jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Yukari Katsura | H. Takagi | Kaoru Kimura
Source: MATERIALS TRANSACTIONS (article, 2018-04-26)
Field: Materials Science — Materials Chemistry

Roles of Carrier Doping, Band Gap, and Electron Relaxation Time in the Boltzmann Transport Calculations of a Semiconductor’s Thermoelectric Properties Although there is a growing demand for first-principles predictions of the thermoelectric properties of materials, the contribution of various errors in Boltzmann transport calculations is not negligible. We conducted a typical first-principles calculation and a Boltzmann transport analysis on a typical semiconductor (Si) at various temperatures T while varying the band gap εg, electron relaxation time τel, and phonon thermal conductivity κph to demonstrate how the calculated thermoelectric properties, which are functions of the carrier doping level, are affected by these parameters. Bipolar conduction drastically decreased zT via a degradation of the Seebeck coefficient S and an increase in the effective Lorenz factor Leff, indicating the importance of a wide enough εg (several multiples of kBT or higher) for high zT. Thus, the underestimation of εg, which frequently happens in first-principles calculations, could induce large errors in calculations for narrow-gap semiconductors. The calculation of the electron thermal conductivity without Peltier thermal conductivity was found to limit the zT of typical semiconductors to below 1. A small value of κph/τel, where κph/τel is the degree to which a material is a phonon-glass electron-crystal, was necessary to achieve a high zT. Fitting the calculations with experimental thermoelectric properties showed that τel can vary by an order of magnitude from 10−15 to 10−14 s, depending on both T and the samples. This indicates that the use of a fixed relaxation time is inappropriate for thermoelectric materials. Thermoelectric effect ; Condensed matter physics ; Materials science ; Seebeck coefficient ; Thermal conductivity ; Boltzmann equation ; Semiconductor ; Thermoelectric materials ; Boltzmann constant ; Thermal conduction ; Band gap ; Doping ; Electrical resistivity and conductivity ; Electron mobility ; Relaxation (psychology) ; Thermodynamics ; Physics ; Optoelectronics Advanced Thermoelectric Materials and Devices ; Thermal properties of materials ; Machine Learning in Materials Science
Authors: Handattu Sankara Narayana Akshatha | Bannimath Gurupadayya
Source: Asian Journal of Pharmaceutical and Clinical Research (article, 2018-05-01)
Field: Chemistry — Spectroscopy

APPLICATION OF LIQUID CHROMATOGRAPHY COUPLED WITH MASS SPECTROMETRY IN THE IMPURITY PROFILING OF DRUG SUBSTANCES AND PRODUCTS As the drug safety and efficacy is hampered in the presence of an impurity, the international regulatory agencies laid down stringent limits for the control of impurities in the active pharmaceutical ingredient and pharmaceutical formulations. The conventional approaches lack the characterization of impurities in trace levels, due to sensitivity issues, hyphenated techniques are preferred. Among the modern hyphenated techniques, liquid chromatography-mass spectrometry (LC-MS) has high sensitivity and can analyze large number of organic compounds in a short period of time. In the present study, the impurity profiling of various drug substances and products using LC-MS about past 6 years were retrospect for its importance, instrumentations, and applications. Impurity ; Chromatography ; Mass spectrometry ; Chemistry ; Active ingredient ; Liquid chromatography–mass spectrometry ; High-performance liquid chromatography ; Drug ; Organic chemistry ; Pharmacology ; Medicine Analytical Chemistry and Chromatography ; Analytical Methods in Pharmaceuticals ; Pesticide Residue Analysis and Safety
Authors: E. Bagherpour | M. Reihanian | N. Pardis | R. Ebrahimi | Terence G. Langdon
Source: Brunel University Research Archive (BURA) (Brunel University London) (article, 2018-04-30)
Field: Materials Science — Materials Chemistry

Ten years of severe plastic deformation (SPD) in Iran, part I: equal channel angular pressing (ECAP) The superior properties of ultrafine-grained materials fabricated by severe plastic deformation (SPD) have attracted the attention of many researchers around the world. Among the top-ranked countries that are active in this field, Iran is interesting because of the late beginnings of SPD in this country and, subsequently, the highest rate of growth in the number of publications during the last decade. The first Iranian work published in the field of equal-channel angular pressing (ECAP) goes back to 2007, meaning that SPD research covers a period of only about ten years. Nevertheless, since that time there has been an increasing growth rate in the number of Iranian publications dealing with ECAP and especially the introduction of new methods based on ECAP and simulation of the method. The present overview is designed to summarize the main contributions from Iran in the field of ECAP processing. Interestingly, the main contribution of Iranian researchers in ECAP is focused on simulation/modelling and the introduction of new methods of SPD based on ECAP. Pressing ; Severe plastic deformation ; Materials science ; Metallurgy ; Channel (broadcasting) ; Engineering ; Composite material ; Telecommunications Microstructure and mechanical properties ; Metal Forming Simulation Techniques ; Metallurgy and Material Forming
Authors: Yiwa Luo | Hanjie Guo | Jing Guo | Wensheng Yang
Source: Materials (article, 2018-12-18)
Field: Materials Science — Materials Chemistry

Gleeble-Simulated and Semi-Industrial Studies on the Microstructure Evolution of Fe-Co-Cr-Mo-W-V-C Alloy during Hot Deformation Fe-Co-Cr-Mo-W-V-C alloy is one of the most important materials for manufacturing drills, dies, and other cutting tools owing to its excellent hardness. However, it is prone to cracking due to its poor hot ductility during continuous hot working processes. In this investigation, the microstructure characteristics and carbide transformations of the alloy in as-cast and wrought states are studied, respectively. Microstructural observation and first-principles calculation were conducted on the research of types and mechanical properties of carbides. The results reveal that carbides in as-cast Fe-Co-Cr-Mo-W-V-C alloy are mainly Mo₂C, VC, and Cr-rich carbides (Cr₇C₃ and Cr<sub>23</sub>C₆). The carbides in wrought Fe-Co-Cr-Mo-W-V-C alloy consist of Fe₂Mo₄C, VC, Cr₇C₃, and a small amount of retained Mo₂C. For these carbides, Cr₇C₃ presents the maximum bulk modulus and B/G values of 316.6 GPa and 2.48, indicating Cr₇C₃ has the strongest ability to resist the external force and crack initiation. VC presents the maximum shear modulus and Yong's modulus values of 187.3 GPa and 465.3 GPa, which means VC can be considered as a potential hard material. Hot isothermal compression tests were performed using a Gleeble-3500 device to simulate the flow behavior of the alloy during hot deformation. As-cast specimens were uniaxially compressed to a 70% height reduction over the temperature range of 1323⁻1423 K and strain rates of 0.05⁻1 s<sup>-1</sup>. A constitutive equation was established to characterize the relationship of peak true stress, strain rate, and deformation temperature of the alloy. The calculated results were in a good agreement with the experimental data. In order to study the texture evolution, the microstructures of the deformed specimens were observed, and an optimal deformation temperature was selected. Using the laboratorial optimal temperature (1373 K) in forging of an industrial billet resulted in uniform grains, with the largest size of 17 µm, surrounded by homogenous spherical carbides. Microstructure ; Materials science ; Alloy ; Deformation (meteorology) ; Metallurgy ; Composite material Metal Alloys Wear and Properties ; Advanced materials and composites ; Microstructure and Mechanical Properties of Steels
Authors: Ananda Hegde | Sathyashankara Sharma | Gowri Shankar M. C
Source: JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES (review, 2018-12-27)
Field: Materials Science — Materials Chemistry

Machinability and related properties of austempered ductile iron: A review When the ductile iron which is also known as Spheroidal Graphite (SG) iron, is subjected to austempering heat treatment, the material is known as austempered ductile iron (ADI). This material has good mechanical properties and has various applications in different fields. This revolutionary material with its excellent combination of strength, ductility, toughness and wear resistance has the potential to replace some of the commonly used conventional materials such as steel, aluminium and other light weight alloys as it offers production advantage as well. One of the problems encountered during manufacturing is machining of ADI parts owing to its high hardness and wear resistance. Many researchers over a period of time have reported the machinability aspects of the ADI. This paper presents a review on the developments made on the machinability aspects of ADI along with other mechanical properties. Machinability ; Austempering ; Materials science ; Ductility (Earth science) ; Metallurgy ; Cast iron ; Machining ; Toughness ; Aluminium ; Ductile iron ; Graphite ; Microstructure ; Austenite Metal Alloys Wear and Properties ; Advanced machining processes and optimization ; Advanced Surface Polishing Techniques
Authors: Caroline König | Ilmira Shaim | Alfredo Vellido | Enrique Romero | René Alquézar | Jesús Giraldo
Source: Scientific Reports (article, 2018-06-29)
Field: Chemistry — Spectroscopy

Using machine learning tools for protein database biocuration assistance Biocuration in the omics sciences has become paramount, as research in these fields rapidly evolves towards increasingly data-dependent models. As a result, the management of web-accessible publicly-available databases becomes a central task in biological knowledge dissemination. One relevant challenge for biocurators is the unambiguous identification of biological entities. In this study, we illustrate the adequacy of machine learning methods as biocuration assistance tools using a publicly available protein database as an example. This database contains information on G Protein-Coupled Receptors (GPCRs), which are part of eukaryotic cell membranes and relevant in cell communication as well as major drug targets in pharmacology. These receptors are characterized according to subtype labels. Previous analysis of this database provided evidence that some of the receptor sequences could be affected by a case of label noise, as they appeared to be too consistently misclassified by machine learning methods. Here, we extend our analysis to recent and quite substantially modified new versions of the database and reveal their now extremely accurate labeling using several machine learning models and different transformations of the unaligned sequences. These findings support the adequacy of our proposed method to identify problematic labeling cases as a tool for database biocuration. Computer science ; Database ; Bioinformatics ; World Wide Web ; Computational biology ; Data science ; Biology Advanced Proteomics Techniques and Applications ; Gene expression and cancer classification ; Machine Learning in Bioinformatics
Authors: Avinash M. Dongare | A. M. Rajendran | Raju R. Namburu | Madan Dubey
Source: Journal of Materials Science (article, 2018-01-18)
Field: Materials Science — Materials Chemistry

Understanding mechanical behavior of interfaces in materials Materials science ; Solid mechanics ; Composite material ; Polymer science Machine Learning in Materials Science ; Titanium Alloys Microstructure and Properties ; Microstructure and mechanical properties
Authors: Catarina Moreirinha | Joana Trindade | Jorge A. Saraiva | Adelaide Almeida | Ivonne Delgadillo
Source: Journal of Food Science and Technology (article, 2018-07-09)
Field: Chemistry — Analytical Chemistry

MIR spectroscopy as alternative method for further confirmation of foodborne pathogens Salmonella spp. and Listeria monocytogenes Listeria monocytogenes ; Salmonella ; Listeria ; Foodborne pathogen ; Biology ; Food microbiology ; Pathogen ; Food products ; Food science ; Microbiology ; Biotechnology ; Bacteria Spectroscopy and Chemometric Analyses ; Spectroscopy Techniques in Biomedical and Chemical Research ; Listeria monocytogenes in Food Safety
Authors: Estela Kamile Gelinski | Fabiane Hamerski | Marcos L. Corazza | Alexandre F. Santos
Source: The Open Chemical Engineering Journal (article, 2018-11-14)
Field: Chemistry — Analytical Chemistry

Biodiesel Synthesis Monitoring using Near Infrared Spectroscopy Objective: Biodiesel is a renewable fuel considered as the main substitute for fossil fuels. Its industrial production is mainly made by the transesterification reaction. In most processes, information on the production of biodiesel is essentially done by off-line measurements. Methods: However, for the purpose of control, where online monitoring of biodiesel conversion is required, this is not a satisfactory approach. An alternative technique to the online quantification of conversion is the near infrared (NIR) spectroscopy, which is fast and accurate. In this work, models for biodiesel reactions monitoring using NIR spectroscopy were developed based on the ester content during alkali-catalyzed transesterification reaction between soybean oil and ethanol. Gas chromatography with flame ionization detection was employed as the reference method for quantification. FT-NIR spectra were acquired with a transflectance probe. The models were developed using Partial Least Squares (PLS) regression with synthetic samples at room temperature simulating reaction composition for different ethanol to oil molar ratios and conversions. Model predictions were then validated online for reactions performed with ethanol to oil molar ratios of 6 and 9 at 55ºC. Standard errors of prediction of external data were equal to 3.12%, hence close to the experimental error of the reference technique (2.78%), showing that even without using data from a monitored reaction to perform calibration, proper on-line predictions were provided during transesterification runs. Results: Additionally, it is shown that PLS models and NIR spectra of few samples can be combined to accurately predict the glycerol contents of the medium, making the NIR spectroscopy a powerful tool for biodiesel production monitoring. Transesterification ; Biodiesel ; Partial least squares regression ; Calibration ; Biodiesel production ; Spectroscopy ; Chemistry ; Near-infrared spectroscopy ; Gas chromatography ; Biofuel ; Chemometrics ; Analytical Chemistry (journal) ; Materials science ; Chromatography ; Organic chemistry ; Waste management ; Catalysis ; Mathematics ; Computer science ; Machine learning ; Statistics Spectroscopy and Chemometric Analyses ; Biodiesel Production and Applications ; Fault Detection and Control Systems
Authors: Hak Seung Lee | Chaolun Zheng | Bao Yang
Source: Journal of Applied Mechanical Engineering (article, 2018-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Separation of Water-in-Oil Emulsions by Electrostatic Field at the Elevated Temperature Separation of water from oil emulsions has been a significant subject in the petroleum industry and chemical processing. In this paper, we report experimental studies on separation of water from water-in-sunflower oil emulsions under a combined treatment of a radial electric field and elevated temperature. The effects of voltage and temperature on separation time are investigated experimentally and theoretically. It is found that the increase in voltage and/or temperature can significantly reduce the separation time and the residual water in the emulsion. For example, the application of the 1 kV voltages can reduce the separation time by 5-10 times and decrease the residual water concentration by 4-5 times when compared to the process without electric fields. Increasing the process temperature to 90C can also reduce the separation time by 5-10 times and decrease the residual water concentration by 5-6 times when compared to the processes at 25C. The modeling analysis suggests that the enhanced separation performance can be mainly attributed to the reduced viscosity at elevated temperature and the accelerated droplet coalescence under the radial electric field. An optimized condition is also found to balance the energy consumption and separation efficiency. Field (mathematics) ; Water in oil ; Biochemical engineering ; Chemical engineering ; Computer science ; Chemistry ; Nanotechnology ; Emulsion ; Process engineering ; Petroleum engineering ; Chromatography ; Materials science ; Engineering ; Mathematics Electrostatics and Colloid Interactions ; Electrohydrodynamics and Fluid Dynamics ; Field-Flow Fractionation Techniques
Authors: Étienne Audureau | Angélique Simon-Deckers | Marie‐Laure Franco‐Montoya | Balasubramanyam Annangi | Ali Kermanizadeh | Jorge Boczkowski | Sophie Lanone
Source: Scientific Reports (article, 2018-05-29)
Field: Materials Science — Materials Chemistry

Substantial modification of the gene expression profile following exposure of macrophages to welding-related nanoparticles Anthropic nanoparticles (NP) are increasingly produced and emitted, with accompanying concerns for human health. Currently there is no global understanding as to the exact mechanistics of NP toxicity, as the traditional nanotoxicological approaches only provide a restricted overview. To address this issue, we performed an in-depth transcriptomic analysis of human macrophages exposed to a panel of welding-related metal oxide NP that we previously identified in welders lungs (Fe<sub>2</sub>O<sub>3</sub>, Fe<sub>3</sub>O<sub>4</sub>, MnFe<sub>2</sub>O<sub>4</sub> and CrOOH NP). Utilizing the specified analysis criteria (|fold change| ≥1.5, p ≤ 0.001), a total of 2164 genes were identified to be differentially expressed after THP-1 macrophage exposure to the different NP. Performing Gene Ontology enrichment analysis, for cellular content, biological processes and Swiss-Prot/Protein Information Resource keywords the data show for the first time a profound modification of gene differential expression in response to the different NP, among which MnFe<sub>2</sub>O<sub>4</sub> NP were the most potent to induce THP-1 macrophage activation. The transcriptomic analysis utilized in the study, provides novel insights into mechanisms that could contribute to NP-induced adverse effects and support the need for widened approaches to supplement existing knowledge of the processes underlying NP toxicity which would have not been possible using traditional nanotoxicological studies. Transcriptome ; Gene ontology ; Gene ; Gene expression ; Macrophage ; Computational biology ; Gene expression profiling ; Bioinformatics ; Chemistry ; Biology ; Biochemistry ; In vitro Nanoparticles: synthesis and applications ; Microplastics and Plastic Pollution ; Graphene and Nanomaterials Applications
Authors: Jia Jin | Quan Wang
Source: International Journal of Applied Earth Observation and Geoinformation (article, 2018-09-08)
Field: Chemistry — Analytical Chemistry

Informative bands used by efficient hyperspectral indices to predict leaf biochemical contents are determined by their relative absorptions Hyperspectral imaging ; Mathematics ; Geography ; Remote sensing ; Cartography Spectroscopy and Chemometric Analyses ; Remote Sensing in Agriculture ; Leaf Properties and Growth Measurement
Authors: Mahdjoubi Abdelhalim | Boubakeur Zegnini | Mohammed Belkheiri
Source: Diagnostyka (article, 2018-11-27)
Field: Materials Science — Materials Chemistry

Prediction of critical flashover voltage of polluted insulators under sec and rain conditions using least squares support vector machines (LS-SVM) This paper describes a methodology that was developed for the prediction of the critical flashover voltage of polluted insulators under sec and rain conditions least squares support vector machines (LS-SVM) optimization. The methodology uses as input variable characteristics of the insulator such as diameter, height, creepage distance, and the number of elements on a chain of insulators. The estimation of the flashover performance of polluted insulators is based on field experience and laboratory tests are invaluable as they significantly reduce the time and labour involved in insulator design and selection. The majority of the variables to be predicted are dependent upon several independent variables. The results from this work are useful to predict the contamination severity, critical flashover voltage as a function of contamination severity, arc length, and especially to predict the flashover voltage. The validity of the approach was examined by testing several insulators with different geometries. A comparison with the Grouping Multi-Duolateration Localization (GMDL) method proves the accuracy and goodness of LS-SVM. Moreover LS-SVMs give a good estimation of results which are validated by experimental tests. Support vector machine ; Arc flash ; Voltage ; Least squares support vector machine ; Least-squares function approximation ; Computer science ; Pattern recognition (psychology) ; Artificial intelligence ; Engineering ; Mathematics ; Statistics ; Electrical engineering High voltage insulation and dielectric phenomena ; Image and Signal Denoising Methods ; Image Enhancement Techniques
Authors: Arif Cahyo Imawan | Yehezkiel Steven Kurniawan | Muhammad Fernadi Lukman | Jumina Jumina | Triyono Triyono | Dwi Siswanta
Source: Indonesian Journal of Chemistry (article, 2018-02-28)
Field: Materials Science — Polymers and Plastics

Synthesis and Kinetic Study of the Urea Controlled Release Composite Material: Sodium Lignosulfonate from Isolation of Wood Sawdust-Sodium Alginate-Tapioca A synthesis and kinetic study of the urea controlled-release composite material based on isolated Na-lignosulfonate, Na-alginate and tapioca was carried out. This experiment’s aims were to isolate Na-lignosulfonate from wood sawdust and to applicate this isolated Na-lignosulfonate, along with tapioca and Na-alginate as urea control release composite material. A kinetic study of urea released from the composite materials was also conducted. Na-lignosulfonate was isolated by Kraft lignin method to give a brown solid yield of 16.92% and was characterized by FT-IR spectrophotometer and SEM-EDX. The composite materials were synthesized by blending urea as the active compound with composite material as the carrier compound. Three types of material were prepared: complete material (A), low-concentration Na-lignosulfonate material (B) and material without tapioca (C). The composite material had a spherical form with 0.79 mm radius and 2.16 mm swollen radius. Urea content inside material was 40.425 mg urea/g material. The urea diffusivity coefficient for material A, B, and C were 7.27 x 10–6; 15.50 x 10–6 and 0.94 x 10–6 m2 h–1, respectively. Modelling analysis showed the experiment obeyed around only 15% of the Korsmeyer–Peppas model, but there was good correlation (80%) with the unsteady-state diffusion model. Chemistry ; Sawdust ; Urea ; Composite number ; Diffusion ; Nuclear chemistry ; Thermal diffusivity ; Sodium alginate ; Lignin ; Chemical engineering ; Sodium ; Composite material ; Materials science ; Organic chemistry Synthesis and properties of polymers ; biodegradable polymer synthesis and properties ; Flame retardant materials and properties
Authors: Anurakshee Verma | Ufana Riaz
Source: Macromolecular Research (article, 2018-11-12)
Field: Materials Science — Polymers and Plastics

Synthesis, Characterization and in vitro Drug Release Studies of Sonolytically Intercalated Poly(o-anisidine)/Montmorillonite Nanocomposites Materials science ; Nanocomposite ; Montmorillonite ; Intercalation (chemistry) ; Polymerization ; Adsorption ; Nuclear chemistry ; Simulated body fluid ; In situ polymerization ; Chemical engineering ; Langmuir adsorption model ; Scanning electron microscope ; Polymer ; Organic chemistry ; Chemistry ; Composite material Conducting polymers and applications ; Polymer Nanocomposite Synthesis and Irradiation ; Synthesis and properties of polymers