jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Koňáková Dana
Source: Cvut DSpace (Czech Technical University) (article, 2018-12-07)
Field: Materials Science — Ceramics and Composites

Thermal Resistance of Calcium Aluminate Cement Based Composites Building structures can be exposed to extreme conditions during their lifetime. One of these extreme situations is fire, or more precisely, exposure to extreme temperatures. In this case, there is a high likelihood of damage occurring to building materials, which could lead to the final collapse of a whole structure. Ordinary concrete, based on Portland cement, does not resist high temperatures very well; it is suitable for temperatures up to 400 °C. However, when exposed to higher temperatures decomposition of portlandite and dehydration of CSH gel will show. The aim of this thesis is to develop of such cement-based composites with better thermal resistance in regard to the application to structures with higher fire hazard i.e. boards for a tunnel lining or as face panel for improving thermal resistance. The first step was research into an optimization of material composition, which takes into account a choice of raw materials, their characterizations and setting of their amounts. For better thermal stability calcium, aluminate cement was chosen as a binder. The remaining components were basalt aggregate and basalt fibres; furthermore, the combination of different lengths of basalt fibres was investigated also. The second step was an assessment of a thermal resistance of these designed composites. This was performed by virtue of experimental measurement of physical properties. The particular characteristics of concrete were determined after being exposed to three different temperatures; specimens were pre-treated by three thermal loadings (105 °C, 400 °C, and 1000 °C). In the third part, the issue of optimal length fibres combination was investigated with the employment of similar approach of determining the residual properties. From the achieved results were concluded, that designed fibre reinforced, calcium alumina cement based composites with basalt aggregate proved its applicability in civil structures, and the optimal basalt fibres combination of longer: shorter fibres was found in the ratio of 90:10. Aluminate ; Composite material ; Materials science ; Cement ; Calcium ; Metallurgy Advanced ceramic materials synthesis ; Concrete and Cement Materials Research ; Nuclear materials and radiation effects
Authors: J. Brandão-Neto | Leonardo Bernasconi
Source: Crystals (article, 2018-06-29)
Field: Materials Science — Materials Chemistry

Electronic Excitations and Radiation Damage in Macromolecular Crystallography Macromolecular crystallography at cryogenic temperatures has so far provided the majority of the experimental evidence that underpins the determination of the atomic structures of proteins and other biomolecular assemblies by means of single crystal X-ray diffraction experiments. One of the core limitations of the current methods is that crystal samples degrade as they are subject to X-rays, and two broad groups of effects are observed: global and specific damage. While the currently successful approach is to operate outside the range where global damage is observed, specific damage is not well understood and may lead to poor interpretation of the chemistry and biology of the system under study. In this work, we present a phenomenological model in which specific damage is understood as the result of a single process, the steady excitation of crystal electrons caused by X-ray absorption, which acts as a trigger for the bulk effects that manifest themselves in the form of global damage and obscure the interpretation of chemical information from XFEL and synchrotron structural research. Radiation damage ; Synchrotron radiation ; Chemical physics ; Diffraction ; Crystal (programming language) ; Synchrotron ; Crystallography ; Excitation ; Macromolecule ; Electron ; Chemistry ; Materials science ; Nanotechnology ; Physics ; Radiation ; Optics ; Nuclear physics ; Computer science Enzyme Structure and Function ; Protein Structure and Dynamics ; X-ray Spectroscopy and Fluorescence Analysis
Authors: Muhammad Bashir Ibrahim | Ali Shihab Ahmed
Source: Bayero Journal of Pure and Applied Sciences (article, 2018-01-25)
Field: Chemistry — Analytical Chemistry

Adsorption of dyes onto activated watermelon (&lt;i&gt;Citrullus lanatus&lt;/i&gt;) rinds (AWR) Liquid phase adsorption experiments were conducted to study the removal of Methyl Orange (MO), and Rhodomine B (RB) dyes from aqueous solution using activated Watermelon rinds (AWR). The effect of adsorption parameters (pH, initial adsorbate concentrations time and temperature) were studied on the percentage of the dyes removal characterization of the adsorbent was achieved through infrared analysis (FTIR), microscope analysis (SEM) and potential of zero charge (pH theories were applied to the experimental data. The kinetic rates were modeled using the pseudo-first-order, pseudo-second order model with correlation coefficient (R the adsorption kinetics most effectively. Surface characterization of the adsorbent revealed that upon activation the cloudy and flaky nature of the raw rind tend to disappeared leading to higher surface area for adsor ascertained by the Potential charge of zero point. The results indicated a significant potential of the Activated Watermelon Rinds (AWR), a dyes removal from aqueous solution . Citrullus lanatus ; Adsorption ; Kinetics ; Chemistry ; Nuclear chemistry ; Horticulture ; Biology ; Organic chemistry ; Physics Dye analysis and toxicity ; Adsorption and biosorption for pollutant removal
Authors: Dhananjay Ipparthi | Tijmen Hageman | Nicolas Cambier | Metin Sitti | Marco Dorigo | Léon Abelmann | Massimo Mastrangeli
Source: Physical review. E (article, 2018-10-22)
Field: Materials Science — Biomaterials

Kinetics of orbitally shaken particles constrained to two dimensions We present an experimental study of the kinetics of orbitally-shaken, sliding macroscopic particles confined to a two-dimensional space bounded by walls. Discounting the forcing action of the external periodic actuation, the particles undergo a qualitative transition from a ballistic to a diffusive motion regime with time. Despite the deterministic input of kinetic energy provided by the shaker, the particles show translational velocities and diffusivity consistent with a confined random walk model. Such experimental system may therefore represent a suitable macroscopic analog to investigate aspects of molecular dynamics and self-assembly. Random walk ; Kinetics ; Kinetic energy ; Shaker ; Action (physics) ; Physics ; Statistical physics ; Thermal diffusivity ; Mechanics ; Classical mechanics ; Thermodynamics ; Mathematics Supramolecular Self-Assembly in Materials ; Advanced Materials and Mechanics ; Pickering emulsions and particle stabilization
Authors: Qi Yang | Fan Yang | Bing Gao | Mengzhuo Yang | Ammad Jadoon | Peng Yu | Jie Tian
Source: Energies (article, 2018-06-21)
Field: Materials Science — Materials Chemistry

Study on the Propagation Characteristics of Partial Discharge in Switchgear Based on Near-Field to Far-Field Transformation Ultra-high frequency (UHF) electromagnetic (EM) signals generated by the partial discharge (PD) process of high-voltage equipment are now widely used in PD detection. The computation of EM propagation generated by a local discharge source using a uniformly hardwiring source can hardly reveal the discharge characteristics. In this paper, a method of near-field to far-field transformation is proposed to realize the study of the propagation characteristics of the PD signal. A short gap discharge model is established to get the near-field electromagnetics and the proposed method is validated by comparing the directly calculated results with the results of the near-field source. In the end, a model of switchgear is employed to study the propagation characteristics of the EM signal based on the proposed method. Via numerical calculation, the influence of the equipment in the switchgear on the propagation of the discharge EM is studied. It is found that the direction of the discharge source has a significant effect on the distribution of the electric field, which indicates that the discharge source cannot be simplified to a uniformly hardwiring source. In addition, it is also obtained that the amplitude of the electric field shows the same trend with the growth of the discharge channel, which gives a method for evaluating the development of the PD. Particularly, the near-field to far-field transformation can provide an effective method for studying the propagation of discharge EM waves in large-scale equipment. Switchgear ; Partial discharge ; Acoustics ; Near and far field ; Field (mathematics) ; Electric field ; SIGNAL (programming language) ; Transformation (genetics) ; Electromagnetic field ; Electronic engineering ; Voltage ; Electrical engineering ; Physics ; Computer science ; Engineering ; Optics ; Mathematics High voltage insulation and dielectric phenomena ; Electrostatic Discharge in Electronics ; Lightning and Electromagnetic Phenomena
Authors: Cikra Ikhda Nur Hamidah Safitri | Ritmaleni Ritmaleni | Ning Rintiswati | Sardjiman Sardjiman | Takushi Kaneko
Source: Asian Journal of Pharmaceutical and Clinical Research (article, 2018-04-01)
Field: Chemistry — Organic Chemistry

EVALUATION OF BENZYLIDENE-ACETONE ANALOGUES OF CURCUMIN AS ANTITUBERCULOSIS Objective: The objective of this research is to evaluate the effect of benzylideneacetone analog of curcumin against Mycobacterium tuberculosis (MTB) H37Rv.Method: The activity of benzylideneacetone analog of curcumin is evaluated using mycobacteria growth indicator tube (MGIT) method and microplate alamar blue assay (MABA) method. The compound of minimum inhibitory concentration (MIC) is defined as the minimum concentration of drugs which really inhibit the growth of MTB.Result: The MIC compound of 1,5-bis(3,4-dichlorophenyl)-1,4-pentadiene-3-one (C9) and 1,5-bis(3-chlorophenyl)-1,4-pentadiene-3-one (C10) can inhibit the bacteria of MTB at the concentration of 500 μg/ml using MGIT method. Based on MABA method, it can be obtained similar MIC value of C9 compound and C10 compound that are 187.5 μg/ml.Conclusion: C9 and C10 have antituberculosis activity. Benzylideneacetone analog of curcumin which has chlor moiety has a better activity in inhibiting MTB, but it still needs further research to make it become a potent antituberculosis drug. Curcumin ; Moiety ; Mycobacterium tuberculosis ; Minimum inhibitory concentration ; Acetone ; Chemistry ; Isoniazid ; Pharmacology ; Combinatorial chemistry ; Stereochemistry ; Tuberculosis ; Biochemistry ; Medicine ; In vitro Multicomponent Synthesis of Heterocycles ; Synthesis and biological activity ; Synthesis of Tetrazole Derivatives
Authors: Pradeep Kundu | Tameshwer Nath | I. A. Palani | Bhupesh K. Lad
Source: Journal of Materials Engineering and Performance (article, 2018-06-04)
Field: Materials Science — Materials Chemistry

Integrating GLL-Weibull Distribution Within a Bayesian Framework for Life Prediction of Shape Memory Alloy Spring Undergoing Thermo-mechanical Fatigue Weibull distribution ; Materials science ; Spring (device) ; Bayesian probability ; Alloy ; Composite material ; Reliability engineering ; Structural engineering ; Mechanical engineering ; Forensic engineering ; Statistics ; Artificial intelligence ; Computer science ; Engineering ; Mathematics Shape Memory Alloy Transformations ; Topology Optimization in Engineering ; Microstructure and Mechanical Properties of Steels
Authors: John G. Michopoulos | Athanasios Iliopoulos | John C. Steuben | Virginia G. DeGiorgi
Source: Journal of Computing and Information Science in Engineering (article, 2018-02-14)
Field: Materials Science — Materials Chemistry

On the Multiphysics Modeling of Surface Aging Under Cathodic Protection In order to account and compensate for the dissipative processes contributing to the aging of cathodic surfaces protected by impressed current cathodic protection (ICCP) systems, it is necessary to develop the proper modeling and numerical infrastructure that can predict aging associated with quantities affecting the controller of these systems. In the present work, we describe various approaches for developing cathodic surface aging models (CSAMs) based on both data-driven and first principles-based methodologies. A computational ICCP framework is implemented in a manner that enables the simulation of the effects of cathodic aging in a manner that allows the utilization of various CSAMs that affect the relevant potentiodynamic polarization curves of the cathodic materials. An application of this framework demonstrates the capabilities of this system. We introduce a data-driven CSAM based on a loft-surface approximation, and in response to the limitations of this approach, we also formulate a first principles-based multiphysics and thermodynamic theory for aging. Furthermore, we discuss the design of a systematic experimental task for validating and calibrating this theory in the near future. Multiphysics ; Cathodic protection ; Dissipative system ; Computer science ; Mechanical engineering ; Finite element method ; Engineering ; Anode ; Structural engineering ; Physics ; Thermodynamics Corrosion Behavior and Inhibition ; Probabilistic and Robust Engineering Design ; Aluminum Alloy Microstructure Properties
Authors: Henry Bruhns | Marcus Wolff | Yannick Saalberg | K. Spohr
Source: Preprints.org (preprint, 2018-09-05)
Field: Chemistry — Spectroscopy

Quantitative Evaluation of Broadband Photoacoustic Spectroscopy in the Infrared With an Optical Parametric Oscillator Photoacoustic spectroscopy allows the identification of specific molecules in gases. We evaluate the spectral resolution and detection limits for a PAS system in the broadband infrared wavelength region 3270 nm ≲ &amp;lambda; ≲ 3530 nm driven by a continuous wave optical parametric oscillator with P &amp;asymp; 1.26 W by measuring the absorption of diluted propane, ethane and methane test gases at low concentrations c ~ 100 ppm for ~1350 discrete wavelengths &amp;lambda;i. The resulting spectra IPAS(&amp;lambda;i) were compared to the high resolution cross section data&amp;nbsp;&amp;sigma;FTIR obtained by Fourier Transform Infrared Spectroscopy from the HITRAN database. Deviations as little as 7.1(6)% for propane, 8.7(11)% for ethane and 15.0(14)% for methane with regard to the average uncertainty between&amp;nbsp;IPAS(&amp;lambda;i) and the expected reference values based on&amp;nbsp;&amp;sigma;FTIR were recorded. The wavelengths&amp;nbsp;&amp;lambda;res of the characteristic absorption lines can be pinpointed with a high relative accuracy &amp;lt;5 &amp;times; 10&amp;minus;5 corresponding to a resolution of &amp;lambda;res ~ 0.16 nm. Detection limits range between 7.1 ppb (ethane) to 13.6 ppb (methane) coinciding with high experimental signal-to-noise ratios. Moreover, using EUREQA, an artificial intelligence program, simulated mixed gas samples at low limits of detection could be deconvoluted. These results justify a further development of PAS technology to support, e.g., biomedical research. HITRAN ; Analytical Chemistry (journal) ; Spectroscopy ; Wavelength ; Fourier transform infrared spectroscopy ; Chemistry ; Photoacoustic spectroscopy ; Infrared ; Spectral line ; Optical parametric oscillator ; Methane ; Spectral resolution ; Detection limit ; Absorption spectroscopy ; Materials science ; Physics ; Optics ; Optoelectronics Spectroscopy and Laser Applications ; Photoacoustic and Ultrasonic Imaging ; Advanced Chemical Sensor Technologies
Authors: Paul N. Patrone | Andrew Dienstfrey
Source: Reviews in computational chemistry (preprint, 2018-10-19)
Field: Chemistry — Physical and Theoretical Chemistry

UNCERTAINTY QUANTIFICATION FOR MOLECULAR DYNAMICS The goals of this chapter are twofold. First, we wish to introduce molecular dynamics (MD) and uncertainty quantification (UQ) in a common setting in order to demonstrate how the latter can increase confidence in the former. In some cases, this discussion culminates in our providing practical, mathematical tools that can be used to answer the question, "is this simulation reliable?" However, many questions remain unanswered. Thus, a second goal of this work is to highlight open problems where progress would aid the larger community. Uncertainty quantification ; Computer science ; Dynamics (music) ; Molecular dynamics ; Management science ; Order (exchange) ; Data science ; Wish ; Epistemology ; Psychology ; Machine learning ; Sociology ; Engineering ; Chemistry ; Economics ; Philosophy Advanced Physical and Chemical Molecular Interactions ; Scientific Research and Discoveries ; Chemical and Physical Properties of Materials
Authors: Godwin Oghenewiroro Odu
Source: Journals & Books Hosting (International Knowledge Sharing Platform) (article, 2018-01-01)
Field: Materials Science — Materials Chemistry

Material Selection Optimization Using Weighted Sum Method and Team-Compromise Instrument The main challenge of multi-criteria optimization application is the difficulty in selecting the optimal material for any engineering product design.However, to determine criteria weights without conflicts among the team members is another problem being faced in concurrent engineering.In this paper weighted-sum method is adopted for solving material selection problems.The team-compromised approach is introduced as a parameter in the model by combining the subjective weights and objective weights of importance of the criteria in the decision making process.Two examples are presented to illustrate the efficacy of the model.The results shows that the proposed model is capable of selecting the best material taking into account the material selection criteria. Selection (genetic algorithm) ; Process (computing) ; Compromise ; Computer science ; Material selection ; Product (mathematics) ; Mathematical optimization ; Operations research ; Management science ; Industrial engineering ; Engineering ; Mathematics ; Artificial intelligence Material Selection and Properties ; Manufacturing Process and Optimization ; Ergonomics and Human Factors
Authors: Basuki Rahmat | H Amanda | Restina Bemis | A. Lisma | Y. Yusnaidar
Source: Jurnal Pendidikan IPA Indonesia (article, 2018-09-21)
Field: Chemistry — Physical and Theoretical Chemistry

Incomplete Explanation in Determining Oxidation Number: A Case Study on Chemistry Program Students The term â€œoxidation numberâ€ and related concept such as â€œelectronegativityâ€ and â€œformal chargeâ€ appear frequently in both elementary and advance chemistry text. However, it is evident from the literature (or textbooks) that these terms are often viewed to be synonymous. Incomplete explanation of the fundamental concept of oxidation number can lead that conclusions pertaining to such a misleading interpretation. This research was conducted to review the concepts from common used high school chemistry textbooks and these concepts were then transformed to 6 number open minded problems. These problems were then tested to 40 first semester chemistry program students in the University of Jambi who joining Basic Chemistry course. The result was about 80% of students give the right answer in determining oxidation number (problem number 1). But, in the certain molecule (problem number 2) they canâ€™t determine correctly because they couldnâ€™t use the â€œRuleâ€ from initial understanding in high school. For the next problem (4a), none of the students give the right oxidation number of an atom and all of them canâ€™t explain precisely correlation among oxidation number, electronegativity, and formal charge. The intent of this paper is to clarify the notion of oxidation number, electronegativity, and formal charge, describe their relationship (especially for high school chemistry textbooks), and criticize upon misleading application. Computer science ; Mathematics education ; Chemistry ; Psychology Various Chemistry Research Topics ; Science Education and Pedagogy
Authors: Carlos Sepúlveda | Oscar Montiel | José Manuel Cornejo‐Bravo | Roberto Sepúlveda
Source: Computational Intelligence and Neuroscience (article, 2018-11-01)
Field: Chemistry — Spectroscopy

Fuzzy Evaluation of Pharmacokinetic Models Population pharmacokinetic (PopPK) models allow researchers to predict and analyze drug behavior in a population of individuals and to quantify the different sources of variability among these individuals. In the development of PopPK models, the most frequently used method is the nonlinear mixed effect model (NLME). However, once the PopPK model has been developed, it is necessary to determine if the selected model is the best one of the developed models during the population pharmacokinetic study, and this sometimes becomes a multiple criteria decision making (MCDM) problem, and frequently, researchers use statistical evaluation criteria to choose the final PopPK model. The used evaluation criteria mentioned above entail big problems since the selection of the best model becomes susceptible to the human error mainly by misinterpretation of the results. To solve the previous problems, we introduce the development of a software robot that can automate the task of selecting the best PopPK model considering the knowledge of human expertise. The software robot is a fuzzy expert system that provides a method to systematically perform evaluations on a set of candidate PopPK models of commonly used statistical criteria. The presented results strengthen our hypothesis that the software robot can be successfully used to evaluate PopPK models ensuring the selection of the best PopPK model. Computer science ; Selection (genetic algorithm) ; Population ; Task (project management) ; Set (abstract data type) ; Multiple-criteria decision analysis ; Software ; Machine learning ; Medicine ; Artificial intelligence ; Operations research ; Mathematics Analytical Chemistry and Chromatography ; Analytical Methods in Pharmaceuticals ; Statistical Methods in Clinical Trials
Authors: Hadiqa Zafar | James T. Brewster | Christopher D. Wight | Matthew McVeigh | A. Steinbrück | Vincent M. Lynch | Jonathan L. Sessler
Source: Journal of Porphyrins and Phthalocyanines (article, 2018-12-04)
Field: Chemistry — Organic Chemistry

Synthesis of α,α’-linked penta- and septaheterocycles by tandem Suzuki coupling The controlled synthesis of oligoaromatics can provide materials of wide utility. Here, we describe the preparation of higher order oligoheterocycles via a tandem Suzuki cross-coupling protocol. This method has allowed for the iterative construction of fluorescent [Formula: see text],[Formula: see text]-linked penta- and septaheterocyclic systems with modification of the terminal moiety allowing for fine-tuning of the emission features. Tandem ; Chemistry ; Suzuki reaction ; Moiety ; Coupling (piping) ; Combinatorial chemistry ; Fluorescence ; Terminal (telecommunication) ; Stereochemistry ; Organic chemistry ; Computer science ; Palladium ; Telecommunications ; Catalysis Catalytic Cross-Coupling Reactions ; Radical Photochemical Reactions ; Oxidative Organic Chemistry Reactions