1,721,026 research outputs found
Modelling and on-line implementation of advanced control strategies for biohydrogen production in microbial electrolysis cell reactor system / Azwar Muhammad Yahya
Full text linkOne free energy source that is sustainable and renewable is the hydrogen gas. The most interesting fact about this gas is when used on vehicles or fuel cells, it is more efficient
than the conventional internal combustion engines.When these compounds react with air, the by-product is just water. Because of these advantages, the hydrogen gas is known as
a low-carbon energy source. This is one solution for modern society, so that the dependence on fossil fuels can be minimized. Other advantage of the hydrogen gas is that
it can be produced from various surrounding sources such as water, natural gas, biomass and organic waste. When viewed in terms of the economy, the selection of hydrogen fuel
as a source of alternative energy is very appropriate.
There are several alternative technologies for the production of biohydrogen process namely biophotolysis, photofermentation, dark fermentation and microbial electrolysis cells (MEC). However, MEC is known to be an attractive alternative technology that is environmentally friendly and can be used for hydrogen production. It involves a bioelectrochemical process using microorganisms as catalysts. MEC process has advantages compared with other processes because the microorganisms are capable of oxidizing all organic substrates to produce hydrogen gas which cannot be extracted by microorganisms through the photo or dark fermentation process. Microorganisms in the reactor are able to catalyze the oxidation or reduction reaction at the anode and cathode electrodes, respectively. By increasing the cathode potential in the MEC reactor, it is possible to continuously produce hydrogen electron exchange assisted by the bacteria. This method greatly decreases the amount of energy needed to produce hydrogen from organic matter compared to hydrogen production from water via electrolysis. Hydrogen production process in the MEC is a highly nonlinear and complex due to the microbial interactions. Its complexity makes MEC system difficult to operate and control under optimal conditions. However, these problems can be alleviated using an integrated process system engineering approach, which involves process modeling, optimization and control complementing each other. Artificial Neural Networks (ANN) is one of the most effective and powerful technique to be used to model such complex processes and unknown systems. ANN is able to cope with non-linear process between input and output variables without the requirement of explicit mathematical representation. In the process control system, ANN has been widely used when conventional control techniques failed to give good performance. In this work, various schemes including ANN for controlling the current and voltage of MEC were studied i.e. Direct Inverse Neural Network, Hybrid PID-Neural Network and Internal Model-based Control schemes. A comparative study has been carried out under optimal condition for the production of hydrogen gas where the controller output are based on the correlation of optimal current and voltage to the MEC system. Various simulation studies involving multiple set-point changes and disturbances rejection have been evaluated and the performances of both controllers are discussed. On-line model validation of MEC system and closed loop control for online system are also presented in this work
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
Analisis Perbaikan Tanah Pada Proyek Perluasan Dermaga Petikemas Belawan
No full textDewasa ini, studi kasus tentang penggunaan metode preloading dan prefabricated
vertical drain sebagai metode perbaikan tanah lunak sudah banyak di temui di
proyek-proyek konstruksi di Indonesia. Seiring dengan berkembangnya teknologi
di bidang kontruksi, banyak kegiatan kontruksi yang semakin fokus pada perilaku
tanah. Tanah merupakan salah satu komponen yang menunjang stabilitas suatu
struktur. Tanah sangat erat kaitannya dengan beban sehingga jika suatu struktur
dibangun di atas tanah tersebut, diharapkan tidak terjadi kerusakan dikemudian
hari. Hasil pemodelan dengan vertical drain, waktu yang dibutuhkan sejak
reklamasi pertama untuk mencapai derajat konsolidasi sebesar 90% adalah 540
hari. Hasil analisis konsolidasi menggunakan metode FEM dengan derajat 90%
dan tekanan air pori 1 kpa diperoleh penurunan sebesar 8,73 meter. Setelah
diakumulasikan ada selisih perbandingan antara metode PVD dan program
analitis (Plaxis) dengan kohesi ,BH-1= 7.84 kN/m2
, BH-2=8.33 kN/m2
,dan BH3= 1 kN/m2
. Selisih perbandingan antara penurunan elastis dan penurunan pada
program (Plaxis) dengan menggunakan parameter tanah dengan sudut geser BH1= 5 %, BH-2= 6 %, danBH-3= 29.5 %
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
Information Literacy Skills : Strategi Penelusuran Informasi Online
Full text linkThis book discusses about the Information Literacy Skills : Online Information Search Strategies. The writing in this book is essentially invites the scholars both at the level of schools and universities that currently live in the Internet age to learn information literacy skills, especially in terms of online information search strategy.
This paper also introduces the reader some online sites of scientific work that should be frequently accessed by students and faculty in fullfil their information needs on campus. These sites as well as a book or scientific work that we often encounter in the library, it's just a different format (digital). The online sites contains a lot of scientific information that can be accessed free of charge.
The author also introduces the concept of an online library that currently developing in Indonesia. Library users can take advantage of a variety of library services easily and quickly via Internet access.
At the end of the article, the author also describes the important role of librarians in promoting information literacy program to the user library.
The discussion in this book include optimizing the utilization of the features of Google, Google advanced search strategies, strategies of online information evaluation, online sites of scientific papers, open access journal, digital content of Republic Indonesia National Library, and online libraries
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