jablonkagroup/rise_ai_scientists huggingface dataset:
Authors: John R. Tumbleston
Source: Carolina Digital Repository (University of North Carolina at Chapel Hill) (article, 2019-08-08)
Field: Materials Science — Polymers and Plastics

Photonics and transport in bulk heterojunction organic solar cells In this thesis, the groundwork is established for a new type of bulk heterojunction (BHJ) organic solar cell geometry that has photonic crystal (PC) photoactive layers. This design is motivated by the need to improve light absorption without increasing active layer thickness, which for many BHJ systems, degrades electrical performance. It is demonstrated that with the right choice of materials and cell dimensions, quasiguided or resonant modes are excited near the band edge of a variety of BHJ blends to enhance absorption. Resonant modes are predicted by first developing a scattering matrix optical model and then observed in wavelength-, polarization-, and angular-dependent reflection and photocurrent measurements. PC cells are fabricated using a facile nanopatterning technique, where highly ordered arrays of submicron features are constructed over large areas in a single step. Optical and electrical function of this new cell architecture is fully explored in this thesis. Through optical measurements and modeling, PC devices show clear enhancements in light absorption. On the other hand, the impact of the nonplanar geometry on electrical performance is not as easily deduced due to the multitude of electrical processes that lead to photocurrent generation. First, the electrical properties of the electron transporting layer that interfaces with the BHJ nanopattern and provides optical contrast in the PC greatly affect parasitic resistances in the solar cell. By including resistance losses in a drift/diffusion numerical model that describes electrical performance, it is shown that these losses greatly influence fundamental steps leading to photocurrent generation. This is confirmed with experiment by comparing two BHJ material systems that have different affinities for exciton separation. Second, significant levels of free carrier recombination are predicted by the electro-optical model due to the relatively long transport paths in the nanopattern features. To test this prediction, an experimental technique is developed to measure the transport lengths of photogenerated electrons and holes in BHJ solar cells. It is found that transport lengths of positive and negative carriers are mismatched and helps explain both PC electrical performance and recent conflicting results of planar BHJ solar cells in the literature. Photonics ; Organic solar cell ; Optoelectronics ; Materials science ; Engineering physics ; Photovoltaic system ; Physics ; Engineering ; Electrical engineering Conducting polymers and applications ; Silicon and Solar Cell Technologies ; Organic Electronics and Photovoltaics
Authors: Lauren M. Browning
Source: ODU Digital Commons (Old Dominion University) (article, 2019-05-09)
Field: Materials Science — Materials Chemistry

New Tools for Real-Time Study of Embryonic Development Embryonic development represents one of the most complex and dynamic cellular processes in biology, and plays vital roles in understanding of functions of embryonic stem cells (ESCs) and design of ESC-based therapy. Conventional assays and fluorescence-based imaging methods have been widely used for the study of embryonic development. These conventional methods cannot effectively provide spatial and temporal resolutions with sufficient sensitivity and selectivity that are required to depict embryonic development in vivo in real-time at single-cell and single-molecule resolutions. In this dissertation, we have developed a wide range of innovative tools for real-time study of embryonic development. These new tools include biocompatible and photostable plasmonic gold (Au) and silver (Ag) nanoparticle (NP) imaging probes, dark-field optical microscopy and spectroscopy (DFOMS), and ultrashort electric pulses. We have designed and synthesized a mini-library of Au and Ag NPs with different sizes and chemical properties. We have used developing zebrafish embryos as in vivomodel organisms to study embryonic development and as in vivo assays to study size- and chemical-dependent nanotoxicity. We found that these multicolored imaging probes can passively diffuse into embryos and enter into embryos non-invasively. These NPs exhibit superior photostability and enable us to study embryonic environments for a desired period of time. They can be illuminated under a standard microscope halogen lamp and characterized simultaneously using DFOMS equipped with a multi-spectral imaging system to achieve real-time multiplexing imaging. Our studies show that Au NPs are much more biocompatible than Ag NPs, while Ag NPs are much more sensitive and colorful than Au NPs. Notably, we can make Ag NPs nearly as biocompatible as Au NPs by functionalizing their surfaces with biocompatible peptides. Furthermore, Ag NPs can incite stage-specific embryonic phenotypes, and enable us to generate distinctive mutants for further identification of biomarkers for better understanding of embryonic development and for potential diagnosis of birth defects. We have developed new methods to effectively culture and sustain ESCs of zebrafish, mouse and human, laying down the foundation for real-time study of differentiation of ESCs both in vitro and in vivo for a wide variety of biomedical applications. Embryonic stem cell ; Nanotechnology ; Nanotoxicology ; Live cell imaging ; Zebrafish ; Embryogenesis ; Microscopy ; Materials science ; Fluorescence microscope ; Microscope ; Biophysics ; Chemistry ; Nanoparticle ; Fluorescence ; Cell biology ; Biology ; Embryo ; Optics ; Physics ; Cell Nanoparticles: synthesis and applications ; Advanced biosensing and bioanalysis techniques ; Advanced Nanomaterials in Catalysis
Authors: Wenqin Shi
Source: Research Repository (Delft University of Technology) (article, 2019-01-21)
Field: Materials Science — Materials Chemistry

Positron Annihilation Studies on Thin Film Solar Cells: CdSe and PbSe Quantum Dot Thin Films and Cu(In1-xGax)Se2 Layered Systems High efficiency, low cost, and long stability are three key factors for the wide application of photovoltaics (PV) which are currently intensively studied in order to meet the increasing global renewable energy demand. Currently, the PV market is mainly based on silicon. However, solar cells based on silicon may not be capable to meet the long-term global energy demand due to their relatively high costs and high energy required for the synthesis of silicon wafers, opening the door to conventional thin films (such as Cu(In1-xGax)Se2 (CIGS)) and innovative thin films (e.g. semiconductor quantum dots (QDs), based on PbS, PbSe, CdSe QDs). The advantages of QDs as solar cell materials are the low-temperature synthesis process, the tunable band gap via control of the composition and size, and the promise of physical mechanisms that may increase efficiency above the Shockley-Queisser limit, such as multiple exciton generation (MEG), in which more than one exciton is created from a single photon. However, the low efficiency, with a current laboratory record just above 10%, and the durability are still limitations on their widespread application in the PV market. It is very important to understand the surface structure and surface-ligand interactions in order to improve the efficiency and stability of QD solar cells. For CIGS solar cells, research-cell efficiencies have reached 22.6%, which is just below the efficiencies of Si-based solar cells. Besides, various deposition approaches have been developed that can supply high-efficiency, low-cost and large-area solar cell devices. However, it is still a challenge to guarantee long-term stability of CIGS modules. CIGS solar cells can be well protected by sealing into glass plates, but this in turn increases the manufacturing cost. Therefore, understanding of the degradation mechanism is necessary.&lt;br/&gt;Positron techniques are powerful tools to study the surface composition of QDs and to determine the types of open space deficiencies in thin film materials. For QDs, previous studies provided indications that positrons can trap and annihilate at the surfaces of semiconductor QDs and can effectively probe the surface composition and electronic structure of colloidal semiconductor QDs. For CIGS, previous depth-sensitive positron experiments indicated the sensitivity of positrons to probe the types of vacancy-related defects in CIGS. Copper indium gallium selenide solar cells ; Quantum dot ; Optoelectronics ; Photovoltaics ; Materials science ; Quantum dot solar cell ; Multiple exciton generation ; Thin film ; Photovoltaic system ; Wafer ; Solar cell ; Cadmium telluride photovoltaics ; Quantum efficiency ; Nanotechnology ; Silicon ; Semiconductor ; Polymer solar cell ; Electrical engineering Quantum Dots Synthesis And Properties ; Chalcogenide Semiconductor Thin Films ; Advanced Photocatalysis Techniques
Authors: Irina Remkunas | Igor Donskoy | А. Н. Козлов
Source: E3S Web of Conferences (article, 2019-01-01)
Field: Materials Science — Materials Chemistry

Development of method for determination of the kinetics constants of coal char gasification in pore diffusion regimes In this paper, we developed a method for determining the kinetic constants of partially diffusion-controlled heterogeneous reactions in a porous sample of powder. Studies have been conducted on the experimental data of thermogravimetric analysis of carbon conversion in a stream of CO 2 , using a new method of processing kinetic curves, to obtain updated values of the kinetic constants under conditions where widely used models are inappropriate. Data obtained can be used for a reliable assessment of the characteristics of the gasification process. Char ; Diffusion ; Thermogravimetric analysis ; Kinetic energy ; Kinetics ; Materials science ; Thermodynamics ; Coal ; Porosity ; Reaction rate constant ; Diffusion process ; Chemistry ; Computer science ; Organic chemistry ; Composite material ; Physics Thermal and Kinetic Analysis ; Thermochemical Biomass Conversion Processes ; Coal Combustion and Slurry Processing
Authors: Jean Baptiste Bike Mbah | Richard Kamga | Mirela Praisler | D Criste Rodica.
Source: Journal of Materials Science and Engineering B (article, 2019-06-28)
Field: Chemistry — Organic Chemistry

Effect of Texture and Surface Chemistry of Palm Nut Hull Activated Carbon on the Adsorption of Pigments and Free Fatty Acids from Vegetable Oils Activated carbons were produced from palm nut hull, which is a waste material of palm oil extraction industries. Activated carbons having various pore size distributions and surface composition were obtained by conventional carbonization method via the sulphuric acid solution pre-treatment method. The surface areas, mesopore volume and -OH groups of activated carbons increase with the increases of sulphuric acid solution concentration. The activated carbons obtained were tested for the adsorption of pigments and free fatty acids from palm oil and shea butter. It comes out from this study that the amount of adsorbate (i.e. pigments and free fatty acids) fixed increases with the increase of the adsorption temperature and with the increases of mesopore volume. Intraparticle diffusion, pseudo-first-order and pseudo-second-order kinetics models were used to analyze the kinetics data obtained at different temperatures (temperature range 60 C to 90 C). Among the kinetics models used, the pseudo-second order was the best applicable model to describe the adsorption of oil pigments and free fatty acid onto activated carbons. The activation energies obtained by applying the Arrhenius equation for the adsorption of pigments were low (i.e. less than 40 kJmol -1 for the both vegetables oils), indicating that the adsorption could be assigned to physisorption. Adsorption ; Nut ; Chemistry ; Activated carbon ; Food science ; Texture (cosmology) ; Palm oil ; Pigment ; Hull ; Carbon number ; Botany ; Organic chemistry ; Chemical engineering ; Materials science ; Biology ; Composite material ; Computer science Edible Oils Quality and Analysis
Authors: DONG Li-Jia | Guo Xiao-Jie | Xue Li | Chaogui Chen | Jin Yang | Ahmed Alsaedi | Tasawar Hayat | Qingzhou Zhao | Sheng Guo-dong
Source: Journal of Inorganic Materials (article, 2019-01-01)
Field: Chemistry — Electrochemistry

Microscopic Insights into pH-dependent Adsorption of Cd(II) on Molybdenum Disulfide Nanosheets Herein, the retention mechanisms and microstructure of Cd(II) on MoS 2 nanosheets were evaluated by batch experiments and EXAFS technology.The sorption of Cd(II) on MoS 2 was strongly affected by solution pH, contact time, and temperature, but not by the ionic strength.The solution pH could only promote the sorption capacity, but does not improve the sorption rates and change the sorption isotherms and thermodynamics in the pH range of 3.3-9.6.The pseudo-second-order model could fit the equilibrium data better and the intra-particle diffusion model showed three typical stages in the sorption process.The isotherms and thermodynamics analysis indicated that the heterogeneity sorption of Cd(II) onto MoS 2 was a spontaneous, endothermic, and irreversible process.The EXAFS spectra revealed the coexistence of two sorption types.The inner-sphere complexation was formed in the form of Cd-S bond at lower pH (3.56, 6.48), while the Cd(OH) 2 precipitation occurred in the form of Cd-O and Cd-Cd bonds at higher pH (9.57).These results provide new insights into the interaction mechanisms between metal ions and MoS 2 nanosheets. Molybdenum disulfide ; Materials science ; Molybdenum ; Adsorption ; Disulfide bond ; Chemical engineering ; Inorganic chemistry ; Nanotechnology ; Metallurgy ; Organic chemistry ; Chemistry ; Biochemistry Electrochemical Analysis and Applications
Authors: Ashish Kumar Shukla | Rajendra Kumar
Source: International Journal of Research in Advent Technology (article, 2019-06-10)
Field: Materials Science — Materials Chemistry

Modeling of Monomer Pressure Evolution in an Inductively Coupled pulsed plasma deposition of aniline A model has been developed to predict the evolution of monomer pressure over time in an inductively coupled plasma reactor. The model proposes a two-step deposition mechanism: dissociation of monomer by electron collisions fast and . subsequent slow diffusion of radicals toward the substrate. A free radical mechanism is proposed and the dissociation rate . constant is calculated based on the best available cross section information. The model uses an analogous electrical circuit to predict preplasma gas flow conditions. Based on the monomer pressure model, a relationship between pressure prior to electrical discharge and the corresponding plasma polymerized acetylene deposition rate was measured experimentally. A plot of measured deposition rate versus preplasma monomer pressure was observed to have a relative maximum. Aniline ; Plasma ; Inductively coupled plasma ; Monomer ; Deposition (geology) ; Materials science ; Inductively coupled plasma mass spectrometry ; Analytical Chemistry (journal) ; Chemistry ; Environmental chemistry ; Chromatography ; Polymer ; Organic chemistry ; Mass spectrometry ; Physics ; Geology ; Composite material ; Nuclear physics Diamond and Carbon-based Materials Research ; Plasma Diagnostics and Applications ; Metal and Thin Film Mechanics
Authors: Lalia Foud | Abeer A. Emam | Asmaa M. Gamal | M.M. Ibrahim | Mona Seif
Source: International Journal of Development (article, 2019-12-10)
Field: Materials Science — Materials Chemistry

Amelioration of mesoporous surface by varying concentration of ZnO to eliminate Methylene blue: characterization, kinetics modules and thermal parameter Adsorption assessment of ZnO-SiO2 (ZSnc) by UV/Vis spectro-photometery was used to monitor the removal of the cationic dye (MB)from waste waters. Silica nanoparticles with a high adsorption capacitywere prepared by sol-gel method. SiO2 modification was done bydissolving various ratios of zinc oxides at 10%, 30%, 50%, 70% and 90%.With a view to explain the adsorptive characteristics, they were portrayed by XRD, TEM, EDX, SEM, N2adsorption/desorption isotherms techniques and FT-IR. The results showed that anamorphous shape and porous structure were obtained by the sol-gel method. The calcination time of nanomaterial and concentration of MB have a significant effect on the adsorption efficiency. The equilibrium data were evaluated using the Langmuir and Freundlich isotherms in order to determine the best adjustment to the experimental data. Langmuir model has been the most appropriate for fitting the experimental data. Additionally, the adsorption kinetics is best described by the pseudo-second order model at a different concentration. Values demonstrated that the adsorption process is exothermic, spontaneous, and favorable. The results elucidated the potential for a new utilize of mesostructured nanomaterial as an active adsorbent. Methylene blue ; Characterization (materials science) ; Mesoporous material ; Kinetics ; Materials science ; Thermal ; Chemical engineering ; Nuclear chemistry ; Chemistry ; Nanotechnology ; Thermodynamics ; Organic chemistry ; Catalysis ; Physics ; Engineering Silicone and Siloxane Chemistry ; Pigment Synthesis and Properties
Authors: Sunil T. Galatage
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2019-03-05)
Field: Materials Science — Materials Chemistry

DEVELOPMENT AND CHARACTERIZATION OF MICROPARTICLES OF RAZATRIPTAN BENZOATE DRUG CARRIER SYSTEM VIA NASAL ROUTE Objective: Rizatriptan Benzoate is the 5H1 receptor agonist and used in treatment of migraine, cluster headache. The main objective is to develop ideal anti-migraine nasal mucoadhesive microparticles as local and systemic drug delivery system. Method: An attempt was made to formulate the nasal mucoadhesive microparticle of Rizatriptan Benzoate with excipients like mucoadhesive polymers i.e HPMC, ethyl cellulose etc., by using modified solvent evaporation method. And evaluated them for production yield, drug loading efficiency, surface morphology by SEM, drug content, particle size, <em>In-vitro</em> drug release studies. The release rates were studied using GRAPHPAD PRISM software. Result and discussion: The prepared microparticles of Rizatriptan Benzoateformulations were found to be satisfactory particle size i.e in the range of 36.96 to 53.28µm,mucoadhesion time of F5 found to be 370 min,drug content was found to be72.86 % to 81.80 % and drug release of the drug follow zero order kinetic model. Optimized formulation F5shows that the developed formulations have shown improved dissolution profile in comparison to other formulation.The developed nasal mucoadhesive microparticles are having potential to deliver of anti-migraine drugs via nasal route. Drug ; Chemistry ; Characterization (materials science) ; Drug delivery ; Nanotechnology ; Materials science ; Medicine ; Pharmacology Advanced Nanomaterials in Catalysis ; Diverse Scientific Research Studies ; Pigment Synthesis and Properties
Authors: K. Ziat and M. Saidi N. El Bardiji
Source: Zenodo (CERN European Organization for Nuclear Research) (article, 2019-11-15)
Field: Chemistry — Organic Chemistry

ADSORPTION OF COPPER FROM AQUEOUS SOLUTION BY MOROCCAN ATTAPULGITE: KINETIC AND THERMODYNAMIC STUDIES In this paper, Moroccan treated attapulgite (MTATP) was used as a mineral adsorbent for removal of copper ions from aqueous solution. Fourier transform infrared spectroscopy (FTIR) was used to study the functional groups of attapulgite. Kinetic analysis of the experimental results was carried out by using the pseudo-first-order, pseudo-second-order and the intraparticle diffusion models. The modeling results showed that the pseudo-second-order model is able to describe the adsorption behavior of copper onto attapulgite more accurately. Thermodynamic parameters such as Gibbs free energy (∆G?), the enthalpy (∆H?) and the entropy change (∆S?) of sorption were calculated. Outcomes reveals that the sorption process is spontaneous and exothermic Adsorption ; Aqueous solution ; Copper ; Kinetic energy ; Chemistry ; Physical chemistry ; Organic chemistry ; Physics Edible Oils Quality and Analysis ; Food Chemistry and Fat Analysis ; Freezing and Crystallization Processes
Authors: Yosuke Katsumura
Source: RADIOISOTOPES (article, 2019-04-14)
Field: Materials Science — Materials Chemistry

3.1 HIMAC Facility in Radiation Chemistry—Radiation Sources Relevant to the Studies on LET Effects— 1898年にP. CurieとM. CurieがRaを発見して以来，放射線化学では多種の放射線源が開発され，多くの放射線誘起効果について研究が進められた。本稿では，これまでの水溶液の放射線化学におけるLET効果研究に関連して，歴史的に使用されてきた放射線源としての放射性同位体，加速器，原子炉，さらに他の放射線施設の変遷を簡単にレビューする。最後に，放射線化学におけるこれまでと将来のHIMAC施設の重要性と寄与について議論する。 Curie ; Marie curie ; Radiochemistry ; Radiobiology ; Medical physics ; Radiation ; Nuclear medicine ; Medicine ; Physics ; Chemistry ; Nuclear physics ; Curie temperature ; Irradiation ; Business ; Condensed matter physics Lanthanide and Transition Metal Complexes ; Radioactive element chemistry and processing ; Luminescence Properties of Advanced Materials
Authors: Joshua Troy Hatton
Source: UND Scholarly Commons (University of North Dakota) (article, 2019-01-01)
Field: Materials Science — Polymers and Plastics

Determination of Sorption Characteristics of Wood Using a New Non-Fickian Empirical Model Wood is a versatile and cost-effective building material found in everyday life. However, it has a disadvantage of readily absorbing both water vapor from the surrounding air and liquid water when in direct contact. The absorption of water increases the rate of the wood decaying and can also affect the physical properties, such as warping and swelling. Previous research has looked into defining the rate of absorption by modeling it based on Fick’s second law. Fick’s second law bases the rate of absorption on a diffusion coefficient; a constant that changes with time. Herein, a new empirical model is proposed that has constants that stay fixed with time as a way to avoid using diffusion coefficients. Furthermore, the empirical model’s validity will be examined for water vapor and the effect of paint coatings, liquid water at different wood densities and temperature, and the application of the model to organic solvents. Sorption ; Constant (computer programming) ; Fick's laws of diffusion ; Environmental science ; Thermodynamics ; Chemistry ; Diffusion ; Computer science ; Physics ; Adsorption ; Physical chemistry Textile materials and evaluations ; Forest ecology and management ; Wood Treatment and Properties
Authors: Nadeau Eric | Metzger Donald
Source: NCSU Libraries Repository (North Carolina State University Libraries) (article, 2019-08-04)
Field: Materials Science — Materials Chemistry

Coupled Protium and Deuterium Diffusion Model for Prediction of Hydrogen Isotope Distributions in Zr-Nb Pressure Tubes Deuterium ; Isotope ; Diffusion ; Hydrogen ; Thermodynamics ; Chemistry ; Materials science ; Nuclear physics ; Physics ; Organic chemistry Nuclear Materials and Properties ; Nuclear reactor physics and engineering ; Fusion materials and technologies