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1
Savelyev, Yuriy. "Polyurethane Functional Coatings for Protection of Different Surfaces from Aggressive Environmental Factors". Nauka ta innovacii 10, n. 3 (3 giugno 2014): 28–34. http://dx.doi.org/10.15407/scin10.03.028.
Testo completoAbstract (sommario):
New polyurethane compositions (PC) as multifunctional protective materials that can serve as coatings or binders or impregnating materials have been created. PC have high adhesion values and the PC-based materials are waterproof and resistant to aggressive biotic (abiotic) and technogenic factors (biocorrosion, UV radiation, chemical agents). Putting active compounds into the polymer macrochain prolongs the protection functions of the materials. This is their advantage to existing materials.
2
Shrestha, Dibyashree. "Removal of Eosin Y Dye using Activated Carbons from Modified Wood Dust Powder of Dalbergia sisoo". Patan Pragya 8, n. 01 (31 dicembre 2021): 57–72. http://dx.doi.org/10.3126/pragya.v8i01.42356.
Testo completoAbstract (sommario):
An agro-waste/wood-dust of Dalbergia sisoo (Sisau)derived activated carbons have been applied as a potential adsorbent to remove anionic dye “Eosin Y” from aqueous solution. The activated carbons were synthesized by carbonization technique. The chemical activation was done by impregnating with three different impregnating agents, i.e. acid, base and salt, namely phosphoric acid (H3PO4) , potassium hydroxide (KOH) and sodium carbonate (Na2CO3). The prepared activated carbons were characterized by various instrumental techniques like TGA/DSC, XRD, Raman, FTIR, SEM and BET. The BET analysis gave the evidence of micropores and mesopores in the samples. The H3PO4 activated carbon sample revealed higher surface area than KOH and Na2CO3 activated samples. The amorphous nature of the sample was observed on the basis of XRD and Raman spectroscopy technique. The adsorption of dye was performed by varying the dye concentration, pH and sample dose. The maximum percent of dye removal by H3PO4 activated carbon (Dal-A) for Eosin Y was found to be 99.9 % at an aqueous solution of 20ppm, pH 3.5, adsorbent dose of 30 mg and 5 min of time as compared to KOH and Na2CO3 activated carbons; Dal-B and Dal-C respectively. This study proved to be highly successful in addressing the local problem of wastewater pollution of garment and textile industrial effluents using locally available wood dust of Dalbergia sisoo. Acidic pH environment was found to be more conducive in the removal of Eosin Y dye.
3
Al-Asheh, Sameer, Fawzi Banat e Asmahan Masad. "Use of Activated Oil Shale for the Removal of 2,4-Dichlorophenol from Aqueous Solutions". Water Quality Research Journal 40, n. 2 (1 maggio 2005): 211–21. http://dx.doi.org/10.2166/wqrj.2005.024.
Testo completoAbstract (sommario):
Abstract Sorption of the phenolic compound 2,4-dichlorophenol (2,4-DCP) by pyrolyzed and different forms of treated residue of Jordanian oil shale was examined. Pyrolyzed oil shale was prepared using a fluidized bed reactor at 520ºC in the presence of nitrogen. Physical activation was carried out by treating the resultant pyrolyzed oil shale with CO2 at 830ºC, while chemical activation of oil shale was carried out using KOH and ZnCl2 as impregnating agents. Uptake of 2,4-DCP onto the different types of sorbents increased in the order ZnCl2-OS > Pyr-OS > CO2-OS, with minimal uptake when KOH-OS was used. The process was found to be exothermic in nature. An increase in the initial pH of the solution negatively influenced the sorption of 2,4-DCP. The isotherm experimental data fitted reasonably to the Langmuir, Freundlich and Redlich-Paterson models. According to kinetics studies, the rate of 2,4-DCP sorption onto ZnCl2-OS was faster than that by Pyr-OS. Three kinetics models, namely the Morris-Weber model, Lagergren model, and pseudo-second-order model (PSOM), were applied to represent the experimental results for both pyrolyzed and ZnCl2-oil shale sorbents.
4
Stawowiak, Michał, Marcel Żołnierz e Zenon Rożenek. "Research on the coefficient of friction of becorit K22 and K25SB linings". New Trends in Production Engineering 2, n. 1 (1 ottobre 2019): 367–75. http://dx.doi.org/10.2478/ntpe-2019-0039.
Testo completoAbstract (sommario):
Abstract The article presents the method and results of experimental tests of the coefficient of friction between a steel rope and friction lining. The BECORIT K22 and BECORIT K25SB floor coverings were tested. The tests were carried out in accordance with the recommendations of the new German standard: DIN 21258 – Lubricants and impregnating agents for drive discs and transport ropes in mining – safety and testing requirements. The authors in this article emphasize that the Becorit K22 and K25SB linings are used for the wheels of propeller drums of mining machines. Characterized by high coefficients of friction (μ ≥ 0.25), also in cases of extreme weather conditions on the surface. The chemical properties of BECORIT linings ensure their resistance to swelling in the event of different oils and lubricants as well as mine waters. The material of which the claddings are made ensures very good machinability during rolling of rope grooves with the use of turning or milling tools. BECORIT K22 plastic cladding is particularly suitable for use in hoisting machines, where the rope base forms a large overlap angle on the wheel grooves (max 1°31'), which causes its lateral wear faster. BECORIT K22 material in this case provides a higher service life compared to other materials. Due to the way they are mounted on the wheel, they are made as 1-piece (monolith) or bipartite. In this article, moreover, the structure and principle of operation of the measuring station on which the tests were carried out are presented in great detail.
5
de Bilbao, Emmanuel, Mathieu Dombrowski, Nicolas Traon, Thorsten Tonnesen, Jacques Poirier e Eric Blond. "Study of Reactive Impregnation and Phase Transformations during the Corrosion of High Alumina Refractories by Al2O3-CaO Slag". Advances in Science and Technology 92 (ottobre 2014): 264–71. http://dx.doi.org/10.4028/www.scientific.net/ast.92.264.
Testo completoAbstract (sommario):
Corrosion of refractories results from reactive transport namely, transport of agents and chemical reactions of these agents with impregnated medium. On one hand, the transport involves either diffusion or impregnation depending on the state of the corrosive agents and the microstructure of the host media. On the other hand, chemical reactions may be very numerous and complex. This study focused on the reactive impregnation of Al2O3-CaO slag into porous high alumina refractory.Transport properties of the porous media have been assessed by performing wicking test. Chemical reactions between the solid high alumina skeleton and Al2O3-CaO slag involve successive dissolution/precipitation mechanisms forming aluminates of lime. Contrary to the thermodynamic properties of the binary system, the kinetics of these solid/liquid reactions is not well known. Corrosion tests associated with quenching method, XRD and high temperature XRD were performed for a better understanding of the kinetics.
6
Zhang, Lingxia, Jianlin Shi, Jiangtian Li, Zile Hua e Meiling Ruan. "Carbon nanostructures formed on mesoporous silica by catalytic chemical vapor deposition of ethene". Journal of Materials Research 23, n. 2 (febbraio 2008): 435–43. http://dx.doi.org/10.1557/jmr.2008.0047.
Testo completoAbstract (sommario):
Three different strategies, wet impregnation, in situ reduction, and grafting with silane coupling agents, have been used to introduce CoNi nanoparticles with different existing forms into mesoporous silica. These composites were used as catalysts to grow nanostructured carbons by catalytic chemical vapor deposition using ethene. Carbon nanotubes (CNTs) with different inner diameters can grow out of mesoporous silica particles incorporated with CoNi nanoclusters. Many fewer CNTs could be found in the pore channels of the sample prepared by using silane coupling agents than in those of the sample synthesized via wet impregnation. No CNTs formed in the pore channels of the sample prepared by in situ reduction. After the removal of silica, different carbon nanostructures have been obtained in the pore channels. Ordered graphite carbon mesostructure was obtained from the sample prepared by in situ reduction. Highly dispersed metal catalysts inside mesopore channels are favorable for the formation of graphite carbons with ordered mesostructures.
7
Mohd Alias, Mohd Zazmiezi, Rozidaini Mohd Ghazi, Nik Raihan Nik Yusoff e Mohd Hafiz Jamaludin. "Effect of Activation Agents on COD Reduction Using Activated Carbon from Agricultural Residue". Materials Science Forum 1010 (settembre 2020): 453–58. http://dx.doi.org/10.4028/www.scientific.net/msf.1010.453.
Testo completoAbstract (sommario):
This study investigated the effect of activating agent on activated carbon preparation and potential chemical oxygen demand (COD) reduction using activated carbons (AC) prepared. Zinc chloride, phosphoric acid and potassium hydroxide were utilized in impregnation of bamboo and rice husk. Result of SEM-EDX, FTIR as well as COD reduction were compared and discussed. The SEM displayed highest porosity in AC using KOH activation. FTIR analysis displayed obvious difference for each activation. AC using KOH activation obtained highest COD reduction.
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Amran, Fadina, e Muhammad Abbas Ahmad Zaini. "Effects of chemical activating agents on physical properties of activated carbons – a commentary". Water Practice and Technology 15, n. 4 (17 ottobre 2020): 863–76. http://dx.doi.org/10.2166/wpt.2020.094.
Testo completoAbstract (sommario):
Abstract Well-developed surface areas and porous structures that render high adsorption capacity are necessary for pollutant removal from wastewater by activated carbons. Activated carbons from natural resources, and agricultural and industrial waste materials are produced using chemical agents, including KOH, H3PO4, K2CO3, ZnCl2 and NaOH. This study is intended to highlight the effects of those agents on the physical properties of the activated carbons. The operating conditions, i.e., temperature, time and ratio, show an interplay towards the physical properties at varying degree. The yield, pore size, mesoporosity and surface area of activated carbons derived using different chemical agents correlate well with the impregnation ratio. Generally, the pore size, mesoporosity and surface area increase, while the yield decreases with increasing ratio (over a given range). Higher ratio and temperature are recommended for KOH, K2CO3 and NaOH activation, to endow activated carbons with greater surface area.
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Suhdi e Sheng-Chang Wang. "Fine Activated Carbon from Rubber Fruit Shell Prepared by Using ZnCl2 and KOH Activation". Applied Sciences 11, n. 9 (28 aprile 2021): 3994. http://dx.doi.org/10.3390/app11093994.
Testo completoAbstract (sommario):
Fine activated carbon (FAC) is prepared from rubber fruit shells (RFS) using two chemical activating agents (ZnCl2 and KOH) and three impregnation ratios (1:3, 1:4, and 1:5). The Brunauer–Emmett–Teller (BET) results show that for a constant impregnation ratio, the ZnCl2 activating agent yields a higher specific surface area than the KOH agent. In particular, for the maximum impregnation ratio of 1:5, the FAC prepared using ZnCl2 has a BET surface area of 456 m2/g, a nitrogen absorption capacity of 150.38 cm3/g, and an average pore size of 3.44 nm. Moreover, the FAC structure consists of 70.1% mesopores and has a carbon content of 80.05 at.%. Overall, the results confirm that RFS, activated using an appropriate quantity of ZnCl2, provides a cheap, abundant, and highly promising precursor material for the preparation of activated carbon with high carbon content and good adsorption properties
10
Woo, Tae Gyun, Byeong Jun Cha, Young Dok Kim e Hyun Ook Seo. "Positive Effects of Impregnation of Fe-oxide in Mesoporous Al-Oxides on the Decontamination of Dimethyl Methylphosphonate". Catalysts 9, n. 11 (28 ottobre 2019): 898. http://dx.doi.org/10.3390/catal9110898.
Testo completoAbstract (sommario):
Dimethyl methylphosphonate (DMMP) is an important simulant of organophosphates pesticides and chemical warfare nerve agents. Here, we investigated the catalytic decontamination of DMMP on Fe-oxide impregnated mesoporous Al2O3. Fe-oxide/Al2O3 sample was prepared via the temperature regulated chemical vapor deposition of Fe-oxide on mesoporous Al2O3 and post-annealing at 750 °C. The Fe-oxide/Al2O3 and bare Al2O3 samples were exposed to DMMP-containing dry air at room temperature to study the effects of Fe-oxide impregnation on the reactive adsorption of DMMP. The facilitation of DMMP degradation into CO2 and methanol at room temperature in the presence of nano-dispersed Fe-oxide was evidenced by gas-chromatograph and Fourier transform-infrared (FT-IR) absorption spectroscopy. In addition, temperature programmed oxidation (TPO) experiments and gas chromatography (Agilent, 6890) equipped with mass spectrometer (Agilent, 5973N) (GC/MS) analyses revealed that the minimum temperature that was required for total oxidation of DMMP into CO2 can also be lowered by Fe-oxide impregnation in mesoporous Al2O3.
11
Zhang, Jingjing, Chungui Du, Rui Peng, Ailian Hu, Qi Li, Chunlin Liu, Yingying Shan, Shiqin Chen e Wenxiu Yin. "Antimildew Treatment and Control Effect of Citral on Bamboo". International Journal of Polymer Science 2021 (27 agosto 2021): 1–10. http://dx.doi.org/10.1155/2021/5949458.
Testo completoAbstract (sommario):
Presently, chemical agents remain the main antimildew agents for bamboo, which has a certain negative impact on the environment and human health. Therefore, it is urgent to develop new environment-friendly antimildew agents for bamboo. Here, citral, an environment-friendly natural antibacterial agent, was used as an antimildew agent for bamboo. The orthogonal test was used to explore the effects of citral concentration, impregnation pressure, and pressurization time on the drug loading capacity of treated bamboo strips. The effect of antimildew-treated bamboo strips on bamboo mold was also discussed. Furthermore, the Fourier transform infrared spectroscopy and ultraviolet spectrophotometer were used to investigate the distribution of citral in bamboo strips. Results showed that the optimum technological parameters of citral mildew-proof treatment of bamboo were as follows: citral concentration: 0.795 mg/ml, impregnation pressure: 0.3 MPa, and pressurization time: 90 min. Also, citral was easy to volatilize, which decreased the citral content of bamboo strips after vacuum drying and showed the trend of a lower surface layer and a higher inner layer. The concentration of citral therefore had a significant effect on the drug loading of the antimildew-treated bamboo strips. Thus, it was difficult to achieve effective prevention and control of bamboo mold when bamboo strips were impregnated with a lower concentration of citral solution. When the concentration of citral reached 200 mg/ml, the prevention and antimold efficiency of antimildew bamboo strips reached over 100%. This study will provide references for the development and application of environment-friendly natural antibacterial agents in the field of bamboo mildew prevention.
12
Aliasa, Norulaina, Muhammad Abbas Ahmad Zaini e Mohd Johari Kamaruddin. "Roles of Impregnation Ratio of K2CO3 and NaOH in Chemical Activation of Palm Kernel Shell". Journal of Applied Science & Process Engineering 4, n. 2 (3 ottobre 2017): 195–204. http://dx.doi.org/10.33736/jaspe.436.2017.
Testo completoAbstract (sommario):
The present work was aimed to evaluate the effectiveness of two activating agents, namely potassium carbonate (K2CO3) and sodium hydroxide (NaOH) in the chemical activation of palm kernel shell (PKS). The adsorbents were prepared by dried impregnation at different solid mass ratios of activating agent to precursor, followed by thermal treatment at 500°C for 2 h. The adsorbents were characterized for specific surface area, carbon content, ash content and surface functional groups. Results show that the specific surface of K2CO3-activated samples are in the range of 5.3 to 53 m2/g, while that of NaOH-activated samples are between 145 and 458 m2/g. The removal of methylene blue is in accordance with the development of surface area of adsorbents, with the maximum capacity between 7.8 and 69 mg/g, and fitted well with the Langmuir isotherm. The findings conclude that, under the thermal conditions studied, NaOH is better than K2CO3 in the chemical activation of PKS.
13
Okhovat, Ahmad, Ali Ahmadpour, Farzaneh Ahmadpour e Zahra Khaki Yadegar. "Pore Size Distribution Analysis of Coal-Based Activated Carbons: Investigating the Effects of Activating Agent and Chemical Ratio". ISRN Chemical Engineering 2012 (24 dicembre 2012): 1–10. http://dx.doi.org/10.5402/2012/352574.
Testo completoAbstract (sommario):
The present study attempts to investigate the effects of different chemical agents and chemical ratios on pore structure of coal-based activated carbons. The adsorption isotherm data of two series of activated carbons prepared from bituminous coal by chemical activation with potassium hydroxide and zinc chloride were used. Four well-known models of Dubinin-Stoeckli, Stoeckli, Horvath-Kawazoe, and improved Horvath-Kawazoe were applied for the characterization of these porous solids. Although the results showed some differences among the models that arise from their fundamental assumptions, in general they are found to be comparable. Results showed that samples activated by ZnCl2 provide higher-adsorption capacity than those from KOH. In each series, it was shown that the pore volume increases with increasing impregnation ratio, ranging from 50% to 200%. Activated carbons obtained at low chemical ratio in ZnCl2 series (up to 100%) showed microporous structure, while those with higher ratios became predominantly mesoporous. In the KOH series, increasing KOH created more micropores in the carbon structure in the whole range of studied chemical ratio.
14
Udkhiyati, Mustafidah, e Fitrilia Silvianti. "The Utilization of Chitosan as Natural Antibacterial for Vegetable Tanned Leather". Materials Science Forum 948 (marzo 2019): 212–16. http://dx.doi.org/10.4028/www.scientific.net/msf.948.212.
Testo completoAbstract (sommario):
Leathers, which are made from natural fibers, can serve as media for microorganisms to grow. The currently used antimicrobial agents or biocides in the leather industry are harmful to human health and the environment. Therefore, the use of antimicrobial agents should be restricted. This study aims at developing eco-friendly biocides that could substitute for toxic chemicals as it will be tested on vegetable-tanned leather. Due to their large surface area and ability to retain moisture, the vegetable tanned leather has a higher possibility of biodeterioration than other types of leathers tanned by mineral tanning agents. In this work, the natural biopolymer of chitosan was chosen for its ability to inhibit the bacterial growth. The results showed that chitosan coating by impregnation method in drum using chitosan/leather ratio of 1% in formic acid for 2 hours is successfully achieved the bacterial growth inhibition.
15
Khurshid, Hifsa, Muhammad Raza Ul Mustafa e Mohamed Hasnain Isa. "Modified Activated Carbon Synthesized from Oil Palm Leaves Waste as a Novel Green Adsorbent for Chemical Oxygen Demand in Produced Water". Sustainability 14, n. 4 (10 febbraio 2022): 1986. http://dx.doi.org/10.3390/su14041986.
Testo completoAbstract (sommario):
Palm tree waste is one of the most widespread forms of agricultural waste, particularly in areas where oil palms are cultivated, and its management is one of the industry’s key concerns. To deal with this palm waste, researchers are working hard to work out the ways to convert this plentiful waste into useful material for future beneficial applications. The objective of this study was to employ chemical activation techniques to prepare a new activated carbon (AC) using discarded oil palm leaves (OPL) in Malaysia. Three chemical agents (H3PO4, NaOH and ZnCl2), as well as three pyrolysis temperatures (400 °C, 600 °C and 800 °C) and various impregnation ratios (1:0.5–1:3) were used to optimize the preparation process. As a result, the oil palm leaves activated carbon (OPLAC), with prominent surface properties, was obtained by ZnCl2 activations with a 1:1 impregnation ratio and carbonized at a pyrolysis temperature of 800 °C. The OPLAC-ZC had a surface area of 331.153 m2/g, pore size of 2.494 nm and carbon content of 81.2%. Results showed that the OPLAC-ZC was able to quickly (90 min) remove the chemical oxygen demand (COD) from produced water (PW), through chemical adsorption and an intraparticle diffusion mechanism. The material followed pseudo-second order kinetic and Freundlich isotherm models. The maximum adsorption capacity of organic pollutants forming COD in PW was found to be 4.62 mg/g (59.6 ± 5%). When compared to previous studies, the OPLAC-ZC showed equivalent or better COD removal capability. It is the first detailed study reporting the preparation of AC from OPL and applying it for organic pollutants adsorption forming COD in PW.
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Sajjadi, Baharak, Tetiana Zubatiuk, Danuta Leszczynska, Jerzy Leszczynski e Wei Yin Chen. "Chemical activation of biochar for energy and environmental applications: a comprehensive review". Reviews in Chemical Engineering 35, n. 7 (25 ottobre 2019): 777–815. http://dx.doi.org/10.1515/revce-2018-0003.
Testo completoAbstract (sommario):
Abstract Biochar (BC) generated from thermal and hydrothermal cracking of biomass is a carbon-rich product with the microporous structure. The graphene-like structure of BC contains different chemical functional groups (e.g. phenolic, carboxylic, carbonylic, etc.), making it a very attractive tool for wastewater treatment, CO2 capture, toxic gas adsorption, soil amendment, supercapacitors, catalytic applications, etc. However, the carbonaceous and mineral structure of BC has a potential to accept more favorable functional groups and discard undesirable groups through different chemical processes. The current review aims at providing a comprehensive overview on different chemical modification mechanisms and exploring their effects on BC physicochemical properties, functionalities, and applications. To reach these objectives, the processes of oxidation (using either acidic or alkaline oxidizing agents), amination, sulfonation, metal oxide impregnation, and magnetization are investigated and compared. The nature of precursor materials, modification preparatory/conditions, and post-modification processes as the key factors which influence the final product properties are considered in detail; however, the focus is dedicated to the most common methods and those with technological importance.
17
Sirimuangjinda, Athiwat, Khanthima Hemra, Duangduen Atong e Chiravoot Pechyen. "Comparison on Pore Development of Activated Carbon Produced from Scrap Tire by Potassium Hydroxide and Sodium Hydroxide for Active Packaging Materials". Key Engineering Materials 545 (marzo 2013): 129–33. http://dx.doi.org/10.4028/www.scientific.net/kem.545.129.
Testo completoAbstract (sommario):
Activated carbons were prepared by chemical activation from scrap tire with two chemical reagents, NaOH and KOH. The activation consisted of different impregnation of a reagent followed by carbonization in nitrogen at 700°C. The resultant activated carbons were characterized in terms of BET surface area, methylene blue adsorption and iodine number. The influence of each parameter of the synthesis on the properties of the activated carbons was discussed, and the action of each hydroxide was methodically compared. It is the first time that preparation parameters and pore texture characteristics are simultaneously considered for two closely related activating agents of the same char precursor. Whatever the preparation conditions, it was shown that KOH led to the most microporous materials, having surface areas and adsorption properties (methylene blue adsorption and iodine number) higher than those obtained with NaOH, which was in agreement with some early works. However, the surface areas, methylene blue adsorption and iodine number obtained in the present study were much higher than in previous studies, up to 951 m2/g, 510 mg/g and 752 mg/g, respectively, using scrap tire waste char:KOH equal to 1:1. The thorough study of the way each preparation parameter influenced the properties of the final materials bought insight into the activation mechanisms. Each time it was possible; the results of scrap tire waste chemically activated with hydroxides were compared with those obtained with anthracites; explanations of similarities and differences were systematically looked for.
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Syahida Arsyad, Nor Amiera, Mohammad Khairul Azhar Abdul Razab, An’amt Mohamed Noor, Mohd Hazim Mohamad Amini, Nik Nurul Anis Nik Yusoff, Ahmad Zamani Abdul Halim, Nik Alnur Auli Nik Yusuf, Mohamad Najmi Masri, Muhammad Azwadi Sulaiman e Nor Hakimin Abdullah. "Effect of Chemical Treatment on Production of Activated Carbon from Cocos nucifera L. (Coconut) Shell by Microwave Irradiation Method". Journal of Tropical Resources and Sustainable Science (JTRSS) 4, n. 2 (13 agosto 2021): 112–16. http://dx.doi.org/10.47253/jtrss.v4i2.618.
Testo completoAbstract (sommario):
In recent years, activated carbon has attracted attention among researchers due to its special properties such as high porosity, highly adsorption and low cost. In this research, activated carbon has been successfully produced from the coconut shell by using the microwave irradiation method where zinc chloride (ZnCl2), phosphoric acid (H3PO4) and sodium hydroxide (NaOH) were implemented as the activating agents. The results showed that phosphoric acid has the most significant effect on the synthesized activated carbon properties. The optimum parameter for the power of microwave irradiation used was 380 W, impregnation ratio of activating agent to char was 3:1 for phosphoric acid, 2:1 for sodium hydroxide, and for 1:1 zinc chloride while concentration of each activating agents was 0.5 M with 10 minutes of activation time. All samples then were characterized by using, Moisture meter, FTIR-ATR, XRD and TGA in order to determine the functional groups, composition and element and weight loss of the activated carbon. This research could benefit the environment by recycling the agriculture waste into a new useful material as well as to keep the environment safe from pollution.
19
Islam, Md Nazrul, Keisuke Ando, Hidefumi Yamauchi, Daisuke Kamikawa, Toshiro Harada, H. P. S. Abdul Khalil e Nobuaki Hattori. "Impregnation of laser incised wood of Douglas fir and Japanese cedar by dipping (passive impregnation) in solutions of copper azole (CuAz-B) and a fire retardant (PPC)". Holzforschung 68, n. 3 (1 aprile 2014): 353–60. http://dx.doi.org/10.1515/hf-2013-0140.
Testo completoAbstract (sommario):
Abstract The performance of the passive impregnation method of CO2-laser incised lumber has been investigated concerning wood preservation against different wood-destroying agents. Copper azole type B (CuAz-B) preservative and polyphosphatic carbamate (PPC) fire retardant were impregnated into Douglas fir and Japanese cedar lumber under both green and kiln-dried conditions. Final drying of the lumber was performed by steam injection or kiln drying. The temperature and pressure change in the lumber, as well as the total chemical retention, penetration, decay resistance, fire retardancy and total treatment time were calculated according to different standards. The preservative retention was higher in the Japanese cedar for both green and kiln-dried conditions (5.32 and 5.58 kg m-3, respectively) compared to Douglas fir (5.01 and 4.81 kg m-3). Fire retardant retentions were more than 100 kg m-3 in all cases. The penetration was approximately 100% throughout the lumber. There were no significant differences in the decay resistance test between the different categories of lumber. Moreover, it was possible to treat the green lumber in less than 48 h starting from the green conditon to the final drying. Hence, the presented passive impregnation technique could be useful for industrial application.
20
Pan, Yiren, Meng Zhang, Jian Zhang, Xiaoyao Zhu, Huiguang Bian e Chuansheng Wang. "Effect of Silane Coupling Agent on Modification of Areca Fiber/Natural Latex". Materials 13, n. 21 (31 ottobre 2020): 4896. http://dx.doi.org/10.3390/ma13214896.
Testo completoAbstract (sommario):
In this paper, the areca fiber was extracted by physical and chemical treatment, and then the areca fiber/natural latex composite was prepared by natural latex impregnation technology. In order to combine areca fiber and natural rubber latex better, three silane coupling agents with different action mechanism were selected: Si−69, KH550, and KH570 which were used to treat the areca fiber/natural latex compound. The results show that the silane coupling agent can change the surface of the fiber from hydrophilic surface to organophilic surface, making the bonding of areca fiber to natural latex more closely. At the same time, the mechanical properties, physical and mechanical properties, swelling properties, and dynamic viscoelastic properties of the tightly bonded areca fiber/nature latex composites were improved. After observing the micro-structure through a scanning electron microscope, it was found that the three silane coupling agents could effectively bind areca fiber and natural latex to enhance the performance of the composite material, of which Si−69 performed best, and the tensile strength and tear strength of the composite increased by 21.19% and 12.90% respectively.
21
Sirimuangjinda, Athiwat, Duangduen Atong e Chiravoot Pechyen. "Comparison on Pore Development of Activated Carbon Produced from Scrap Tire by Hydrochloric Acid and Sulfuric Acid". Advanced Materials Research 626 (dicembre 2012): 706–10. http://dx.doi.org/10.4028/www.scientific.net/amr.626.706.
Testo completoAbstract (sommario):
Two activated carbons employing Scrap Tire as precursor were produced by using two different activating agents, HCl and H2SO4 (fixed impregnation ratio 1:1). Both of activated carbons were allowed by single-step to get difference carbonized at 500, 600 and 700°C in a muffle furnace for 1 h. Activated carbons differed with the physical structure, chemical and adsorption properties which were derived from Scanning Electron Microscope, and N2 adsorption/desorption isotherms. Batched sorption studies were performed to compare the iodine and methylene blue adsorption properties of two carbons. The carbon materials obtained from sulfuric acid activation of 500°C has BET surface area as high as 1066.70 m2/g, Methylene blue adsorption and Iodine number of 288.90 and 590.50 mg/g, respectively. The surface area and adsorption properties of carbon produced using sulfuric acid activation were higher than that produced using hydrochloric acid activation. The results suggest the feasibility of the process from the point of view of both porous texture and adsorption yield.
22
Ozbay, Nurgul, e Adife Seyda Yargic. "Comparison of Surface and Structural Properties of Carbonaceous Materials Prepared by Chemical Activation of Tomato Paste Waste: The Effects of Activator Type and Impregnation Ratio". Journal of Applied Chemistry 2016 (22 novembre 2016): 1–10. http://dx.doi.org/10.1155/2016/8236238.
Testo completoAbstract (sommario):
Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C). The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.%) on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW), and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG), Fourier transform-infrared (FT-IR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, point of zero charge measurements (pHPZC), particle size analyzer, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD) analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g) was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.
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Liu, Jinshu, Xiaoyan Ma, Wenzhao Shi, Jianwei Xing e Chaoqun Ma. "Grafting Modification of Natural Fibres with Cyclodextrin". Fibres and Textiles in Eastern Europe 28, n. 6(144) (31 dicembre 2020): 15–23. http://dx.doi.org/10.5604/01.3001.0014.3793.
Testo completoAbstract (sommario):
Over the years, a multiplicity of grafting modification techniques have been studied to combine the adsorption and wettability of natural fibres with the capacity of cyclodextrins (CDs) to form inclusion complexes. The fixation of CDs on fibres is possible using crosslinking agents or reactive derivatives of cyclodextrins. Various crosslinking chemicals are suitable to bind the hydroxyl groups of non-reactive cyclodextrins with those of natural fibres by way of spraying, padding, surface coating, and impregnation. Nano-composite dense polymer film could also be formed to anchor the cyclodextrin on the natural fibre surface by the methods of hydrogen binding or covalent binding in sol-gel. A vinyl monomer such as glycidyl methacrylate was used to form polymer coatings due to the pendant epoxy group coupled with the –OH of cyclodextrin and natural fibres. This review also focused on the derivatives of CDs with the reactive group reacting with the hydroxyl groups of natural fibres.
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Vek, Viljem, Angela Balzano, Ida Poljanšek, Miha Humar e Primož Oven. "Improving Fungal Decay Resistance of Less Durable Sapwood by Impregnation with Scots Pine Knotwood and Black Locust Heartwood Hydrophilic Extractives with Antifungal or Antioxidant Properties". Forests 11, n. 9 (22 settembre 2020): 1024. http://dx.doi.org/10.3390/f11091024.
Testo completoAbstract (sommario):
Research Highlights: The antifungal assay confirmed that knotwood extractives of Scots pine inhibit the growth of wood decay fungi. Heartwood extracts of black locust were found to be much stronger free radical scavengers than the extracts of Scots pine. The extracts were deposited in the lumina and on the wall surface of cells in the impregnated sapwood. Impregnation of the sapwood blocks with Scots pine and black locust extracts reduced the fungal decay of wood. Objectives: Hydrophilic extracts of Scots pine knotwood and black locust heartwood were chemically analyzed, tested for antifungal and antioxidant properties and used for impregnation of beech and Scots pine sapwood. Materials and Methods: Scots pine knotwood and black locust heartwood were extracted, and obtained hydrophilic extractives were chemically analyzed. Extracts were analyzed for antifungal properties with the in vitro well-diffusion method. The free radical scavenging activity of wood extracts was measured colorimetrically. The retention of the extracts in the impregnated sapwood blocks was evaluated with microscopy and gravimetry. A decay test was performed with the mini block test. Results: Almost half of both Scots pine knotwood and black locust heartwood hydrophilic extracts obtained were described by phenolic compounds. The extracts were deposited in the lumina of cells and on the cell wall surface. Extractives of Scots pine knotwood had good inhibitory properties against white- and brown-rot fungi. On the other hand, extractives of black locust heartwood were found to be good radical scavengers, better than knotwood extractives of Scots pine. The extracts of Scots pine knotwood and black locust reduced the fungal decay of the tested sapwood blocks. Conclusions: The results of this research show that the less-valued knotwood of Scots pine and heartwood of black locust are a potential source of antifungal and antioxidant agents for bio-based wood preservatives.
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Gankhuyag, Sukhbayar, Dong Sik Bae, Kyoung Lee e Seunghyun Lee. "One-Pot Synthesis of SiO2@Ag Mesoporous Nanoparticle Coating for Inhibition of Escherichia coli Bacteria on Various Surfaces". Nanomaterials 11, n. 2 (22 febbraio 2021): 549. http://dx.doi.org/10.3390/nano11020549.
Testo completoAbstract (sommario):
Silver nanoparticles (Ag NPs) as antibacterial agents are of considerable interest owing to their simplicity, high surface area to volume ratio, and efficient oligodynamic properties. Hence, we investigated the synthesis of silica-supported Ag NPs (SiO2@Ag) as an effective antibacterial agent by using a wet-impregnation method. The formation of SiO2@Ag with Ag NP (5–15 nm diameter) on the silica particle (100–130 nm diameter) was confirmed with transmission electron microscopy (TEM). The study on antibacterial activity was performed in a liquid culture to determine the minimum inhibitory concentration (MIC) against Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) bacteria. Both bacteria are chosen to understand difference in the effect of Ag NPs against Gram-negative (E. coli) and Gram-positive (B. subtilis) bacteria. SiO2@Ag mesoporous nanoparticles had excellent antibacterial activity against E. coli bacteria and fully restricted the bacterial growth when the material concentration was increased up to 1.00 mg/mL. In addition, the obtained material had good adhesion to both steel and polyethylene substrates and exhibited a high inhibition effect against E. coli bacteria.
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Xiao, Zuobing, Wenwen Xu, Jiajia Ma, Yi Zhao, Yunwei Niu, Xingran Kou e Qinfei Ke. "Double-Encapsulated Microcapsules for the Adsorption to Cotton Fabrics". Coatings 11, n. 4 (7 aprile 2021): 426. http://dx.doi.org/10.3390/coatings11040426.
Testo completoAbstract (sommario):
Double-encapsulated microcapsules (DEMs) were prepared and effectively adsorbed onto the cotton fabric surfaces during impregnation without crosslinking agents to obtain functional cotton fabrics. Specifically, Fourier transform infrared spectrometer (FTIR) and confocal laser scanning microscope (CLSM) showed two different molecules (lavender essence and dye indigo) were encapsulated into the microcapsules simultaneously, with loading capacity of 10% and 9.73%, respectively. The spherical shape of DEMs was confirmed by transmission electron microscopy (TEM), confocal laser scanning microscope (CLSM) and average particle sizes were about 617 nm, as measured by dynamic light scattering (DLS). According to the results of IR and X-ray photoelectron spectroscopy (XPS) experiments, DEMs was combined with cotton fabrics by hydrogen bond. The superior thermal stability of microcapsules and functional cotton fabrics was also demonstrated. The adsorption behavior and mechanism of microparticles onto cotton fabrics were further examined by chemical property characterization in combination with adsorption kinetic model. The kinetic adsorption process included three stages: fast adsorption, slow adsorption rate, and adsorption equilibrium. Finally, the good color fastness of the functional cotton fabrics was demonstrated by the tests of rubbing and accelerated laundering. Herein, this study will be beneficial to the development of functional cotton fabrics-based materials.
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Ansanay, Yane, Praveen Kolar, Ratna Sharma-Shivappa, Jay Cheng, Sunkyu Park e Consuelo Arellano. "Pre-treatment of biomasses using magnetised sulfonic acid catalysts". Journal of Agricultural Engineering 48, n. 2 (1 giugno 2017): 117. http://dx.doi.org/10.4081/jae.2017.594.
Testo completoAbstract (sommario):
There is a significant interest in employing solid acid catalysts for pre-treatment of biomasses for subsequent hydrolysis into sugars, because solid acid catalysts facilitate reusability, high activity, and easier separation. Hence the present research investigated pretreatment of four lignocellulosic biomasses, namely Switchgrass (Panicum virgatum L ‘Alamo’), Gamagrass (Tripsacum dactyloides), Miscanthus (Miscanthus × giganteus) and Triticale hay (Triticale hexaploide Lart.) at 90°C for 2 h using three carbon-supported sulfonic acid catalysts. The catalysts were synthesized via impregnating p-Toluenesulfonic acid on carbon (regular) and further impregnated with iron nitrate via two methods to obtain magnetic A and magnetic B catalysts. When tested as pre-treatment agents, a maximum total lignin reduction of 17.73±0.63% was observed for Triticale hay treated with magnetic A catalyst. Furthermore, maximum glucose yield after enzymatic hydrolysis was observed to be 203.47±5.09 mg g–1 (conversion of 65.07±1.63%) from Switchgrass treated with magnetic A catalyst. When reusability of magnetised catalysts were tested, it was observed that magnetic A catalyst was consistent for Gamagrass, Miscanthus × Giganteus and Triticale hay, while magnetic B catalyst was found to maintain consistent yield for switchgrass feedstock. Our results suggested that magnetised solid acid catalyst could pre-treat various biomass stocks and also can potentially reduce the use of harsh chemicals and make bioenergy processes environment friendly.
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Ferro, Fabiane Salles, Julio César Pigozzo, Diego Henrique de Almeida, Felipe Hideyoshi Icimoto, Laurenn Borges de Macedo, Carlito Calil Junior e Francisco Antonio Rocco Lahr. "Nondestructive Evaluation of Timber Columns of a Capela Bridge in the State of São Paulo, Brazil". Advanced Materials Research 778 (settembre 2013): 258–64. http://dx.doi.org/10.4028/www.scientific.net/amr.778.258.
Testo completoAbstract (sommario):
After years of exposure in environmental conditions, the wood is subject to decay by chemical, mechanical, physical and biological agents. Consequently its physical and mechanical properties can be reduced, affecting their use. Timber used in bridge sustention columns is subject to intense decay process, mainly in outcrop area (area in contact to the ground), the most critical situation, because of the best combination of humidity e oxygen, factors that provide wood decay organisms. Decay process can be minimized with preventive maintenance, as wood impregnation with preservatives, before installation of the timber. After wood is installed, a periodical maintenance is necessary to conserve and prolong its life time. Thus, the aim of this study is to evaluate degradation occurred in timber columns used in Capela Bridge sustention, built with mixed system of wood and concrete, after 10-years-old of use. Located in Piracicaba - SP, Brazil, the bridge was made with Corymbia citriodora CCA-treated. The columns strength and degradation conditions were evaluated in 2 points with isntrumented driller. Point A was approximately 1,5 m of the ground and point B was in outcrop area. Instrumented driller results showed that all the columns, in both points, presented good strength and had no degradation level.
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Le Van, Khu, e Thuy Luong Thi Thu. "Preparation of Pore-Size Controllable Activated Carbon from Rice Husk Using Dual Activating Agent and Its Application in Supercapacitor". Journal of Chemistry 2019 (15 gennaio 2019): 1–11. http://dx.doi.org/10.1155/2019/4329609.
Testo completoAbstract (sommario):
Activated carbons prepared from rice husk by chemical activation with dual activation agents, KOH and NaOH, have been studied and characterized by BET, SEM, EDX, FTIR, Boehm titration, Raman, and TGA. It was found that the KOH/NaOH impregnation ratio plays an important role on textural properties of AC. At the same amount of total alkali hydroxide, the KOH/NaOH ratio higher than 1.33 resulted in larger specific surface area (2990∼3043 m2·g−1), microporous surface area (2747∼2831 m2·g−1), and higher micropore volume (1.4250∼1.4316 cm3·g−1). The as-prepared samples exist in the form of spherical-shaped particles with the size ranging from 20 to 60 nm and contain numerous surface functional groups. The as-prepared activated carbons were then assessed as an electrode material of supercapacitor operating in the 0.5 M K2SO4 electrolyte in potential windows of −1.0∼0.0 V. The highest capacitance obtained was 205 F·g−1 at the scan rate of 2 mV·s−1 and 225 F·g−1 at a current density of 0.2 A·g−1. At the scan rate as high as 50 mV·s−1, all the as-prepared activated carbons in this study have the specific capacitance greater than 100 F·g−1.
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Ali Raza, Zulfiqar, Faiza Anwar, Irshad Hussain, Sharjeel Abid, Rashid Masood e Hafiz Shahzad Maqsood. "Fabrication of PLA incorporated chitosan nanoparticles to create enhanced functional properties of cotton fabric". Pigment & Resin Technology 48, n. 2 (21 febbraio 2019): 169–77. http://dx.doi.org/10.1108/prt-11-2017-0088.
Testo completoAbstract (sommario):
PurposeThis study aimed to present fabrication of novel poly(lactic acid) (PLA) mediated chitosan nanoparticles (CNPs) and their impregnation on cotton fabric for enhanced antibacterial and physical properties.Design/methodology/approachThe PLA-CNPs were characterized using scanning electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared (FTIR) spectroscopy and zeta size analysis. The prepared PLA-CNPs were impregnated on cotton fabric via pad-dry-cure method. The finished cotton fabric was then characterized for its antibacterial activity, functional and other physical textile properties.FindingsThe spectral and optical properties demonstrate that the NPs expressed spherical morphologies with an average particle diameter of 88.02 nm. The antibacterial activity of treated fabrics ranged between 75 and 90 per cent depending on the concentration of PLA-CNPs.Practical implicationsBecause of enhanced awareness and desire for ecofriendly products, the use of sustainable and functional textiles is increasing day by day. For the said purpose, industries are using different chemical treatments to achieve desired end functionality. Currently, different synthetic antibacterial agents are in practice, but they lack sustainable approach to save the environment. In this study, the researchers have developed PLA mediated CNPs for sustainable antibacterial and physical properties of treated cotton fabric.Originality/valueTo the best of the authors’ knowledge, this is first attempt to fabricate PLA-incorporated CNPs for application on cotton fabric followed by a detailed characterization.
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Boccarusso, Luca, Dario De Fazio e Massimo Durante. "Production of PP Composites Reinforced with Flax and Hemp Woven Mesh Fabrics via Compression Molding". Inventions 7, n. 1 (21 dicembre 2021): 5. http://dx.doi.org/10.3390/inventions7010005.
Testo completoAbstract (sommario):
Hemp and flax fibers are among the most interesting vegetable fibers that can be used to reinforce polymeric matrices. In line with the global environmental requests, the use of these fibers especially coupled with thermoforming polymers are increasing more and more in order to expand their applications and replace synthetic fibers and thermosetting plastics. However, one of the major limitations of vegetable fibers is their poor adhesion with polymeric matrices that is often overcome by fibers chemical treatments or by using coupling agents within the matrix. Aiming to produce polypropylene (PP) bio composite laminates reinforced by hemp and flax fibers without additional process steps, this paper deals on the study of their production via the compression molding technique by using woven fabrics characterized by a large mesh size able to ensure a mechanical anchoring between fibers and matrix. Two different forming strategies that differ in the time required for reaching the maximum values of compression pressure and in the dwelling time at this value were used in order to investigate how the yarn impregnation was affected by them. To expand the applications of composites under investigation, tensile, bending, Izod, heat deflection temperature (HDT) and bearing tests were carried out. The results highlighted how the use of a waiting time before the reaching of the maximum moulding pressure allowed a better matrix flow within the vegetable yarn leading to higher mechanical performances.
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Stoof, Cathelijne R., Jasper H. J. Candel, Laszlo A. G. M. van der Wal e Gert Peek. "Soil lacquer peel do-it-yourself: simply capturing beauty". SOIL 5, n. 2 (9 luglio 2019): 159–75. http://dx.doi.org/10.5194/soil-5-159-2019.
Testo completoAbstract (sommario):
Abstract. Visualization can greatly benefit understanding of concepts and processes, which in soil science and geology can be done using real-life snapshots of soils and sediments in lacquer peels and glue peels. While it may seem complicated, anyone can make such a soil peel for use in classrooms, public places, homes, and offices for teaching, outreach, decoration, and awareness. Technological development has considerably simplified the making of soil peels, but this methodological innovation has not been described in the literature. Here, we report on a thoroughly tested and simple method for taking peels of sandy soils using readily available tools and materials. Our method follows the main previously published steps of preparing a soil face, impregnating the soil face with a fixation agent in the field, extracting the resulting peel, and mounting it on a wooden panel. Yet instead of using lacquers and thinning agents, we use strong though flexible contact adhesive (glue), which has the major advantage that it no longer requires use and mixing of toxic chemicals in the field or reinforcement of the peel to prevent breaking. Moreover, the preservation potential is much higher than with the old method. This new twist to old methods makes creation of soil peels safer, simpler, and more successful, and thereby a true DIY (do-it-yourself) activity. The resulting increased accessibility of making soil and sediment peels can benefit research, teaching, and science communication and can thereby bring the value and beauty of the ground below our feet to students, schools, policy makers, and the general public.
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Molero, Esther, Antonio Javier Sanchez-Herencia, Roberto G. das Neves, Elena Gordo e Begoña Ferrari. "Shaping Strategies for Porous Ti Fabrication throughout Colloidal Chemistry". Key Engineering Materials 704 (agosto 2016): 406–12. http://dx.doi.org/10.4028/www.scientific.net/kem.704.406.
Testo completoAbstract (sommario):
Aimed by reducing the total cost of products, powder metallurgy (PM) processing of Ti is a subject of high interest. However, using of conventional PM techniques presents difficulties due to the intrinsic characteristics of Ti, like low strain ability, and high reactivity, which lead to low compressibility. Moreover, Ti powders with small particle size are difficult to process by conventional PM techniques as they present a lower compressibility and also a poor flowability. On the other hand, the colloidal processing has been used for long in ceramics to achieve green bodies with high densities, complex shapes and homogeneous microstructures, but they are rarely used to shape metal powders because of its high density and high surface reactivity. However, the possibility to process fine particles makes these techniques interesting for metals with low density like Ti.The colloid-chemistry control of metallic powders in aqueous slurries is proposed as a way to prepare Ti porous parts with small particle size, throughout the formulation of aqueous slurries with solid contents as high as 50 vol.%. The chemical and chemical-physic stability of Ti powders 10 μm in size was determined by measuring the zeta potential as a function of pH, and dispersant concentration, while the later optimization of Ti slurries and their adequation for the use of different colloidal techniques, were studied in terms of rheology and the addition of the processing additives, such as gel or foaming agents. Techniques such as thermal gelling, foaming, and impregnation of exo-templates or robocasting were used to build Ti parts with random and/or tailored macroporosity. The shaped pieces made on Ti were sintered in vacuum at 1100 oC for 30 minutes, and their microstructure and mechanical properties were determined and compared with dense materials shaped by combining PM and colloidal techniques in previous works
34
Konstantinova, N. I., e A. V. Zuban. "On the Requirements for Conducting Fire Protection of Textile Materials". Occupational Safety in Industry, n. 1 (gennaio 2022): 57–62. http://dx.doi.org/10.24000/0409-2961-2022-1-57-62.
Testo completoAbstract (sommario):
Currently, there is no normative support and regulation of the use of fire protection for textiles at the facilities. In the regulatory documents, including in EAEU TR 043/2017 «On the requirements for fire safety and fire extinguishing means», there is no regulation for the development of technical documentation for them, and the procedure for confirming the conformity of flame-retardants for textile materials as means of ensuring their fire safety. Comparative studies of the flammability of curtain, upholstery furniture fabrics, protective work clothes, canopies and tents treated with various flame-retardants that do not reduce operational properties were carried out using standard evaluation methods. It is shown that the achievement of the effect of fire protection of fabrics with the same impregnation technology occurs at different concentrations of agents depending on the composition of chemical fibers and test methods. When using an efficient fire- retardant to obtain a flame-retardant fabric containing 100 % polyester, it was not possible to achieve a positive result of fire protection. Efficient surface fire protection of the mixed fabrics with a polyester fiber content of 60 % or more using compositions based on the inorganic salts of phosphoric acid without losing their decorative appearance is not possible, moreover, these compositions do not ensure resistance to washing. It is concluded that for conducting fire protection of textile materials, it is required to develop technical requirements for fire protection means, which should consider their efficiency of action, method of application and consumption, fabric characteristics, their functional purpose and field of application, as well as regulate methods for assessing flammability, procedures for confirming compliance with fire-safe use.
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Korolchenko, O. N., S. G. Tsarichenko e N. I. Konstantinova. "Flammability properties of fire-retardant timber". Pozharovzryvobezopasnost/Fire and Explosion Safety 30, n. 2 (15 maggio 2021): 23–34. http://dx.doi.org/10.22227/pvb.2021.30.02.23-34.
Testo completoAbstract (sommario):
Introduction. At present, the house-building industry, that produces timber structures, is in the process of sufficiently intensive development; however, high flammability of wood is the factor that restrains widespread use of timber in construction. The purpose of this work is to optimize the conditions of application of fire-retardant timber in the construction industry. The co-authors believe that the following problems are to be solved to attain this objective:● a comparative analysis of the fireproofing efficiency of several fire-proofing agents applied to different species of wood;● determination of the character of influence produced by fire proofing agents on fire retardant properties of wood.Methods of research. The fire proofing efficiency of sample compositions designated for wood was measured in compliance with the benchmark testing method specified in GOST R 53292 (p. 6.2). Experiments were launched pursuant to the methodology and with the help of measurement instruments specified in GOST 30244–94 (Method 2) to study the extent of the pine-tree timber flammability suppression. Critical values of thermal loads that may trigger inflammation and flame propagation in timber structures, that can be described using values of the critical surface density of the heat flow, were determined pursuant to GOST 30402–96 and GOST R 51032–97. The toxicity of combustion products and the smoke generation ability of fire-retardant pine-tree samples was assessed using standard methods and measurement instruments pursuant to GOST 12.1.044–89 (paragraphs 4.18 and 4.20).Research results and discussion. Biological flame retardants, integrated biological flame retardants that also ensure moisture protection, intumescent coatings, lacquers and varnishes that are ready for use and labelled as having group I and II fire-retardant efficiency pursuant to GOST R 53292, were studied in the course of this research project. The co-authors have identified that the mass loss by all fire-retardant compositions is below 9 %, if applied to samples of larch and oak-tree timber, same as if it were applied to standard samples of pine-tree timber.The findings of the experiment conducted to assess the flammability, ignitibility, flame propagation, smoke generation ability and toxicity of combustion products have proven the maximal efficiency of the composition designated for full-cell pressure impregnation of timber that ensures the properties of the material labelled as G1, V1, RP1, T2, D2.Conclusions. Hence, the research results have enabled the co-authors to assess the discrepancy between average mass loss values demonstrated by the samples of different species of timber (alder, linden, pine-tree, larch, and oak-tree).The comprehensive study of flammability properties of timber, treated by compositions that vary in their chemical composition and mode of action of the fire proofing agent, enabled the co-authors to identify the impact produced by versatile fire-proofing agents on different flammability properties of pine-tree timber with regard taken of the fire-safe use of construction materials and constructions of buildings and structures.
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Li, Peng, Lingxue Liu, Sheng Huang, Yonghong Zhang, Jianhua Xu e Zhiqiang Zhang. "Anti-cancer Effects of a Neutral Triterpene Fraction from Ganoderma lucidum and its Active Constituents on SW620 Human Colorectal Cancer Cells". Anti-Cancer Agents in Medicinal Chemistry 20, n. 2 (24 aprile 2020): 237–44. http://dx.doi.org/10.2174/1871520619666191015102442.
Testo completoAbstract (sommario):
Background: Ganoderma lucidum (Leyss. ex Fr.) Karst. (G. lucidum, GL) belongs to the family of Ganodermataceae (Basidiomycetes), and possesses activities including antitumor, antimicrobial, antiviral, and antiaging activities. Triterpenoids are typical chemical constituents in G. lucidum, and play an important role in the anti-cancer effects. According to the substituent group at the carbon 26 position, GL total triterpenes fraction can be divided into two types, Neutral Triterpene Fraction (NTF) and an Acidic Triterpene Fraction (ATF). The anti-cancer effects of total triterpenes fraction and total acidic triterpene fraction extracted from G. lucidum have been widely known in vivo and in vitro, whereas few have focused on total neutral triterpene fraction. Objective: The aim of this study was to evaluate the anti-cancer effects of NTF extracted from G. lucidum in vitro and in vivo and explore its anti-cancer active constituents on SW620 human colorectal cancer cells. Methods: NTF and ATF were extracted from the dry fruiting body of G. lucidum by impregnation method with 90% ethanol, and further isolated by using alkaline extraction and acid precipitation method. The total triterpenoid content of NTF and ATF was determined by using ultraviolet-visible spectrophotometry. The cytotoxic effects on human colon cancer cells SW480, SW620, SW1116, and mouse embryonic fibroblast cell line NIH3T3 were evaluated by using the MTT method. The anti-cancer activity of NTF in vivo was evaluated in Athymic nude mice against SW620 cells. An activity-guided separation and purification process were used to identify the anti-cancer active constituents of NTF by column and preparative high-performance liquid chromatography. Structures of the constituents were confirmed by 1H-NMR, 13C-NMR and MS. Protein expression was performed by Western blotting. Results: The percentage of total triterpenoids was 46.7% and 57.6% in ATF and NTF, respectively. Both fractions could reduce the viability of SW480, SW620, and SW1116 cells in vitro, whereby NTF exhibited a stronger effect than ATF. NTF markedly inhibited the growth of SW620 cell xenografts in mice at doses (250, 500mg/kg) during the treatment. Furthermore, a new garnoderic alcohol, named as ethyl ganoderate A and eight known ganoderic alcohols were isolated and identified from NTF by a bioassay-guided separation process. All of these compounds possessed anti-cancer activities against SW620 cells in vitro. As a representative ganoderma alcohol, ganodermanondiol significantly reduced the viability of SW620 cells through the induction of apoptosis, which was associated with the upregulated the levels of cleaved-poly (ADP-ribose) polymerase (PARP), cleaved-caspase-3, and -9. In addition, ganodermanondiol showed low cytotoxic activity against normal NIH3T3 cells. Conclusion: NTF are potential anti-cancer agents against colon cancer and the active constituents may be ganoderic alcohols whose inhibitory mechanism of anti-cancer action may be related to the activation of a mitochondrial- dependent pathway.
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Lee, Butrand I., e L. L. Hench. "Silicon Carbide From Organosilanes and Application in Silica Gel Glass Composites". MRS Proceedings 73 (1986). http://dx.doi.org/10.1557/proc-73-815.
Testo completoAbstract (sommario):
ABSTRACTSeveral organosilanes were crosslinked and pyrolyzed to produce silicon carbide (SiC). Use of chemical crosslinking agents required lower temperatures and shorter times for curing and increased SiC char yields. Impregnating the silanes into sol-gel derived silica monoliths followed by crosslinking and pyrolysis resulted in hard and tough SiC/SiO2 composite bodies.
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Zhang, Jing, Hairu Long e Peihua Zhang. "Structure and characterization of carbonized cotton knitted fabric". Textile Research Journal, 20 aprile 2022, 004051752210936. http://dx.doi.org/10.1177/00405175221093659.
Testo completoAbstract (sommario):
Carbonized cotton fabrics have been used in the preparation of wearable sensors. However, there are few studies on the carbonization structure and properties of carbonized cotton fabric. This work provided a practical and effective method for the preparation of carbonized cotton knitted fabrics. The effects of impregnating agents and pre-oxidation on the carbonization structure and performances of the cotton knitted fabric were investigated systematically for the first time. Thermal gravimetry analysis revealed that cotton knitted fabric impregnated with 10% (NH4)2HPO4 had a higher carbonized yield of cotton knitted fabric than that with 5%, which was followed by 10% NH4H2PO4, and the worst was 10% (NH4)2SO4. The results also showed that the carbonized yield of cotton knitted fabric was enhanced considerably at 900°C for 120 min after impregnation with 10% (NH4)2HPO4 and pre-oxidation at 240°C for 60 min. The integrity of the cotton knitted fabric was maintained after carbonization. Scanning electron microscopy showed that the natural turn of carbonized cotton fiber was deepened after being impregnated with 10% (NH4)2HPO4 and pre-oxidized at 240°C for 60 min. With the increase of carbonization temperature, C-O and C-H were destroyed, and C=C bonds were formed. The amorphous carbon interlayer was created after carbonization. The structural order of these carbonized cotton fibers was improved with the enhancement of temperature. Pre-impregnation agent treatment and pre-oxidation greatly heightened the carbonized yield of cotton knitted fabric, maintained the integrity of the carbonized cotton fiber, and then increased the electrical conductivity of the carbonized cotton knitted fabric.
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Acevedo, Sergio, Liliana Giraldo e Juan Carlos Moreno-Piraján. "Adsorption of CO2 onto Activated Carbons Prepared by Chemical Activation with Metallic Salts". International Journal of Chemical Reactor Engineering 15, n. 6 (9 dicembre 2017). http://dx.doi.org/10.1515/ijcre-2017-0029.
Testo completoAbstract (sommario):
Abstract Activated carbons are obtained by chemical activation of African Palm shells (Elaeis guineensis) with different impregnating agents, i. e. magnesium chloride (MgCl2) and calcium chloride (CaCl2) aqueous solutions at different concentrations (3, 5 and 7 % w/v) and temperatures (between 773 and 1073 K), in order to assess their influence on the development of the porosity. The activated carbons prepared are characterized in terms of both textural and chemical properties. The activated carbons have a surface area and a pore volume ranging between 19 and 501 m2.g−1 and 0.03–0.29 cm3.g−1, respectively. Based on the obtained results, the samples with higher surface area and pore volume (i. e. those impregnated with MgCl2 and CaCl2 solutions and thermally treated at 1073 K) are selected to evaluate the adsorption capacity and affinity for CO2. CO2 adsorption capacity varies between 1.78 and 2.95 mmolCO2.g−1 at 273 K and low pressure, and the activated carbon impregnated with the solution of MgCl2 3% and activated at 1073 K (i. e. ACMg3-1073) showed the best performances. Finally, the kinetic results show that adsorption rate for sample ACMg3-1073 is enhanced by its micro-mesoporous nature, being the access routes to the micropores larger.
40
Acevedo, Sergio, Liliana Giraldo e Juan C. Moreno-Piraján. "Adsorption of CO2 onto Activated Carbons Prepared by Chemical Activation with Metallic Salts". International Journal of Chemical Reactor Engineering 15, n. 6 (20 dicembre 2017). http://dx.doi.org/10.1515/ijcre-2017-0198.
Testo completoAbstract (sommario):
Abstract This article has been retracted due to honest error by the author. For further information, please see https://doi.org/10.1515/ijcre-2017-9198. Activated carbons are obtained by chemical activation of African Palm shells (Elaeis guineensis) with different impregnating agents, i. e. magnesium chloride (MgCl2) and calcium chloride (CaCl2) aqueous solutions at different concentrations (3, 5 and 7 % w/v) and temperatures (between 773 and 1073 K), in order to assess their influence on the development of the porosity. The activated carbons prepared are characterized in terms of both textural and chemical properties. The activated carbons have a surface area and a pore volume ranging between 19–501 m2.g−1 and 0.03–0.29 cm3.g−1, respectively. Based on the obtained results, the samples with higher surface area and pore volume (i. e. those impregnated with MgCl2 and CaCl2 solutions and thermally treated at 1073 K) are selected to evaluate the adsorption capacity and affinity for CO2. CO2 adsorption capacity varies between 1.78 and 2.95 mmolCO2.g−1 at 273 K and low pressure, and the activated carbon impregnated with the solution of MgCl2 3 % and activated at 1073 K (i. e. ACMg3-1073) showed the best performances. Finally, the kinetic results show that adsorption rate for sample ACMg3-1073 is enhanced by its micro-mesoporous nature, being the access routes to the micropores larger.
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Goud, Sai Chandra, Prerna Kataria, Pradeep Shukla, Gaurav Malhotra, Varun Dahiya e Mona Dagar. "COMPARATIVE EVALUATION OF THE EFFICACY OF DIODE LASER, GLUMA DESENSITIZER AND DESENSITIZING MOUTH RINSE IN THE TREATMENT OF DENTINE HYPERSENSITIVITY – CLINICAL STUDY". International Journal of Medical and Biomedical Studies 5, n. 1 (5 gennaio 2021). http://dx.doi.org/10.32553/ijmbs.v5i1.1614.
Testo completoAbstract (sommario):
Introduction: Dentine hypersensitivity is characterized by acute, sharp pain arising from the exposed dentine, most commonly in response to thermal, tactile, or chemical stimuli, and which cannot be linked to any other pathological changes in the tooth or the environment. Therapy uses various impregnating agents in the form of solutions or gels and, in more recent times, lasers. Gluma Desensitizer, Desensitizing mouthrinse has been used previously in a dentifrice or gel to alleviate dentinal hypersensitivity.
Aim: To compare the efficacy of Diode laser, Gluma desensitizer and desensitizing mouth rinse in the treatment of dentine hypersensitivity.
Materials and Methods: The study contained 60 individuals (42 males and 18 females) of dentinal hypersensitivity. There were three groups in the study i.e., patients treated with laser, Gluma Desensitizer and Desensitizing mouth rinse. Before starting any treatment, the hypersensitivity was checked with the help of cold air blast and probe test according to VAS (Visual analog scale) the responses were evaluated from the patients.
Results: Group I (Laser) showing the highly significant results compared to group 2 (Gluma desensitizer) and group 3 desensitizing mouth rinse (3% Potassium Nitrate) in decreasing the dentinal hypersensitivity.
Keywords: dentine hypersensitivity, desensitizing agent, diode laser, laser therapy. Gluma Desensitizer; mouth rinses
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Chirkova, Jelena, Ingeborga Andersone, Ilze Irbe, Baiba Spince e Bruno Andersons. "Lignins as agents for bio-protection of wood". Holzforschung 65, n. 4 (1 giugno 2011). http://dx.doi.org/10.1515/hf.2011.092.
Testo completoAbstract (sommario):
Abstract Pinewood was modified by vacuum impregnation with various aqueous lignin solutions of low concentration (0.5– 1.0%) and its decay resistance was tested by the standard procedure EN 113. Five lignin types were tested against three brown rot and one white rot fungi. The bio-durability of wood was considerably increased by the treatment. The highest effect of modification was for alkali, kraft, hydrolysis lignins and industrial lignosulfonate, when mass losses of wood for brown-rot fungi were negligible. The effect of the modification with certified lignosulfonates was insignificant. Chemical analysis revealed that phenols, which are leached from lignin and are adsorbed by wood in the impregnation process, could act as a biocide. The hydrophilic properties of wood either did not change (certified lignins) or were enhanced because of some change in the pore structure (industrial lignins). Further tests are needed to verify the positive effects of this technologically simple and environmentally friendly treatment.
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Kiani, Sidra Shaoor, Amjad Farooq, Masroor Ahmad, Naseem Irfan, Mohsan Nawaz e Muhammad Asim Irshad. "Impregnation on activated carbon for removal of chemical warfare agents (CWAs) and radioactive content". Environmental Science and Pollution Research, 21 settembre 2021. http://dx.doi.org/10.1007/s11356-021-15973-1.
Testo completo
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Lopez, Ma Michelle L., Rui M. S. C. Morais e Alcina M. M. B. Morais. "Flavonoid enrichment of fresh-cut apple through osmotic dehydration-assisted impregnation". British Food Journal ahead-of-print, ahead-of-print (26 ottobre 2020). http://dx.doi.org/10.1108/bfj-03-2020-0176.
Testo completoAbstract (sommario):
PurposeInclusion of bioactive compounds in food products is promising for developing novel functional food products. The feasibility of incorporating flavonoids and low-calorie sugar substitutes in fresh-cut apple through osmotic dehydration (OD) was investigated.Design/methodology/approachThe impregnation of quercetin and fisetin in apple cubes was tested. The effects of different osmotic agents, sucrose and sorbitol:mannose, on the water loss (WL) and sugar gain of the samples were studied at 25 and 40 °C for eight hours.FindingsTemperature was a significant factor in the mass transfer kinetics, that is to say, higher temperatures resulting in higher rates. The molecular weight of the solutes in the osmotic solution also affected the OD kinetics and flavonoids uptake, as well as the physico-chemical quality.Originality/valueOverall, the results indicate that OD using alternative low-calorie and health-promoting solutes can be an effective treatment to simultaneously enrich fresh-cut apples with senolytic flavonoids, therefore presenting a great potential for a novel functional food product.
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Heimann, Manuel, Klaus Friedel Ortega e Malte Behrens. "Co3O4/BiVO4 Heterostructures for Photochemical Water Oxidation: The Role of Synthesis Parameters and Preparation Route for the Physico-Chemical Properties and the Catalytic Activity". Zeitschrift für Physikalische Chemie, 19 dicembre 2019. http://dx.doi.org/10.1515/zpch-2019-1477.
Testo completoAbstract (sommario):
Abstract The synthesis conditions of the semiconductor BiVO4 have marked influence on its physicochemical and photocatalytic properties. In this work, a pH-controlled co-precipitation route was systematically investigated. Special attention was paid to the pH value during co-precipitation and co-precipitate post-treatment. In a sacrificial photocatalytic water oxidation test, the highest activity was observed for a sample precipitated at pH = 1 and 70 °C, which was post treated at 600 °C in air for 3 h after washing and drying. The activity was further improved by another 90% by the addition of the Co3O4-based co-catalyst. Good synergy between semiconductor and co-catalyst was obtained for the deposition of pre-formed nanoparticles at a loading of 0.1 w% (physical impregnation). The effects of different synthesis conditions of the semiconductor and impregnation method for the co-catalyst on the structure, morphology and optical properties of the catalysts were investigated by PXRD, SEM, UV-vis spectroscopy, and TEM, while the water oxidation activity was compared in the dark and with the aid of visible light using cerium (IV) or silver (I) as sacrificial agents, respectively, with the aim of establishing structure-activity correlations. The roles of semiconductor particle anisotropy and co-catalyst particle distribution for optimal photo-activity in the oxygen evolution reaction are discussed.
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Toprak, Atakan, e Turkan Kopac. "Carbon Dioxide Adsorption Using High Surface Area Activated Carbons from Local Coals Modified by KOH, NaOH and ZnCl2 Agents". International Journal of Chemical Reactor Engineering 15, n. 3 (11 gennaio 2017). http://dx.doi.org/10.1515/ijcre-2016-0042.
Testo completoAbstract (sommario):
Abstract Activated carbons of various features were produced by the impregnation of local coal samples that were taken from Kilimli region of Zonguldak (Turkey) with chemical agents KOH, NaOH and ZnCl2 at different temperatures (600–800 °C) and concentrations (1:1–6:1 agent:coal), for their evaluation in CO2 adsorption studies. BET, DR, t-plot and DFT methods were used for the characterization of carbon samples based on N2 adsorption data obtained at 77 K. The pore sizes of activated carbons produced were generally observed to be in between 13–25 Å, containing highly micropores. Mesopore formations were higher in samples treated with ZnCl2. The highest value for the BET surface area was found as 2,599 m2 g−1 for the samples treated with KOH at 800 °C with a KOH to coal ratio of 4:1. It was observed that the CO2 adsorption capacities obtained at atmospheric pressure and 273 K were considerably affected by the micropore volume and surface area. The highest CO2 adsorption capacities were found as 9.09 mmol/g (28.57 % wt) and 8.25 mmol g−1 (26.65 % wt) for the samples obtained with KOH and NaOH treatments, respectively, at ratio of 4:1. The activated carbons produced were ordered as KOH>NaOH>ZnCl2, according to their surface areas, micropore volumes and CO2 adsorption capacities. The low-cost experimental methods developed by the utilization of local coals in this study enabled an effective capture of CO2 before its emission to atmosphere.