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G., Mohan Muralikrishna, Mayur Vaidya, B. S. Murty, Sergiy V. Divinski i Gerhard Wilde. "Tracer diffusion in ordered pseudo-binary multicomponent aluminides". Scripta Materialia 178 (marzec 2020): 227–31. http://dx.doi.org/10.1016/j.scriptamat.2019.11.044.
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Kwon, K. C., T. H. Ibrahim, YoonKook Park i C. M. Simmons. "Pseudo-binary molecular diffusion of vapors into air". Advances in Environmental Research 8, nr 3-4 (marzec 2004): 667–78. http://dx.doi.org/10.1016/s1093-0191(03)00039-x.
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Santra, Sangeeta, i Aloke Paul. "Estimation of intrinsic diffusion coefficients in a pseudo-binary diffusion couple". Scripta Materialia 103 (lipiec 2015): 18–21. http://dx.doi.org/10.1016/j.scriptamat.2015.02.027.
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Fukaya, Haruhiko, Md Moniruzzaman, Yoshinori Murata, Masahiko Morinaga, Toshiyuki Koyama, Wataro Hashimoto, Katsushi Tanaka i Haruyuki Inui. "Diffusion of Ti, V and Nb in Ni3Al at Elevated Temperatures". Defect and Diffusion Forum 297-301 (kwiecień 2010): 384–89. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.384.
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Interdiffusion coefficients of Al replacing elements in Ni-Al-X (X=Ti, V and Nb) were estimated by a series of experiments using diffusion couples of Al rich pseudo-binary systems at three different temperatures of 1423, 1473 and 1523K. In order to obtain interdiffusion coefficients of the pseudo-binary systems, the experimental data was analyzed by the Sauer and Freise method, and also impurity diffusion coefficients of Ti, V and Nb in Ni3Al were estimated by applying the Darken-Manning equation. The magnitude of interdiffusion coefficient decreased in order of V, Ti and Nb at all three temperatures. Impurity diffusion coefficients were described by the expressions: , , . The activation enthalpies obtained from the experimental data confirmed the retardation of Ti, V and Nb diffusion in Ni3Al by the anti-site diffusion mechanism. These results are consistent with our previous work on diffusion of Re and Ru in Ni3Al .
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G. M., Vishwas C., R. Sanjeev Kunte i Varun Yarehalli Chandrappa. "Encryption Using Binary Key Sequences in Chaotic Cryptosystem". International Journal of Computer Network and Information Security 15, nr 4 (8.08.2023): 48–60. http://dx.doi.org/10.5815/ijcnis.2023.04.05.
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Transmission of images on the network is considered insecure which has security-related issues. In this paper, to provide security to digital images, an encryption system that uses four chaotic maps for binary key sequence generation is proposed. The system consists of stages namely, confusion, generation of random binary chaotic key sequence, pseudo-random number generation (RN), and diffusion. Keys for encryption are chosen randomly based on a pseudo random generator from the selected chaotic maps by the linear feedback shift register (LFSR). The algorithm achieves good results in terms of NPCR, UACI, and entropy values. The developed cryptosystem resists differential attacks, is sensitive to minor alterations in the keys, and has a large key space.
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Esakkiraja, Neelamegan, Keerti Pandey, Anuj Dash i Aloke Paul. "Pseudo-binary and pseudo-ternary diffusion couple methods for estimation of the diffusion coefficients in multicomponent systems and high entropy alloys". Philosophical Magazine 99, nr 18 (25.05.2019): 2236–64. http://dx.doi.org/10.1080/14786435.2019.1619027.
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Yeddou Mezenner, N., A. Hamadi, S. Kaddour, Z. Bensaadi i A. Bensmaili. "Biosorption Behavior of Basic Red 46 and Violet 3 by DeadPleurotus mutilusfrom Single- and Multicomponent Systems". Journal of Chemistry 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/965041.
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The performance of nonviableP. mutilusfor removal of Crystal Violet (CV) and Basic Red 46 (BR46) was investigated in single and binary systems. Batch kinetic studies were carried out as a function of pH, temperature, biomass amount, and dye concentration to determine the decolorization efficiency of biosorbent. In single system, the biosorption capacities ofP. M.reached 166 and 76.92 mg/g for CV and BR46, respectively. A comparison of kinetic models applied to the adsorption of basic dyes ontoP. Mutiluswas evaluated for the pseudo-second-order and intraparticle diffusion kinetics models. The experimental data fitted very well the pseudo-second-order kinetic model, whereas diffusion is not only the rate-controlling step. The thermodynamic study indicates that the adsorption of dyes is spontaneous and endothermic process. In binary system, the biosorption capacities ofP. Mutilusfor both dyes decreased significantly compared to that in single system. Competitive coefficients calculated on a concentration basis using Sheindorf-Rebhun-Sheintuch (SRS) equation were useful for describing the degree of competitive interaction inP. M.
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Leaist, Derek G., i Robert A. Noulty. "An eigenvalue method for determination of multicomponent diffusion coefficients. Application to NaOH + NaCl + H2O mixtures". Canadian Journal of Chemistry 63, nr 2 (1.02.1985): 476–82. http://dx.doi.org/10.1139/v85-077.
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A general method for the determination of multicomponent diffusion coefficients is developed using the algebraic technique of matrix diagonalization. When linear combinations of measurements from several multicomponent diffusion experiments performed with different initial concentration gradients (but with the same final composition) are analyzed as simple binary data, particular combinations may be found that transform the multicomponent diffusion coefficient matrix D to diagonal form and thus yield time-invariant, pseudo-binary diffusion coefficients: the eigenvalues of D. Since the matrix that diagonalizes D is given by the coefficients used to form the linear combinations, D is easily recovered by the inverse transformation. The advantages of the eigenvalue method are briefly discussed. For testing purposes, ternary diffusion coefficients are determined from conductance measurements for dilute aqueous NaOH + NaCl mixtures. Diffusion of NaOH in aqueous NaCl is significantly more rapid than in pure water, and large coupled flows of NaCl are observed. The results are in close agreement with behavior predicted by Onsager–Fuoss theory.
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Chen, Jinlin, Yiquan Wu, Yeguo Sun i Chunzhi Yang. "Image Encryption Algorithm Using 2-Order Bit Compass Coding and Chaotic Mapping". Symmetry 14, nr 7 (20.07.2022): 1482. http://dx.doi.org/10.3390/sym14071482.
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This paper proposes a novel image encryption algorithm based on an integer form of chaotic mapping and 2-order bit compass diffusion technique. Chaotic mapping has been widely used in image encryption. If the floating-point number generated by chaotic mapping is applied to image encryption algorithm, it will slow encryption and increase the difficulty of hardware implementation. An innovative pseudo-random integer sequence generator is proposed. In chaotic system, the result of one-iteration is used as the shift value of two binary sequences, the original symmetry relationship is changed, and then XOR operation is performed to generate a new binary sequence. Multiple iterations can generate pseudo-random integer sequences. Here integer sequences have been used in scrambling of pixel positions. Meanwhile, this paper demonstrates that there is an inverse operation in the XOR operation of two binary sequences. A new pixel diffusion technique based on bit compass coding is proposed. The key vector of the algorithm comes from the original image and is hidden by image encryption. The efficiency of our proposed method in encrypting a large number of images is evaluated using security analysis and time complexity. The performance evaluation of algorithm includes key space, histogram differential attacks, gray value distribution(GDV),correlation coefficient, PSNR, entropy, and sensitivity. The comparison between the results of coefficient, entropy, PSNR, GDV, and time complexity further proves the effectiveness of the algorithm.
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Li, Hong Ji, Jia Hui Xu, Liu Qing Wang, Dan Dan Hou, Zhi Ru Wang i Hao Zhuo Li. "Adsorption Properties of Modified ATP-RGO Composite Aerogel for Removal of Malachite Green and Methyl Orange from Unitary and Binary Aqueous Solutions". Adsorption Science & Technology 2022 (2.08.2022): 1–18. http://dx.doi.org/10.1155/2022/5455330.
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In this paper, the modified attapulgite-reduced graphene oxide composite aerogel (ATP-RGO CA) was prepared by sol-gel method using modified attapulgite as silica source. The removal of the cationic dye malachite green (MG) and azo dye methyl orange (MO) onto ATP-RGO CA from unitary and binary systems was investigated. Morphology and microstructure studies of ATP-RGO CA were investigated by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area and porosity analysis. Experiments were carried out as a function of pH, contact time, initial dye concentration, and temperature in unitary and binary systems. The adsorption kinetics, isotherms, thermodynamics, and dye desorption were studied in unitary and binary dye systems. The adsorption kinetics was modeled using the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetics equations. The equilibrium adsorption data of MG and MO dyes on ATP-RGO CA were analyzed. Thermodynamic parameters of dye adsorption were obtained. In addition, the regeneration of ATP-RGO CA was studied using dye desorption in unitary and binary dye systems. The adsorption kinetics of the dyes followed pseudo-second-order kinetics. The results indicate that the Langmuir model provides the best correlation of the experimental data. The thermodynamic studies showed that the dye adsorption onto ATP-RGO CA was a spontaneous and endothermic reaction. High desorption of MG and MO showed the regeneration of ATP-RGO CA. It can be concluded that ATP-RGO CA is suitable as an adsorbent material to remove MG and MO dyes from unitary and binary systems.
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Fujikawa, S. I. "Tracer Diffusion of Magnesium in Pseudo-Binary Al-Mg2Si Alloys". Defect and Diffusion Forum 143-147 (styczeń 1997): 403–8. http://dx.doi.org/10.4028/www.scientific.net/ddf.143-147.403.
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Newhouse, Randal, Justine Minish i Gary S. Collins. "Diffusion in Binary and Pseudo-Binary L12 Indides, Stannides, Gallides and Aluminides of Rare-Earth Elements as Studied Using Perturbed Angular Correlation of 111In/Cd". Defect and Diffusion Forum 323-325 (kwiecień 2012): 447–52. http://dx.doi.org/10.4028/www.scientific.net/ddf.323-325.447.
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Diffusional jumps can produce fluctuating electric field gradients at nuclei of jumping atoms. Using perturbed angular correlation of gamma rays (PAC), jumps of probe atoms cause nuclear quadrupole relaxation that can be fitted to obtain the mean jump frequency. An overview is given of the application of this approach to highly ordered intermetallic compounds having the L12(Cu3Au) crystal structure. New results are then presented for jump frequencies of111In/Cd probe atoms in pseudo-binary L12compounds of the forms In3(La1-xPrx) and (In1-xSnx)3La. For the mixed rare-earth system, jump frequencies are found to scale with composition between jump frequencies of the end-member phases In3La and In3Pr. However, for the mixed sp-element system, a large decrease in jump frequency is observed as Sn atoms substitute for In-atoms. This difference in behavior appears to depend on whether atomic disorder is on the diffusion sublattice (In-Sn substitution), as opposed to a neighboring sublattice (La-Pr substitution), whether or not there is a difference in diffusion mechanism between end-member phases, and/or whether or not there is a valence difference between the mixing atoms. All three conditions apply for only (In1-xSnx)3La.
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Lane, D. W., G. J. Conibeer, D. A. Wood, K. D. Rogers, P. Capper, S. Romani i S. Hearne. "Sulphur diffusion in CdTe and the phase diagram of the CdS–CdTe pseudo-binary alloy". Journal of Crystal Growth 197, nr 3 (luty 1999): 743–48. http://dx.doi.org/10.1016/s0022-0248(98)00813-6.
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Barros, Marisa C. F., Ana C. F. Ribeiro, Luís M. P. Verissimo, Derek G. Leaist i Miguel A. Esteso. "Diffusion in ternary aqueous {L-dopa + (NaSO3) -β-cyclodextrin} solutions using the pseudo-binary approximation". Journal of Chemical Thermodynamics 123 (sierpień 2018): 17–21. http://dx.doi.org/10.1016/j.jct.2018.03.014.
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Patescu, Rodica Elena, Claudia Maria Simonescu, Cristian Onose, Teodor Laurentiu Busuioc, Daiana Elena Pasarica i Carmen Deleanu. "Simultaneous Removal of Lead and Nickel Ions from Aqueous Synthetic Solutions by Chitosan Coated Cobalt Ferrite". Revista de Chimie 68, nr 1 (15.02.2017): 1–5. http://dx.doi.org/10.37358/rc.17.1.5376.
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This research study deals with lead and nickel simultaneous removal from aqueous solutions by the use of chitosan coated cobalt ferrite as adsorbent. Batch removal tests were performed in order to establish the main parameters that influence the sorption capacity, removal efficiency and the selectivity of this adsorbent. The values of sorption capacity for lead and nickel experimentally determined are: 56.23 mg/g and respectively 45.11 mg/g. Langmuir and Freundlich adsorption isotherms were used to interpret the sorption experimental data. The kinetic data were explored by pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models. The experimental data were well fitted with the pseudo-second order model for both heavy metals. The main conclusion that can be drawn from this research is that this material can be successfully used for the removal of lead and nickel from binary aqueous solutions and wastewater.
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SAADI, WAFA, SOUAD SOUISSI-NAJAR, MARIEM OTHMAN i ABDELMOTTALEB OUEDERNI. "COPPER ADSORPTION ONTO POMEGRANATE PEEL ACTIVATED CARBON AS A NEW ADSORBENT". Cellulose Chemistry and Technology 57, nr 5-6 (20.07.2023): 657–69. http://dx.doi.org/10.35812/cellulosechemtechnol.2023.57.60.
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Pomegranate peel-based activated carbon was prepared using phosphoric acid impregnation for removing copper ions from aqueous solutions. The activated carbon sample was characterized using N2 adsorption–desorption isotherms, SEM, FTIR, and Boehm titration. Batch adsorption experiments were performed as a function of initial pH, contact time, initial ion concentration and temperature. The metal adsorption was found pH dependent, with maximum adsorption occurring at an initial pH of 5.4. Langmuir, Freundlich and Temkin isotherms were used to analyze the equilibrium data at different temperatures. The Freundlich isotherm was considered to be the best model for representing Cu(II) adsorption data. The kinetic studies were analyzed using pseudo-first order, pseudo-second order and intraparticle diffusion models, with good fitting to the pseudo-second-order model. The adsorption behavior of the binary solution system Cu(II)-Cd(II) showed that the adsorbent has higher selectivity towards copper ions than cadmium ions.
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Abebe, Buzuayehu, i H. C. Ananda Murthy. "Synthesis and Characterization of Ti-Fe Oxide Nanomaterials for Lead Removal". Journal of Nanomaterials 2018 (7.11.2018): 1–10. http://dx.doi.org/10.1155/2018/9651039.
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TiO2-Fe2O3 binary oxides containing different percentage of Fe2O3 were synthesized using impregnation method. The Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and thermogravimetric with differential thermal analyzer (TG-DTA) analytical techniques were used for understanding of the physicochemical properties and well impregnation of Fe2O3 in TiO2 lattice. During adsorption study, pH of the solution, adsorbent dosage, time of contact, agitation speed, and concentration of adsorbate were optimized. From Langmuir, Freundlich, FG, D-RK, Temkin, and FH adsorption isotherm models, relatively, Langmuir isotherm model fits well. For adsorption-reaction kinetic model, pseudo-first order (PFO), pseudo-second order (PSO), and Elovich were tested and intraparticle diffusion (IPD) for adsorption-diffusion kinetic models. Out of those, the PSO fits well; this indicates that the mechanism of adsorption is under control of adsorption-reaction. The mean adsorption energy, spontaneity, and reproducibility of the adsorbent were also conducted, and all of those studies support the domination of physical adsorption mechanism.
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Fathy, Nady A., Ola I. El-Shafey i Laila B. Khalil. "Effectiveness of Alkali-Acid Treatment in Enhancement the Adsorption Capacity for Rice Straw: The Removal of Methylene Blue Dye". ISRN Physical Chemistry 2013 (3.04.2013): 1–15. http://dx.doi.org/10.1155/2013/208087.
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The effectiveness of alkali-acid modification in enhancement the adsorption capacity of rice straw (RS) for removing a basic dye was studied. The obtained adsorbents were characterized by slurry pH, pHPZC, iodine number, methylene blue number, FTIR, and SEM analyses. Adsorption of methylene blue (MB) was described by the Langmuir, Freundlich, Tempkin, and Redlich-Peterson isotherm models. Effects of contact time, initial concentration of MB dye, pH of solution, adsorbent dose, salt concentration of NaCl, and desorbing agents on the removal of MB were reported. Kinetic studies were analyzed using the pseudo-first-order, pseudo-second-order, and the intraparticle diffusion models and were found to follow closely the pseudo-second-order model. Equilibrium data were best represented by the Langmuir and Redlich-Peterson isotherms. The adsorption capacities were varied between 32.6 and 131.5 mg/g for untreated and treated RS samples with NaOH-1M citric acid (ARS-1C), respectively. Adsorption behavior of the ARS-1C sample was experimented in a binary mixture containing methylene blue (basic) and reactive blue 19 (acidic) dyes which showed its ability to remove MB higher than RB19. Overall, the results indicate that the alkali-acid treatment proved to be potential modification for producing effective low-cost adsorbents for the removal of the basic dyes from wastewater.
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Olafadehan, Olaosebikan Abidoye. "Binary Adsorption of Phenol and 2-Chlorophenol on Chitosan Derived from Pink Shrimp Shell". Petroleum & Petrochemical Engineering Journal 6, nr 1 (2022): 1–18. http://dx.doi.org/10.23880/ppej-16000292.
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The binary adsorption of phenol and 2-chlorophenol in a synthetic industrial wastewater was investigated using extracted optimized chitosan from pink shrimp shell wastes as adsorbent. The effects of operational parameters on the binary adsorption system were studied. The equilibrium adsorption data for the binary system were analyzed using extended Langmuir, extended Sips, extended Redlich-Peterson and Fritz-Schlüender adsorption isotherms. The Fritz-Schlüender isotherm fitted the adsorption data excellently wherein the maximum adsorption capacities for phenol and 2-chlorophenol were obtained as 6.7431 and 14.7493 mg/g respectively for the optimized chitosan at pH=4, adsorbent dose of 1 g, initial concentration of phenol and 2-chlorophenol = 25-250 mg/L, contact time of 120 min, agitation speed of 150 rpm, particle size of 250 microns and temperature of (28 ± 2)°C. The kinetic modelling of the phenol-2-chlorophenol adsorption system showed that pseudo second-order kinetic model gave the best fit amongst the investigated kinetic models. The simultaneous adsorption of phenol and 2-chlorophenol on the prepared adsorbent was chemisorption and film-diffusion controlled. The thermodynamic parameters of the binary adsorption system indicated that the simultaneous adsorption of phenol and 2-chlorophenol on the extracted optimized chitosan was relatively favourable, non-spontaneous, endogenic and exothermic with changes in Gibb’s free energy, G ∆ , positive, entropy, S ∆ , approximately zero (though negative), and enthalpy, H∆, negative.
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Chopra, Lalita, Jasgurpreet Singh Chohan, Shubham Sharma, Mariusz Pelc i Aleksandra Kawala-Sterniuk. "Multifunctional Modified Chitosan Biopolymers for Dual Applications in Biomedical and Industrial Field: Synthesis and Evaluation of Thermal, Chemical, Morphological, Structural, In Vitro Drug-Release Rate, Swelling and Metal Uptake Studies". Sensors 22, nr 9 (30.04.2022): 3454. http://dx.doi.org/10.3390/s22093454.
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The hydrogel materials are getting attention from the research due to their multidimensional usage in various fields. Chitosan is one of the most important hydrogels used in this regard. In this paper multifunctional binary graft copolymeric matrices of chitosan with monomer AA and various comonomers AAm and AN were prepared by performing free radical graft copolymerization in the presence of an initiator KPS. The binary grafting can be done at five different molar concentrations of binary comonomers at already optimized concentration of AA, KPS and other reaction conditions such as time, temperature, solvent amount, etc. Various optimum reaction conditions were investigated and presented in this work; the backbone as well as binary grafts Ch-graft-poly (AA-cop-AAm) and Ch-graft-poly (AA-cop-AN) were characterized via various physio-chemical techniques of analysis such as SEM analysis, Xray diffraction (XRD), TGA/DTA and FTIR. In the batch experiments, the binary grafts were investigated for the percent swelling with respect to pH (pH of 2.2, 7.0, 7.4 and 9.4) and time (contact time 1 to 24 h). Uploading and controllable in vitro release of the drug DS (anti-inflammatory) was examined with reverence to gastrointestinal pH and time. The binary grafts showed significantly better-controlled drug diffusion than the unmodified backbone. The kinetic study revealed that the diffusion of the drug occurred by the non-Fickian way. In the case of separation technologies, experiments (batch tests) were executed for the toxic bivalent metal ions Fe (II) and Pb (II) sorption from the aqueous media with respect to the parameters such as interaction period, concentration of fed metal ions in solution, pH and temperature. The binary grafted matrices showed superior results compared to chitosan. The kinetics study revealed that the matrices show pseudo-second order adsorption. The graft copolymer Ch-graft-poly (AA-cop-AAm) provided superior results in sustainable drug release as well as metal ion uptake. The study explored the potential of chitosan-based materials in the industry as well in the biomedical field. The results proved these to be excellent materials with a lot of potential as adsorbents.
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Kalha, C., M. Reisinger, P. K. Thakur, T. L. Lee, S. Venkatesan, M. Isaacs, R. G. Palgrave, J. Zechner, M. Nelhiebel i A. Regoutz. "Evaluation of the thermal stability of TiW/Cu heterojunctions using a combined SXPS and HAXPES approach". Journal of Applied Physics 131, nr 16 (28.04.2022): 165301. http://dx.doi.org/10.1063/5.0086009.
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Power semiconductor device architectures require the inclusion of a diffusion barrier to suppress or at best prevent the interdiffusion between the copper metallization interconnects and the surrounding silicon substructure. The binary pseudo-alloy of titanium–tungsten (TiW), with >70 at. % W, is a well-established copper diffusion barrier but is prone to degradation via the out-diffusion of titanium when exposed to high temperatures ([Formula: see text]400 [Formula: see text]C). Here, the thermal stability of physical vapor deposited TiW/Cu bilayer thin films in Si/SiO[Formula: see text](50 nm)/TiW(300 nm)/Cu(25 nm) stacks were characterized in response to annealing at 400 [Formula: see text]C for 0.5 h and 5 h, using a combination of soft and hard x-ray photoelectron spectroscopy and transmission electron microscopy. Results show that annealing promoted the segregation of titanium out of the TiW and interdiffusion into the copper metallization. Titanium was shown to be driven toward the free copper surface, accumulating there and forming a titanium oxide overlayer upon exposure to air. Annealing for longer timescales promoted a greater out-diffusion of titanium and a thicker oxide layer to grow on the copper surface. However, interface measurements suggest that the diffusion is not significant enough to compromise the barrier integrity, and the TiW/Cu interface remains stable even after 5 h of annealing.
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Lee, Jeong-Yong, Hoejun Heo, Namhyun Kang i Chung-Yun Kang. "Microstructural Evolution of Reaction Layer of 1.5 GPa Boron Steel Hot-Dipped in Al-7wt%Ni-6wt%Si Alloy". Metals 8, nr 12 (15.12.2018): 1069. http://dx.doi.org/10.3390/met8121069.
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The constituents, distribution, and characteristics of the phases formed on the coating layer of boron steel hot-dipped in Al-7wt%Ni-6wt%Si were evaluated in detail. In particular, the microstructure and phase constitution of the reaction layer were characterized. Moreover, the microstructural evolution mechanism of the phase was presented with reference to the (Al-7wt%Ni-6wt%Si)-xFe from the pseudo-binary phase diagram. The solidification layer consisted mainly of Al, Al3Ni, and Si phases. Reaction layers were formed in the order of Al9FeNi(Τ), Fe4Al13(θ), and Fe2Al5(η) from the solidification layer side. In addition, the κ (Fe3AlC) layer was formed at the Fe2Al5(η)/steel interface. From pseudo-binary phase diagram analysis, it was found that Fe4Al13(θ) can form when the Fe concentration is over 2.63 wt% in the 690 °C Al-7wt%Ni-6wt%Si molten metal. When the concentration of Fe increased to 10.0–29.0 wt%, isothermal solidification occurred in the Fe4Al13(θ) and Al9FeNi(Τ) phases simultaneously. Moreover, given that the T phase does not dissolve Si, it was discharged, and the Si phase was formed around the Al9FeNi(T) phase. The Fe2Al5(η) phase was formed by a diffusion reaction between Fe4Al13(θ) and steel, not a dissolution reaction. Moreover, Al2Fe3Si3(τ1) was formed at the Fe4Al13(θ)-Fe2Al5(η) interface by discharging Si from Fe4Al13(θ) without Si solubility. Furthermore, the Fe3AlC(κ) layer was formed by carbon accumulation that discharged in the Fe2Al5(η) region transformed from steel to Fe2Al5(η). The twin regions in the Fe4Al13(θ) and Fe2Al5(η) grain were due to the strains caused by the lattice transformation in the constrained state, wherein the phases are present between the Al9FeNi(Τ) layer and steel.
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Sohaj, Pavel, i Vít Jan. "Local Changes of Microhardness in Dissimilar Weld Joints after High Temperature Exposure". Key Engineering Materials 586 (wrzesień 2013): 249–52. http://dx.doi.org/10.4028/www.scientific.net/kem.586.249.
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The paper presents results obtained during evaluation of dissimilar weld joints of creep-resistant steels. During high temperature exposure of dissimilar weld joints, alloying elements were redistributed across the weld interface. These diffusion effects can cause local changes of microstructure and have a direct effect on local mechanical properties in weld interface area. Carbon and nitrogen have the strongest influence on changes of mechanical properties of steels. . These local changes of mechanical properties have a strong influence on the reliability and the service live of the whole welded structures. The dissimilar joints of the austenitic steel/martenzitic steel type was studied. Laboratory weld joints were prepared and annealed at different temperatures for different time periods. Microhardness profiles across the weld interface were measured and the influence of long-term, high temperature exposure on the changes of local microhardness was evaluated. Results were compared with pseudo-binary phase diagrams and with the literature.
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Shen, Jia-Chao, Hong-Yan Zeng, Bi Foua Claude Alain Gohi i Chao-Rong Chen. "Adsorption Behaviour of Cr(VI) from Ternary Mesoporous Mg/Fe/Al Oxide Using Glucose as a Soft Template". Journal of Nanoscience and Nanotechnology 20, nr 9 (1.09.2020): 5555–62. http://dx.doi.org/10.1166/jnn.2020.17875.
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The ternary mesoporous MgFeAl oxide (MgFeAlO) material was designed and prepared using glucose as a soft template by calcination of its MgFeAl hydrotalcite precursor. The MgFeAlO showed significantly better Cr(VI) adsorption performance than binary MgAlO. The effect of Fe3+ on Cr(VI) removal in simulated wastewater was studied by researching the microstructure, adsorption properties and mechanism of the material. The results showed that the addition of Fe3+ affected the microstructure of MgAlO, where the partial substitution of Al3+ by Fe3+ into the host layers resulted in an increase in the interlayer region and specific area (SBET) as well as an enlargement in mesoporous feature into the MgFeAlO. The Cr(VI) adsorption process, taking place by the reconstruction of the MgFeAlO oxide with water (memory effect) companying with the intercalation of CrO2−4 anions, was much more efficient than that occurring in the binary MgAlO. MgFeAlO’s adsorption of Cr(VI) follows the pseudo-second-order model and it is controlled by intra particle diffusion. The adsorption isotherm was better fitted by the Langmuir model, suggesting that the Cr(VI) adsorption was a monolayer adsorption onto the homogeneous support surface. All thermodynamic and kinetic calculations suggested that the Cr(VI) adsorption process on the MgFeAlO was of chemisorption nature, in which activation energy (Ea) and enthalpy change (ΔH) were 30.01 and 193.58 kJ·mol−1, respectively.
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Finish, Qusay Ghanim, i Tariq Mohammed Naife. "Adsorption Desulfurization of Iraqi Light Naphtha Using Metals Modified Activated Carbon". Journal of Engineering 27, nr 7 (26.06.2021): 24–41. http://dx.doi.org/10.31026/j.eng.2021.07.03.
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The study aims to evaluate the removal of sulfur content from Iraqi light naphtha produced in Al-Dora refinery by adsorption desulfurization DS technique using modified activated carbon MAC loaded with nickel Ni and copper Cu as single binary metals. The experiments were carried in a batch unit with various operating parameters; MAC dosage, agitation speed, and a contact time of 300 min at constant initial sulfur concentration 155 ppm and temperature. The results showed higher DS% by AC/Ni-Cu (66.45)% at 500 rpm and 1 g dosage than DS (29.03)% by activated carbon AC, increasing MAC dosage, agitation speed, and contact time led to increasing DS% values. The adsorption capacity of MAC results was recorded (16, 15, and 20) mg sulfur/g MAC for AC/Ni, AC/Cu and, AC/Ni-Cu, respectively. Equilibrium isotherm study results show good fitting with Freundlich isotherm model with R2 value (0.95) for AC/Ni-Cu. The kinetic study results showed R2 value (0.974, 0.981, and 0.95) by pseudo first order and (0.96, 0.916 and, 0.909) by pseudo second order for AC/Ni, AC/Cu, and AC/Ni-Cu, respectively. The calculated qe(cal) (4.337-4.79) mg/g by first order model was the nearest to the obtained qe(exp) (5.125) mg/g by the experiments where no interparticle diffusion referring to more than one process is controlling the adsorption process of sulfur compounds by MAC.
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Kandlikar, S. G. "Boiling Heat Transfer With Binary Mixtures: Part I—A Theoretical Model for Pool Boiling". Journal of Heat Transfer 120, nr 2 (1.05.1998): 380–87. http://dx.doi.org/10.1115/1.2824260.
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Experimental evidence available in the literature indicates that the pool boiling heat transfer with binary mixtures is lower than the respective mole- or mass-fraction-averaged value. Although a few investigators have presented analytical work to model this phenomenon, empirical methods and correlations are used extensively. In the present work, a theoretical analysis is presented to estimate the mixture effects on heat transfer. The ideal heat transfer coefficient used currently in the literature to represent the pool boiling heat transfer in the absence of mass diffusion effects is based on empirical considerations, and has no theoretical basis. In the present work, a new pseudo-single component heat transfer coefficient is introduced to account for the mixture property effects more accurately. The liquid composition and the interface temperature at the interface of a growing bubble are predicted analytically and their effect on the heat transfer is estimated. The present model is compared with the theoretical model of Calus and Leonidopoulos (1974), and two empirical models, Calus and Rice (1972) and Fujita et al. (1996). The present model is able to predict the heat transfer coefficients and their trends in azeotrope forming mixtures (benzene/methanol, R-23/R-13 and R-22/R-12) as well as mixtures with widely varying boiling points (water/ethylene glycol and methanol/water).
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Deng, Yu, Xiaodong Li, Fuquan Ni, Qiao Liu, Yunpeng Yang, Min Wang, Tianqi Ao i Wenqing Chen. "Synthesis of Magnesium Modified Biochar for Removing Copper, Lead and Cadmium in Single and Binary Systems from Aqueous Solutions: Adsorption Mechanism". Water 13, nr 5 (25.02.2021): 599. http://dx.doi.org/10.3390/w13050599.
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Biochar modification can enhance the properties associated with porosity and functional groups and has been identified as an effective way to improve adsorption capacity. Modified corncob biochars pretreated by different contents of MgCl2 are obtained through slow pyrolysis; then, this work explores the adsorption abilities towards heavy metals. After modification, biochars mainly impregnate carbon surface with Mg(OH)2 and MgO particles. The best mass ratio of magnesium (Mg)/feedback is 15% for modified biochar, and 15%Mg-BC has much higher (2.36–9.34 times) metal sorption capacity than pristine biochar. Batch adsorption experiments show that copper (Cu(II)) and lead (Pb(II)) on adsorbents follow a pseudo-second-order model and cadmium (Cd(II)) follows an intraparticle diffusion model. The adsorption isotherm of Cu(II) fits well with the Langmuir model, and Pb(II) and Cd(II) fit with the Freundlich model. In the binary system, modified biochar still effectively removes metals, but the sorption capacity of metals decreases rapidly because of competitive sorption. The main adsorption mechanisms of metals include surface precipitation, cation π-banding, complexation, and ion exchange. The results show that Mg-modified biochar may be an environmentally friendly material for reducing the water pollution of heavy metals.
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Swaminathan, R., J. Woods, S. Calvin, Joseph Huth i M. E. McHenry. "Microstructural Evolution Model of the Sintering Behaviour and Magnetic Properties of NiZn Ferrite Nanoparticles". Advances in Science and Technology 45 (październik 2006): 2337–44. http://dx.doi.org/10.4028/www.scientific.net/ast.45.2337.
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The sintering of RF plasma synthesized NiZn ferrite nanoparticles was studied. The as-synthesized nanoparticles have been modeled as having a core-shell structure with richer Zn concentration on the surface. Most Zn cations occupy tetrahedral sites typical of zinc ferrites, while some of the Zn cations occupy tetrahedral sites in a (111) oriented surface layer in the form of ZnO. Ni and Fe cations show no evidence of such disorder and their positions are consistent with the bulk spinel structure. This core-shell structure evolves by decomposition of the as-synthesized nanoparticles into Ni-and Zn-rich ferrites followed by the decomposition of the Zn-rich ferrites into ZnO and -Fe2O3 during sintering of the nanoparticles. Within the core region, sintering causes Ni to exit the ferrite structure and be reduced to a metallic form, possibly via a NiO intermediate. The miscibility gap in the pseudo-binary ZnFe2O4/NiFe2O4 system was modeled using equilibrium solution data. Decomposition rates are interpreted considering inter-diffusion kinetics. Sintered nanoparticle compacts showed an evolution of a 4- phase mixture of ferrite + ZnO + -Fe2O3 + Ni with increasing sintering temperature. The average ferrite nanoparticle size is preserved up to very high sintering temperatures. These observations suggest that the ZnO shell contributes to the sintering process by surface diffusion while acting as a barrier to the growth of the ferrite core. Metal edge EXAFS patterns of the sintered compacts confirm that Fe transforms from a single ferrite phase into a mixture of -Fe2O3 and ferrite; ZnO content progressively increases with sintering temperature and elemental Ni evolves from the ferrite with increasing sintering temperature. The saturation magnetization and Curie temperature were observed to decrease as a function of sintering temperature, with an anomaly at the temperature where Ni starts to form. This is explained by Zn diffusing from the core depleting the ferrite and increasing the amount of non-magnetic ZnO in the shell. AC magnetic measurements also vary systematically with the microstructural evolution.
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Lim, Duong Thi, Trinh Ngoc Tuyen, Dao Ngoc Nhiem, Dao Hong Duc, Pham Ngoc Chuc, Nguyen Quang Bac, Dang Xuan Tung i in. "Fluoride and Arsenite Removal by Adsorption on La2O3-CeO2/Laterite". Journal of Nanomaterials 2021 (18.07.2021): 1–13. http://dx.doi.org/10.1155/2021/9991050.
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In the present article, the adsorbent prepared from laterite with lanthanum and cerium oxides (La2O3-CeO2/laterite (LCL)) was efficiently employed for the removal of arsenite and fluoride from an aqueous environment. The obtained materials were characterized by XRD, SEM, and nitrogen adsorption/desorption. The synthesized LCL exhibited a high adsorption capacity towards arsenite (As(III)) and fluoride. The adsorption of both analytes on LCL, which was well-fitted to a pseudo-second-order equation, was found to be kinetically fast in the first 20 minutes and reached equilibrium at around 180 minutes. Weber’s intraparticle diffusion model in multilinearity using the piecewise linear regression combined with Akaike’s criteria was addressed. The adsorption capacities of LCL calculated from Langmuir’s isotherm model were found to be 67.08 mg·g-1 for arsenite and 58.02 mg·g-1 for fluoride. Thermodynamic parameters presented an endothermic nature of arsenite adsorption but an exothermic nature for fluoride and a negative Gibbs free energy for the spontaneous process of arsenite or fluoride adsorption at the studied temperature range. The excellent adsorption performance and stability make the composite of laterite and La-Ce binary oxides an alternative efficient and cheap adsorbent for the removal of arsenite and fluoride in an aqueous solution.
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Sumanjeet, Kaur, Sharma Neeta i Kaur Manpreet. "Single and Competitive Removal of Pb(II) in the Presence of Ni(II) using Polyacrylamide Grafted Rice Husk". Journal of Applied Sciences and Environmental Management 27, nr 1 (31.01.2023): 63–70. http://dx.doi.org/10.4314/jasem.v27i1.10.
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In a quest to find efficient adsorbents for metal ions, studies on various adsorbents for metals have been of interest since the past several decades. The present study is focused on the removal of Pb (II) ions from aqueous solution using poly acrylamide grafted rice husk by batch studies. Industrial waste waters generally contain metals present as mixtures, therefore the effect of Ni (II) on the removal of Pb(II) from mixtures of Pb(II)+Ni(II) ions has also been investigated. The adsorbent has been prepared by the treatment of rice husk with acrylamide in the presence of N,N-methylene bis acrylamide and potassium persulphate. The adsorbent has been characterised by infrared spectral studies. Maximum adsorption obtained is 93% at pH 5, metal ion concentration 300mg/L in 180mins at 298K. Isotherm analyses show that both Langmuir and Freundlich isotherm models are best obeyed. The process is endothermic and spontaneous in nature and follows pseudo first order kinetics. Intraparticle diffusion also occurs but is not the rate determining step. Application of Langmuir competitive model for the binary system shows that adsorption of Pb(II) has been supressed by presence of Ni(II) ions. Studies suggest that the adsorbent is effective and can find industrial applicability.
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Giannoulia, Stefania, Irene-Eva Triantaphyllidou, Athanasia G. Tekerlekopoulou i Christos A. Aggelopoulos. "Mechanisms of Individual and Simultaneous Adsorption of Antibiotics and Dyes onto Halloysite Nanoclay and Regeneration of Saturated Adsorbent via Cold Plasma Bubbling". Nanomaterials 13, nr 2 (13.01.2023): 341. http://dx.doi.org/10.3390/nano13020341.
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Halloysite nanoclay (HNC) was examined as an adsorbent for the individual and simultaneous removal of antibiotic enrofloxacin (ENRO) and methylene blue (MB) from aqueous solutions, alongside its regeneration via cold atmospheric plasma (CAP) bubbling. Initially, batch kinetics and isotherm studies were carried out, while the effect of several parameters was evaluated. Both ENRO and MB adsorption onto HNC was better described by Langmuir model, with its maximum adsorption capacity being 34.80 and 27.66 mg/g, respectively. A Pseudo-second order model fitted the experimental data satisfactorily, suggesting chemisorption (through electrostatic interactions) as the prevailing adsorption mechanism, whereas adsorption was also controlled by film diffusion. In the binary system, the presence of MB seemed to act antagonistically to the adsorption of ENRO. The saturated adsorbent was regenerated inside a CAP microbubble reactor and its adsorption capacity was re-tested by applying new adsorption cycles. CAP bubbling was able to efficiently regenerate saturated HNC with low energy requirements (16.67 Wh/g-adsorbent) in contrast to Fenton oxidation. Most importantly, the enhanced adsorption capacity of the CAP-regenerated HNC (compared to raw HNC), when applied in new adsorption cycles, indicated its activation during the regeneration process. The present study provides a green, sustainable and highly effective alternative for water remediation where pharmaceutical and dyes co-exist.
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Nikic, Jasmina, Malcolm Watson, Aleksandra Tubic, Marijana Kragulj-Isakovski, Snezana Maletic, Emilijan Mohora i Jasmina Agbaba. "Arsenic removal from water using a one-pot synthesized low-cost mesoporous Fe-Mn-modified biosorbent". Journal of the Serbian Chemical Society 84, nr 3 (2019): 327–42. http://dx.doi.org/10.2298/jsc180809099n.
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This paper investigates the removal of arsenic from water using an environmentally friendly modified biosorbent, chitosan coated with Fe?Mn binary oxide (Chit-FeMn), simply prepared with an one-pot low-cost procedure by simultaneous oxidation and coprecipitation. The sorbent was characterized by SEM, EDS, XRD, FTIR, BET specific surface area, and point of zero charge (pHpzc) measurements. The kinetic data fitted a pseudo-second order model for both As(III) and As(V), suggesting chemical adsorption on the sorbent surface and that intra-particle diffusion is not the only rate-limiting step during adsorption. The adsorption isotherms were best fit to the Freundlich model, and the non-monolayer adsorption model for arsenic on Chit-FeMn is therefore proposed. Below pH 9, the effect of pH on As(III) and As(V) removal by Chit-FeMn was insignificant, with As removals remaining above 85 %. Cl- and NO3 - had negligible influences on As(III) and As(V) removal, whereas PO4 3-, SiO3 2-, CO3 2- and SO4 2- were observed to compete with arsenic species for adsorption sites. The adsorbent was successfully applied to remove arsenic from real arsenic contaminated groundwater samples to below 10 ?g L-1 suggesting that Chit-FeMn is a promising candidate for the low cost removal of both As(V) and As(III) during drinking water treatment.
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Ghosh, Uday Chand, Durjoy Bandyopadhyay, Biswaranjan Manna i Manik Mandal. "Hydrous Iron(III)-Tin(IV) Binary Mixed Oxide: Arsenic Adsorption Behaviour from Aqueous Solution". Water Quality Research Journal 41, nr 2 (1.05.2006): 198–209. http://dx.doi.org/10.2166/wqrj.2006.023.
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Abstract Groundwater in the Bengal delta plain is primarily in an anoxic environment and As(III)/As(total) ratios reported are in the range of 0.60 to 0.90. Most of the studied adsorbents showed greater adsorption affinity for less toxic As(V) than for more toxic As(III). The synthesis and physicochemical characterizations of iron(III)-tin(IV) binary mixed oxide composite with systematic arsenic adsorption behaviour are reported here. The parameters studied are the effect of pH, adsorption capacity with varying arsenic loads, contact time for kinetics and isotherm modelling by batch method. In the pH range of 3.0 to 9.0, the adsorption of As(III) is found to be nearly the same while that of As(V) decreases with increasing pH for the studied arsenic concentrations (5.0 to 20.0 mg L-1). The adsorption data were analyzed using various kinetic and isotherm model equations. The rate of adsorption of As(III) was faster than that of As(V) at equilibrium pH ~7.0 and temperature 30(± 2)°C. The adsorption kinetic data for arsenic fitted best with the Ho's pseudo-second order [R2 ~0.99–1.00 for As(III) and ~0.97–0.98 for As(V)] and parabolic diffusion (R2 ~0.98–0.99) equations. The present kinetic data fitted the power function and simple Elovich kinetic equations well (R2 = ~0.97–1.00), except the data obtained for As(III) from the 20.0 mg L-1 solution. The analyses of adsorption data for As(III) and As(V), respectively, at equilibrium pH 6.8(±0.1) and 7.3(±0.1) with three different two-parameter isotherm model equations show the fitting order: Langmuir < Freundlich >Temkin. The monolayer adsorption capacity (θ0, mg g-1) values evaluated from the Langmuir isotherm for As(III) and As(V) are 43.86 and 27.55, respectively.
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Fatima, Bushra, Basem Al Alwan, Sharf Ilahi Siddiqui, Rabia Ahmad, Mohammed Almesfer, Manoj Kumar Khanna, Ruby Mishra, Rangnath Ravi i Seungdae Oh. "Facile Synthesis of Cu-Zn Binary Oxide Coupled Cadmium Tungstate (Cu-ZnBO-Cp-CT) with Enhanced Performance of Dye Adsorption". Water 13, nr 22 (20.11.2021): 3287. http://dx.doi.org/10.3390/w13223287.
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This study reports the synthesis of copper–zinc binary oxide coupled cadmium tungstate through a simple bio-precipitation method followed by calcination at 600 °C and its adsorption application. The characterization analysis reveals that the prepared composite has low particles size (nano-range), high porosity, and functional groups on the surface. The calcination of sample at 600 °C causes some essential function groups to disappear on the surface. Prepared composite was found to be effective adsorptive material to treat Congo red dye in aqueous solution. 2.5 g L−1 dose of adsorbent could remove more than 99% Congo red dye from 10 mg L−1 solution and more than 80% Congo red dye from 60 mg L−1 aqueous solution. The maximum adsorption capacity of present adsorbent was calculated to be 19.6 mg Congo red per gram of adsorbent. Isotherms analysis suggested a physio-chemical adsorption process. Thermodynamic analysis revealed a exothermic and feasible adsorption process. Adsorption rate was well explained by pseudo second order kinetics. The rate determining step was intra-particle diffusion evaluated from the Weber-Morris plot. To assess the adsorption performance of present adsorbent for Congo red dye the partition coefficient and adsorption equilibrium capacity were compared with other adsorbents. The partition coefficient and adsorption equilibrium values for 10 mg L−1 aqueous solution were found to be approximately 83.3 mg g−1 µM−1 and 4.0 mg g−1 at 30 °C and 7.0 pH using 2.5 g L−1 adsorbent. The value of partition coefficient was found to be higher than previous reported zinc oxide coupled cadmium tungstate having partition coefficient = as 21.4 mg g−1 µM−1 at 30 °C and 7.0 pH using 2.0 g L−1 adsorbent. These results suggested that present adsorption technology is efficient for wastewater treatment.
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Alghamdi, Abdulaziz G., i Zafer Alasmary. "Efficient Remediation of Cadmium- and Lead-Contaminated Water by Using Fe-Modified Date Palm Waste Biochar-Based Adsorbents". International Journal of Environmental Research and Public Health 20, nr 1 (1.01.2023): 802. http://dx.doi.org/10.3390/ijerph20010802.
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Heavy metals pollution of water resources is an emerging concern worldwide and seeks immediate attention. Date palm waste was transformed into biochar (BC), which was further modified through Fe-intercalation for the production of magnetic biochar (Fe-BC) in this study. The produced BC and Fe-BC were analyzed for chemical, proximate, surface, and elemental composition. The efficiency of the produced adsorbents to decontaminate the water from Cd2+ and Pb2+ ions was investigated through kinetics and an isotherm adsorption batch trial. Kinetics adsorption data fit well with the pseudo-second order and power function model, while equilibrium data were described well with the Langmuir and Freundlich isotherms. The maximum adsorption capacity as shown by the Langmuir model was the highest for Fe-BC for both Cd2+ (48.44 mg g−1) and Pb2+ (475.14 mg g−1), compared with that of BC (26.78 mg g−1 Cd2+ and 160.07 mg g−1 Pb2+). Both materials showed higher removal of Pb (36.34% and 99.90% on BC and Fe-BC, respectively) as compared with Cd (5.23% and 12.28% on BC and Fe-BC, respectively) from a binary solution. Overall, Fe-BC was more efficient in adsorbing both of the studied metals from contaminated water. The application of Fe-BC resulted in 89% higher adsorption of Cd2+ and 197% higher adsorption of Pb2+ from aqueous media as compared to BC. Kinetics and isotherm models as well as SEM–EDS analysis of the post-adsorption adsorbents suggested multiple adsorption mechanisms including chemisorption, pore-diffusion, and electrostatic interactions.
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THOMAS, R., P. DAVIDSON, A. RERICHA i D. K. VOZNYAK. "Water-Rich Melt Inclusion as "Frozen" Samples of the Supercritical State in Granites and Pegmatites Reveal Extreme Element Enrichment Resulting Under Non-Equilibrium Conditions". Mineralogical Journal 44, nr 1 (2022): 3–15. http://dx.doi.org/10.15407/mineraljournal.44.01.003.
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In this contribution, we show that in miarolitic pegmatites during the crystallization of water-rich melts, samples of these mineral-forming melts were trapped in the form of water-rich melt inclusions, preserved primarily in quartz. The bulk concentration of water and the temperature are the system-determining parameters since from their analysis it follows that these melt inclusions depict pseudo-binary solvus curves in the coordinates of temperature and water concentration. Furthermore, using reduced coordinates (H2O/H2Ocrit vs. T/Tcrit) most melt inclusions of the studied pegmatites plot very well in a standardized and reduced solvus curve. The existence and formation of such uniform solvus curves is an expression of crystallization processes under nearly equilibrium conditions. However, many trace and some principal elements of the melt inclusions trapped near the solvus crest [H2O/H2Ocrit from 0.5 to 1.5 and T/Tcrit > 0.95] show unusual distributions, with very well-defined Gaussian and/or Lorentzian curves, characterized by defined area, width, offset, and height. This has been shown in many natural examples obtained from pegmatites. Only the offset values represent near-equilibrium conditions and corresponding element concentrations, which are equivalent to the regional Clarke number (Clarke number or Clark is the relative abundance of a chemical element, typically in the Earth's crust). We interpret these distributions as explanation for some extraordinary-chemical properties in this critical region: principally extremely high diffusion rates, low dynamic viscosity and extremely low surface tension. Near the critical point, we have both space and time-related non-equilibrium and equilibrium processes close together. Furthermore, we can show that the Gaussian and Lorentzian distribution are first approximations of the specific element distribution because at the critical point the enrichment of some elements reaches such an extent that the Gaussian and/or Lorentzian curves degenerate into a vertical line (are asymptotic to the concentration axis), which is determined by the maximum solubility of a species in the supercritical melt-water system. The highest concentration of Be, as an example, was observed in Ehrenfriedersdorf melt inclusions: 71490 ppm Be.
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Ivanovska, Aleksandra, Biljana Dojčinović, Jelena Lađarević, Leposava Pavun, Dušan Mijin, Mirjana Kostić i Milica Svetozarević. "Recovering the Soybean Hulls after Peroxidase Extraction and Their Application as Adsorbent for Metal Ions and Dyes". Adsorption Science & Technology 2023 (22.02.2023): 1–17. http://dx.doi.org/10.1155/2023/8532316.
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This study is aimed at extending the soybean hulls’ lifetime by their utilization as an adsorbent for metal ions (Cd2+ and Cu2+) and dyes (Reactive Yellow 39 (RY 39) and Acid Blue 225 (AB 225)). ATR-FTIR spectroscopy, FE-SEM microscopy, and zeta potential measurements were used for adsorbent characterization. The effect of the solution’s pH, peroxidase extraction, adsorbent particle size, contact time, the pollutant’s initial concentration, and temperature on the soybean hulls’ adsorption potential was studied. Before peroxidase extraction, soybean hulls were capable of removing 72% Cd2+, 71% Cu2+ (at a pH of 5.00) or 81% RY 39, and 73% AB 225 (at a pH of 3.00). For further experiments, soybean hulls without peroxidase were used for several reasons: (1) due to their observed higher metal ion removal, (2) in order to reduce the waste disposal cost after the peroxidase (usually used for wastewater decolorization) extraction, and (3) since the soybean hulls without peroxidase possessed significantly lower secondary pollution than those with peroxidase. Cd2+ and Cu2+ removal was slightly increased when the smaller adsorbent fraction (710-1000 μm) was used, while the adsorbent particle size did not have an impact on dye removal. After 30 min of contact time, 92% and 88% of RY 39 and AB 225 were removed, respectively, while after the same contact time, 80% and 69% of Cd2+ and Cu2+ were removed, respectively. Adsorption of all tested pollutants follows a pseudo-second-order reaction through the fast adsorption, intraparticle diffusion, and final equilibrium stage. The maximal adsorption capacities determined by the Langmuir model were 21.10, 20.54, 16.54, and 17.23 mg/g for Cd2+, Cu2+, RY 39, and AB 225, respectively. Calculated thermodynamic parameters suggested that the adsorption of all pollutants is spontaneous and of endothermic character. Moreover, different binary mixtures were prepared, and the competitive adsorptions revealed that the soybean hulls are the most efficient adsorbent for the mixture of AB 225 and Cu2+. The findings of this study contribute to the soybean hulls’ recovery after the peroxidase extraction and bring them into the circular economy concept.
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Terashima, Shinichi, i Tsutomu Sasaki. "Prediction of Intermetallic Compound Formation Sequences in Pseudo Binary Diffusion Couples: Experimental Examinations for (Sn-xZn)/Cu (x = 2, 5, 10, 15, 20 and 25 mass%) by a Kinetic Model with Thermodynamic Data Using MDR Diagram". MATERIALS TRANSACTIONS 55, nr 11 (2014): 1750–54. http://dx.doi.org/10.2320/matertrans.m2014151.
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XU, DAOLIN, i CHIN YI CHEE. "CHAOTIC ENCRYPTION WITH TRANSIENT DYNAMICS INDUCED BY PSEUDO-RANDOM SWITCHING KEYS". International Journal of Bifurcation and Chaos 14, nr 10 (październik 2004): 3625–31. http://dx.doi.org/10.1142/s0218127404011594.
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A chaotic encryption method is proposed for digital communication using a pseudo-random switching key in which parameters irregularly adjust to a rule related to chaotic variables. The scheme derived two features — pseudo-random false switching events are densely produced to mask up binary switching and the transmitted signal possesses a transient nature thus diffusing any deterministic characteristics used by interceptors. The robustness of synchronization is discussed when the mismatch of parameters or keys occurs under erratic switching events.
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Kumar, Hemanth, Neelamegan Esakkiraja, Anuj Dash, Aloke Paul i Saswata Bhattacharyya. "Utilising physics-informed neural networks for optimisation of diffusion coefficients in pseudo-binary diffusion couples". Philosophical Magazine, 25.07.2023, 1–21. http://dx.doi.org/10.1080/14786435.2023.2237900.
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Li, Yang, JunJie Yan, JinShi Wang i GuoXiang Wang. "A Semi-Empirical Model for Condensation Heat Transfer Coefficient of Mixed Ethanol-Water Vapors". Journal of Heat Transfer 133, nr 6 (2.03.2011). http://dx.doi.org/10.1115/1.4003433.
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A semi-empirical model describing the heat transfer characteristics of the pseudo-dropwise condensation of binary vapor on a cooled vertical tube has been formulated. By ignoring the thin film always present on the condensation surface and the intensification of mass transfer caused by the Marangoni effect, the heat transfer characteristics of pseudo-dropwise condensation are tentatively formulated. The model involved an analysis of the diffusion process in the vapor boundary layer along with the heat transfer process through the condensate drops. This model was applied to the condensation of the saturated binary vapor of ethanol and water, and was examined using experimental data at vapor pressure values of 101.33 kPa (provided by Utaka and Wang, 2004, “Characteristic Curves and the Promotion Effect of Ethanol Addition on Steam Condensation Heat Transfer,” Int. J. Heat Mass Transfer, 47, pp. 4507–4516), 84.52 kPa and 47.36 kPa. Calculations using the model show a similar trend to the experimental measurements. With the change of the vapor-to-surface temperature difference, the heat transfer coefficients revealed nonlinear characteristics, with the peak values under all ethanol mass fractions of binary vapor. The heat transfer coefficients increased with decreasing ethanol mass fraction.
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Shi, Bill Q., i Andrew W. Cumming. "Domain Growth and Wetting in a Low Molecular Weight Binary Fluid System". MRS Proceedings 237 (1991). http://dx.doi.org/10.1557/proc-237-97.
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AbstractWe present the results of phase-separation experiments performed on the pseudo-binary fluid system guaiacol-glycerol-water. Elastic light scattering and optical microscopy were used to follow the phase-separation after quenches into the coexistence region of the phase diagram. For critical quenches, we observed the well known bicontinuous infinite cluster morphology normally associated with spinodal decomposition, but with two distinct growth modes. In the bulk, at early times we observed L(t) ∼ t1/3 consistent with diffusion driven dynamics, crossing over to L(t) ∼ t1 at later times, as hydrodynamics became important. Near the sample walls, there obtained a novel fast growth with L(t) ∼ t3/2, just as in the case of recent studies with polymer blends, inconsistent with either diffusion or interface driven dynamics. We attribute this large exponent to wetting effects, and the observation of the same phenomenon in such disparate systems as polymer blends and polar organic solvents is strong evidence that the phenomenon is generic to binary systems.
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Kumar, Hemanth, Neelamegan Esakkiraja, Anuj Dash, Aloke Paul i Saswata Bhattacharya. "A Physics-Informed Neural Networks Based Numerical Inverse Method in Correlation to Estimated Diffusion Coefficients in Pseudo-Binary Diffusion Couples". SSRN Electronic Journal, 2021. http://dx.doi.org/10.2139/ssrn.3953180.
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Khajavian, Mohammad, David A. Wood, Ahmad Hallajsani i Nasrollah Majidian. "Simultaneous biosorption of nickel and cadmium by the brown algae Cystoseria indica characterized by isotherm and kinetic models". Applied Biological Chemistry 62, nr 1 (15.11.2019). http://dx.doi.org/10.1186/s13765-019-0477-6.
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AbstractBiosorption is an effective way of extracting heavy metal ions from aqueous solutions of various compositions. The brown algae, Cystoseria indica, when treated with sodium chloride, demonstrates significant capacity to extract cadmium and nickel, simultaneously, from aqueous solutions. The batch system was running over wide ranges of initial metal ion concentrations (5–150 mg/L), pH (2–6), adsorbent mass (1–4 g/L), and contact times (20–300 min), at a temperature of 25 °C. The results obtained when applying the system in these conditions exhibit higher removal capacities for cadmium than nickel. The optimal conditions of the biosorption process were found as the adsorbent mass of 1 g/L, initial concentration of adsorbates of 100 mg/L and pH of 6. The equilibrium data obtained are better described by the extended-Freundlich isotherm for nickel and cadmium. The maximum biosorption of nickel and cadmium in binary-metal-component system were 18.17 and 55.34 mg/g, respectively. The kinetic data derived from these experiments were evaluated with pseudo-first-order, pseudo-second-order and intra-particle-diffusion kinetic models. Kinetic examination of the equilibrium data derived from these models suggest that the adsorption of nickel and cadmium both follow the intra-particle-diffusion kinetic model.
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Guo, Jia, Weikai Sun, Cheng Dong, Zengjie Wu, Xiaoli Li, Ruizhi Zhou i Wenjian Xu. "Intravoxel incoherent motion imaging combined with diffusion kurtosis imaging to assess the response to radiotherapy in a rabbit VX2 malignant bone tumor model". Cancer Imaging 22, nr 1 (5.09.2022). http://dx.doi.org/10.1186/s40644-022-00488-w.
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Abstract Purpose To combine intravoxel incoherent motion (IVIM) imaging and diffusion kurtosis imaging (DKI) parameters for the evaluation of radiotherapy response in rabbit VX2 malignant bone tumor model. Material and methods Forty-seven rabbits with bone tumor were prospectively enrolled and divided into pre-treatment, considerable effect and slight effect group. Treatment response was evaluated using IVIM-DKI. IVIM-based parameters (tissue diffusion [Dt], pseudo-diffusion [Dp], perfusion fraction [fp]), and DKI-based parameters (mean diffusion coefficient [MD] and mean kurtosis [MK]) were calculated for each animal. Corresponding changes in MRI parameters before and after radiotherapy in each group were studied with one-way ANOVA. Correlations of diffusion parameters of IVIM and DKI model were computed using Pearson’s correlation test. A diagnostic model combining different diffusion parameters was established using binary logistic regression, and its ROC curve was used to evaluate its diagnostic performance for determining considerable and slight effect to malignant bone tumor. Results After radiotherapy, Dt and MD increased, whereas fp and MK decreased (p < 0.05). The differences in Dt, fp, MD, and MK between considerable effect and slight effect groups were statistically significant (p < 0.05). A combination of Dt, fp, and MK had the best diagnostic performance for differentiating considerable effect from slight effect (AUC = 0.913, p < 0.001). Conclusions A combination of IVIM- and DKI-based parameters allowed the non-invasive assessment of cellular, vascular, and microstructural changes in malignant bone tumors after radiotherapy, and holds great potential for monitoring the efficacy of tumor radiotherapy.
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Bermudez-Graterol, J. M., i R. Skoda. "Numerical simulation of bubble dynamics and segregation in binary heptane/dodecane mixtures". Journal of Fluid Mechanics 947 (17.08.2022). http://dx.doi.org/10.1017/jfm.2022.636.
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A mathematical model for the simulation of spherical bubble dynamics in binary alkane mixtures is presented. Detailed heat and mass transfer and phase transition are resolved, and air absorption and desorption are considered. As example mixtures, high-volatile heptane and low-volatile dodecane are investigated. The low-volatile component shows a convective counter-intuitive mass transport opposite to the diffusion flux. A staggered mass flux of heptane and dodecane is associated with a local segregation of mixture components in the surrounding liquid and a distinctive species distribution within the bubble. A comparative study with a pseudo-fluid where alkane species interdiffusion is absent and whose components cannot segregate reveals that for an oscillating bubble, the local segregation hardly affects bubble dynamics, while for a continuously growing bubble in a superheated liquid, the growth rate is considerably affected, particularly for a low heptane mixture percentage. This study demonstrates limitations of treating mixtures by a single-component surrogate fluid and may serve as a starting point for the development of multi-component cavitation models for computational fluid dynamics applications in real fluid mixtures as, e.g. fuels or hydraulic oils.
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Attia, L. A., i H. S. Hassan. "Tracking the adsorptive effect of nano silicate–ginkgo residue composite for Sr(II) and Cd(II) removal from aqueous solutions". International Journal of Environmental Science and Technology, 1.06.2022. http://dx.doi.org/10.1007/s13762-022-04265-x.
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AbstractGinkgo biloba (Ginkgo)/calcium silicate nanocomposite (NG-CSA) was prepared as a novel sorbent. Nanomaterial was characterized using different techniques such as Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, differential thermal analysis and thermal gravimetric analysis (DTA and TG). Adsorption of Sr(II) and Cd(II) ions was performed taking into account significant parameters such as initial pH of the solution, shaking time and initial concentration of metal ions as well as temperature. The acquired results were disclosed that the adsorption of both ions is notably improved using NG-CSA composite. The monolayer capacity of NG-CSA for Sr(II) and Cd(II) from binary system is 122.45 and 64.68 mg/g for Sr(II) and Cd(II), respectively. The kinetic studies exposed that the adsorption process followed nonlinear pseudo-first-order model. The isotherm studies show that the extended Langmuir model is more applicable than Freundlich model for binary system adsorption process. The value of diffusion coefficient for the Sr(II) and Cd(II) is in range 10−10 m2/s which indicates the chemisorption nature of the process. The maximum value of desorption for the Sr(II) and Cd(II) is 98.41% and 97.66 utilized 0.3 M of nitric acid. This indicated that NG-CSA composite can be regenerated and reused for further adsorption of Sr(II) and Cd(II) from wastewater.
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Hassan, Reham S., Soad Elsayed Rizk i Mahmoud G. Hamed. "Synthesis of N-isopropyl acrylamide copolymerized acrylic acid caped with Dibenzo-18-crown-6 composite for selective separation of Co-60 radioisotope from radioactive liquid waste containing Cs-137". Polymer Bulletin, 31.12.2022. http://dx.doi.org/10.1007/s00289-022-04658-5.
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AbstractA new selective polymeric composite capped with crown ether was successfully synthesized using N-isopropyl acrylamide copolymerized acrylic acid paired with Dibenzo-18-crown-6, P(NIPAm-Co-AA-DB 18C-6), by Gamma irradiation and ultrasonic homogenizer polymerization. Scanner electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering were used to characterize the selected polymeric composite's chemical and physical constitution. SEM shows a rough irregular surface, and FTIR spectra confirmed the function groups of P(NIPAm-Co-AA-DB 18C-6). Moreover, a systematic study of monomer and crown ether concentration was investigated to enhance the composite's performance. The behavior of the synthetic composite toward the selective separation of Co-60 from Cs-137 in a binary system was evaluated. Effects of pH, contact time, and initial ion concentration were investigated in a batch mode and the maximum capacity reached 108.0 mg/g for Co-60 and 82.0 mg/g for Cs-137. Four Kinetic models were investigated (pseudo-first-order, pseudo-second-order, Elovich, and Intra-particle diffusion). Regarding the calculated parameters, pseudo-second-order and Elovich models are the most describing the sorption process, indicating the chemisorptions process. Six adsorption isotherms were examined, two-parameter models (Langmuir, and Freundlich) and three-parameter models (Redlich-Peterson, Khan, Sips, and Hills). The best-fitted isotherm was identified using three error methodological approaches: the correlation coefficient (R2), the chi-square test (χ2), and the root-mean-square error. Isotherm models fit the experimental values in the following sequence: Khan > Rdlish-Peterson > Hills > Sips. Finally, an application for column separation was conducted, and Co-60 was completely separated from Cs-137 by 0.1 M HNO3. These findings indicate promising applications in the successive separation of Co-60 from radioactive liquid waste containing Cs-137 from Egyptian reactors. Graphical abstract
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Aswal, D. K., M. Shinmura, Y. Hayakawa i M. Kumagawa. "In-Situ High Temperature Optical Microscopic Observations of Crystallization Mechanism in NdBa2Cu3Ox". MRS Proceedings 569 (1999). http://dx.doi.org/10.1557/proc-569-133.
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ABSTRACTThe pseudo-binary NdBa2Cu3O-Ba3Cu10O13phase diagrams and the crystallization of NdBa2Cu3Ox have been in-situ observed using high-temperature optical microscopy in air and under three different reduced oxygen atmospheres namely, 1%, 0.1% and 0.0097% oxygen in argon. The liquidus line was found to become narrower both in composition and temperature with reducing oxygen content in the atmosphere. These results suggested that while in air NdBa2Cu3Ox can be crystallized from both high-temperature solution and peritectic melt; under reduced oxygen atmospheres the crystallization of NdBa2Cu3Ox is only possible from a peritectic melt. The in-situ observations of crystallization of NdBa2Cu3Ox from high-temperature solutions revealed that the growth mechanism changes from 3D via 2D layer-by-layer to continuos dendritic growth with increasing cooling rate. On the other hand, the NdBa2Cu3Ox crystallization from a peritectic melt involved two distinct steps (i) conversion of Nd4Ba2Cu2Ox into NdBa2Cu3Ox and (ii) nucleation and growth of NdBa2Cu3Ox The growth morphology in this case was independent of the cooling rate. This result and the direct observation of the dissolution of Nd4Ba2Cu2Ox into the liquid suggested that the solute diffusion is the rate-limiting factor.
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Al-Badaani, Arwa A., Awatief F. Hifney, Mahmoud S. Adam i Mohamed Gomaa. "Low-cost biosorption of Fe(II) and Fe(III) from single and binary solutions using Ulva lactuca-derived cellulose nanocrystals-graphene oxide composite film". Scientific Reports 13, nr 1 (19.04.2023). http://dx.doi.org/10.1038/s41598-023-33386-7.
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AbstractThe marine algal biomass of Ulva lactuca was utilized for the extraction of cellulose and the development of cellulose nanocrystals/graphene oxide film. Cellulose nanocrystals with 50–150 nm were produced by H2SO4 hydrolysis of the algal cellulose. The adsorption efficiency of the nanocomposite film for Fe(II) and Fe(III) ions was successfully evaluated using Box-Behnken design. The maximum removal for Fe(II) (64.15%) could be attained at pH 5.13, adsorbent dosage 7.93 g L−1 and Fe(II) concentration 15.39 mg L−1, while the biosorption of Fe(III) was 69.92% at pH 5.0, adsorbent dosage 2 g L−1, and Fe(III) concentration 15.0 mg L−1. However, in the binary system, the removal efficiency of Fe(II) was enhanced to 95.48% at Fe(II):Fe(III) ratio of 1:1, while the Fe(III) removal was increased to 79.17% at ratio 1:2. The pseudo-second-order kinetics exhibited better fitting to the experimental results of Fe(II) and Fe(III) adsorption in both single and binary systems. The intra-particle diffusion was prominent during the biosorption, but the effect of the external mass transfer was significant. The Langmuir, Freundlich, Langmuir–Freundlich, Temkin, and Dubinin-Radushkevich isotherms showed satisfactory fitting to the experimental data, but they differ in priority based on iron state and pH. The adsorption of Fe(II) in the presence of Fe(III) in a mixture was best represented by the extended Langmuir model, while the extended Langmuir–Freundlich model best fitted the adsorption of Fe(III). The FT-IR analysis indicated that physisorption through electrostatic interaction/complexation is the predominant mechanism for the adsorption of iron using the nanocomposite film.