scholarly journals Development and Implementation of the Application APPMAR 1.0. A Toolbox for Management of Meteorological and Marine Data on Limited Information Regions

Author(s):  
German Rivillas-Ospina ◽  
Marianella Bolivar ◽  
Mauro Maza Chamorro ◽  
Gabriel Ruiz ◽  
Diego Casas ◽  
...  

This work presents an application called APPMAR 1.0 based on Python ® environment, built to perform the downloading, treatment and analysis of meteorological and marine information. This application is composed of two main modules: the first module allows the downloading of information from the database (NOAA - WW3); the second module uses the principles of statistical mathematics for the treatment of waves and wind. The importance of this simple application is based on the free and agile access to meteorological and marine information for a coastal project. The determination of representative conditions of sea states ultimately will govern the process of design of coastal and oceanic infrastructure. The analysis of historical time series of local waves and winds allows the evaluation of average regimes or operational design, the ultimate limit states or extreme design, and the storms or design by persistence. In spite that the former analysis is a common task for coastal engineers, the codes generated are seldom shared for public use. In summary, for operational purposes is useful to have a freeware that can assist in the data processing for decision making and forcing of the mathematical models that are part of the common practice of coastal, oceanic and offshore engineering. This application has been tested in the Caribbean area of Colombia where meteorological and marine information are scarce.

Author(s):  
João Paulo Boff Almeida ◽  
Renato Silva Nicoletti ◽  
Anderson Renato Vobornik Wolenski ◽  
Rafael Lemes Bezerra ◽  
Alex Sander Clemente de Souza ◽  
...  

<p>In the design of prestressed concrete structural elements, due to the fact that prestressing introduces actions in the structure, the limit states of crack formation service (SLS-F), decompression (SLS-D), and the ultimate limit state in the act of prestressing (ULS-ACT) are determinants in the dimensioning of the longitudinal reinforcement (Ap). In most cases, the longitudinal reinforcement required for the limit states is not exact, and the solution, if any, is within a range of values defined by the voltage limits of the SLS-F, SLS-D, and ULSACT. In this context, this paper aimed to verify, analytically, the limit states, service or ultimate, determinants in the calculation of Ap of unbonded post-tensioned beams. For this purpose, beams with material properties, environmental conditions, the width of the cross-section, and identical loads (except for their own weight) were analyzed, varying the height between 50 and 70 cm. It was found that the limits of tensile stress in the SLS-D and compression in the ULS-ACT for the lower edge, defined the intervals that were requested, simultaneously, by SLS-F, SLS-D, and ULS-ACT. For beams of lower height, the common range of solutions became more restricted and the ULS became decisive in the dimensioning of the longitudinal reinforcement, which did not occur for the higher beams.</p>


2018 ◽  
Vol 15 (1) ◽  
pp. 59
Author(s):  
NAZRUL AZMI AHMAD ZAMRI ◽  
CLOTILDA PETRUS ◽  
AZMI IBRAHIM ◽  
HANIZAH AB HAMID

The application of concrete filled steel tubes (CFSTs) as composite members has widely been used around the world and is becoming popular day by day for structural application especially in earthquake regions. This paper indicates that an experimental study was conducted to comprehend the behaviour of T-stub end plates connected to concrete filled thin-walled steel tube (CFTST) with different types of bolts and are subjected to pullout load. The bolts used are normal type bolt M20 grade 8.8 and Lindapter Hollo-bolt HB16 and HB20. A series of 10 mm thick T-stub end plates were fastened to 2 mm CFTST of 200 mm x 200 mm in cross-section. All of the specimens were subjected to monotonic pull-out load until failure. Based on test results, the Lidapter Hollo-bolts showed better performance compare to normal bolts. The highest ultimate limit load for T-stub end plate fasten with Lindapter Hollo-bolt is four times higher than with normal bolt although all end plates show similar behaviour and failure mode patterns. It can be concluded that T-stub end plate with Lindapter Hollo-bolt shows a better performance in the service limit and ultimate limit states according to the regulations in the design codes.


1906 ◽  
Vol 26 ◽  
pp. 32-45
Author(s):  
J. G. Milne
Keyword(s):  

During the excavations of Messrs. Hogarth Grenfell and Hunt for the Egypt Exploration Fund in the winter of 1895–6 on the site of Karanis (Kom Ushim) in the Fayum, a considerable number of clay-sealings were found, mainly in the cellars of the Roman houses. These were recently put in my hands for investigation and offer some interesting material.The sealings have evidently come from various kinds of articles: in many instances the clay is too much broken for any determination of the shape which it had taken to be possible; but among the better preserved pieces are examples from the mouths of bottles, some of which have been squeezed down into the neck like a cork, others placed over a linen covering, sometimes tied down with cord: others are from the flat sides of wooden boxes, often showing the marks of cord: others again from parcels of irregular shape, in some cases seemingly wrapped in papyrus. The common points of all are that they consist of lumps of Nile-mud, and that they have been impressed, while the clay was damp, with signets, which were presumably those of the merchants who forwarded the goods upon which the sealings were placed.


Author(s):  
Eric Brehm ◽  
Robert Hertle ◽  
Markus Wetzel

In common structural design, random variables, such as material strength or loads, are represented by fixed numbers defined in design codes. This is also referred to as deterministic design. Addressing the random character of these variables directly, the probabilistic design procedure allows the determination of the probability of exceeding a defined limit state. This probability is referred to as failure probability. From there, the structural reliability, representing the survival probability, can be determined. Structural reliability thus is a property of a structure or structural member, depending on the relevant limit states, failure modes and basic variables. This is the basis for the determination of partial safety factors which are, for sake of a simpler design, applied within deterministic design procedures. In addition to the basic variables in terms of material and loads, further basic variables representing the structural model have to be considered. These depend strongly on the experience of the design engineer and the level of detailing of the model. However, in the clear majority of cases [1] failure does not occur due to unexpectedly high or low values of loads or material strength. The most common reasons for failure are human errors in design and execution. This paper will provide practical examples of original designs affected by human error and will assess the impact on structural reliability.


2021 ◽  
pp. 51-56
Author(s):  
Yu. B. Sazonov ◽  
D. Yu. Ozherelkov ◽  
R. Sh. Latypov ◽  
E. E. Gorshkov

Possibility of determination of the fragments and articles made of different grades of steel aluminium and copper alloys and their affiliation to the common melt was examined via the methods of photoelectric spectral analysis based on composition of micro-impurities. Chemical elements with micro-impurities were revealed; they allow to determine affiliation of metal fragments to one melt. Ultimately possible deviations of micro-impurities within one melt were obtained. The technique allowing to establish affiliation of fragments to the common melt based on their elementary composition of micro-impurities with minimal amount of measurements was suggested based on the obtained results. The minimal geometric size of a sample available for analysis was determined; it allows to classify the examined fragments to one melt based on the results of investigation of expanded elementary composition of micro-impurities. Practical opportunities of this technique were displayed on the example of the alloys with different chemical composition.


2016 ◽  
Author(s):  
Michael Maraun ◽  
Moritz Heene

There has come to exist within the psychometric literature a generalized belief to the effect that a determination of the level of factorial invariance that holds over a set of k populations Δj, j = 1..s, is central to ascertaining whether or not the common factor random variables ξj, j = 1..s, are equivalent. In the current manuscript, a technical examination of this belief is undertaken. The chief conclusion of the work is that, as long as technical, statistical senses of random variable equivalence are adhered to, the belief is unfounded.


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