Journal articles: 'Pores of Kohn'

1

Ng, Calvin SH, Rainbow WH Lau, Kelvin KW Lau, Malcolm J. Underwood, and Anthony PC Yim. "Defeating the pores of Kohn." Asian Cardiovascular and Thoracic Annals 22, no. 1 (January 2014): 102–4. http://dx.doi.org/10.1177/0218492312474454.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Bastacky, J., and J. Goerke. "Pores of Kohn are filled in normal lungs: low-temperature scanning electron microscopy." Journal of Applied Physiology 73, no. 1 (July 1, 1992): 88–95. http://dx.doi.org/10.1152/jappl.1992.73.1.88.

Full text

Abstract:

Interalveolar pores of Kohn, small uniform-sized epithelium-lined openings in alveolar walls of normal lung, have historically been demonstrated with electron-microscopic techniques that remove water. We show these pores to be present but almost invariably filled with material when water and surfactant are preserved in frozen hydrated lung examined with low-temperature scanning electron microscopy. In the normal mouse, 16 open empty pores per alveolus were found in instillation-fixed dried lung vs. less than 1 per alveolus in frozen hydrated lungs (P less than 0.001). In the normal rat, 13 pores were seen per alveolus in instillation-fixed dried lung vs. less than 1 per alveolus in frozen hydrated lungs (P less than 0.001). We suggest that pores of Kohn 1) function primarily as conduits for interalveolar movement of alveolar liquid, surfactant components, and macrophages, 2) provide distributed sites for tubular myelin storage without increasing gas diffusion pathway thickness in the alveolar subphase itself, and 3) do not function as pathways for collateral ventilation during normal breathing in the absence of atelectasis or obstruction.

APA, Harvard, Vancouver, ISO, and other styles

3

Lu, De-fu, Charles Stanley, German Nunez, and David Frazer. "A Mathematical Description of Pressures in Alveolar Pores of Kohn." Journal of Biomechanical Engineering 113, no. 1 (February 1, 1991): 104–7. http://dx.doi.org/10.1115/1.2894075.

Full text

Abstract:

Small interalveolar holes within the lung are called pores of Kohn. Some researchers have correlated enlarged pore size with diseases, e.g. emphysema, that are characterized by tissue destruction. Mathematical models of the pressures generated in closed, fluid-filled and open, fluid-lined pores demonstrate that pressures capable of rupturing lung tissue can be developed in a pore due to the surface tension and shape of the air-liquid interface. Pore enlargement accompanied by tissue destruction is presented as a possible mechanism for the disease process observed during aging and the development of emphysema in the lung.

APA, Harvard, Vancouver, ISO, and other styles

4

Oldham, Michael J., and Owen R. Moss. "Pores of Kohn: forgotten alveolar structures and potential source of aerosols in exhaled breath." Journal of Breath Research 13, no. 2 (March 27, 2019): 021003. http://dx.doi.org/10.1088/1752-7163/ab0524.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Parra, Saundra C., Ricky Burnette, and Timothy Takaro. "Computer Reconstructions of Normal Human Alveoli From Serial Sections." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 312–13. http://dx.doi.org/10.1017/s0424820100118436.

Full text

Abstract:

Portions of two adjacent normal human alveoli were reconstructed from serial sections in order to examine normal alveolar organization, including anatomical relationships among the different cell types, the connective tissue matrix and gaps in the alveolar septum. Computer reconstructions were prepared from montaged electron micrographs of serial sections. Rotation of these reconstructions in the x, y or z axes allowed examination of the alveoli from many different aspects other than the actual plane of sectioning. Anatomical relationships “between Type I and Type II epithelial cells, alveolar macrophages, and pores of Kohn that could not he deduced from a single plane of the section (random sections) were revealed.

APA, Harvard, Vancouver, ISO, and other styles

6

Peão, M. N. D., A. P. Águas, C. M. de Sá, and N. R. Grande. "Morphological Evidence for Migration of Particle-Laden Macrophages through the Interalveolar Pores of Kohn in the Murine Lung." Cells Tissues Organs 147, no. 4 (1993): 227–32. http://dx.doi.org/10.1159/000147509.

Full text

APA, Harvard, Vancouver, ISO, and other styles

7

Xi, Jinxiang, Mohamed Talaat, Hesham Tanbour, and Khaled Talaat. "Airflow and Particle Deposition in Acinar Models with Interalveolar Septal Walls and Different Alveolar Numbers." Computational and Mathematical Methods in Medicine 2018 (September 25, 2018): 1–18. http://dx.doi.org/10.1155/2018/3649391.

Full text

Abstract:

Unique features exist in acinar units such as multiple alveoli, interalveolar septal walls, and pores of Kohn. However, the effects of such features on airflow and particle deposition remain not well quantified due to their structural complexity. This study aims to numerically investigate particle dynamics in acinar models with interalveolar septal walls and pores of Kohn. A simplified 4-alveoli model with well-defined geometries and a physiologically realistic 45-alveoli model was developed. A well-validated Lagrangian tracking model was used to simulate particle trajectories in the acinar models with rhythmically expanding and contracting wall motions. Both spatial and temporal dosimetries in the acinar models were analyzed. Results show that collateral ventilation exists among alveoli due to pressure imbalance. The size of interalveolar septal aperture significantly alters the spatial deposition pattern, while it has an insignificant effect on the total deposition rate. Surprisingly, the deposition rate in the 45-alveoli model is lower than that in the 4-alveoli model, indicating a stronger particle dispersion in more complex models. The gravity orientation angle has a decreasing effect on acinar deposition rates with an increasing number of alveoli retained in the model; such an effect is nearly negligible in the 45-alveoli model. Breath-holding increased particle deposition in the acinar region, which was most significant in the alveoli proximal to the duct. Increasing inhalation depth only slightly increases the fraction of deposited particles over particles entering the alveolar model but has a large influence on dispensing particles to the peripheral alveoli. Results of this study indicate that an empirical correlation for acinar deposition can be developed based on alveolar models with reduced complexity; however, what level of geometry complexity would be sufficient is yet to be determined.

APA, Harvard, Vancouver, ISO, and other styles

8

Shimura, Sanae, Edwin S. Boatman, and C. J. Martin. "Effects of ageing on the alveolar pores of Kohn and on the cytoplasmic components of alveolar type II cells in monkey lungs." Journal of Pathology 148, no. 1 (January 1986): 1–11. http://dx.doi.org/10.1002/path.1711480103.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Fukuoka, Junya, Akira Yoshikawa, Shuntaro Sato, Tomonori Tanaka, Mikiko Hashisako, Yukio Kashima, Tomoshi Tsuchiya, Naoya Yamasaki, Takeshi Nagayasu, and Hiroshi Yamamoto. "Breakdown of lung framework and an increase in pores of Kohn as initial events of emphysema and a cause of reduction in diffusing capacity." International Journal of Chronic Obstructive Pulmonary Disease Volume 11 (September 2016): 2287–94. http://dx.doi.org/10.2147/copd.s114281.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Jin, Yongyang, and Genkai Zhang. "Fundamental Solutions of Kohn Sub-Laplacians on Anisotropic Heisenberg Groups and H-type Groups." Canadian Mathematical Bulletin 54, no. 1 (March 1, 2011): 126–40. http://dx.doi.org/10.4153/cmb-2010-086-1.

Full text

Abstract:

AbstractWe prove that the fundamental solutions of Kohn sub-LaplaciansΔ+iα∂t on the anisotropic Heisenberg groups are tempered distributions and have meromorphic continuation in α with simple poles. We compute the residues and find the partial fundamental solutions at the poles. We also find formulas for the fundamental solutions for some matrix-valued Kohn type sub-Laplacians on H-type groups.

APA, Harvard, Vancouver, ISO, and other styles

11

Wang, Chao-Ge, Shi-Liang Liu, and Fang Wu. "Two new species of Perenniporia (Polyporales, Basidiomycota)." MycoKeys 69 (July 9, 2020): 53–69. http://dx.doi.org/10.3897/mycokeys.69.51652.

Full text

Abstract:

Two new species of Perenniporia, P. pseudotephroporasp. nov. and P. subcorticolasp. nov., are introduced respectively from Brazil and China based on morphological characteristics and molecular data. Perenniporia pseudotephropora is characterised by perennial, pileate basidiocarps with distinctly stratified tubes, grey pores, tissues becoming dark in KOH, a dimitic hyphal system with slightly dextrinoid arboriform skeletal hyphae and broadly ellipsoid to subglobose, truncate, weakly dextrinoid, cyanophilous basidiospores, measuring 4.9–5.2 × 4–4.8 μm. Perenniporia subcorticola is characterised by resupinate basidiocarps, yellow pores with thick dissepiments, tissues becoming dark in KOH, flexuous skeletal hyphae, ellipsoid, truncate and slightly dextrinoid basidiospores, measuring 4.2–5 × 3.5–4.2 µm. The morphologically-similar species and phylogenetically closely-related species to the two new species are discussed.

APA, Harvard, Vancouver, ISO, and other styles

12

Puari, Aninda Tifani. "Laboratory solid waste from practical activity as activated carbon precursor for reducing methylene blue in the laboratory wastewater." Jurnal Temapela 3, no. 2 (May 31, 2021): 73–79. http://dx.doi.org/10.25077/temapela.3.2.73-79.2020.

Full text

Abstract:

Activated carbon (AC) from agricultural waste has become one promising way to produce AC regarding to low price of the precursor and its effect to environment. In this research, the solid waste from the basic biology practical in UPT. Basic and Central Laboratory, Andalas University (Unand) was utilized as the precursor for producing low price AC. The activation was done by chemical activation using three different activating agents which were zink chloride (ZnCl2), phosphoric acid (H3PO4), potassium hydroxide (KOH). The carbonization process was done at temperature of 700°C. The precursor and three different AC after activation were characterized using fourier-transform infrared spectroscopy (FT-IR) to examine the functional group and scanning electron microscope (SEM) to observe the pores structure. The adsorption efficiency (AE) of each AC on methylene blue (MB) contained in laboratory wastewater was examined through adsorption process with retention time of 30 minutes at room temperature and neutral pH. SEM analysis showed that the three activating agents were resulting in higher surface area and more pores were formed. The highest AE of MB from laboratory wastewater for each AC were 97,5 %, 96,31%, and 90,79 for KOH, , ZnCl2, and H3PO4, respectively. Meanwhile, the highest adsorption capacity was achieved by AC through KOH activation with 0,003 mg/g

APA, Harvard, Vancouver, ISO, and other styles

13

Wu, Shuilin, Guanxiong Chen, Na Yeon Kim, Kun Ni, Wencong Zeng, Yuan Zhao, Zhuchen Tao, Hengxing Ji, Zonghoon Lee, and Yanwu Zhu. "Creating Pores on Graphene Platelets by Low-Temperature KOH Activation for Enhanced Electrochemical Performance." Small 12, no. 17 (March 8, 2016): 2376–84. http://dx.doi.org/10.1002/smll.201503855.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Kwiatkowski, Lech, Anna Kapuścińska, Alicja Bałkowiec, and Rafał Lutze. "Increasing the Surface Functionality of Mg Alloys by Means of Plasma Electrolytic Oxidation." Solid State Phenomena 227 (January 2015): 495–98. http://dx.doi.org/10.4028/www.scientific.net/ssp.227.495.

Full text

Abstract:

The aim of this work which is a part of larger approach, is the surface functionalization by means of plasma electrolytic oxidation (PEO) as a pretreatment prior to the application of biopolymer. The process was developed for the number of magnesium alloys, and AZ31, RZ5 and ZM21 in particular. An oxide layer was formed in two step consecutive process in KOH-Na3PO4 and KOH-NaF solutions. The coatings are built from sub-layers: reach in F at the metal-coating interface containing small pores and top layer with larger pores. An important feature for the surface biocompatibility is a presence and distribution of P within the top part of the coating which create a nucleation sites for the development of calcium phosphates. From the results of long term impedance measurements carried out in simulated body solution (SBF) at 37°C it may be concluded that the best corrosion protection is provided by the anodic layer formed on AZ31 alloy. After the testing the surface of alloys studied in this work was covered by a film of compounds containing calcium and phosphorus.

APA, Harvard, Vancouver, ISO, and other styles

15

Yao, Yong Zhao, Yukari Ishikawa, Yoshihiro Sugawara, and Koji Sato. "Removal of Mechanical-Polishing-Induced Surface Damages on 4H-SiC Wafers by Using Chemical Etching with Molten KCl+KOH." Materials Science Forum 778-780 (February 2014): 746–49. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.746.

Full text

Abstract:

High temperature (>1000 °C) chemical etching using molten KCl or molten KCl+KOH as the etchant has been carried out to remove the mechanical-polishing (MP) induced damage layer from 4H-SiC surface. Atomic force microscopy observations have shown that line-shaped surface scratches that have appeared on the as-MPed surface could be completely removed by KCl-only etching or by KCl+KOH etching (KCl:KOH=99:1 in weight) at ~1100 °C. Between the two recipes, KCl+KOH etching has shown a higher etch rate (6~7 times) and is able to remove ~9 μm and ~36 μm-thick damage layer from the Si (0001) and the C(000-1) surface, respectively. Besides, KCl+KOH etching seems to have formed a Si (0001) surface covered with atomic steps while KCl-only etched surface is featured with nanometer-scale pores.

APA, Harvard, Vancouver, ISO, and other styles

16

Kartikasari, Nurlisa, Rakhmawati Farma, and Awitdrus Awitdrus. "PENGARUH AKTIVASI KIMIA DENGAN BANTUAN IRADIASI GELOMBANG MIKRO TERHADAP SIFAT FISIS KARBON AKTIF DARI SEKAM PADI SEBAGAI ADSORBEN." Komunikasi Fisika Indonesia 15, no. 1 (April 30, 2018): 71. http://dx.doi.org/10.31258/jkfi.15.1.71-76.

Full text

Abstract:

The percentage of KOH affects the quality of activated carbon. In this research the activated carbon has been made of biomass from rice husk by using the process carbonization, chemical activation using Potassium Hydroxide variated percentage for 5%, 10%, 15% and 20% from the mass of sample and microwave irradiation power by 450 Watt. The surface morphology of activated carbon for the sample KA10 produced the even pores structure and lots of pores more than sample KA5, KA15 and KA20. The analysis results of surface morphology of activated also supported by analysis atomic adsorption spectroscopy (AAS) show that sample KA10 has the highest heavy metal adsorption 92,40% for Ni, 91,31% for Pb and 70,24% for Zn.

APA, Harvard, Vancouver, ISO, and other styles

17

Yuningsih, Lela Mukmilah, Dikdik Mulyadi, and A. Jaka Kurnia. "Pengaruh Aktivasi Arang Aktif dari Tongkol Jagung dan Tempurung Kelapa Terhadap Luas Permukaan dan Daya Jerap Iodin." Jurnal Kimia VALENSI 2, no. 1 (May 31, 2016): 30–34. http://dx.doi.org/10.15408/jkv.v2i1.3091.

Full text

Abstract:

The activated charcoal can be produced from various raw material which contains carbon such as corn cobs and coconut shell. Generally, activated charcoal made through activation process with added chemical materials. The kind of activator will give different influence on surface area or pores volume of the result activated charcoal. In this study, will be made activated charcoal from corn cobs and activated by physical and chemical with KOH activator. Carbonation process is performed at 800oC for 2 hours and followed by chemical activation process by KOH with mass ratio water: charcoal: KOH is 1:1:4, then activated by physical at 600oC for 4 hours. Conducted test on sample contain iodine adsorption and SEM. As a result, iodine adsorption of activated charcoal indicated at KOH 20%. the best adsorption of coconut shell activated charcoal is 1240.233 mg/g with surface area 2352.851 m2/g, while corn cobs activated charcoal is 1133.757 mg/g with surface area 2150.866 m2/g. Morphology of activated charcoal with KOH 20% have pore structure with high 22.63 µm and wide 26.41 µm, the resulting pore size included into macropores structure. Keywords: Activated charcoal, carbonation, activation, adsorption, surface area. DOI: http://dx.doi.org/10.15408/jkv.v2i1.3091

APA, Harvard, Vancouver, ISO, and other styles

18

Putra Parmita, Ade Wahyu Yusariarta, Andromeda Dwi Laksono, Muhammad Iskandar Zulkarnain, Ansita Fitri Budi Hartanti, and Rizky Vi'atul Mudhawammah. "Karakteristik Buah Nipah Karbon Aktif dari Serabut Nipah Teraktivasi Potassium Hydroxide (KOH)." SPECTA Journal of Technology 4, no. 3 (December 4, 2020): 72–79. http://dx.doi.org/10.35718/specta.v4i3.232.

Full text

Abstract:

Karbon aktif yang bersumber dari serabut buah nipah yang merupakan limbah yang belum dimanfaatkan dengan maksimal dibuat menggunakan metode aktivasi secara kimia menggunakan potassium hydroxide (KOH). Proses pembuatan karbon aktif dimulai dengan proses karbonisasi dilakukan dengan temperatur 400oC kemudian diaktivasi dengan kosentrasi KOH 1,5M. Hasil aktivasi KOH dibandingkan dengan hasil dari karbonisasi. Diperoleh hasil secara FTIR yang menunjukkan masih terdapat gugus fungsi yang menunjuukan adanya lignoselulosa dan sudah terbentuk grafit. Hasil XRD juga menunjuukan terbentuknya graphite amorph pada hasil aktivasi dengan KOH sedangkan hasil karbonisasi menghasilkan grafit yang lebih kristalin. Hasil XRD juga menunjukkan pada aktifasi KOH sudah tidak ada pengotor yang mengindikasikan proses adsorpsi yang lebih baik dibandingkan tanpa aktivasi. Hasil morfologi menunjukkan ukuran poros pada karbon yang teraktivasi KOH lebih besar 8,8 % dari pada tanpa aktivasi secara kimia. Ukuran pori yang lebih besar akan mengindikasikan luas permukaan yang lebih luas, sehingga akan lebih baik digunakan sebagai adsorben.

APA, Harvard, Vancouver, ISO, and other styles

19

LIU, GUO-HUA, XIAO-HONG JI, YONG-PING WANG, and JIA-JIA CHEN. "A new species of Fulvifomes (Basidiomycota) from China." Phytotaxa 470, no. 2 (November 3, 2020): 194–202. http://dx.doi.org/10.11646/phytotaxa.470.2.8.

Full text

Abstract:

Fulvifomes submerrillii (Hymenochaetaceae, Basidiomycota) is described from China based on both of morphological evidence and molecular data. The new species is characterized by perennial, pileate basidiocarps, encrusted, smooth pileal surface, 6–7 pores per mm with thick dissepiments, a dimitic hyphal system with interwoven skeletal hyphae, absence of setae or setal hyphae, ventricose cystidioles, and broadly ellipsoid, yellowish brown, thick-walled, smooth basidiospores, 4.7–5 × 3.7–4 μm. Phylogenetic analysis inferred from ITS and nLSU sequences indicates that the new species forms a separate well-supported clade, closely related to F. merrillii. However, F. merrillii has larger pores (4–5 per mm), a subdimitic hyphal structure in context, the contextual skeletal hyphae which regularly arranged and become swollen in KOH, and slightly longer (4.5–6 μm long) basidiospores. Moreover, one new combination (F. rigidus) is revived from synonym under Inonotus rigidus.

APA, Harvard, Vancouver, ISO, and other styles

20

BIAN, LU-SEN, CHANG-LIN ZHAO, and FANG WU. "A new species of Skeletocutis (Polyporales, Basidiomycota) from Yunnan of China." Phytotaxa 270, no. 4 (August 24, 2016): 267. http://dx.doi.org/10.11646/phytotaxa.270.4.3.

Full text

Abstract:

A new species of Polyporales, named as Skeletocutis yunnanensis, was collected on angiosperm wood in northern Yunnan Province, southwestern China. It is described based on morphological characteristics and molecular evidence. The species belongs to the Skeletocutis subincarnata complex, but differs morphologically from all known species of the genus by white, cream to buff pores surface, angular pores mostly 5–6 per mm with entire mouths, a dimitic hyphal structure both in trama and subiculum, generative hyphae in whole basidiocarps covered by fine crystals, skeletal hyphae unchanged in KOH, not agglutinated, allantoid basidiospores measured as 3.5–4.5 × 1.0–1.2 µm, and growth on angiosperm wood. Phylogenetic analysis based on the internal transcribed spacer (ITS) regions and nuclear large subunit (nLSU) ribosomal RNA gene regions indicated that the new species grouped with Skeletocutis and nested in the tyromyces clade.

APA, Harvard, Vancouver, ISO, and other styles

21

Sharon, Maheshwar, Ritesh Vishwakarma, Abhijeet Rajendra Phatak, Golap Kalita, Nallin Sharma, and Madhuri Sharon. "Microwave wide band absorption by carbon from Corn cob-1." JOURNAL OF ADVANCES IN PHYSICS 12, no. 2 (August 30, 2016): 4204–12. http://dx.doi.org/10.24297/jap.v12i2.53.

Full text

Abstract:

Corn cob, an agricultural waste, is paralyzed at different temperatures (700oC, 800oC and 900oC). Microwave absorption of carbon in the frequency range of 2 GHz to 8 GHz is reported. Carbon activated Â with 5%Â nickel nitrate showed more than 90% absorption of microwave in the frequency range from 6 GHz to 8 GHz, while carbon activated Â with 10% Nickel nitrate treated corn cob showed 90% absorptionÂ in the frequency range of 2.5 GHz to 5 GHz. Carbon showing the best absorption are characterized by XRD, Raman spectra and SEM . It is suggested that corn cob treatmentÂ Â alone with KOH did not improve the microwave absorption, whereas treatment along with nickel nitrate improved the absorption property much better. It is proposed that treatment with nickel nitrate helps in creating suitable pores in carbonÂ Â which improved the absorption behavior because while treating carbon with 1N HCl helps to leach out nickel creating equivalent amount of pores in the carbon.

APA, Harvard, Vancouver, ISO, and other styles

22

Park, Jong-Hyeok, and Jin-Soo Park. "KOH-doped Porous Polybenzimidazole Membranes for Solid Alkaline Fuel Cells." Energies 13, no. 3 (January 21, 2020): 525. http://dx.doi.org/10.3390/en13030525.

Full text

Abstract:

In this study the preparation and properties of potassium hydroxide-doped meta-polybenzimidazole membranes with 20–30 μm thickness are reported as anion conducting polymer electrolyte for application in fuel cells. Dibutyl phthalate as porogen forms an asymmetrically porous structure of membranes along thickness direction. One side of the membranes has a dense skin layer surface with 1.5–15 μm and the other side of the membranes has a porous one. It demonstrated that ion conductivity of the potassium hydroxide-doped porous membrane with the porogen content of 47 wt.% (0.090 S cm−1), is 1.4 times higher than the potassium hydroxide-doped dense membrane (0.065 S cm−1). This is because the porous membrane allows 1.4 times higher potassium hydroxide uptake than dense membranes. Tensile strength and elongation studies confirm that doping by simply immersing membranes in potassium hydroxide solutions was sufficient to fill in the inner pores. The membrane-electrode assembly using the asymmetrically porous membrane with 1.4 times higher ionic conductivity than the dense non-doped polybenzimidazole (mPBI) membrane showed 1.25 times higher peak power density.

APA, Harvard, Vancouver, ISO, and other styles

23

Guan, Yuming, Jingbo Mu, Hongwei Che, Xiaoliang Zhang, and Zhixiao Zhang. "Preparation of hierarchical porous carbon with high capacitance." World Journal of Engineering 15, no. 3 (June 11, 2018): 323–29. http://dx.doi.org/10.1108/wje-05-2017-0110.

Full text

Abstract:

Purpose The purpose of this study is to design carbon electrode materials for high performance electric double-layer capacitors (EDLCs) with pores that are large enough and have suitable pore size distribution for the electrolyte to access completely to improve EDLCs’ electrochemical performance. Design/methodology/approach This study develop an improved traditional KOH activation method, and a series of micro-meso hierarchical porous carbons have been successfully prepared from phenol formaldehyde resin by combining polyethylene glycol (PEG) and conventional KOH activation. Findings As evidenced by N2 adsorption/desorption tests, the obtained samples present Types IV and I-IV hybrid shape isotherms compared with KOH-activated resin (typical of Type I). The sample AC2-7-1, which the addition quantity of PEG is 25 per cent PF (weight ration) activated at 700? For 1 h is considered as the optimum preparation condition. It exhibits the highest specific capacitance value of 240 F/g in 30 wt% KOH aqueous electrolytes because of its higher specific surface area (2085 m2/g), greater pore volume (1.08 cm3/g) and the maximum mesoporosity (43 per cent). In addition, the capacity decay of this material is only 3.1 per cent after 1000 cycles. Originality/value The materials that are rich in micropores and mesopores show great potential in EDLC capacitors, particularly for applications where high power output and good high-frequency capacitive performances are required.

APA, Harvard, Vancouver, ISO, and other styles

24

Alcaraz, Lorena, María Esther Escudero, Francisco José Alguacil, Irene Llorente, Ana Urbieta, Paloma Fernández, and Félix Antonio López. "Dysprosium Removal from Water Using Active Carbons Obtained from Spent Coffee Ground." Nanomaterials 9, no. 10 (September 25, 2019): 1372. http://dx.doi.org/10.3390/nano9101372.

Full text

Abstract:

This paper describes the physicochemical study of the adsorption of dysprosium (Dy3+) in aqueous solution onto two types of activated carbons synthesized from spent coffee ground. Potassium hydroxide (KOH)-activated carbon is a microporous material with a specific Brunauer–Emmett–Teller (BET) surface area of 2330 m2·g−1 and pores with a diameter of 3.2 nm. Carbon activated with water vapor and N2 is a solid mesoporous, with pores of 5.7 nm in diameter and a specific surface of 982 m2·g−1. A significant dependence of the adsorption capacity on the solution pH was found, but it does not significantly depend on the dysprosium concentration nor on the temperature. A maximum adsorption capacity of 31.26 mg·g−1 and 33.52 mg·g−1 for the chemically and physically activated carbons, respectively, were found. In both cases, the results obtained from adsorption isotherms and kinetic study were better a fit to the Langmuir model and pseudo-second-order kinetics. In addition, thermodynamic results indicate that dysprosium adsorption onto both activated carbons is an exothermic, spontaneous, and favorable process.

APA, Harvard, Vancouver, ISO, and other styles

25

Zhang, Rui, Xiao Jia Duan, Quan Gui Guo, Bei Zhou, Xi Miao Liu, Ming Lin Jin, and Li Cheng Ling. "Effects of Ash Contents of Activated Carbon on the Performance of Electric Double Layer Capacitors." Advanced Materials Research 287-290 (July 2011): 1469–76. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1469.

Full text

Abstract:

High surface area activated carbon (AC) obtained by KOH activation of petroleum coke was leached by HCl aqueous solution and the effects of the ash contents of AC on performance of electric double layer capacitors (ECs) in 3M KOH aqueous electrolyte and 1 M (C2H5)4NBF4/propylene carbonate electrolyte were investigated by cyclic chronopotentiograms and electrochemical impedance spectrometry (EIS). An equivalent circuit model based on a mixed kinetic and charge transfer control was proposed to fit EIS spectra. The model parameters were extracted by Marquardt best fitting. The series solution resistances, polarization resistance and diffusion coefficient related to Warburg impedances were obtained. It is found that the series solution resistances remained constant, polarization resistances decreased and the diffusion coefficients increased after acid leaching for each electrolyte, indicating that acid leaching can remove the electronic inert ash, which decreases contact resistance among particles of activated carbon and opens or widens the blocked pores by ash components. Moreover, the specific capacitances of AC were increased by the acid leaching.

APA, Harvard, Vancouver, ISO, and other styles

26

Li, Xiya, Jieqiong Qiu, Yiqi Hu, Xiaoyuan Ren, Lu He, Nannan Zhao, Ting Ye, and Xueqin Zhao. "Characterization and comparison of walnut shells-based activated carbons and their adsorptive properties." Adsorption Science & Technology 38, no. 9-10 (September 10, 2020): 450–63. http://dx.doi.org/10.1177/0263617420946524.

Full text

Abstract:

The production of low-cost biologically activated carbons (BACs) is urgent need of environmental protection and ecological sustainability. Hence, walnut shells were treated by traditional pyrolysis, direct KOH impregnation and combined activation composed of hydrothermal carbonization and two-step H3PO4- and pyrolysis-activation process to obtain porous carbon with high adsorption capacity. It was found that the best adsorption capacity for iodine and organic dye methylene blue (MB) can be obtained using the KOH impregnation at impregnation ratio of 1:1 or combined activation comprising of 2 h H3PO4 activation and 1 h pyrolysis activation at 1000°C. The produced KOH, H3PO4/pyrolysis activated BACs at the optimum conditions are superior to that of commercial ACs, 9.4 and 1.3 times for MB removal, 4 and 4.5 times for iodine number respectively. Characterization results demonstrated their porous structure with very good textural properties such as high BET surface area (1689.1 m2/g, 1545.3 m2/g) and high total pore volume (0.94 cm3/g, 0.96 cm3/g). The N2 adsorption-desorption isotherm of H3PO4/pyrolysis activated hydrochar suggested the co-existence of micro and meso-pores. Moreover, they are more effective for the removal of Fe(III) and Cr(VI) from aqueous solution than the commercial AC, suggesting a promising application in the field of water treatment.

APA, Harvard, Vancouver, ISO, and other styles

27

Farma, Rakhmawati. "Physical Properties Analysis of Activated Carbon from Oil Palm Empty Fruit Bunch Fiber on Methylene Blue Adsorption." Journal of Technomaterials Physics 1, no. 1 (February 28, 2019): 67–73. http://dx.doi.org/10.32734/jotp.v1i1.824.

Full text

Abstract:

The present research was conducted to analyze the physical properties of activated carbon from oil palm empty fruit bunch fiber (OPEFBF) to be applied as methylene blue adsorbent material. The OPEFBF was pre-carbonized at 280oC for 4 hours in vacuum, milled, and sieved to obtain the self-adhesive carbon grain (SACG) with a size less than 106 µm. The chemical activation was done using potassium hydroxide (KOH) with variations of 25%, 50%, and 75% from the SACG weight, stirred at 400 rpm for 24 hours at room temperature and pyrolyzed using microwave irradiations at the output power of 720 W for 15 minutes. The physical properties of activated carbon consist of two characterizations, namely microstructure evaluated with X-ray diffraction (XRD) and surface morphology evaluated with scanning electron microscopy (SEM). The XRD pattern showed that the activated carbon had a semi-crystalline structure characterized by the presence of (002) and (100) planes at the diffraction angle of 2θ about 21o and 43o, respectively. The surface morphology of activated carbon depicted that a higher percentage of KOH resulted in more pores were formed. Thus, the higher the surface area of activated carbon, the greater the adsorption of methylene blue. The highest methylene blue adsorption was obtained in the sample of 75% KOH with 87.73 mg/g. The energy dispersive X-ray showed that the increase of KOH percentage used enhanced the percentage of carbon element produced.

APA, Harvard, Vancouver, ISO, and other styles

28

Nishinaka, K., S. A. Salman, K. Kuroda, and M. Okido. "Characterization and Structure Analysis of the Anodic Film Formed on AZ31 Mg Alloy in KOH Alkaline Solution with Various Additives." Key Engineering Materials 786 (October 2018): 159–64. http://dx.doi.org/10.4028/www.scientific.net/kem.786.159.

Full text

Abstract:

AZ31B Mg alloy was anodized under the current density of 20 mA cm-2 for 3.6 ks in KOH alkaline solutions contains 0.60 M KF, 0.09 M Na3PO4.12H2O, 0.45 M Al (OH)3and 0.13 M KMnO4at 298 °C. Pores structure anodic film was formed on magnesium alloy surface; the pours structure was also observed in the lower part of the anodic film. The anodic film consisted of MgO and MgAl2O4. The anodized film showed higher pitting potential from anodic polarization measurement in 0.1 M NaCl solution compared to non-anodized magnesium alloy specimen and leads to improve the corrosion resistance of anodized AZ31 magnesium alloy.

APA, Harvard, Vancouver, ISO, and other styles

29

Jia, Hong Min, Yan Hui Wang, and Guo Zhong Xu. "Study on Optimization of Activated Carbon Preparation Process Based on Apricot Shell." Advanced Materials Research 785-786 (September 2013): 739–44. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.739.

Full text

Abstract:

Activated carbon is a kind of material with many pores and large specific surface. Activated carbon has been widely applied in many fields for its excellent adsorption and steady chemical characters. Activated carbon was prepared with apricot shell as raw materials by the sequence of crushing, screening, carbonization and activation. To improve adsorption ability of activated carbon, KOH was added as a activator into the carbonization materials. The effect of carbonization and activation conditions on benzene value and Vitamin B12 value were investigated. Benzene value and Vitamin B12 value of activated carbon were improved from 163.01mg.g-1 and 19.16mg.g-1 to 589.14mg.g-1 and 35.02mg.g-1, respectively.

APA, Harvard, Vancouver, ISO, and other styles

30

Chakraborty, Dyutiparna, Alfredo Vizzini, and Kanad Das. "Two new species and one new record of the genus Tylopilus (Boletaceae) from Indian Himalaya with morphological details and phylogenetic estimations." MycoKeys 33 (April 13, 2018): 103–24. http://dx.doi.org/10.3897/mycokeys.33.23703.

Full text

Abstract:

Tylopilushimalayanus and T.pseudoballoui are described as new species from two Himalayan states (Sikkim and Uttarakhand) in India. Tylopilushimalayanus is characterised by a unique combination of features: reddish- or brownish-grey to purplish-grey then brown to reddish-brown or darker pileus, absence of olive or violet tinges on stipe surface, angular pores, stipe without reticulum or rarely with a faint reticulum restricted to the very apex, bitter taste of the context and positive macrochemical colour reaction of the stipe context with KOH (dark orange) and FeSO4 (dark green), medium sized (10.9–14.4 × 3.9–4.9 µm) basidiospores and occurrence under coniferous trees; T.pseudoballoui is distinguished by orange-yellow to brown-yellow sticky pileus, pale yellow pore surface with pinkish hues that turns pale to greyish-orange on bruising; angular pores, stipe concolorous to pileus with pruinose but never reticulate surface, ixocutis pattern of pileipellis and occurrence under broadleaf trees. Another species, T.neofelleus, which was reported earlier from China and Japan, was also collected from Sikkim and reported for the first time from India. All three species are described with morphological details and two-locus based (nrLSU and nrITS) phylogenetic data.

APA, Harvard, Vancouver, ISO, and other styles

31

Tippayasam, Chayanee, Phachongkit Boonanunwong, Jocelyn Calvez, Parjaree Thavorniti, Prinya Chindaprasirt, and Duangrudee Chaysuwan. "Effect of Porosity and Pore Size on Microstructures and Mechanical Properties of Metakaolin Blended with Ca(OH)₂ and PLA as Porous Geopolymers." Key Engineering Materials 690 (May 2016): 276–81. http://dx.doi.org/10.4028/www.scientific.net/kem.690.276.

Full text

Abstract:

Geopolymer is generally made of pozzolanic materials and alkali activators such as sodium alkali or potassium alkali. It can be solidified at ambient temperature to be developed as construction materials. Polylactic acid (PLA) was chosen to create pores in order for porous geopolymers. In this research, the porous geopolymer was developed either to reduce the weight of materials or to be utilized as thermal insulation materials. It was performed by metakaolin (MK), calcium hydroxide (Ca(OH)2), 10 molar potassium hydroxide (10M KOH) and potassium silicate (K2SiO3) for geopolymer pastes. These geopolymer pastes were mixed with 40 wt%, 50 wt% and 60 wt% of PLA and fired at 550°C for 6 h., therefore, pores inside geopolymer structure were found. Consequently, those geopolymers were characterized the mechanical properties e.g. compressive and flexural strength by Universal Testing Machine (UTM), microstructures by Scanning Electron Microscope (SEM), chemical compositions as functional groups by Fourier Infrared Spectroscope (FTIR). Furthermore, the pore size, bulk density, apparent porosity and thermal conductivity coefficient of geopolymers were analyzed. The results presented that the quantity of PLA affected the compressive strength and porosity of geopolymers. In conclusion, our porous geopolymer with 40 wt% PLA gave the highest strength.

APA, Harvard, Vancouver, ISO, and other styles

32

Hu, Fang Yuan, Si Yang Liu, Jin Yan Wang, Sheng Ming Li, and Xi Gao Jian. "Carbon Nanosheet Frameworks Derived from Pine Cone Shells as Sodium-Ion Battery Anodes." Materials Science Forum 956 (June 2019): 3–11. http://dx.doi.org/10.4028/www.scientific.net/msf.956.3.

Full text

Abstract:

As a kind of green, environment-friendly and sustainable carbon material, biomass carbon has simple processing technology and undoubtedly been the best candidate for industrialization. Different activation processes can be used to change the internal microstructure of carbons, and design pores that facilitate ions transport and electrons conduction, thereby achieving the ultimate goal of improving electrochemical performance. Herein, we select the same activator (KOH) and activation time (3 h) but change the activation temperature (300 °C, 600 °C, 800 °C) to obtain biomass-derived carbon with the different micromorphology, pores structure and heteroatoms content. Rather, We choose ether-based electrolyte, due to its highly reversible graphite co-intercalation reaction, the problem of extremely low electrochemical activity of graphite in ester electrolytes is avoided. Results indicate, the sample PCS-600 exhibites sheet structure with specific surface area of 38.3 m2/g and large average pore width of 2.77 nm, which providing sufficient conditions for ions transport. PCS-600 has 1.05 at% N and 5.75 at% O heteroatoms, which providing additional pseudocapacitance. In addition, the electrochemical performance of PCS-600 is optimal, at a current density of 0.1 A/g, its specific capacity is 198.6 mA h/g, maintain at ~95% after 100 cycles, with coulomb efficiency ~100%.

APA, Harvard, Vancouver, ISO, and other styles

33

Kandasamy, Ayshuwarya, Tamilselvi Ramasamy, Ayesha Samrin, Padmanathan Narayanasamy, Ramesh Mohan, Olha Bazaka, Igor Levchenko, Kateryna Bazaka, and Mandhakini Mohandas. "Hierarchical Doped Gelatin-Derived Carbon Aerogels: Three Levels of Porosity for Advanced Supercapacitors." Nanomaterials 10, no. 6 (June 17, 2020): 1178. http://dx.doi.org/10.3390/nano10061178.

Full text

Abstract:

Nitrogen-doped graphene-based aerogels with three levels of hierarchically organized pores were prepared via a simple environmentally friendly process, and successfully tested in supercapacitor applications. Mesopores and macropores were formed during the aerogel preparation followed by carbonization and its chemical activation by potassium hydroxide (KOH). These mesopores and macropores consist of amorphous carbon and a 3D graphene framework. Thermal treatment at 700 °C, 800 °C, 900 °C in N2 atmosphere was done to etch out the amorphous carbon and obtain a stable N-doped 3D graphene. Specific capacitance values obtained from the electrochemical measurements are in the range of 232–170 F× g−1. The thus fabricated structures showed excellent cyclic stability, suggesting that these materials have potential as electrodes for solid asymmetric supercapacitors.

APA, Harvard, Vancouver, ISO, and other styles

34

Ohimor, E. O., D. O. Temisa, and P. I. Ononiwu. "Production of Activated Carbon from Carbonaceous Agricultural Waste Material: Coconut Fibres." Nigerian Journal of Technology 40, no. 1 (March 23, 2021): 19–24. http://dx.doi.org/10.4314/njt.v40i1.4.

Full text

Abstract:

Activated carbon was produced from Cocos nucifera (coconut) fibers by carbonization and activation processes. The sample was first pretreated before carbonization and activation processes at 450°C and 700°C respectively in an electric furnace. Chemical activation using Potassium hydroxide (KOH) 4:1 (weight basis) was carried out to increase the activated carbon adsorption properties. The element contained in the sample was analyzed using the Energy Dispersive Spectroscopy (EDS) while the surface morphological composition was determined by Scanning Electron Microscope (SEM) and the chemical bonds present in the sample was characterized using Fourier transform infrared reflection (FT-IR). From the research carried out, the results show that activated carbon produced from coconut fibers would be useful and effective for adsorbent purposes, considering its large pores.

APA, Harvard, Vancouver, ISO, and other styles

35

Park, Joon Woo, Ki Yong Ann, and Chang-Geun Cho. "Resistance of Alkali-Activated Slag Concrete to Chloride-Induced Corrosion." Advances in Materials Science and Engineering 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/273101.

Full text

Abstract:

The corrosion resistance of steel in alkali-activated slag (AAS) mortar was evaluated by a monitoring of the galvanic current and half-cell potential with time against a chloride-contaminated environment. For chloride transport, rapid chloride penetration test was performed, and chloride binding capacity of AAS was evaluated at a given chloride. The mortar/paste specimens were manufactured with ground granulated blast-furnace slag, instead of Portland cement, and alkali activators were added in mixing water, including Ca(OH)2, KOH and NaOH, to activate hydration process. As a result, it was found that the corrosion behavior was strongly dependent on the type of alkali activator: the AAS containing the Ca(OH)2activator was the most passive in monitoring of the galvanic corrosion and half-cell potential, while KOH, and NaOH activators indicated a similar level of corrosion to Portland cement mortar (control). Despite a lower binding of chloride ions in the paste, the AAS had quite a higher resistance to chloride transport in rapid chloride penetration, presumably due to the lower level of capillary pores, which was ensured by the pore distribution of AAS mortar in mercury intrusion porosimetry.

APA, Harvard, Vancouver, ISO, and other styles

36

Shen, Yang, Luca Maurizi, Giuliana Magnacca, Vittorio Boffa, and Yuanzheng Yue. "Tuning Porosity of Reduced Graphene Oxide Membrane Materials by Alkali Activation." Nanomaterials 10, no. 11 (October 22, 2020): 2093. http://dx.doi.org/10.3390/nano10112093.

Full text

Abstract:

The alkali-activation method allows for obtaining highly porous carbon materials. In this study, we explored the effect of activation temperature and potassium hydroxide concentration on the pore structure of reduced graphene oxide (rGO), as potential membrane material. Above 700 °C, potassium species react with the carbon plane of rGO to form nanopores. This activation process is deeply studied through DSC measurements and isothermal gravimetric analysis. The porosity of the formed materials consists of both micro- and mesopores, with most of the pores having a size smaller than 10 nm. The specific surface area and pore volume increase with increasing the potassium hydroxide/graphene oxide weight ratio (KOH/GO) up to 7 (897 m2∙g−1 and 0.97 cm3∙g−1, respectively). However, for a synthesis mixture with KOH/GO of 10, the specific surface area of the produced material drops to 255 m2∙g−1. The film-forming ability of the porous reduced graphene oxide (PRGO) was tested by drop-casting on porous silicon carbide substrates. In this case, continuous PRGO films were obtained only from dispersions with 5 g∙L−1 GO loading and KOH/GO ≤3. Such films can still have high specific surface area and pore volume (up to 528 m2∙g−1 and 0.53 cm3∙g−1) and main pore volume <10 nm. Hence, they can potentially be applied as membrane devices, but their scalability and their adhesion on the substrate under realistic filtration conditions still remain challenges.

APA, Harvard, Vancouver, ISO, and other styles

37

Park, Joon Woo, Sung In Hong, Hee Jun Yang, Thamara Tofeti Lima, and Ki Yong Ann. "Cement-Free Mortar Using Ground Granulated Blast-Furnace Slag with Different Alkali-Activators." Applied Mechanics and Materials 578-579 (July 2014): 1430–40. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.1430.

Full text

Abstract:

The present study concerns a development of cement-free concrete using ground granulated blast-furnace slag (GGBS) with alkali-activators such as KOH, NaOH, and Ca (OH)2. To find out the development among three different activators, the concentration of hydroxyl ion was kept 0.5%, 1.0%, 1.5%, 2.0% and 3.0% by weight of binder irrespective of cations. The setting time was measured by penetration resistance immediately after casting of mortar. The development of compressive strength was measured at 7, 14, 28, and 91 days. The pore structure of cement-free mortar was examined by the mercury intrusion porosimetry (MIP) and rapid chloride penetration test (RCPT). Simultaneously, grew sample was used to microscopically observe at the XRD. For strength of cement-free mortar, mixed with KOH or NaOH was as high as OPC at 3.0 % by weight of binder. However, the compressive strength of cement-free concrete mixed with 3.0 % Ca (OH)2 by weight of binder had just half strength of OPC mortar. Cement-free concrete activated with NaOH and Ca (OH)2 had higher total pore volume, however, it had lower ionic penetrability due to the pore type which mostly consist of gel pores. For pore structure of cement-free mortar mixed with KOH, the total volume had similarity to that of OPC mortar, however, it had lower penetrability. Therefore, it may have higher resistance to chloride transport than that of OPC mortar.

APA, Harvard, Vancouver, ISO, and other styles

38

Deng, Jie, Jing Li, Shuang Song, Yanping Zhou, and Luming Li. "Electrolyte-Dependent Supercapacitor Performance on Nitrogen-Doped Porous Bio-Carbon from Gelatin." Nanomaterials 10, no. 2 (February 18, 2020): 353. http://dx.doi.org/10.3390/nano10020353.

Full text

Abstract:

The carbon supercapacitance strongly relies upon the electrolyte’s nature, but the clear-cut structure–performance nexus remains elusive. Herein, a series of bio-carbons with gradually varied pore structure and surface chemistry are derived using a new salt template protocol (with eco-benign KNO3 as the template, activator, and porogen, and cheap gelatin as the carbon precursor), and are used as model systems to probe the dependence of the electrochemical mechanism of such nanocarbons on two typical electrolytes (KOH and EMIBF4). By only adjusting the KNO3 dosage, two pivotal figures of merit of biochar—multiscale porosity and surface functionalization—were finely modulated to construct electric double layers. Electrochemical data clarify that the combined porosity and doping effects all contribute to enhanced supercapacitance, but with only one of the two factors playing the leading role in different electrolytes. Kinetic analysis corroborates the fact that ample heteroatom doping can effectively compensate capacitance by intensive surface redox insertion in KOH, while a suitable pore size dispersion plays a preponderant part in self-amplifying the ion partitioning, and thus dictating a good charge separation in EMIBF4. A quasi-quantitative model of performance–structure relevance in EMIBF4 is judiciously conjectured to hint at a superb ion–pore-size compatibility, in which the bi- and mono-layer ion confinement coupling in integrated single and double ion-sized pores is found to be more useful for curbing notorious over-screening effects and for changing the coordination number, Coulombic ordering, and phase conformation of EMIBF4 in several nm-sized nanopores. This unique energy storage fashion in ion-matching pores promotes the energy density of optimal samples to a novel level of 88.3 Wh kg−1 at 1 kW kg−1, which rivals the overwhelming majority of the reported carbon materials. In short, the comparison case study here reveals a valuable correlation of carbon’s figure of merit and electrolyte type, which may act as a vital rudder to design electrolyte-contingent state-of-the-art supercapacitor materials.

APA, Harvard, Vancouver, ISO, and other styles

39

Bleyen, Nele, Steven Smets, Wim Verwimp, Katrien Hendrix, Xavier Sillen, and Elie Valcke. "Hydration of Eurobitum bituminized waste under free swelling conditions: osmosis-induced swelling and NaNO3 leaching." MRS Advances 1, no. 62 (2016): 4103–8. http://dx.doi.org/10.1557/adv.2017.196.

Full text

Abstract:

ABSTRACTIn Belgium, Eurobitum bituminized radioactive waste is an important intermediate-level long-lived waste form that contains, besides bitumen and radionuclides, large amounts of soluble salts (mainly NaNO3). Geological disposal in a water-saturated sedimentary formation will induce swelling of Eurobitum due to water uptake by the hygroscopic salts embedded in a highly efficient semi-permeable bitumen membrane. Initially, while there is still free space in the primary waste containers, free swelling will occur. To improve our understanding of the water uptake processes under free swelling conditions, water uptake and leaching tests are being performed in which inactive Eurobitum was contacted at the top with 0.1 M KOH (simplified representation of young cement water) without effective stress on the sample. Under these test conditions, the evolution of the water uptake and NaNO3 leaching processes shows several stages: (1) initial fast ingress of water into and leaching of NaNO3 from pores close to the surface; (2) slower progression of the hydration front, the swelling and the leaching of NaNO3, but behaving linearly with the square root of time, indicating that these processes are controlled by diffusion; (3) after more than 2 to 3 years, the leaching, hydration and swelling rates re-increase, attributed to the formation of interconnecting pores and (micro)cracks in the bitumen matrix in response to its increasing deformation.

APA, Harvard, Vancouver, ISO, and other styles

40

Fomkin, Anatoly, Anatoly Pribylov, Ilya Men’shchikov, Andrey Shkolin, Oleg Aksyutin, Alexander Ishkov, Konstantin Romanov, and Elena Khozina. "Adsorption-Based Hydrogen Storage in Activated Carbons and Model Carbon Structures." Reactions 2, no. 3 (July 7, 2021): 209–26. http://dx.doi.org/10.3390/reactions2030014.

Full text

Abstract:

The experimental data on hydrogen adsorption on five nanoporous activated carbons (ACs) of various origins measured over the temperature range of 303–363 K and pressures up to 20 MPa were compared with the predictions of hydrogen density in the slit-like pores of model carbon structures calculated by the Dubinin theory of volume filling of micropores. The highest amount of adsorbed hydrogen was found for the AC sample (ACS) prepared from a polymer mixture by KOH thermochemical activation, characterized by a biporous structure: 11.0 mmol/g at 16 MPa and 303 K. The greatest volumetric capacity over the entire range of temperature and pressure was demonstrated by the densest carbon adsorbent prepared from silicon carbide. The calculations of hydrogen density in the slit-like model pores revealed that the optimal hydrogen storage depended on the pore size, temperature, and pressure. The hydrogen adsorption capacity of the model structures exceeded the US Department of Energy (DOE) target value of 6.5 wt.% starting from 200 K and 20 MPa, whereas the most efficient carbon adsorbent ACS could achieve 7.5 wt.% only at extremely low temperatures. The initial differential molar isosteric heats of hydrogen adsorption in the studied activated carbons were in the range of 2.8–14 kJ/mol and varied during adsorption in a manner specific for each adsorbent.

APA, Harvard, Vancouver, ISO, and other styles

41

Giraldo, Liliana, and Juan Carlos Moreno-Piraján. "Synthesis of Activated Carbon Mesoporous from Coffee Waste and Its Application in Adsorption Zinc and Mercury Ions from Aqueous Solution." E-Journal of Chemistry 9, no. 2 (2012): 938–48. http://dx.doi.org/10.1155/2012/120763.

Full text

Abstract:

We obtain activated carbons with high portion of meso pores using coffee residues as precursor for the application of adsorption of large adsorbates. Because of its natural properties, the coffee residue exhibited a large pore size. In this work, the coffee residue were impregnated with ZnCl2and KOH, and then carbonized under the nitrogen conditions and activated with CO2respectively. Obtained activated carbons are used in the adsorption of ions Hg(II) and Zn(II). These adsorbents are efficacious to remove these ions from aqueous solution, with monocomponent equilibrium adsorption capacities ranging from from 0.002 to 0.380 mmol∙g-1for Hg on ACK3 and from 0.002 to 0.330 mmol∙g-1for ACZ3. For Zn(II) on ACK2 from 0.002 to 0.300 mmol∙g-1, and from 0.001 to 0.274 mmol∙g-1for ACZ2.

APA, Harvard, Vancouver, ISO, and other styles

42

Lianto, Michael, Sulistiyawati Dewi Kiniasih, Irma Septi Ardiani, Malik Anjelh Baqiyah, and Vania Mitha Pratiwi. "Nanocarbon from Rice Straw as Supercapacitor Electrode." Materials Science Forum 964 (July 2019): 180–84. http://dx.doi.org/10.4028/www.scientific.net/msf.964.180.

Full text

Abstract:

Rice straw waste in Indonesia is abundant and not yet used optimally. The composition of rice straw is 40% cellulose, 30% hemicellulose, 15% silica and 15% lignin so it is potentially to be a raw material of active carbon and supercapasitor electrode. Many efforts has been done to increase the value of capacitance of electrode like increase the surface area with activation and milling process. In this research used the variation of activator substance and the variation of milling velocity, they are H3PO4 450 rpm, H3PO4 600 rpm, and KOH 450 rpm. The purposes of this research are identify and characterize the rice straw charcoal material as nanocarbon and also knowing the nanocarbon quality of rice straw charcoal material as supercapacitor electrode. The methods are carbonization, activation, and solid state reaction. The result of this research shows the value of capacitance at H3PO4 450 rpm, H3PO4 600 rpm, and KOH 450 rpm are 28,96 F/g; 30,89 F/g; dan 19,31 F/g. From this research, we can conclude that activator substance and milling velocity affect the value of capacitance that is produced. The result of SEM-EDX test is comparable with the result of cyclic voltammetry test, the higher number of pores the higher value of capacitances produced.

APA, Harvard, Vancouver, ISO, and other styles

43

Lee, Kuan-Ching, Mitchell Shyan Wei Lim, Zhong-Yun Hong, Siewhui Chong, Timm Joyce Tiong, Guan-Ting Pan, and Chao-Ming Huang. "Coconut Shell-Derived Activated Carbon for High-Performance Solid-State Supercapacitors." Energies 14, no. 15 (July 27, 2021): 4546. http://dx.doi.org/10.3390/en14154546.

Full text

Abstract:

Coconut shells, low-cost and renewable agro-wastes, were used as a starting material in the synthesis of hierarchical activated carbons via hydrothermal, KOH-activation, and carbonization techniques. The ratio of KOH to hydrochar was varied in a systemic manner to study how it influences the texture and electrochemical behavior of the capacitor. Coconut shell-based carbon coated on nickel foams presented a surface area of 1567 m2 g−1, with micropores as well as mesopores widely distributed. The sample showed superior electrochemical performance, attaining 449 F g−1 at 1 A g−1 in 6 M LiNO3 aqueous solution. The solid-state symmetric supercapacitor device delivered a specific capacitance of 88 F g−1 at 1 A g−1 and a high energy density of 48.9 Whkg−1 at a power density of 1 kW kg−1. At a wide voltage window of 2.0 V, the sample was highly stable during the cycle test, showing a 92% capacitance retention at 2 A g−1 after cycling for 5000 times. The superior performance is due to the sample possessing great BET surface area, a good distribution of pores, and the usage of a suitable electrolyte. This facilitates an electrical double layer that can be deployed for applications to store energy.

APA, Harvard, Vancouver, ISO, and other styles

44

Garba, Abdurrahman, Hatijah Basri, and Noor Shawal Nasri. "Preparation and Characterization of Green Porous Palm Shell Based Activated Carbon by Two Step Chemical Activation Using KOH." Applied Mechanics and Materials 773-774 (July 2015): 1127–32. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.1127.

Full text

Abstract:

The large quantity of agricultural waste materials that poses disposal challenge to our environment could be converted into useful products such as activated carbon (AC). Palm oil shell based porous AC was prepared by two step process using KOH as the chemical activant. Palm oil shell was carbonized at 800°C for 2 hours and activated using CO2 at same temperature for 1 hour which yield 23.27% fixed carbon. The AC was characterized by Langmuir surface area, BET surface area and pore volume of 410.7 m2/g, 350 m2/g and 0.2 cm3/g respectively, the FTIR analysis identified the presence of alkanes, carbonyls and hydroxyls as the main functional groups in the AC. Scanning electron microscopy images illustrates the gradual formation of pores from the precursor to the produced AC due to elimination of volatiles and contaminants in the material. However, the AC produced showed basic properties suitable for the removal of hydrophobic organic contaminants in water and wastewater.

APA, Harvard, Vancouver, ISO, and other styles

45

Peristiwady, Teguh, Wulan Koagouw, Jianguo Du, and Petrus Christianus Makatipu. "MEGANTHIAS KINGYO (KON, YOSHINO AND SAKURAI, 2000) (PERCIFORMES: SERRANIDAE) FROM BITUNG, NORTH SULAWESI, INDONESIA: FIRST RECORD FROM THE SOUTHWESTERN PACIFIC OCEAN." Marine Research in Indonesia 40, no. 2 (March 24, 2016): 41–47. http://dx.doi.org/10.14203/mri.v40i2.74.

Full text

Abstract:

Eight specimens of Meganthias kingyo were collected from Bitung, North Sulawesi, Indonesia between 2008 - 2010. The specimens were caught from about 70-150 m off Lembeh Island. M. kingyo differs from M. natalensis by having the following characteristics: pores lateral line scales (43 vs. 49); pectoral rays (16 vs. ii.14); body depth (47.1 vs. 51.9); head length (31.0 vs. 38.2), body depth (47.1 vs. 52.9), caudal peduncle depth (12.1 vs. 14.2), pectoral fin length (28.0 vs. 34.3), pelvic fin length (33.6 vs. 31.1), anal fin base length (19.4 vs. 22.2), caudal fin length (66.9 vs. 35.3) and longest dorsal fin ray (48.5 vs. 27.4). Previously, this species has been reported from Houzan-sone, off Miyako and Yaeyama Islands in Okinawa, Japan; and herein is recorded from off Lembeh Island, North Sulawesi, Indonesia.

APA, Harvard, Vancouver, ISO, and other styles

46

Popczyk, Magdalena, and B. Łosiewicz. "The Influence of Temperature of Electrodeposition on the Electrochemical Properties of Ni+MoS₂ Composite Coatings." Solid State Phenomena 228 (March 2015): 237–41. http://dx.doi.org/10.4028/www.scientific.net/ssp.228.237.

Full text

Abstract:

The Ni+MoS2composite coatings were prepared by electrodeposition under galvanostatic conditions from the Ni-plating bath containing suspended MoS2powder (100 mesh). Investigations of hydrogen evolution reaction (HER) were carried out using steady-state polarization measurements and electrochemical impedance spectroscopy (EIS) in 5 M KOH solution on the coatings obtained at 30, 40, and 50°C. It was found that the kinetics of the HER on the Ni+MoS2coatings decreases with the increase in the electrodeposition temperature of the coatings. This effect is attributed to decreasing content of MoS2(from 26.4 to 18.0 wt.%) embedded into the Ni matrix as composite crystalline component having the electrocatalytic properties towards the HER and/or surface development of the coatings. The higher amount of MoS2was embedded, the more porous electrodes containing pear-shape pores on the surface were produced what was detected by EIS.

APA, Harvard, Vancouver, ISO, and other styles

47

Lahrar, E. H., O. El Ghadraoui, A. Harrach, M. Zouhairi, T. Lamcharfi, and E. H. El Ghadraoui. "Influence of Strontium on the Structural and Dielectric Properties of Hydrothermally Processed PbTiO3 Ceramic." Asian Journal of Chemistry 32, no. 3 (January 31, 2020): 597–601. http://dx.doi.org/10.14233/ajchem.2020.22363.

Full text

Abstract:

Perovskite ceramic materials of the composition Pb1-xSrxTiO3 (PSxT) were prepared by hydrothermal process at a relatively low temperature. The solution of KOH favours the solubility of the precursors in solid state. Pressure and temperature are critical factors for the formation of pure perovskite PSxT phase. The reaction mixture in stoichiometric amount is put in an autoclave and treated at 180 ºC for 24 h. The powder obtained after grinding is treated at 400 ºC for 4 h. X-ray diffraction shows that the compounds crystallize in a pure phase of perovskite type. SEM morphology indicates a homogeneous microstructure of the grains with the presence of pores. The impedance spectroscopy study in the frequency range (1 KHz − 2 MHz) confirms the insertion of stronium into the lead titanate matrix and highlights the strontium effect on the transition temperature (Tc) and the value of dielectric permittivity (εr).

APA, Harvard, Vancouver, ISO, and other styles

48

Arie, Arenst Andreas, and Joong Kee Lee. "Preparation of Capacitor’s Electrode from Coconut Shell." Advanced Materials Research 875-877 (February 2014): 1585–89. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.1585.

Full text

Abstract:

Activated carbons were prepared from coconut shell by chemical activation method and utilized as electrode materials for electrochemical double layer capacitor (EDLC). A preliminary characteristic of activated carbon from coconut shell includes the Brunnaeur Emmett Teller (BET) analysis and cyclic voltammetry measurements. The BET surface area is not affected by the variation of activation temperature as both of the samples showed BET surface area of about 850-870 m2g-1. The N2 adsorption–desorption isotherms showed that the sample exhibited type I characteristics according to IUPAC classification, which confirms its micro-porosity. Compared with the un-activated carbon samples, the activated ones exhibited the better electrochemical properties with a specific capacitance of 150 F g−1 at a scan rate of 2 mV s−1. The good performance of activated carbon is attributed to the enhancement of surface area due to the KOH pretreatment which can open new pores accessible for the ionic transport

APA, Harvard, Vancouver, ISO, and other styles

49

LIU, ZHAN-BO, and YUAN YUAN. "Luteoporia citriniporia sp. nov. (Polyporales, Basidiomycota), evidenced by morphological characters and phylogenetic analysis." Phytotaxa 461, no. 1 (September 30, 2020): 31–39. http://dx.doi.org/10.11646/phytotaxa.461.1.4.

Full text

Abstract:

A new poroid wood-inhabiting fungus in the Polyporales, Luteoporia citriniporia sp. nov., is described from Sri Lanka based on morphological and molecular evidence. L. citriniporia is characterized by an annual growth habit; resupinate basidiocarps with lemon yellow pores when fresh becoming buff to clay pink upon drying, a distinct snow white and fimbriate sterile margin, tissues becoming pink in KOH, a monomitic hyphal system, generative hyphae thin- to distinctly thick-walled, usually encrusted with fine yellow crystals, and oblong-ellipsoid to subcylindrical basidiospores measuring 3.4–4.2 × 1.8–2.1 µm. The phylogenetic analysis based on ITS + nLSU rDNA sequences shows that the new species belongs to Luteoporia, forming a monophyletic lineage with strong support (100% BS, 100% BP, 1.00 BPP) and is closely related to L. albomarginata; the lineage groups with Crustodontia chrysocreas, Phlebiporia bubalina and Mycoacia uda. Both morphological and molecular characters confirm the placement of the new species in Luteoporia.

APA, Harvard, Vancouver, ISO, and other styles

50

Maconie, Robin. "CARE TO LISTEN: MILTON BABBITT AND INFORMATION SCIENCE IN THE 1950S." Tempo 65, no. 258 (October 2011): 20–36. http://dx.doi.org/10.1017/s0040298211000362.

Full text

Abstract:

Following Milton Babbitt's untimely death at the age of 94 (death at any age is untimely, since it unties the time dimension) in January 2011, I was interested in finding out more about his relationship, personal and music-theoretical, with the US information science community during and after the Eisenhower years. The musical avant-garde represented in parody by Babbitt and Cage as two poles of an antithesis sprang into life in the Cold War era at the same time as Scientology, MAD and Playboy magazine. Today the US doyen of priapism is ready to admit that even the best formula for a creative life has its natural limits. I wanted to ask Joseph Straus and Jerry Kohl what they thought of Babbitt's influence in the wider context of cognitive linguistics. In addition to positioning Babbitt as a significant influence on the Russian composer's serial music in the instructive Stravinsky's Late Music (Cambridge University Press, 2001), Joseph Straus is co-editor (with Stephen Dembski) of Babbitt's Words about Music. Jerome Kohl is a fellow Stockhausen enthusiast and distinguished former editor of Perspectives of New Music, a periodical set up in the 1960s to assert US authority in new musical theory and practice by an editorial board including Babbitt and graced by a logo in honour of serial music devised by Stravinsky himself.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Pores of Kohn'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles