1,720,966 research outputs found
Preparation of Terminalia catappa Shell Based Activated Carbon by Microwave Assisted Chemical Activation
Full text linkActivated carbon was prepared from Terminalia catappa shells using microwave asissted KOH activation. The ratio of mass percentages of Terminalia catappa and KOH were 4:1, 4:2, and 4:3. Terminalia catappa based activated carbon was prepared by KOH activation at the room temperature for 24 hours and followed by microwave irradiation at the out put power of 630 Watt for 20 minutes. The physical properties of activated carbon i.e. surface morphology, micro structure, and BET surface area were characterized by electron scanning microscope, X-ray diffraction and N2 adsorption-desorption isotherm at 77K, respectively. The highest BET surface area was 312 m2/g with adsorption of activated carbon towards methylene blue by 84.4 mg/g. The BET surface area was directly correlated with the stack height (Lc) of the activated carbon
Cyclic Voltammometry of Binderless Activated Carbon Monoliths based supercapacitor from Mixtures of Pre-carbonized of Fibers of Empty Fruit Bunches and Green Petroleum Coke
Full text linkBinderless activated carbon monoliths (BACMs) prepared from mixtured of pre-carbonized of fibers of oil palm empty fruit bunches (EFB) and green petroleum coke were used for preparing the carbon based supercapacitor cells. The symmetrical supercapacitor cells were fabricated by using two BACMs electrode prepared for each selected holding time of activation and various compression pressure. The electrochemical behavior of supercapacitor cells were measured at room temperature by using cyclic voltammetry (CV) technique. The maximum specific capacitance (Csp) of the cells values were 35.9 and 82.5 F/g for holding time of activation of 1.5 and 2 h, respectively, at the compression pressure of 7.5 metric tons.
Synthesis of activated carbon electrodes from date seeds with a variety of separators for supercapacitor cell applications
Full text linkAbstrak. Karbon aktif yang berasal dari biomassa telah menjadi bahan elektroda paling kompetitif untuk superkapasitor karena sifatnya yang terbarukan dan berkelanjutan. Upaya optimalisasi dilakukan untuk proses pembuatan sel superkapasitor dengan memvariasikan separator agar dapat memperoleh kapasitansi spesifik yang tinggi. Biomassa biji kurma sebagai bahan dasar pembuatan elektroda karbon melalui proses prakarbonisasi, aktivasi kimia dengan aktivator KOH 0,3M, proses karbonisasi dengan suhu 650oC dialiri gas nitrogen. Penyusutan massa karbon sebesar 24,59%. Nilai densitas dari elektroda karbon setelah dilakukan proses karbonisasi adalah 0,852 g cm-3. Analisis struktur mikro menunjukkan bahwa elektroda karbon bersifat amorf ditunjukkan dengan adanya puncak pada sudut 2θ sekitar 24o dan 44o. Kapasitansi spesifik ditentukan dengan metode Cyclic Voltametry dan didapati sebesar 217,22; 176,18; dan 82,8 F/g masing-masing untuk variasi separator kertas whatman, kertas saring, dan membran telur ayam. Hasil penelitian menunjukkan bahwa pada kertas whatman merupakan separator terbaik untuk elektroda karbon dari biji kurma. Oleh karena itu karbon aktif yang dibuat dari biji kurma dengan biaya rendah, ketersedian mudah, dan berkelanjutan dapat diaplikasikan sebagai bahan elektroda untuk superkapasitor.
Abstract. Activated carbon derived from biomass has become the most competitive electrode material for supercapacitors due to its renewable and sustainable nature. Optimization efforts are made for the process of making supercapacitor cells by varying the separator in order to obtain a high specific capacitance. Date seed biomass as the basic material for making carbon electrodes through a pre-carbonization process, chemical activation with a KOH activator of 0.3M, the carbonization process at a temperature of 650oC flowed with nitrogen gas. Shrinkage of carbon by 24.59%. The density value of the carbon electrode that was carried out by the carbonization process was 0.852 g.cm-3. The microstructure analysis showed that the carbon electrode was amorphous indicated by the presence of a peak at an angle of 2θ around 24o and 44o. Specific capacitance was determined by the Cyclic Voltametry method and was found to be 217.22, 176.18, and 82.8 F/g respectively for the Whatman paper, filter paper, and chicken egg membrane separator variations. The results showed that whatman paper was the best separator for carbon electrodes from date palm seeds. Therefore, activated carbon made from date seeds with low cost, easy availability, and sustainability can be applied as an electrode material for supercapacitors.
Keywords: Date seed, Activated Carbon, Supercapacitor, Carbon Electrode, Separato
The Preliminary Study of Utilization of Water Chestnut as Supercapacitor Electrode Using Steam Activation
Full text linkPurun tikus (eleocharis dulcis) merupakan tumbuhan gulma yang bersifat polutan di perairan tawar. Efek pertumbuhan purun tikus yang cepat menyebabkan pendangkalan perairan, gangguan sistem irigasi dan pengurangan oksigen bawah air. Salah satu upaya pemanfaatan purun tikus yang bernilai tambah tinggi adalah purun tikus sebagai elektroda karbon superkapasitor. Karbon aktif berasaskan purun tikus dibuat dengan metode dua langkah secara simultan yaitu karbonisasi pada suhu 600C dalam lingkungan nitrogen dan aktivasi fisika menggunakan uap air pada suhu 900C selama 1 jam. Densitas karbon aktif menurun dari 0,85 menjadi 0,78 gr/cm3 setelah diaktivasi. Sifat elektrokimia elektroda karbon diukur dengan metode siklik voltammetri. Kapasitansi spesifik elektroda karbon masing-masing 58, 33 dan 23 F/g pada laju imbasan 1, 2 dan 5 mV/s. Hasil penelitian ini menunjukkan bahwa purun tikus dapat dijadikan elektroda superkapasitor dan menjadi solusi untuk mengurangi kerusakan ekosistem perairan tawar.Water chestnut are polluted weed plant in fresh water. The effect of rapid growth of water chestnut causes siltation of water, irigation system disturbance and reduction of oxygen underwater. One of the effort of the value added utilization of water chestnut is as carbon electrode for supercapacitor application. Water chestnut based activated carbon is prepared by a two-step method simultaneously i.e. carbonization at 600C in a nitrogen atmospheric and physical activation using steam at 900 C for a hour. The density of activated carbon after activation is decreased from 0,85 to 0,78 gr/cm3. The electrochemical properties of the carbon electrode are measured using cyclic voltammetry method. The specific capacitance of carbon electrode are 59, 33 and 23 F/g at the scan rate of 1, 2 and 5 mV/s, respectively. The result of this study are indicated that water chestnut suitable for supercapacitor electrode and become a solution to reduce the freshwater ecosystem damage.Keywords: Purun tikus, superkapasitor, siklis voltammetri, kapasitansi spesifik, perairanREFERENCEAsikin, S. dan Thamrin, M. 2012. Manfaat Purun Tikus (Eleocharis Dulcis) Pada Ekosistem Sawah Rawa. Jurnal Litbang Pertanian, 31(1): 35-42Arepalli, S., Fireman, H., Huffman, C., Moloney, P., Nikolaev, P., Yowell, L., Higgins, C. D., Kim, K., Kohl, P. A., Turano, S. P. and Ready W. J. 2005. Carbon-nanotube-based electrochemical double-layer capacitor technologies for spaceflight applications. Journal of The Minerals, Metals and Materials Society, 57:26-31.Erari, S.S., Mangimbulude, J., Lewerissa, K. 2012. Pencemaran Organik di Perairan Pesisir Pantai Teluk Youtefa Kota Jayapura, Papua. Prosiding Seminar Nasional Kimia Unesa. ISBN 978-979-028-550-7. (C): 327-340.Farma, R., Deraman, M., Awitdrus, A., Talib, I.A. Taer, E., Basri, N.H., Manjunatha, J.G., Ishak, M.M., Dollah, B.N.M., Hashmi, S.A. 2013. Preparation of highly porous binderless activated carbon electrodes from fibres of oil palm empty fruit bunches for application in supercapacitors. Bioresource Technology. 132:254261Feng, C.W., R.L. Tseng., C.C. Hu., C.C Wang., 2015, Effects of pore structure and electrolyte on the capasitive characteristics of steam and KOH activated carbons for supercapasitors, Journal of power sources. 144:302-309.Ionnidou, A and Zabaniotu. 2007. Agricultural residues of precursors for activated carbon productiona review, Renewable and sustainable energy reviews. 11:1705-1966.Kurniawan, F., Wongso, M., Ayucitra, A., Soetaredjo F.E., Angkawijaya A. E., Ju,Y. H., Ismadji, S. 2014. Carbon microsphere from water hyacinth for supercapacitor electrode. Journal of the Taiwan Institute of Chemical Engineers. 47: 197-201.Liu, B., Zhou, X., Chen, H., Liu, Y., Li, H. 2016. Promising porous carbons derived from lotus seedpods with outstanding supercapacitance performance. Electrochimica Acta. 208 :5563.Taer, E., Mustika, W.S., Zulkifli, Syam, I.D.M., Taslim, R. Pengaruh Suhu Pengaktivan CO2 Terhadap Luas Permukaan Elektroda Karbon dan Sifat Kapasitan Sel Superkapasitor dari Kayu Karet. 2015. Prosiding Seminar Nasional Fisika Universitas Andalas (SNFUA). 96-100Taer, E., Taslim, R., Aini, Z., Hartati, S.D., Mustika, W.S. 2017. Activated carbon electrode from banana-peel waste for supercapacitor applications. AIP Conference Proceedings. 1801:040004-1-040004-4.Taer, E., Zulkifli., Arif, E.N., Taslim, R. Analisa Kapasitansi Spesifik Elektroda Karbon Superkapasitor dari Kayu Karet Terhadap Laju Scan Berdasarkan Variasi Aktivasi HNO3. 2016. Spektra Jurnal Fisika dan Aplikasinya. 1(1): 35-40.Yu, M., Han, Y., Li, J., Wang, L., 2016. CO2-activated porous carbon derived from cattail biomass for removal of malachite green dye and application as supercapacitors. Chemical Engineering Journal. 17:1-41
The Preliminary Study of Utilization of Water Chestnut as Supercapacitor Electrode Using Steam Activation
No full textPurun tikus (eleocharis dulcis) merupakan tumbuhan gulma yang bersifat polutan di perairan tawar. Efek pertumbuhan purun tikus yang cepat menyebabkan pendangkalan perairan, gangguan sistem irigasi dan pengurangan oksigen bawah air. Salah satu upaya pemanfaatan purun tikus yang bernilai tambah tinggi adalah purun tikus sebagai elektroda karbon superkapasitor. Karbon aktif berasaskan purun tikus dibuat dengan metode dua langkah secara simultan yaitu karbonisasi pada suhu 600°C dalam lingkungan nitrogen dan aktivasi fisika menggunakan uap air pada suhu 900°C selama 1 jam. Densitas karbon aktif menurun dari 0,85 menjadi 0,78 gr/cm3 setelah diaktivasi. Sifat elektrokimia elektroda karbon diukur dengan metode siklik voltammetri. Kapasitansi spesifik elektroda karbon masing-masing 58, 33 dan 23 F/g pada laju imbasan 1, 2 dan 5 mV/s. Hasil penelitian ini menunjukkan bahwa purun tikus dapat dijadikan elektroda superkapasitor dan menjadi solusi untuk mengurangi kerusakan ekosistem perairan tawar.
Water chestnut are polluted weed plant in fresh water. The effect of rapid growth of water chestnut causes siltation of water, irigation system disturbance and reduction of oxygen underwater. One of the effort of the value added utilization of water chestnut is as carbon electrode for supercapacitor application. Water chestnut based activated carbon is prepared by a two-step method simultaneously i.e. carbonization at 600°C in a nitrogen atmospheric and physical activation using steam at 900 °C for a hour. The density of activated carbon after activation is decreased from 0,85 to 0,78 gr/cm3. The electrochemical properties of the carbon electrode are measured using cyclic voltammetry method. The specific capacitance of carbon electrode are 59, 33 and 23 F/g at the scan rate of 1, 2 and 5 mV/s, respectively. The result of this study are indicated that water chestnut suitable for supercapacitor electrode and become a solution to reduce the freshwater ecosystem damage.
Keywords: Purun tikus, superkapasitor, siklis voltammetri, kapasitansi spesifik, perairan
REFERENCE
Asikin, S. dan Thamrin, M. 2012. Manfaat Purun Tikus (Eleocharis Dulcis) Pada Ekosistem Sawah Rawa. Jurnal Litbang Pertanian, 31(1): 35-42
Arepalli, S., Fireman, H., Huffman, C., Moloney, P., Nikolaev, P., Yowell, L., Higgins, C. D., Kim, K., Kohl, P. A., Turano, S. P. and Ready W. J. 2005. Carbon-nanotube-based electrochemical double-layer capacitor technologies for spaceflight applications. Journal of The Minerals, Metals and Materials Society, 57:26-31.
Erari, S.S., Mangimbulude, J., Lewerissa, K. 2012. Pencemaran Organik di Perairan Pesisir Pantai Teluk Youtefa Kota Jayapura, Papua. Prosiding Seminar Nasional Kimia Unesa. ISBN 978-979-028-550-7. (C): 327-340.
Farma, R., Deraman, M., Awitdrus, A., Talib, I.A. Taer, E., Basri, N.H., Manjunatha, J.G., Ishak, M.M., Dollah, B.N.M., Hashmi, S.A. 2013. Preparation of highly porous binderless activated carbon electrodes from fibres of oil palm empty fruit bunches for application in supercapacitors. Bioresource Technology. 132:254–261
Feng, C.W., R.L. Tseng., C.C. Hu., C.C Wang., 2015, Effects of pore structure and electrolyte on the capasitive characteristics of steam and KOH activated carbons for supercapasitors, Journal of power sources. 144:302-309.
Ionnidou, A and Zabaniotu. 2007. Agricultural residues of precursors for activated carbon production–a review, Renewable and sustainable energy reviews. 11:1705-1966.
Kurniawan, F., Wongso, M., Ayucitra, A., Soetaredjo F.E., Angkawijaya A. E., Ju,Y. H., Ismadji, S. 2014. Carbon microsphere from water hyacinth for supercapacitor electrode. Journal of the Taiwan Institute of Chemical Engineers. 47: 197-201.
Liu, B., Zhou, X., Chen, H., Liu, Y., Li, H. 2016. Promising porous carbons derived from lotus seedpods with outstanding supercapacitance performance. Electrochimica Acta. 208 :55–63.
Taer, E., Mustika, W.S., Zulkifli, Syam, I.D.M., Taslim, R. Pengaruh Suhu Pengaktivan CO2 Terhadap Luas Permukaan Elektroda Karbon dan Sifat Kapasitan Sel Superkapasitor dari Kayu Karet. 2015. Prosiding Seminar Nasional Fisika Universitas Andalas (SNFUA). 96-100
Taer, E., Taslim, R., Aini, Z., Hartati, S.D., Mustika, W.S. 2017. Activated carbon electrode from banana-peel waste for supercapacitor applications. AIP Conference Proceedings. 1801:040004-1-040004-4.
Taer, E., Zulkifli., Arif, E.N., Taslim, R. Analisa Kapasitansi Spesifik Elektroda Karbon Superkapasitor dari Kayu Karet Terhadap Laju Scan Berdasarkan Variasi Aktivasi HNO3. 2016. Spektra Jurnal Fisika dan Aplikasinya. 1(1): 35-40.
Yu, M., Han, Y., Li, J., Wang, L., 2016. CO2-activated porous carbon derived from cattail biomass for removal of malachite green dye and application as supercapacitors. Chemical Engineering Journal. 17:1-41
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
Characterization of Physical Properties for Activated Carbon from Garlic Skin
Full text linkAbstrak. Karbon aktif yang berasal dari biomassa telah menjadi bahan material dasar yang sudah digunakan secara luas untuk berbagai aplikasi eperti penyerapan, absorben, elektroda, penyimpan energi, dan aplikasi lainnya. Oleh karena itu perlu untuk pengoptimalkan sumber mentah karbon aktif berbiaya rendah dan memiliki porositas yang tinggi. Biomassa kulit bawang putih sebagai bahan dasar pembuatan karbon aktif melalui proses pra-karbonisasi, aktivasi kimia dengan aktivator KOH dan ZnCl2 dengan masing-masing kosentrasi sebesar 0,25 M, 0,5 M, dan 0,75 M dan tanpa aktivator kimia. Proses karbonisasi dengan suhu 600°C dialiri gas nitrogen dan diaktivasi fisika dengan suhu 850°C. Penyusutan massa karbon sebesar 29,4%. Nilai densitas dari elektroda karbon untuk aktivator KOH dengan kosentrasi 0,5M yaitu 0,64 g.cm-3dan untuk aktivator ZnCl2 dengan kosentrasi 0,5M yaitu 0,71 g.cm-3. Gugus fungsi yang dimiliki elektroda kulit bawang putih diidentifikasi sebagai C-C, C C (alkuna), C-H (alkana), dan (O-H) yaitu pada bilangan gelombang 1600 cm-1, 1500 cm-1, 2950 cm-1 dan 2900-3600 cm-1. Hasil penelitian menunjukkan bahwa pada aktivator KOH dan ZnCl2 dengan kosentrasi 0,5 M kondisi terbaik untuk variasi guna menunjang pengoptimalkan sumber mentah karbon aktif dan bisa digunakan dalam berbagai apliasi yang lebih luas.
Abstract. Activated carbon derived from biomass has become a basic material that has been used widely for various applications such as absorption, absorbent, electrodes, energy storage, and other applications. Therefore, it is necessary to optimize the raw source of activated carbon which is low cost and has high porosity. Garlic skin biomass as a basic material for making activated carbon through a pre-carbonization process, chemical activation with KOH and ZnCl2 activators with concentrations of 0,25 M, 0,5 M, and 0,75 M respectively and without chemical activators. The carbonization process with a temperature of 600°C is flowed with nitrogen gas and is physically activated at a temperature of 850°C. Shrinkage of carbon by 29.4%. The density value of the carbon electrode for the KOH activator with a concentration of 0.5M is 0.64 g.cm-3 and for the ZnCl2 activator with a concentration of 0,5M is 0,71 g.cm-3. The functional groups possessed by the garlic skin electrode were identified as C-C, C = C (alkynes), C-H (alkanes), and (O-H), namely at the wave numbers 1600 cm-1, 1500 cm-1, 2950 cm-1 and 2900-3600 cm-1. The results showed that the KOH and ZnCl2 activators with a concentration of 0.5 M were the best conditions for variation in order to optimize the raw source of activated carbon and could be used in a wider variety of applications
- …
