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1
Burkhardt, A. E. "Chemical assays--new opportunities." Clinical Chemistry 33, no. 9 (September 1, 1987): 1574–78. http://dx.doi.org/10.1093/clinchem/33.9.1574.
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Abstract The acceptance of the solid-phase format in various areas of clinical chemistry is the consequence of the advantages of this test format, which include stability of the reagents, unitized packaging, convenient and small instruments, and minimal preparations by users before testing. Overall, these advantages provide very convenient tests. Future successful uses of solid-phase reagents depend upon how well these features meet the needs of the users. Needs for systems to be used in the decentralized laboratory include even less cost, even more convenience, and improved quality control. Needs for home testing include convenient tests with clinically useful accuracy, improved quality control, and improved recording systems to overcome user bias in recording results. New solid-phase technologies being developed include noncolorimetric systems suitable for use with miniature probes, for in vitro or in vivo use, and spectrophotometric systems for determinations of analytes directly in capillaries of the skin without invasive sampling.
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Yesentai, D. E. "Influence of anti-ice chemicals on reduction of strength properties of cement concrete." Bulletin of Kazakh Leading Academy of Architecture and Construction 79, no. 1 (March 30, 2021): 216–21. http://dx.doi.org/10.51488/1680-080x/2021.1-29.
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In this article were analyzed the problems of liquidation winter slipperiness on the roads with hard surface using chemical reagents. The article analyzes the results of tests using traditional (chloride) and non-traditional chemical reagents and their influence on the strength properties of cement concrete.
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Bach, Sylvie, Mohamed Naceur Belgacem, and Alessandro Gandini. "Hydrophobisation and densification of wood by different chemical treatments." Holzforschung 59, no. 4 (July 1, 2005): 389–96. http://dx.doi.org/10.1515/hf.2005.064.
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Abstract Samples of Pinus sylvestris were treated with different reagents bearing isocyanate, carboxylic anhydride or oxirane functions to induce reaction with the OH groups of the various components of wood. Conditions were optimised to achieve maximum grafting. When the reagents also carried a polymerisable function, a monomer (styrene or methyl methacrylate) was incorporated into the wood morphology after the derivatisation reaction. Subsequent radical polymerisation produced chemical incorporation of some of the resulting macromolecules. The properties of the doubly modified samples were assessed using a wide variety of tests. Both the hydrophobic character and the density increased considerably, suggesting improved lifetime and extended domains of application.
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Grélot, A., C. Machinal, K. Drouet, A. Tazi-Pain, J. C. Schrotter, A. Grasmick, and S. Grinwis. "In the search of alternative cleaning solutions for MBR plants." Water Science and Technology 58, no. 10 (November 1, 2008): 2041–49. http://dx.doi.org/10.2166/wst.2008.759.
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The objective of the study was to identify alternative cleaning reagents to chlorine for membrane permeability regeneration in MBR applications. Indeed, chlorine is prohibited in some countries because of the formation of by-products such as THM. The study was focused on the comparison of ten cleaning reagents performances and in particular on their ability to remove irreversible fouling. The tests were carried on with the A3 Water Solutions' Maxflow membrane (flat sheet membrane). A specific experimental protocol was defined at lab scale to develop an irreversible fouling by filtering sludge supernatant. The more promising reagents at lab scale were then tested on the A3 membrane continuously immersed in a MBR pilot plant functioning under typical biological conditions (MLSS = 11 g/l; SRT = 28days). A full scale test was finally performed with hydrogen peroxide, one of the best reagents. Chlorine was taken as reference for all performed tests. The cleaning performances of the selected reagents were different at the different scales, probably due to the difficulty to obtain an irreversible membrane fouling at larger scales. This testing procedure will be reproduced with other membrane materials to have a better understanding of interactions between irreversible fouling, material nature and chemical reagents.
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Berth, Mario, and Eugene Bosmans. "Prevention of Assay Interference in Infectious-Disease Serology Tests Done on the Liaison Platform." Clinical and Vaccine Immunology 15, no. 5 (March 12, 2008): 891–92. http://dx.doi.org/10.1128/cvi.00012-08.
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ABSTRACT Immunoassay interference causing unexpected reactive results in magnetic-microparticle-based assays was detected. A systematic evaluation of Liaison Epstein-Barr virus immunoglobulin M showed that 5% of the positive results (0.4% of tested samples) could be explained by such interference. Adding chemical blocking reagents (polyvinylpyrrolidone and polyvinyl alcohol) to the assay buffers partially prevented this phenomenon.
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Barkovskii, N. V. "Identification of Fe (IV) in oxides by chemical test methods." Industrial laboratory. Diagnostics of materials 86, no. 6 (June 22, 2020): 5–13. http://dx.doi.org/10.26896/1028-6861-2020-86-6-5-13.
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A comparative analysis of the behavior of oxides containing Fe (III) and Fe (IV) in redox reactions with organic and inorganic reagents has been carried out. SrFeO3-x oxide obtained by solid-phase synthesis from SrCO3 and Fe2O3 has been an object to develop test methods. It has been shown that Fe (IV) exhibits the properties of a stronger oxidizer than Fe (III), thus providing a set of reagents which enable identification of Fe (IV): hydrobromic acid, Fe2+ complex with V (IV), and Mn (II) salts, and organic reagents, namely, amines (diphenylamine, o-tolidine, benzidine) and dyes (methyl red). Potentiometric method proved stronger oxidative properties of Fe (IV) compared to Fe (III) revealed in different character of changes in EMF during dissolution of the corresponding oxides in HCl. SrFeO3–x oxide does not oxidize Mn (II) to Mn (VII), Cr (III) to Cr (VI), Ce (III) to Ce (IV) in acidic media, and Cu (II) to Cu (III) in alkaline media. Since the oxide under study oxidize Cl– = 1.3583 V) and Br– = 1.087 V) ions to the corresponding halogens, but does not oxidize Mn2+ to = 1.51 V), an estimated value of the standard redox potential is ~1.4 V. We have developed for the first time a system of analytical tests for differentiation of Fe (IV) and Fe (III) which can provide monitoring of the synthesis of complex oxides and phase formation in the systems containing iron, alkali and alkaline earth metals.
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Eksperiandova, L. P., S. V. Khimchenko, N. A. Stepanenko, and I. B. Shcherbakov. "Simple Instrumental and Visual Tests for Nonlaboratory Environmental Control." Journal of Analytical Methods in Chemistry 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/1270629.
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Proposed are simple and available techniques that can be used for rapid and reliable environmental control specifically of natural water by means of instrumental and visual tests in outdoor conditions. Developed are the chemical colorimetric modes for fast detection of socially dangerous trace impurities in water such as Co(II), Pd(II), and Rh(III) as well asNO2--ions and Fe(III) serving as model impurities. Application of portable digital devices and scanner allows estimating the color coordinates and increasing the accuracy and sensitivity of the tests. The combination of complex formation with preconcentration of colored complexes replaces the sensitive but time-consuming and capricious kinetic method that is usually used for this purpose at the more convenient and reliable colorimetric method. As the test tools, the following ones are worked out: polyurethane foam tablets with sorbed colored complexes, the two-layer paper sandwich packaged in slide adapter and saturated by reagents, and polyethylene terephthalate blister with dried reagents. Fast analysis of polyurethane foam tablets is realized using a pocket digitalRGB-colorimeter or portable photometer. Express analysis of two-layer paper sandwich or polyethylene terephthalate blister is realized by visual and instrumental tests. The metrological characteristics of the developed visual and instrumental express analysis techniques are estimated.
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Kricka, Larry J., and Jason Y. Park. "Dry Reagent Tests in the 1880s—Dr Pavy’s Pellets and Dr Oliver’s Papers." Journal of Applied Laboratory Medicine 6, no. 4 (June 1, 2021): 1025–31. http://dx.doi.org/10.1093/jalm/jfab023.
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Abstract Background In the 1880s, concern over the inconvenience of hazardous chemical solutions used for bedside urinalysis sparked an interest in the development of dry reagents for a range of common urine tests. Content This article examines the history of Dr Pavy’s Pellets and Dr Oliver’s Papers, 2 different dry reagent systems developed in the 1880s for bedside urine testing. It sets these developments in the context of the earlier dry chemistry work (e.g., indicator papers) and the subsequent work that led to modern day reagent tablets and dipstick devices. Summary Tests based on dry reagents can be traced back to the 1st century, but active development, in the form of indicator papers, dates from the 1600s. In the 1880s, spurred by dissatisfaction with liquid-based bedside urine testing among clinicians, Dr Frederick William Pavy and Dr George Oliver developed dry reagent tests, based on pellets (Dr Pavy’s Pellets) and chemically impregnated papers (Dr Oliver’s Papers) for urine sugar and urine albumin. These reagents were commercialized by a number of companies and provided in convenient cases (Physician’s Pocket Reagent Case). Eventually, these tests lost popularity and were replaced by the type of tablets and dipsticks developed by both Eli Lilly, and the Ames Division of Miles Laboratories (subsequently Bayer, and currently Siemens Healthineers) during the 1940s and 1950s.
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Rzhevskaya, Elena V., Vladlena V. Davydova, and Igor V. Dolbin. "Study of the Influence of the Chemical Resistance of Polyphenylenesulphone from Radel on Mechanical Properties." Key Engineering Materials 899 (September 8, 2021): 245–52. http://dx.doi.org/10.4028/www.scientific.net/kem.899.245.
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The paper presents the results of a study of the chemical resistance and mechanical properties of polyphenylene sulfone manufactured by Solvay, Radel brand, obtained by injection molding. Chemical resistance was investigated in short-term tests (24 hours duration), standard (7 days) and long-term (16 weeks). The mechanics of PPSU samples after exposure to chemical reagents is presented. It was revealed in what chemical environments and how much the mechanical properties of polyphenylene sulfone are preserved.
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Monette, Frédéric, François G. Brière, Michel Létourneau, Marc Duchesne, and Robert Hausler. "Traitement des eaux usées par coagulation-floculation avec recirculation des boues chimiques : Influence des réactifs." Canadian Journal of Civil Engineering 27, no. 4 (August 1, 2000): 719–34. http://dx.doi.org/10.1139/l00-046.
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Three series of tests were carried out at laboratory and pilot levels to examine the functions of reagents (coagulant, flocculant, sludge) involved in a coagulation-flocculation process with chemical sludge recycling. Results showed that the recycled sludge participates favourably in the process. The gains in efficiency are particularely significant for lower coagulant concentrations when flocculant concentration is not limitative. The pollutant removal increases with the sludge recycling load but seems reversible and dependent on coagulant concentration. Results also revealed the advantages of recycling sludge before injecting coagulant. To decrease the total chemical costs at a wastewater treatment plant, the strategy must focus on diminishing the coagulant concentration and increasing the flocculant concentration while maintaining a sufficient recycling sludge load to ensure gains in efficiency.Key words: recycling, sludge, preformed flocs, reagents, coagulation-flocculation, treatment, wastewater.
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Kuryakova, Tatiana A., Sergey G. Bezryadin, Elena Yu Klyukvina, and Larisa V. Mezhueva. "Research of emulsion properties of oil with selection of effective chemical reagents for destruction of arising emulsions." Butlerov Communications 60, no. 12 (December 31, 2019): 110–15. http://dx.doi.org/10.37952/roi-jbc-01/19-60-12-110.
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The presence of aggressive aqueous solutions of mineral salts leads to rapid wear of both oil pumping and refining equipment. Gas separation and preliminary water discharge are difficult. This is one of the reasons that it is necessary to dehydrate the oil emulsion from the moment it was formed, preventing its aging. The second most important reason for oil dehydration in the areas of its production is the high cost of transporting ballast-produced water. To determine the most suitable demulsifier used at the Tsarichansk field, a series of laboratory studies was conducted. According to the results of laboratory tests, it was found that the developed new multifunctional composite demulsifier Denmaster 3010, due to the synergism of the components that make up the composition, shows good dynamics of sediment compared to the base reagents and provides a high degree of emulsion destruction. According to the results of laboratory studies, the most effective in comparison with the basic reagent, both in the dynamics of dehydration and in the residual water content, is the multifunctional composition DenMaster 3010. Reagent DenMaster 3010 is composite demulsifier based on a mixture of organic and aromatic solvents with the addition of nonionic surfactants. Laboratory tests showed that DenMaster 3010 reagent provides a high degree of emulsion destruction at the stages of in-tube demulsification and preliminary discharge. According to the data obtained, when replacing the base reagent with the DenMaster 3010 reagent, at the stages of oil collection, stabilization and a decrease in the average values of water and salt content are observed, i.e. installation work is normalized.
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Rahman, Norbaizurah, and Andri Kusbiantoro. "Investigation on the Degree of Reaction and Strength Performance of Fly Ash Based Geopolymer Binder with Alternative Chemical Reagents." Materials Science Forum 803 (August 2014): 115–19. http://dx.doi.org/10.4028/www.scientific.net/msf.803.115.
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The existence of high calcium contents in fly ash will contribute to the rapid stiffening and low workability of geopolymer paste. This study reports the feasibility of sodium nitrate and citric acid as the alternative admixtures for geopolymer binder. The effects of sodium nitrate and citric acid were independently evaluated at 0.5%, 1.5% and 2.5% of fly ash weight in geopolymer mixture. The effect of these admixtures on fresh geopolymer characteristic was evaluated through series of setting time and flow table workability tests, while degree of hydration, compressive strength and porosity tests were conducted to provide fundamental information on the hardened properties of geopolymer paste. Based on the result of degree of reaction, the inclusion of sodium nitrate in fly ash based geopolymer will increase the level of degree of hydration. Nevertheless, this result is in contrast with citric acid inclusion where degree of hydration decreased along with the increasing dosage of citric acid in the mixture. Strength development of geopolymer paste, particularly during the early age, appears to be affected by various geopolymerization rate presented by these admixtures.
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Suvorin, А. V., M. N. Shorokhov, M. A. Ozheredova, O. N. Bliznjuk, I. M. Ryshchenko, and N. Yu Masalitina. "Purification of Cr(VI)-containing wastewater by chemical precipitation: test results of an experimental-industrial installation." Voprosy Khimii i Khimicheskoi Tekhnologii, no. 3 (May 2021): 121–27. http://dx.doi.org/10.32434/0321-4095-2021-136-3-121-127.
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We present the main results of experimental and industrial study of the developed process and pilot plant for purification of the Cr(VI)-containing rinse water by chemical precipitation. This technique implies full or partial return of treated water to rinse workpieces after chromium plating and prepare working solutions (precipitators). We characterize the manufacturing scheme of the pilot plant and the mode of its performance. Saturated aqueous solutions of Са(ОH)2 and Ва(ОH)2 were used as precipitating reagents. The tests confirmed the possibility of automatic dosing the reagents with due regard for the pH value of a medium, which can be used in both continuous and periodic rinsing. The operating conditions of rinsing the workpieces after electrochemical chromium plating were justified. We derived the equation for the calculation of the total salt content in the rinse water after its purification. We determined the duration of the rinsing without the need to renew the bath volume. The performed calculations substantiated the possibility of reducing the consumption of fresh water supplied for rinsing by the recycling of wastewater without deteriorating the quality of the rinsed workpieces. The reduction of water consumption by 35% was observed as compared with that stated by the regulations.
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Edahbi, Mohamed, Raphaël Mermillod-Blondin, Benoît Plante, and Mostafa Benzaazoua. "CIL Gold Loss Characterization within Oxidized Leach Tails: Creating a Synergistic Approach between Mineralogical Characterization, Diagnostic Leach Tests, and Preg-Robbing Tests." Minerals 9, no. 9 (September 16, 2019): 557. http://dx.doi.org/10.3390/min9090557.
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A double refractory gold ore contains gold particles locked in sulphides, solid-solution in arsenopyrite, and preg-robbing material such as carbonaceous matter, and so on. The diagnostic leach test (DLT) and preg-robbing (PR) approaches are widely used to investigate the occurrence and the distribution of refractory gold. DLT serves to qualitatively evaluate the gold occurrences within the ore. Preg-robbing, or the ore’s capacity to fix dissolved gold, is evaluated to determine physical surface interactions (preg-borrowing) and chemical interactions (preg-robbing). The objective of this project is to characterize the refractory gold in Agnico Eagle Mine’s Kittilä ore using the DLT and PRT approaches coupled with mineralogical analyses to confirm testing. The studied material was sampled from the metallurgical circuit following carbon in leach (CIL) treatment at the outlet of the autoclave in order to investigate the effect of the autoclave treatment on the occurrence and distribution of gold. Different reagents were used in the DLT procedure: sodium carbonate (Na2CO3), sodium hydroxide (NaOH), hydrochloric acid (HCl), and nitric acid (HNO3). The final residue was roasted at a temperature of around 900 °C. These reagents were selected based on the mineralogical composition of the studied samples. After each leaching test/roasting, cyanide leaching with activated carbon was required to recover gold cyanide. The results show that gold is present in two forms (native and/or refractory): to a small extent in its native form and in its refractory form as association with sulfide minerals (i.e., arsenopyrite and pyrite) and autoclave secondary minerals that have been produced during the oxidation and neutralization processes such as iron oxides, iron sulfates, and calcium sulfate (i.e., hematite and jarosite), along with carbonaceous matter. The results of DLT indicate that 25–35% of the gold in the tails is nonrecoverable, as it is locked in silicates, and 20–40% is autoclave products. A regrind can help to mitigate the gold losses by liberating the Au-bearing sulphide minerals encapsulated within silicates.
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Soliz, Álvaro, Luis Cáceres, Fabiola Pineda, and Felipe Galleguillos. "Erosion–Corrosion of AISI 304L Stainless Steel Affected by Industrial Copper Tailings." Metals 10, no. 8 (July 27, 2020): 1005. http://dx.doi.org/10.3390/met10081005.
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A comprehensive analysis of the erosion–corrosion behavior of AISI 304L stainless steel immersed in 0.5 M NaCl solution with the addition of industrial tailing particles obtained from the copper mining industry is reported. From fundamental studies using combined measurements of potentiodynamic and weight loss techniques, the pure corrosion, pure erosion, and their synergism on the total wear rate were evaluated. The results showed that the presence of soluble chemical reagents dragged by tailing particles significantly affects the pure corrosion rate in comparison with a NaCl solution without these chemical reagents. In addition, the wear of stainless steel by pure erosion was found to be more important than that of pure corrosion. Erosion–corrosion tests performed under an open circuit potential behavior indicate lower and higher wear values than that obtained for erosion and corrosion rates, respectively. Through these results, it was possible to determine an antagonistic effect for AISI 304L stainless steel in industrial tailings slurries. These results are supported by changes in the electrochemical parameters, passive film stability, and morphological attributes.
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Sentat, Triswanto, Henny Nurhasnawati, and Yunita Rachma Dwinand. "DEVELOPMENT OF PAPER-BASED COLOR TEST-STRIP FOR PARACETAMOL DETECTION IN JAMU." Jurnal Ilmu Kesehatan 7, no. 2 (January 8, 2020): 137–42. http://dx.doi.org/10.30650/jik.v7i2.1231.
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Chemical medicine which are synthetic chemicals or isolation products must not be added to herbal medicine, that was standared by Indonesian Head of the Drug and Food Control Agency in statement regarding Criteria and Procedure for Registration of Traditional Medicines, Standardized Herbal Medicines, and Phytofarmaka. This study aims to develope prototype of paper-based color test-strip to identify paracetamol trace in several types of Indonesian herbal medicine, better known as Jamu. Research conducted with experimental research wich make paper test-strip prototype by immobilizing reagents into Whatman’s filter paper, then it used to identify paracetamol in extracted Jamu samples. The paracetamol qualitative test uses 10 Jamu samples that distributed in Samarinda area. were also carried out on. Comparison methode with qualitative color reaction tests using specific reagents in the laboratory were also carried out beside the paper-based color test-strip methode. In addition with positive control tests using 5000 ppm paracetamol solution to make sure both methode used are valid. The results of this study showed that two prototype paper-based color test-strips containing 10% iron (III) chloride reagent and folin ciocalteu were able to detect the presence of paracetamol chemicals in Jamu samples with color reaction.
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Wang, Zi Qiang, Li Xian Sun, Fen Xu, and Xiao Jun Peng. "Hydrothermal Synthesis of MnO2-Loaded Porous Carbons for Supercapacitors." Materials Science Forum 852 (April 2016): 870–75. http://dx.doi.org/10.4028/www.scientific.net/msf.852.870.
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The porous carbons have been prepared by chemical activation using commercial activated carbons as precursors and KOH as the chemical agent, and the MnO2 and MnO2-loaded porous carbons have been synthesized via the hydrothermal method using the Mn (SO4)2·H2O and (NH4)2S2O8 as the reagents. The morphology and structure of the obtained materials are characterized by the SEM, XRD and N2 sorption. The obtained MnO2 exhibits rod-like morphology, which can be indexed to a pure tetragonal phase [space group: P42/mnm] of β-MnO2. The porous carbons and MnO2-loaded porous carbons show a well-developed porosity. The electrochemical tests indicate that the samples have excellent performances for the supercapacitors.
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Burnat, B., M. Parchańska-Kowalik, and L. Klimek. "The Influence of Chemical Surface Treatment on the Corrosion Resistance of Titanium Castings Used in Dental Prosthetics." Archives of Foundry Engineering 14, no. 3 (August 8, 2014): 11–16. http://dx.doi.org/10.2478/afe-2014-0052.
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Abstract Air abrasion process is used for cleaning casting surface of prosthetic components, and to prepare the surface of these elements for the application of veneering items. Its side effect, however, is that abrasive particles are embedded in the treated surface, which can be up to 30% of the surface and it constitutes the side effect of this procedure. Such a significant participation of foreign material can not be indifferent to the properties of the surface. Embedded particles can be the place of stress concentration causing cracking of ceramics, and may deteriorate corrosion resistance by forming corrosive microlinks. In the latter cases, it would be advisable to remove elements embedded into the surface. The simplest method is chemical etching or electrochemical one. Nevertheless, these procedures should not significantly change the parameters of the surface. Among many possible reagents only a few fulfills all the above conditions. In addition, processing should not impair corrosion resistance of titanium, which is one of the most important factors determining its use as a prosthetic restoration in the mouth. The study presented results of corrosion resistance of titanium used to make prosthetic components by means of casting method, which were subjected to chemical processing designed to remove the embedded abrasive particles. The aim of the study was to investigate whether etching with selected reagents affects the corrosion resistance of titanium castings. For etching the following reagents were used: 30% HNO3 + 3% HF + H2O, HNO3+ HF+ glycerol (1:2:3), 4% HF in H2O2, 4% HF in H2O, with a control sandblasted sample, not subjected to etching. Tests demonstrated that the etching affected corrosion properties of test samples, in each case the reduction of the corrosion potential occurred - possibly due to the removal of particles of Al2O3 from the surface and activation of the surface. None of the samples underwent pitting corrosion as a result of polarization to 9 V. Values of the polarization resistance, and potentiodynamic characteristics indicated that the best corrosion resistance exhibited the samples after etching in a mixture of 4% solution of HF in H2O2. They showed very good passivation of the surface.
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Surahmaida, Surahmaida, and Umarudin Umarudin. "Toxicity of Miana Leaf (Coleus blumei) Extract Against Houseflies (Musca domestica)." Biosaintifika: Journal of Biology & Biology Education 11, no. 2 (August 17, 2019): 249–55. http://dx.doi.org/10.15294/biosaintifika.v11i2.19402.
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Houseflies (Musca domestica) is an disease-carrying insect that plays an important role in the spread of disease in humans and animals. One way to control houseflies is using Miana leaves (Coleus blumei) as botanical pesticide. The purpose of this study was to determine the chemical compounds contained in Miana leaf as well as determine the optimal concentration of Miana leaf extract in causing knockdown effect in houseflies. Miana leaf fine powder was soaked with methanol (maceration) for 3 days followed byphytochemical screening (chemical reagents and Gas Chromatography Mass Spectrophotometry (GCMS) and anti-houseflies toxicity tests. Testing of methanolic extract of Miana leaves was made in the form of spray using the knockdown method at concentrations of 5%, 10%, 20%, 30% and 40% and observed in 5, 10 and 15 minutes. The results of phytochemical screening with chemical reagents showed that the extract contained alkaloids, tannins, flavonoids, saponins and terpenoids; while the results of GCMS analysis showed 8 bioactive compounds. The results of the study revealed that at a concentration of 30% and 40%, methanolic extract of Miana leaves could result in a knockdown effect that was accompanied by death with a percentage value of 100% in the first 5 minutes of observation. This research shows that methanolic extract of Miana leaves can be used as an alternative to botanical pesticides in controlling houseflies (Musca domestica).
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Milanovic, Dragan, and Zoran Markovic. "Zeta-potential and flotability of the scheelite mineral in different type of waters, Part 2: Flotability." Chemical Industry 63, no. 5 (2009): 377–85. http://dx.doi.org/10.2298/hemind0905377m.
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The aim of this work was to study floatability of the mineral sheelite from mine 'Rudnik', central Serbia. Flotation tests of the mineral in a Hallimond tube cell were carried out in four different types of water, namely: tap water, distilled water, rain water and spring water. All types of water had different hardness and conductivity as well as natural pH values. It was found that the flotability of mineral scheelite depends on the hardness and electro-conductivity of the chosen type of water as well as on Ca2+ content. Also, it was found the floatability of mineral depends on the scheelite particle size fraction used in microflotation experiments. Presented results may be useful for proper selection of type of water, as well of the type of reagents used in flotation processes.
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Bruno, P., G. Acampa, M. G. Giustra, M. De Marchis, C. M. Parisi, and G. Di Bella. "Optimization of management choices of clariflocculation process by means of qualitative multi-criteria analysis." Water Science and Technology 81, no. 5 (March 1, 2020): 1011–28. http://dx.doi.org/10.2166/wst.2020.186.
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Abstract Every year ship traffic produces tons of liquid waste mainly consisting of bilge water and of washing water of tankers' tanks. The latter are called slop waters and are characterized by high salinity and by the presence of recalcitrant pollutants mainly of hydrocarbon origin: these characteristics promote the use of chemical-physical rather than biological treatment. In particular, in the present study the slop waters were subjected to a clariflocculation treatment by means of batch tests. This treatment involves the dosage of specific chemical reagents (coagulants and flocculants) added to water at different stages of the process. In order to establish the optimal reagents' type and dose, also considering the operating costs, the proposed study presents a frequency analysis belonging to the family of multi-criteria exploration. The application of this methodology to examine the validity of the different process alternatives has allowed the inclusion of, in a single assessment, both economic and extra-economic (measurable only in qualitative terms) procedures. Thanks to this qualitative and quantitative method, it was therefore possible to order the different treatment alternatives analyzed, identifying the one that allows optimizing the wastewater management, for a conscious choice of the most suitable solution to the problem.
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Syamsu Nur, Andi Nur Aisyah, Alfat Fadri, Sharfianty, Amriani Sapra, and Fitriyanti Jumaetri Sami. "Comparative study of catechin levels from green tea, oolong tea and black tea product with various treatments." GSC Biological and Pharmaceutical Sciences 14, no. 1 (January 30, 2021): 001–10. http://dx.doi.org/10.30574/gscbps.2021.14.1.0416.
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Background: Tea is a refreshing drink that contains polyphenol compounds, namely catechins that are used for medicine and cosmetics. This study was to assess the content of catechin compounds in green tea, oolong and black tea products from Indonesia, China and Taiwan. Methods: Some tea products are brewed at varying temperatures (75±2; 85±2 and 95±20 C) and times (5; 10 and 15 minutes). Identification of catechin compounds was carried out using chemical reagents and UV spectrophotometry. The level of cathecin in tea products were analyzed by spectrophotometer at 280 nm wavelength. Results: The results obtained indicate that green tea, oolong tea and black tea contain epigallocatechin-3-gallate (EGCG) compounds according to the color change based on chemical reagents and for UV spectrum analysis which has λmax in the range 268-274 nm. The results of quantitative tests using UV-Vis spectrophotometry showed that the green tea samples gave the highest levels of catechins followed by oolong tea and black tea with brewing temperature at 95±20 °C. Conclusion: The catechin content of tea obtained from various products varies according to the type of processing method and the brewing temperature. Therefore, this study is expected to provide information related to catechin content to the public and researchers.
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Nagar S, Mohamed. "Capability of Uranium Heap Leaching From Gattar and El Missikat Area, Eastern Desert, Egypt: A Kinetic Approach." Journal of Engineering and Applied Sciences Technology 2, no. 4 (December 31, 2020): 1–7. http://dx.doi.org/10.47363/jeast/2020(2)115.
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Detailed studies of uranium heap leaching from different uranium mineralization resources situated in Eastern Desert of Egypt were investigated using sulfuric acid via batch experiments, followed by using the obtained optimum condition on bench scale leaching tests using small column. The previous optimum parameters were implemented on another large scale column in order to make more condition control and evaluate the time and reagents needed while transferring from small to large scale. The obtained data shows that leaching efficiency of GII mineralization attained about 78.3% with consumed acid amount about 34 kg/ton in a 44 days as leaching time, on the other hand, leaching efficiency of uranium from El-Missikat mineralization higher than GII mineralization and attained about 86.6% and the consumed as lower than G-II about 28kg/ton in a 40 days leaching time. Kinetics reaction models of column tests have been investigated to optimize the column leaching behavior. Based on the leaching results of the two mineralized occurrences, the rate of the uranium dissolution is controlled by both the chemical reaction and the diffusion reaction but diffusion reaction control was more predominate than a chemical reaction.
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Collivignarelli, Maria Cristina, Giorgio Bertanza, Alessandro Abbà, and Silvestro Damiani. "Process auditing and performance improvement in a mixed wastewater–aqueous waste treatment plant." Water Science and Technology 77, no. 4 (November 30, 2017): 891–98. http://dx.doi.org/10.2166/wst.2017.605.
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Abstract The wastewater treatment process is based on complex chemical, physical and biological mechanisms that are closely interconnected. The efficiency of the system (which depends on compliance with national regulations on wastewater quality) can be achieved through the use of tools such as monitoring, that is the detection of parameters that allow the continuous interpretation of the current situation, and experimental tests, which allow the measurement of real performance (of a sector, a single treatment or equipment) and comparison with the following ones. Experimental tests have a particular relevance in the case of municipal wastewater treatment plants fed with a strong industrial component and especially in the case of plants authorized to treat aqueous waste. In this paper a case study is presented where the application of management tools such as careful monitoring and experimental tests led to the technical and economic optimization of the plant: the main results obtained were the reduction of sludge production (from 4,000 t/year w.w. (wet weight) to about 2,200 t/year w.w.) and operating costs (e.g. from 600,000 €/year down to about 350,000 €/year for reagents), the increase of resource recovery and the improvement of the overall process performance.
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Ji, Deng Gao, Su Qin Peng, Yue Wu, and Yang Hui Cai. "Study of Flotation Effect of ST-1 Complex Reagent." Advanced Materials Research 610-613 (December 2012): 3357–61. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.3357.
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There are lots of problems in coal flotation reagents. For example, it is difficult to disperse in coal pulp, it needs a large consumption, and its selectivity is poor. So this paper refers that kerosene can be made into compound kerosene by using different chemical products and surfactants, and then used for coal flotation. Tests proved that when the ST-1 Complex Reagent dosage is 500g/t, kerosene dosage is 900g/t, clean coal ash consistent is the same, and clean coal yield is closed, collector dosage saved 44.44%, and the fastest floating speed of clean coal is 99.3g/min, 4.8g/min fast than kerosene, Zeta potential is-28.9409mv after kerosene effect, Zeta potential is -13.2555mv after ST-1 Complex Reagent effect.
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Ji, Deng Gao, Yang Hui Cai, Xu Long Guo, Su Qin Peng, and Shuang Guo Wei. "Research of Optimize Performance of Coal Flotation Collectors." Advanced Materials Research 361-363 (October 2011): 296–300. http://dx.doi.org/10.4028/www.scientific.net/amr.361-363.296.
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There are lots of problems in coal flotation reagents. For example, it was difficult to disperse in coal pulp, it needs a large consumption, and its selectivity was poor. So this paper refers that kerosene can be made into compound kerosene by using different chemical products and surfactants, and then used for coal flotation. Tests proved that compound kerosene can disperse in coal pulp quickly; they had a high yield of clean coal, a fast flotation speed and a higher flotation perfection index. As a result, the flotation effect of Fy-6 compound kerosene was the best of all. Clean coal zeta potential of Fy-6 compound kerosene and kerosene had been tested, and they had been compared with raw coal.
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Yang, Na, Qin Liao, Qing Li, Peng Zhang, and Longqin Li. "Simple and easy-operated method for filtering eco-friendly corrosion inhibitors." Anti-Corrosion Methods and Materials 63, no. 2 (March 7, 2016): 73–81. http://dx.doi.org/10.1108/acmm-07-2014-1406.
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Purpose – The purpose of this paper was to find a simple and easy-operated method for filtering eco-friendly corrosion inhibitors. Design/methodology/approach – The molecular structures and atomic electronegativities of the four kinds of natural reagents, iota-Carrageenan, sodium alginate, sodium dodecanesulphonate (SDS) and sodium dodecylbenzene sulfonate were calculated by Gaussian and Natural Bond Orbital, and the corrosion inhibition rates were forecasted by the calculated results. Then, the realistic corrosion inhibition efficiency were confirmed by electrochemical impedance spectroscopy and potentiodynamic polarization tests in 3.5 Wt.% sodium chloride corrosive solutions. At the same time, the function of pefloxacin mesylate (PM) was explored in this paper polarization tests in 3.5 Wt.% sodium chloride corrosive solutions. Findings – Results showed that the order calculated by the chemical software was correct, and the corrosion inhibition of SDS was the best. Optimum addition of PM not only can reduce microbial corrosion but also can improve the corrosion inhibition by spatial cooperation. Practical implications – This method can be used to filter eco-friendly corrosion inhibitors quickly. PM can be also used to improve the corrosion inhibition rate of corrosion inhibitors. Originality/value – The present method to filter corrosion inhibitors was time-consuming, which needed lots of experiments to verify the corrosion inhibitive efficiency. The calculated method was simpler than others, which need complicated calculation process.
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Carliell, C. M., and A. D. Wheatley. "Metal and phosphate speciation during anaerobic digestion of phosphorus rich sludge." Water Science and Technology 36, no. 6-7 (September 1, 1997): 191–200. http://dx.doi.org/10.2166/wst.1997.0591.
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Chemical extraction methods are used to investigate metal and phosphate speciation during anaerobic digestion of phosphorus-rich sludge. Tests were performed using model compounds to evaluate the efficacy of the reagents in the extraction sequences and these results compared with similar work by other researchers. The metal speciation method was found to be suitable for identifying shifts in metal distribution but was unrepresentative of actual metal species. The phosphate speciation method did give adequate separation of the phosphate compounds tested. Full-scale digesters treating chemical and biological phosphate removal (CPR and BPR) sludge were analysed according to the methods developed. Results show that digestion of CPR sludge did not increase the soluble P concentration in the digester and that most of the precipitated phosphorus appeared to be retained in the sludge as inorganic P. The digester treating BPR sludge showed increased soluble and water-extractable P, in comparison to the control digester. Trace metal speciation profiles were found to be affected by addition of CPR sludge.
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Cennamo, Nunzio, Girolamo D’Agostino, Chiara Perri, Francesco Arcadio, Guido Chiaretti, Eva Maria Parisio, Giulio Camarlinghi, et al. "Proof of Concept for a Quick and Highly Sensitive On-Site Detection of SARS-CoV-2 by Plasmonic Optical Fibers and Molecularly Imprinted Polymers." Sensors 21, no. 5 (March 1, 2021): 1681. http://dx.doi.org/10.3390/s21051681.
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The rapid spread of the Coronavirus Disease 2019 (COVID-19) pandemic, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pathogen has generated a huge international public health emergency. Currently the reference diagnostic technique for virus determination is Reverse Transcription Polymerase Chain Reaction (RT-PCR) real time analysis that requires specialized equipment, reagents and facilities and typically 3–4 h to perform. Thus, the realization of simple, low-cost, small-size, rapid and point-of-care diagnostics tests has become a global priority. In response to the current need for quick, highly sensitive and on-site detection of the SARS-CoV-2 virus in several aqueous solutions, a specific molecularly imprinted polymer (MIP) receptor has been designed, realized, and combined with an optical sensor. More specifically, the proof of concept of a SARS-CoV-2 sensor has been demonstrated by exploiting a plasmonic plastic optical fiber sensor coupled with a novel kind of synthetic MIP nano-layer, especially designed for the specific recognition of Subunit 1 of the SARS-CoV-2 Spike protein. First, we have tested the effectiveness of the developed MIP receptor to bind the Subunit 1 of the SARS-CoV-2 spike protein, then the results of preliminary tests on SARS-CoV-2 virions, performed on samples of nasopharyngeal (NP) swabs in universal transport medium (UTM) and physiological solution (0.9% NaCl), were compared with those obtained with RT-PCR. According to these preliminary results, the sensitivity of the proposed optical-chemical sensor proved to be higher than the RT-PCR one. Furthermore, a relatively fast response time (about 10 min) to the virus was obtained without the use of additional reagents.
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Xie, Haiyun, Rui Sun, Jizong Wu, Dongxia Feng, and Likun Gao. "A Case Study of Enhanced Sulfidization Flotation of Lead Oxide Ore: Influence of Depressants." Minerals 10, no. 2 (January 22, 2020): 95. http://dx.doi.org/10.3390/min10020095.
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The refractory lead oxide ore has become an important source of lead metal with the continuous depletion of lead sulfide minerals. Lead oxide ore is of poor floatability and there are few cases to concentrate it successfully. In this study, the sulfidization-xanthate flotation method is applied for the beneficiation of lead oxide ore in Yunnan Province (China) with sodium hexametaphosphate and carboxymethyl cellulose as depressant. Chemical analysis and phase analysis was performed to explore the physicochemical property of raw ore, which provides a research basis for process design and operational control. The main influencing factors during the process, including grinding fineness, reagent types, and dosage, etc., have been studied through flotation tests. Zeta potential measurements and Fourier transfer-infrared spectrometry (FTIR) analysis were conducted to reveal the function mechanism of the reagents. Based on the determined experimental conditions, open circuit tests and closed circuit tests with one stage rougher, three-stage scavenger, and two-stage cleaner flotation, were carried out with the run-of-mine ore with a lead grade of 4.57%. Through close circuit bench test, the lead concentrate with a lead grade of 64.08% and recovery of 92.30% was obtained. This study is of special value, as it provides referencing significance for economically exploiting lead oxide ore.
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Tebogo, Mashifana, and Sithole Thandiwe. "Evaluation of Chemically Treated and Lime Stabilized Gold Mine Tailings: Effect on Unconfined Compressive Strength." Key Engineering Materials 803 (May 2019): 366–70. http://dx.doi.org/10.4028/www.scientific.net/kem.803.366.
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For over 200 years of gold mining, little has been done to minimize the negative impact of gold mine tailings to the environment. The overall generation of tailing by South African gold mining industry is approximately 300 million tons of slimes. This study was conducted to develop an effective chemical treatment process to reduce major heavy metals in the gold mine tailings, to stabilize the treated gold tailings with lime, to enhance its unconfined compressive strength. Two reagents were investigated namely, citric acid and oxalic acid, the concentrations were varied between 0.25 M and 0.5 M. The leaching tests were conducted at temperatures of 25, 50 and 85 °C. The Elemental, mineralogical and micrograph analysis were conducted on the raw gold mine tailing, treated tailings and stabilized tailing. The results showed a higher relative proportion of magnesium, aluminium silicon, iron and sulphate. The relative proportion for all other metals was below 1 wt%. Citric acid proved to be the best chemical reagent and the optimum results were obtained when the leaching tests were conducted at a temperature of 85 °C, with the concentration of 0.5 M. The final treated solid products had major constituents which enhances material strength development, thus silica and aluminium. Stabilising the treated tailings with 30% hydrated lime, improved the unconfined compressive strength from 1.14 MPa to 2.9 MPa.
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Wacheux, H., J. L. Million, C. Guillo, and E. Alves. "NH4 automatic analysers for wastewater treatment plant: evaluation test at laboratory and field level." Water Science and Technology 33, no. 1 (January 1, 1996): 193–201. http://dx.doi.org/10.2166/wst.1996.0019.
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Nine NH4 automatic analysers or monitors were tested in June-July 1995 (among them 2 prototypes): - 5 based on ion electrode; ABB, Applikon, Contronic, Hydro-Environnement, STIP, - 4 based on colorimetry; Danfoss, Data Link (UV absorption), Meerestechnik, Skalar Laboratory tests are aimed to determine response time, repeatability, response linearity, short-term stability, influence of various factors on the measurement. The field test relates to real conditions: all the sensors were installed in parallel at the discharge point of a Wastewater treatment plant (WWTP). Recorded outputs were compared with conventional laboratory analysis of average hourly samples. Response time range from 2 to 21 minutes. Repeatability varies from 1 to 10%, stability from 1 to 17%. Linearity is always good and detection limits (about 0.2 mg/l) do not seem to be critical for use in a WWTP. Among factors of influence, power voltage has limited effect, sample temperature is affecting some monitors, chemical interferents have nearly no effect excepted for one monitor. Field tests have shown that NH4 monitors are still very sensitive and that installation is crucial. Each monitor suffered several failures, some of them required high maintenance and used costly reagents.
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Rangel, Ricardo, Verónica Cedeño, Jaime Espino, Pascual Bartolo-Pérez, Geonel Rodríguez-Gattorno, and Juan Alvarado-Gil. "Comparing the Efficiency of N-Doped TiO2 and N-Doped Bi2MoO6 Photo Catalysts for MB and Lignin Photodegradation." Catalysts 8, no. 12 (December 19, 2018): 668. http://dx.doi.org/10.3390/catal8120668.
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In this study, we tested the efficiency of nitrogen-doped titanium dioxide (N-TiO2) and nitrogen-doped bismuth molybdate (N-Bi2MoO6) compounds as photocatalysts capable of degrading methylene blue and lignin molecules under irradiation with ultraviolet (UV) and visible light (VIS). Moreover, we compared TiO2 and Bi2MoO6 catalysts with N-TiO2 and N-Bi2MoO6 compounds using chemical coprecipitation. The catalysts were prepared starting from Ti(OCH2CH2CH3)4, Bi(NO3)3·5H2O, and (NH4)6Mo7O24 reagents. N-doping was achieved in a continuous reflux system, using ethylene diamine as a nitrogen source. The resulting materials were characterized using Scanning Electron Microscopy (SEM), X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Additionally, we observed the decrease in particle size after processing the compounds in the reflux system. The results regarding photocatalytic degradation tests show a remarkable effect for nitrogen doped samples, achieving 90% of lignin degradation.
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da Silva Oliveira, José Carlos, R. A. Sanguinetti Ferreira, and Yogendra Prasad Yadava. "Sintering of Ca2MgWO6 Ceramic and its Stability Test in Crude Petroleum." Materials Science Forum 820 (June 2015): 149–54. http://dx.doi.org/10.4028/www.scientific.net/msf.820.149.
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The main objectives of this work were the production of Ca2MgWO6ceramic by sintering and the investigation of its reactivity to crude petroleum. A synthesis was prepared with stoichiometric amounts of CaO, MgO and WO3. The reagents were characterized according to chemical composition. The synthesis was characterized by size distribution and thermal analysis. A green compact of the synthesis was calcined at 1200 °C and analyzed by XRD. The result showed that the calcined material consists predominantly of a complex perovskite-type Ca2MgWO6ceramic. The calcined material was fragmented in a ball mill and used to prepare three green compacted to be sintered at temperatures of 1250, 1300 and 1350 °C. The sintered material was evaluated by linear shrinkage, microhardness, SEM, microanalysis by dispersive energy and stability tests in crude petroleum. The results showed that it is possible to produce a material with 74.5 % of Ca2MgWO6and that is inert to crude petroleum.
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Jaturas, Narong, Tooba Mahboob, Nadiah Azman, Tan Tian-Chye, and Veeranoot Nissapatorn. "Malaria in Children: Diagnostic Tools in Resource-Limited Settings." Journal of Pediatric Infectious Diseases 12, no. 04 (June 8, 2017): 249–55. http://dx.doi.org/10.1055/s-0037-1603587.
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AbstractMalaria contributes to a major reason for the cause of fatality and serious health problems among children mainly in various parts of tropical Africa and Asia. The extraction of DNA plays a vital role in the diagnosis of this life-threatening parasite Plasmodium. Difficulties with existing extraction methods of DNA are increasing with time including detection limits, time duration, sensitivity, availability of chemicals, and cost. Consequently, there is now renewed interest in finding of novel methods for DNA extraction of Plasmodium. However, the extraction of DNA by using microwave irradiation is found to be most convenient and suitable due to its low-cost and usage of common chemical reagents especially for the children in poor resource settings. In addition, the low cost, noninvasive malaria diagnostics tests are needed to carry out particularly for children to avoid accidental infections which may happen due to drawing blood.
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Frýbort, Aleš, Jana Štulířová, and Jiří Grošek. "Complementary analyses of concrete characteristics performed on cores taken from concrete pavements." MATEC Web of Conferences 310 (2020): 00036. http://dx.doi.org/10.1051/matecconf/202031000036.
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The basic assessment of cement concrete pavement condition is performed by a visual inspection, when the surface faults which are macroscopically distinguishable are documented. Detailed data on concrete condition require further tests performed on cores. Apart from common standard tests, such as layer thickness, compressive and tensile strength, resistance against water and chemical defrosting agents, other macroscopic and microscopic analyses have become useful. Some of the most important ones include petrographic assessment of aggregates (based on the fraction and type of rocks), quantification of cracks (expressed by e.g. cracking index or damage rating index), analyses of air void characteristics in concrete (expressed by e.g. spacing factor test), indication of type and extent of expansion reactions with the help of chemical reagents that visually mark the affected concrete parts. The information can be complemented and adjusted through a suitable combination of microscopic methods. Prepared thin sections are used to determine types of aggregates including the specification of its harmfulness. In combination with concrete fragments taken at least from three height levels of the core (surface-centre-bottom), differences or conformity of concrete porousness, and level and type of mineralization of pores and cracks created by secondary phases, are determined. The identification of created phases and their correlation with applied aggregates can be used for prediction of potential risks. The paper describes additional test methods that can be performed on cores from concrete structures and that are based on macroscopic and microscopic analyses.
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Vanbroekhoven, Karolien, Sandra Van Roy, Ludo Diels, Johan Gemoets, Paul Verkaeren, Ludo Zeuwts, Karel Feyaerts, and Francis van den Broeck. "Sustainable Approach for the Immobilization of Metals in the Saturated Zone: In Situ Bioprecipitation." Advanced Materials Research 20-21 (July 2007): 261–66. http://dx.doi.org/10.4028/www.scientific.net/amr.20-21.261.
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In order to remediate three sites in the vicinity of a non-ferrous industrial site, where groundwater was historically contaminated with metals, the best available technique should be selected. Because the groundwater contained high concentrations of metals and high sulphate concentrations (up to 2000 ppm), the feasibility of sulphate reduction and subsequent metal immobilization due to metal sulphide precipitation was examined in the lab before selecting an appropriate remediation technology. Because of the very high metal concentrations in the groundwater and their potential toxic effects on microbial life chemical reagents were also evaluated for immobilization of the metals in situ. The first site (site 1) was characterized by a contamination of Zn (500ppm-3ppm) up to a depth of 130 m-bg. A screening for inducibility of biological activity was performed at two depths – 30 m-bg (below ground) and 65 m-bg -- using microcosm experiments containing both aquifer solids and groundwater. Different electron-donors were selected including pure chemical agents such as lactate and waste products such as molasses and glycerol. Glycerol resulted in the most efficient metal and sulphate removal after about 106 days. Extremely high Zn concentrations were found in the groundwater of the second site (site 2), i.e., up to about 2000 ppm. Similar lab tests applied for site 1 were performed, but in addition chemical agents (NaS2 and CaSx) were used. Whereas the sulphide containing chemical agents immediately resulted in low Zn concentrations in the groundwater, it took >140 days before biological sulphate removal started. Glycerol, lactate and molasses resulted in efficient Zn removal. Site 3 was characterized by relative shallow contamination (<10 m-bg) of mainly Co (30-300 ppm), and containing typical sulphate concentrations in the range of 300-1200 ppm. Rapid microbial sulphate reduction (within 50 days) was induced in the tests containing nutrient-amended lactate, cheese whey and soy oil.
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Golovko, A. K., V. F. Kamyanov, and T. A. Filimonova. "The Novelties Producing by Ozonolysis of Petroleum High-Molecular Components." Eurasian Chemico-Technological Journal 7, no. 2 (July 13, 2017): 89. http://dx.doi.org/10.18321/ectj620.
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Specific properties of ozonolysis products of high-molecular heteroatomic compounds (resins and asphaltenes) from crude petroleums and natural bitumens are described. It is shown that polyfunctional carboxylic acids or their salts obtaining by alkaline hydrolysis of ozonization products of heavy petroleum<br />stocks permits to produce manifold useful novelties such as high-effective demulsifiers for petroleum dehydration process instead of expensive synthetic demulsifying reagents; water-soluble organic astringents suitable for chemical land-reclamation or to prepare moulding mixtures at the foundries; oily or emulsion<br />lubricating coolants for metal-working tools; stimulators of soil microorganisms activity and plant growth. The new chemical products of petroleum origin are not inferior to the best synthetic reagents for the same destinations but differ from the lasts advantageously on account of the simplicity of their production technology and low cost. The optimal expenses and other principal technological parameters were established both for raw material ozonization, following alkaline treatment and final product isolation stages of the production process for each new reagent described. By means of numerous laboratory experiments and field tests performed with seeds, bulbs and grafts of different agricultural plants and with ozonolysis products produced from the resinous components of different crude petroleums it was proved that high biological activity is characteristic only of the substances obtained from high-molecular compounds from low-sulfur naphthenic crude petroleums and natural bitumens occurring, as a rule, at small burial depths. These ozonolysis products are very effective stimulants for the different plants growth, suitable for a treatment of different forms of planting materials and providing significant acceleration of early growth stages, the reduction of vegetation and ripening periods, and the increase of total productivity of agricultural plants.
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Albrektienė, Ramunė, Mindaugas Rimeika, Elena Zalieckienė, Valentinas Šaulys, and Alvydas Zagorskis. "DETERMINATION OF ORGANIC MATTER BY UV ABSORPTION IN THE GROUND WATER / ORGANINIŲ MEDŽIAGŲ POŽEMINIAME VANDENYJE NUSTATYMAS TAIKANT UV BANGŲ ABSORBCIJĄ." Journal of Environmental Engineering and Landscape Management 20, no. 2 (June 7, 2012): 163–67. http://dx.doi.org/10.3846/16486897.2012.674039.
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Organic matter in drinking water is determined by applying indirect determination methods used for quantitative measurements such as total organic carbon (TOC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD). These analyses require expensive devices, harmful chemical reagents, and are time consuming. Standard water quality tests are inconvenient during start-up or reconstruction of drinking water treatment plants as samples need to be transported to a laboratory and no on-line measurements on plant performing efficiency are available. For practical purposes, less sophisticated and faster methods to determine organic matter are required. One of the methods could be ultraviolet absorption of water at 254 nm wavelength (UV254). It is a technically simple and fast method for determining natural organic matter, requiring neither expensive measurement equipment nor chemical reagents. The present article aims at investigating the possibilities of practical applications of UV254 method to determine the concentration of natural organic matter in ground water. The research proved good correlation between TOC and UV254, as well as between CODMn and UV254. The outcomes of the research indicate that UV254method can be successfully applied to determine natural organic matter concentrations in ground water. Santrauka Organinės medžiagos požeminiame vandenyje nustatomos netiesioginiais kiekybiniais bendrosios organinės anglies (BOA), cheminio deguonies suvartojimo (ChDSMn) ir biocheminio deguonies suvartojimo (BDS) metodais. Šioms analitėms nustatyti būtini brangūs prietaisai, kenksmingi cheminiai reagentai, tyrimai ilgai trunka. Diegiant naujus geriamojo vandens gerinimo įrenginius ir atliekant įrenginių paleidimo, derinimo bei eksploatavimo proceso efektyvumo vertinimą, minėtuosius geriamojo vandens tyrimus nepatogu ir brangu atlikti, todėl šiais atvejais reikia paprastesnio ir greitesnio organinių medžiagų nustatymo metodo. 254 nm bangos ilgio (UV254) ultravioletinių spindulių absorbcija yra techniškai paprastas, spartus organinių junginių koncentracijų nustatymo metodas, jį taikant nebūtina brangi tyrimų įranga bei cheminiai reagentai. Šio darbo tikslas buvo ištirti UV254 metodo tinkamumą organinių junginių koncentracijoms nustatyti požeminiame vandenyje. Atlikus tyrimus apibrėžtos priklausomybės tarp BOA ir UV254 bei tarp ChDSMn ir UV254. Remiantis tyrimų rezultatais galima teigti, kad ultravioletinių spindulių absorbcijos metodas gali būti sėkmingai taikomas organinių junginių koncentracijoms požeminiame vandenyje nustatyti.
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Kamel, Nariman H. M. "The Behaviour of134Cs,60Co, and85Sr Radionuclides in Marine Environmental Sediment." Scientific World JOURNAL 2 (2002): 1514–26. http://dx.doi.org/10.1100/tsw.2002.290.
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This work describes experimental investigations and modelling studies on the sorption of radionuclides134Cs,60Co, and85Sr by certain marine sediments within Egypt. The chemical composition of the marine sediments was determined. The soluble salts were measured for the sediments and the concentrations of the released cations, Al3+, Fe3+, and Si4+, were measured for the sediment materials in 0.1 M NaClO4aqueous solution at different hydrogen ion concentrations. The two main factors that control the uptake of the radionuclides onto the sediment are the pH and the exchangeable capacities of the sediment materials. Surface complex model was used to estimate the surface charge densities and the electric surface potential of the marine sediment materials. These two parameters were calculated at the surface capacity sites of the sediment materials. The desorption of the adsorbed cations was determined by means of selective consecutive extraction tests using different chemical reagents including (1) 1 M MgCl2(pH 7), (2) 1 M ammonium oxalate (pH 3-5), (3) 0.04 M NH2OH,HCl in 25% acetic acid (pH 3-4), (4) H2O2in 5% HNO3(pH 2-3), and (5) digestion with nitric acid followed by hydrofluoric and perchloric acids (pH 2).
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Lagos-Sandoval, José Arturo, Jorge Eduardo Salazar-Zuñiga, and Edwing Oswaldo Berdugo-Romero. "Design and simulation of microfluidic device for the detection of HIV." Visión electrónica 1, no. 2 (August 13, 2018): 192–97. http://dx.doi.org/10.14483/22484728.18376.
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This article presents a diagnostic device model, which by using chemical reagents and microfluidics that makes a sort of particle separation and was developed to diagnose an acquired viral immunodeficiency. The device allows to isolate leukocytes and apply a reagent that measures the presence or absence of this virus. The design on the other hand uses tools such as SolidWorks and Autodesk Simulation, which, with the rupture of the membranes and the separation of their components, allows the chemical reaction in the particles and the detection of the virus.
Based on the choice of particle analysis and validating the performance of the fluid maintained in the filter stage, which is represented by 5 flow lines, it shows the movement of 5 particles with the same diameter. Additionally, three tests were performed that varied the diameter of the particles to 5 μm, 10 μm and a larger diameter particle (15 μm). The results show that, with a diameter of 5 μm, the particles move smoothly and the filter can reach the next stage. The particles of 10 μm in diameter presented a normal blood flow, however, an obstruction in the particles of 15 μm in diameter can be observed.
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Skorupska, Malgorzata, Piotr Kamedulski, Jerzy P. Lukaszewicz, and Anna Ilnicka. "The Improvement of Energy Storage Performance by Sucrose-Derived Carbon Foams via Incorporating Nitrogen Atoms." Nanomaterials 11, no. 3 (March 17, 2021): 760. http://dx.doi.org/10.3390/nano11030760.
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This paper addresses the problem of improving electrochemical energy storage with electrode materials obtained from common raw ingredients in a facile synthesis. In this study, we present a simple, one-pot route of synthesizing microporous carbon via a very fast reaction of sucrose and graphene (carbon source), chitosan (carbon and nitrogen source), and H3PO4. Porous carbons were successfully produced during high temperature carbonization, using nitrogen as a shielding gas. Samples were characterized using X-ray powder diffractometry, elemental analysis, N2 adsorption-desorption measurements, scanning electron microscopy, and Raman spectroscopy. The developed carbon material possessed a high surface area, up to 1313 m2 g−1, with no chemical or physical activators used in the process. The structural parameters of the microporous carbons varied depending on the ratio of reagents and mass composition. Samples were prepared both with and without chitosan. The present synthesis route has the advantages of being a single-step approach and only involving low-cost and environmentally friendly sources of carbon. More importantly, microporous carbon was prepared without any activators and potentially offers great application in supercapacitors. Cyclic voltammetry and constant current charge–discharge tests show that sucrose-based porous carbons show excellent electrochemical performance with a specific capacitance of up to 143 F g−1 at a current density of 1 A g−1 in a 6 M KOH electrolyte.
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Dewi, Melisa Pramesti, Himawan Tri Bayu Murti Petrus, and Naoko Okibe. "Recovering Secondary REE Value from Spent Oil Refinery Catalysts Using Biogenic Organic Acids." Catalysts 10, no. 9 (September 20, 2020): 1090. http://dx.doi.org/10.3390/catal10091090.
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Spent catalysts produced by oil refinery industries are regarded as an important secondary source for valuable metals. In particular, spent fluid catalytic cracking (FCC) catalysts represent a potential source for rare earth elements (REEs). This study aimed to exploit the leachability of spent FCC catalysts as a secondary source for La, by using an alternative organic acid lixiviant produced under optimized fungal fermentation conditions. The first chemical leaching tests revealed that citric acid (>100 mM) is a comparable alternative lixiviant to conventional inorganic acids (1 M) and that the La dissolution behavior changed significantly with different types of organic acids. The initial fungal fermentation conditions (e.g., inoculum level, substrate concentration, pH) largely affected the resultant biogenic acid composition, and its manipulation was possible in order to almost solely ferment citric acid (~130 mM) while controlling the production of unwanted oxalic acid. The performance of actual biogenic acids (direct use of cell-free spent media) and artificially reconstituted biogenic acids (a mixture of chemical reagents) was nearly identical, achieving a final La dissolution of ~74% at a pulp density of 5%. Overall, the microbiological fermentation of organic acids could become a promising approach to supply an efficient and environmentally benign alternative lixiviant for REE scavenging from spent FCC catalyst wastes.
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Reiza, Inul Ahmanda, Laode Rijai, and Febrina Mahmudah. "Skrining Fitokimia Ekstrak Etanol Kulit Nanas (Ananas comosus (L.) Merr)." Proceeding of Mulawarman Pharmaceuticals Conferences 10 (October 31, 2019): 104–8. http://dx.doi.org/10.25026/mpc.v10i1.371.
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Pineapple (Ananas comosus (L.) Merr) is one type of fruit that is in demand by the community, both local and world. Pineapple has a waste part that is skin. Pineapple skin in Indonesia is generally just thrown away as waste, whereas pineapple skin contains chemical compounds that are known to have properties. The purpose of this study was to determine secondary metabolite compounds found in pineapple skin. This type of research is descriptive qualitative. Then the method used is phytochemical analysis. The Positive test of this method is characterized by a change in color. Pineapple skin samples were taken from Samarinda, East Kalimantan. The extract was carried out by maceration of dry samples using 96% ethanol solvent. The results of the pineapple skin extraction are then carried out phytochemical screening tests using certain reagents. Phytochemical screening tested included flavonoids, alkaloids, steroids, triterpenoids, tannins, phenolics, and saponins. Based on the results of phytochemical screening research, positive pineapple skin extracts contain flavonoids, alkaloids, tannins, and saponins, while negative results contain phenolic compounds, steroids, and triterpenoids.
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Kuzin, Evgenii N., and Nataliya E. Krutchinina. "EVALUATION OF EFFECTIVENESS OF USE OF COMPLEX COAGULANTS FOR WASTEWATER TREATMENT PROCESSES OF MECHANICAL ENGINEERING." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 10 (October 29, 2019): 140–46. http://dx.doi.org/10.6060/ivkkt.20196210.5939.
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In the course of the work, the quantitative and qualitative characteristics of the wastewater of the machine-building enterprises of the Moscow and Penza regions were investigated. It was found that in most cases the most difficult to remove contaminants are oil products entering the wastewater from metal processing operations, as well as heavy metal ions. Due to the lack of separation of stormwater, industrial and domestic sewage systems, the effluent under study had high concentrations of dissolved organic compounds (Biological Oxygen Demand BOD/chemical oxygen demand COD) and suspended solids. Laboratory tests of experimental samples of complex coagulant on waste water of real production were carried out. Normal aluminum sulfate and aluminum sulfate modified with hydrolysis products of titanium tetrachloride (complex coagulant) were used as reagents. It has been established that complex titanium-containing reagents are effective in the processes of coagulation sewage treatment of machine-building enterprises. The process of flocculation and sedimentation proceeded at a high rate due to flocculation reactions on the surface of titanium hydroxo-complexes, as well as nucleation phenomena on the surface of titanium hydroxide particles. The increased efficiency of samples modified by hydrolysis products of titanium coagulant compounds with respect to traditional aluminum sulfate has been proved. The consumption of complex coagulant compared with aluminum sulfate was about 1.25 - 1.5 times lower, while its efficiency is about 5 - 10% higher. The increased efficiency of complex coagulants with respect to the indicators of oil products, COD and color (organic pollutants) was noted, which is due to the developed adsorption surface of titanium hydroxide flakes in comparison with aluminum hydroxide.
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Guo, Xiaoyan, Jiaqi Liu, Lixia Liu, Suohe Yang, Guangxiang He, and Haibo Jin. "Preparation, Characteristics, and Application of Bifunctional TiO2 Sheets." Materials 13, no. 7 (April 1, 2020): 1615. http://dx.doi.org/10.3390/ma13071615.
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TiO2 is a high-reflectance material for preparing sheets during dry reagent chemical tests in detail. In this study, bifunctional TiO2 sheets with diffusive and reflective properties were prepared using TiO2 microspheres (particle size 2–3 µm) and cellulose acetate (CA). Factors such as the CA dosage, water content, mixing time, and the choice of surfactant were investigated. The structure and properties of the bifunctional TiO2 sheets were characterized by thermogravimetry and differential thermal analysis (TG-DAT), scanning electron microscopy (SEM), dynamic contact angle test and reflectance spectroscopy. By studying the above experimental results, it was concluded that the most optimal preparation conditions for preparing the bi-functional TiO2 sheets under natural drying conditions were as follows: the mass ratio of CA to TiO2 microspheres was 0.05:1; Triton-100 was used to improve the diffusion performance of the bifunctional sheets, after mixing for 5 h and coating. The light reflectivity of the bifunctional TiO2 sheets in the 420 to 800 nm range was higher than 90%. Serum diffused in the bifunctional TiO2 sheets reacted in the reagent sheets and formed uniform colorful spots. Considering the repeatability of spot proportion and light reflectivity, the sheet offered a uniform serum diffusion and good repeatability. So, the bifunctional TiO2 sheets are nominated as a promising material for dry chemical diagnostic reagents.
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Rahman, MD Abdur, M. Shamim Hossain, Nabil A. Alrajeh, and B. B. Gupta. "A Multimodal, Multimedia Point-of-Care Deep Learning Framework for COVID-19 Diagnosis." ACM Transactions on Multimedia Computing, Communications, and Applications 17, no. 1s (March 31, 2021): 1–24. http://dx.doi.org/10.1145/3421725.
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In this article, we share our experiences in designing and developing a suite of deep neural network–(DNN) based COVID-19 case detection and recognition framework. Existing pathological tests such as RT-PCR-based pathogen RNA detection from nasal swabbing seem to display low detection rates during the early stages of virus contraction. Moreover, the reliance on a few overburdened laboratories based around an epicenter capable of supplying large numbers of RT-PCR tests makes this testing method non-scalable when the rate of infections is high. Similarly, finding an effective drug or vaccine with which to combat COVID-19 requires a long time and many clinical trials. The development of pathological COVID-19 tests is hindered by shortages in the supply chain of chemical reagents necessary for testing on a large scale. This diminishes the speed of diagnosis and the ability to filter out COVID-19 positive patients from uninfected patients on a national level. Existing research has shown that DNN has been successful in identifying COVID-19 from radiological media such as CT scans and X-ray images, audio media such as cough sounds, optical coherence tomography to identify conjunctivitis and pink eye symptoms on the ocular surface, body temperature measurement using smartphone fingerprint sensors or thermal cameras, the use of live facial detection to identify safe social distancing practices from camera images, and face mask detection from camera images. We also investigate the utility of federated learning in diagnosis cases where private data can be trained via edge learning. These point-of-care modalities can be integrated with DNN-based RT-PCR laboratory test results to assimilate multiple modalities of COVID-19 detection and thereby provide more dimensions of diagnosis. Finally, we will present our initial test results, which are encouraging.
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Paiva, Weslley de Souza, Francisco Ernesto de Souza Neto, Erika de Souza Paiva, and Anabelle Camarotti de Lima Batista. "Fungal chitosan as membranous material modified by atmospheric plasma." Research, Society and Development 10, no. 1 (January 4, 2021): e9210111543. http://dx.doi.org/10.33448/rsd-v10i1.11543.
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Objective: This study produced a fungal chitosan membrane extracted from Rhizopus stolonifer, as well as its modification using dielectric barrier discharge plasma (DBD), aiming to improve the physicochemical characteristics of the membrane, optimizing its use in the medical research field. Method: The obtained chitosan was physically and chemically characterized (Molecular Weight, Fourier Transform Infrared, X-ray Diffraction), later were produced fungal chitosan membranes and DBD plasma was applied. The membranes were characterized before and after plasma application using the tests contact angle, swelling and atomic force microscopy (medium roughness) analyzes. Results: A fungal chitosan with a yield of 16.73 mg/g, and an apparent molecular weight of 4 kDa was obtained, being considered of low molecular weight and high degree of deacetylation (84%). It was possible to obtain the membrane and after application of DBD plasma, the contact angle dropped from 77.5° to 30.9°, making it more hydrophilic. Conclusion: Thus, the efficiency of the technique for increasing the hydrophilicity of the fungal chitosan membrane without the additive of chemical reagents during the process was confirmed and the membrane formed is a promising alternative can be used in different ways in the medical area.
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Schembri, C. T., V. Ostoich, P. J. Lingane, T. L. Burd, and S. N. Buhl. "Portable Simultaneous Multiple Analyte Whole-Blood Analyzer for Point-of-Care Testing." Clinical Chemistry 38, no. 9 (September 1, 1992): 1665–70. http://dx.doi.org/10.1093/clinchem/38.9.1665.
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Abstract We describe a portable clinical chemistry analyzer for point-of-care measurements of multiple analytes in less than 10 min from approximately 40 microL of whole blood (fingerstick or venous). Whole blood is applied directly to a 7.9-cm-diameter, single-use plastic rotor containing liquid diluent and greater than or equal to 4-12 tests in the form of 1- to 2-mm-diameter dry reagent beads. The reagent/rotor is immediately placed in a portable instrument along with a ticket/label results card. As the instrument spins the rotor, capillary and rotational forces process the blood into diluted plasma, distribute the patient's diluted sample to cuvettes containing the reagent beads, and mix the diluted sample with the reagents. The instrument monitors the chemical reactions optically at nine wavelengths; sample volume and temperature are also measured optically. The calibration data for each reagent are read from a bar code on the periphery of each rotor. The instrument processes all the measurements to calculate, store, print, and communicate the results. Each reagent/rotor contains an enzymatic control that must be within a defined range before the results from that analysis are reported.
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Bhatti, Muhammad Arif, Kamran Raza Kazmi, Abdul Ahad, Anila Tabassum, Rashid Mehmood, and Adnan Akram. "Beneficiation Studies on Low-Grade Complex Polymetallic Lead-Zinc Ore of Duddar (Lasbela) Balochistan, Pakistan." Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences 59, no. 3 (October 27, 2016): 130–43. http://dx.doi.org/10.52763/pjsir.phys.sci.59.3.2016.130.143.
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A bench-scale beneficiation study was performed on low-grade complex lead-zinc ore of Duddar area, District Lasbela, Balochistan Province, Pakistan. The polymetallic ore under investigation contains galena and sphalerite as valuable minerals of lead and zinc. The low-grade ore was upgraded by selective sequential froth flotation technology to recover both minerals. An effort was made to investigate the effect of important variables on grade and recovery of concentrates and to design the process flow sheet. Different parameters of flotation process such as particle size of the feed, pH and % solids of the pulp, speed of impeller, type of reagents (collectors, frothers, regulators and modifiers) and their quantities, conditioning time and flotation time were optimized to attain maximum grade and recovery of respective concentrates. The rougher concentrates obtained were subjected to one regrinding and two cleaning operations to achieve higher-grade concentrates of both metals. Bench-scale flotation tests show that it is possible to obtain a lead concentrate assaying 65.24% Pb with recovery rate of 81.32% and a zinc concentrate containing 55.63% Zn content with recovery rate of 80.28%. Both the concentrates meet the specifications required for metallurgical and chemical grades.