates were found compared to those for biological S0 freshly produced in situ. It was speculated that either the powdered S0 particle size or the surface properties hindered S0 bioavailability even in a well-stirred environment. Respirometric experiments with the same powdered S0 and acetone-dissolved S0 confirmed that biological oxidation of S0 was basically limited by the solid S0 bioavailability. CONCLUSIONS: Therefore, results showed that S0 oxidation basically depends on S0 bioavailability and that Sulfate volumetric production rates as high as 3.48 mmol SO42, h,1 L,1 can be achieved inside a clogged biotrickling filter probably due to the high biomass retention capacity. Overall, the results indicate that biological oxidation of S0 can be considered a suitable strategy for unclogging bioreactors clogged with S0. Copyright © 2010 Society of Chemical Industry [source] BAKING PERFORMANCE OF 1BL/1RS SOFT RED WINTER WHEATSJOURNAL OF FOOD QUALITY, Issue 2 2001WILLIAM E. BARBEAU ABSTRACT Baking performance of nine 1BL/1RS soft red winter wheat (SRWW) lines and six non-1BL/1RS lines was assessed during two crop years, 1995,96 and 1996,97, and at two locations, Blacksburg and Warsaw, Virginia. The 1BL/1RS flours produced cookies with significantly smaller diameters than non-1BL/1RS flours (p , 0.0026) across both growing years and locations. There was a highly significant negative correlation (r =,0.709) between cookie spread and alkaline water retention capacity (AWRC) of SRWW flours. Overall, there was no significant difference (p = 0.2552) in biscuit volume of 1BL/1RS and non-1BL/1RS flours. There were no significant differences in cake volumes of 1BL/1RS and non-1BL/1RS flours when data from both years and locations were combined, p = 0.0710; or when Blacksburg and Warsaw locations were considered separately, p = 0.2009 and 0.1882, respectively. Finally, there were no significant differences in the texture of cakes made from 1BL/1RS and non-1BL/1RS flours regardless of growing year or location. These results suggest that the 1BL/1RS translocation significantly reduces the cookie spread of SRWW flours but has no significant impact on biscuit or cake quality. [source] Extraction and Application of Dietary Fiber and Cellulose from Pineapple CoresJOURNAL OF FOOD SCIENCE, Issue 4 2002T. Prakongpan Pineapple core dietary fiber (PDF) was obtained by alcoholic extraction; pineapple core cellulose (PC) was a product of alkali extraction with a bleaching process. Total dietary fiber content of PDF and PC was 99.8% and 95.2% (dry basis), respectively, and their water activity was 0.25. PC contained 91.2% cellulose with a pH value of 4.0, while that of PDF was 6.2. The fiber product with large particle size gave higher values than the product with smaller particles for pH, water and oil retention capacity, settling volume and emulsifying activity. Both had rough, pitted surfaces and presented showed good functions in cake-type doughnuts, golden layer cake and beef burgers. [source] Nitrogen Sources and Sinks Within the Middle Rio Grande, New Mexico,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 4 2007Gretchen P. Oelsner Abstract:, Relationships between discharge, land use, and nitrogen sources and sinks were developed using 5 years of synoptic sampling along a 300 km reach of the Rio Grande in central New Mexico. Average river discharge was higher during 2001 and 2005 "wet years" (15 m3/s) than during the drought years of 2002-04 "dry years" (8.9 m3/s), but there were no differences in nitrogen loading from wastewater treatment plants (WWTPs) which were the largest and most consistent source of nitrogen to the river (1,330 kg/day). Average total dissolved nitrogen (TDN) concentrations remained elevated for 180 km downstream of the Albuquerque WWTP averaging 1.2 mg/l in wet years and 0.52 mg/l in dry years. Possible explanations for the constant elevated TDN concentrations downstream of the major point source include reduced nitrogen retention capacity, minimal contact with riparian or channel vegetation, large suspended sediment loads, and low algal biomass. Somewhat surprisingly, agricultural return flows had lower average nitrogen concentrations than river water originally diverted to agriculture in both wet (0.81 mg/l) and dry years (0.19 mg/l), indicating that the agricultural system is a sink for nitrogen. Lower average nitrogen concentrations in the river during the dry years can be explained by the input of agricultural returns which comprise the majority of river flow in dry years. [source] Habitat restriction in Mammillaria pectinifera, a threatened endemic Mexican cactusJOURNAL OF VEGETATION SCIENCE, Issue 6 2003José Alejandro Zavala-Hurtado Dávila-Aranda et al. (1993) Abstract. This study deals with the habitat restriction of Mammillaria pectinifera, a threatened cactus species, confined to a few low density localities of the Tehuacán valley in tropical Mexico. We analysed the patterns of presence/absence of M. pectinifera in relation to the presence/absence of 48 other plant species, and the variation of environmental factors in 120 sampling plots. A Principal Components Analysis revealed a clear segregation between plots with and without individuals of M. pectinifera. A classification analysis resulted in four groups: two with low prevalence and two with high prevalence of M. pectinifera. Paired comparisons between plots with and without M. pectinifera allowed the characterization of its patterns of occurrence related to the variation of environmental factors. M. pectinifera was found on deep alkaline soils with relatively high surface stoniness and high water retention capacity, showing low species richness compared with plots where it was absent. The limited distribution of M. pectinifera in the Tehuacán Valley seems to be related to particular requirements of this species, being restricted to certain suitable habitat patches. Nevertheless, it is likely that other aspects, such as poor dispersal and establishment abilities, or biotic interactions could be associated with the observed patterns. [source] Influence of nests of leaf-cutting ants on plant species diversity in road verges of northern PatagoniaJOURNAL OF VEGETATION SCIENCE, Issue 3 2000A.G. Farji-Brener Correa (1969,1998) Abstract. It has been suggested that ant nests are the most frequent small-scale disturbance that affect vegetation patterns. However, their effects on plant diversity are little studied. We document effects of nests of the leaf-cutting ant Acromyrmex lobicornis on physical-chemical soil properties and their influence on plant diversity near road verges in a desert steppe in NW Patagonia, Argentina. We analysed nest soils and controls for nitrogen, phosphorus, organic matter, moisture retention capacity and texture. We also analysed the vegetation on 42 nests (30 active and 12 abandoned or without life) and 42 areas without nests. Soil around nests had a greater nutrient content and capacity to retain moisture than control soils, which is mainly due to the presence of organic waste that the ants deposit on the soil surface. We found no association between the occurrence of nests and specific groups of plants, but plant diversity was higher at nest-sites than at nearby non-nest sites. This increased diversity , which is also found on abandoned nests , is mainly due to the occurrence of a larger number of native and exotic plant species on nest-sites that are uncommon elsewhere in the study area. The most abundant plant species showed similar cover values at nest and non-nest sites. This suggests that changes in diversity are associated to edaphic changes caused by nests rather than by changes in competitive balance caused by dominant species exclusion. We propose that the nests of Acromyrmex lobicornis, through increasing the availability of resources, generate favourable microsites that can function both as ,refuges' for less frequent native species, and as,stepping stones' for less frequent exotic plant species. [source] Effects of field reorganisation on the spatial variability of runoff and erosion rates in vineyards of Northeastern SpainLAND DEGRADATION AND DEVELOPMENT, Issue 1 2010M. C. Ramos Abstract This study analyses the spatial variability of runoff and erosion rates in vineyards due to mechanisation works. Runoff samples were collected at three positions in two plots after 33 erosive events in three years (2001, 2003, 2004) with different rainfall patterns. Three replications were considered at each position. Soil properties were evaluated in order to analyse its relationship with runoff and erosion rates. Runoff and erosion rates were, on average, higher in the levelled plot (HD), ranging between 8·4 and 34·3 per cent, than in the non-levelled plot (LD) ranging between 8·2 and 24·1 per cent. Mean sediment concentration in runoff ranged between 6 and 8,g,L,1 in the HD plot and about 4·6,g,L,1 in the LD plot, but with high differences within the plot. In the HD plot, runoff-rainfall rates were significantly higher (at 95 per cent level) in the upper part of the slope and decreased along the slope, while in the LD plot, differences in runoff rates were not significant and similar to those observed in the less disturbed areas of the HD plot. The higher susceptibility to soil sealing in areas where the original topsoil was removed conditioned runoff rates. In the lower part of the HD plot runoff rates were, on average, 20 per cent lower than in the upper part of the slope. In those positions runoff rates up to 79 per cent were recorded. Organic matter content and water retention capacity at different potentials are the soil characteristics related to the differences on runoff and erosion rates in the resulting soils. Copyright © 2009 John Wiley & Sons, Ltd. [source] Preparation of Water-Absorbing Polyacrylonitrile Nanofibrous MembraneMACROMOLECULAR RAPID COMMUNICATIONS, Issue 2 2006Haiqing Liu Abstract Summary: Hydrophilic acrylic nanofibers were prepared from alkaline hydrolysis of hydrophobic polyacrylonitrile (PAN) nanofibers. Water contact angle, pore volume, and liquid retention capacity of PAN nanofibrous membranes were measured to determine their dependence on hydrolysis parameters such as base concentration, temperature, and time. Vertical water retention capacity of hydrolyzed PAN nanofibrous membrane could reach as large as 200 times of that of original membrane. Fiber twinning in post-hydrolyzed PAN nanofibrous membrane. [source] Quality effect of wheat-rye (1R) translocation in ,Pavon 76'PLANT BREEDING, Issue 4 2005W. Kim Abstract A growing interest exists in using wheat for producing both hard and soft wheat products. It would be desirable if 1RS translocations in hard wheat could produce flour suitable for soft wheat products. The objective of this study was to test the effects of centric translocations of chromosome 1 from different rye sources for end-use quality. The quality influences of the 1RS and 1RL translocations and 1R substitutions from different rye sources were studied in a set of hard spring wheat ,Pavon 76'(CIMMYT) lines in three environments in Georgia. The protein concentration of the 1RL translocations was the highest while the 1RS translocations showed no difference in protein concentration compared with that of controls. The 1RS translocations increased alkaline water retention capacity while the 1RL translocations reduced it. T1DSAE1RL was preferred for soft wheat products over other genotypes. [source] Synthesis of the hydrophobic,hydrophilic macroporous poly divinylbenzene/poly(sodium acrylate) IPN resin and adsorption performance for berberinePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2009Guqing Xiao Abstract The macroporous polydivinylbenzene/poly(methyl acrylate) interpenetrating polymer network (PDVB/PMA IPN) was prepared by the sequential suspension polymerization method, and was modified to be hydrophobic,hydrophilic macroporous polydivinylbenzene/poly (sodium acrylate) IPN (PDVB/PNaA IPN) by converting the PMA to PNaA under the condition of base. The effects of different mass ratio of the two networks and different cross-linking degree of the second network on the pore structure and adsorption capacity of PDVB/PNaA IPN resin were studied. The PDVB/PNaA IPN resin whose adsorption quantity is the biggest was chosen to study further. The pore structure, the weak acid exchange capacity, the water retention capacity, and the swelling ability of PDVB/PNaA IPN resin were measured. The study focused on the adsorption isotherms of berberine at different temperatures. Isosteric adsorption enthalpy, adsorption Gibbs free energies can be calculated according to thermodynamic functions. The results show that the saturated adsorption quantity of berberine is up to 109.4,mg,ml,1 (wet resin) by the way of dynamic adsorption and desorption experiment. The resin could be reused by the mixture with 0.5% sodium chloride and 80% ethanol. On the one hand the hydrophobic PDVB in the PDVB/PNaA IPN resin has the ability of adsorption using ,,, interaction, and on the other hand the hydrophilic PNaA in the PDVB/PNaA IPN resin has the ability of adsorption using ion exchange interaction. An important conclusion can be drawn that the PDVB/PNaA IPN resin has a promising application prospect in extracting and separating quaternary ammonium type alkaloids such as berberine. Copyright © 2009 John Wiley & Sons, Ltd. [source] Growth performance of weaning red abalone (Haliotis rufescens) fed with Macrocystis pyrifera plantlets and Porphyra columbina compared with a formulated dietAQUACULTURE RESEARCH, Issue 15 2009Jorge Hernández Abstract A feeding experiment was carried out to evaluate two natural diets versus a formulated feed on the performance of weaning red abalone Haliotis rufescens. Four treatment diets were then investigated: a formulated diet; plantlets from culture Macrocystis pyrifera, Porphyra columbina from natural beds; and a mixed diet consisting of a blend of fresh P. columbina together with the formulated diet. This study was performed in a shallow aquaculture system with a horizontal water flow. After 90 days, significant differences were observed between treatments. The highest growth was obtained with Porphyra (3.3 mm month,1), followed by the mixed diet (2.6 mm month,1), then Macrocystis (2.1 mm month,1) and lastly the formulated diet (1.4 mm month,1). Moreover, after the diets were tested for stability and remnant nutrients after a 12-h water immersion, a positive trend appeared to be related to the protein/energy (P:E). It is concluded that fronds of P. columbina resulted in the best diet for weaning H. rufescens under horizontal water flow systems, even if apparently the water stability of the formulated diet had a negative impact on abalone performance, particularly due to a poor nutrient retention capacity. Therefore, formulated diets should be improved before being recommended for weaning red abalone. [source] Investigation on SO2 emission from 410t/h circulating fluidized bed boiler burning petroleum coke and coalASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Lun-Bo Duan Abstract Effects of operation parameters including bed temperature, Ca/S molar ratio, excess air coefficient, fly ash recirculation rate and limestone microstructure on SO2 emission were investigated on a 410t/h circulating fluidized bed (CFB) boiler burning petroleum coke and coal. Results show that for different fuels, SO2 emission is correspondingly related to the sulfur content in it under the same operation conditions. With increasing bed temperature, SO2 concentration in the flue gas reduces first and then increases. There is an optimal desulfurization temperature. For burning bituminous coal (BC) only or 70% BC + 30% petroleum coke (PC), the optimal desulfurization temperature is about 850 °C, while it is about 850,870 °C for burning 50% anthracite (AN) + 50% PC. SO2 emission decreases with the increase in Ca/S ratio, excess air coefficient and fly ash recirculation rate. Microstructure of limestone has distinct effects on their SO2 retention capacity, and bigger specific surface area and higher specific pore volume lead to stronger SO2 capture activities. The optimal temperature, Ca/S ratio and excess air coefficient for different fuels are recommended for industrial application. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | |||||||||||||||||||