jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Ahmed Elyamani | Oriol Caselles | Pere Roca | Jaime Clapés Boixader
Source: RECERCAT (Consorci de Serveis Universitaris de Catalunya) (article, 2018-01-31)
Field: Chemistry — Analytical Chemistry

Integrated Dynamic And Thermography Investigation Of Mallorca Cathedral An integrated investigation of engineering archaeometry was carried out using dynamic identification, dynamic monitoring and Infra-Red (IR) thermography for the study of the dynamic behavior of Mallorca cathedral in Spain. The cathedral is a large historical masonry structure built during 14-16th c. Dynamic identification and monitoring allowed the capturing of eight natural frequencies of the cathedral. IR thermography was used as a complementary inspection technique in the context of a continuous monitoring. Usually, IR thermography is used punctually for the inspection of a part of an inspected structure. Here an alternative was tried as the IR camera was installed for two two-weeks periods in the winter and in the summer of 2011 to monitor the stone surface temperature of a large portion of the cathedral. The correlation between the cathedral natural frequencies and the stone surface temperature of some selected structural elements was investigated and compared with the correlation with the external and the internal temperatures. It was found that the correlation with stone surface temperature was lower than that with external temperature. The study allowed a better understanding of the influence of temperature changes on the structure’s dynamic behavior. Thermography ; Materials science ; Geology ; Optics ; Physics ; Infrared Spectroscopy and Chemometric Analyses ; Essential Oils and Antimicrobial Activity
Authors: Anjana Talapatra | Shahin Boluki | Thien Duong | Xiaoning Qian | Edward R. Dougherty | Raymundo Arróyave
Source: arXiv (Cornell University) (preprint, 2018-03-14)
Field: Materials Science — Materials Chemistry

Towards an Autonomous Efficient Materials Discovery Framework: An Example of Optimal Experiment Design Under Model Uncertainty The accelerated exploration of the materials space in order to identify configurations with optimal properties is an ongoing challenge. Current paradigms are typically centered around the idea of performing this exploration through high-throughput experimentation/computation. Such approaches, however, do not account fo the always present constraints in resources available. Recently, this problem has been addressed by framing materials discovery as an optimal experiment design. This work augments earlier efforts by putting forward a framework that efficiently explores the materials design space not only accounting for resource constraints but also incorporating the notion of model uncertainty. The resulting approach combines Bayesian Model Averaging within Bayesian Optimization in order to realize a system capable of autonomously and adaptively learning not only the most promising regions in the materials space but also the models that most efficiently guide such exploration. The framework is demonstrated by efficiently exploring the MAX ternary carbide/nitride space through Density Functional Theory (DFT) calculations. Bayesian optimization ; Computer science ; Computation ; Framing (construction) ; Space (punctuation) ; Bayesian probability ; Bayesian inference ; Mathematical optimization ; Machine learning ; Artificial intelligence ; Algorithm ; Mathematics ; Engineering Machine Learning in Materials Science ; Semiconductor materials and devices ; Advanced Materials Characterization Techniques
Authors: Hyunseok Lee | Han-Seok Chae | Won-Seok Joo | Jongsoo Lee
Source: Journal of Computational Design and Engineering (article, 2018-03-14)
Field: Materials Science — Polymers and Plastics

Multi-objective design of thickness and curvature of a bendable structure considering delamination and strength characteristics Abstract The present study explores the finite element analysis and design optimization of a multi-layered bendable structure (i.e., a device of smart watch) considering delamination characteristics and materials strength conditions. The materials used for device and rubber in the smart watch are polycarbonate and thermoplastic polyurethane, respectively. Mooney-Rivlin model is employed to accommodate the hyperelastic behavior of rubber under large deformation. An evaluation of the delamination between layers and adhesive of the smart watch is conducted based on the cohesive zone model. The present study suggests the physical definitions of the vertical gap and sliding distance to describe the debonding/delamination properties in case of a bendable structure undergoing a large deformation. In the optimal design for the glass thickness, display thickness and radius of curvature, the bi-objective formal optimization is formulated to minimize both the vertical gap and sliding distance subjected to constraints on materials strength requirements of glass stress and display stress. The optimal design solutions are obtained using 2nd order polynomial based response surface models and a non-dominated sorting genetic algorithm (NSGA-II) in the context of multi-objective approximate optimization. In the optimization result, the sliding distance is improved by 25.64% with the secured stress limits compared to an initial design. The sliding distance value has been more enhanced under the contribution of the shear mode of delamination than the vertical gap under the normal mode. The study accommodates more enhanced design solutions to minimize debonding/delamination properties under strength requirements. Highlights This work conducts the design optimization of a multi-layered bendable structure (i.e., a smart watch). The delamination and materials strength requirements are considered. The delamination between layers and adhesive is performed based on the cohesive zone model. Vertical gap and sliding distance to represent delamination properties are suggested. The sliding distance is improved by 25.64% with the secured stress limits. Materials science ; Delamination (geology) ; Hyperelastic material ; Composite material ; Context (archaeology) ; Curvature ; Structural engineering ; Finite element method ; Deformation (meteorology) ; Engineering ; Geometry ; Mathematics Textile materials and evaluations ; Mechanical Behavior of Composites ; Additive Manufacturing and 3D Printing Technologies
Authors: Daniel Anavi | Yanay Popowski | Gadi Slor | M. Segal | Liat Frid | Roey J. Amir | Aviv Amirav | Elizabeth Amir
Source: Journal of Polymer Science Part A Polymer Chemistry (article, 2018-08-09)
Field: Materials Science — Biomaterials

Covalent functionalization of solid cellulose by divergent synthesis of chemically active dendrons ABSTRACT Covalent surface modification of solid cellulose with well‐defined and chemically reactive dendrons is introduced as a platform for cellulose grafting with functional materials. Surface functionalization with a first generation dendron is achieved by esterification employing bifunctional molecules based on 2,2‐bis(hydroxymethyl) propionic acid (bis‐MPA) under mild conditions and short reaction times. The activated cellulose surface displays hydrophobic properties and contains two reactive alkene end‐groups per graft, which are used for covalent binding to active agents, as demonstrated by selective functionalization of the modified cellulose with fluorescent dye via photopatterning. The number of active end‐groups on the surface of cellulose is multiplied by divergent solid‐state synthesis of second and third generation dendrons having four and eight reactive sites per dendron, respectively. The dendrons are assembled in only few hours by a sequence of thiol‐ene/esterification reactions. The ability to accurately control the number of binding sites on the surface of cellulose allows fine tuning of the surface properties, as shown by the attachment of hydrophobic small molecules to the dendronized cellulose. The first, second and third generation dendrons allow preparing surfaces with increasing hydrophobicities; second and third generation dendrons functionalized with small perfluoroalkyl molecule display superhydrophobic properties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56 , 2103–2114 Dendrimer ; Surface modification ; Cellulose ; Bifunctional ; Chemistry ; Covalent bond ; Polymer chemistry ; Chemical modification ; Molecule ; End-group ; Grafting ; Combinatorial chemistry ; Organic chemistry ; Polymer ; Polymerization Advanced Cellulose Research Studies ; Surface Modification and Superhydrophobicity ; Electrospun Nanofibers in Biomedical Applications
Authors: Zhenzhen Wang | Hui Cui | Zhimin Sun | Loı̈c M. Roch | Amanda N. Goldner | Hany F. Nour | Andrew C.‐H. Sue | Kim K. Baldridge | Mark A. Olson
Source: Soft Matter (article, 2018-01-01)
Field: Chemistry — Organic Chemistry

Melatonin-directed micellization: a case for tryptophan metabolites and their classical bioisosteres as templates for the self-assembly of bipyridinium-based supramolecular amphiphiles in water The bulk solution properties of amphiphilic formulations are derivative of their self-assembly into higher ordered supramolecular assemblies known as micelles and of their ordering at the air-water interface. Exerting control over the surface-active properties of amphiphiles and their propensity to aggregate in pure water is most often fine-tuned by covalent modification of their molecular structure. Nevertheless structural constraints which limit the performance of amphiphiles do emerge when trying to develop more sophisticated systems which undergo for example, shape-defined controlled assembly and/or respond to external stimuli. In this regard, the template-modulated assembly of the so-called "supramolecular amphiphiles" continues to make progress ordering molecules that otherwise have very little to no driving force to aggregate in a prescribed manner in aqueous solutions. Herein we describe the template-modulated micellization and ordering at the air-water interface of bipyridinium-based supramolecular amphiphiles triggered by host-guest interactions with high specificity for the neurotransmitter melatonin over its biosynthetic synthon l-tryptophan and the thermodynamic parameters governing the template-modulated micellization process. When bound to the bipyridinium units of micellized surfactant molecules, melatonin effectively serves as "molecular glue" capable of lowering the CMC by 52% as compared to untemplated solutions. Analysis of this system suggests that a hallmark of donor-acceptor template-modulated micellization in water is a strong positively correlated temperature dependence of the CMC and the absence of a U-shaped CMC-temperature curve. Our findings make a case for the incorporation of l-tryptophan-based metabolites and their classical synthetic pharmaceutical bioisosteres as potential targets/components of donor-acceptor CT-based supramolecular amphiphile systems/materials operating in water. Supramolecular chemistry ; Chemistry ; Tryptophan ; Melatonin ; Template ; Amphiphile ; Combinatorial chemistry ; Nanotechnology ; Organic chemistry ; Biochemistry ; Materials science ; Molecule ; Amino acid ; Biology ; Copolymer ; Neuroscience Surfactants and Colloidal Systems ; Molecular Sensors and Ion Detection ; Photochemistry and Electron Transfer Studies
Authors: E. Mahmoudpour | Shahrokh Hosseini-Hashemi | S. Ali Faghidian
Source: STRUCTURAL ENGINEERING AND MECHANICS (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

A nonlocal strain gradient theory for nonlinear free and forced vibration of embedded thick FG double layered nanoplates In the present research, an attempt is made to obtain a semi analytical solution for both nonlinear natural frequency and forced vibration of embedded functionally graded double layered nanoplates with all edges simply supported based on nonlocal strain gradient elasticity theory. The interaction of van der Waals forces between adjacent layers is included. For modeling surrounding elastic medium, the nonlinear Winkler-Pasternak foundation model is employed. The governing partial differential equations have been derived based on the Mindlin plate theory utilizing the von Karman strain-displacement relations. Subsequently, using the Galerkin method, the governing equations sets are reduced to nonlinear ordinary differential equations. The semi analytical solution of the nonlinear natural frequencies using the homotopy analysis method and the exact solution of the nonlinear forced vibration through the Harmonic Balance method are then established. The results show that the length scale parameters give nonlinearity of the hardening type in frequency response curve and the increase in material length scale parameter causes to increase in maximum response amplitude, whereas the increase in nonlocal parameter causes to decrease in maximum response amplitude. Increasing the material length scale parameter increases the width of unstable region in the frequency response curve. Nonlinear system ; Galerkin method ; Harmonic balance ; Vibration ; Mathematical analysis ; Length scale ; Homotopy analysis method ; Natural frequency ; Plate theory ; Mechanics ; Mathematics ; Amplitude ; Materials science ; Physics ; Boundary value problem ; Optics ; Acoustics Nonlocal and gradient elasticity in micro/nano structures ; Thermoelastic and Magnetoelastic Phenomena ; Composite Structure Analysis and Optimization
Authors: Ali Ahmadi | Aazam Ghassemi
Source: Physica E Low-dimensional Systems and Nanostructures (article, 2018-05-30)
Field: Materials Science — Materials Chemistry

Investigation both actions of elastic foundation parameters and small scale effect on axisymmetric bending of annular single-layered graphene sheet resting on an elastic medium Elasticity (physics) ; Graphene ; Stiffness ; Materials science ; Rotational symmetry ; Length scale ; Bending stiffness ; Mechanics ; Aspect ratio (aeronautics) ; Bending ; Parametric statistics ; Scale effects ; Scale (ratio) ; Composite material ; Nanotechnology ; Physics ; Mathematics Nonlocal and gradient elasticity in micro/nano structures ; Carbon Nanotubes in Composites ; Composite Material Mechanics
Authors: Ting-Ru Lin | Cheng‐Hua Lee | Yi-Chen Lan | Shruti Mendiratta | Long‐Li Lai | Jing‐Yun Wu | Kai‐Ming Chi | Kuang‐Lieh Lu
Source: Polymers (article, 2018-12-17)
Field: Chemistry — Inorganic Chemistry

Paddlewheel SBU based Zn MOFs: Syntheses, Structural Diversity, and CO2 Adsorption Properties Four Zn metal⁻organic frameworks (MOFs), {[Zn₂(2,6-ndc)₂(2-Pn)]·DMF}<i><sub>n</sub></i> (<b>1</b>), {[Zn₂(cca)₂(2-Pn)]·DMF}<i><sub>n</sub></i> (<b>2</b>), {[Zn₂(thdc)₂(2-Pn)]·3DMF}<i><sub>n</sub></i> (<b>3</b>), and {[Zn₂(1,4-ndc)₂(2-Pn)]·1.5DMF}<i><sub>n</sub></i> (<b>4</b>), were synthesized from zinc nitrate and <i>N</i>,<i>N</i>'-bis(pyridin-2-yl)benzene-1,4-diamine (2-Pn) with naphthalene-2,6-dicarboxylic acid (2,6-H₂ndc), 4-carboxycinnamic acid (H₂cca), 2,5-thiophenedicarboxylic acid (H₂thdc), and naphthalene-1,4-dicarboxylic acid (1,4-H₂ndc), respectively. MOFs <b>1</b>⁻<b>4</b> were all constructed from similar dinuclear paddlewheel {Zn₂(COO)₄} clusters and resulted in the formation of three kinds of uninodal 6-connected non-interpenetrated frameworks. MOFs <b>1</b> and <b>2</b> suit a topologic 4⁸·6⁷-net with 17.6% and 16.8% extra-framework voids, respectively, <b>3</b> adopts a pillared-layer open framework of 4⁸·6⁶·8-topology with sufficient free voids of 39.9%, and <b>4</b> features a <b>pcu</b>-type pillared-layer framework of 4<sup>12</sup>·6³-topology with sufficient free voids of 30.9%. CO₂ sorption studies exhibited typical reversible type I isotherms with CO₂ uptakes of 55.1, 84.6, and 64.3 cm³ g<sup>-1</sup> at 195 K and <i>P</i>/<i>P</i>₀ =1 for the activated materials <b>1'</b>, <b>2'</b>, and <b>4'</b>, respectively. The coverage-dependent isosteric heat of CO₂ adsorption (<i>Q<sub>st</sub></i>) gave commonly decreased <i>Q<sub>st</sub></i> traces with increasing CO₂ uptake for all the three materials and showed an adsorption enthalpy of 32.5 kJ mol<sup>-1</sup> for <b>1'</b>, 38.3 kJ mol<sup>-1</sup> for <b>2'</b>, and 23.5 kJ mol<sup>-1</sup> for <b>4'</b> at zero coverage. Adsorption ; Zinc nitrate ; Metal-organic framework ; Zinc ; Chemistry ; Naphthalene ; Sorption ; Benzene ; Enthalpy ; Crystallography ; Porosity ; Inorganic chemistry ; Topology (electrical circuits) ; Physical chemistry ; Organic chemistry ; Thermodynamics Metal-Organic Frameworks: Synthesis and Applications ; Carbon dioxide utilization in catalysis ; Covalent Organic Framework Applications
Authors: Shuo Tong | Mei‐Xiang Wang
Source: Synlett (article, 2018-11-15)
Field: Chemistry — Organic Chemistry

Catalytic Enantioselective Synthesis of 4-Amino-1,2,3,4-tetrahydropyridine Derivatives from Intramolecular Nucleophilic Addition Reaction of Tertiary Enamides A general and efficient method for the synthesis of highly enantiopure 4-amino-1,2,3,4-tetradydropyridine derivatives based on chiral phosphoric acid catalyzed intramolecular nucleophilic addition of tertiary enamides to imines has been developed. We have also demonstrated a substrate engineering strategy to significantly improve the enantioselectivity of asymmetric catalysis Enantiopure drug ; Chemistry ; Enantioselective synthesis ; Intramolecular force ; Nucleophile ; Catalysis ; Phosphoric acid ; Nucleophilic addition ; Combinatorial chemistry ; Organocatalysis ; Stereochemistry ; Organic chemistry Asymmetric Synthesis and Catalysis ; Synthesis and Catalytic Reactions ; Chemical Synthesis and Analysis
Authors: Michaël Smietana | Stellios Arseniyadis
Source: CHIMIA International Journal for Chemistry (article, 2018-09-01)
Field: Chemistry — Organic Chemistry

Challenges and Opportunities in DNA-based Asymmetric Catalysis The biological importance of nucleic acids for the storage, expression and regulation of genetic information is now well understood. By taming the chemical synthesis of these biomolecules, chemists have been able to engineer new architectures based on the ability of DNA and RNA to fold into secondary or even more complex tertiary structures with applications in medicinal chemistry, diagnostics or even material sciences. Exploiting the fascinating helical structure of DNA and RNA to develop new chiral bio-hybrid catalysts capable of promoting highly stereoselective transformations under mild and eco-compatible conditions is also an emerging area of research. In this short review, we report our recent results in the field of DNA-based asymmetric catalysis as well as the challenges and promising perspectives that lie in front of us. Nucleic acid ; Biomolecule ; DNA ; Nanotechnology ; RNA ; Chemistry ; Computational biology ; Catalysis ; Combinatorial chemistry ; Biology ; Materials science ; Biochemistry ; Gene Synthesis and Properties of Aromatic Compounds ; DNA and Nucleic Acid Chemistry ; Surface Chemistry and Catalysis
Authors: Bram Verbelen | Wim Dehaen | Koen Binnemans
Source: Synthesis (article, 2018-04-05)
Field: Chemistry — Organic Chemistry

Selective Substitution of POCl3 with Organometallic Reagents: Synthesis of Phosphinates and Phosphonates The selectivity of the substitution reaction of phosphoryl chloride with organometallic reagents was investigated using NMR spectroscopy. This led to the discovery that the selectivity of the substitution reaction can be tuned by choosing a proper organometallic reagent. A phosphinate could be obtained by using a Grignard reagent whereas an organozinc reagent provided a phosphonate. Based on these results, one-pot synthetic methods for the preparation of phosphinates and phosphonates using commercially available starting materials were developed. Both methods allow the synthesis of a broad range of either phosphinate or phosphonate derivatives in a straightforward and general procedure. Moreover, using these one-pot procedures, mixed systems substituted with different alkyl/aryl groups can be prepared. Chemistry ; Phosphinate ; Reagent ; Phosphonate ; Selectivity ; Aryl ; Alkyl ; Combinatorial chemistry ; Organic chemistry ; Substitution reaction ; Group 2 organometallic chemistry ; Chloride ; Medicinal chemistry ; Molecule ; Catalysis Organophosphorus compounds synthesis ; Phosphorus compounds and reactions ; Chemical Synthesis and Analysis
Authors: Patrick Laurén
Source: Työväentutkimus Vuosikirja (article, 2018-06-29)
Field: Materials Science — Biomaterials

Biomedical applications of nanofibrillar cellulose Hydrogels are emerging as an important source for current biomaterial design, as they often possess intrinsic physical and mechanical similarities with soft tissue, are non-toxic and biocompatible. However, many hydrogel-based biomimetic materials are either derived from limited sources, or require external activators to achieve functionality, such as chemical crosslinking or environmental cues. Furthermore, many cross-linkers used with hydrogels are toxic, and environmental cues invoke slow responses. Therefore, to function as a rational biomaterial design for a biomedical application, these properties are preferably avoided, or improved with a composite system containing two or more polymer components to overcome these limitations.\n\nPlant-derived nanofibrillar cellulose (NFC) possesses the same intrinsic properties as many other hydrogels derived from the components of extracellular matrices (ECM). Therefore, NFC shares the biocompatibility and non-toxicity aspects of biomimetic materials. However, additional features of NFC can be exploited, such as shear-thinning properties, spontaneous self-gelation and chemical modification capabilities. Additionally, the source of NFC is practically inexhaustible, and is environmentally biodegradable, bearing no ecological burden. Therefore, when designing hydrogel-based biomaterials, NFC offers versatility, which enables the fabrication of potential biomedical applications for various purposes in an environmentally safe way. \n\nIn this thesis, a wide range of potential applications of NFC-based hydrogels were investigated. These include 3D cell culturing, in vivo implantation and coating systems for drug and cell delivery, controlled drug delivery and local delivery as a bioadhesive system. These methods offer insight into the versatility of NFC-based hydrogels, which could improve the future design of biomaterials, for a safer and more efficient use in biomedical applications. Cellulose ; Polymer science ; Computer science ; Nanotechnology ; Materials science ; Chemistry ; Biochemistry Electrospun Nanofibers in Biomedical Applications ; Advanced Cellulose Research Studies ; Electrohydrodynamics and Fluid Dynamics