1,720,969 research outputs found
Prediksi Pengaruh Komposisi Pada Sifat Mekanik Bata Ringan Dengan Menggunakan Jaringan Syaraf Tiruan
Full text linkDalam fabrikasi bata ringan, salah satu permasalahan yang
ditemui adalah penentuan komposisi bahan baku dari bata
ringan yang dibuat. Ini karena komposisi bahan baku dari bata
ringan dapat mempengaruhi sifat mekanik dari bata ringan yang
menjadi parameter baik tidaknya bata ringan sebagai bahan
bangunan. Dalam tugas akhir ini telah dilakukan prediksi
pengaruh komposisi unsur penyusun dan densitas terhadap
kekuatan tekan bata ringan AAC dengan menggunakan jaringan
syaraf tiruan. Selain itu juga dilakukan simulasi pengaruh
komposisi unsur-unsur utama bata ringan AAC serta densitas
AAC terhadap kekuatan tekannya. Jaringan syaraf tiruan
dengan arsitektur feed forward backpropagation dan algoritma
pelatihan Levenberg-Marquardt yang terbaik didapatkan pada
hidden node 8, dengan MSE pelatihan sebesar 0,001605667 dan
MSE validasi sebesar 0,01455. Hasil simulasi pengaruh
komposisi dan densitas terhadap kekuatan tekan bata ringan
AAC menunjukkan bahwa komposisi Ca, Si, dan densitas
berbanding lurus terhadap kekuatan tekan AAC, sementara
komposisi Al berbanding terbalik dengan kekuatan tekan AAC.
Hasil prediksi kuat tekan yang didapatkan untuk 4 sampel AACa,
AAC-b, AAC-c, dan AAC-d secara berurutan adalah 4,80
MPa, 5,24 MPa, 3,23 MPa, dan 3,67 MPa.
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One of the problems found in the fabrication of lightweight
brick is how to determine the composition of raw materials used.
The composition of materials in lightweight brick can affect its
mechanical properties which is an important parameter for
building materials. In this study the prediction of the effect of
elements composition and density on compressive strength of
Autoclaved Aerated Concrete (AAC) using neural network has
been done. Furthermore, the simulation on the effect of each
element composition and the density on compressive strength
also has been done. The best network developed in this study
using feedforward backpropagation architecture and Levenberg-
Marquardt algorithm is to use 8 hidden node, with mse training
of 0.001605667 and mse validation of 0.01455. Simulation
results show that composition of Ca, Si, O, and density are all
directly proportional to compresssive strentgh, while
composition of Al is inversely proportional. The compressive
strength prediction results obtained for 4 AAC samples are 4.80
MPa, 5.24 MPa, 3.23 MPa, and 3.67 MPa for sample AAC-a,
AAC-b, AAC-c, and AAC-d sequentially. The result of prediction
shows that the neural network developed can predict the effect of
composition and density on compressive strength of AAC
Sintesis dan Karakterisasi Material Feroelektrik Sistem BaTiO3 - PbZrO3 - NaVO3
No full textMaterial bersifat feroelektrik adalah salah satu material yang diteliti dalam perkembangan dunia elektronika, karena dapat dikembangkan sebagai sensor dan kapasitor. Salah satu material bersifat feroelektrik yang terkenal dan memiliki struktur perovskite adalah Barium Titanat (BaTiO3). Material BaTiO¬3 disintesis dengan metode kopresipitasi oksalat untuk menghasilkan serbuk prekursor yang homogen dengan temperatur kalsinasi rendah sekitar 600oC-700oC.
Pada penilitian ini, BaTiO3 didoping dengan material perovskite lainnya yaitu PbZrO3, yang dikenal memiliki nilai permitivitas dielektrik yang tinggi, serta NaVO3 yang mempunyai titik leleh yang rendah untuk menurunkan temperatur kalsinasi dan sintering. Ketiga prekursor hasil sintesis dari BaTiO3, PbZrO3 dan NaVO3 dicampurkan sesuai perhitungan stoikiometri dengan metode solid state reaction untuk mendapatkan sistem (1-x-y)BaTiO3-xPbZrO3-yNaVO3 dengan x = 0.15 dan y = 0.025. Kemudian dilakukan karakterisasi TGA untuk menentukan temperatur kalsinasi. Setelah kalsinasi, dilakukan pembuatan pellet dan sintering dengan variasi temperatur, dan dipilih temperatur sintering dengan shrinkage yang baik dan densitas yang tinggi. Sintering dilakukan dengan dua metode, yaitu metode single-step dan multistep. Kemudian dilakukan pengukuran densitas, karakterisasi struktur dengan uji XRD, karakterisasi miksrotruktur dengan uji SEM dan karakterisasi sifat listrik dari material.
Didapatkan bahwa fasa utama dalam penelitian ini, yaitu BaTiO3 menjadi fasa minoritas untuk sintering ¬single-step pada temperatur 1250oC. Sementara pada temperatur yang sama dengan metode sintering multistep didapatkan bahwa fasa BaTiO3 adalah mayoritas. Pengujian sifat listrik juga menunjukkan bahwa sampel sintering multistep memiliki permittivitas relatif yang lebih tinggi dari temperatur kamar hingga 100oC, yang merupakan temperatur operasi alat elektronik umumnya. Sementara dielectric loss dari sampel multistep lebih rendah dan quality factor-nya lebih tinggi pada frekuensi rendah.
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Ferroelectric materials are one group of materials that are being studied in the development of electronics, as it can be used as sensor and capasitor. Barium Titanate (BaTiO3) is one of those ferroelectric materials, which also has a perovskite structure. Barium Titanate is synthesized by the oxalate coprecipitate method. In this research, BaTiO3 is doped by other perovskite-based material namely PbZrO3, which is known to have a high dielectric permittivity, and NaVO3 which has a low melting point. The dopant PbZrO3 are synthesized by sol-gel autocombustion method while NaVO3 are synthesized by the solid state reaction method. Then, the precursors of BaTiO3, PbZrO3, and NaVO3 are mixed according to stoichiometry and using the solid state reaction method to obtain a sistem of (1-x-y)BaTiO3-xPbZrO3-yNaVO3 with x = 0.15 and y = 0.025.
Thermogravimetric analysis (TGA) characterization was done to determine the right temperature for calcination. After calcination, the samples are pressed into pellets and the sintering is done with a variation of temperatur, and the sintering temperature which gives a good shrinkage and a high density is chosen. Afterwards, density measurement, structure characterization from X-Ray Diffraction (XRD) measurement, microstructure characterization from Scanning Electron Microscopy (SEM) measurement, and the electrical property characterization were done for the materials.
It was found that the main phase in this study, BaTiO3, is the minority phase for single-step sintering at a temperature of 1250oC. While at the same temperature for multistep sintering method, it was found that the BaTiO3 phase was the majority. The electrical properties test showed that the multistep sintering samples had higher permittivity from room temperature to 100oC. The dielectric loss of the multistep sample is lower than the single-step sample and its quality factor is higher in low frequencies
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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