jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Tom Fearn | Dolores Pérez‐Marín | Ana Garrido‐Varo | José Emilio Guerrero-Ginel
Source: Chemometrics and Intelligent Laboratory Systems (article, 2019-04-15)
Field: Chemistry — Analytical Chemistry

Classifying with confidence using Bayes rule and kernel density estimation Kernel (algebra) ; Bayes' theorem ; Quadratic classifier ; Linear discriminant analysis ; Kernel density estimation ; Pattern recognition (psychology) ; Mathematics ; Artificial intelligence ; Statistics ; Inference ; Variable kernel density estimation ; Sample (material) ; Computer science ; Kernel method ; Bayesian probability ; Support vector machine Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Advanced Chemical Sensor Technologies
Authors: Mbulisi Sibanda | Onisimo Mutanga | Timothy Dube | John Odindi | Paramu Mafongoya
Source: Agronomy (article, 2019-12-04)
Field: Chemistry — Analytical Chemistry

The Utility of the Upcoming HyspIRI’s Simulated Spectral Settings in Detecting Maize Gray Leafy Spot in Relation to Sentinel-2 MSI, VENµS, and Landsat 8 OLI Sensors Considering the high maize yield loses caused by incidences of disease, as well as incomprehensive monitoring initiatives in crop farming, there is a need for spatially explicit, cost-effective, and consistent approaches for monitoring, as well as for forecasting, food-crop diseases, such as maize Gray Leaf Spot. Such approaches are valuable in reducing the associated economic losses while fostering food security. In this study, we sought to investigate the utility of the forthcoming HyspIRI sensor in detecting disease progression of Maize Gray Leaf Spot infestation in relation to the Sentinel-2 MSI and Landsat 8 OLI spectral configurations simulated using proximally sensed data. Healthy, intermediate, and severe categories of maize crop infections by the Gray Leaf Spot disease were discriminated based on partial least squares–discriminant analysis (PLS-DA) algorithm. Comparatively, the results show that the HyspIRI’s simulated spectral settings slightly performed better than those of Sentinel-2 MSI, VENµS, and Landsat 8 OLI sensor. HyspIRI exhibited an overall accuracy of 0.98 compared to 0.95, 0.93, and 0.89, which were exhibited by Sentinel-2 MSI, VENµS, and Landsat 8 OLI sensor sensors, respectively. Furthermore, the results showed that the visible section, red-edge, and NIR covered by all the four sensors were the most influential spectral regions for discriminating different Maize Gray Leaf Spot infections. These findings underscore the potential value of the upcoming hyperspectral HyspIRI sensor in precision agriculture and forecasting of crop-disease epidemics, which are necessary to ensure food security. Hyperspectral imaging ; Partial least squares regression ; Crop ; Red edge ; Spectral signature ; Environmental science ; Remote sensing ; Agronomy ; Computer science ; Biology ; Mathematics ; Artificial intelligence ; Statistics ; Geography Spectroscopy and Chemometric Analyses ; Remote Sensing in Agriculture ; Smart Agriculture and AI
Authors: Vladimir Mironov | Yuri Alexeev | Dmitri G. Fedorov
Source: International Journal of Quantum Chemistry (article, 2019-04-26)
Field: Chemistry — Spectroscopy

Multithreaded parallelization of the energy and analytic gradient in the fragment molecular orbital method Abstract The fragment molecular orbital method in GAMESS is parallelized in a multithreaded OpenMP implementation combined with the MPI version of the two‐level generalized distributed data interface. The energy and analytic gradient in gas phase and the polarizable continuum model of solvation are parallelized in this hybrid three‐level scheme, achieving a large memory footprint reduction and a high parallel efficiency on Intel Xeon Phi processors. The parallel efficiency is demonstrated on the Stampede2 and Theta supercomputers using up to 2048 nodes (262 144 threads). Parallel computing ; Xeon ; Computer science ; Xeon Phi ; Fragment molecular orbital ; Solvation ; Computational science ; Molecular orbital ; Chemistry ; Molecule Advanced NMR Techniques and Applications ; Advanced Chemical Physics Studies ; Spectroscopy and Quantum Chemical Studies
Authors: Abir Abdessalem | S. Tamboura | Joseph Fitoussi | Hachmi Ben Daly | Abbas Tcharkhtchi
Source: Journal of Applied Polymer Science (article, 2019-08-15)
Field: Materials Science — Polymers and Plastics

Bi‐phasic water diffusion in sheet molding compound composite ABSTRACT Sheet molding compound (SMC) composite has been studied under humid‐aging conditions. Diffusion of water within the material, as measured by gravimetry, was found to be in good agreement with the “Langmuir‐type” diffusion model developed by Carter and Kibler. In their theory, Carter and Kibler consider the existence of two types of water molecules in the material, «mobile» and «bound». In this study, these two types have been considered separately. Furthermore, Infrared spectroscopy (FTIR) analysis has been performed by decomposition of signals to study the fraction of free (mobile) and hydrogen‐bounded water. Thermal analysis and microscopic observations were put forward to explain the two types of water molecules. In this contribution, we found a “bi‐phasic” water diffusion. We suggest that the «mobile» water corresponding to the diffusion in the micro‐porosities follows a Fickien kinetic, which turns to sigmoidal one at a specific time of immersion τ. Whereas the kinetic of «bound» water, referring to crosslinking and plasticization, follows a sigmoidal kinetic, which turns to Fickien behavior when the overall network is saturated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48381. Bound water ; Diffusion ; Kinetic energy ; Fourier transform infrared spectroscopy ; Materials science ; Composite number ; Composite material ; Sheet moulding compound ; Molecule ; Chemistry ; Polymer chemistry ; Thermodynamics ; Chemical engineering ; Physics ; Organic chemistry Natural Fiber Reinforced Composites ; Polymer crystallization and properties ; Lignin and Wood Chemistry
Authors: Francis Oluwadayo Asokogene | Muhammad Abbas Ahmad Zaini | Muhammad Misau Idris | Surajudeen Abdulsalam | El-Nafaty Aliyu Usman
Source: International Journal of Chemical Reactor Engineering (article, 2019-10-30)
Field: Materials Science — Materials Chemistry

Methylene Blue Adsorption onto Neem Leave/Chitosan Aggregates: Isotherm, Kinetics and Thermodynamics Studies Abstract The work was aimed at evaluating the adsorptive properties of neem leave/chitosan aggregates for methylene blue removal. The adsorbent was screened to form coarse (CCANL, 600 µm), medium (MCANL, 300 µm) and fine (FCANL, 150 µm) neem leave/chitosan particles. The samples were characterized for pH, water binding capacity (WBC), surface chemistry by Fourier transform infrared spectroscopy, surface morphology by scanning electron microscope and textural properties by Brunauer-Emmett-Teller method. CCANL, MCANL and FCANL possessed specific surface area of 255, 258 and 242 m 2 /g, respectively. The effects of initial concentration, adsorbent dosage, contact time, pH and temperature were studied. CCANL, MCANL and FCANL demonstrated adsorption capacity of 102, 92.5 and 105 mg/g, respectively, in which ionic interaction and mesopore filling were the possible adsorption mechanisms. The equilibrium data were well fitted by Redlich-Peterson model, suggesting a monolayer adsorption onto a heterogeneous surface of adsorbent. The kinetics data were best described by pseudo-second-order and intraparticle diffusion models, for which the film diffusion, intraparticle diffusion and surface adsorption could co-exist as the controlling steps in adsorption. Adsorption of methylene blue onto chitosan composites was spontaneous, endothermic and demonstrated increased randomness at solid-solution interface. Adsorption ; Endothermic process ; Methylene blue ; Chemistry ; Chemical engineering ; Diffusion ; Chitosan ; Kinetics ; Langmuir adsorption model ; Fourier transform infrared spectroscopy ; Mesoporous material ; Materials science ; Organic chemistry ; Thermodynamics ; Catalysis Pickering emulsions and particle stabilization ; Adsorption and biosorption for pollutant removal ; Surfactants and Colloidal Systems
Authors: Fang‐Yuan Zhang | Mei Hong | Zhi Liu | Haiyang Yu | Chuanyu Qin | Bing‐Bing Liu | Yangxue Li
Source: ChemistrySelect (article, 2019-11-22)
Field: Materials Science — Materials Chemistry

Facile Room‐Temperature Synthesis of Novel Porous Three‐Component Hybrid Covalent Organic Polymers and Their Applications towards Sulfadiazine Adsorption Abstract Since the environmental pollution posed by widely used sulfonamide antibiotics has been reported in natural aquatic system, designing novel adsorbents with excellent behaviors for adsorptive removal of sulfonamide antibiotics becomes a critical challenge in remediation management. Herein, two three‐component hybrid covalent organic polymers were successfully developed through a facile room‐temperature solution‐suspension method based on dynamic covalent Schiff‐base chemistry and used to remove a typical sulfonamide antibiotic [sulfadiazine (SDZ)] from aqueous solution. The 1,3,5‐triformylphloroglucinol (TFP) and benzene‐1,3,5‐tricarbohydrazide (BTCH) reacted with benzidine (BD) (JLUE‐COP‐26) and exhibited a good adsorption capacity for SDZ, followed by the reaction of TFP, BTCH and p ‐phenylenediamine (PDA) (JLUE‐COP‐25). Moreover, the adsorption data of SDZ by two JLUE‐COPs were analyzed to be pseudo‐second‐order kinetic representable and Langmuir adsorption model fitted. In addition, the possible underlying mechanisms were proposed as a combination of porous feature, electrostatic force, hydrophobic interaction, π‐π stacking and hydrogen bonding interaction. Sulfonamide ; Sulfadiazine ; Adsorption ; Chemistry ; Chemical engineering ; Covalent organic framework ; Polymer ; Covalent bond ; Aqueous solution ; Organic chemistry ; Antibiotics Covalent Organic Framework Applications ; Metal-Organic Frameworks: Synthesis and Applications ; Advanced Photocatalysis Techniques
Authors: Abdalhadi Deghles | Othman Hamed | M Tarlani Azar | Bahia Abu Lail | Khalil Azzaoui | Ahmad Abu Obied | Shehdeh Jodeh
Source: BioResources (article, 2019-06-19)
Field: Materials Science — Biomaterials

Cellulose with bidentate chelating functionality: An adsorbent for metal ions from wastewater A cellulose derivative with multiple coordination sites for metals composed of cellulose powder and 1,2-pheneylnediamine was synthesized and evaluated as an adsorbent for metal ions from wastewater. The cellulose powder was generated from the solid waste of the olive industry. The adsorption efficiency of the cellulose amine polymer toward Fe(III) and Pb(II) was investigated as a function of adsorbent dose, temperature, pH, and time. The adsorption parameters that lead to excellent adsorption efficiency were determined. In addition, the polymer showed an excellent extraction efficiency toward approximately 20 metal ions present in a sewage sample. The cellulose amine derivative had several coordination sites that included amine, hydroxyl, and aromatic groups. The diversity and frequency of the coordination sites explained the high efficiency of the polymer for metal ions. The thermodynamic analysis results supported the spontaneous adsorption efficiency of the polymer at room temperature. The adsorption process fit well with the Langmuir adsorption isotherm model. Adsorption ; Cellulose ; Metal ions in aqueous solution ; Amine gas treating ; Polymer ; Langmuir adsorption model ; Materials science ; Chelation ; Inorganic chemistry ; Metal ; Industrial wastewater treatment ; Wastewater ; Chemical engineering ; Chemistry ; Organic chemistry ; Waste management ; Metallurgy Advanced Cellulose Research Studies ; Adsorption and biosorption for pollutant removal ; Recycling and Waste Management Techniques
Authors: Chai Yin | Chao Xu | Wenhao Yu | Yu‐Xiang Jia | Weizhi Sun | Guizhong Zhou | Mo Xian
Source: RSC Advances (article, 2019-01-01)
Field: Chemistry — Analytical Chemistry

Synthesis of a novel isatin and ethylenediamine modified resin and effective adsorption behavior towards Orange G In this study, a novel crosslinked resin 135-I-EDA modified by isatin and ethylenediamine was synthesized through two continuous functionalization steps using chloromethylated styrene-divinylbenzene copolymer as the substrate. In the first step, the cross-linking reaction and isatin incorporation were realized in a creative one-pot reaction using Friedel-crafts reaction in the presence of isatin to give resin 135-I; in the second step, ethylenediamine was successfully introduced on the carbonyl of the modified isatin to further increase the chemically interacting sites. The double-modified resin 135-I-EDA displayed the best adsorption performance (113.38 mg g<sup>-1</sup>) towards Orange G, which is 1.99 times and 3.49 times as much as that of 135-I (56.94 mg g<sup>-1</sup>) and commercial resin H-103 (32.51 mg g<sup>-1</sup>) respectively. This is attributed to its superior porous structure formed in the Friedel-crafts reaction and multiple modified groups in isatin and ethylenediamine. π-π conjugation and hydrogen bonding are the main driving forces for the adsorption. The pseudo-second-order rate equation characterizes the adsorption kinetic curves well and 135-I-EDA displayed the fastest adsorption rate. The study also proved that the 135-I-EDA has a better adsorption capacity for OG in more acidic solution, at higher temperature and higher salinity, which provides a basis for the treatment of industrial dye wastewater. Isatin ; Ethylenediamine ; Adsorption ; Chemistry ; Orange (colour) ; Nuclear chemistry ; Combinatorial chemistry ; Organic chemistry ; Food science Dye analysis and toxicity ; Dyeing and Modifying Textile Fibers
Authors: Katarzyna Merkel | Chris Welch | Z. Ahmed | Wiktor Piecek | Georg H. Mehl
Source: The Journal of Chemical Physics (article, 2019-09-20)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Dielectric response of electric-field distortions of the twist-bend nematic phase for LC dimers Wide band dielectric spectroscopy of bent-shaped achiral liquid-crystal dimers 1″-n″-bis(4-cyanobiphenyl-4'-yl) n-alkanes (CBnCB n = 7, 9, 11) has been investigated in a frequency range 0.1 Hz-100 MHz using planar-aligned cells of sample thicknesses ranging from 2 to 10 (μm) over a temperature range that covers both nematic and twist bend nematic phases. Two peaks in the dielectric spectrum in the higher frequency range are assigned to the molecular relaxation processes. The peak at the highest frequency, ∼40 to 80 MHz, is assigned to an internal precessional rotation of a single unit of the dimer around the director. The mode in the next lower frequency range of 2-10 MHz is assigned to the spinning rotation of the dimer around its long axis. This involves fluctuations of the dipole moment of the bent-shaped conformation that is directed along its arrow direction of the bow shape formed by the dimer. The peak in the frequency range 100 kHz-1 MHz can be assigned to the collective fluctuations of the local director with reference to the helical axis of the N<sub>TB</sub> structure. The dependence of its frequency on temperature is reminiscent of the soft mode observed at the SmA<sup>*</sup> to SmC<sup>*</sup> phase transition. This result clearly corresponds to the electro-clinic effect-the response of the director to the applied electric field in an electro-optic experiment. The lowest frequency mode, observed in the frequency range of 0.1 Hz-100 Hz, is identified with the Goldstone mode. This mode is concerned with the long range azimuthal angle fluctuations of the local director. This leads to an alternating compression and expansion of the periodic structure of the N<sub>TB</sub> phase. Liquid crystal ; Dipole ; Electric field ; Phase (matter) ; Dielectric ; Bent molecular geometry ; Relaxation (psychology) ; Materials science ; Condensed matter physics ; Molecular physics ; Optics ; Nuclear magnetic resonance ; Chemistry ; Physics ; Optoelectronics Liquid Crystal Research Advancements ; Molecular spectroscopy and chirality ; Surfactants and Colloidal Systems
Authors: Piotr Polanowski | Andrzej Sikorski
Source: Journal of Molecular Modeling (article, 2019-03-01)
Field: Materials Science — Materials Chemistry

Motion in a crowded environment: the influence of obstacles’ size and shape and model of transport Simulations of motion in a complex crowded environment were performed. We employed the dynamic lattice liquid model, which was based on the cooperative movement concept. This algorithm is capable of working at very high densities, and the motion of all objects was highly correlated. The so-called motion of a single agent, where the motion of molecules is considered as a random walk without any correlation with other moving objects, was also calculated as the state of reference. Immobilized chains embedded in a two-dimensional triangular lattice modeled the crowded environment. The dynamic behavior of movable objects was studied and the influence of the structure of the matrix of obstacles on the molecular transport was discussed. It was shown that the type of transport has an impact on the dynamics of the system. The appearance and properties of subdiffusive motion were analyzed and referred to the structure of polymer systems. Motion (physics) ; Random walk ; Lattice (music) ; Hexagonal lattice ; Statistical physics ; Movement (music) ; Biological system ; Collective motion ; Dynamics (music) ; Matrix (chemical analysis) ; Classical mechanics ; Computer science ; Physics ; Chemical physics ; Materials science ; Mathematics ; Condensed matter physics ; Acoustics Material Dynamics and Properties ; Lipid Membrane Structure and Behavior ; Theoretical and Computational Physics
Authors: Naveed Anjum | B. Suresha | Somanahally Lingaiah Ajit Prasad
Source: Open Journal of Composite Materials (article, 2019-01-01)
Field: Materials Science — Polymers and Plastics

Influence of Water Ageing on Mechanical Properties of CaCO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; Filler Filled Epoxy Resin and &amp;lt;em&amp;gt;Sansevieria&amp;lt;/em&amp;gt;/Carbon Fiber Reinforced Composites The present paper studies water absorption behavior and its consequence on mechanical properties of untreated and chemically treated Sansevieria /carbon fiber reinforced hybrid epoxy (Sria/CF-Ep) composite with calcium carbonate (CaCO3) nanoparticles. Sansevieria /carbon fiber (30/5 wt%) reinforced hybrid epoxy composite with 1.5, 3 and 4.5 wt% of CaCO3 have been developed by hand lay-up method followed by heat press. The water absorption characteristics of the Sria fibers were obtained by immersing the composite samples in sea water at room temperature, until reaching their water content saturation level. The dry and water-immersed hybrid composite samples were subjected to hardness, interlaminar shear, tensile, flexural, and impact tests. The water absorption development of hybrid composites was found to follow Fickian diffusion behavior. Diffusion coefficients and maximum water uptake results were evaluated; the outcome showed that both increased with an increase in filler loading to study the consequence of water penetration in the fiber/matrix interface. The study shows that the mechanical and water-resistant properties of the Sria were improved through chemical treatment and hybridization. Nevertheless, as a result of water penetrating the fiber/matrix interface, longer water-immersion times reduced the tensile and flexural strength of the composites. Materials science ; Composite material ; Absorption of water ; Flexural strength ; Epoxy ; Ultimate tensile strength ; Composite number ; Penetration (warfare) ; Fiber ; Calcium carbonate Natural Fiber Reinforced Composites ; Tribology and Wear Analysis ; Polymer Nanocomposites and Properties
Authors: Ali Osman Erdoğdular | Dilek Kılıç Apar
Source: Applied Biological Chemistry (article, 2019-04-11)
Field: Chemistry — Analytical Chemistry

Bioremoval of reactive dye Remazol Navy by kefir grains Potential use of living and non-living kefir grains (small, gelatinous white/yellow irregularly shaped masses consist of live bacteria and yeasts) on removal of reactive dye Remazol Navy RGB from aqueous solutions were investigated. Experiments were carried out under different process conditions in order to optimize and model the bioremoval processes. At all conditions the living kefir grains exhibited higher dye removal efficiencies than the non-living grains. In 180 min, 96.3% and 79.4% dye removal was obtained with living and non-leaving kefir grains respectively, at pH 2, 25 °C for 100 mg/L initial dye concentration by using 2.4 g/L kefir grain. Maximum adsorption capacities by living and inactivated kefir grains were obtained at 400 mg/L initial dye concentration as 134.59 and 56.92 mg/g respectively. Consecutive batch studies show that the living kefir grains could be reused over at least 5 cycles with high dye removal efficiency without any nutrition supplement. The biosorption kinetics both for living and non-living kefir grains were best described with pseudo-first-order kinetic model. On the other hand the biosorption equilibrium for living and non-living kefir grains were better defined by Temkin and Langmuir isotherm models respectively. Results suggest that the kefir grains could be used efficiently, eco-friendly and economically for removal of dyes from aqueous solutions. Chemistry ; Kefir ; Biosorption ; Aqueous solution ; Reactive dye ; Adsorption ; Nuclear chemistry ; Kinetics ; Food science ; Organic chemistry ; Bacteria ; Biology ; Dyeing Dye analysis and toxicity ; Adsorption and biosorption for pollutant removal ; Enzyme-mediated dye degradation
Authors: Tim Almqvist | David O. Winge | Emmanuel Dupont | Andreas Wacker
Source: The European Physical Journal B (article, 2019-04-01)
Field: Chemistry — Spectroscopy

Domain formation and self-sustained oscillations in quantum cascade lasers We study oscillations in quantum cascade lasers due to traveling electric field domains, which are observed both in simulations and experiments. These oscillations occur in a range of negative differential resistance and we clarify the condition determining whether the boundary between domains of different electric field can become stationary. Cascade ; Quantum ; Laser ; Electric field ; Field (mathematics) ; Domain (mathematical analysis) ; Range (aeronautics) ; Semiconductor laser theory Spectroscopy and Laser Applications ; Semiconductor Lasers and Optical Devices ; Nonlinear Dynamics and Pattern Formation