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The use of castellated beams has become more popular in the last two decades. The main idea for the use of these types of steel beams is to reduce their self-weight by providing openings in the web of wide flange (WF) or I sections. Numerous research on castellated beams has been conducted, the majority of the studies aimed to optimize the opening size and the shape configuration of the openings. A numerical analysis of castellated beams with oval openings was performed in this study. The sections under investigation had variations in the height-to-length ratios of the beam. The Do to D and b to Do ratios were kept at a constant. The D value was defined as the height of the beam, while Do is the height of the opening, and b is the width of the opening. The numerical analysis was performed by the finite element analysis using the STRAND7 software. The numerical model was further validated to the experimental data. The results showed that the developed finite element model resulted in a very good representation to the actual behavior of the sections.

Hard bremsstrahlung produced during the deceleration of fission-product beta rays in nuclear fuel is proposed as a source of delayed photoneutrons (PNs) in heavy water reactors. Electron Gamma Shower (EGS5) code simulations of coupled electron-photon transport in seven fuel element geometries immersed in an infinite heavy water medium confirm high-energy beta rays produce sufficient bremsstrahlung yields with photon energies greater than the D(γ,n)1H reaction threshold such that the beta-ray contribution to an isotopic PN yield can be comparable to or greater than yields from hard gamma rays emitted during the isomeric transition of the daughter, especially for some short-lived fission products with high-intensity direct-to-ground-state beta transitions where the beta ray and antineutrino carry away the majority of the Q-value. Some fission products that do not have hard gamma rays in their decay schemes are in fact PN precursors due to the beta-ray-bremsstrahlung contribution. The lack of evaluated nuclear data for many short-lived fission products, data reliability issues of fission products with decay scheme data, cross-section library effects, and possible decay-chain/parent-feeding phenomenon are affecting the accuracy of PN group parameters derived from a small number of legacy experiments. The reanalysis of two legacy PN experiments supports the existence of a very-short-lived direct-delayed neutron group. [ABSTRACT FROM AUTHOR]

Steel fiber waste is in the form of ductile and tough fibers, making it suitable for increasing the tensile strength and flexural strength of Self-Compacting Concrete (SCC). The use of rice husk ash (RHA) as an additive in SCC concrete is expected to improve the quality of SCC concrete while reducing the use of Portland cement as an adhesive. This study aims to examine the tensile strength and flexural performance of SCC concrete beams with rice husk ash added and steel wire scrap waste. The research was conducted by making a concrete beam specimen to examine the flexural performance, and a concrete cylinder test object to examine the tensile strength and compressive strength of concrete. The specimens were made with 4 variations; the variations used are distinguished based on the percentage of RHA and steel fiber waste. The results showed that the use of RHA in SCC concrete can increase the compressive strength of concrete. It is proven that concrete with RHA added increases compressive strength by 8.45%. The use of steel fiber waste in SCC RHA concrete can increase the tensile strength of concrete by 28.15%, increasing the flexural strength by 9.3%. So, it can be concluded that the addition of RHA and steel fiber waste to the SCC mixture can increase the strength of the SCC. [ABSTRACT FROM AUTHOR]

Excessive use of cement can cause damage to the environment. Using materials that have similar properties to cement as a concrete mixture can reduce the use of cement. Because the silica content in glass is quite large, glass has the potential to be used as a partial substitute for cement in concrete. This study aims to determine the effect of glass powder used as a partial cement substitute on the compressive strength of normal concrete. This study uses cylindrical specimens with 15 cm in diameter and 30 cm in height according to SNI 03-2834-2002. They were tested at seventh, fourteenth, and twenty-eighth day. The variations of the glass powder are 0%, 4%, 8%, 12%, and 16%. Based on the results of the testing at the twenty eighth days, the concrete's compressive strength at 0% variation is 22.8 MPa, at 4% variation is 24.0 MPa, at 8% variation is 17.5 MPa, at 12% variation is 17.6 MPa, and at 16% variation is 7.9 MPa. Thus, using glass powder as a partial substitute for cement in concrete mixtures affects the compressive strength of normal concrete. At the twenty-eighth day, the compressive strength of the concrete has increased by 5% to 24.0 MPa. [ABSTRACT FROM AUTHOR]

Concrete is one of Indonesia's most widely used construction materials. Thus, the need for concrete materials, mainly sand keeps increasing. Excessive sand mining will harm the environment, causing erosion and landslides. In addition, recent trends in construction have created negative impacts to the nature, such as the dumping of lightweight bricks remnant. This study was conducted to examine the use of lightweight brick waste as a substitute for fine aggregate on the compressive strength of concrete. The design of concrete in this research uses SNI 03 - 2834 - 2002 as the guidelines. The variations are 0%, 10%, 20%, and 30% of lightweight brick waste to replace fine aggregate. This research uses quantitative primary data to obtain the compressive strength of concrete. The tests were held on the seventh, fourteenth, and twentyeighth day of concrete age, and simple regression analysis was used to determine the effect of weight on the use of brick wastes as a partial substitution of fine aggregate on the compressive strength of concrete. The results show that the maximum and minimum compressive strengths were obtained in variation 10% and variation 30%, which produce the compressive strengths 24.45 MPa and 18.03 MPa at the twenty-eighth day of concrete. Based on the results of the simple regression analysis with SPSS, the use of lightweight brick waste has a significant effect on the compressive strength of twenty-eight day of concrete by 64.8% and the linear regression formula in this test can be written as Y = 24.3 -0.170x. [ABSTRACT FROM AUTHOR]