18 research outputs found
Waste glass aggregate for cementitious and polymer concrete
WOS: 000386109100008Glass waste is produced in considerable amounts annually. Due to the disadvantageous nature of its recycling process, its reuse gains importance. Given the high reactivity level of glass-incorporating mixtures, the reuse of waste glass as aggregate in polymer concrete was investigated. Polymer concrete mixtures, including unsaturated polyester resin, hardener and accelerator, waste glass aggregate (up to 8 mm) and glass fabrics, were prepared for the investigation of mechanical properties. The composite specimens were reinforced by means of glass fabrics in various types (woven or mat), amounts (single or double layer) and orientation (perpendicular or parallel to loading direction). The mechanical properties of polymer concretes were tested for flexural tensile strength and compressive strength. In addition, thermal conductivity and residual strength after elevated temperatures were determined. It was concluded that these composites with easy preparation techniques have superior mechanical and thermal insulation properties compared with their counterparts available for use and their mechanical properties were mainly affected by the amount, type and orientation of the glass fabric reinforcement.Scientific and Technical Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [110M569]; EBILTEMEge University [2012-BIL-023]The financial support of Scientific and Technical Research Council of Turkey (TUBITAK) under grant no. 110M569 and EBILTEM under grant no. 2012-BIL-023 are greatly acknowledged. The authors would like to thank Bugra Yigit Cetin, Begenc Saveliyev and Leyla Kokcu for their help in this experimental study
Improving the mechanical and durability performance of recycled concrete aggregate-bearing mortar mixtures by using binary and ternary cementitious systems
WOS: 000456755400027Environmental concerns arising from the generation of huge amount of construction and demolition waste requires recycling this material, which would otherwise be sent to landfill. The mechanical and durability performance of mortar mixtures containing recycled concrete (RC) aggregate was investigated in this study. Although it is known that the adhered mortar creates a porous and a weak additional interfacial transition zone in recycled aggregate-bearing mixture, the dependence of the behavior on the type of new matrix should be searched in detail. For this purpose, compressive strength, ultrasound pulse velocity, water absorption, chloride ion penetration, freeze-thaw and sulfate resistance as well as drying shrinkage tests were conducted on mortar mixtures containing either natural aggregate (sand) or recycled concrete aggregate. Scanning electron micrographs and optical microscope images were obtained on specimens exposed to sulfate attack. The mineral admixtures used in the study included silica fume (SF), metakaolin (MK) and a Class C fly ash (FA). In addition to the control mixture including no mineral admixture (PC), silica fume- and metakaolin-incorporating binary systems (PC-SF and PC-MK) were prepared. Besides, two ternary systems, i.e., PC-SF-FA and PC-MK-FA were also designed. The results indicated a gradual strength gain beyond 28 days and reduction in initial shrinkage values in RC-bearing mixtures, compared to those of the sand-bearing mixtures. Besides, the porous character of RC helped reducing the internal pressure and resultant damage related with expanding water and swelling ettringite crystals in freeze-thaw and sulfate attack tests, respectively. The exact effect of recycled aggregate on mortar properties was found to be greatly dependent on the type of the cementitious system of the new mix. (C) 2018 Elsevier Ltd. All rights reserved.Uludag University Scientific Research Projects Centre (BAP) [KUAP(MH)-2017/11]The authors would like to thank Izmir Cimentas Cement Plant and Polisan Construction Chemicals Company authorities for their kind assistance in providing the cement, mineral admixture and water reducing admixture as well as determining the chemical composition, physical and mechanical properties of these products. Besides, the first author gratefully acknowledge support provided by Uludag University Scientific Research Projects Centre (BAP) under Grant numbers KUAP(MH)-2017/11
Evaluation of three test methods for determining the alkali-silica reactivity of glass aggregate
WOS: 000319086400007Consumption of natural raw materials and pollution have become significant problems due to technological developments and continual increase in demand. Accordingly, great efforts are being made in order to recover wastes including glass. One of the possible applications is utilizing waste glass in concrete; however, alkali-silica reaction (ASR) is of major concern. In this study, tests were conducted by applying three different procedures: ASTM C1293, RILEM AAR-2, and microbar test methods. In microbar testing, glass aggregate was used as coarse aggregate, whereas the other two methods dealt with investigating the reactivity of the finer fraction of the waste glass. The effects of chemical composition, particle size and amount of glass in the mixture were studied. According to the results, flint glass expanded to a greater extent than amber and green glass. Expansions, within the specified time periods dictated by the methods, remained low; however, extended durations resulted in very high length change values of the flint glass-including mixtures, particularly in the MR-2 and microbar tests. (C) 2013 Elsevier Ltd. All rights reserved
Left Atrial Giant Cell Myocarditis Presenting as a Tumor: First-in-Man Case Report
Abstract Giant cell myocarditis is a rare and highly lethal disorder with resultant cardiac insufficiency. It necessitates aggressive immune suppression therapy, although the results are often fatal. When it affects only the atria, the characteristics of the disease changes completely. In this case report, we present atypical presentation of atrial giant cell myocarditis with mass lesion, which completely resolved after successful surgical resection without immuno suppression therapy
Damage severity of wood-destroying insects according to the Bevan damage classification system in log depots of Northwest Turkey
The aim of the study was to determine damage severity of wood-destroying insects on logs stored in forest depots. The Bevan damage classification (BDC) system, developed in 1987, was utilized to determine damage severity in log depots in 21 locations throughout seven provinces in Turkey. Pheromone traps were placed in those locations at the beginning of April in 2015 and 2016. Furthermore some stored wood within the log depots were checked and split into small pieces to collect insects that damage wood. The BDC system was used for the first time to measure the severity of insect damage in log depots. Twenty-eight families, 104 genera and 123 species were identified in this study. Based on the BDC system, the highest damage was found from the Cerambycidae and Buprestidae families. Arhopalus rusticus was determined as the insect responsible for the highest amount of damage with 8.8% severity rating in the pheromone-trapped insects group. When the stored wood material was considered, Hylotrupes bajulus was found to be the cause of the highest damage. The lowest damage values were among the predator insects (Cleridae, Trogossitidae, Cantharidae) and those feeding on fungi colonized on the wood (Mordellidae, Cerylonidae, Nitidulidae). Some other predator insects of the Tenebrionidae family (Uloma cypraea, Uloma culinaris, Menephilus cylindricus) and Elateridae family (Lacon punctatus, Ampedus sp.) exhibited relatively higher damage severity values since they had built tunnels and made holes in the stored wood material. When the environmental factors were considered, the Buprestidae family exhibited a very strong positive relationship (p<0.005) with insect frequency distribution (r=0.922), number of species (r=0.879) and insect density (r=0.942). Both families showed the highest number and frequency during July and August, highlighting the importance of insect control and management during these months.TUBITAK-COST ProjectTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114O850]This study was supported by TUBITAK-COST Project No. 114O850. The authors thank Dr. Goksel Tozlu (Buprestidae), Dr. Celal Karaman (Formicidae), Dr. Bekir Keskin (Tenebrionidae), Dr. Suleyman Akbulut (Curculionidae) and Tsuyoshi Yoshimura (Rhinotermitidae) for the identification some insect species. The authors thank Nuriye Peachy for contributions in developing and editing the English text of the manuscript.WOS:0005635469000012-s2.0-85089431178PubMed: 3279260
Relationship between first trimester visualization of the intracranial translucency and spina bifida
To establish a reference range for the intracranial translucency (IT)
Analysis of the effects of hypothalamic-pituitary-adrenal axis activity in menstrual cycle on ankle proprioception, dynamic balance scores and visual-auditory reaction times in healthy young women
Objectives: Menstrual cycle (MC) can affect not only the female reproductive system, but also functions such as neuromuscular performance. For this reason. the aim of this study is to investigate the effect of hypothalamic-pituitary-adrenal axis (HPA) activity in MC on proprioception, balance and reaction times. Methods: For cortisol analysis, saliva samples were taken from the same women (n=43) in the four phases of MC. While State Trait Anxiety Inventory-I (STAI-I) was applied in each phase to support cortisol analysis, pain was measured with visual analogue scale (VAS). Proprioception, dynamic balance, visual and auditory reaction times (VRT-ART) measurements were made in the four phases of MC. Results: Cortisol, STAI-I and VAS scores, angular deviations in proprioception measurements, dynamic balance scores, VRT and ART measurements were found to show statistically significant difference between MC phases (p<0.05). As a result of the post hoc test conducted to find out which MC phase the statistical difference resulted from, it was found that statistically significant difference was caused by the mensturation (M) phase (p<0.05). Conclusions: It was found that neuromuscular performance and postural control was negatively affected by HPA axis activity in M phase of MC and by pain, which is a significant menstrual symptom.WOS:0006253048000092-s2.0-85102483218PubMed: 3365775
Left Atrial Giant Cell Myocarditis Presenting as a Tumor: First-in-Man Case Report
<div><p>Abstract Giant cell myocarditis is a rare and highly lethal disorder with resultant cardiac insufficiency. It necessitates aggressive immune suppression therapy, although the results are often fatal. When it affects only the atria, the characteristics of the disease changes completely. In this case report, we present atypical presentation of atrial giant cell myocarditis with mass lesion, which completely resolved after successful surgical resection without immuno suppression therapy.</p></div