jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ferydon Babaei | Afroz Ghasemi
Source: Research Square (preprint, 2021-09-28)
Field: Materials Science — Materials Chemistry

Structural, Optical and Magnetic Properties of Nickel-Copper Ferrite NixCu1-xFe2O4 Copper ; Nickel ; Ferrite (magnet) ; Materials science ; Metallurgy ; Composite material Magnetic Properties and Synthesis of Ferrites ; Magneto-Optical Properties and Applications ; Multiferroics and related materials
Authors: Camille Blivet
Source: SPIRE - Sciences Po Institutional REpository (preprint, 2021-06-30)
Field: Materials Science — Polymers and Plastics

Limites de la méthodologie d'Arrhenius pour la prévision du vieillissement thermique de matériaux polymères utilisés en câblerie Cross-linked polyethylene and its copolymers (XLPE, XLEPR) are the most common insulating materials used in electrical cabling. During their use, these materials are submitted to thermal ageing phenomena. The thermo-oxidation of these materials causes a degradation of their properties, including mechanical properties. The aim of this work was to determine the limits of use of lifetime prediction methodologies, based on the Arrhenius law, of this type of materials. Different methodologies (end-of-life criterion, relative conversion rate, time/temperature superposition) were used to determine the activation energy of the thermo-oxidation reaction over a wide temperature range (50 – 160 °C). Breaks in the Arrhenius law were observed for both materials at low temperatures (50 – 70 °C), leading to considerable overestimations of the lifetime. As the physical state (semi-crystalline/amorphous) of the two materials is significantly different at these temperatures, the assumption of a unique influence of the physical state on the observed deviations has been rejected. It was also observed, for the stabilised formulations, that the addition of antioxidants was responsible for Arrhenius breaks, and this at different temperatures depending on the nature of the added antioxidant. This study thus warned of the danger of using Arrhenius-type methodologies to predict the durability of polymer materials. Arrhenius equation ; Polymer ; Materials science ; Thermal ; Ageing ; Composite material ; Engineering ; Engineering physics ; Forensic engineering ; Polymer science ; Thermodynamics ; Chemistry ; Physics ; Activation energy ; Physical chemistry ; Medicine Textile materials and evaluations
Authors: Hasan Kasım
Source: DergiPark (Istanbul University) (article, 2021-08-20)
Field: Materials Science — Polymers and Plastics

Investigation of the effect of carbon black and flame retardant agent on the fire properties of elastomer-based composite materials with high elongation capability Natural rubber-based composite mixtures (NRC) are widely used as commercial material in vehicle tires, shock absorbers, suspension system components, and various engineering applications due to their superior performance properties. In addition to the extremely severe conditions of the working environments of rubber-based materials, it also contains a serious fire safety problem. In this study, thermal, flame retardant and mechanical properties of rubber composite mixtures prepared with the addition of carbon black (CB) and intumescent flame retardant agents (IFR) with different particle sizes to be used as raw materials in air suspension systems were investigated. The effect of filler materials and flame retardants used on NRC was investigated using thermal analysis (TGA), combustion tests, mechanical tests, SEM, and microscopic studies. It was observed that the thermal stability and flammability of the composites depend on the network structure, the content, and the type of the additive in the mixture obtained. Particle size reduction has a significant role on reducing NRCs flammability while also increasing their mechanical properties. Fire retardant ; Carbon black ; Elastomer ; Composite number ; Elongation ; Materials science ; Composite material ; Carbon fibers ; Natural rubber ; Ultimate tensile strength Flame retardant materials and properties ; Material Properties and Applications ; Polymer Nanocomposites and Properties
Authors: Hasan Kasım
Source: Pamukkale University Journal of Engineering Sciences (article, 2021-01-01)
Field: Materials Science — Polymers and Plastics

Investigation of the effect of carbon black and flame retardant agent on the fire properties of elastomer-based composite materials with high elongation capability Doal kauuk esasl kompozit karmlar (NRC), sahip olduklar stn performans zellikleri sebebiyle ara lastiklerinde, amortisrlerde, sspansiyon sistem elemanlar ve eitli mhendislik uygulamalarnda bir tr ticari malzeme olarak yaygn bir ekilde kullanlmaktadr. Kauuk esasl malzemeler alt ortamlarda son derece ar artlara maruz kalmasnn yannda ciddi bir yangn gvenlii sorununu da bnyesinde barndrmaktadr. Bu almada, haval sspansiyon sistemlerinde hammadde olarak kullanlacak farkl partikl boyutlarna sahip karbon siyah (CB) ve alev ss ile reaksiyona girerek kabaran alev geciktirici ajanlarn (SRA) ilavesi ile hazrlanan kauuk kompozit karmlarnn termal, alev geciktirici ve mekanik zellikleri aratrlmtr Fire retardant ; Carbon black ; Elastomer ; Elongation ; Materials science ; Composite number ; Composite material ; Carbon fibers ; Natural rubber ; Ultimate tensile strength Flame retardant materials and properties ; Material Properties and Applications ; Polymer Nanocomposites and Properties
Authors: Elif Çalışkan Salihi | Selçuk TERZİ | Si̇nem Göktürk
Source: Deu Muhendislik Fakultesi Fen ve Muhendislik (article, 2021-05-24)
Field: Chemistry — Electrochemistry

Sulardan Vitamin Arıtımı: Nikotinik Asit Adsorpsiyonu Hem farmasötik endüstrisinin atık suları hem de evsel kullanım sonucu doğadaki su ortamlarına karışan biyomoleküllerden biri olan nikotinik asitin sulardan arıtılması insan ve çevre sağlığı üzerindeki olumsuz etkilerinden dolayı önem taşımaktadır. Bu sebeple bu çalışmada nikotinik asitin sulardan arıtılması maliyet ve kullanım açısından pek çok avantaj taşıyan adsorpsiyon yöntemi kullanılarak incelenmiştir. Adsorban olarak seçilen granüler ticari aktif karbonun nikotinik asiti sulu ortamdan uzaklaştırma etkinliği ve sıcaklık, pH gibi faktörlerin adsorpsiyon sürecine olan etkisi araştırılmıştır. Farklı başlangıç derişimlerindeki nikotinik asit çözeltileri kullanılarak çalkalama süresinin adsorpsiyon miktarı üzerindeki etkisi takip edilerek öncelikle adsorpsiyonun dengeye gelme süresi belirlenmiştir. Elde edilen kinetik veriler Lagergren 1. derece ve Yalancı 2. derece eşitlikleri ile modellenmiştir ve verilerin Lagergren 1. derece eşitliğine daha iyi uyduğu görülmüştür. Adsorpsiyon mekanizmasında tanecik içi difüzyonunun rol oynadığı ortaya koyulmuş ve hızı kontrol eden tek adımın tanecik içi difüzyon olmadığı anlaşılmıştır. Denge süresi boyunca yürütülen çalışmalardan elde edilen denge verileri ise Langmuir ve Freundlich izoterm eşitlikleri kullanılarak modellenmiş ve izoterm sabitleri hesaplanmıştır. Giles sınıflandırmasına göre L tipine uyduğu gözlemlenen nikotinik asit adsorpsiyonunun Langmuir denklemine daha iyi uyduğu tespit edilmiş ve adsorpsiyon kapasitesinin sıcaklığın düşmesi ile arttığı, ortamın pH değerinin değişmesinden ise önemli ölçüde etkilendiği tespit edilmiştir. Chemistry ; Molecular biology ; Physics ; Biology Electrochemical Analysis and Applications
Authors: Ekbal Mohammed Saeed Salih | Ahmed O. Al-Roubaiy | Yasser Louy Azeez Salih
Source: Annales de Chimie Science des Matériaux (article, 2021-02-28)
Field: Materials Science — Materials Chemistry

Analysis of the Influence of Hot Impacts on the Transformation of White Cast Iron Heat treatments are the most common method of transforming or modifying the structure of white cast iron. Cementite tapes can be decomposed at high temperatures and over a long period of time. These thermal treatments require special furnaces and a long period of time, as well as a high cost with major problems associated with these techniques. In this study, a mechanical thermal treatment was employed, which includes two basic stages, the first being heating at a certain temperature 1100℃ for a rather short period of time, then applying sequential strokes (one stroke or group of strokes) for a period not exceeding a few minutes. The findings proved that heating for short or long periods of time and at 1100℃ is not sufficient to get rid of cementite tapes, as the structure remained white cast iron. The important matter here is that the effect of the hot impact on the transformation of white cast iron into grey is related to the formation ratio. In this regard, the results uncover that using hot impact and at the same temperature, but at higher rates of forming (i.e., greater than 70%) the structure is completely transformed into grey cast iron. Cementite ; Cast iron ; Metallurgy ; Materials science ; Period (music) ; Transformation (genetics) ; White (mutation) ; Chemistry ; Microstructure ; Austenite Metal Alloys Wear and Properties ; Advanced machining processes and optimization ; Microstructure and Mechanical Properties of Steels
Authors: Ilona Pleşa | P. Notingher | Sandra Schlögl | Cristina Stancu | Andrea Johanna Wanner | Karin Wewerka | Philipp Marx | Frank Wiesbrock
Source: IEEE Access (article, 2021-01-01)
Field: Materials Science — Materials Chemistry

Structural Model for the Estimation of the Equivalent Permittivity of Nanodielectrics Based on Polyethylene and Epoxy Resins A structural model has been developed in order to calculate the equivalent permittivity of nanocomposites based on low-density polyethylene (LDPE) and epoxy resins (ERs) with inorganic fillers. It was assumed that each nanoparticle was centered in an interfacial region composed of three layers in the case of LDPE-based nanocomposites, and of two layers in the case of ER-based nanocomposites. The model for the estimation of the permittivity has been designed for flat samples of the height g, divided into cubes with the side-length l. Each of these cubes contains eight nanoparticles, which are separated from the polymer matrix by two or three layers. Based on the types and concentrations of dipoles present in the layers, the relative permittivity of each layer of the interface can be calculated. By the employment of a 3D numerical model in COMSOL, implemented by the finite element method associated with a cube, the distribution of the electric field inside a cube can be determined, which yields the values of the equivalent permittivity of the nanocomposites. In order to verify the numerical results, the permittivity of the nanocomposites based on LDPE and ERs with inorganic nanofillers (SiO2 or Al2O3) was determined in laboratory experiments. The results reveal congruent correlation between the computed and the experimentally determined values of the equivalent permittivity of the nanodielectrics. Permittivity ; Materials science ; Low-density polyethylene ; Composite material ; Nanocomposite ; Epoxy ; Relative permittivity ; Polyethylene ; Polymer ; Cube (algebra) ; Dielectric ; Geometry ; Mathematics ; Optoelectronics High voltage insulation and dielectric phenomena ; Dielectric materials and actuators ; Polymer Nanocomposites and Properties
Authors: Khoa Huynh | Annette Eva Jensen | Jonas Sundberg
Source: ChemRxiv (preprint, 2021-07-09)
Field: Chemistry — Analytical Chemistry

Extended characterization of petroleum aromatics using off-line LC-GC-MS Crude oil remains a grand challenge for analytical chemists. With the advent of multi-dimensional chromatography and high-resolution mass spectrometry, an impressive number of compounds have been identified. However, the large diversity in structure and abundance makes it difficult to obtain full compound coverage in a single analysis. Sample preparation methods such as solid-phase extraction and SARA-type analysis reduces this complexity. However, the molecular diversity within each fraction is still highly complex. Thus, in the routine analysis, only a small part of the chemical space is typically characterized. Obtaining a more detailed composition of crude oil is important for production, processing and environmental aspects. We have developed a high-resolution fractionation method for isolation and preconcentration of trace aromatics, including oxygenated and nitrogen-containing species. By the isolation of the more abundant aromatics, i.e. monoaromatics and naphthalenes, trace species can be enriched for analysis. This enables the identification of features not detectable by routine methods. We demonstrate the applicability by fractionation and subsequent GC-MS analysis of 14 crude oils sourced from the North Sea. The number of tentatively identified compounds increased by approximately 60 to 150% compared to solid-phase extraction and GC×GC-MS. Furthermore, the method was used to successfully isolate and identify a new set of heteroatom-containing aromatics (amines, ketones). The method is not intended to replace traditional sample preparation techniques or multi-dimensional chromatography but acts as a complementary tool. An in-depth comparison to routine characterization techniques is presented concerning advantages and disadvantages. Fractionation ; Fraction (chemistry) ; Chromatography ; Chemistry ; Mass spectrometry ; Sample preparation ; Gas chromatography ; Resolution (logic) ; Gas chromatography–mass spectrometry ; Characterization (materials science) ; Solid phase extraction ; Extraction (chemistry) ; Computer science ; Materials science ; Nanotechnology Petroleum Processing and Analysis ; Analytical Chemistry and Chromatography ; Mass Spectrometry Techniques and Applications
Authors: Maxwell Li
Source: Deep Blue (University of Michigan) (article, 2021-01-01)
Field: Chemistry — Spectroscopy

Advancement of Micro Gas Chromatographs and Their Core Components The development of portable vapor sensors is of high interest for in situ and real-time chemical analysis. These sensors are targeted at industrial and environmental monitoring as well as point-of-care applications. Advances in microelectromechanical systems (MEMS) technologies has allowed for the miniaturization of benchtop gas chromatography (GC) into portable micro GC (µGC) systems that allow for field analysis. This dissertation details the development of critical µGC components, especially microcolumns and micro photoionization detectors (PIDs), along with their assembly into prototype µGC systems for in situ testing. Two different microcolumn coatings were developed to broaden the range of chemical separations suitable for µGC analysis, including a micro porous layer open tubular column for light compound analysis and micro ionic liquid column for simultaneous analysis of polar and nonpolar compounds. A new column coating method was also demonstrated to improve separation performance without the need for increasing column length or any auxiliary components. A micro helium desorption PID (µHDPID) fabrication process was developed to allow for the robust fabrication of universal vapor detectors, complementing the increased range of separations from the new microcolumn coatings. A high sensitivity PID system was also developed with sub-pg detection limits, comparable to or even surpassing that of benchtop flame ionization detectors. These components were assembled into two prototype systems, one for hydrogen and methane detection for breath analysis, and another ultracompact µGC system with the entire system capable of being contained within a 1.1 L box, including batteries, pumps, and electronic readout boards. Together, these developments are aimed at increasing the range of applications that can be targeted by µGC by broadening its separation and detection capabilities, as well as improving the sensing performance. Core (optical fiber) ; Gas chromatography ; Chromatography ; Environmental science ; Process engineering ; Mathematics ; Chemistry ; Materials science ; Engineering ; Composite material Analytical Chemistry and Chromatography
Authors: Timur V. Fadeev | М. В. Дорохин | Yu. M. Kuznetsov | Lyudmila I. Kveglis | Vladimir V. Shevchuk
Source: Journal of Siberian Federal University Mathematics & Physics (article, 2021-02-01)
Field: Materials Science — Materials Chemistry

Steel 110G13L. Thermomagnetic and Galvanomagnetic Effects in its Films The article shows the ability to control magnetic properties due to modulation of phases in the film with varying temperature of growth. So, at low growth temperatures, a film is formed with an axis of easy magnetization in plane. An increase in temperature leads to a change in the phase composition of the film. It is shown that the presence of even a small component of the magnetization vector in the perpendicular direction leads to the appearance of a thermomagnetic effect of a large magnitude with respect to thermal noise Thermomagnetic convection ; Magnetization ; Condensed matter physics ; Materials science ; Perpendicular ; Phase (matter) ; Thermal ; Plane (geometry) ; Physics ; Magnetic field ; Thermodynamics ; Geometry ; Mathematics Material Properties and Failure Mechanisms ; Stonefly species taxonomy and ecology ; Diverse Industrial Engineering Technologies
Authors: Pierre Wüthrich | Jun Jin Choong | Shinya Yuki
Source:  (preprint, 2021-09-13)
Field: Materials Science — Materials Chemistry

InFrag: Using Attribution-based Explainability to Guide Deep Molecular Optimization The recently proposed Genetic expert guided learning (GEGL) framework has demonstrated impressive performances on several \textit{de novo} molecular design tasks. Despite the displayed state-of-the art results, the proposed system relies on an expert-designed Genetic expert. Although hand-crafted experts allow to navigate the chemical space efficiently, designing such experts requires a significant amount of effort and might contain inherent biases which can potentially slow down convergence or even lead to sub-optimal solutions. In this research, we propose a novel genetic expert named \textit{InFrag} which is free of design rules and can generate new molecules by combining promising molecular fragments. Fragments are obtained by using an additional graph convolutional neural network which computes attributions for each atom for a given molecule. Molecular substructures which contribute positively to the task score are kept and combined to propose novel molecules. We experimentally demonstrate that, within the GEGL framework, our proposed attribution-based genetic expert is either competitive or outperforms the original expert-designed genetic expert on goal-directed optimization tasks. When limiting the number of optimization rounds to one and three rounds, a performance increase of approximately 43% and 20% respectively is observed compared to the baseline genetic expert. Furthermore, we empirically show that combining several experts that share a fixed sampling budget at each optimization round generally improves or maintains the overall performance of the framework. Computer science ; Task (project management) ; Machine learning ; Artificial intelligence ; Expert system ; Convergence (economics) ; Graph ; Chemical space ; Genetic algorithm ; Data mining ; Theoretical computer science ; Bioinformatics ; Drug discovery ; Biology ; Engineering Machine Learning in Materials Science ; Computational Drug Discovery Methods ; Machine Learning and Data Classification
Authors: Anne Xu
Source: SPIRE - Sciences Po Institutional REpository (preprint, 2021-03-26)
Field: Materials Science — Materials Chemistry

Impact de la distribution des antioxydants sur la stabilisation des isolants PE de câbles électriques de centrale nucléaire Crosslinked low density polyethylene (XLPE) is commonly used for electrical cables insulation in nuclear power plants. However, as any hydrocarbon polymer, XLPE is sensitive to oxidation, which is the main cause of the polymer degradation. In order to protect polymers against oxidation, antioxidants (AO) are systematically added in their formulation. However, due to their difference in polarity, AO generally show a low solubility in polyethylene (PE) matrix, which can easily lead to a phase separation of AO. In such case, the behaviour of the excessive AO is yet to be studied. The objective of this thesis was, hence, to elucidate the AO distribution in a PE matrix, according to the incorporated concentration; and to study the impact of such distribution on the polymer stabilisation. To do so, two types of AO commonly used in industry were studied: a hindered phenol and a thiodipropionate. An experimental methodology was established, enabling the detection, identification and quantification of the different AO phase present in the polymer. Using this methodology, a phase separation was observed for an AO concentration of about 0.9 wt%, above which the excessive AO are exuded and recrystallized onto the material surface. Through the thermal ageing study in air of model samples stabilised with an excess, or not, of AO, the chemical consumption and physical loss mechanisms of the different AO phase were investigated; and the role of initially in excess AO on the stabilisation of the polymer during its oxidative ageing was studied. The continuation of the study on an industrial material (electrical cable) then allowed to evaluate the consequences of the AO phase separation in the polymer on the material dielectric properties. Nuclear power ; Electrical engineering ; Distribution (mathematics) ; Nuclear engineering ; Materials science ; Power (physics) ; Engineering ; Automotive engineering ; Composite material ; Environmental science ; Mechanical engineering ; Physics ; Nuclear physics ; Mathematics High voltage insulation and dielectric phenomena ; Electrical Fault Detection and Protection ; Power Transformer Diagnostics and Insulation
Authors: Kaneez Fatima | Shaukat Khalid | Imran Ahmed | Kiran Qadeer | Nudrat Fatima | Hina Yasin | Rana Asif Hussain | Iqbal Ahmad
Source: RADS Journal of Pharmacy and Pharmaceutical Sciences (article, 2021-06-25)
Field: Chemistry — Analytical Chemistry

Phytopharmacognostic Evaluation and Fourier Transform Infrared Fingerprint in the Quality Control of Various Culinary Herbs: AN ULTIMATE REMEDY IN ASIA Background: The quality and efficacy of culinary herbs commonly practiced in Asia as a remedy for seasonal illnesses such as cold, flu, congestion, fever and inflammation, etc. The extemporaneous preparations of these culinary herbs are being formulated as traditional practice either in the form of extract, decoction, and paste etc. These culinary herbs are being practiced for curing sporadic illnesses since ancient time.&#x0D; Objectives: In present study five herbs’ i.e. Elettaria cardamomum (cardamom), Cinnamomum zeylanicum (cinnamon), Carum carvi (caraway), Oreganum vulgare (oregano) and Syzygium aromaticum (clove) have been obtained from the market to assure quality of herbs in local market.&#x0D; Methodology: Various quality control tests including microscopic evaluation, physico-chemical characteristics, Thin layer chromatography (TLC) and Fourier Transform Infrared spectroscopy (FTIR) have been performed to determine their compliance with the standards. The TLC has been used for the identification of the active ingredients on comparison of their Rf values with the reference standard. FTIR Spectra of these materials have been obtained to identify and confirm structural information and assignment of functional groups.&#x0D; Results: Many of the herbal samples used in this study have been complied with the available official standards as given in Pharmacopoeia. If the samples did not comply with the standards then it indicates that the sample belongs to spurious quality of raw herb, which is the prime cause that may interfere with the therapeutic efficacy and variability of outcomes.&#x0D; Conclusion: This study help to provide a significant data to herbal drug manufacturers for authentication of commercially available herbs which may be used in the formulation of extemporaneous or commercially available herbal medicine. Traditional medicine ; Herb ; Medicine ; Quality assessment ; Medicinal herbs ; Mathematics Heavy Metals in Plants ; Ethnobotanical and Medicinal Plants Studies