Overview of Calculation Methods of Structural Time-Dependent Reliability

Under the action of natural erosion, the strength, durability and other safety performance of structures and elements gradually decrease with time, which has a great impact. To solve the above problem, a series of time-dependent reliability analysis methods were proposed. Based on different structural performance functions, this paper analyzes and discusses different time-dependent reliability theories, including outcrossing-based reliability method, Monte Carlo simulation method, extremum method and other new methods proposed in recent years, which provides reference for later research.

Analysis of Calculation Methods Currently Practised at V4 Agricultural Holdings

This paper assesses calculation methods in the Visegrad 4 countries (Czech Republic, Hungary, Poland and Slovakia) and, based thereon, recommends and considers activity-based costing (ABC) in the agricultural sector, while evaluating manager knowledge of ABC as an appropriate alternative to outdated, “conventional” methods of calculating costs that are used in practice. It was found that a majority of agricultural holdings in the V4 are currently using conventional cost calculation methods and the most frequent reason for their failure to incorporate ABC is low awareness among managers. Farms and agricultural holdings that have introduced ABC and utilise it to assign their costs evaluate its benefits highly positively, in particular, ABC’s more accurate identification of costs, mainly overheads; more effective cost management and the accuracy of price estimates. From this analysis and assessment, introduction of ABC is recommended for companies in order to obtain the different benefits associated with the method. Successfully implementing ABC leads to a number of advantages, especially in the inevitable decision-making agricultural holdings face about high overhead costs. From the information obtained, managers at agricultural holdings have little information, in most cases, about ABC as an appropriate alternative to the outdated “conventional” cost estimate methods practised today. It is therefore important to work on raising managers' awareness of new approaches to costing by publishing scientific articles with specific examples from practice, pointing out the advantage of the ABC method, especially with high overheads, which are almost the rule in agricultural holdings.

Soil Acidification, Mineral Neoformation and Heavy Metal Contamination Driven by Weathering of Sulphide Wastes in a Ramsar Wetland

Past waste disposal practices have left large volumes of sulphidic material stockpiled in a Ramsar wetland site on the Atlantic coast of southwestern Spain, leading to severe land degradation. With the aim of addressing this legacy issue, soil core samples were collected along two transects extending from the abandoned stockpiles to the adjacent marshland and subjected to XRD, SEM-EDS, ICP-OES and ICP-MS analyses. Sulphide oxidation has been shown to be a major driver of acid generation and metal leaching into the environment. The marsh soil receiving acid discharges from the sulphide wastes contains elevated levels (in mg kg−1) of Pb (up to 9838), As (up to 1538), Zn (up to 1486), Cu (up to 705), Sb (up to 225) and Tl (up to 13), which are retained both in relatively insoluble secondary minerals (mainly metal sulphates and oxides) and in easily soluble hydrated salts that serve as a transitory pool of acidity and available metals. By using a number of enrichment calculation methods that relate the metal concentrations in soil and their baseline concentrations and regulatory thresholds, there is enough evidence to conclude that these pollutants may pose an unacceptable risk to human and ecological receptors.

Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs

The scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in what range of support stiffness the corner concentrations become important in the calculation of the punching resistance. For shear caps with high flexibility (α1 ≤ 0.5), the concentration of internal forces in the corners does not occur. The authors compare the numerical results obtained from the calculation methods and indicate the correlations, which can be useful guidance for structural designers. In the case of large shear caps, the simplified MC2010 method gives a significantly lower value of the effective control perimeter length compared to more accurate methods. This paper is intended to provide scientists, civil engineers, and designers with guidelines on which factors influence punching shear load capacity of the slab–column connections with shear caps.