The paper presents results of tests on the effect of the addition of fly ash (FA) in the amounts of 0%, 20%, and 30% by weight of cement on the interfacial microcracks in concrete composites subjected to dynamic loads. The analyses were carried out based on the results of the microstructural tests using a scanning electron microscope (SEM). The average width of the microcracks (Wc) in the interfacial transition zone (ITZ) of coarse aggregate with cement matrix was evaluated. During the studies beneficial effect of the addition of FA on reduction of the size of Wc in the ITZ of concrete composites under dynamic loading were observed. Based on obtained test results, it was found that using the 20% FA additive causes favorable changes in the microstructure of mature concrete. In this composite, the average value of Wc was lower by more than 40% compared to the result obtained for the reference concrete. In contrast, concrete containing 30% FA additive had greater microcracks in the ITZ area by over 60% compared to the material without additive. In all analyzed composites, an increase in the Wc value by almost 70% to over 110% in the case of occurrence of dynamic loads was also observed. This was the most evident in the case of concrete with a higher content of FA.

The Beneficial Effect of the Addition of Fly Ash on Reduction of the Size of Microcracks in the ITZ of Concrete Composites under Dynamic Loading

A novel specific requirements for materials used in reinforced concrete composites subjected to dynamic loads

The purpose of the present paper is to assess groundwater contamination by ammonium originating from the waste management site (including composting plant and the landfill) located in the vicinity of protected areas. In this paper, the impact of urban and industrial facilities adjacent to the landfill is also investigated. The analysis of ammonium concentration was carried out for selected piezometers and then the monitoring and laboratory tests results were referred to the Polish standards of groundwater quality. The content of the paper discusses the changes of ammonium concentration in time and space and presents potential reasons for these changes, especially resulting from the construction of the vertical bentonite barrier. The results show the significant decrease of ammonium concentration and progressive improvement of water quality observed in almost every piezometer after a few years since the vertical barrier has been installed. Furthermore, the paper provides statistical analyses of groundwater monitoring data from the period 1998–2015 in order to control the groundwater quality and assess the movement of contamination plume in the landfill area.

https://www.mdpi.com/2071-1050/8/12/1253/pdf

Ammonium Concentration and Migration in Groundwater in the Vicinity of Waste Management Site Located in the Neighborhood of Protected Areas of Warsaw, Poland

Health risk assessment of heavy metals in drinking water leaching through improperly managed dumpsite waste in Kurata, Ijoko, Sango area of Ogun State, Nigeria

reciprocating engine consists of two driving parts, piston and rotor, when the engine start these two parts move with a certain frequency, resulting in vibrations in the structure. dynamic analysis of the structure aim to find out how the structure behaves due to vibrations generated from the machine, whether the structure is safe for the machine and humans around the machine due to the amplitude of displacement, velocity, and displacement from structure. This dynamic analysis is carried out with the help of SAP 2000 v20.20 software with a dynamic load in the form of a reciprocating compressor operating with a frequency of 49.16 Hz. In this final project, the machine foundation uses a table top type with 1x1.7 m column dimensions and 1.3x1.6 m beams. From the free vibration analysis, the result is a natural frequency structure, from the first ten modes the structure is declared safe from resonance However, in this study the displacement and velocity of structures that occur in the zone B & C while the acceleration into the safe category based on applicable standards. This means that the structure is safe for humans who are around but are not safe for the product and the machine itself if it operates for a long time continuously.

/pdf/analysis-and-dynamic-behavior-of-portal-structures-due-to-38igrm6j5h.pdf

Analysis and dynamic behavior of portal structures due to reciprocating machine

The analysis and design of machine foundation requires more attention since it involves not only the static loads but also the dynamic loads caused by the working of the machine. The limiting amplitude and operating frequency of a machine are the most important parameters to be considered in analysis of machine foundation. The Elastic half space analogy method with embedment coefficients can be used for coupled modes of vibration to get the natural frequencies and amplitudes of foundation vibrations. With effect to depth of embedment there has been increase in natural frequency but considerable decrease in amplitude of foundation vibrations.

/pdf/dynamic-analysis-of-machine-foundation-15d19krj1o.pdf

Dynamic Analysis Of Machine Foundation

Safe and reliable disposal of municipal solid wastes and residues is an important component of integrated waste management. Open dumps, commonly found in Asian countries, are land disposal sites at which solid wastes are disposed of in such a manner that does not protect the environment, susceptible to open burning, and exposed to disease vectors and scavengers. Leachate is a polluted liquid emanating from the base of the landfill, which contains innumerable organic and inorganic compounds generated due to which serious ground water contamination was observed in wells. Present paper is a case study of Uruli Devachi (Open dump site), near Pune (M.S.) where daily 1000–1200 tonnes of solid waste are disposed at Uruli-Devachi village, and the site was dealing with problems of frequent fires, smoke, flies, birds and bad odour. PMC was spraying the waste with water to prevent fires, resulting in even greater quantities of leachate generated due to which Serious ground water contamination was observed in wells

/pdf/ground-water-contamination-by-leachate-3mpvv0gsyp.pdf

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Papers

Dynamic Analysis Of Machine Foundation

Ground Water Contamination by Leachate