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  • 1
    Electronic Resource
    Electronic Resource
    Berkeley, Calif. : Berkeley Electronic Press (now: De Gruyter)
    International journal of emerging electric power systems 8.2007, 3, art5 
    ISSN: 1553-779X
    Source: Berkeley Electronic Press Academic Journals
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: This paper presents the steady-state and transient behavior of a single-phase self-excited induction generator (SEIG) using a three-phase machine with one shunt and one series excitation capacitors for resistive and inductive loads. The generation scheme consists of one three-phase delta connected induction machine and two capacitors - one connected in parallel with one winding and the other in series with a single-phase load. The dynamic model of the system has been developed as a hybrid model considering the stator phase currents in abc reference frame and the rotor currents in stationary d-q axes reference frame as state variables. The simulated and experimental results are presented for different dynamic conditions such as initiation of self-excitation, load perturbation and short-circuit. The simulated results of the steady-state analysis have been compared with the transient and experimental results and a close agreement between them indicates the accuracy and effectiveness of the approach.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two double-cross populations were used to evaluate the efficiency of independent, alternate, and simultaneous selection practiced from the F2 to F8 for resistance to anthracnose and angular leaf spot of common bean (Phaseolus vulgaris L.). Seven resistant and high-yielding lines were selected from each of the four environments used during this study. These lines and the seven parents involved in two populations were evaluated in an 8 × 8 lattice design with three replications in two cropping seasons. Pathogen inoculum was used to create the three test environments: anthracnose alone, angular leaf spot alone, and anthracnose and angular leaf spot together. All entries were also evaluated in a fourth, disease-free environment. Selection for resistance to anthracnose and angular leaf spot was effective in both populations. Mean disease scores of all selected lines for anthracnose were lower than that of angular leaf spot irrespective of selection environment. Among the three stress environments, yields were higher in the anthracnose environment. However, lines selected alternately for anthracnose and angular leaf spot were usually higher yielding, and the highest yielding line in both populations originated from this selection environment. The mean yield of selected lines was higher and the highest yielding line originated from the population involving a parent (G 1805) belonging to the Mexican highland race ‘Jalisco’. Positive association existed between seed yield of protected and pathogen-inoculated environments. No association was found between resistance to anthracnose and angular leaf spot.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Plant breeding 107 (1991), S. 0 
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Additive genetic variance in large-seeded common beans (Phaseolus vulgaris L.), mostly of Andean South American origin, was higher than nonadditive variance for all traits. Heritability was 0.43 ± 0.19 for yield, 0.49 ± 0.20 for pods/m2, 0.63 ± 0.21 for seeds/m2, 0.76 ± 0.23 for 100-seed weight, and 0.55 ± 0.22 for days to maturity. Expected gain from selection (expressed in percentage of the population mean) was 9.2 for yield, 12.8 for pods/m2, 21.0 for seeds/m2, 17.6 for 100-seed weight, and 4.6 for days to maturity.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1439-0523
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Two populations of common bean, Phaseolus vulgaris L., were used to make three independent location-specific selections at Palmira, Quilichao, and Popayán, Colombia. Also, three across-location selections were made by alternating generations between Palmira and Popayan, between Quilichao and Popayán, and among Palmira, Quilichao, and Popayán. The seven highest yielding lines selected from each environment and population along with 14 parents and two checks were evaluated for seed yield, seed weight, maturity, and reaction to an-thracnose, angular leaf spot, and common bacterial blight. Mean squares due to evaluation and selection environments, selected lines, and their interactions were significant for all traits. Mean yields of selected lines were higher than the mean of parents in both populations. Among location-specific selections, lines yielded higher at their respective selection site. Moreover, selections made at Popayán were higher yielding than those made at Quilichao or Palmira when tested across locations and years. Use of Popayán, a relatively wetter and cooler site, either alone or in combination with other locations resulted in higher yield, higher seed weight, and higher resistance to anthracnose. On the average, location-specific selections were lower yielding than the across-location selections. Among across-location selections, those selected between Palmira and Popayán were the highest yielding in both populations. Selections at Palmira and across all three locations resulted in greater stability.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1572-8838
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract LaNiO3 electrodes were prepared, in the form of thin films on platinum by the methods of spray pyrolysis and sequential coating of mixed metal nitrate solutions followed by thermal decomposition. The films were adherent and of p-type semiconducting. Cyclic voltammetric studies indicated the formation of a quasireversible surface redox couple, Ni(iii)/Ni(ii), on these films before the onset of oxygen evolution in 1 m KOH. The anodic Tafel slopes were ∼40 and ∼65 mV decade−1, on the sprayed LaNiO3 film and on the film obtained by a layer method, respectively. The reaction order with respect to OH− was found to be 2.2 on the sprayed oxide film and 1.2 on the layer film. The sprayed oxide film was found to be electrocatalytically more active. It is suggested that the oxygen evolution reaction proceeds on both the film electrodes via the formation of the physisorbed H2O2 as an intermediate in the rate determining step.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 3 (1990), S. 208-212 
    ISSN: 1572-8773
    Keywords: Hg2+ toxicity ; Nostoc calcicola ; Electrolyte leakage ; NO3 − uptake ; Nitrate reductase ; Metal interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effect of mercury (Hg2+) in the absence and presence of methylmercury (CH3Hg+), cadmium (Cd2+), copper (Cu2+), nickel (Ni2+) and calcium (Ca2+) on Nostoc calcicola Bréb. has been studied in terms of electrolyte leakage, NO3 − uptake and in vivo nitrate reductase (NR) activity to discover any possible correlation among such parameters under Hg2+ stress. Leakage of electrolytes from Hg2+-treated cyanobacterial cells was directly proportional to Hg2+ concentrations and exposure time. In comparison to NO3 − uptake, an about 60-fold slower rate of NR activity was observed in the untreated cultures, the former being five times more Hg2+-sensitive. A non-competitive synergistic interaction of Hg2+ with CH3Hg+ or Cd2+ and antagonistic with that of Ni2+ or Ca2+ has been observed for both the processes of NO3 − utilization. The antagonistic interaction of Cu2+ with Hg2+ in terms of NO3 − uptake and synergistic with respect to NR activity, has been attributed to the dual bonding preference of Cu2+ for cellular ligands. These findings suggest that (a) a statistically significant correlation exists among such parameters; (b) Hg2+ predominantly attacks the cyanobacterial cell membrane; (c) Hg2+ inhibits NO3 − utilization; (d) the presence of other cations increases or decreases the inhibitory actions of Hg2+.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 5 (1992), S. 229-234 
    ISSN: 1572-8773
    Keywords: biofilm ; cell aging ; cyanobacterium foam ; immobilization ; Nostoc calcicola ; spheres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Methyl mercury uptake in free cells and different immobilizates of the cyanobacteriumNostoc calcicola has been examined. The general growth of the immobilized cyanobacterial cells could be negatively correlated with methyl mercury uptake. Alginate spheres proved most efficient in terms of uptake rate (0.48 nmol mg protein−1 min−1, 10 min) and total bioaccumulation (10.71 nmol mg protein−1, 1 h) with a bioconcentration factor of 3.3×103. Alginate biofilms showed a faster methyl mercury accumulation rate (0.83 nmol mg protein−1 min−1, 10 min) with a saturation of 10.28 nmol mg protein−1 reached within only 30 min (bioconcentration factor, 3.1×103). Foam preparations with a slow initial uptake approximated biofilms but were characterized by a lower bioconcentration factor (2.8×103). Free cells, in comparison, maintained the initial slow rate of uptake (0.62 nmol mg protein−1 min−1, 10 min), saturating at 30 min (8.81 nmol mg protein−1), and the resultant lowest bioconcentration factor (2.7×103). Cell ageing (30 days) brought a drastic reduction (3-fold) in organomercury uptake by free cells while alginate spheres maintained the same potential. Foam preparations of the same age showed a significant improvement in methyl mercury uptake followed by only a marginal decline in alginate biofilms. Data are discussed in the light of the physiological efficiency and longevity of immobilized cells.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1420-9071
    Keywords: Insulin-like growth factor ; insulin-like growth factor binding protein ; RIA ; methods ; fetal serum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Solvent extraction of serum and other biological fluids at an acidic pH is a convenient method to remove the insulin-like growth factor binding proteins (IGFBPs); however, an incomplete removal of IGFBPs can occur and this can potentially interfere with the radioimmunoassay of insulin-like growth factors (IGFs). This study compared the removal of IGFBPs from normal adult rat serum and 5-day old neonatal rat serum by acid-gel filtration, and three solvent extraction methods, i.e., acid-ethanol (AE), acid-cryo-ethanol (ACE) and formic acid-acetone (FAA) treatments by western ligand blotting and slot-blotting analysis. In adult rat serum all three extraction methods removed nearly 75% of total IGFBPs present. For the neonatal serum, AE and FAA were very inefficient in eliminating the IGFBPs, while ACE was somewhat better, as it removed nearly 30% of IGFBPs. Ligand blots of extracted samples showed that IGFBPs of lower size range, 24 to 32 kDa (IGFBP-4, IGFBPs-1 and-2), were resistant to solvent extraction. Acid-gel filtration, in contrast, eliminated 〉95% of IGF-binding components in both sera. Determination of IGF-I concentrations in samples after gel filtration and extraction methods revealed lower IGF-I values in neonatal serum in acid extracted samples. These data caution against using solvent extractions for IGFBP removal in fetal/neonatal serum.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 4 (1991), S. 192-196 
    ISSN: 1572-8773
    Keywords: Cu uptake ; Starvations ; Recovery ; ATP ; Nostoc calcicola
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The kinetics of Cu uptake in nutritionally starved cells of the diazotrophic cyanobacteriumNostoc calcicola Bréb. have been compared with those in cells recovering from starvation. Unstarved cyanobacterial cells assimilated 97.0 nmol Cu mg−1 protein within 1 h when incubated in medium containing 40 μM Cu. Uptake was markedly inhibited in carbon-starved cells and, to a lesser extent, in cells starved of nitrogen or sulphur. The intracellular concentrations of protein and photopigments were markedly lower in cells starved of carbon, nitrogen, sulphur or phosphorus, whilst that of carbohydrate was lower in cells starved of carbon, sulphur or phosphorus, but almost doubled in cells starved of nitrogen. The ability to assimilate Cu was partially restored in cells after 72 h of recovery from phosphorus or sulphur deprivation, but showed little improvement during recovery from carbon or nitrogen starvation. A possible role of phosphorus in regulating Cu transport and accumulation is discussed.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    BioMetals 5 (1992), S. 149-156 
    ISSN: 1572-8773
    Keywords: Hg2+ toxicity ; cyanobacterium ; Nostoc calcicola ; growth ; photopigments ; nucleic acids ; photosynthesis ; membrane integrity ; nutrient uptake ; enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Toxicological responses of the filamentous N2-fixing cyanobacteriumNostoc calcicola Bréb. towards Hg2+ were studied to enumerate the decisive lethal events. In low-dose, long-term experiments (0.05–0.25 μm Hg2+, 10 days), photoautotrophic growth was severely inhibited with concurrent loss of photosynthetic pigments (phycocyanin〉chlorophyll α〉carotenoids) and nucleic acids. The termination of growth after a day 4 exposure to 0.25 μm Hg2+ has been attributed to the complete inhibition ofin vivo photosynthetic activity in the cyanobacterium (O2 evolution〉14CO2 incorporation). The elevated Hg2+ concentrations irreversibly damaged the cell membrance as observed under light microscopy, and as indicated by the leakage of intracellular electrolytes and phycocyanin. In high-dose, short-term experiments (0.5–20.0 μm Hg2+, up to 6 h), thein vivo activities of selected enzymes (glutamine synthetase 〉 nitrate reductase 〉 nitrogenase) were less inhibited by Hg2+ than the uptake of nutrient ions (NH 4 + 〉NO 3 − 〉PO 4 3− ).
    Type of Medium: Electronic Resource
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