Bibliografias temáticas / Acid-activated material

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Literatura científica selecionada sobre o tema "Acid-activated material"

Autor: Grafiati

Publicado: 14 de dezembro de 2024

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Artigos de revistas sobre o assunto "Acid-activated material"

Dai, Yi Min, Ru Bin Tan, Wen Min Shi, Zhen Fei Liang e Long Tan. "A Study on the Reduction of HCN in Cigarette Smoke by Loading Cuprous Oxide on the Surface of Activated Carbon". Advanced Materials Research 239-242 (maio de 2011): 306–9. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.306.

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Taking Cu(CH3COO)2·H2O and activated carbon (AC) which was treated by acid and alkali as raw materials. The polylol reduction method was then adopted to prepare the cuprous oxide and activated carbon composite material. The structure and morphology of composite material samples were characterized by BET, SEM and XRD. The effects of cuprous oxide and activated carbon composite material on reducing the hazards of hydrocyanic acid in the cigarette were studied. Different pretreatment methods and the effect of mixture ratio to drop focal relieving harm of hydrocyanic acid in the cigarette were examined.

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Wang, Kun, Qiao Wen Yang, Chuan Liu, Hui Zhao, Gan Chen e Shi Wei Wang. "Study of Deashing and Activation on the Coke Fines and Semi-Cokes Based on Properties of Composite Materials". Advanced Materials Research 600 (novembro de 2012): 178–81. http://dx.doi.org/10.4028/www.scientific.net/amr.600.178.

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Coke fines and semi-cokes have high ash content, low specific surface area and pore volume. In order to increase the properties of the sample and make the activated composite materials, it must be deashed and activated. In this research, the deashing experiment of the raw materials by different concentration of HNO3 and KOH was tested, then the material was activated in high temperature steam. From the FTIR test, we can acquire the content of the surface functional groups, such as carboxyl and hydroxyl. The specific surface area, pore size, volume of the material were determinated by using the N2 isothermal adsorption. From the experiments of acid and alkali treatment, we can conclude that the optimal technological condition of the material: the concentration 20% of alkali and acid treatment processing. The ash content is decreased to 8%. The acid functional groups increased rapidly after HNO3 treatment. The activated coke fines have mainly mesopores and its proportion of microspore is low. The specific surface area of the activated material reached 80m2/g and increased about 5 times than that of raw materials.

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Li, Ya Jie, Xing Yuan Ni, Jun Shen, Dong Liu e Nian Ping Liu. "Nitric Acid Activated Carbon Aerogels for Supercapacitors". Applied Mechanics and Materials 302 (fevereiro de 2013): 158–64. http://dx.doi.org/10.4028/www.scientific.net/amm.302.158.

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The electrochemical performances of resorcinol–formaldehyde-based carbon aerogels can be significantly enhanced by nitric acid activation.FT-IR spectra and SEM images reveal the constitution and morphology of samples .The electrochemical performances of materials were tested by cyclic voltammetry,galvanostatic charge/discharge test ,electrochemical impedance spectroscopy and cyclic test. The results show that activation does not influence the molecular structure of carbon aerogels,which maintains their nano-porous structure. Activation increases the specific capacitance by 50% and improves the conductivity of carbon aerogels,resulting in fenfect cycling stability. So nitric acid activated carbon aerogels is an ideal electrode material for supercapacitors.

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Goodwin, Vituruch, Thanathon Sesuk e Parinya Jitreewas. "Biobased Activated Carbon from Palm Biomass Enhancing with Acid Treatment as Supercapacitor Electrode Material". SIAM: Science and Innovation of Advanced Materials 4, n.º 1 (25 de junho de 2024): 67002. http://dx.doi.org/10.48048/siam.2024.67002.

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Current research on energy storage systems, batteries, and supercapacitor devices is aimed to enhance efficiency and improve environmental sustainability. Supercapacitors offer remarkable attributes such as high transient response and power density. Typically, supercapacitor electrode is made from highly porous carbon material, activated carbon. Commercial activated carbon could be produced from coal, peat, or coconut shell. This study focused on utilization of palm biomass, palm empty fruit bunch (EFB), as raw material to produce activated carbon electrode. The highly porous activated carbon from EFB was synthesized via a low-temperature hydrothermal process and chemical activation. The resulting EFB activated carbon demonstrates favorable characteristics in terms of elevated surface area and porosity. This research investigates the enhancement of activated carbon with acid treatment during hydrothermal process. Two types of acid, citric acid, and phosphoric acid, at different concentrations, were added to biomass. The acid-treated activated carbon from palm biomass was characterized for the specific surface area (BET), pore size distribution and pore volume using the N2 adsorption/desorption technique. The acid-treated activated carbon was fabricated into carbon electrodes and assembled in a symmetrical supercapacitor with 1M H2SO4 as an electrolyte. The supercapacitor performance of acid-treated activated carbon was tested in a symmetrical Swagelok cell to assess specific capacitance using cyclic voltammetry and galvanostatic charge-discharge methods. The acid-treated activated carbon has higher specific capacitance than the activated carbon without acid treatment. This superior performance is attributed to the reduced internal resistance as revealed by the Electrochemical Impedance Spectroscopy (EIS) result. This is possibly due to the formation of micropores in the range of 0.6−0.7 nm which is a suitable pore size for ion transportation in H2SO4 electrolytes. This research has shown that biobased activated carbon from palm oil biomass with acid treatment has a high potential to be used as supercapacitor electrode material. Keywords: Activated carbon, Palm biomass, Hydrothermal, Energy storage, Supercapacitor

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Kovalchuk, Oleksandr, e Victoriia Zozulynets. "STUDY OF ACID RESISTANCE OF HYBRID ALKALI ACTIVATED NORMAL HARDENING CEMENTS". Urban development and spatial planning, n.º 81 (31 de agosto de 2022): 189–98. http://dx.doi.org/10.32347/2076-815x.2022.81.189-198.

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One of the reason of loses of main production sources nowadays for chemical, food and special industries is the degradation of equipment and constructions caused by acid corrosion. Traditional materials are characterized by various disadvantages, among them: high costs of the material, low water resistance, hard technology and danger for the personal. One of the ways to obtain acid resistant material is the use of alkali activated cements, which are known are the resistant to the aggressive environments. Increasing of acid resistance is possible by reducing of system basicity level. The presented studies have proved the possibility to obtain acid resistant materials, able to be hardening in normal condition, so far as possibility to partial replacement of the conditional alumina silicates by alumina silicates with technogenic origin, namely, red mud from alumina production under Bayer process. Reducing of basicity level make it possible to increase corrosion resistance coefficient up to 0.88. Also thus a way material became more ecologically friendly and lowering the cost of material.

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Ayati, Bamdad, Darryl Newport, Hong Wong e Christopher Cheeseman. "Acid activated smectite clay as pozzolanic supplementary cementitious material". Cement and Concrete Research 162 (dezembro de 2022): 106969. http://dx.doi.org/10.1016/j.cemconres.2022.106969.

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Shrestha, Rajeshwar Man. "Characterization of Activated carbons Prepared from a Locally Available Material by Iodine Number". Journal of the Institute of Engineering 13, n.º 1 (22 de junho de 2018): 139–44. http://dx.doi.org/10.3126/jie.v13i1.20359.

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The adsorption of Iodine by the activated carbons prepared from a locally available material Lapsi Seed Stone has been studied. Various activated carbons were prepared by varying the parameters such as ratio of Lapsi Seed Stone particles to Phosphoric acid, percentage of phosphoric acid concentration, carbonization temperature and carbonization time. Determination of Iodine numbers of the activated carbons was done by the standard method. The effect of various preparation conditions on Iodine number of different activated carbons is also investigated. The optimum conditions for the preparation of activated carbon are found to be 400 ° C -the carbonization temperature, 4 hours - the carbonization time, 1:1- the ratio of Lapsi Seed Stone particles and Phosphoric acid and 50 %- the percentage of phosphoric acid concentration.Journal of the Institute of Engineering, 2017, 13(1): 139-144

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Tišler, Zdeněk, Kateřina Hrachovcová, Eliška Svobodová, Jan Šafář e Lenka Pelíšková. "Acid and Thermal Treatment of Alkali-Activated Zeolite Foams". Minerals 9, n.º 12 (20 de novembro de 2019): 719. http://dx.doi.org/10.3390/min9120719.

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The foamed alkali-activated zeolite materials have been studied primarily in terms of mechanical and structural properties as potential substitutes for concrete and other building materials. However, they also have interesting textural and acid properties that make them much more useful, especially in the chemical industry. The aim of the study is to map in detail the influence of post-synthesis modifications of alkali-activated natural zeolite foams on their chemical, mechanical, and textural properties for possible use in catalytic and adsorption applications. Alkali-activated natural zeolite foam pellets were prepared by activation with mixed potassium hydroxide and sodium silicate activator and foamed using H2O2 solution. The foam pellets were post-synthetic modified by leaching with mineral and organic acids and calcination. The properties of the modified materials were characterised on the basis of XRF, XRD, N2 physisorption, DRIFT, SEM, NH3-TPD analyses, and the strength measurements. Our data showed that the basic clinoptilolite structure remains unchanged in the material which is stable up to 600 °C after acid leaching. In two-step leaching, the specific surface area increases to 350 m2/g and the leaching process allows the acid properties of the materials to be varied.

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Joko Murtono e Iriany. "PEMBUATAN KARBON AKTIF DARI CANGKANG BUAH KARET DENGAN AKTIVATOR H3PO¬4 DAN APLIKASINYA SEBAGAI PENJERAP Pb(II)". Jurnal Teknik Kimia USU 6, n.º 1 (19 de maio de 2017): 43–48. http://dx.doi.org/10.32734/jtk.v6i1.1564.

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Activated carbon necessity in Indonesia was increasing along with the developments of the industriaization era. Based on natural product in Indonesia, probably activated carbon necessity could be guaranteed by domestic production. Rubber shells were solid waste which has potential for multiple uses such as raw materials for the manufacture of activated carbon. In this researched, rubber shells waste were processed into activated charcoal. The aim of this researhed was to determine the effect of the concentration of phosphoric acid activator toward the characteristics of the activated carbon and activated carbon absorption capacity to Pb(II). Shells rubber that passed by the of 100 mesh sieve was impregnated with phosphoric acid (H3PO4) as activator in the ratio fruit shells rubber: phosphoric acid (b:b) of 1:2 and varying concentrations of H3PO4 at 20%, 40%, and 60% for 1 hour. After immersion in the acid, then material was carbonized in a furnace at temperature 500 oC for 1 hour. Surface area of activated carbon was analyzed by usning Braunanear, Emmelt and Teller and concentration of adsorption of Pb(II) was measured by Atomic Absorption Spectroscopy. The results showed the general characteristics of activated carbon comparable to the Indonesian National Standard. The largest adsorption capasity percentage 74% is obtained using Rubber shell activated carbon that activated by 20% phosphoric acid .

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Park, Jung Eun, Gi Bbum Lee, Ho Kim e Bum Ui Hong. "High Surface Area–Activated Carbon Production from Cow Manure Controlled by Heat Treatment Conditions". Processes 10, n.º 7 (29 de junho de 2022): 1282. http://dx.doi.org/10.3390/pr10071282.

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In this study, methods of adding value to cow manure were studied. Due to the properties of cow manure, activated carbon with a high surface area can only be produced by increasing the fixed carbon ratio and removing the ash content. Activated carbon was fabricated using five different treatments: (1) raw material–chemical activation, (2) raw material–hydrothermal carbonization–chemical activation, (3) raw material–hydrothermal carbonization–chemical activation–acid washing, (4) raw material–hydrothermal carbonization–heat treatment–chemical activation, and (5) raw material–hydrothermal carbonization–chemical activation–acid washing. The products then underwent proximate, elementary, and surface area analyses. In addition, changes in activated carbon properties depending on the heat treatment temperature (300, 500, 700 °C) and the applied chemical activator ratios (1:1–1:3) were examined. The results showed that the best heat treatment temperature was 300 °C, and the cow manure to chemical activator ratio was 1:2. The heat treatment stabilization process increases the fixed carbon ratio and the solid yield, and the acid wash process removes substances that restrain the increase in surface area. Therefore, activated carbon with a surface area of 1955 m2/g can be produced after the addition of heat treatment and an acid wash to the process. In addition, the adsorption properties of activated carbon with different heat treatment conditions were studied.

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Mais fontes

Teses / dissertações sobre o assunto "Acid-activated material"

Robbins, Steven C. "Distribution of Colloidal Material in Activated Sludge as Influenced by Cations". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/45540.

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Activated sludge influent and effluent from five municipal wastewater treatment plants were analyzed to further elucidate the roles of aluminum, iron, and the monovalent to divalent cation ratio (M/D) on the influent and effluent characteristics of the systems. The size distribution of organic nitrogen, organic carbon, protein, humic acid, and polysaccharide was examined with respect to the concentration of cations in the activated sludge influent. It was found that the majority of organic nitrogen, organic carbon, protein and polysaccharides were found in material larger than 0.45Î¼m in activated sludge influent. Humic acids were mostly found in material smaller than 0.45Î¼m. Protein was the largest contributor to organic nitrogen and humic acids were the largest contributor to organic carbon. Using 0.45Î¼m as a division between particulate and soluble material, the ratio of soluble to particulate material in activated sludge influent was found to be negatively correlated with the ratio of iron to aluminum. In activated sludge effluent, the majority of the organic nitrogen and protein was found in material larger than 0.45Î¼m, while the majority of the organic carbon, humic acid, and polysaccharide were found in material smaller than 30kDa. Influent aluminum concentration had no observable effect on the concentration or distribution of organic nitrogen or organic carbon. Influent iron appeared to play a role in the flocculation of organic nitrogen and protein containing material between 0.45Î¼m and 1kDa in size. A high monovalent to divalent cation ratio appeared to play a role in deflocculating organic nitrogen containing material larger than 1.5Î¼m and increased the concentration of TOC smaller than 1kDa and the total polysaccharide concentration. Tertiary depth filtration removed all organic nitrogen and protein in material larger than 0.45Î¼m, but a poor job of removing organic carbon from and an inconsistent job of removing polysaccharide from effluent Eight lab-scale activated sludge reactors were also run, but the data was not consistent enough for analysis and comparison with the municipal wastewater treatment plants. This thesis contains a series of four papers that each deal with a different aspect of the role of cations on activated sludge influent and effluent. The first paper focuses on activated sludge influent characteristics, the second on effluent organic nitrogen and organic carbon, the third on effluent EPS, and the last on the lab-scale reactors. The papers were divided in this way because of the unique analytical obstacles that were encountered with each set of data.
Master of Science

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Yang, Qi. "Résistance au feu de géopolymère alcalin et de de géopolymère acide". Electronic Thesis or Diss., Centrale Lille Institut, 2024. http://www.theses.fr/2024CLIL0014.

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Cette étude concerne les propriétés de résistance au feu des géopolymères préparés paractivation alcaline ou acide. La première partie passe en revue l’état de l’art sur ledéveloppement des matériaux géopolymères, leur processus de synthèse, les méthodesd'activation, les méthodes d'application et l'influence de leurs composants sur leurspropriétés. Un accent particulier est mis sur leur propriétés de résistance au feu. Les travauxconcernent les facteurs influençant la résistance au feu des géopolymères activés par desalcalins, notamment le rapport Al/Si, et la nature de cations utilisés. Les résultats montrentque plus le rapport Al/Si est faible, plus le géopolymère se ramollit à haute température (≥100°C) et se dilate en raison de la pression interne crée par la vaporisation de l'eau. Comparésaux géopolymères à base de sodium, les géopolymères à base de potassium ont un degré depolymérisation plus faible pour un même temps de polymérisation. Même avec un faiblerapport Si/Al, des silicates à faible polymérisation peuvent se former et provoquer l'expansiondu géopolymère. En revanche, les géopolymères à base de sodium subissent une réaction depolymérisation plus complète, mais perdent leur capacité de ramollissement à hautetempérature (≥ 100°C) et sont sujets à la fissuration.Dans des conditions d'activation acide, les géopolymères présentent également une bonnerésistance au feu grâce à leurs propriétés d’intumescence lorsqu’ils sont soumis à une sourceexterne de chaleur, similaires aux géopolymères activés par des alcalins. Le principal facteurinfluençant cette propriété est le rapport P/Al. Lorsque le rapport P/Al est élevé (≥ 0.74), duphosphore peu condensé est générée lors de la polymérisation, qui se déshydrate et secondense lors du chauffage, provoquant le ramollissement et l'expansion du matériau. Enraison de cette caractéristique d'intumescence, les géopolymères à faible rapport Al/Si(géopolymère alcalin) ou à haut rapport P/Al (géopolymère acide) sont des matériauxrésistants au feu prometteurs
This work deals with the fire resistance properties of geopolymers alkali- or acid-activated.The first part deals with the state of the art of the development of geopolymer materials,including their synthesis process, activation methods, application scenarios, and the influenceof their components on properties. A particular focus is on their potential benefit as fire-resistant materials. The thesis reveals the superior fire resistance of alkaline geopolymers andinvestigate the factors affecting the fire resistance, including the Al/Si ratio, and type ofcations. The results evidence that the lower the Al/Si ratio, the more the geopolymer softensat high temperatures (≥ 100°C) and expands due to the driving force of water vaporization.Compared to sodium-based geopolymers, potassium-based geopolymers have a lower levelof polymerization for the same curing time. Even with a high Al/Si ratio, low-polymerizationsilicates can form and cause the geopolymer to expand at high temperatures. In contrast,sodium-based geopolymers undergo higher complete polymerization reactions but lose theirsoftening ability at high temperatures (≥ 100°C) and are prone to cracking.Similar to alkali-activated geopolymers, acid-activated geopolymers exhibit good fireresistance thanks to their intumescence characteristics upon heating. The main factorinfluencing such property is the P/Al ratio. When the P/Al ratio is high (≥ 0.74), a largeamount of slightly condensed phosphorus is generated, which dehydrates and condensesupon heating, causing the material to soften and expand. Due to this intumescencecharacteristic, geopolymers with low Al/Si (alkaline geopolymer) or high P/Al (acidicgeopolymer) are promising fire-resistant material

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Li, Zihui. "Acid Leaching Resistance and Alkali Silica Reaction (ASR) of Alkali-Activated Cement Free Binders". Thesis, Clarkson University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10640300.

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Recently, increased awareness of the significance of developing sustainable materials for construction has renewed the interest in exploring Alkali activated concrete (AAC), a concrete that contains no cement, but only industrial by-products such as fly ash and slag, as a low energy alternative to the conventional concrete. Although the feasibility of making alkali–activated concrete with acceptable strength and mechanical properties is well documented, the information regarding the long-term durability, including resistance to acid attack and alkali silica reaction (ASR), is far from comprehensive and there is a need to increase the understanding of these durability issues. In this dissertation, these durability issues are addressed, and improvements in this novel technology will increase acceptance in industry. This dissertation presents a comprehensive evaluation into the acid leaching resistance of Alkali-Activated Concrete (AAC) and Ordinary Portland Cement (OPC). The deterioration in AAC and OPC when exposed to different types of acid laden (organic and inorganic) environments are quantified by characterizing the strength degradation, mass change and visual appearances. The changes in microstructure development and chemical composition are examined and analyzed in order to determine the mechanism of deterioration. Additionally, the effect of the addition of nanoparticles on the mechanical properties and resistance to sulfuric leaching of Alkali Activated Slag concrete (AAS) are also explored in this study.

Furthermore, this dissertation summarizes the findings of an experimental evaluation of alkali silica reaction (ASR) in cement free alkali activated concrete (AAC). The susceptibility of AAC to deleterious ASR was evaluated in this study in accordance with relevant ASTM standards. This study also compares the resistance of AAC with ordinary portland cement concrete (OPC) while exposed to ASR under ASTM C 1293 and ASTM C1567 tests. In particular, the focus of this investigation is to assess the effectiveness of existing ASTM test methods in identifying the occurrence of ASR in alkali activated slag cement (AAS) concrete. In addition to that, influences of activator parameters including the effect of binder type, activator concentration, activator type and water content to the resistance of ASR in AAC were also evaluated. Finally, a scanning electron microscopic study coupled with EDX analyses was used to explain the mechanism of ASR occurrence in AAC and OPC.

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Pan, Chung-kai, e 潘仲凱. "Phosphoric Acid Activated Carbon Fabrics as Supercapacitor Materials". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/45371813364590711505.

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碩士
逢甲大學
材料科學所
94
Activated carbon fiber fabrics were prepared with oxidized PAN fiber precursor in which phosphoric acid is used as a chemical-activation agent, and co-activated with steam or carbon dioxide gas in various temperature, 700 to 1000℃. Due to the high specific surface area, ACFFs were often used as an electrode of the electric double-layer capacitor. The study was focused on the influence of different chemical activation method and the physical properties to the microstructures of ACFFs, and also the performances of the capacitance of the electric double-layer. The porous structure of ACFFs was created in the activation and the porous texture was influenced by different activation method technique which is depended on the activated agents. The experimental data shows that the micropores structure were created very fast in the early stage of activation, and then the porous structure will connected with each other to from supermicro- or meso-pores in the further activation gradually. There is a maximum specific surface area, 1087 m2/g, contributed from the micropore structure for the major porous system of ACFFs. When raising the activation temperature to 1000℃, a large amount of mesopores was created on ACFFs, and with 660 m2/g specific surface area for mesopore which was activated with steam agent. From cyclic voltammetry, there was a the maximum specific capacitance, 173 F/g, which the ACFFs electrode was activated at 900℃ with 829 m2/g. The result suggests that specific capacitance was not only dependent on specific surface area, but the porous texture.

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Morris, Eric Adde. "Modification of Carbonaceous Materials with Sulfur and Its Impact on Mercury Capture and Sorbent Regenertion". Thesis, 2012. http://hdl.handle.net/1807/36293.

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Physical activation of oil-sands fluid coke, a dense carbonaceous material, using sulfur dioxide (SO2) was investigated as a means of utilizing a plentiful and inexpensive waste for elemental mercury (Hg) removal. A new model was developed to elucidate physical activation of dense carbonaceous materials. Experiments and model simulations revealed that, during activation with SO2, a sulfur-rich porous layer is formed around the periphery of the coke particles; this porous layer reaches a maximum thickness as a result of diffusion limitations; the maximum porous layer thickness is controlled by activation conditions and determines the maximum achievable specific surface area (SSA). Pre-oxidation in air prior to activation, acid washing after activation and smaller coke particle size all result in higher SSA. The highest SSA achieved was 530 m2/g, the highest yet found for oil-sands fluid coke with physical activation. If present, oxygen out-competed SO2 for carbon during activation. SO2 activation and porous layer formation did not occur until oxygen was depleted. Sulfur added to coke through SO2 activation is mainly in reduced forms which are more thermally stable than elemental sulfur in commercial sulfur-impregnated activated carbons (SIACs). TGA and elemental analyses revealed that only 17% of sulfur was removed at 800°C from SO2-activated coke under inert conditions, compared with 100% from a commercial SIAC. The role of sulfuric acid (H2SO4) in vapor Hg capture by activated carbon (AC) was studied due to conflicting findings in the recent literature. In the absence of other oxidizing species, it was found that Hg could be oxidized by oxygen which enhanced vapor Hg adsorption by AC and Hg absorption in H2SO4 solution at room and elevated temperatures. At 200°C, AC treated with 20% H2SO4 reached a Hg loading of more than 500 mg/g, which is among the highest Hg capacities yet reported. When oxygen was not present, S6+ in H2SO4 was found to act as an oxidizer of Hg, thus enabling Hg uptake by H2SO4-treated AC at 200°C. Treating the AC with SO2 at 700°C improved the initial rate of Hg uptake, with and without subsequent H2SO4 treatment.

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Livros sobre o assunto "Acid-activated material"

Parker, Philip M. The 2007-2012 World Outlook for Treated Clays That Have Been Artificially Activated with Acid or Other Materials. ICON Group International, Inc., 2006.

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The 2006-2011 World Outlook for Treated Clays That Have Been Artificially Activated with Acid or Other Materials. Icon Group International, Inc., 2005.

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Capítulos de livros sobre o assunto "Acid-activated material"

Davoodabadi, Maliheh, Marco Liebscher, Massimo Sgarzi, Leif Riemenschneider, Daniel Wolf, Silke Hampel, Gianaurelio Cuniberti e Viktor Mechtcherine. "Electrical and Sulfate-Sensing Properties of Alkali-Activated Nanocomposites". In Lecture Notes in Civil Engineering, 285–96. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_29.

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AbstractWe investigated the formation of the conductive network of carbon nanotubes (CNTs) in alkali-activated nanocomposites for sulfate-sensing applications. The matrix was a one-part blend of fly ash and ground granulated blast-furnace slag, activated by sodium silicate and water. Sodium dodecylbenzenesulfonate was used as the surfactant for dispersion of the CNTs in the aqueous media. The nanocomposites were investigated by a laboratory-developed setup to study the electrical and sensing properties of the alkali-activated material. The electrical properties (i.e., conductivity) were calculated and assessed to discover the percolation threshold of the nanocomposites. Furthermore, the sensing behavior of nanocomposites was studied upon sulfate ($${\mathrm{SO}}_{4}^{2-}$$ SO 4 2 - ) exposure by introduction of sulfuric acid ($$({\mathrm{H}}_{2}{\mathrm{SO}}_{4})$$ ( H 2 SO 4 ) ) and magnesium sulfate ($${\mathrm{MgSO}}_{4}$$ MgSO 4 ). The sensors were able to preliminarily exhibit a signal difference based on the introduced media ($${\mathrm{H}}_{2}{\mathrm{SO}}_{4} \&\mathrm{ Mg}{\mathrm{SO}}_{4}$$ H 2 SO 4 & Mg SO 4 ), CNT content and $${\mathrm{H}}_{2}{\mathrm{SO}}_{4}$$ H 2 SO 4 volumetric quantity. The results of this research demonstrated a sensing potential of CNT alkali-activated nanocomposites and can be applied in the concrete structural health monitoring.

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Aigbodion, V. S., e P. A. Ozor. "New Insights into the Polymer Coating of Mild Steel Using Activated Orange Juice Functionalized Rice Husk Nanoparticles". In Lecture Notes in Mechanical Engineering, 1037–43. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-28839-5_115.

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AbstractNovel insights in the development of polymer coating of mild steel using functionalization of rice husk ash nanoparticles by activated orange juice were investigated. For the potentiostat/galvanostat corrosion performance of the coated materials, 5 wt% potassium sulfate (K2SO4(aq), 5 wt% sodium chloride (NaCl(aq), and 1 M sulfuric acid (H2SO4(aq) were used. 78.81, 71.86, and 55.11% corrosion resistance of the samples of K2SO4, H2SO4, and NaCl. It was concluded that orange juice was able to enhance the dispersion of RHnp in the epoxy coating. The presence of citrate ions in the orange juice acts as a stabilizer and reducing agent, which was attributed to the fine grain size and good corrosion resistance of the composite coating. The work has established that rice husk ash nanoparticles by activated orange juice can be used in the development of composites coating mild steel.

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Tan, X., B. Liu, W. Hong, G. F. Chang e X. F. Zou. "Adsorption properties of modified powdered activated carbon on salicylic acid wastewater". In Advances in Materials Science, Energy Technology and Environmental Engineering, 379–82. P.O. Box 11320, 2301 EH Leiden, The Netherlands, e-mail: Pub.NL@taylorandfrancis.com , www.crcpress.com – www.taylorandfrancis.com: CRC Press/Balkema, 2016. http://dx.doi.org/10.1201/9781315227047-75.

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Lee, Joon Jae, Jeong Kwon Suh, Ji Sook Hong, Jung Min Lee e Jin Won Park. "Physicochemical Characteristics of ZnS Immobilized on Spherical Activated Carbon for Removing HA(Humic Acid)". In Eco-Materials Processing and Design IX, 37–40. Stafa: Trans Tech Publications Ltd., 2008. http://dx.doi.org/10.4028/0-87849-472-3.37.

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Rathod, Yashpal, Anup Parmar e Wasudeo Gurnule. "NOVEL RELATIVE STUDIES: SYNTHESIS, CHARACTERIZATION OF COPOLYMER COMPOSITES AND THEIR ANTIMICROBIAL STUDY". In Futuristic Trends in Chemical Material Sciences & Nano Technology Volume 3 Book 18, 112–22. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/v3bdcs18ch10.

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The antimicrobial study of copolymer/activated charcoal composites underwent a unique comparative analysis. 8-hydroxyquinoline5-sulphonic acid, guanidine and formaldehyde were utilized to create the copolymer resin, and activated charcoal was used to create the new composite. The properties and structure of the copolymer and the copolymer/activated charcoal composite were assessed using a variety of characterisation methods, such as FTIR, NMR (1H), elemental analysis, and SEM. The differences in the antibacterial activity of copolymer/activated charcoal composites could be attributed to the material's nature, metal ions, high porosity, large surface area, and particle size. Additionally, the copolymer's and its composite's antibacterial outcomes were contrasted.

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Soonmin, Ho. "ACTIVATED CARBON: RECENT PROGRESS AND APPLICATIONS". In Futuristic Trends in Chemical Material Sciences & Nano Technology Volume 3 Book 10, 91–108. Iterative International Publisher, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/v3bbcs10p3ch2.

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Activated carbon has a larger surface area and well-developed porosity. It could be served as an absorbent to absorb unwanted materials. Synthesis of activated carbon is carried out via carbonization, physical activation, or chemical activation process. Precursors could be from agri-food industry wastes, municipal wastes, wood, and agricultural wastes. During the production of activated carbon, activating agent will be employed to develop porosity. Research findings indicated that an alkaline hydroxide was used for highly ordered (anthracites)whilezinc chloride and phosphoric acid were employed for low-ordered precursors (lignocellulosic), respectively. Freundlich model and Langmuir isotherm were applied to multi-layer and mono-layer adsorption, respectively. In conclusion, the adsorption capacity (dyes, heavy metals, carbon dioxide and organic pollutants) was strongly depended onto experimental conditions.

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Kumarasamy, Gayathri, Sathishkumar Samiyappan e Nirmaladevi Samiappan. "FUNCTIONALIZED POLYACRYLAMIDE/GRAPHITE COMPOSITES AS AN ADSORBENTS FOR THE DECOLOURISATION OF SYNTHETIC DYES AND DYEING INDUSTRY EFFLUENT FROM FABRIC PROCESSING UNITS". In Futuristic Trends in Chemical Material Sciences & Nano Technology Volume 3 Book 16, 18–26. Iterative International Publishers, Selfypage Developers Pvt Ltd, 2024. http://dx.doi.org/10.58532/v3bjcs16p1ch2.

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In this study we have compared the decolourisation of dyeing industry effluents collected in fabric processing units and synthetic dyes like direct blue 2b, acid violet 17, reactive red M5B and methylene blue 9 from aqueous solution using functionalized polyacrylamide/graphite composites such as glucose grafted polyacrylamide/graphite, glucosamine grafted polyacrylamide/graphite and commercial activated carbon as adsorbents. The adsorption studies are performed by varying the experimental parameters like temperature, time, adsorbate concentration and adsorbent dose. The various physicochemical parameters of dyeing industry effluents such as colour, pH, conductivity, total dissolved solids, hardness, alkalinity, chloride, sulphate, dissolved oxygen, chemical oxygen demand and bio-chemical oxygen demand of the effluents are analyzed before and after adsorption by the standard methods. It is observed that the synthesized adsorbents show more efficiency towards the removal of synthetic dyes from aqueous solution than the decolourisation of dyeing industry effluent. The amount of adsorbents required and cost analysis to treat 10 M3 of effluent is also studied and compared with commercial activated carbon.

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Jeffery-Smith, Anna, e C. Y. William Tong. "The Biology of Viruses". In Tutorial Topics in Infection for the Combined Infection Training Programme. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198801740.003.0008.

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In order to be classified as a virus, certain criteria have to be fulfilled. Viruses must ● Be only capable of growth and multiplication within living cells, i.e. obligate intracellular parasite. Host cells could include humans, animals, insects, plants, protozoa, or even bacteria. ● Have a nucleic acid genome (either RNA or DNA, but not both) surrounded by a protein coat (capsid). ● Have no semipermeable membrane, though some have an envelope formed of phospholipids and proteins. ● Be inert outside of the host cell. Enveloped viruses are susceptible to inactivation by organic solvents such as alcohol. ● Perform replication by independent synthesis of components followed by assembly (c.f. binary fission in bacteria). Viruses are considered as a bundle of genetic programmes encoded in nucleic acids and packaged with a capsid +/ - envelope protein, which can be activated on entry into a host cell (compare this with computer viruses packaged in an enticing way in order to infect and take over control of your PC). Although they share some similarities in their properties, mycoplasma and chlamydia are true bacteria. The virion (assembled infectious particle) consists of viral nucleic acid and capsid. The nucleic acid of a virus can either be ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), and the amount of genetic material varies widely, with some viruses able to encode a few proteins and others having genetic material that encodes hundreds of proteins. In association with the nucleic acid there may be non- structural viral proteins, such as a viral polymerase. The nucleic acid and non- structural proteins are protected by a surrounding layer of capsid proteins. The capsid includes proteins which can attach to host cell receptors. The proteins and the cell receptors to which they bind determine a virus’ tropism, i.e., the ability to bind to and enter different cell types. The term nucleocapsid refers to the nucleic acid core surrounded by capsid protein. Some viruses also have an envelope made up of phospholipids and proteins surrounding the nucleocapsid. This envelope can be formed by the host cell membrane during the process of a virus budding from a cell during replication.

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İsmail Tosun, Yıldırım. "Adsorption of Heavy Metals by Microwave Activated Shale/Asphaltite Char/Zeolite Granule Composts from Hazardous Sludges and Industrial Waste Slurries". In Clay Science and Technology [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94404.

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There is a great concern about surface water pollution with high level mercury, lead (Pb) over 10 mg/l, 30 mg/l to the fishing lakes and streams in Şırnak Province even contaminating fresh water fishing and poisonening of human by merury and lead in thr region. The chromium over 50 mg/l from industrial seepages was disposed to lakes and streams in our country. There is a great green concern prompting land in order to control acidic mine waters so that the research study controlled and avoided hazardous metal limits of residual stream contaminants of heavy metals by sorption local clay and zeolite compost. The contamination rate changes to those based on seepage concentrations and wetness. The stream amendments, such as shale char carbonized from Şırnak asphaltite containing 52–60% shale activated by acid washing under microwave radiation as geo material composted for waste water treatment should control contaminated effluents concentration. The field studies to evaluate the stability of heavy metal concentrations and salts were scarce. The initial objective of this study was to determine the effects of seepage flow to surface and groundwater from the industrial discharge. In this study, important investigations have been made on composite granules production with Şırnak shale char and zeolite feed in order to activated in microwave oven 2 M HCl dissolution. The compost sorbent for high level heavy metal sorption in laboratory water packed bed column adsorption compost system. However, the results of filled packed bed zeolite yield high metal transfer to compost. Due to the complex chemistry of shale pores, and high porosity, heat conduction improved in the microwave sorption depended on granule size decreased. The other heavy metal sorption distribution was changed in the activation dependent on the microwave heating power.

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Upadhyay, Virendra, Rajat Sengar e Sudhir Kumar Verma. "Assessment of C.I. ACID RED 2 Adsorption From Aqueous Solution by Modified, Activated, and Raw Water Hyacinth as a Low-Cost Green Adsorbent". In Advances in Chemical and Materials Engineering, 163–86. IGI Global, 2024. http://dx.doi.org/10.4018/979-8-3693-5320-2.ch008.

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The kinetic and isotherms of the adsorption of the C. I. Acid Red 2 onto raw, activated, and modified water hyacinth were studied. Modern techniques used to classify the new agricultural-based biosorbents are FTIR, SEM, TGA, DSC, and XRD. Raw water hyacinth (RWH), activated water hyacinth (AWH), and modified water hyacinth (MWH) were used as green biosorbents in this study. On the decolorization of dye (C. I. Acid Red 2), the consequences of operating parameters such as contact time, the quantity of adsorbent dosage (0.1 to 0.6 g), initial dye concentration, temperature, and pH (2 to 10) have been investigated. Langmuir, Temkin, and Freundlich's modern isotherms were used to interpret equilibrium statistics. At pH 7 the MWH displays the most dye removal (93%), the AWH shows 82% decolorization at pH 8 and RWH also shows maximum adsorption at pH 8 of the dye. In the case of MWH, the maximum adsorption capacity was found to be 93% at 0.4g adsorbent dosage. The MWH was discovered to be a very effective adsorbent for C.I. Acid Red 2 adsorption in all biosorbents. The removal of C.I. Acid Red 2 dye from aqueous solutions is necessary because it has both human and environmental consequences. Raw water hyacinth, activated water hyacinth, and modified water hyacinth appear as a very prospective green adsorbent for the separation of C. I. Acid Red 2 from aqueous solution.

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Trabalhos de conferências sobre o assunto "Acid-activated material"

Simatupang, Partogi H. "Characteristics of alkali activated material (geopolymer) in sulfuric acid solution". In GREEN CONSTRUCTION AND ENGINEERING EDUCATION FOR SUSTAINABLE FUTURE: Proceedings of the Green Construction and Engineering Education (GCEE) Conference 2017. Author(s), 2017. http://dx.doi.org/10.1063/1.5003511.

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Kumar, Awinash, Pradip Lingfa, Nabam Hina Papu e Moiching Sajit Ahamed. "Characterization of acid-activated sodium bentonite clay: A potential catalyst for recycling plastic wastes". In PROCEEDINGS OF ADVANCED MATERIAL, ENGINEERING & TECHNOLOGY. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0024321.

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Qin, Hangdao, Hui Li, Yong Wang e Jing Chen. "Removal of Benzoic Acid by Catalytic Ozonation with CeO2 Loaded on N, S Co-Doped Activated Carbon Catalyst". In 2nd International Conference on Material Science, Energy and Environmental Engineering (MSEEE 2018). Paris, France: Atlantis Press, 2018. http://dx.doi.org/10.2991/mseee-18.2018.51.

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V., Aswani, Shobha Elizabeth Thomas e Ramaswamy K. P. "Effect of Admixtures in Blast Furnace Slag-fly Ash Based Alkali-activated Paste". In 6th International Conference on Modeling and Simulation in Civil Engineering. AIJR Publisher, 2023. http://dx.doi.org/10.21467/proceedings.156.29.

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Portland cement can be replaced with alkali-activated binders (AABs), a sustainable material. They make use of industrial byproducts rich in aluminosilicates to produce hardened binders under alkaline conditions. The effective utilization of alkali-activated binders in each particular place is greatly influenced by the ease in accessibility of suitable precursors and activators. Slag-based AAB can make a strong and durable mix under ambient curing. But its poor workability and fast setting characteristics limit its scope of wide applications. The purpose of this investigation is to determine the effect of admixtures on the setting time of Alkali-activated Paste with blends of slag and fly ash (BFS-FA AAP). A combination of red gypsum and phosphoric acid is the admixture considered for the study. Setting time of BFS-FA AAP activated with sodium hydroxide and sodium silicate is studied considering different control factors, including Na2O/b ratio, BFS/binder and activator modulus (SiO2/ Na2O). The phosphoric acid, when added at 0.45 M along with red gypsum at 2.5% of binder content retarded the setting time of AAP effectively.

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Hornstra, E. G., A. H. Hennissen, R. Kalafusz e D. T. S. Tan. "THE ANTITHROMBOTIC EFFECT OF PALM OIL IS CORRELATED WITH ITS CONTENTS OF VITAMIN E". In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643804.

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Dietary saturated fatty acids are known to increase platelet aggregation and arterial thrombogenesis.We recently demonstrated, however, that palm oil, rich in saturated palmitic acid, has a distinct antithrombotic affect, which is associated with a decrease of the thromboxane-prostacyclin ratio in activated whole blood. To identify the antithrombotic component(s) of palm oil, seven palm oil fractions were prepared with comparable fatty acid compositions of the triglycerides but containing Various amounts of non-triglyceride material with different compositions.These fractions were fed to rats in amounts of 50 energy% for a period of 8 weeks, after which arterial thrombosis tendency was measured upon insertion of an aortic prosthesis, the aorta-loop. During loop insertion, 1 ml blood was collected in citrate for measuring platelet aggregation and ATP release in response to collagen, using the Chronolog whole blood lumi-aggregometer. Arterial thrombosis tendency was found to be negatively related to the total amount of non-triglyceride material in the various fractions (r = 0.78; p <0.05).No significant relationship was observed between arterial thrombus formation and the various sterols present in the non-triglyceride material.A significant negative correlation was found, however, with a-tocopherol (r = 0.86; p <.02). Collagen-induced platelet aggregation and ATP release in whole blood were not correlated to total amounts or α-tocopherol content of the non-triglyceride material.However, significant positive relationships were found between these platelet functions and the amountsof the various sterols (Campesterol: r = 0.70; P < 0.10 β-sitostero1 : r = 0.69; P <0.10. Cholesterol : r = 0.81; P < 0.05).These findings demonstrate that effects of edible oils on platelet function and arterial thrombogenesisare not only mediated by the fatty acid compostion of the triglycerides, but can also be determined by 'minor components', present in the non-triglyceride part of the oils.

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Al-Yami, Abdullah, Vikrant Wagle, Khawlah Al-Anqari, Abdulwahab Aljohar e Salah Elkatatny. "Curing Losses: Lab Developments and Best Practices". In International Petroleum Technology Conference. IPTC, 2022. http://dx.doi.org/10.2523/iptc-22007-ms.

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Abstract Moderate to severe loss circulation problem encountered while drilling is a major economic burden that increases the total well construction cost dramatically in some cases. This study will focus on best practices to mitigate curing losses in terms of prevention of potential loss by pre-treatment, locating and identifying the losses, identify the mechanism of losses and severity, curing losses strategies and their best drilling practices. In addition, the study will detail typical curing losses materials and their limitations. Finally, selected examples of recent developments in curing losses materials are detailed. The examples are activated nanoparticles dispersed fluid, Epoxy polymer resins, and sodium acid soluble cement solutions. Pre-treatment of loss circulation zone with proper size of bridging materials can reduce and eliminate mud losses into porous formations. The choice of bridging agents will depend on the formation characteristics. The moment of the occurrence (while drilling, circulating or tripping), the severity of the loss (seeping, partial or complete) and the exposed formations are the key factors to identify the best remedy for loss circulation. Losses to reservoir zones are handled differently than non-reservoir zones, wherein only acid soluble or non-damaging material is used in the pay-zone. Seepage losses occur in any formation type when the particle size distribution of the bridging agents is not optimum enough to create an effective seal. This paper describes three different types of novel loss circulation materials to control moderate to severe losses. The paper describes the development of a novel nanoparticle-based chemical treatment composition for its potential use as a loss circulation material. The gelation times were evaluated at different temperatures up to 300°F. The effects of pH and different concentration of activators on gelation times of the new treatment fluid has also been studied. Second example of LCM described in this paper is a novel resin composition comprising an epoxy resin and chemical activator to treat moderate to severe losses. The effect of the chemical activator concentration on the setting time of the resin composition was investigated to accomplish a controlled and delayed polymerization. The third example of LCM described in this paper involves a formulation consisting of an acid soluble cement and a sodium silicate gel that has a high potential to control moderate to severe loss circulation problem. The objective of this acid soluble loss circulation system technology was to design a solution to cure lost circulation in reservoir zones. This is the first study to discuss and detail such topics related to curing losses.

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Kamble, Mithil, Nikhil Koratkar e Catalin Picu. "Vitrimer Composites for Rotorcraft Components". In Vertical Flight Society 77th Annual Forum & Technology Display. The Vertical Flight Society, 2021. http://dx.doi.org/10.4050/f-0077-2021-16896.

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Carbon fiber reinforced composites (CFRP) are frequently used in rotorcraft components due to their high strength to weight ratio. Carbon fibers are the principal load carriers whereas polymer matrix provides structural integrity to the CFRP components. Fatigue failure originating in the matrix pose a design constraint on CFRP components. The fatigue failure originates in form of small scale sub-critical cracks which eventually grow into macroscopic cracks/shear localization resulting in eventual failure. Research efforts have been directed at improving fracture and fatigue performance of polymeric matrix by arresting incipient cracks. Thermoset polymers are widely used as matrix material as they posses superior strength due to high crosslinking density. However, since no self-healing mechanism operates in thermosets, damage is irreversibly accumulated over the life cycle of components. A new class of materials called vitrimers provide a novel approach to develop fatigue resistant CFRP. Vitrimers are associative covalent adaptive networks (CAN) which have reversible crosslinking reactions which can be activated by external energy stimulus like heat. As the crosslinked network is reversible, the incipient damage can be 'healed' by application of heat. In this work we explore the self-healing properties of vitrimer fabricated by the reaction of adipic acid and epoxy resin. The vitrimer is initially tested in static tests to probe mechanical properties, followed by fatigue experiments. The vitrimer is then used to make a vitrimeric CFRP (vCFRP) composite and is tested for its static and fatigue performance.

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Littlefield, Andrew G., Stephen F. Bartolucci e Joshua A. Mauer. "A Study on the Use of Graphene-PEEK Composites As High Temperature Adhesives: Mechanical Properties and Microwave Activation". In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70412.

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Polyetheretherketone is a widely used engineering polymer that is especially suitable for high-temperature applications. Graphene is a two-dimensional form of carbon nanomaterial that has been studied extensively for its mechanical, electrical and thermal properties and its use as a filler in polymer matrices. Compounding graphene into polymers has the potential to improve various properties, even at very low concentrations. In this work, we have examined the incorporation of graphene nanoplatelets (GNP) into PEEK. We have fabricated composites using melt-mixing techniques, as well as by graphene functionalization and in-situ polymerization of the PEEK. In this way, we can compare the performance of the composites by two different processing methods. The GNP-PEEK composites were characterized by DSC, TGA, and SEM. Lap-shear joints using the GNP-PEEK as the adhesive were made and mechanically tested. Results show that the weight fraction of GNP has a major effect on the strength of the joint. In this work, we aim to produce a material that functions as a reusable high-temperature, thermoplastic adhesive, which can be activated by conventional heating methods, or by microwave heating. The GNPs act as microwave absorbers and heat the surrounding PEEK matrix to the point of melting, in contrast to the neat PEEK, which does not melt upon exposure to the microwaves under the same parameters. Additionally, we explore 3D printing methods to fabricate a lap shear joint, where the adherends are pure polymer and the adhesive region is a polylactic acid/carbon nanofiber (PLA/CNF) composite that can be activated by microwaves. We show that solid adherends can be bonded together when a solid PLA/CNF piece is placed between the adherends and melted by microwave exposure. The microwave absorption properties and adhesive properties will be discussed.

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Ceban, Irina, Raisa Nastas e Tudor Lupascu. "Adsorption of caffeic acid on activated carbons". In Scientific seminar "Advanced materials to reduce the impact of toxic chemicals on the environment and health". Institute of Chemistry, Republic of Moldova, 2023. http://dx.doi.org/10.19261/admateh.2023.ab07.

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Denduluri, Veerabhadra S., George Ulerio II, Moneeb Genedy, Maria Juenger e Eric van Oort. "Experimental Investigation of Geopolymers for Application in High-Temperature and Geothermal Well Cementing". In SPE/IADC International Drilling Conference and Exhibition. SPE, 2023. http://dx.doi.org/10.2118/212491-ms.

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Abstract With recurrent calls for a reduction in carbon emissions, geothermal energy has received increasing attention in recent years as a prominent source of clean energy. With current drilling technology, geothermal wells are being constructed in extremely challenging temperature environments, which could reach up to 600°F/315°C in-situ temperature and beyond. However, geothermal well-cementing technology has not changed much over the past few decades, with Ordinary Portland Cement (OPC) still being the primary choice of cementing material. OPC has several drawbacks such as brittle behavior, shrinkage upon setting, poor bond strength to formation and casing, susceptibility to acid gas attack, temperature-induced strength retrogression, low tolerance towards drilling fluid contamination, etc. These factors could lead to a poor cementing job, thus compromising well integrity and not ensuring proper zonal isolation for the life of the geothermal well. Thus, there is a need to develop an alternative material that is compatible with the geothermal environment and able to provide long-term zonal isolation. With a low carbon footprint, self-healing ability, and low shrinkage sensitivity, geopolymers or alkali-activated materials could be a suitable option to augment or even replace OPC. Some of the previous studies on geopolymers have shown that they could be a potential candidate for oil and gas well cementing and civil engineering applications, with some being stable at very high temperatures (up to 1470°F/800°C). Geopolymers are formed by mixing an aluminosilicate source such as fly ash with an alkali-activating solution, such as sodium or potassium hydroxide or silicate. The aim of the study reported here is to demonstrate the applicability of geopolymers for geothermal well cementing. An experimental investigation was carried out to understand the behavior of geopolymer formulations made from fly ash, metakaolin, and blast furnace slag in a high-temperature environment. The material properties such as porosity, viscosity, thickening/pump time, compressive strength, tensile strength, and bond strength were tested in the laboratory. It was found that geopolymer formulations can be formulated to have the desired rheological properties with adequate pump time and resistance to drilling fluid contamination. In addition, the formulations can exceed the required compressive and tensile strength for geothermal cementing operations, while obtaining excellent bond strength values. These findings indicate that geopolymers are cementing materials that are well-suited to provide long-term zonal isolation in high-temperature geothermal wells.

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Relatórios de organizações sobre o assunto "Acid-activated material"

Kennedy, Alan, Mark Ballentine, Andrew McQueen, Christopher Griggs, Arit Das e Michael Bortner. Environmental applications of 3D printing polymer composites for dredging operations. Engineer Research and Development Center (U.S.), janeiro de 2021. http://dx.doi.org/10.21079/11681/39341.

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This Dredging Operations Environmental Research (DOER) technical note disseminates novel methods to monitor and reduce contaminant mobility and bioavailability in water, sediments, and soils. These method advancements are enabled by additive manufacturing (i.e., three-dimensional [3D] printing) to deploy and retrieve materials that adsorb contaminants that are traditionally applied as unbound powders. Examples of sorbents added as amendments for remediation of contaminated sediments include activated carbon, biochar, biopolymers, zeolite, and sand caps. Figure 1 provides examples of sorbent and photocatalytic particles successfully compounded and 3D printed using polylactic acid as a binder. Additional adsorptive materials may be applicable and photocatalytic materials (Friedmann et al. 2019) may be applied to degrade contaminants of concern into less hazardous forms. This technical note further describes opportunities for U.S. Army Corps of Engineers (USACE) project managers and the water and sediment resource management community to apply 3D printing of polymers containing adsorptive filler materials as a prototyping tool and as an on-site, on-demand manufacturing capability to remediate and monitor contaminants in the environment. This research was funded by DOER project 19-13, titled “3D Printed Design for Remediation and Monitoring of Dredged Material.”

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Kanner, Joseph, Edwin Frankel, Stella Harel e Bruce German. Grapes, Wines and By-products as Potential Sources of Antioxidants. United States Department of Agriculture, janeiro de 1995. http://dx.doi.org/10.32747/1995.7568767.bard.

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Several grape varieties and red wines were found to contain large concentration of phenolic compounds which work as antioxidant in-vitro and in-vivo. Wastes from wine production contain antioxidants in large amounts, between 2-6% on dry material basis. Red wines but also white wines were found to prevent lipid peroxidation of turkey muscle tissues stored at 5oC. The antioxidant reaction of flavonoids found in red wines against lipid peroxidation were found to depend on the structure of the molecule. Red wine flavonoids containing an orthodihydroxy structure around the B ring were found highly active against LDL and membrane lipid peroxidation. The antioxidant activity of red wine polyphenols were also found to be dependent on the catalyzer used. In the presence of H2O2-activated myoglobin, the inhibition efficiency was malvidin 3-glucoside>catechin>malvidin>resveratol. However, in the presence of an iron redox cycle catalyzer, the order of effectiveness was resveratol>malvidin 3-glucoside = malvidin>catechin. Differences in protein binding were found to affect antioxidant activity in inhibiting LDL oxidation. A model protein such as BSA, was investigated on the antioxidant activity of phenolic compounds, grape extracts, and red wines in a lecithin-liposome model system. Ferulic acid followed by malvidin and rutin were the most efficient in inhibiting both lipid and protein oxidation. Catechin, a flavonal found in red-wines in relatively high concentration was found to inhibit myoglobin catalyzed linoleate membrane lipid peroxidation at a relatively very low concentration. This effect was studied by the determination of the by-products generated from linoleate during oxidation. The study showed that hydroperoxides are catalytically broken down, not to an alcohol but most probably to a non-radical adduct. The ability of wine-phenolics to reduce iron and from complexes with metals were also demonstrated. Low concentration of wine phenolics were found to inhibit lipoxygenase type II activity. An attempt to understand the bioavailability in humans of antocyanins from red wine showed that two antocyanins from red wine were found unchanged in human urine. Other antocyanins seems to undergo molecular modification. In hypercholesterolemic hamsters, aortic lipid deposition was significantly less in animals fed diets supplemented with either catechin or vitamin E. The rate of LDL accumulation in the carotid arteries was also significantly lower in the catechin and vitamin E animal groups. These results suggested a novel mechanism by which wine phenolics are associated with decreased risk of coronary heart diseases. This study proves in part our hypothesis that the "French Paradox" could be explained by the action of the antioxidant effects of phenolic compounds found at high concentration in red wines. The results of this study argue that it is in the interest of public health to increase the consumption of dietary plant falvonoids. Our results and these from others, show that the consumption of red wine or plant derived polyphenolics can change the antioxidant tone of animal and human plasma and its isolated components towards oxidative reactions. However, we need more research to better understand bioavailability and the mechanism of how polyphenolics affect health and disease.

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