1,720,974 research outputs found
Investigation of the effect of high temperature on glass powder, brick powder and tile powder added geopolymer mortars
No full textFen Bilimleri Enstitüsü, İnşaat Mühendisliği Ana Bilim Dalı, İnşaat Mühendisliği Bilim DalıBu çalışmanın temel amacı, çevreye verilen zararı azaltmak ve sürdürülebilir bir yaşam için atık malzemelerden üretilen geopolimer harçların yüksek sıcaklık etkisi altındaki dayanımlarını belirlemektir. Deneylerde silis-alümin kökenli malzeme olarak yüksek fırın cürufu (YFC), cam tozu (CT), fayans tozu (FT) ve tuğla tozu (TT) kullanılmış, alkali aktivatör olarak da NaOH tercih edilmiştir. Başlangıçta, YFC kullanılarak farklı molarite (6 M, 8 M, 10 M, 12 M) ve kür sıcaklıklarında (60°C, 80°C, 100°C) geopolimer harçlar hazırlanmış ve en uygun koşullar 12 M ve 100°C kür sıcaklığı olarak belirlenmiştir. Sonrasında YFC'nin yerine CT, FT ve TT farklı oranlarda ikame edilerek 2'li ve 3'lü karışımlı numuneler hazırlanmış ve dayanım açısından en iyi ikame oranları tespit edilmiştir. Bu numuneler yüksek sıcaklığa (300°C, 600°C, 900°C) maruz bırakılmış, suda ve havada soğutma işleminin ardından dayanım özellikleri, kütle kayıpları ve diğer özellikler belirlenmiştir. Çalışmanın sonucunda elde edilen veriler atık malzemelerden üretilen geopolimer harçların çevre dostu ve sürdürülebilir inşaat malzemeleri olarak kullanım potansiyelini doğrulamıştır.The primary objective of this study is to determine the mechanical properties of geopolymer mortars produced from waste materials under high-temperature conditions, aiming to reduce environmental impact and promote sustainable living. In the experiments, materials derived from silica-alumina sources such as blast furnace slag (BFS), glass powder (GP), tile powder (TP), and brick powder (BP) were utilized, with NaOH chosen as the alkali activator. Initially, geopolymer mortars of different molarity (6 M, 8 M, 10 M, 12 M) and curing temperatures (60°C, 80°C, 100°C) were prepared using BFS and the most suitable conditions were determined as 12 M and 100°C curing temperatures.Subsequently, 2-part and 3-part mixtures were prepared by substituting BFS with different proportions of GP, TP, and BP, and the best replacement ratios were identified based on strength. These samples were subjected to high temperatures (300°C, 600°C, 900°C) and after cooling in water and air, their strength properties, mass losses, and other characteristics were determined. The data obtained as a result of the study confirmed the potential of using geopolymer mortars produced from waste materials as environmentally friendly and sustainable construction materials
Mechanical and durability properties of cementitious composite systems having similar fineness of fly ash, granulated blast furnace slag and bottom ash
No full textFen Bilimleri Enstitüsü, İnşaat Mühendisliği Ana Bilim DalıGelişen sanayi ile birlikte endüstriyel alandaki üretimin yoğunlaşması sonucu birçok atık malzeme ortaya çıkmaktadır. Bu atıkların büyük bir kısmı yığınlar halinde biriktirilerek çevre kirliliğine neden olmaktadır. Bunu önlemek amacıyla atık maddelerin çeşitli sektörlerde kullanılması gerekmektedir. Enerji sarfiyatı yüksek olan çimento sektörü, aynı zamanda dünya sera gazı salınımında önemli bir paya sahiptir. Uçucu kül, yüksek fırın cürufu, taban külü ve doğal puzolan gibi çimento yerine kullanılabilecek puzolanlar yardımıyla gerçekleştirilen katkılı çimento üretimi, enerji sarfiyatını, endüstriyel atıkların değerlendirilmesi ve ekolojik olumsuzlukları indirgemek için uygulanabilecek yöntemlerden biridir. Bahsedilen endüstriyel atıkların çimento üretiminde kullanılması CO2 emisyonunu, enerji sarfiyatını ve buna bağlı olarak da çimento üretiminden kaynaklanan ekolojik olumsuzlukların etkisini azaltacaktır. Çimento üretimini daha ekonomik hale getirerek çevresel koşullara asgari düzeyde etki edecek çimento üretim sürecini gerçekleştirebilmek amacıyla bu çalışmada belirli bir blaine incelik değerinde (?3300 cm2/gr) öğütülen uçucu kül, yüksek fırın cürufu ve taban külünün çimento harçlarına ikame edilerek çimento harçlarının basınç dayanımı, boyca uzama miktarları, klorür iyonu geçirimliliği ve taramalı elektron mikroskobu (SEM) yardımıyla mikro yapısı incelenmiştir. Sonuç olarak belirli bir blaine incelik değerinde öğütülen çimento bağlayıcı kompozitlerin çimento harcında dayanım ve dayanıklılık özelliklerine etkisi karşılaştırılmış ve yüksek fırın cürufunun bu özellikleri maksimum oranda iyileştirdiği görülmüştür. Uçucu külün dayanım ve dayanıklılık değerleri yüksek fırın cürufu ikameli numunelere göre daha düşük olmakla birlikte dayanıklılık özellikleri bakımından yüksek fırın cürufuna yakın değerler vermektedir. Taban külünün dayanım değerleri çalışmada kullanılan diğer çimento bağlayıcı kompozitlere nazaran az olsa da çimento harcının dayanıklılık özelliklerini olumlu yönde etkilediği gözlemlenmiştir. Anahtar kelimeler: Çimento Harcı, Yüksek Fırın Cürufu, Uçucu Kül, Taban Külü, Özgül Yüzey Alanı, Basınç ve Eğilme Dayanımı, Klor GeçirimliliğiIn addition to the developing industry, many waste materials are released as a result of production in the industry. A large part of these waste materials are stored and unfortunately this causes environmental pollution. In order to prevent this situation, these materials should be used in various sectors. The cement industry, where energy consumption is very high, also plays an important role in the global greenhouse gas emissions. The production of blended cement with the help of pozzolans that can be used instead of cement such as fly ash, blast furnace slag, bottom ash and natural pozzolan is one of the methods that can be applied to reduce energy consumption, industrial waste and ecological negativity. By using the industrial wastes in cement productions mentioned above, it is aimed to reduce the impact of CO2 emission, energy consumption and ecological negativities arising from cement production. In this study, we aimed to ensure the cement production process that will affect the environmental conditions at a minimum level by making the cement production more economical. To this end, the fly ash, blast furnace slag, and bottom ash grounded within a certain amount of blaine fineness (?3300 cm2/g) are substituted into the cement mortars. The microstructure of cement mortars was evaluated by scanning electron microscopy (SEM) and the compressive strength, the length change, rapid chloride ion permeability of cement mortars was studied. According to the results obtained from the experiments, the effect of puzzolans grounded in a certain amount of blaine fineness on the strength and durability properties in cement mortar was compared and it was observed that blast furnace slag improved these properties at a maximum rate. The strength and durability values of fly ash are lower than the blast furnace slag replacement samples, but it gives values close to the blast furnace slag in terms of durability properties. Although the strength values of the bottom ash are less than the other cement binding composites used in the study, it has been observed that it has a positive effect on the durability properties of the cement mortar. Keywords: Cement Mortar, Blast Furnace Slag, Fly Ash, Bottom Ash, Specific Surface Area, Compressive and Flexural Strength, Rapid Chloride Permeability Tes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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