Sürdürülebilir Kalkınma Amaçları
Yazarlar
- Bayrakdaroglu, Serdar(2)
- Ceylan, Halil Ibrahim(2)
- Etli, Serkan(2)
- Yılmaz, Tekin(2)
- Akpinar, Salih(1)
- Almeida-Neto, Paulo(1)
- Alsaran, A.(1)
- Aydin, Murat Demir(1)
- Bayrak, O.(1)
- Biyikli, Turker(1)
- Celik, A.(1)
- Demir Şahin, Demet(1)
- Eker, Hasan(1)
- Hacisalihoglu, I.(1)
- Hansu, Osman(1)
- Kacoglu, Celil(1)
- Karaman, I.(1)
- Kayhan, Recep Fatih(1)
- Kirkaya, Izzet(1)
- Nikolaidis, Pantelis T.(1)
- Oliveira, Cesar Chaves(1)
- Purcek, G.(1)
- Temiz, Şemsettin(1)
- Terzi, Esranur(1)
- Uğur Yayla(1)
- Vangolu, Y.(1)
- de Assis, Gilmara Gomes(1)
- Özel, Adnan(1)
- Özkan, Ali(1)
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ1Thermochemical Activation of Lightweight Slag–Perlite Alkali-Activated Slag (AAS): Overcoming Aggregate Brittleness and Sulfate Degradation
Eker, Hasan; Demir Şahin, Demet
The successful realization of a circular economy in the cement industry, coupled with a substantial reduction in carbon emissions, relies on the development of sustainable alternative binder systems. This study investigated the physicomechanical performance and sulfate resistance of composites produced by alkali activation of natural perlite and blast furnace slag. The aim of the research was to improve mechanical properties under low- and medium-alkalinity conditions (5–10 M NaOH). The samples were cured at an ambient temperature of 20 °C and then treated with heat at 60 °C. These samples were then mechanically processed and subjected to five soak–dry cycles in 5% and 10% Na2SO4 solutions. The results showed that heat treatment resulted in the formation of a dense C-A-S-H gel, increasing compressive strength approximately eightfold, from 11.64 MPa to 92 MPa. However, perlite’s porous and brittle structure limits its flexural strength to 0.27 MPa; this value is insufficient for structural applications. Under severe sulfate attack (10% Na2SO4), samples cured at ambient temperature showed a 12% mass increase in the first cycle due to solution infiltration into capillary voids. As a consequence of extensive ettringite and gypsum formation, the specimens experienced severe deterioration, resulting in a complete loss of mechanical integrity and a residual compressive strength of 0 MPa. In contrast, heat-treated samples showed limited ion diffusion due to a denser matrix and an improved aggregate interface transition zone, resulting in a 2.6% mass increase and a residual compressive strength of 5.17 MPa. Consequently, the obtained findings indicate that thermally treated alkali-activated slag–perlite composites exhibit high resistance against sodium sulfate attack and may have potential for use in specific industrial environments with high sulfate concentrations. However, the performance of these materials under more complex aggressive conditions, such as mining environments involving magnesium sulfate exposure and acidic drainage waters, should be further validated through future studies.
AtıfScopus1WoS1OpenAlex1İncele - MakaleAçık Erişim2025Scopus SJRQ2Comprehensive study on the role of mycrisparite in enhancing strength, stability, and microstructural traits of self-compacting mortars
Etli, Serkan; Yılmaz, Tekin
The present research work aims at promoting the mechanical, durability and microstructure performances of self-compacting mortars (SCMs) and lessening the cement production-induced costs and environmental difficulties, by replacing binder with definite proportions (2.5–15%) of MS. To achieve these goals, the compressive and flexural strength (UCS, FS), freeze–thaw (F–T), sorptivity (Sp), MIP (tP, psD) and SEM tests were conducted on SCMs cured for diverse (7–90 days) ages. The outcomes unearthed that replacing binder with MS at small proportions boosted the UCS/FS performances of SCMs. These improvements in strength performance compared to MS-0 were more spectacular in MS-2.5, which produced higher UCS and FS of 8.6–21.0% and 10.0–25.7%, respectively at all curing ages. Similarly, the same SCMs, which betrayed lower UCS- (10.3 < 16.7) and FS-losses (31.6 < 41.0) than the control at the end of the 200-cycle F–T test, were able to remain more endurance against F–T deterioration. Besides, MS replacement up to 10% enabled the SCMs to exhibit lower tP- (up to 11.2%) and Sp values (up to 61.2%) by ameliorating the psD (refining the larger pores into finer pores). The current research can be consequently commented to provide more beneficial SCM design on both strength/stability and microstructure, and cost and environmental troubles for the building industry.
AtıfScopus4WoS5OpenAlex6İncele - MakaleAçık Erişim2024Scopus SJRQ1Isometric Shoulder and Hip Strength Impact on Throwing Velocity and Reactive Strength
Kayhan, Recep Fatih; Terzi, Esranur; Bayrakdaroglu, Serdar; Ceylan, Halil Ibrahim; Biyikli, Turker
The aim of the study is to examine relationships between shoulder extension-flexion and internal-external rotation strength of professional male handball players with throwing velocity, and the hip extension-flexion strength with horizontal and vertical reactive strength index. Fifteen professional male handball players participating in 1 st League matches took part in the study. The results showed that isometric shoulder flexion and extension strength significantly predicted stable throwing velocity (r (2 )=between 0.27-0.73) and dynamic throwing velocity (r( 2) =between 0.30-0.62). In addition, isometric internal and external rotation strength significantly predicted stable throwing velocity (r (2) =between 0.32-0.54) and dynamic throwing velocity (r (2) =between 0.31-0.44). Moreover, isometric hip extension and flexion strength significantly predicted vertical reactive strength index (r( 2) =between 0.31-0.45) and horizontal reactive strength index (r (2) =between 0.26-0.42). In conclusion, it was observed that shoulder strength has an enhancing effect on handball players' throwing velocity, while hip strength is a determining factor for the reactive strength index. In this context, it is assumed that shoulder weakness during throwing will affect the accuracy and velocity of throwing by disrupting the angular momentum, while weakness in the hip during the jump phase of the throwing motion will negatively affect the explosive power by limiting stabilization during landing.
AtıfWoS4OpenAlex6İncele - MakaleAçık Erişim2024Scopus SJRQ1Effect of White-Portland cement containing micro and nano silica on the mechanical and freeze-thaw properties of self compacting mortars
Etli, Serkan; Yılmaz, Tekin; Hansu, Osman
This study concentrated to investigate the influences of white-Portland cement (W-PC) containing silica fume (SF: micro-silica (µSi) and nano-silica (nSi)) as replacement (2–4 wt%) on mechanical (strength and durability), physical and microstructural behaviors of self-compacting mortars (SCMs) fabricated at 0.48–0.63 w/b ratios. In keeping with these purposes, besides of carrying out the workability (mini-slump flow: M−SF and V-funnel: V-F) experiments of SCMs, the mechanical and microstructural tests implemented were: unconfined compressive strength (UCS), flexural strength (FS), freeze–thaw (F-T) and scanning electron microscope (SEM) analysis. The outcomes displayed that, in comparison with the control, replacing W-PC by SF (particularly nSi) enhanced the UCS and FS, resisted against F-T durability by lowering the strength losses in UCS and FS. The ameliorated microstructure resulting in a reduction in the number and/or a narrowing in the size of micro-cracks and pores contributed to generate a more compact and consolidated SCM structure for the improving of strength and durability due of pore-filling effect and superior pozzolanic characteristics of µSi and especially nSi, this in turn reduced the permeability of SCM, which has a significant effect on the strength and durability behaviors of the SCM.
AtıfScopus16WoS16OpenAlex19İncele - MakaleAçık Erişim2024Scopus SJRQ1Pre-Exercise Caffeine and Sodium Bicarbonate: Their Effects on Isometric Mid-Thigh Pull Performance in a Crossover, Double-Blind, Placebo-Controlled Study
Kacoglu, Celil; Kirkaya, Izzet; Ceylan, Halil Ibrahim; de Assis, Gilmara Gomes; Almeida-Neto, Paulo; Bayrakdaroglu, Serdar; Oliveira, Cesar Chaves; Özkan, Ali; Nikolaidis, Pantelis T.
Caffeine and sodium bicarbonate are extensively researched ergogenic aids known for their potential to enhance exercise performance. The stimulant properties of caffeine on the central nervous system, coupled with the buffering capacity of sodium bicarbonate, have been associated with improved athletic performance. This has led to investigations of their combined effects on strength. The aim of the present study is to investigate the effect of isolated and combined caffeine and sodium bicarbonate consumption on strength using the isometric mid-thigh pull test (IMTP). Nineteen male college students (age 23.6 +/- 1.6 years) participated in this crossover, double-blind, placebo-controlled study. They were exposed to the following conditions: control (no supplement), placebo (20 g maltodextrin), caffeine (6 mg/kg), sodium bicarbonate (0.3 g/kg), and a combination of caffeine and sodium bicarbonate. Supplements and placebo were diluted in water and consumed 60 min prior to the IMTP tests. Two 5 s IMTP trials were performed at 40-60% and 60-80% of One Repetition of Maximum (1RM) with a 60 s rest between. Consumption of caffeine or Caf + NaHCO3 did not significantly change peak IMTP strength values at any intensity (p = 0.110). The peak IMTP values did not show significant differences between conditions or from control condition values (1091 +/- 100 N) to Caf (1224 +/- 92 N), NaHCO3 (1222 +/- 74 N), and Caf +/- NaHCO3 (1152 +/- 109 N). However, the test of the results of the ANOVA analysis of repeated measures of effect within the caffeine condition was significant for the increase in IMTP relative strength compared to control (p < 0.05). Thus, the IMTP force values increased significantly from control to Caf (p = 0.016) and from Pla to Caf (p = 0.008), but not for other comparisons (p > 0.05). In summary, caffeine supplementation alone, taken 60 min before exercise, positively affects submaximal strength performance. In contrast, sodium bicarbonate, whether taken alone or in combination with caffeine, does not enhance submaximal strength in the IMTP tests.
AtıfScopus5WoS6İncele - Doktora TeziAçık Erişim2020Bireysel afet direnç değerlendirmesi: Gümüşhane örneği
Uğur Yayla
Araştırma, "Individual Disaster Resilience Assessment (InDRA)" Ölçeğinin geçerliliğini ve güvenilirliğini yaparak Türkçeye "Bireysel Afet Direnç Değerlendirmesi (BADD)" ölçeği olarak uyarlayıp sonraki çalışmalar için literatüre katkı sağlamak amacıyla yapılmıştır. Ölçeğin uygulaması Gümüşhane Üniversitesinde öğrenim gören 622 öğrenciye anket uygulayarak yapılmıştır. Araştırmamızın sonucunda elde edilen uyum indeksleri sonuçları en iyi değerleri içermektedir. Araştırma grubundaki katılımcıların cinsiyet, afetlerle ilgili hazırlık eğitimi alma, afetlerle ilgili hazırlık eğitimi isteme, afet planı hakkında bilgisi olma, afet-acil durum çantası olma, afet planı olma, ilk yardım eğitimi alma, ilk yardım eğitimi isteme ve deprem sonrası buluşma yeri belirleme durumları ile bireysel afet direnç değerlendirme (BADD) puanları ortalaması arasında istatistiksel olarak anlamlı bir farklılık bulunmuştur (p<0,05). Araştırma grubundaki katılımcıların BADD puanları ortalaması açısından gelir grupları arasında istatistiksel olarak anlamlı bir farklılık bulunmuştur (p<0,05). Araştırma grubundaki kadınlar ile erkeklerin afet yaşama durumları arasında istatistiksel olarak anlamlı bir farklılık bulunamamıştır (p>0,05). Araştırmada afet eğitimi alanların afet hazırlık plan bilgisi olanlar ile arasında istatistiksel olarak anlamlı farklılık bulunmuştur (p<0,05). Sonuç olarak, tüm bulgular nazarında ölçme aracının yeni faktörlü yapısı bu araştırma kapsamında doğrulanmış olup, Türkiye'de güvenilirliği ve geçerliliği yüksek 20 maddeden oluşan yeni bir Bireysel Afet Direnç Değerlendirme Ölçeği'ne ulaşılmıştır. BADD ölçeğini farklı örneklemlere uygulayarak literatür zenginleştirilmelidir.
- MakaleYalnız künye2013Scopus SJRQ13-D non-linear stress analysis on the adhesively bonded T-joints with embedded supports
Akpinar, Salih; Aydin, Murat Demir; Temiz, Şemsettin; Özel, Adnan
In the present study, it is aimed to compare mechanical behaviors of T-joint types with embedded and non-embedded supports subjected to bending moment. For this purpose, after experimental studies on the two different T-joint types were conducted, stress analyses in the T-joints were performed with a three-dimensional finite element method by considering the geometrical non-linearity and the material non-linearities of the adhesive (DP460) and adherend (AA2024-T3). Finally, stress analyses and experimental results show that the variation of the geometry of the bonding zone, e.g., embedding the supports, would change the stress distributions and strength of the joint. Additionally, it is seen that T-joints with embedded supports carry 30% more load than T-joints with non-embedded supports although their bending stiffnesses decrease.
AtıfScopus17WoS15OpenAlex19İncele - BildiriYalnız künye2011Scopus SJRQ1Hydroxyapatite production on ultrafine-grained pure titanium by micro-arc oxidation and hydrothermal treatment
Alsaran, A.; Purcek, G.; Hacisalihoglu, I.; Vangolu, Y.; Bayrak, O.; Karaman, I.; Celik, A.
In this study, pure-Ti (Grade-2) was severely plastically deformed by equal-channel angular extrusion (ECAE) to improve its strength, and then subjected to micro arc oxidation (MAO) and hydrothermal treatment (HT) to achieve improved surface behavior with hydroxyapatite (HA)-containing titania (TiO(2)) coating. Microstructure, tensile properties and wear behavior of UFG Ti were investigated systematically before and after surface modification. ECAE considerably enhanced the strength of coarse-grained (CG) Ti by forming an ultra-fine grained (UFG) microstructure with high dislocation density. The application of MAO with or without HT did not cause remarkable decrease in strength and ductility of CG and UFG Ti, but resulted in a considerable increase in its wear resistance and osseointegration due to the formation of hard and adhered HA-containing TiO2 coating on the surface. It can be concluded that the use of ECAE plus MAO/HA coating provides a simple and effective procedure to obtain pure Ti with high strength and high wear resistance. The improved bulk and surface properties can make this biocompatible material a good potential candidate for biomedical applications instead of alloys including toxic elements. (C) 2011 Elsevier B.V. All rights reserved.
AtıfScopus61WoS61OpenAlex65İncele