İnşaat Mühendisliği Bölümü Yayın Koleksiyonu
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Article Citation Count: Dinckal, Cigdem, "Design of integral spreadsheet calculator for engineering applications", Computer Applications In Engineering Education, Vol. 26, No. 5, pp. 1159-1172, (2018)Design of Integral Spreadsheet Calculator for Engineering Applications(Wiley, 2018) Dinçkal, Çiğdem; 26773Although Newton-Cotes integration formulas in engineering have been the subject of the study for a long time, the improvement in formulations is still object of interest. In this sense, design of calculators based on these formulations becomes significant. The purpose of this paper is to design an integral calculator for any engineering problems. Since the integral calculator, easy-to-understand and use, is aimed to be employed by any kind of users. Visual Basic for Applications (VBA) is the programming language of Excel. Excel spreadsheet with VBA is preferred for this purpose. In this study, a user interface input form is introduced. This form is composed of the embedded algorithm. This algorithm includes not only rules and formulations of each Newton-Cotes such as Composite Trapezoidal rule, Simpson's rules, Boole's rules, and Gauss Legendre formulations with 2, 6, 10, 16, and 24 points and exact result of any integral (if it exists) with computed true percent relative error for comparison purposes. This calculator is tested for civil, mechanical, and chemical engineering applications. The results and screenshots for each application obtained from calculator are presented. The present study allows design of an integral spreadsheet calculator for any integral given. If exact result of the integral cannot be obtainable, the calculator can perform only integral calculations numerically without exact solution and computed true percent relative error. Otherwise, user can solve the integrals completely with this tool easily and accurately again but this time by both numerically and analytically with true percent relative error calculations.Article Citation Count: Yildirim, Gurkan...et al. "Self-healing performance of aged cementitious composites", Cement & Concrete Composites, Vol 87, pp. 172-186, (2018)Self-Healing Performance of Aged Cementitious Composites(Elsevier SCI LTD, 2018) Yıldırım, Gürkan; Khiavi, Arash Hamidzadeh; Yeşilmen, Seda; Şahmaran, Mustafa; 177291This study investigates the autogenous self-healing capability of one-year-old engineered cementitious composites (ECC) with different mineral admixtures to understand whether self-healing performance in late ages is similar to that of early ages. Sound and severely pre-cracked specimens were subjected to different environmental conditions including water, air, "CO2-water," and "CO2-air" for one year plus 90 days of initial curing. Self-healing performance of ECC mixtures was assessed in terms of crack characteristics, electrical impedance testing, rapid chloride permeability testing and microstructural analysis. Laboratory findings showed that the presence of water is crucial for enhanced autogenous self-healing effectiveness, regardless of mixture composition. "CO2-water" curing resulted in the best self-healing performance of all curing conditions, which was confirmed with results from different performance tests throughout the experimental study. By further curing specimens under "CO2-water" (depending on the ECC mixture composition), cracks as wide as half a millimeter (458 mu m) were easily closed by autogenous self-healing within only 30 days of further curing, and all cracks closed completely after 90 days. Because high levels of CO2 emission are a global problem, the effectiveness of "CO2-water" curing in closing microcracks of aged cementitious composites specimens through autogenous self-healing can help reduce the increasing pace of CO2 release. The results of this study clearly suggest that late-age autogenous self-healing rates of ECC specimens can be significantly enhanced with proper further environmental conditioning and mixture design. (C) 2018 Elsevier Ltd. All rights reserved.