jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Riyadh M. Motny | Michael E. Woods | Supathorn Phongikaroon
Source: Nuclear Technology (article, 2020-04-01)
Field: Materials Science — Materials Chemistry

Assessment of Leaching Characteristics for Cerium and Cesium as Surrogates for Radioactive Materials The leaching behavior of cerium and cesium from different mixtures of rapid setting cement (RSC) with deionized water (DIW) and artificial seawater (ASW) under both dynamic and static leach conditions was investigated according to the method in American National Standard ANSI/ANS-16.1-2003. The leachate solution was collected, diluted with HNO3, and analyzed using inductively coupled plasma–mass spectrometry after leaching periods of 2, 7, and 24 h and 2, 3, 4, 5, 14, 28, 43, and 90 days. Two models [the first-order reaction model (FRM) and the diffusion model (DM)] and their combination [the first-order reaction/diffusion model (FRDM)] were fitted to assess the leaching parameters and identify the type of immobilized radionuclides in the RSC matrix. The result indicated that leaching of 140Ce and 133Cs from the RSC matrices with DIW and ASW under both dynamic and static leach conditions was less than 20% and suggested that the leaching behavior of 140Ce and 133Cs approximated that of a semi-infinite medium. The leaching phenomena of 140Ce and 133Cs could not be fully represented with a single model (the FRM and the DM), and the FRDM was best fitted to these experimental data sets. Overall, the average leachability index L values for 140Ce and 133Cs were greater than the minimum limit indicating their acceptance for disposal recommended by the International Atomic Energy Agency. It could also be stated that RSC with DIW or ASW had a potential for immobilizing radioactive materials. Leaching (pedology) ; Leachate ; Caesium ; Radionuclide ; Seawater ; Cerium ; Radioactive waste ; Chemistry ; Actinide ; Radiochemistry ; Environmental science ; Nuclear chemistry ; Environmental chemistry ; Inorganic chemistry ; Soil science ; Geology Nuclear materials and radiation effects ; Chemical Synthesis and Characterization ; Magnesium Oxide Properties and Applications
Authors: Mohamed Bilal Goudjil | Nabila Sid | Asma Omar Ayachi | Souad Zighmi | Djamila Hamada | Zineb Mahcène | Salah Eddine Bencheikh | Segni Ladjel
Source: Asian Journal of Research in Chemistry (article, 2020-01-01)
Field: Chemistry — Organic Chemistry

Textile Dye removal by Adsorption on Olive Grain as Solid Waste from the Olive Oil Extraction This study is part of the framework for the enhancement of agro-food waste ( olive grains) for the adsorption of a cationic dye by two methods, the first is to use its waste in a natural form (biosorbent) and the second is to the preparation and characterization chemically of an activated carbon from grain by using an activating agent (nitric acid), we studied the influence of several parameters (concentration of methylene blue, mass of olive grains, pH and temperature). The kinetic data was modeled by pseudo first order equations, pseudo-second order and intraparticle diffusion model; The Langmuir-Freundlich model was chosen for the representation of the experimental results. The experimental results are shown that the effect of the mass of adsorbent on the adsorption capacity increased respectively with increasing the mass of adsorbent and dye adsorption is promoted in a room temperature. Modeling results showed that the adsorption of methylene blue on olive grain follows the second order pseudo model for all concentrations in both adsorption and bio-sorption. The study of the isotherm shows that the Langmuir model well describes the process of adsorption of methylene blue on olive grains. All these results show that olive grains could use effectively as a low-cost adsorbent for the removal of cationic dye of an aqueous solution. Olive oil ; Adsorption ; Pulp and paper industry ; Textile ; Extraction (chemistry) ; Municipal solid waste ; Waste management ; Chemistry ; Palm oil ; Environmental science ; Materials science ; Chromatography ; Food science ; Organic chemistry ; Composite material ; Engineering Edible Oils Quality and Analysis
Authors: Lorena Alcaraz | Dayana Nathaly Saquinga | Floralba López | Lola De Lima | Francisco José Alguacil | E. Escudero | Félix A. López
Source: Preprints.org (preprint, 2020-10-22)
Field: Materials Science — Biomaterials

Application of a Low-Cost Cellulose-Based Bioadsorbent for the Effective Recovery of Terbium Ions from Aqueous Solutions Preparation of a low-cost cellulose-based bioadsorbent from the cellulosic material extracted from the rose stems (CRS) was carried out; rose stems were considered agricultural wastes. After the required pretreatment of this waste, and its further treatment with an acidic mixture of acetic and nitric acids, the CRS product was yielded. The resulting bioadsorbent was characterized by several techniques, such as X-ray diffraction, which revealed diffraction maxima related to cellulose structure, whose calculated crystallinity index (CrI) was 75 %. In addition, Fourier Transform Infrared spectroscopy (FTIR), 13C Nuclear Magnetic Resonance (NMR), and X-ray Photoelectron Spectroscopy (XPS) showed signs of acetylation of the sample, also, the thermal properties of the solid was evaluated through Thermogravimetric Analysis (TGA). Scanning Electron Microscopy (SEM) showed cellulose fibers before and after the adsorption process, some particles with not regular shapes were also observed. The CRS bioadsorbent was used in the effective adsorption of valuable Tb(III) from aqueous solution. The adsorption data resulted in a better fit to the Freundlich isotherm, and pseudo-second-order kinetic models; however, chemisorption had not been ruled out. Finally, desorption experiments revealed a recovery of terbium ions with an efficiency of 97 % from terbium-loaded bioadsorbent. Terbium ; Thermogravimetric analysis ; Aqueous solution ; Adsorption ; Cellulose ; Fourier transform infrared spectroscopy ; Chemistry ; Crystallinity ; Freundlich equation ; X-ray photoelectron spectroscopy ; Desorption ; Nuclear chemistry ; Materials science ; Inorganic chemistry ; Analytical Chemistry (journal) ; Chemical engineering ; Ion ; Organic chemistry ; Crystallography Advanced Cellulose Research Studies
Authors: Gehad Abd El-Aziz Mohamed | Eman kamal | Inas. A. El-Sabbagh
Source: Egyptian Journal of Chemistry (article, 2020-12-07)
Field: Chemistry — Inorganic Chemistry

Highly efficient capture of Th(IV) from aqueous solutions using GO/TiO2 nanocomposite An adsorbent GO/TiO2 nanocomposite has been synthesized and characterized. FTIR, XRD, TGA, TEM, SEM and EDX were used to characterize the prepared composite. In a batch method, the adsorption properties of the prepared composite against thorium ions were examined. Th(IV) adsorption kinetics study on GO/TiO2 suggests that the adsorption equilibrium attained within 240 min and depends on the pH value. The adsorption results were expressed mathematically by using Langmuir and Freundlich sorption models. The nanocomposite showed the highest Th(IV) adsorption of 292.32 mg/g at pH 2.5 and 25 oC. The thermodynamic results indicated a thermodynamically favorable, random and exothermic nature of the adsorption process. The obtained results demonstrate that GO/TiO2 nanocomposite can be regarded as a fast, effective and convenient water-based adsorbent for adsorption of Th(IV). This study suggests that nanocomposite can be a promising candidate for the removal of Th(IV) from aqueous solution. Adsorption ; Nanocomposite ; Aqueous solution ; Freundlich equation ; Sorption ; Langmuir ; Composite number ; Fourier transform infrared spectroscopy ; Materials science ; Langmuir adsorption model ; Nuclear chemistry ; Chemical engineering ; Chemistry ; Composite material ; Organic chemistry Radioactive element chemistry and processing ; Extraction and Separation Processes ; Chemical Synthesis and Characterization
Authors: Sally S. Muhammad
Source: Science Journal of Chemistry (article, 2020-01-01)
Field: Chemistry — Inorganic Chemistry

Uranium Sorption Using Lewatit MonoPlus M500 from Sulphate Media The present work has focused on the uptake behavior of uranium (VI) from sulfuric acid media by using Lewatit MonoPlus M500 resin. The influence of parameters, namely pH, U (VI) initial concentration, contact time and temperature were investigated. The optimum conditions were explicated via the sorption kinetics, the isotherm models and the thermodynamic data to determine the behavior of the uranium adsorption. The studied resin is an efficient sorbent for U (VI) ions with maximum sorption capacity q<sub>max</sub> 181.82 mg g<sup>-1</sup> and agreed with both the pseudo-second order kinetic model and Langmuir isotherm. Thermodynamic characteristics showed that the process was spontaneous (ΔG° < 0) and exothermic (ΔH° < 0) in nature. Finally, by application of the results to increase the uranium assay and purity in the working impure uranium concentrate which produced at Gattar pilot plant, Egypt. The assay increase from about 36% up to 71%, while the purity up to 94%. Uranium ; Sorption ; Sorbent ; Langmuir adsorption model ; Sulfuric acid ; Chemistry ; Adsorption ; Nuclear chemistry ; Exothermic reaction ; Kinetics ; Inorganic chemistry ; Materials science ; Organic chemistry ; Metallurgy Radioactive element chemistry and processing ; Chemical Synthesis and Characterization ; Extraction and Separation Processes
Authors: Özlem Çulcu | Emre Tunçel | Sibel Ilbasmiş-Tamer | Fahriye Figen TIRNAKSIZ
Source: DergiPark (Istanbul University) (article, 2020-10-19)
Field: Materials Science — Polymers and Plastics

Characterization of Thermosensitive Gels for the Sustained Delivery of Dexketoprofen Trometamol for Dermal Applications Biomedical engineering ; Characterization (materials science) ; Chemistry ; Medicine ; Materials science ; Nanotechnology Synthesis and properties of polymers ; Photopolymerization techniques and applications ; Hydrogels: synthesis, properties, applications
Authors: Robert M. Edkins | Markus Appel | Tilo Seydel | Katharina Edkins
Source: Physical Chemistry Chemical Physics (article, 2020-01-01)
Field: Materials Science — Biomaterials

The modifying effect of supramolecular gel fibres on the diffusion of paracetamol and ibuprofen sodium on the picosecond timescale Employing neutron spectroscopy, we follow the tracer diffusion of two non-steroidal anti-inflammatory drug molecules, paracetamol (PCM) and ibuprofen sodium (IBU), in a supramolecular gel and the corresponding bulk solution. Both solutes show altered diffusion behaviour in the gel phase, deviating from each other and their bulk solution. Whilst picosecond diffusion of IBU is slightly quicker in the gel, this effect is significantly increased for PCM, which is up to 70% quicker in the gel than in solution. This effect is independent of changes in the solvent diffusion reported previously. An increased residence time of PCM in solution at lower temperatures points towards the onset of nucleation and crystallisation. This work reports one of the first experiments on the novel Backscattering and Time-of-Flight option (BATS) on the IN16B spectrometer at the Institut Laue-Langevin, France, which with its range and resolution in neutron energy and momentum transfer is ideally suited to observe this type of diffusion. Picosecond ; Diffusion ; Chemistry ; Nucleation ; Quasielastic neutron scattering ; Analytical Chemistry (journal) ; Phase (matter) ; Ibuprofen ; Crystallization ; Neutron scattering ; Chemical physics ; Physical chemistry ; Chromatography ; Inelastic neutron scattering ; Thermodynamics ; Scattering ; Organic chemistry ; Optics Supramolecular Self-Assembly in Materials ; Biochemical effects in animals ; Crystallography and molecular interactions
Authors: Yonhua Tzeng | C. S. Chang
Source: IEEE Open Journal of Nanotechnology (article, 2020-01-01)
Field: Materials Science — Materials Chemistry

Graphene Induced Diamond Nucleation on Tungsten Chemical vapor deposition (CVD) of a diamond film on a non-diamond substrate begins with the insertion of diamond seeds or the formation of diamond nuclei on the substrate. For the deposition of a smooth, large-area and pin-hole free diamond film that adheres well to the substrate, diamond seeds or nuclei need to be of high density, uniformly distributed and adhere well to the substrate. Diamond seeding is not a diamond nucleation process. Bias enhanced nucleation (BEN) is the most effective means of heterogeneous nucleation of diamond for CVD diamond. It is based on a negative biasing voltage between the substrate and the diamond CVD plasma to accelerate positive ions from the plasma to bombard the substrate. Both direct diamond seeding and BEN have technical barriers in practical applications. New diamond nucleation techniques are desired. This paper reports novel heterogenous diamond nucleation along edge line of graphene on tungsten leading to the deposition of continuous diamond films. Based on experimental observation, a diamond nucleation mechanism assisted by sp3 C-W bonds at graphene edge is proposed. It is wished that scientists will become interested in revealing the precise diamond nucleation mechanism. With that, further optimization of this invention may lead to a new, complementary diamond nucleation process for practical deposition of diamond films. Diamond ; Nucleation ; Chemical vapor deposition ; Materials science ; Graphene ; Substrate (aquarium) ; Material properties of diamond ; Nanotechnology ; Chemistry ; Metallurgy ; Geology Diamond and Carbon-based Materials Research ; Graphene research and applications ; Ion-surface interactions and analysis
Authors: Eng Pei Ying | Mohd Zamani Ngali | Mohd Omar Mukhtar Zainul Azmi | Wee Chang An
Source: Journal of Advanced Research in Fluid Mechanics and Thermal Sciences (review, 2020-04-09)
Field: Materials Science — Polymers and Plastics

Drying Droplets: A Review on its Numerical and Experimental Studies to Remove Coffee Ring Effect It is widely known that significant rejection percentage of substrates in the hard disk manufacturing industry is due to the stain appeared during drying of cleaning solution after platting process. Comparison of the characteristics and the causes of these stains suggested that the study of coffee ring effect (CRE) and droplets analysis are needed before any further analysis is carried out. In this review on CRE and droplets, both numerical and experimental works were critically analyzed. Previous studies have highlighted that the drying process of the water droplets are affected by the properties of the water droplets, substrate and temperature. Manipulation of Constant Contact Angle, Constant Contact Radius, advanced contact angle and receding contact angle by varying the arrangement of the substrates and the position of the drying equipment is required to attain the optimum setup to eliminate CRE. Furthermore, manipulation of the temperature of the substrates can enhance the drying process of the droplets before the formation of CRE but the process must not change the properties of the substrates. CRE formation also depends on the properties of the substrates and water droplets. Changing the chemical properties substrates are not advisable to eliminate CRE due to its complex design of the substrates for data storing. All the numerical tests have to be performed according to correct procedures to ensure accurate and acceptance by the industries. Verified and validated results from the evaluation will help to accurately predict the real consequences for further optimization. Knowing that the formation of CRE is caused by the evaporating of the water droplets, we need to find ways to eliminate the formation of water droplets before the heating process, in order to eliminate CRE. Contact angle ; Substrate (aquarium) ; Process (computing) ; Materials science ; RADIUS ; Coffee ring effect ; Process engineering ; Constant (computer programming) ; Mechanical engineering ; Composite material ; Nanotechnology ; Mechanics ; Computer science ; Engineering ; Physics Textile materials and evaluations ; Nanomaterials and Printing Technologies ; Microencapsulation and Drying Processes
Authors: Xia Meng | Shengdan Wang | Wenhua Gao | Wenjia Han | Lucian A. Lucia
Source: BioResources (article, 2020-05-08)
Field: Materials Science — Biomaterials

Thermal pyrolysis characteristics and kinetic analysis of nanofibrillated cellulose/graphene oxide composites The fabrication process determines the microstructure and physical properties of material to some extent. In this study nanofibrillated cellulose /graphene oxide (NFC/GO) composites were fabricated by casting and evaporation methods, respectively. The microstructure and thermostability of the composites were investigated. The composites fabricated by the casting method had more uniform layered microstructure than those made by the evaporation method. The thermogravimetry analysis indicated that in the stage of 100 to 220 °C diffusion, the mechanisms of the Ginstling-Brounstein equation (D4) and the one-way transport equation (D1) can be regarded as the most suitable thermal pyrolysis reaction models for the composites made by the casting method and the evaporation method, respectively. However, in the stage of 220 to 380 °C, the two types of composites showed totally different thermal pyrolysis mechanisms. The results manifested that forming methods could indeed affect the microstructure and thermal degradation process of composites. Materials science ; Microstructure ; Composite material ; Graphene ; Oxide ; Pyrolysis ; Thermogravimetry ; Cellulose ; Casting ; Evaporation ; Chemical engineering ; Metallurgy ; Nanotechnology Advanced Cellulose Research Studies ; Natural Fiber Reinforced Composites ; Flame retardant materials and properties
Authors: Т. В. Тропин | N. Jargalan | М. В. Авдеев | В. Л. Аксенов
Source: Ukrainian Journal of Physics (article, 2020-07-30)
Field: Chemistry — Organic Chemistry

Investigations of the Kinetics of Cluster Growth in Fullerene C60 Solutions Fullerenes tend to form clusters in different solutions. In this work, a brief survey and some results in the field of investigations of the structure and kinetics of clusters growing in C60 solutions are presented. The general character of this phenomenon for fullerenes is emphasized, and the considerations of mechanisms responsible for the formation and growth of clusters are discussed. We distinguish different types of fullerene solvents by the aggregation mechanism. The kinetics of cluster growth measured via the dynamic light scattering is presented. The complicated structure of clusters in different solutions is briefly discussed. Fullerene ; Cluster (spacecraft) ; Kinetics ; Chemical physics ; Materials science ; Nanotechnology ; Chemistry ; Physics ; Computer science ; Organic chemistry Fullerene Chemistry and Applications ; Carbon Nanotubes in Composites ; Graphene research and applications
Authors: Tatsu Kuwatani | Mitsuhiro Toriumi
Source: Earth Planets and Space (article, 2020-02-03)
Field: Chemistry — Inorganic Chemistry

Simple kinetic model for replacement reactions involving solid solutions: the significant role of geofluids Abstract We develop a kinetic model that illustrates the relative role of intergranular diffusion and surface reactions in overall metamorphic net-transfer reactions involving solid solutions. The behavior and state of the system were observed to depend on the non-dimensional parameter(s), defined herein by $$\gamma \equiv (k \cdot L \cdot K^{n-1}) /D^{\mathrm{eff}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>γ</mml:mi><mml:mo>≡</mml:mo><mml:mrow><mml:mo>(</mml:mo><mml:mi>k</mml:mi><mml:mo>·</mml:mo><mml:mi>L</mml:mi><mml:mo>·</mml:mo><mml:msup><mml:mi>K</mml:mi><mml:mrow><mml:mi>n</mml:mi><mml:mo>-</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup><mml:mo>)</mml:mo></mml:mrow><mml:mo>/</mml:mo><mml:msup><mml:mi>D</mml:mi><mml:mi>eff</mml:mi></mml:msup></mml:mrow></mml:math> , where k denotes the dissolution rate constant of the mineral, L denotes the distance between the two minerals participating in the reaction, K denotes the coefficient of the equilibrium abundance ratio of the precipitated component in the intergranular fluid to those in the mineral, n denotes the order of the dissolution reaction, and $$D^{\mathrm{eff}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>D</mml:mi><mml:mi>eff</mml:mi></mml:msup></mml:math> denotes the effective diffusion coefficient of the precipitated component in the intergranular fluid. When $$\gamma$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> is small, the system becomes homogeneous, which is controlled by the surface reaction. In contrast, a large $$\gamma$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>γ</mml:mi></mml:math> implies a heterogeneous system controlled by both surface reaction and diffusion. Geofluid is among the most important influencers of kinetic regimes and reaction textures in metamorphic and metasomatic rocks because the intergranular fluid distribution considerably affects the intergranular diffusivity ( $$D^{\mathrm{eff}}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mi>D</mml:mi><mml:mi>eff</mml:mi></mml:msup></mml:math> ). Our conceptual model can potentially reveal the nature of the reaction kinetics and the fluid–rock interactions and capture the complex behaviors of natural systems in future extensions. Materials science ; Algorithm ; Computer science Radioactive element chemistry and processing ; Groundwater flow and contamination studies ; CO2 Sequestration and Geologic Interactions