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Abstract

Stability is one of the most critical problems in the design of welded metal structures, since in many cases instability causes failure or collapse of the structures. The present study aims to show the minimum mass design procedure for welded steel box columns loaded by a compression force. The normal stresses and overall stability are calculated for pinned columns. The dimensions of the box columns are optimized by using constraints on global stability, local buckling of webs and flanges. Different design rules and standards are compared: Eurocode 3, Japan Railroad Association, American Petroleum Institute, and American Institute of Steel Construction. The calculations are made for different loadings, column length and steel grades. The yield stress varies between 235 and 690 MPa. Optimization is carried out using the generalized reduced gradient method in Excel solver. Cost calculations and comparisons show the most economical structure.

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Abstract  

8-Hydroxyquinoline (8-HOQ) is known as an important chelating agent for several metal ions. This compound is practically insoluble in water. For this reason, in this study its water soluble sulfate salt has been used for complexing uranyl ions and the stability constants of the complex have been determined. The Irving-Rosotti method computing the Calvin-Bjerrum pH-titration data, was applied. Finally, the stability constants of the complex formed between (8-HOQN-H)2SO4 and uranyl ions were found to be lgK1=8.25 and lgK2=4.15, the overall stability constant being {ie55-1}.

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Abstract  

The solubility products and thermodynamic functions for the praseodymium and ytterbium fluoride-water systems have been measured using different analytical techniques for comparison among the measured values as well as with values reported in literature. Although there is not much difference among our values obtained by potentiometric, conductometric and radiometric methods, the values for PrF3 disagree with at least two of the reported values. The effects of precipitant, aging of the precipitate and pH of the saturated solutions on the solubility product were studied and found to be significant. The standard enthalpy and free energy changes for the dissolution of both fluorides were found to be positive although the enthalpy for YbF3 is about twice as high as that for PrF3. The standard entropy change for PrF3 is negative, but that for YbF3 is positive. The overall stability constants for the mono- and difluoride complexes of both Pr and Yb have also been measured potentiometrically using a simplified approach.

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reported [ 19 , 20 ]. Table 1 Overall stability constants and thermodynamic functions for the reactions Cd 2 + + j L ⇌ CdL j 2 + (L = tripodal polyamine) in DMSO (NEt 4 ClO 4 0.1 mol dm −3 , 25 °C). The errors

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Journal of Thermal Analysis and Calorimetry
Authors: Teresa Sebio-Puñal, Salvador Naya, Jorge López-Beceiro, Javier Tarrío-Saavedra, and Ramón Artiaga

Pinus the overall stability was not improved by the extraction, but the shoulder at 250 °C disappeared. Thus, that shoulder represents some ethanol-extractives, different from those observed in Castannea, which do not affect the thermal stability of

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°C. This suggests that coordination of 1-Naph- N -Mecbm ( Fig. 1 ) to the metal ion enhances the overall stability of the complexes. Interestingly, the initial temperature of decomposition (IDT) has not been found to be dependent on the nature

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Journal of Behavioral Addictions
Authors: Bernadette Kun, Zsofia K. Takacs, Mara J. Richman, Mark D. Griffiths, and Zsolt Demetrovics

.053  Intellect/imagination 3,114 3 0.104 0.055; 0.153 4.135 <0.001   Overall Big Five 8,090 10 0.104 0.082; 0.125 9.350 <0.001  Overall Stability/Alpha 8,090 10 0.101 0.065; 0.137 5.492 <0.001  Overall Plasticity/Beta 7,462 8 0.061 0.030; 0.092 3.823 <0.001 Self

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