jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: Antoine Durocher | Gilles Bourque | Jeffrey M. Bergthorson
Source:  (article, 2022-06-13)
Field: Materials Science — Materials Chemistry

Bayesian Calibration of Kinetic Parameters in the CH Chemistry Towards Accurate Prompt-NO Modelling Abstract Significant efforts made by the gas turbine industry have helped reduce nitrogen oxides (NOx) emissions considerably. To meet and surpass the increasingly stringent regulations, accurate and robust thermochemical mechanisms are needed to help design future sub-10 ppm combustion systems. Uncertainty in kinetic modelling, however, can result in large prediction uncertainty and significant discrepancy between models that hinder the identification of promising combustors with confidence. Direct reaction rate measurements are seldom available for some reactions, especially when involving short-lived radicals like methylidyne, CH. As the main precursor to the prompt-NO formation pathway, its large parametric uncertainty directly propagates through the nitrogen chemistry preventing accurate and precise emissions predictions. Recent independent CH concentration measurements obtained at various operating conditions are used as indirect rate measurements to perform statistical, or Bayesian, calibration. A subset of important reactions in the CH chemistry affecting peak-CH concentration is identified through uncertainty-weighted sensitivity analysis to first constrain the parametric space of this prompt-NO precursor. Spectral expansion provides the surrogate model used in the Markov-Chain Monte Carlo method to evaluate the posterior kinetic distribution. The resulting constrained CH-chemistry better captures experimental measurements while providing smaller prediction uncertainty of a similar order as the uncertainty of the measurements, which can increase the confidence in simulation results to identify promising future low-emissions configurations. For the quasi-steady state species CH, fuel decomposition reactions leading to CH production are constrained while little impact is observed for intermediate reactions within the CH-chemistry. The reduction in prediction uncertainty results mainly from the constrained correlations between parameters which greatly limit the set of feasible reaction rate combinations. Additional independent direct and indirect measurements would be necessary to further constrain rate parameters in the CH chemistry, but this calibration demonstrates that predictions of radical species can be improved by assimilating enough data. Combustion ; Calibration ; Parametric statistics ; Uncertainty analysis ; Uncertainty quantification ; Monte Carlo method ; Chemistry ; Computer science ; Statistical physics ; Physics ; Mathematics ; Simulation ; Physical chemistry ; Machine learning ; Statistics Catalytic Processes in Materials Science ; Atmospheric chemistry and aerosols ; Vehicle emissions and performance
Authors: Soumyashree S. Panda | Ravi S. Hegde
Source:  (article, 2022-03-04)
Field: Materials Science — Electronic, Optical and Magnetic Materials

A learning-based approach for metasurface design beyond the unit-cell approximation State-of-the-art nanofabrication permits the realization of highly aligned multi-layered metasurfaces with high lateral resolution and wide areas. The exploitation of the vast degrees of freedom and material choice is hampered by the difficulty in the inverse design of metasurfaces. The prevalent design approach of unit-cell library creation and element juxtaposition is known to result in reduced efficiency owing to the inaccurate accounting of inter-element coupling. We report on our recent efforts in accelerated evolutionary optimization for designing metasurfaces with extended unit-cells using learned surrogate models. The difficulty in creating learned models with acceptable predictive capacity in higher dimensional parameter spaces arises from the need for extensive ground-truth generation. By a systematic study of network architectures and dataset sampling strategies, we uncover efficient ground-truth generation strategies. Specifically, we consider 2 and 3-nanoellipse titania metaatoms allowing full control over the elliptical parameters and with an optical response consisting of the spectral behavior of various transmission and reflection-mode diffracted orders for proof-of-concept demonstration. The systematic investigation reveals that densely connected neural architecture and judicious sampling strategies can allow learned model creation even with smaller ground-truth datasets. Computer science ; Ground truth ; Realization (probability) ; Reflection (computer programming) ; Sampling (signal processing) ; Inverse ; Degrees of freedom (physics and chemistry) ; Coupling (piping) ; Computer engineering ; Proof of concept ; Artificial intelligence ; Theoretical computer science ; Physics ; Computer vision ; Mathematics Metamaterials and Metasurfaces Applications ; Animal Vocal Communication and Behavior ; Photonic Crystals and Applications
Authors: Aaron S. Yeardley | Robert A. Milton | Peyman Z. Moghadam | Joan Cordiner | Solomon Brown
Source: Process Safety and Environmental Protection (article, 2022-02-04)
Field: Chemistry — Inorganic Chemistry

Active subsets as a tool for structural characterisation and selection of metal-organic frameworks To date over 80,000 metal-organic framework (MOF) structures have been synthesised and only ca. 3% of these have had their adsorption capabilities measured for storing oxygen alone. As such, in order to aid the process of producing top-performing MOFs for storing various gases, accurate methods to predict the deliverable capacity of MOFs that have their synthesis method already known is increasingly important. For this purpose, this paper develops a reduced order model (ROM) that can predict the deliverable capacity of synthesised MOFs irrespective to the storage gas across similar gases. The ROM is constructed by identifying the active subspaces through a Sobol’ index-based global sensitivity analysis (GSA). The resulting Gaussian process (GP) regression model efficiently predicts the deliverable capacity given a MOFs pore properties with this reduced dimensional space. This approach was applied to a practical MOF exploration example by training a ROM with 2745 MOFs storing methane at 30 bar. The ROM was robustly tested and analysed before using it to predict the deliverable capacity of 82,221 synthesised MOFs storing oxygen at 30 bar. To ensure validity in the exploration example, the predictions produced from the methane trained ROM were compared to a separate ROM trained using the same MOFs but storing oxygen gas. The methane trained ROM was found to be in agreement with the oxygen trained ROM, and was shown to be a viable tool to identify the top-performing MOF structures for oxygen storage. Deliverable ; Metal-organic framework ; Methane ; Computer science ; Process engineering ; Materials science ; Adsorption ; Chemistry ; Engineering ; Systems engineering ; Organic chemistry Metal-Organic Frameworks: Synthesis and Applications ; Machine Learning in Materials Science ; X-ray Diffraction in Crystallography
Authors: Ruiping Li | Nitsan Barel | Vasudevan Subramaniyan | Françoise Tibika | Roy E. Hoffman | Yuri Tulchinsky
Source: ChemRxiv (preprint, 2022-11-23)
Field: Chemistry — Organic Chemistry

Sulfonium-Pincer Ligands Flexibility in Pt(II) Complexes The coordination chemistry of sulfonium cations, dormant since the early eighties, was recently revived when we reported the synthesis and characterization of the first Rh(I) and Pt(II) pincer sulfonium complexes. With the Pt(II) complexes, we had noticed the hemilability of our sulfonium pincer ligands, further explored here. This hemilability led to mononuclear bidentate complexes with both the aromatic and aliphatic sulfonium ligands. With the latter, due to its flexibility, dimeric structures of two different kinds were also allowed. The more rigid aromatic backbone adopted only a mononuclear bidentate mode, leading to a dynamic equilibrium between two asymmetric geometries. Computational study of this process predicted a local energy minimum for a pincer sulfonium-PtCl complex. However, the activation energy of its formation, as a possible intermediate, was found to be too high and indeed was not observed experimentally. Nevertheless, such PtCl complex was prepared and characterized by XRD. Although its S-Pt bond was significantly shorter than in its PtMe analog, the former was easily dissociated in coordinating solvents. It seems that lowering the dz2 orbital in this complex by strong π-back donation, renders the Pt(II) nucleus more susceptible to nucleophilic attacks. This comprehensive study should lay the ground for future applications of pincer sulfonium-Pt(II) complexes in π-acid catalysis. Pincer movement ; Sulfonium ; Chemistry ; Denticity ; Nucleophile ; Stereochemistry ; Catalysis ; Medicinal chemistry ; Crystallography ; Organic chemistry ; Salt (chemistry) ; Crystal structure Catalytic Alkyne Reactions ; Sulfur-Based Synthesis Techniques ; Cyclopropane Reaction Mechanisms
Authors: Kairi Masuda
Source: ChemRxiv (preprint, 2022-08-30)
Field: Materials Science — Materials Chemistry

Phase-field modelling of molecular dynamics with diffusive motions Recently, phase-field modelling has been expanded to the molecular scale. However, such atomistic phase-field simulation cannot treat diffusive motions of molecules so far. Here, we modify phase-field modelling of molecular dynamics to include rigid body motions by employing quaternions and smooth random functions. This modelling successfully reproduces translational and rotational diffusive motions of a molecule. This study further expands the applications of atomic-scale phase-field modelling. Quaternion ; Molecular dynamics ; Field (mathematics) ; Phase (matter) ; Force field (fiction) ; Statistical physics ; Scale (ratio) ; Physics ; Dynamics (music) ; Classical mechanics ; Mathematics ; Geometry ; Quantum mechanics Crystallization and Solubility Studies ; Solidification and crystal growth phenomena ; Protein Structure and Dynamics
Authors: Haikal Mustafa | Munirah Onn | Aznilinda Zainudin | Norin Hafizah Rahim
Source: International Journal of Academic Research in Progressive Education and Development (article, 2022-01-04)
Field: Chemistry — Physical and Theoretical Chemistry

Ball and Stick Fun Model Kit for Stem Education The majority of students are expected to have strong critical thinking and problem-solving abilities in 21st-century learning. Students can form mental habits that will help them succeed in any subject due to the emphasis on logical thought processes and problem-solving. The list of science, technology, Engineering, and mathematics (STEM) subjects is quite vast and chemistry is one of them. The STEM curriculum pushes students to think critically and develop original answers. Chemistry subject is believed as a major subject in the science field, however, in Malaysia, it is also deemed as one of the most challenging subjects. Crystal and chemical bonding topic are included in the Sijil Pelajaran Malaysia (SPM), Sijil Tinggi Persekolahan Malaysia (STPM), Diploma and Degree syllabus. In chemistry, the topic of crystal structure and chemical bonding is commonly taught via slide presentations explaining the theories. Thus, this kit introduces a new teaching method where students need to produce the chemical bonding or crystal structure by using the “Ball and Stick” model. The coloured balls made from styrofoam represent atoms, while a set of sticks represent the bonds that hold them together. It is a special set of tinker kits to represent how molecules look. This kit box has been sold at a fixed price of RM19.90 and it contains 200 pieces of molecular model kit, including 70 atoms (ball), 100 bonds (stick) and 30 parts for lone pair. It comes with CD-ROM for instruction, notes and exercises hence providing a fun learning tool kit for students from secondary to university level. The kits can be dismantled and rebuilt or can be used for display or as a model for teaching specific crystallographic or structural concepts. The different coloured balls represent atoms of different elements. A survey has been conducted on a small group of diploma students and 100% of students agree that this kit is both entertaining and useful in gaining insight into the subject matter. Syllabus ; Mathematics education ; Curriculum ; Subject (documents) ; Set (abstract data type) ; Chemistry ; Mathematics ; Computer science ; Psychology ; Pedagogy ; Library science Various Chemistry Research Topics
Authors: Xingsheng Sun
Source: arXiv (Cornell University) (preprint, 2022-07-22)
Field: Materials Science — Biomaterials

Uncertainty Quantification of Material Properties in Ballistic Impact of Magnesium Alloys The design and development of cutting-edge light materials for extreme conditions including high-speed impact remains a continuing and significant challenge in spite of steady advances. Magnesium (Mg) and its alloys have gained much attention, due to their high strength-to-weight ratio and potential of further improvements in material properties such as strength and ductility. In this paper, we adopt a recently developed computational framework to quantify the effects of material uncertainties on the ballistic performance of Mg alloys. The framework is able to determine the largest deviation in the performance measure resulting from a finite variation in the corresponding material properties. It can also provide rigorous upper bounds on the probability of failure using known information about uncertainties and the system, and then conservative safety design and certification can be achieved. We specifically focus on AZ31B Mg alloys, and assume that the material is well-characterized by the Johnson-Cook constitutive and failure models, but the model parameters are uncertain. We determine the ordering of uncertainty contributions for model parameters and the corresponding behavior regimes where those parameters play a crucial role. Finally, we show that how this ordering provides insight on the improvement of ballistic performance and the development of new material models for Mg alloys. Ductility (Earth science) ; Materials science ; Material properties ; Enhanced Data Rates for GSM Evolution ; Ballistic impact ; Measure (data warehouse) ; Magnesium ; Computer science ; Structural engineering ; Projectile ; Composite material ; Metallurgy ; Engineering ; Creep Magnesium Alloys: Properties and Applications ; High-Velocity Impact and Material Behavior ; Metal Forming Simulation Techniques
Authors: Jake Song | Niels Holten‐Andersen | Gareth H. McKinley
Source: arXiv (Cornell University) (preprint, 2022-11-11)
Field: Materials Science — Materials Chemistry

Non-Maxwellian viscoelastic stress relaxations in soft matter Viscoelastic stress relaxation is a basic characteristic of soft matter systems such as colloids, gels, and biological networks. Although the Maxwell model of linear viscoelasticity provides a classical description of stress relaxation, the Maxwell model is often not sufficient for capturing the complex relaxation dynamics of soft matter. In this Tutorial, we introduce and dis-cuss the physics of non-Maxwellian linear stress relaxation as observed in soft materials, the ascribed origins of this effect in different systems, and appropriate models that can be used to capture this relaxation behavior. We provide a basic toolkit that can assist the understanding and modeling of the mechanical relaxation of soft materials for diverse applications. Viscoelasticity ; Soft matter ; Stress relaxation ; Relaxation (psychology) ; Soft materials ; Stress (linguistics) ; Statistical physics ; Physics ; Classical mechanics ; Mechanics ; Materials science ; Colloid ; Thermodynamics ; Nanotechnology ; Chemistry ; Physical chemistry ; Philosophy Material Dynamics and Properties
Authors: Amanda E. Schivell
Source: CourseSource (article, 2022-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Electron Location, Location, Location: Understanding Biological Interactions Introductory Biology courses typically introduce the structure and function of biomolecules such as proteins and nucleic acids. To understand biomolecules fully, students require knowledge of fundamental chemistry concepts such as covalent bonding, intermolecular interactions and hydrophilicity/hydrophobicity (1).&nbsp;Students enter our large (&gt;400 student) course with a notoriously limited conceptual grasp of basic chemistry principles.&nbsp;Our lesson is an activity designed on the principles of POGIL (<a href="https://pogil.org/">Process Oriented Guided Inquiry Learning</a>).&nbsp;In 50 minutes, students build their own definitions of the following: polar vs. non-polar covalent bonds, hydrophilicity/hydrophobicity and the nature of hydrogen bonding based simply on the relative electronegativities of oxygen, nitrogen, carbon and hydrogen.&nbsp;We find that this exercise improves students&rsquo; understanding of these chemical concepts. Since adopting this activity, students have been better able to understand biomolecular structures and predict interactions between molecules. <em>Primary image:</em>&nbsp;Hydrogen Bond.&nbsp;Possible hydrogen bond interaction that can form between two simple organic molecules. Biomolecule ; Electronegativity ; Hydrogen bond ; Chemistry ; Molecule ; Covalent bond ; GRASP ; Chemical bond ; Nanotechnology ; Chemical physics ; Intermolecular force ; Non-covalent interactions ; Computational chemistry ; Organic chemistry ; Computer science ; Materials science Various Chemistry Research Topics
Authors: Joshua P. Gray
Source: CourseSource (article, 2022-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

Pick Your Poison: A Semester-Long Case Study for Undergraduate Toxicology The ability to collate information from diverse scientific resources and effectively employ scientific writing is an essential skill for scientists. This lesson describes a semester-long project entitled &ldquo;Pick Your Poison,&rdquo; which is designed for use in a one-semester Toxicology course. Students are each assigned to or choose their own individual toxicant as a case study from a pre-selected list of toxicants (poisons) that align with the theme of the course. As content is covered in the course, students complete ten scaffolded, low-stakes writing modules that are shared with groupmates of 4&ndash;5 students. Each module covers a major feature of the toxicant, such as chemical features, characteristics of absorption, distribution, metabolism, and elimination (ADME), and organ-specific toxicities. Students share their work with their group mates and the instructor, peer review one another&rsquo;s work, and then edit their original post as appropriate to produce a concise, 3&ndash;4 paragraph product. At the end of the course, students compile their writing modules into an article in the format of the Encyclopedia of Toxicology. This project can be adapted to any toxicology course through alteration of the content and number of modules and/or the type of final deliverable. Several evidence-based and inclusive teaching practices are included, such as writing-to-learn, peer review, and low-stakes assessments. <em>Primary Image:</em>&nbsp;A picture of the online discussions for two of the ten modules. Paragraph ; Troubleshooting ; Mathematics education ; Computer science ; Medical education ; Psychology ; World Wide Web ; Medicine Various Chemistry Research Topics
Authors: Angus Fotherby | Harold J. Bradbury | Jennifer L. Druhan | Alexandra V. Turchyn
Source:  (preprint, 2022-10-04)
Field: Chemistry — Inorganic Chemistry

Supplementary material to "An emulation-based approach for interrogating reactive transport models" Figure S1: An example decision tree, in which for an input of (x=0.7,y=0.6) traversing the tree returns z=3. Emulation ; Computer science ; Economics Radioactive element chemistry and processing
Authors: Bryanna Rupprecht | John Pierce Wise | Mindy Reynolds
Source: CourseSource (article, 2022-01-01)
Field: Chemistry — Physical and Theoretical Chemistry

A Case Study for Teaching Toxicology: Using Whales as an Indicator for Environmental Health One of the challenges of teaching scientific courses is helping students understand research methods, biological models, and data analysis, which can be especially difficult in classes without a laboratory component. Within the field of toxicology, it is also important for students to understand how living organisms are affected by exposure to toxicants and how these toxicants can impact the ecosystem. Resources focusing on active learning pedagogy are scarce in the field of toxicology compared to other disciplines. In this activity, upper-level students in an introductory toxicology course learn to interpret data from primary literature, draw conclusions about how toxicants, specifically metals, can impact susceptible populations, and understand the One Environmental Health approach. Students work in small groups to answer questions concerning data from a paper and then share their responses with the entire class building their communication skills. The instructor serves as a moderator, allowing the students to work through concepts, intervening only when necessary. This approach enables a deeper level of understanding of content and allows the students to engage actively in the learning process. As such, students think critically through relevant problems and find connections to the real world. This lesson can be adapted for several levels of students and could be modified depending on the objectives of the course. Class (philosophy) ; Moderation ; Process (computing) ; Psychology ; Field (mathematics) ; Mathematics education ; Computer science ; Social psychology Various Chemistry Research Topics ; Science Education and Pedagogy
Authors: Tuğçe Günter | Sibel Kılınç Alpat | Özge Özbayrak Azman
Source: Batı anadolu eğitim bilimleri dergisi (article, 2022-10-26)
Field: Chemistry — Physical and Theoretical Chemistry

Laboratuvar Uygulamalarında Çöktürme Titrasyonları Konulu Senaryoların Etkisi Araştırmada Genel Kimya III (Analitik Kimya) dersi “Çöktürme Titrasyonları” konusunda örnek-olaya dayalı laboratuvar uygulamalarının öğrencilerin akademik başarılarına etkisinin incelenmesi amaçlanmıştır. Çalışma grubunu bir üniversitenin Fen Bilgisi Öğretmenliği Programında okuyan ikinci sınıf öğrencileri oluşturmaktadır. Mevcut iki şubeden birisi deney (n=32), diğeri kontrol grubu (n=32) olarak rastgele seçilmiştir. Araştırma ön-test son-test kontrol gruplu yarı-deneysel desendir. Deney grubu öğrencileri örnek-olaya dayalı laboratuvar uygulamalarıyla, kontrol grubu öğrencileri ise öğretim programına uygun laboratuvar uygulamalarıyla dersi işlemiştir. Araştırmada çöktürme titrasyonları konusunda günlük yaşamla ilişkili iki örnek olay geliştirilmiştir. İlk örnek olayın konusu, havuz dezenfeksiyonunda aşırı klor gazının kullanımından dolayı zehirlenen bir gence, ikinci örnek olayın konusu ise tatlı su balığının deniz suyuna bırakılması sonucu balığın başına gelenlerin anlatılmasına dayanmaktadır. 11 Açık uçlu sorudan oluşan “Çöktürme Titrasyonları Başarı Testi” veri toplama aracı olarak kullanılmıştır. Testteki açık uçlu sorulara verilen yanıtlar puanlanarak nicel veriler elde edilmiş ve bağımsız ve bağımlı gruplar için t-testi ile analiz edilmiştir. Açık uçlu sorular ayrıca içerik analiziyle analiz edilmiştir. Çalışma sonuçları, örnek-olaya dayalı laboratuvar uygulamalarının öğrencilerin çöktürme titrasyonları (arjantometrik yöntemler) konusunda tam anlamalarını ve akademik başarılarını arttırdığını göstermiştir. Physics ; Mathematics ; Humanities ; Gynecology ; Chemistry ; Philosophy ; Medicine Various Chemistry Research Topics