jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Nor Athirah Roslin | Nik Norasma Che’Ya | Nursyazyla Sulaiman | Lutfi Amir Nor Alahyadi | Mohd Razi Ismail
Source: Pertanika journal of science & technology (article, 2021-09-21)
Field: Chemistry — Analytical Chemistry

Mobile Application Development for Spectral Signature of Weed Species in Rice Farming Weed infestation happens when there is intense competition between rice and weeds for light, nutrients and water. These conditions need to be monitored and controlled to lower the growth of weeds as they affected crops production. The characteristics of weeds and rice are challenging to differentiate macroscopically. However, information can be acquired using a spectral signature graph. Hence, this study emphasises using the spectral signature of weed species and rice in a rice field. The study aims to generate a spectral signature graph of weeds in rice fields and develop a mobile application for the spectral signature of weeds. Six weeds were identified in Ladang Merdeka using Fieldspec HandHeld 2 Spectroradiometer. All the spectral signatures were stored in a spectral database using Apps Master Builder, viewed using smartphones. The results from the spectral signature graph show that the jungle rice (Echinochloa spp.) has the highest near-infrared (NIR) reflectance. In contrast, the saromacca grass (Ischaemum rugosum) shows the lowest NIR reflectance. Then, the first derivative (FD) analysis was run to visualise the separation of each species, and the 710 nm to 750 nm region shows the highest separation. It shows that the weed species can be identified using spectral signature by FD analysis with accurate separation. The mobile application was developed to provide information about the weeds and control methods to the users. Users can access information regarding weeds and take action based on the recommendations of the mobile application. Spectral signature ; Weed ; Echinochloa ; Paddy field ; Spectroradiometer ; Agronomy ; Weed control ; Environmental science ; Reflectivity ; Mathematics ; Remote sensing ; Biology ; Geography ; Physics ; Optics Spectroscopy and Chemometric Analyses ; Smart Agriculture and AI ; Identification and Quantification in Food
Authors: Zeinab Adel Nasr | Marwa M. Soliman | Ekram H. Mohamed | Fatma A. Fouad
Source: Acta Chromatographica (article, 2021-05-27)
Field: Chemistry — Spectroscopy

Assessment of the greenness of micellar HPLC method for rapid separation and simultaneous estimation of chlorpheniramine maleate in presence of some co-administered drugs in three pharmaceutical dosage forms using single run Abstract Sustainable chemistry established one of kind standards to maintain protection of environment through using safer mobile phase composition and/or lower solvent consumption. A fast green micellar HPLC method was developed and applied for the first time aiming at simultaneous determination of chlorpheniramine maleate, one of the most widely used antihistamine in combination with levochlopersatine fenodizoate or dextromethorphan hydrobromide or dexamethasone, in their pure forms, laboratory prepared mixtures and pharmaceutical dosage forms used in alleviating the symptoms of cough resulting from common colds and allergy. The separation was achieved on Kinetex C 18 column (100 mm × 4.6 mm i.d., 2.6-μm particle size) using micellar aqueous mobile phase consisting of (30 mM sodium dodecyl sulfate and 50 mM sodium dihydrogen phosphate, pH 5) and ethanol (85:15) with UV detection at 230 nm. The four drugs were successfully separated using isocratic elution in a single run not exceeding 7 min. According to ICH guidelines, the method was confirmed to be linear, accurate and precise over the concentration ranges of 5–60 μg mL −1 for chlorpheniramine maleate, 10–100 μg mL −1 for levocloperastine fenodizoate and dextromethorphan hydrobromide and 5–30 μg mL −1 for dexamethasone. In addition, the greenness of the developed method was assessed using two different tools indicating their least hazardous effect on the environment. Chemistry ; Chromatography ; Chlorpheniramine Maleate ; Dosage form ; Sodium dodecyl sulfate ; High-performance liquid chromatography ; Micellar liquid chromatography ; Brucine ; Pharmaceutical formulation ; Aqueous solution ; Micelle ; Organic chemistry Analytical Chemistry and Chromatography ; Analytical Methods in Pharmaceuticals ; Analytical Chemistry and Sensors
Authors: Lenard Röder | Horst Fischer
Source: Applied Physics B (article, 2021-12-29)
Field: Chemistry — Spectroscopy

Theoretical investigation of applicability and limitations of advanced noise reduction methods for wavelength modulation spectroscopy Abstract In this study, the applicability and limitations of several statistical and mathematical methods for noise reduction in wavelength modulation spectroscopy are analyzed. Background noise is simulated for different frequencies and frequency confinement. The noise is added to an absorption line of varying amplitude. The noise reduction methods (NRMs) are applied to the simulated signals and their performances are analyzed and compared. All NRMs show great increase in signal to noise ratio (SNR) while keeping bias low under certain conditions of the simulated signal. For each NRM the subspace of best performance is summarized and highlighted. Little to no overlap is found between these subspaces. Therefore, the optimal NRM strongly depends on measurement conditions and NRM quality cannot be compared in a general context. Noise (video) ; Context (archaeology) ; Noise reduction ; Optics ; Modulation (music) ; Signal-to-noise ratio (imaging) ; Reduction (mathematics) ; Wavelength ; SIGNAL (programming language) ; Acoustics ; Computer science ; Computational physics ; Materials science ; Physics ; Mathematics ; Artificial intelligence Spectroscopy and Laser Applications ; Spectroscopy and Chemometric Analyses ; Water Quality Monitoring and Analysis
Authors: Pablo Alonso González | Eva Parga‐Dans | Paula Arribas Blázquez | Octavio P. Luzardo | Manuel Luis Zumbado Peña | María Mercedes Hernández González | Ángel Rodríguez-Hernández | Carmelo Andújar
Source: PLoS ONE (article, 2021-11-03)
Field: Chemistry — Analytical Chemistry

Elemental composition, rare earths and minority elements in organic and conventional wines from volcanic areas: The Canary Islands (Spain) The organic wine market is rapidly growing worldwide, both in terms of production and consumption. However, the scientific literature is not conclusive regarding differences in the elemental composition of wines according to their production method, including both major and trace elements. Minerals can be present in wine as a result of both anthropogenic and environmental factors. To date, this has not been evaluated in volcanic contexts, neither has the emergent issue of rare earths and other minority elements as potential sources of food contamination. This study using inductively coupled plasma mass spectrometry (ICP-MS) analyses organic and conventional wines produced in the Canary Islands (Spain), an archipelago of volcanic origin, to compare their content of 49 elements, including rare earths and minority elements. Our results showed that organic wines presented lower potential toxic element content on average than their conventional counterparts, but differences were not significant. Geographical origin of the wine samples (island) was the only significant variable differentiating wine samples by their composition profiles. By comparing our data with the literature, no agreement was found in terms of differences between organic and conventionally-produced wines. This confirms that other factors prevail over elemental composition when considering differences between wine production methods. Regarding the toxicological profile of the wines, five samples (three organic and two conventional) exceeded the maximum limits established by international legislation. This highlights the need for stricter analytical monitoring in the Canary Islands, with a particular focus on Cu and Ni concentration, and potentially in other volcanic areas. Wine ; Volcano ; Composition (language) ; Inductively coupled plasma mass spectrometry ; Environmental science ; Environmental chemistry ; Trace element ; Archipelago ; Mineralogy ; Chemistry ; Geography ; Geology ; Geochemistry ; Food science ; Mass spectrometry ; Archaeology Heavy Metals in Plants ; Isotope Analysis in Ecology ; Fermentation and Sensory Analysis
Authors: Sławomir Kozieł | Muhammad Syafiq Abdullah | Stanisław Szczepański
Source: IEEE Access (article, 2021-01-01)
Field: Materials Science — Electronic, Optical and Magnetic Materials

Design of High-Performance Scattering Metasurfaces Through Optimization-Based Explicit RCS Reduction The recent advances in the development of coding metasurfaces created new opportunities in realization of radar cross section (RCS) reduction. Metasurfaces, composed of optimized geometries of meta-atoms arranged as periodic lattices, are devised to obtain desired electromagnetic (EM) scattering characteristics. Despite potential benefits, their rigorous design methodologies are still lacking, especially in the context of controlling the EM wavefront through parameter tuning of meta-atoms. One of the practical obstacles hindering efficient design of metasurfaces is implicit handling of RCS performance. To achieve essential RCS reduction, the design task is normally formulated in terms of phase reflection characteristics of the meta-atoms, whereas their reflection amplitudes-although contributing to the overall performance of the structure-is largely ignored. As a result, the conventional approaches are unable to determine truly optimum solutions. This article proposes a novel formulation of the metasurface design task with explicit handling of RCS reduction at the level of meta-atoms. Our methodology accounts for both the phase and reflection amplitudes of the unit cells. The design objective is defined to directly optimize the RCS reduction bandwidth at the specified level (e.g., 10 dB) w.r.t. the metallic surface. The benefits of the presented scheme are twofold: (i) it provides a reliable insight into the metasurface properties even though the design process is carried out at the level of meta-atoms, (ii) the obtained design requires minimum amount of tuning at the level of the entire metasurface. None of these is possible for phase-response-based approach fostered in the literature. For practical purposes, the design is conducted using a surrogate-assisted procedure involving kriging metamodels, which enables global optimization at a low computational cost. To corroborate the utility of our formulation, a high-performance metasurface incorporating crusader-cross-shaped meta-atoms has been developed. The obtained results indicate that the system characteristics predicted at the design stage are well aligned with those of the EM-simulated structure (which is not the case for the traditional design approach). The metasurface features 10-dB RCS reduction in the frequency range of 16.5 GHz to 34.6 GHz, as validated both numerically and experimentally. Radar cross-section ; Reduction (mathematics) ; Computer science ; Context (archaeology) ; Bandwidth (computing) ; Scattering ; Wavefront ; Reflection (computer programming) ; Phase (matter) ; Electromagnetics ; Electronic engineering ; Optics ; Physics ; Mathematics ; Engineering ; Telecommunications Metamaterials and Metasurfaces Applications ; Advanced Antenna and Metasurface Technologies ; Antenna Design and Analysis
Authors: Ning Su | Fangfang Pan | Liusan Wang | Shizhuang Weng
Source: Biosensors (article, 2021-08-03)
Field: Chemistry — Analytical Chemistry

Rapid Detection of Fatty Acids in Edible Oils Using Vis-NIR Reflectance Spectroscopy with Multivariate Methods The composition and content of fatty acids are critical indicators to identify the quality of edible oils. This study was undertaken to establish a rapid determination method for quality detection of edible oils based on quantitative analysis of palmitic acid, stearic acid, arachidic acid, and behenic acid. Seven kinds of oils were measured to obtain Vis-NIR spectra. Multivariate methods combined with pretreatment methods were adopted to establish quantitative analysis models for the four fatty acids. The model of support vector machine (SVM) with standard normal variate (SNV) pretreatment showed the best predictive performance for the four fatty acids. For the palmitic acid, the determination coefficient of prediction (RP2) was 0.9504 and the root mean square error of prediction (RMSEP) was 0.8181. For the stearic acid, RP2 and RMSEP were 0.9636 and 0.2965. In the prediction of arachidic acid, RP2 and RMSEP were 0.9576 and 0.0577. In the prediction of behenic acid, the RP2 and RMSEP were 0.9521 and 0.1486. Furthermore, the effective wavelengths selected by successive projections algorithm (SPA) were useful for establishing simplified prediction models. The results demonstrate that Vis-NIR spectroscopy combined with multivariate methods can provide a rapid and accurate approach for fatty acids detection of edible oils. Behenic acid ; Stearic acid ; Palmitic acid ; Arachidic acid ; Chemistry ; Multivariate statistics ; Fatty acid ; Chromatography ; Food science ; Mathematics ; Biochemistry ; Statistics ; Organic chemistry Spectroscopy and Chemometric Analyses ; Advanced Chemical Sensor Technologies ; Spectroscopy Techniques in Biomedical and Chemical Research
Authors: Vincent Pepermans | Soraya Chapel | Sabine Heinisch | Gert Desmet
Source: Journal of Chromatography A (article, 2021-03-18)
Field: Chemistry — Spectroscopy

Detailed numerical study of the peak shapes of neutral analytes injected at high solvent strength in short reversed-phase liquid chromatography columns and comparison with experimental observations Chemistry ; Chromatography ; Solvent ; Analyte ; Volume (thermodynamics) ; Analytical Chemistry (journal) ; Acetonitrile ; Phase (matter) ; High-performance liquid chromatography ; Reversed-phase chromatography ; Volume fraction ; Theoretical plate ; Thermodynamics Analytical Chemistry and Chromatography ; Chromatography in Natural Products ; Microfluidic and Capillary Electrophoresis Applications
Authors: Jiarui Fan | Cheng Ai | Aofei Guo | Xiaojun Yan | Jingang Wang
Source: Sensors (article, 2021-06-25)
Field: Materials Science — Materials Chemistry

Evaluation of Electric Field Integral Voltage Measurement Method of Transmission Line Based on Error Transmission and Uncertainty Analysis Electric field numerical integration algorithms can realize the non-contact measurement of transmission line voltage effectively. Although there are many electric field numerical integration algorithms, lack of a comprehensive comparison of accuracy and stability among various algorithms results in difficulties in evaluating the measurement results of various algorithms. Therefore, this paper presents the G-L (Gauss-Legendre) algorithm, the I-G-L (improved Gauss-Legendre) algorithm, and the I-G-C (improved Gauss-Chebyshev) algorithm and proposes a unified error propagation model of the derived algorithms to assess the accuracy of each integration method by considering multiple error sources. Moreover, evaluation criteria for the uncertainty of transmission line voltage measurement are proposed to analyze the stability and reliability of these algorithms. A simulation model and experiment platform were then constructed to conduct error propagation and uncertainty analyses. The results show that the G-L algorithm had the highest accuracy and stability in the scheme with five integral nodes, for which the simulation error was 0.603% and the relative uncertainty was 2.130%. The I-G-L algorithm was more applicable due to the smaller number of integral nodes required, yet the algorithm was less stable in achieving the same accuracy as the G-L algorithm. In addition, the I-G-C algorithm was relatively less accurate and stable in voltage measurement. Algorithm ; Propagation of uncertainty ; Transmission line ; Stability (learning theory) ; Computer science ; Transmission (telecommunications) ; Voltage ; Measurement uncertainty ; Approximation error ; Gauss ; Reliability (semiconductor) ; Mathematics ; Engineering ; Telecommunications ; Statistics ; Electrical engineering High voltage insulation and dielectric phenomena ; Lightning and Electromagnetic Phenomena ; Thermal Analysis in Power Transmission
Authors: Yong Liu | Qiran Li | Boxue Du | M. Farzaneh
Source: Scientific Reports (article, 2021-01-28)
Field: Materials Science — Materials Chemistry

Feature extraction and classification of surface discharges on an ice-covered insulator string during AC flashover using gray-level co-occurrence matrix This study focuses on the feature extraction and classification of surface discharges of ice-covered insulator strings during process of alternating current flashover. The test specimen was the five units suspension ceramic insulators, which was artificially accreted with wet-grown ice in the cold-climate room of CIGELE. Based on the IEEE Standard 1783/2009, flashover experiments were conducted on iced insulators to measure the minimum flashover voltage (VMF) and record the propagating process of surface discharges to flashover by using a high-speed video camera. The gray-level co-occurrence matrix (GLCM) method has been used to extract four parameters of arc discharge images features that characterize different stages of flashover process. The parameters are angular second moment (ASM), contrast (CON), inverse difference moment (IDM) and entropy (ENT). These statistical parameters of GLCM can be extracted to reveal the underlying properties of ice flashover on the insulator surface from the quantitative perspective. The different values of these indicators are representative of the different stages in the process of arc discharge. Once the value of quantitative indicators (ASM, CON, IDM, ENT) of surface discharges exceeds the threshold value, the higher flashover risk of iced insulators will appear. Hence, the proposed methods are helpful to understand and monitor surface discharge on iced outdoor insulator strings for preventing flashover accidents. Arc flash ; Insulator (electricity) ; Materials science ; Composite material ; Environmental science ; Forensic engineering ; Engineering High voltage insulation and dielectric phenomena ; Power Transformer Diagnostics and Insulation ; Electrical Fault Detection and Protection
Authors: Stavros D. Peroukidis | Dimitris G. Mintis | Ian P. Stott | Vlasis G. Mavrantzas
Source: Journal of Physics Materials (article, 2021-05-12)
Field: Chemistry — Organic Chemistry

Molecular simulation of the morphology and viscosity of aqueous micellar solutions of sodium lauryl ether sulfate (SLEnS) Abstract In a recent contribution, we introduced a new approach for the quantitative prediction of the micellar morphology of aqueous solutions of ionic surfactants based on coarse-grained MARTINI-type simulations followed by reverse-mapped all-atom (AA) molecular dynamics (MD) ones, using as a model system sodium dodecyl sulfate. We make use of the same approach in the present work to study the micellar structure of aqueous solutions of sodium lauryl ether sulfate (SLE n S) with the chemical structure CH 3 (CH 2 ) 11 (OCH 2 CH 2 ) n OSO 3 Na with a fixed number n of ethoxyl (EO) groups per surfactant molecule ( n = 1, 2, 3). These surfactants are used in a wide range of industrial applications, particularly in personal and home care products, but a quick literature survey proves that a systematic study of their microstructure, micellar morphology, and equilibrium transport properties is missing. Our simulations provide predictions for the mean aggregation number of such monodisperse SLE n S solutions which are found to be in very good agreement with experimental data already reported in the literature. They also show that for a given total surfactant concentration, SLE n S molecules with a smaller number n of EO groups form, on average, larger micelles. From the reverse-mapped AA MD simulations we also compute the zero shear rate viscosity of the solution whose value is found to increase as its total concentration in SLE n S molecules increases (for a given n ) or as the number n of EO groups in the surfactant increases (for a given concentration). Aqueous solution ; Pulmonary surfactant ; Micelle ; Chemistry ; Ether ; Sodium dodecyl sulfate ; Dispersity ; Viscosity ; Molecule ; Physical chemistry ; Thermodynamics ; Polymer chemistry ; Organic chemistry ; Physics Surfactants and Colloidal Systems ; Spectroscopy and Quantum Chemical Studies ; Electrostatics and Colloid Interactions
Authors: Christopher M. Bottoms | Tanguy Terlier | Gila E. Stein | Manolis Doxastakis
Source: Macromolecules (article, 2021-02-11)
Field: Materials Science — Materials Chemistry

Ion Diffusion in Chemically Amplified Resists The acid-catalyzed deprotection of glassy polymer resins is an important process in semiconductor lithography. Studies have shown that the reaction kinetics in these materials is controlled by slow diffusion of the acid–anion catalyst, but trends deviate from models of a first-order reaction coupled to a composition-invariant Fickian diffusivity. We present a concerted experimental and computational effort to examine catalyst diffusion in a model resin of poly(4-hydroxystyrene-co-tert-butyl acrylate-co-styrene), or P(HOSt-tBA-St), which is deprotected in the presence of an acid catalyst to poly(4-hydroxystyrene-co-acrylic acid-co-styrene), or P(HOSt-AA-St). We employed an inert catalyst analogue to examine long-time ion dynamics in both terpolymers with atomistic molecular dynamics simulations and compared the calculated Fickian diffusivities with direct measurements of ion diffusion fronts using time-of-flight secondary ion mass spectrometry. Our results demonstrate that ion diffusivities in P(HOSt-tBA-St) and in P(HOSt-AA-St) are similar near and below the glass transition, consistent with a diffusion process that is dominated by interactions with the polar HOSt units. We then compared the bulk reaction kinetics measured by Fourier-transform infrared spectroscopy with reaction kinetics obtained using mesoscopic reaction–diffusion models. We found that initial reaction kinetics is significantly accelerated compared to predictions based on the long-time ion diffusivities of our inert system. This study highlights the potential of atomistic modeling coupled with targeted experiments for interrogating the physical and chemical processes that control pattern formation in next-generation lithographic materials. Chemistry ; Catalysis ; Kinetics ; Diffusion ; Fick's laws of diffusion ; Chemical kinetics ; Ion ; Physical chemistry ; Polymer chemistry ; Analytical Chemistry (journal) ; Organic chemistry ; Thermodynamics Block Copolymer Self-Assembly ; Material Dynamics and Properties ; Microfluidic and Capillary Electrophoresis Applications
Authors: Lakshmi Prasanna Lingamdinne | Suhyun Lee | Yoon‐Young Chang | Janardhan Reddy Koduru | Jae‐Kyu Yang
Source: Synthetic Metals (article, 2021-01-13)
Field: Chemistry — Inorganic Chemistry

Facile synthesis of lanthanum hydroxide doped graphene oxide for scavenged of radioactive and heavy elements from water Adsorption ; X-ray photoelectron spectroscopy ; Lanthanum ; Aqueous solution ; Oxide ; Hydroxide ; Fourier transform infrared spectroscopy ; Scanning electron microscope ; Inorganic chemistry ; Nuclear chemistry ; Graphene ; Materials science ; Chemistry ; Chemical engineering ; Nanotechnology ; Physical chemistry ; Organic chemistry Radioactive element chemistry and processing ; Extraction and Separation Processes ; Adsorption and biosorption for pollutant removal