jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ciro Aprea | Adriana Greco | Angelo Maiorino | Claudia Masselli
Source: Energies (article, 2019-07-28)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Enhancing the Heat Transfer in an Active Barocaloric Cooling System Using Ethylene-Glycol Based Nanofluids as Secondary Medium Barocaloric cooling is classified as environmentally friendly because of the employment of solid-state materials as refrigerants. The reference and well-established processes are based on the active barocaloric regenerative refrigeration cycle, where the solid-state material acts both as refrigerant and regenerator; an auxiliary fluid (generally water of water/glycol mixtures) is used to transfer the heat fluxes with the final purpose of subtracting heat from the cold heat exchanger coupled with the cold cell. In this paper, we numerically investigate the effect on heat transfer of working with nanofluids as auxiliary fluids in an active barocaloric refrigerator operating with a vulcanizing rubber. The results reveal that, as a general trend, adding 10% of copper nanoparticles in the water/ethylene-glycol mixture carries to +30% as medium heat transfer enhancement. Nanofluid ; Refrigerant ; Ethylene glycol ; Refrigeration ; Materials science ; Heat transfer ; Heat transfer enhancement ; Thermodynamics ; Heat exchanger ; Refrigerator car ; Chemical engineering ; Heat transfer coefficient ; Engineering Magnetic and transport properties of perovskites and related materials ; Ferroelectric and Piezoelectric Materials ; Shape Memory Alloy Transformations
Authors: Federico Stilo | Chiara Cordero | Barbara Sgorbini | Carlo Bicchi | Erica Liberto
Source: Separations (article, 2019-07-15)
Field: Chemistry — Spectroscopy

Highly Informative Fingerprinting of Extra-Virgin Olive Oil Volatiles: The Role of High Concentration-Capacity Sampling in Combination with Comprehensive Two-Dimensional Gas Chromatography The study explores the complex volatile fraction of extra-virgin olive oil by combining high concentration-capacity headspace approaches with comprehensive two-dimensional gas chromatography, which is coupled with time of flight mass spectrometry. The static headspace techniques in this study are: (a) Solid-phase microextraction, with multi-polymer coating (SPME- Divinylbenzene/Carboxen/Polydimethylsiloxane), which is taken as the reference technique; (b) headspace sorptive extraction (HSSE) with either a single-material coating (polydimethylsiloxane—PDMS) or a dual-phase coating that combines PDMS/Carbopack and PDMS/EG (ethyleneglycol); (c) monolithic material sorptive extraction (MMSE), using octa-decyl silica combined with graphite carbon (ODS/CB); and dynamic headspace (d) with either PDMS foam, operating in partition mode, or Tenax TA™, operating in adsorption mode. The coverage of both targeted and untargeted 2D-peak-region features, which corresponds to detectable analytes, was examined, while concentration factors (CF) for a selection of informative analytes, including key-odorants and off-odors, and homolog-series relative ratios were calculated and the information capacity was discussed. The results highlighted the differences in concentration capacities, which were mainly caused by polymer-accumulation characteristics (sorptive/adsorptive materials) and its amount. The relative concentration capacity for homologues and potent odorants was also discussed, while headspace linearity and the relative distribution of analytes, as a function of different sampling amounts, was examined. This last point is of particular interest in quantitative studies where accurate data is needed to derive consistent conclusions. Polydimethylsiloxane ; Chromatography ; Tenax ; Divinylbenzene ; Chemistry ; Solid-phase microextraction ; Coating ; Adsorption ; Analyte ; Mass spectrometry ; Extraction (chemistry) ; Gas chromatography ; Polymer ; Partition coefficient ; Analytical Chemistry (journal) ; Gas chromatography–mass spectrometry ; Styrene ; Copolymer ; Organic chemistry Analytical Chemistry and Chromatography ; Advanced Chemical Sensor Technologies ; Analytical chemistry methods development
Authors: Xiao Xu | Lijuan Xie | Yibin Ying
Source: Frontiers of Agricultural Science and Engineering (review, 2019-01-01)
Field: Chemistry — Analytical Chemistry

Factors influencing near infrared spectroscopy analysis of agro-products: a review The near infrared (NIR) spectroscopy technique has wide applications in agriculture with the advantages of being nondestructive, sensitive, safe and rapid. However, there are still more than 40 error sources influencing the robustness and accuracy of its calibration and operation. Environmental, sample and instrument factors that influence the analysis are discussed in this review, including temperature, humidity and other factors that introduce uncertainty. Error sources from livestock products, fruit and vegetables, which are the most common objects in the field of NIR analysis, are also emphasized in the second part. In addition, studies utilizing different instruments, spectral pretreatments, variable selection methods, wavelength ranges, detection modes and calibration methods are tabulated to illustrate the complications they introduce and how they influence NIR analysis. It is suggested that large scale of data with abundant varieties can be used to build a more robust calibration model, in order to improve the robustness and accuracy of the NIR analytical model, and overcome problems caused by confining analysis to too many uniform samples. Robustness (evolution) ; Near-infrared spectroscopy ; Calibration ; Environmental science ; Remote sensing ; Computer science ; Spectroscopy ; Biological system ; Infrared ; Process engineering ; Biochemical engineering ; Statistics ; Mathematics ; Optics ; Engineering ; Chemistry ; Physics ; Geography Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Meat and Animal Product Quality
Authors: Aleksandra Lelević | Vincent Souchon | Maxime Moreaud | Chantal Lorentz | C. Geantet
Source: Journal of Separation Science (review, 2019-11-21)
Field: Chemistry — Spectroscopy

Gas chromatography vacuum ultraviolet spectroscopy: A review Accelerated technological progress and increased complexity of interrogated matrices imposes a demand for fast, powerful, and resolutive analysis techniques. Gas chromatography has been for a long time a 'go-to' technique for the analysis of mixtures of volatile and semi-volatile compounds. Coupling of the several dimensions of gas chromatography separation has allowed to access a realm of improved separations in the terms of increased separation power and detection sensitivity. Especially comprehensive separations offer an insight into detailed sample composition for complex samples. Combining these advanced separation techniques with an informative detection system such as vacuum ultraviolet spectroscopy is therefore of great interest. Almost all molecules absorb the vacuum ultraviolet radiation and have distinct spectral features with compound classes exhibiting spectral signature similarities. Spectral information can be 'filtered' to extract the response in the most informative spectral ranges. Developed algorithms allow spectral mixture estimation of coeluting species. Vacuum ultraviolet detector follows Beer-Lambert law, with the possibility of calibrationless quantitation. The purpose of this article is to provide an overview of the features and specificities of gas chromatography-vacuum ultraviolet spectroscopy coupling which has gained interest since the recent introduction of a commercial vacuum ultraviolet detector. Potentials and limitations, relevant theoretical considerations, recent advances and applications are explored. Ultraviolet ; Vacuum ultraviolet ; Gas chromatography ; Detector ; Chemistry ; Spectroscopy ; Analytical Chemistry (journal) ; Chromatography ; Materials science ; Optoelectronics ; Optics ; Physics Analytical Chemistry and Chromatography ; Advanced Chemical Sensor Technologies ; Mass Spectrometry Techniques and Applications
Authors: Andries J. Daniels | Carlos Poblete-Echeverría | Umezuruike Linus Opara | H.H. Nieuwoudt
Source: Frontiers in Plant Science (article, 2019-11-28)
Field: Chemistry — Analytical Chemistry

Measuring Internal Maturity Parameters Contactless on Intact Table Grape Bunches Using NIR Spectroscopy The determination of internal maturity parameters of table grape is usually done destructively using manual methods that are time-consuming. The possibility was investigated to determine whether key fruit attributes, namely, total soluble solids (TSS); titratable acidity (TA), TSS/TA, pH, and BrimA (TSS - <i>k</i> x TA) could be determined on intact table grape bunches using Fourier transform near-infrared (FT-NIR) spectroscopy and a contactless measurement mode. Partial Least Squares (PLS) regression models were developed for the maturity and sensory quality parameters using grapes obtained from two consecutive harvest seasons. Statistical indicators used to evaluate the models were the number of latent variables (LVs) used to build the model, the prediction correlation coefficient (R<sup>2</sup>p) and root mean square error of prediction (RMSEP). For the respective parameters TSS, TA, TSS/TA, pH, and BrimA, the LVs were 21, 23, 5, 7, and 24, the R<sup>2</sup>p = 0.71, 0.33, 0.57, 0.28, and 0.77, and the RMSEP = 1.52, 1.09, 7.83, 0.14, and 1.80. TSS performed best when moving smoothing windows (MSW) + multiplicative scatter correction (MSC) was used as spectral pre-processing technique, TA with standard normal variate (SNV), TSS/TA with Savitzky-Golay first derivative (SG1d), pH with SG1d, and BrimA with MSC. This study provides the first steps towards a completely nondestructive and contactless determination of internal maturity parameters of intact table grape bunches. Partial least squares regression ; Coefficient of determination ; Bunches ; Mathematics ; Titratable acid ; Standard deviation ; Correlation coefficient ; Linear regression ; Analytical Chemistry (journal) ; Standard error ; Chemistry ; Statistics ; Optics ; Chromatography ; Food science ; Physics Spectroscopy and Chemometric Analyses ; Horticultural and Viticultural Research ; Fermentation and Sensory Analysis
Authors: Yue Zhang | Hongzhe Jiang | Wei Wang
Source: Applied Sciences (article, 2019-09-19)
Field: Chemistry — Analytical Chemistry

Feasibility of the Detection of Carrageenan Adulteration in Chicken Meat Using Visible/Near-Infrared (Vis/NIR) Hyperspectral Imaging The detection of carrageenan adulteration in chicken meat using a hyperspectral imaging (HSI) technique associated with three spectroscopic transforms was investigated. Minced chicken was adulterated with carrageenan solution (2% w/v) in the volume range of 0–5 mL at an increment of 1 mL. Hyperspectral images of prepared samples were captured in a reflectance mode in a Visible/Near-Infrared (Vis/NIR, 400–1000 nm) region. The reflectance (R) spectra were first extracted from regions of interest (ROIs) by applying a mask that was built using band math combined with thresholding and were then transformed into two other spectral units, absorbance (A) and Kubelka-Munck (KM). Partial least squares regression (PLSR) models based on full raw and preprocessed spectra in the three profiles were established and A spectra were found to perform best with Rp2 = 0.92, root mean square error of prediction set (RMSEP) = 0.48, and residual predictive deviation (RPD) = 6.18. To simplify the models, several wavelengths were selected using regression coefficients (RC) based on all three spectral units, and 10 wavelengths selected from A spectra (409, 425, 444, 521, 582, 621, 763, 840, 893, and 939 nm) still performed best with the Rp2, RMSEP, and RPD of 0.85, 0.93, and 3.20, respectively. Thus, the preferred simplified RC-A-PLSR model was selected and transferred into each pixel to obtain the distribution maps and finally, the general different adulteration levels of different samples were readily discernible. The overall results ascertained that the HSI technique demonstrated to be an effective tool for detecting and visualizing carrageenan adulteration in authentic chicken meat, especially in the absorbance mode. Hyperspectral imaging ; Partial least squares regression ; Absorbance ; Mathematics ; Near-infrared spectroscopy ; Mean squared error ; Analytical Chemistry (journal) ; Chemistry ; Artificial intelligence ; Chromatography ; Computer science ; Optics ; Statistics ; Physics Spectroscopy and Chemometric Analyses ; Identification and Quantification in Food ; Advanced Chemical Sensor Technologies
Authors: Samira Salehi | Mansoor Anbia
Source: Cellulose (article, 2019-05-04)
Field: Chemistry — Inorganic Chemistry

Performance comparison of chitosan–clinoptilolite nanocomposites as adsorbents for vanadium in aqueous media Vanadium ; Adsorption ; Freundlich equation ; Materials science ; Aqueous solution ; Desorption ; Clinoptilolite ; Langmuir ; Metal ions in aqueous solution ; Ionic strength ; Inorganic chemistry ; Chemical engineering ; Chemistry ; Metal ; Zeolite ; Organic chemistry ; Metallurgy ; Catalysis Vanadium and Halogenation Chemistry ; Corrosion Behavior and Inhibition ; Fluoride Effects and Removal
Authors: Roger Borges | Fernando Wypych | Élodie Petit | Claude Forano | Vanessa Prévot
Source: Nanomaterials (article, 2019-02-01)
Field: Materials Science — Materials Chemistry

Potential Sustainable Slow-Release Fertilizers Obtained by Mechanochemical Activation of MgAl and MgFe Layered Double Hydroxides and K2HPO4 This study describes the behavior of potential slow-release fertilizers (SRF), prepared by the mechanochemical activation of calcined Mg₂Al-CO₃ or Mg₂Fe-CO₃ layered double hydroxides (LDH) mixed with dipotassium hydrogen phosphate (K₂HPO₄). The effects of LDH thermal treatment on P/K release behavior were investigated. Characterizations of the inorganic composites before and after release experiments combined X-Ray diffraction (XRD), Fourier-transform infra-red spectroscopy (FTIR), solid-state nuclear magnetic resonance (NMR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The best release profile (<75% in 28 days and at least 75% release) was obtained for MgAl/K₂HPO₄ (9 h milling, 2:1 molar ratio, MR). Compared to readily used K₂HPO₄, milling orthophosphate into LDH matrices decreases its solubility and slows down its release, with 60% and 5.4% release after 168 h for MgAl/K₂HPO₄ and MgFe/K₂HPO₄ composites, respectively. Mechanochemical addition of carboxymethylcellulose to the LDH/K₂HPO₄ composites leads to a noticeable improvement of P release properties. Layered double hydroxides ; Fourier transform infrared spectroscopy ; Scanning electron microscope ; Calcination ; Nuclear chemistry ; Materials science ; Solubility ; Phosphate ; Chemical engineering ; Chemistry ; Inorganic chemistry ; Catalysis ; Hydroxide ; Organic chemistry ; Composite material Layered Double Hydroxides Synthesis and Applications ; Polymer-Based Agricultural Enhancements ; Clay minerals and soil interactions
Authors: Shao‐Chuan Li | Li‐Xuan Cai | Li‐Peng Zhou | Fang Guo | Qing‐Fu Sun
Source: Science China Chemistry (article, 2019-03-12)
Field: Chemistry — Organic Chemistry

Supramolecular synthesis of coumarin derivatives catalyzed by a coordination-assembled cage in aqueous solution Supramolecular chemistry ; Salicylaldehyde ; Chemistry ; Catalysis ; Aqueous solution ; Malononitrile ; Supramolecular catalysis ; Combinatorial chemistry ; Reaction mechanism ; Photochemistry ; Polymer chemistry ; Organic chemistry ; Crystal structure ; Schiff base Supramolecular Chemistry and Complexes ; Metal-Organic Frameworks: Synthesis and Applications ; Magnetism in coordination complexes
Authors: Jorge Torres-Rodríguez | József Kalmár | Melita Menelaou | Ladislav Čelko | Karel Dvořák | Jaroslav Cihlář | Jozef Kaiser | Enikö Győri | Péter Veres | István Fábián | István Lázár
Source: The Journal of Supercritical Fluids (article, 2019-02-27)
Field: Chemistry — Spectroscopy

Heat treatment induced phase transformations in zirconia and yttria-stabilized zirconia monolithic aerogels Materials science ; Cubic zirconia ; Calcination ; Crystallite ; Yttria-stabilized zirconia ; Aerogel ; Chemical engineering ; Tetragonal crystal system ; Supercritical fluid ; Supercritical drying ; Phase (matter) ; Amorphous solid ; Monoclinic crystal system ; Composite material ; Ceramic ; Crystallography ; Crystal structure ; Catalysis ; Metallurgy ; Chemistry ; Organic chemistry Aerogels and thermal insulation ; Catalytic Processes in Materials Science ; Catalysis and Oxidation Reactions
Authors: Zexin Yu | Hatem Moussa | Meimei Liu | Raphaël Schneider | Michel Molière | Hanlin Liao
Source: Surface and Coatings Technology (article, 2019-07-30)
Field: Materials Science — Materials Chemistry

Heterostructured metal oxides-ZnO nanorods films prepared by SPPS route for photodegradation applications Nanorod ; Materials science ; Photocatalysis ; Photodegradation ; Methyl orange ; Heterojunction ; Raman spectroscopy ; Chemical engineering ; Visible spectrum ; Metal ; Nanotechnology ; Optoelectronics ; Catalysis ; Optics ; Chemistry ; Metallurgy ZnO doping and properties ; Copper-based nanomaterials and applications ; Advanced Photocatalysis Techniques
Authors: Sandeep Kumar | Kapil Bhatt | Pramod Kumar | Sandeep Sharma | Amit Kumar | C. C. Tripathi
Source: RSC Advances (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Laser patterned, high-power graphene paper resistor with dual temperature coefficient of resistance Printing of electronic devices on a paper substrate using 2D graphene-based ink is an opening gate to innovative applications, where devices would be biodegradable, eco-friendly and can be disposed of with negligible impact on the environment. A resistor is a key element of electronic devices and their application area depends upon its power rating and temperature coefficient of resistance (TCR). In this work, in house developed graphene ink is successfully utilized to fabricate a paper-based resistor using a bar coating technique. Dimensional patterning with precise known values of resistance is achieved using a laser with freedom of shape and size which has been explored for the first time on a paper substrate. The resistor has potential to handle ∼7 W power at room temperature with capacity to withstand up to 200 V which is the highest among reported printed resistors. A dual, low and high TCR is observed, correspondingly in cold (173 K to 300 K) and hot (300 K to 373 K) temperature regions with an activation energy <i>E</i> <sub>a</sub> of ∼8 meV for the cold region which is 375 percent lower than the hot region (∼30 meV). The dual TCR behaviour is of great importance for application as a stable resistor up to room temperature, and as a thermistor above room temperature. Resistor ; Graphene ; Dual (grammatical number) ; Temperature coefficient ; Materials science ; Power (physics) ; Optoelectronics ; Laser ; Nanotechnology ; Electrical engineering ; Composite material ; Physics ; Thermodynamics ; Optics ; Engineering ; Art Graphene research and applications ; Advanced Sensor and Energy Harvesting Materials ; Advanced Memory and Neural Computing
Authors: David Esteban‐Gómez | Laura A. Büldt | P. Pérez‐Lourido | Laura Valencia | Michael Seitz | Carlos Platas‐Iglesias
Source: Inorganic Chemistry (article, 2019-03-05)
Field: Materials Science — Materials Chemistry

Understanding the Optical and Magnetic Properties of Ytterbium(III) Complexes The absorption and emission spectra of three Yb<sup>3+</sup> complexes possessing D<sub>3</sub>, D<sub>2</sub>, and C<sub>2</sub> symmetries were analyzed with the aid of ab initio calculations based on Complete Active Space (CAS) self-consistent field wave functions (CAS(13,7)). The absorption spectra present contributions from both cold and hot bands, involving thermally populated excited sublevels of the <sup>2</sup>F<sub>7/2</sub> manifold. The high-resolution emission spectrum of the tris-picolinate complex [Yb(DPA)<sub>3</sub>]<sup>3-</sup> recorded at 77 K presents four components, while the complexes with macrocyclic ligands show both cold and hot emission bands, resulting in more than four components for the <sup>2</sup>F<sub>5/2</sub> → <sup>2</sup>F<sub>7/2</sub> transition. The combined information provided by the absorption and emission spectra allowed to identify most of the crystal field sublevels of the <sup>2</sup>F<sub>5/2</sub> and <sup>2</sup>F<sub>7/2</sub> states. The energies of these crystal field components are well-reproduced by the ab initio calculations, with deviations typically lower than 100 cm<sup>-1</sup>. The crystal field splitting is very sensitive to subtle changes of the Yb<sup>3+</sup> coordination environment. The magnetic anisotropy of [Yb(DPA)<sub>3</sub>]<sup>3-</sup> obtained with ab initio calculations was found to be extremely sensitive to changes in the twist angle of the upper and lower faces of the tricapped trigonal prismatic coordination polyhedron. Ab initio ligand field theory provides a straightforward chemical justification for the changes in magnetic anisotropy, which are responsible for the observed pseudocontact shifts in the NMR spectra. Chemistry ; Ab initio ; Ab initio quantum chemistry methods ; Ligand field theory ; Crystal (programming language) ; Excited state ; Anisotropy ; Spectral line ; Crystallography ; Absorption spectroscopy ; Molecular physics ; Atomic physics ; Ion ; Molecule ; Physics Lanthanide and Transition Metal Complexes ; Magnetism in coordination complexes ; Electron Spin Resonance Studies
Authors: Sergii I. Shylin | Mariia V. Pavliuk | Luca D’Amario | Fikret Mamedov | Jacinto Sá | Gustav Berggren | Igor O. Fritsky
Source: Chemical Communications (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Efficient visible light-driven water oxidation catalysed by an iron(<scp>iv</scp>) clathrochelate complex A water-stable FeIV clathrochelate complex catalyses fast and homogeneous photochemical oxidation of water to dioxygen with a turnover frequency of 2.27 s-1 and a maximum turnover number of 365. An FeV intermediate generated under catalytic conditions is trapped and characterised using EPR and Mössbauer spectroscopy. Chemistry ; Visible spectrum ; Photochemistry ; Stereochemistry ; Materials science ; Optoelectronics Porphyrin and Phthalocyanine Chemistry ; Electrocatalysts for Energy Conversion ; Metal-Catalyzed Oxygenation Mechanisms
Authors: Jiali Zhao | Chen Liu | Jinmei Li | Rui Wu | Jiaou Wang | Haijie Qian | Haizhong Guo | Jiankun Li | Kurash Ibrahim
Source: AIP Advances (article, 2019-05-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Oxygen vacancy induced electronic structure variation in the La0.2Sr0.8MnO3 thin film Oxygen vacancy in different oxide systems shows up as a crucial parameter in modulation of the emerging application-oriented functionalities. A systematic exploration on the relation between oxygen vacancy and electronic structure of the La0.2Sr0.8MnO3 (LSMO) thin film has been carried out through sequential surface treatments followed by a series of wide scan XPS, O 1s XPS, O-K edge XAS, Mn-L edge XAS and work function measurements. Experimental results demonstrate mutual corroborative certifying evidences in between the different photoemission spectral measurements on the evolution and influence of the oxygen vacancy. Spectral characteristic features observed in the work are applicable using as justification fingerprint for the existence, modulation, or elimination of the oxygen vacancy in similar perovskite type oxide systems. X-ray photoelectron spectroscopy ; Vacancy defect ; Oxygen ; Materials science ; X-ray absorption spectroscopy ; Thin film ; Oxide ; Work function ; Electronic structure ; Analytical Chemistry (journal) ; Chemical physics ; Chemistry ; Absorption spectroscopy ; Crystallography ; Nanotechnology ; Nuclear magnetic resonance ; Computational chemistry ; Optics ; Physics ; Metallurgy Magnetic and transport properties of perovskites and related materials ; Electronic and Structural Properties of Oxides ; Advancements in Solid Oxide Fuel Cells