Distribution by Scientific Domains

Kinds of Tanks

  • cement tank
  • experimental tank
  • fibreglass tank
  • fuel tank
  • l tank
  • lc tank
  • plastic tank
  • rearing tank
  • rectangular tank
  • stirred tank
  • storage tank
  • water tank

  • Terms modified by Tanks

  • tank bioreactor
  • tank model
  • tank reactor
  • tank size
  • tank system

  • Selected Abstracts


    R.L. Smith
    First page of article [source]

    Inverted clast stratigraphy in an eolian archaeological environment

    Brenda J. Buck
    Understanding the geomorphic history of eolian basins is important in interpreting the archaeological record and human responses to past environments. One hundred forty soil profiles were excavated and described in southern New Mexico and West Texas. Seven major late Quaternary stratigraphic units were found: La Mesa, eolian Jornada (I, II), eolian Isaacks' Ranch, eolian Organ (I, II, and III), Historical Blowsand, and the playa deposits of Petts Tank and Lake Tank. Each unit represents a period of landscape instability, eolian erosion, and concurrent deposition, followed by landscape stability and soil formation. Eolian erosion can form local surficial lag deposits if materials larger than the competence of the wind are present. However, erosional processes alone cannot explain the presence of older clasts at the surface with intact, younger deposits underneath. We propose a combination of processes: deflation in eolian windows, followed by lateral movement of clasts over areas that have not been deflated. The effects of these processes on artifact stratigraphy and archaeological interpretations could be significant. © 2002 Wiley Periodicals, Inc. [source]

    2001 Fellows off the American Academy off Nurse Practitioners

    Article first published online: 24 MAY 200
    The Fellows of the American Academy of Nurse Practitioners (FAANP) Program has been established by the Academy to recognize nurse practitioners who have made outstanding contributions to health care practice, research, education or policy and to facilitate leadership in the nurse practitioner profession. Priority initiatives of FAANP are the development of leadership and mentorship programs for nurse practitioners. In addition, a yearly Think Tank is held to discuss the future of nurse practitioners and health care outside the confines of traditional thinking. The American Academy of Nurse Practitioners is pleased to present the 2001 Fellows. The 16 new Fellows were inducted at the Academy National Conference in Orlando on June 28, 2001. [source]

    Chariot: From Chariot to Tank, The Astounding Rise and Fall of the World's First War Machine , By Arthur Cotterell

    THE HISTORIAN, Issue 3 2007
    Antonio Santosuosso
    No abstract is available for this article. [source]

    Concept, Design and Manufacture of a Prototype Hydrogen Storage Tank Based on Sodium Alanate

    C. Na Ranong
    Abstract In the framework of the EC project STORHY (Hydrogen Storage for Automotive Applications), the prototype of a solid storage tank for hydrogen based on sodium alanate was developed. A storage tank containing 8,kg sodium alanate was designed and manufactured with the objective of fast refueling. To obtain the optimum design of the storage tank a simulation tool was developed and validated by experiments with a laboratory-scale tubular reactor. Application of the simulation tool to different storage concepts and geometries yielded the final design. The chosen concept is modular, enabling simple scale-up. This is the basis for the future development of fuel cell vehicle storage tanks containing 5,kg of hydrogen. [source]

    Simulation of Barium Sulfate Precipitation using CFD and FM-PDF Modeling in a Continuous Stirred Tank

    Z. Wang
    Abstract A mixing-precipitation model combining computational fluid dynamics (CFD), finite-mode PDF (probability density function) model, population balance and kinetic modeling has been proposed to simulate the barium sulfate precipitation process in a continuous stirred tank agitated by a Rushton turbine. The effect of various operating conditions such as impeller speed, feed concentration, feed position and mean residence time on the barium sulfate precipitation process is clearly demonstrated. It is shown that the mean crystal size increases by increasing the impeller speed and mean residence time. However, when the feed concentration is increased, the mean crystal size decreases. The predictions are in reasonable agreement with the experimental data in the literature. [source]

    Microstructural Investigation of Walking Parts of Military Tanks Coated with Arc Spraying

    U. Ozsarac
    The walking parts are the most important mechanical components in military tanks and other vehicles having palettes. The matrix phase of carrying wheels is Cu-based aluminum alloy. In this study, the microstructure of walking parts of military tanks was investigated deeply by optically and scanning electron microscopy. [source]

    Accumulation of Mycosporine-like Amino Acids in Asparagopsis armata Grown in Tanks with Fishpond Effluents of Gilthead Sea Bream, Sparus aurata

    Félix L. Figueroa
    Both the effects of total ammonium nitrogen (TAN) fluxes and the algal densities on MAA accumulation were investigated. MAAs increased with the TAN flux, but only until values lower than 100 ,M/h. Above this flux, the MAA content decreased, whereas algal yield increased. The content of individual MAAs was related to nitrogen (N) status, that is, shinorine percentage slightly decreased and palythine increased with increasing N fluxes. The decrease of MAAs at high flux of N (up to 100 ,M/h) is related to the decrease of water residence time and the decrease of the biofiltration efficiency. Under different TAN fluxes and algal densities, MAA content was negatively related to algal yield indicating that MAAs were accumulated only under a high ammonium-N availability. Thus, an energy allocation between growth (primary metabolism) and MAA accumulation (secondary metabolism) is regulated by the absorption capacity of inorganic N. In conclusion, A. armata, in addition to its high biofiltration capacity of nutrients, is a good source of MAAs as potential UV screen photoprotectors. [source]

    A Co-Simulation Approach for the 3D Dynamic Simulation of Vehicles Considering Sloshing in Cargo and Fuel Tanks

    Florian Fleissner
    The sloshing of liquids in cargo and fuel tanks mounted on vehicles can have a significant influence on the vehicle's driving dynamics and stability. To evaluate and optimize the quality of tank designs, we propose a co-simulation approach that consists of a coupled multibody system simulation for the vehicle and a Discrete Element Method and Smoothed Particle Hydrodynamics simulation for the sloshing cargo. This approach is beneficial especially for the simulation of fluid cargos, as Smoothed Particle Hydrodynamics does not require additional models to track and reconstruct free fluid surfaces. By means of dynamic 3D simulations of a double lane change maneuvers we compare the two different cargo models and demonstrate the viability of the co-simulation approach. (© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Suspension of Particles from the Bottom of Pipes and Stirred Tanks by Gassed and Ungassed Flows

    Rex B. Thorpe
    Abstract Widely accepted correlations and theoretical predictions for hydraulic conveying of solids in pipelines are compared with the literature on the suspension of particles in stirred tanks. Good agreement is found between the correlations and the theoretical predictions both within and between the two fields of study. The effect on the suspension velocity of introducing gas into the pipe and the stirred tank is remarkably similar. In both cases, the shear stress remains broadly unchanged when gas is added. Since the effect of the addition of gas on shear stress is quite well understood in both cases, this is a helpful result. Des corrélations et des prédictions théoriques largement acceptées pour le convoyage hydraulique de solides dans des conduites sont comparées à des données de la littérature scientifique sur la suspension des particules dans des réservoirs agités. Un bon accord est trouvé entre les corrélations et les prédictions théoriques dans et entre les deux champs d'étude. L'effet sur la vitesse de suspension de l'introduction de gaz dans la conduite et le réservoir agité est remarquablement similaire. Dans les deux cas, la contrainte de cisaillement reste largement inchangé lorsqu'il y a ajout de gaz. Ce résultat est utile car l'effet de l'ajout de gaz sur la contrainte de cisaillement est assez bien compris dans les deux cas. [source]

    Critical Impeller Speed for Suspending Solids in Aerated Agitation Tanks

    Yonggang Zhu
    Abstract Systematic measurements have been carried out in agitated gas-liquid-solids systems to determine the just off-bottom suspension speed. A variety of solids sizes, solids concentrations, impeller sizes and tank sizes are used. The difference between the just off-bottom suspension speeds with and without gas sparging does not show a linear relationship with the gassing rate and the relation is system-dependent. The relative just off-bottom suspension speed RJSS = Njsg / Njs is found to be dependent only on the just suspension aeration number Najs = Qg / NjsD3 and, for DT6 impellers, the relation is RJSS = 1 + mNanjs with the values of 2.6 and 0.7 for m and n, respectively. The relation is independent of the impeller size, solids size, solids loading and tank size, and can be used to scale up laboratory data to full-scale mixing vessels. Data from different studies support the present findings. Des mesures systématiques ont été effectuées dans des systèmes gaz-liquide-solides agités afin de déterminer la vitesse de suspension minimale au-dessus du fond du réservoir. Diverses tailles de solides, concentrations de solides, dimensions de turbines et dimensions du réservoir sont utilisées. La différence entre les vitesses de suspension minimale avec et sans aspersion de gaz ne suit pas une relation linéaire avec la vitesse de gazage et la relation est dépendante du système. On a trouvé que la vitesse relative de suspension minimale au-dessus du fond RJSS = Njsg / Njs est dépendante uniquement du nombre d'aération en suspension Najs = Qg / NjsD3 et que, pour les turbines DT6, la relation est RJSS = 1 + mNanjs, avec des valeurs pour m et n de 2,6 et 0,7, respectivement. La relation est dépendante de la dimension de la turbine, de la taille des solides, du chargement en solides et de la dimension du réservoir, et elle peut être utilisée pour mettre à l'échelle des données de laboratoire pour les mélangeurs en pleine grandeur. Des données provenant de diverses études appuient les présentes conclusions. [source]

    Thinking in Tanks: The Changing Ecology of Political Ideas

    First page of article [source]

    Inclusion of macroalgae meal (Macrocystis pyrifera) as feed ingredient for rainbow trout (Oncorhynchus mykiss): effect on flesh fatty acid composition

    Patricio Dantagnan
    Abstract The use of macroalgae as an additional component in animal feeding has been studied. However, information on how it could influence muscle composition of fish body is scarce. This study evaluates four diets with different macroalgae inclusion levels (0%, 1.5%, 3% and 6%) to test the effect on body fatty acid composition of rainbow trout. Tanks with a volume of 600 L were stocked with 60.6 ± 7.9 g fish at a density of 45 individuals tank,1 and fed for 124 days. At the end of the experiment there were not significant differences (P<0.05) in muscle proximate composition among fish fed the different treatments. However, it was determined that inclusion of 3% and 6% of macroalgae meal resulted in a significant increase (P<0.05) of polyunsaturated fatty acids (PUFAs) in muscle. In summary, macroalgae meal in rainbow trout diets do not enhance the quantity of protein and lipid contents at muscle level but an addition of 3,6% might contribute to increase the level of PUFAs, specially EPA, DHA and LIN. Thus, use of macroalgae meal might help to increase lipid quality content in the final product due the beneficial effects of PUFAs for human health. [source]

    Effect of settled sludge on dissolved ammonia concentration in tanks used to grow abalone (Haliotis midae L.) fed a formulated diet

    Rowan D Yearsley
    Abstract The relative contribution that solid waste or ,sludge', which accumulates at the bottom of abalone (Haliotis midae L.) tanks, makes to dissolved ammonia has not been established. Sludge was allowed to accumulate in 10 fully stocked abalone tanks, fed a formulated feed (Abfeed®; Marifeed, South Africa), for 24 days. Sludge was subsequently siphoned from five of these tanks. Total ammonia nitrogen (TAN) production and toxic, free ammonia nitrogen (FAN) were recorded in the tanks from which sludge was removed and compared with those from which sludge was not removed over the subsequent 50 h. Tanks with neither abalone nor sludge present were used as a control. The mean production of TAN (±standard deviation) was an average of 44% higher in tanks from which sludge was not removed compared with those from which it was, indicating that the sludge was a significant contributor to dissolved ammonia in the tanks. The toxic FAN concentrations were correspondingly higher in tanks with sludge present (2.3±0.3 ,L,1) compared with cleaned tanks (1.9±0.1 ,L,1). Our results indicate that regular removal of sludge from abalone tanks should significantly reduce the dissolved ammonia levels, thereby improving water quality in the culture environment. [source]

    Affect of Regime Changes on Nonstate Actors in Taiwan,Hong Kong Relations (1997,2010): Publicly and Privately Affiliated Think Tanks As Case Studies

    Simon Xuhui Shen
    The article reviews the roles of nonstate actors (NSAs) in general in Taiwan,Hong Kong relations during the administration of Hong Kong Special Administrative Region's first Chief Executive, Tung Chee-hwa (1997,2003), in order to explore the contributions and limitations of these agencies in constructing political spaces between Hong Kong and Taiwan. The first part of the article explains the reasons behind the short appearance of NSAs in Taiwan,Hong Kong relations after 1997. The second part, the case studies, looks at two selected NSAs: the Hong Kong Policy Research Institute in Hong Kong and the Friends of Hong Kong and Macau Association based in Taipei. The reasons for the setbacks they faced after 2003 and their possible roles following leadership changes in Hong Kong and Taiwan in the run-up to 2010 will be analyzed in the last section. [source]

    Storage Tanks at a Chemical Plant.

    Courtesy of Corbis Images (Chem. Eng.
    No abstract is available for this article. [source]

    Aeration of Large Size Tanks by a Surface Agitator

    R. Sardeing
    Abstract A new device has been developed in order to achieve urban or industrial wastewater biological treatment. It has been designed specially for lagoon applications to oxygenate and mix with the same apparatus. The goal is both to achieve a high gas flooding rate and to reach a maximal depth with the bubble plume. Mass transfer measurements have allowed us to choose the most appropriate geometry. Considering the application of the device and the possible use of low-pressure O2 produced on-site, the agitation system is located close to the liquid surface and is composed of a gas-inducing turbine. The role of propellers in addition to the gas-inducing turbine, as well as the use of baffles and a shell, have been experimentally studied. Numerical simulations (CFD) of the whole apparatus in single-phase flow have been used to study the influence of the stator part of the geometry. [source]

    Sources of Phenotypic and Genetic Variation for Seawater Growth in Five North American Atlantic Salmon, Salmo salar, Stocks

    William R. Wolters
    In 2003, pedigreed families were obtained from two St. John's River sources, Penobscot River, Gaspè, and landlocked salmon stocks. Eyed eggs were disinfected upon arrival, and incubated in separate hatching jars. Fry were transferred prior to first feeding into individual 0.1-m3 tanks receiving 8 L/min of oxygen-saturated freshwater from a recirculating biological filtration system. At approximately 30 d after the initiation of feeding, fish densities were equalized to 250 fish/tank, fed 5% of the tank's total biomass in 3,4 daily feedings. When the fish were approximately 40 g, approximately 30 fish from each family were pit tagged and stocked communally into three replicated 10-m3 smolt tanks. Approximately 1 mo prior to stocking into sea cages for performance evaluations, evaluations of serum chloride levels and gill Na+, K+ -ATPase activity were measured on subsamples from all stocks in freshwater and following seawater challenge. Smolts were stocked into sea cages in June 2005, harvested in February 2007, and evaluated for carcass weight, sex, and stage of sexual maturity. Data were analyzed by the mixed model ANOVA to determine the random effects of sire and dam (sire), and the fixed effects of sex, salmon stock, ploidy level, and replicate smolt tank on carcass weight with smolt weight as a covariate. Sire and dam variance components were significantly different from zero, and the fixed effects of salmon stock, sex × stock interaction, and smolt weight at stocking were significant (P < 0.05). There were no significant differences among sexes, replicate smolt tank, or ploidy level for carcass weight. Overall, St. John's River fish had the fastest growth with a carcass weight >4.1 kg compared with the slowest growth in landlocked fish at 1.7 kg. Grilsing was also highest in St. John's River fish (ca. 4,6%) and lowest in Penobscot River fish (0%). The sire heritability for carcass weight calculated from the sire variance component using the mixed model ANOVA or MTDFREML was 0.26 ± 0.14. Data were used to calculate breeding values on captive sibling adult brood fish, and a line selected for carcass weight was spawned in the fall of 2007, and eggs from these fish were released to industry. [source]

    Pilot Production of Hatchery-Reared Summer Flounder Paralichthys dentatus in a Marine Recirculating Aquaculture System: The Effects of Ration Level on Growth, Feed Conversion, and Survival

    Patrick M. Carroll
    Pilot-scale trials were conducted to evaluate growout performance of hatchery-reared summer flounder fingerlings in a state-of-the-art recirculating aquaculture system (RAS). The outdoor RAS consisted of four 4.57-m dia × 0.69-m deep (vol. =11.3 m3) covered, insulated tanks and associated water treatment components. Fingerlings (85.1 g mean initial weight) supplied by a commercial hatchery were stocked into two tanks at a density of 1,014 fish/tank (7.63 kg/m3). Fish were fed an extruded dry floating diet consisting of 50% protein and 12% lipid. The temperature was maintained between 20 C and 23 C and the salinity was 34 ppt. Under these conditions, growth, growth variation (CVwt), feed utilization, and survival of fish fed to 100% and 82% of a satiation rate were compared. Due to clear changes in growth patterns during the study, data was analyzed in three phases. During phase 1 (d 1,d 196), fish showed rapid growth, reaching a mean weight of 288 g ± 105 and 316 g ± 102, with a CVwt of 0.36 and 0.32 and FCR's of 1.38 and 1.36 in the subsatiation and satiation groups, respectively. During phase 2 (d 196,d 454), fish displayed slower growth reaching mean weights of 392 g ± 144 and 436 g ± 121, with a CVwt of 0.37 and 0.28, and increasing FCR's of 3.45 and 3.12 in the subsatiation and satiation groups, respectively. During phase 3 (d 454,d 614), fish showed little growth reaching mean weights of 399 g ± 153 and 440 g ± 129, with a CVwt of 0.38 and 0.29 in the subsatiation and satiation groups, respectively. Over the entire growout period (d 1,d 614), feed conversion ratios were 2.39 and 2.37 and survival was 75% and 81 % in the subsatiation and satiation treatments, respectively. The maximum biomass density reached during the study was 32.3 kg/m3. The satiation feed rate was superior to the 82% satiation rate, since it maximized growth rates, with no effect on FCR. The higher CVwt in the subsatiation group suggests increased competition for a restricted ration led to a slower growth with more growth variation. The decrease in growth in phases 2 and 3 was probably related to a high percentage of slower growing male fish in the population and the onset of sexual maturity. This study demonstrated that under commercial scale conditions, summer flounder can be successfully grown to a marketable size in a recirculating aquaculture system. Based on these results, it is recommended that a farmer feed at a satiation rate to minimize growout time. More research is needed to maintain high growth rates through marketable sizes through all-female production and/or inhibition of sexual maturity. [source]

    Effects of Amylopectin/Amylose Starch Ratio on Growth, Body Composition and Glycemic Response of Sunshine Bass Morone chrysops × M. saxatilis

    Steven Rawles
    Manipulation of the ratio of amylopectin (,-[1,4] and ,-[1,6] linked glucose) to amylose (,-[1,41 linked glucose) starches in the carbohydrate fraction of the diet has been used to improve carbohydrate and lipid metabolism in mammalian models. A 10-wk feeding trial was conducted to determine the effect of dietary amylopectin/amylose ratio on growth and composition of growth of advanced sunshine bass (Morone chrysops × M. saxatilis) fingerlings (60 g, initial weight). Fish were fed cold-pelleted, semipurified, isonitrogenous (35% crude protein), isocaloric (3.6 kcaVg protein), isolipidic (5%) diets containing 25% carbohydrate. The carbohydrate fraction of the diets was composed of either glucose, dextrin, 100% amylopectin/0% amylose, 70% amylopectin/30% amylose, or 30% amylopectin/70% amylose. Diets differing in ratios of amylopectin/amylose were achieved by adjusting the proportion of high-amylopectin (100% amylopectin) to high-amylose (70% amylose) corn starch. Diets were fed to fish in quadruplicate 76-L tanks (seven fish/tank) connected to a brackish water (5-7%v) recirculating culture system with biofiltration. Weight gain ranged from 195 to 236% of initial weight (60 g) and was significantly greater (P < 0.1) for fish fed diets containing 25% carbohydrate as dextrin or as 70% amylose and significantly lower in fish fed diets in which carbohydrate was composed of 30% amylose, 100% amylopectin, or glucose. Feed efficiency ranged from 0.52 to 0.61 and was higher in fish fed the diet containing the highest concentration of amylose and lower in fish fed the diet containing glucose. Hepatosomatic index was highest (2.71) in fish fed the diet containing glucose and lowest (1.401.45) in fish fed diets containing high-amylose cornstarch. Intraperitoneal fat ratio was distinctly lower in fish fed diets containing some amylose as compared to those fed diets without amylose. Liver lipid was significantly lower (4.8%) in fish fed the diet containing glucose and almost twice as high (7.3-8.9%) in fish fed the diets containing any starch. Glycogen content of the liver decreased from approximately 12% in fish fed the diet containing glucose to 5% in fish fed the diets containing amylose. Muscle proximate composition and ratio were unaffected by the dietary treatments. Fasting levels (15 h) of blood glucose in fish reared for 10 wk on the diet containing glucose were significantly elevated (5.5 mmol/L) when compared to fasting levels of those that had been reared on diets containing starch (3.4-1.1 mmol/L). Fish fed the diet containing glucose exhibited maximum blood concentrations (14.6 mmoVL) 4 h postprandial then rapidly declined to nearly fasting levels within 8 h postprandial. In contrast, maximum plasma glucose concentrations in fish fed diets containing starch were roughly half (6.8-8.1 mmol/L) those of fish fed the diet containing glucose. Blood glucose in fish fed diets containing dextrin or predominantly amylopectin starch remained elevated longer than that of fish fed diets containing glucose or predominantly amylose starch. Glycemic response appeared to decrease with increasing dietary amylose content. These data suggest that feeding diets in which a greater portion of the starch is amylose may be a useful strategy for improving carbohydrate use in sunshine bass. [source]

    Adsorption of Magnesium by Bottom Soils in Inland Brackish Water Shrimp Ponds in Alabama

    Harvey J. Pine
    Low-salinity (2.0,9.0 g/L) well waters used for inland culture of marine shrimp in Alabama are imbalanced with respect to ionic composition. Inputs of potassium (muriate of potash) and potassium-magnesium sulfate (Kmag®) fertilizers are used to correct these imbalances. Potassium is lost in overflow and intentional discharge, seepage, and through adsorption by bottom soils by exchangeable and non-exchangeable processes. This study was initiated to determine if bottom soils removed magnesium in the same manner as potassium. Laboratory soil,water mesocosms revealed that soils strongly adsorbed magnesium. The rate of adsorption tended to decline over time, indicating establishment of the equilibrium. Magnesium losses for the three soils ranged from 1405 to 1713 mg/tank (average = 1568 mg/tank). The cation exchange capacity (CEC) of the soils varied from 10.4 to 44.0 cmolc/kg (average = 24.6cmolc/kg). The decline in magnesium increased with higher soil CEC. In another trial, repeated exposures of soils to solutions of 40 mg Mg2+/L failed to saturate exchange sites, but rather maintained equilibrium with other base cations on soil adsorption sites. Dissolved sulfate resulting from additions of magnesium with magnesium sulfate heptahydrate (MgSO4·7H2O) was also monitored. Although difficulties of analysis occurred, sulfate was not adsorbed appreciably by the soils. [source]

    Effects of Diet and Water Source on the Nursery Production of Pacific White Shrimp Litopenaeus vannamei

    Clete A. Otoshi
    Penaeid shrimp reared in eutrophic pond water grow significantly faster than shrimp in clear well water, and this growth enhancement is especially pronounced in postlarval shrimp. The objective of this study was to determine if the nutritional benefits of pond water could supplement a lower protein feed for postlarval Pacific white shrimp Litopenaeus vannamei. Sixteen 230-L tanks were stocked with 10-d postlarvae at a density of 350 shrimp/tank. Four treatments (four replicates/treatment) were tested for 6 wk and consisted of: 1) shrimp grown in well water and fed a commercially available 45%-protein feed (W/45); 2) shrimp grown in pond water and fed the same 45%-protein feed (P/45); 3) shrimp grown in well water and fed a commercially available 52%-protein feed (W/ 52); and 4) shrimp grown in pond water and fed the same 52%-protein feed (P/52). At the end of the experiment. mean weight gain (± SE) for shrimp in pond water (1.85 ± 0.03 g) was significantly greater (P > 0.0001) than shrimp in well water (0.98 ± 0.10 g). Mean weight gain for shrimp fed the 52%-protein feed (1.56 ± 0.13 g) was significantly greater (P > 0.0001) than shrimp fed the 45%-protein feed (1.26 ± 0.20 g). In addition, there was a significant interaction effect between water source and feed (P > 0.0001). Mean weight gain for shrimp in the W/52 treatment (1.23 ± 0.04 g) was 68% greater than shrimp in the W/45 treatment (0.73 ± 0.03 g). However, mean weight gain for shrimp in the P/52 treatment (1.90 ± 0.03 g) was only 5% greater than shrimp in the P/45 treatment (1.80 ± 0.04 g). These results suggest that organically rich pond water provides postlarval shrimp with sufficient nutrients to compensate for nutritional deficiencies associated with a lower protein feed. [source]

    Simulation of compression refrigeration systems

    Jaime Sieres
    Abstract This study presents the main features of a software for simulating vapor compression refrigeration systems that are self designed by the user. A library of 10 different components is available: compressor, expansion device, condenser, evaporator, heat exchanger, flash tank, direct intercooler flash tank, indirect intercooler flash tank, mixer, and splitter. With these components and a library of different refrigerants many different refrigeration systems may be solved. By a user-friendly interface, the user can draw the system scheme by adding different components, connecting them and entering different input data. Results are presented in the form of tables and the cycle diagram of the system is drawn on the logP,h and T,s thermodynamic charts. © 2006 Wiley Periodicals, Inc. Comput Appl Eng Educ 14: 188,197, 2006; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20075 [source]

    Experience with model predictive control in the undergraduate laboratory

    Kenneth R. Muske
    Abstract A model predictive control experiment for an undergraduate senior laboratory course is outlined in this article. The process under study is a continuous stirred-tank heater and the control objective is to control the water temperature in the tank. A discrete, dynamic, physical model of this process is used in the controller. The model predictive control algorithm is a single-move, analytical controller that matches the model predicted temperature to a reference temperature trajectory at a single time in the future. A series of different control experiments using this algorithm are described and examples of each are presented. © 2005 Wiley Periodicals, Inc. Comput Appl Eng Educ 13: 40,47, 2005; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20028 [source]

    Sound production in two carapids (Carapus acus and C. mourlani) and through the sea cucumber tegument

    ACTA ZOOLOGICA, Issue 2 2006
    Eric Parmentier
    Abstract Parmentier, E., Fine, M., Vandewalle, P., Ducamp, J.-J. and Lagardère, J.-P. 2006. Sound production in two carapids (Carapus acus and C. mourlani) and throught the sea cucumber teguments. ,Acta Zoologica (Stockholm) 87: 113,119 Carapus acus and Carapus mourlani are able to live inside sea cucumbers and sea stars respectively. Unlike other carapids whose sounds have been recorded (C. boraborensis, C. homei and Encheliophis gracilis), these two species have a central constriction in their swimbladder and are unlikely to encounter heterospecific carapids within their hosts. We evoked sound production in Carapus acus and Carapus mourlani by adding several individuals to a tank with a single host and found that their sounds differ substantially from the sounds emitted by other carapids in pulse length, peak frequency and sharpness of tuning (Q3 dB). Unlike the other carapids, C. mourlani and C. acus produce shorter and less repetitive sounds and do not produce sounds when they enter their host. Since sounds produced within a sea cucumber have the potential to be heard by distant carapids and are typically recorded outside the sea cucumber, we examined the effect of the sea cucumber tegument on acoustic transmission. Attenuation by the tegument was negligible at the frequencies within carapid sounds. Therefore, carapids have the potential to call from the relative safety of a sea cucumber without sacrificing the distance over which their transmissions are heard. [source]

    Laboratory simulation of clast abrasion

    J. Lewin
    Abstract Experimental abrasion of river-bed materials has been widely undertaken, producing ,downstream' fining rates that generally are believed to be much less than those observed in the field. A conclusion commonly adopted has been that sorting processes are more effective than abrasion processes. A comparative evaluation of results from an abrasion tank and a tumbling barrel are presented, which show that abrasion patterns and rates differ according to the equipment used, clast size and shape, the clast charge (barrel) and water velocity and bed material (tank). Abrasion is a composite process, and the effects achieved appear to be dominated by percussion in the tank and grinding in the barrel. Breakage, crushing and sandblasting are not modelled effectively, nor are effects achieved on clasts when they form part of the bed. Comparisons are made with other equipment used, the very limited amount of direct field abrasion monitoring, and with the probable suite of processes that may occur under field conditions. Also reviewed are the problems that arise when laboratory weight-loss abrasion coefficients are used or converted into ones of size diminution, as usually derived from field observations of down-channel trends. It is concluded that field abrasion rates generally have been underestimated, as the processes involved are at best only selectively represented by the experimental equipment so far used, and because the results obtained experimentally are capable of misinterpretation when related to field trends. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Experimental investigation on the seismic response of a steel liquid storage tank equipped with floating roof by shaking table tests

    M. De Angelis
    Abstract In this paper, the effectiveness of the base isolation on steel storage tanks has been investigated through numerical models and then checked by shaking table tests on a reduced scale (1:14) model of a real steel tank, typically used in petrochemical plants. In the experimental campaign the floating roof has also been taken into account. The tests have been performed on the physical model both in fixed and isolated base configurations; in particular two alternative base isolation systems have been used: high-damping rubber bearings devices and sliding isolators with elasto-plastic dampers. Finally, a comparison between experimental and numerical results has also been performed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    An investigation of tuned liquid dampers equipped with damping screens under 2D excitation

    M. J. Tait
    Abstract This paper reports on the results of a study conducted on tanks partially filled with water, representing tuned liquid dampers (TLD), subjected to both 1D and 2D horizontal excitations. The sloshing response of the water in the tank is characterized by the free surface motion, the resulting base shear force, and evaluation of the energy dissipated by the sloshing water. A 1D non-linear flow model capable of simulating a TLD equipped with damping screens is employed to model a 2D TLD. Application of this particular model requires the assumption that the response is decoupled and can be treated as the summation of two independent 1D TLDs. Results from the non-linear flow model are compared with the 2D experimental shake table test results leading to a validation of the decoupled response assumption. This attractive decoupled response property allows square and rectangular tanks to be used as 2D TLDs, which can simultaneously reduce the dynamic response of a structure in two perpendicular modes of vibration. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Substrate choice of territorial male Topeka shiners (Notropis topeka) in the absence of sunfish (Lepomis sp.)

    C. C. Witte
    Abstract,,, Topeka shiners (Notropis topeka), an endangered minnow species, typically spawn on or around breeding Lepomis sunfish (Centrarchidae) nests. Why spawning Topeka shiners are attracted to these nests is unclear, but having the nesting sunfish provide shiner eggs with improved aeration, a lessening of siltation, and protection from egg predators are possibilities. We tested the substrate utilisation of Topeka shiners in outdoor tanks in the absence of sunfish to determine the shiner's fundamental choice. Shiners were provided with substrate patches of cleaned sand, small gravel, large gravel, and small cobble, and the bare floor of the tank. The substrate above which a male shiner established his territory was used as evidence of choice. A statistically significant choice for sand substrates was demonstrated. This fundamental choice might influence which sunfish nests Topeka shiners use, given that nest substrate characteristics differ both between sunfish species and within species by spawning site location. [source]

    Size-related differences in diel activity of two species of juvenile eel (Anguilla) in a laboratory stream

    G. J. Glova
    Abstract , The diel activity of three size groups (small=<100 mm; medium=100,199 mm; large=200,299 mm total length) of juvenile shortfinned ("shortfin") eels (Anguilla australis) and longfinned ("longfin") eels (A. dieffenbachii) was tested in a laboratory flow tank over a 48-h period during summer. All size groups of both species were nocturnally active, with the eels hiding in the substratum during the day and coming out on top of the cobbles from dusk to dawn, to feed. During the foraging period, the numbers and activity of all sizes of longfins visible were greater than those seen of shortfins, with the differences being more pronounced for small and medium eels. The activity of all eels consisted mostly of foraging by crawling, searching and probing for prey among the cobbles. Rate of activity increased with size of eel for both species. Small eels of either species did more swimming than eels of the larger sizes, whereas large eels were observed more frequently with only their head out of the substrate than were the smaller individuals. Feeding of small eels within the interstitial spaces of the streambed may explain their significantly lower activity on top of the substrate at night. The significantly lower rate of activity recorded for shortfins than longfins of all sizes may be due partly to their ability to feed within the interstices of the stream bed, and (or) longer time to recover from handling and habituate to the test environment., [source]