1,720,957 research outputs found
Studi Perilaku Pasta Geopolymer Ordinary Portland Cement Hybrid
Full text linkAbstrak Kuat tekan awal pada pasta geopolymer akan tinggi jika menggunakan bantuan perawatan panas. Hal ini karena reaksi geopolimer bersifat endotermik. Ini adalah salah satu hambatan aplikasinya. Paper ini bertujuan memaparkan karakteristik pasta geopolimer-OPC hybrid tanpa perawatan panas. Pasta geopolimer-Portland semen hybrid diperoleh dengan memvariasi prosentase subtitusi OPC terhadap fly ash yaitu 0%, 5%. 10% dan 15%. Parameter yang ditinjau adalah konsistensi, Setting time dan kuat tekan. Hasil pengujian menunjukan karakteristik pasta geopolimer-OPC hybrid bahwa Nilai konsistensi lebih kecil dari konsistensi normal OPC, Semakin tinggi prosentase subtitusi fly ash setting time awal dan akhir semakin singkat kurang dari 1 jam, namun kuat tekan semakin meningkat. Hal menunjukkan bahwa geopolimer-OPC hybrid dapat digunakan untuk pekerjaan pengecoran yang membutuhkan waktu pengikatan awal yang singkat misalnya paving blok atau lapisan perkerasan jalan. Kata kunci: Karakteristik, Pasta, Geopolimer, Ordinary Portland Cement, Hybrid Abstract Heat treatment on the geopolymer paste can result in high early compressive strength because the geopolymer reaction is endothermic. This condition is one of the obstacles to its application. This article describes the characteristics of geopolymer-Portland cement hybrid pastes without heat treatment. The hybrid geopolymer-Portland cement paste was obtained by varying the percentage substitution of Portland cement to fly ash, namely 0%, 5%, 10%, and 15%. Parameters observed are consistency, setting time, and compressive strength. The results show the characteristics of the hybrid geopolymer-Portland cement paste Its consistency is smaller than standard Portland cement. The higher the percentage of substitution, the initial and the final setting time are shorter, less than one hour, but the compressive strength increases. This shows that hybrid geopolymer-Portland cement can be used for the works that require a short initial setting time, such as paving blocks or road pavement layers. Keywords: Characteristic, Paste, Geopolymer, Ordinary Portland Cement, Hybri
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
Pengaruh Pemodelan Zona Terkekang Terhadap Prediksi Hubungan Momen-Kurvatur Kolom Persegi Beton Mutu Tinggi
Full text linkAbstrak. Paper ini mengkaji salah satu aspek yang berkaitan dengan pemodelan daerah terkekang pada kolom persegi beton mutu tinggi yang diberi beban aksial tekan eksentrik. Cakupan daerah terkekang pada penampang kolom adalah parameter yang dikaji untuk melihat pengaruhnya terhadap prediksi analitis kekuatan dan daktilitas kolom. Beberapa pemodelan daerah terkekang yang sering digunakan dalam berbagai literature dievaluasi untuk mengetahui karakteristik dan sensitivitasnya. Selanjutnya dalam paper ini dikembangkan program komputer MOKUR2D untuk menganalisis hubungan momen-kurvatur kolom persegi beton mutu tinggi. Dalam program, cakupan daerah terkekang pada penampang kolom dapat dimodelkan dengan tiga pendekatan, yaitu pendekatan model konvensional yang menggunakan koefisien kekangan efektif, model dengan daerah arching action yang tak terkekang dan model penampang dengan tiga variasi derajat kekangan yang berbeda. Studi perbandingan dengan menggunakan program tersebut kemudian dilakukan terhadap 4 buah kolom yang diuji oleh Sheikh dan Bayrak [1998]. Semua kolom tersebut berdimensi 305 x 305 mm, dengan delapan tulangan longitudinal berdiameter 19.5 mm yang terdistribusi merata pada penampang. Tegangan leleh tulangan baja yang digunakan adalah 454 MPa. Dua tipe konfigurasi sengkang yang dikaji masing-masing adalah sengkang diamond dan konvensional dengan volumetric ratio berkisar antara 1.68 hingga 5.24 persen. Spasi tulangan sengkang yang terpasang berkisar antara 90 mm hingga 108 mm. Hasil analisis menunjukkan bahwa pemodelan daerah terkekang dengan model konvensional masih cukup akurat walaupun sedikit overestimate terhadap hasil eksperimen sedangkan model dengan tiga variasi derajat kekangan terlihat memiliki akurasi respon teoritis momen kurvatur yang lebih baik dan sangat mendekati hasil eksperimen jika kekangan pada daerah arching action ditetapkan sebesar 50% dari kekangan pada inti kolom.Abstract. This paper studies one aspect of confinement modeling of high strength concrete square columns subjected to axially eccentric compression. Confined zone models were studied to evaluate their effect on the analytical prediction of strength and ductility of high strength concrete square columns. Several models of confined zones found in literatures were discussed to observe their characteristics and sensitivity. Based on the findings, a computer program MOKUR2D was developed. In the program, confined zone in reinforced concrete columns can be modeled with three different approaches, i.e. conventional models (using a coefficient of effective confinement), models with unconfined arching zone, or models with three zones of confinement. A comparative study using the program was later carried out on 4 high-strength concrete square columns tested by Sheikh and Bayrak [1998]. The cross-section size of all columns was 305 x 305 mm. All columns were reinforced with 8 bars of 19.5 mm diameter, uniformly distributed around the core perimeter. Yield strength of the rebars was 454 MPa. Two types of ties configuration ties were used with volumetric ratio varying from 1.68 percent to 5.12 percent. The spacing of the ties was from 90 mm to 108 mm. From the study, it was found that the conventional model is able to produce a fairly good estimate of test results. The best estimate of test results is given by the model with three zones of confinement in which the arching zoneis assigned with 50% of full confinement
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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