Materials Science and Engineering Commons^™

Ten Questions Concerning The Implications Of Carpet On Indoor Chemistry And Microbiology, Sarah R, Haines, Rachel I. Adams, Brandon E. Boor, Thomas A. Bruton, John Downey, Andrea R. Ferro, Elliot Gall, +Several Additional Authors

Mechanical and Materials Engineering Faculty Publications and Presentations

Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices ...

Shapes Of Fe Nanocrystals Encapsulated At The Graphite Surface, Ann Lii-Rosales, Yong Han, Scott E. Julien, Olivier Pierre-Louis, Dapeng Jing, Kai-Tak Wan, Michael C. Tringides, James W. Evans, Patricia A. Thiel

Chemistry Publications

We describe and analyze in detail the shapes of Fe islands encapsulated under the top graphene layers in graphite. Shapes are interrogated using scanning tunneling microscopy. The main outputs of the shape analysis are the slope of the graphene membrane around the perimeter of the island, and the aspect ratio of the central metal cluster. Modeling primarily uses a continuum elasticity (CE) model. As input to the CE model, we use density functional theory to calculate the surface energy of Fe, and the adhesion energies between Fe and graphene or graphite. We use the shaft-loaded blister test (SLBT) model to ...

Ii-Vi Type-Ii Quantum Dot Superlattices For Novel Applications, Vasilios Deligiannakis

All Dissertations, Theses, and Capstone Projects

In this thesis, we discuss the growth procedure and the characterization results obtained for epitaxially grown submonolayer type-II quantum dot superlattices made of II-VI semiconductors. We have investigated the spin dynamics of ZnSe layers with embedded type-II ZnTe quantum dots and the use of (Zn)CdTe/ZnCdSe QDs for intermediate band solar cell (IBSC). Samples with a higher quantum dot density exhibit longer electron spin lifetimes, up to ~1 ns at low temperatures. Tellurium isoelectronic centers, which form in the ZnSe spacer regions as a result of the growth conditions, were also probed. A new growth sequence for type-II (Zn ...

Noble-Transition Alloy Absorbers For Near-Infrared Hot-Carrier Optoelectronics, Sara Karoline Figueiredo Stofela

LSU Doctoral Dissertations

Optoelectronics is the field of technology concerned with the study and application of electronic devices that source, detect and control light. Here we focus on the optical communications field which relies on optical fiber systems to carry signals to their destinations operating in the near-infrared range. To improve the performance of current optical fiber systems, one of the paths is to develop better near-infrared photodetectors.

The current group of materials used for near-infrared photodetection relies in the III-V semiconductor family. Although their spectral photosensitivity correlates well with the near-infrared, response time performance and electronic circuit integration remain limited for this ...

Development Of A Technology For Producing A Gel Composition For The Treat-Ment Of An Allergy Complicated By Fungal Infection, Filatova Albina Vasilevna, Turaev Abbaskhan Sabirkhanovich, Djurabaev Djalol Turgunbaevich

CHEMISTRY AND CHEMICAL ENGINEERING

The results of the development of the technology of the combined external drug for the treatment of allergies compli-cated by fungal infection are given. The rheological properties of the gel composition were studied in comparison with the similar preparation Fenistil gel, it was shown that the dynamic viscosity of the drug is 4.1 Pa·s, the active components (diphenylhydramine, fluconazole, Timoptin) do not destroy the structure of the gel base. A technological and instrumental scheme for the production of the drug has been developed.

Properties Of Model Rubber Compounds With Modified Angren Kaolin, Vapaev Murodjon Dusummatovih, Teshabaeva Elmira Ubaydullaevna, Ibadullaev Ahmadjon

CHEMISTRY AND CHEMICAL ENGINEERING

As a result of studies, the effect of modified Angren kaolin on the properties of elastomeric compositions based on synthetic polyisoprene and oil-filled styrene-butadiene rubbers were revealed. Plastoelastic and relaxation properties, as well as resistance to scorching and vulcanization kinetics of rubber compounds with traditional and modified Angren kaolin, were determined. The relationship of the elastic-strength properties of vulcanizates with the type and quantitative content of the modified Angren kaolin used is established.

Cleaning Gas Emissions From Carbon Dioxide, Bakhronov Khashim Shayimovich, Аkhmаtоv Аbdumalik Аbduvakhobovich, Ganieva Sabokhat Uktamovna, Suyarova Hilola Hakimovna

CHEMISTRY AND CHEMICAL ENGINEERING

The description of a pilot plant and results of a research of intensity of a heat mass transfer are provided and hy-draulic resistance at various initial concentration of the absorbed gas and relations of an expense of the liquid absorber to a consumption of gas mixture. It is established that use of water as the absorber of carbon dioxide doesn't provide necessary effectiveness of process. At absorption of carbon dioxide from an air with an aqueous solution of monoethanol amine in the hollow vortex device, with increase in concentration of CO2 (carbon dioxide) in steam-and-gas mixture on an entrance ...

Obtaining Of Magnesium Hydroxide From Dolomite From The Dehkanabad Deposit, Mixliyev Oybek, Bobokulova Oygul, Tadjiev Ilkham, Mirzakulov Kholtura Chorievich

CHEMISTRY AND CHEMICAL ENGINEERING

It was shown that the effect of pH on magniy hydroxide sediment degree in chemical pure solution content of dolo-mite which is affected by nitrogen acid. It was determined that sedimented based amound of magniy when the purified solu-tion of dolomite was neutral ized with gas ammonia at 11-12 pH. The filtration speed of magniy hydroxide is recorded 181 kg/m2h based on dry sediment. All solutions have reothologic properties.

Study Of Pt (Ii) Ion Sorption On Polymeric Sorbents Impregnated By Organic Ligands, Pardaev Otabek. Tuhtamishоvich, Daminova Shakhlo Sharipovna, Sharipov Khasan Turabovich

CHEMISTRY AND CHEMICAL ENGINEERING

The sorption and complex-forming properties of PAD600-based impregnated sorbents with respect to the Pt (II) ion were studied. The parameters of sorption extraction of platinum ions are determined. It was found that impregnated sorbents have the best sorption properties with respect to platinum cations. Based on the processing of the integral kinetic sorption curves, it has been established that the sorption process proceeds according to second-order models. The use of chemical kinetics models has shown that the stage of chemical interaction of platinum (II) ions with functional groups of the sorbent also contributes to the overall process rate.

Interfacial Contact Surface And The Size Of The Bubble In A Bubbling Extractor When Mixing Liquid Phases With An Inert Gas, Karimov Ikromali Tojimatovich

CHEMISTRY AND CHEMICAL ENGINEERING

The mixing of the liquid phases is carried out in the inner and outer zones of the apparatus. The main indicator of the mixing process is estimated by increasing the efficiency of the mass transfer process. This, depends on the size of the holes through which the inert gas passes into the mixing zones and the size of the bubbles emerging from the holes. Mixing the liquid phases is carried out depending on the size of the bubble arising in the interfacial contact surfaces of the bubbles. The article describes a method for determining the interfacial contact surfaces of a ...

Technical Decisions To Improvement The Technology Of Manufacture Of Flotation Potassium Chloride, Mirzakulov Kholtura, Kalanov Gayrat, Dormeshkin Oleg, Usmanov Ilkham

CHEMISTRY AND CHEMICAL ENGINEERING

Results of researches and calculations summarized for improving the technology of flotation potassium chloride from sylvinites of the Tyubegatan deposit. The possibility of decrease production costs associated with the preparation of saturated solutions for the leaching of sodium chloride, increasing the efficiency of the process of decontamination, filtering the concentrate of potassium chloride and halite waste are shown. Use of cyclonic dust to obtain a saturated solution of potassium chloride allows to decrease the costs of production potassium chloride from 11136 kg to 555 kg per a day and improve the marketability of the products. Installation after two hydrocyclones for ...

Crystal Structure Of The Cadmium Complexes With 2-Amino-1-Methylbenzimidazole, Rahmonova Dilnosa, Kadirova Zuhra, Hojamamberdiev Mirabboss, Daminova Shakhlo

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this work is the synthesis, study of the crystal and molecular structure of coordination compounds of cadmium with 2-amino-1-methylbenzimidazole. For the first time, the crystal structures of mixed ligand complexes of 2-amino-1-methylbenzimidazole (L) with various acidoligands (acetate and nitrate) with the distorted-octahedral structure of the metal polyhedron - [CdL2 (Ac)2] H2O and [CdL2 (NO3)2 (Н2О)2] were determined. The ligand molecule is coordinated through the nitrogen atom of the heterocyclic ring, the acidoligand is monodentate coordinated in the crystal structure of the complex. The presence of hydrated or innersphere water molecules in the molecules leads to ...

Phase Changes In Crystallization Of Some Glasses Synthesized In The Ro-Caf2-P2o5-Al2o3-Sio2 System, Aripova Mastura Khikmatovna, Rau Julietta V., Mkrtchyan Ripsime Vachaganovna

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the relearn was to study the phase changes during crystallization of some compositions of biocompatible glasses obtained in the RO-CaF2-P2O5-Al2O3-SiO2 (R=Zn, Mg) system. For this purpose, crystallization of glasses in the range of 700-1000 °C was carried out and X-ray analysis was carried out. A change in the phase composition of crystallized glass with a change in crystallization temperature and composition has been established. During crystallization, the phases of whitlockite, zinc-substituted fluorapatite, fluorapatite, anorthite, and gahnite were identified.

Magnetic And Transport Behaviors Of Non-Centrosymmetric Nd7ni2pd, Arjun K. Pathak, Yaroslav Mudryk, A. Provino, P. Manfrinetti, Vitalij K. Pecharsky

Ames Laboratory Accepted Manuscripts

Crystallographic, magnetic, electrical transport and thermodynamic properties of pseudo-binary Nd7Ni2Pd compound have been studied using temperature-dependent x-ray powder diffraction and physical property measurements. Compared to the ferromagnetic parent Nd7Pd3, the ground state of Nd7Ni2Pd is antiferromagnetic, and it exhibits strong metamagnetism. The measurements indicate two antiferromagnetic transitions in fields less than 8 kOe: a second-order paramagnetic to antiferromagnetic at TN2 = 29 K and a weak first-order antiferromagnetic to antiferromagnetic transition at TN1 = 24.5 K. The compound becomes ferromagnetic in fields of 8 kOe and higher with TC = 30 K. Temperature dependence of lattice parameters is anomalous, most prominently in ...

Exchange Bias In La0.7sr0.3cro3/La0.7sr0.3mno3/La0.7sr0.3cro3 Heterostructures, Rubyann Olmos, Hector Iturriaga, Dawn S. Blazer, Sanaz Koohfar, Kinjal Gandha, Ikenna C. Nlebedim, Divine P. Kumah, Srinivasa R. Singamaneni

Ames Laboratory Accepted Manuscripts

In the recent past, heterostructures of magnetic oxide thin films have attracted a great deal of research excitement due to very interesting physical properties such as antiferromagnetic interlayer coupling, tunable exchange-bias, interfacial driven magnetic properties and high mobility electron gas across the interfaces. In this work, we report on the comprehensive magnetic properties observed from the heterostructures of (2 unit cells) La0.7Sr0.3CrO3/(8 unit cells) La0.7Sr0.3MnO3/(2 unit cells) La0.7Sr0.3CrO3, which are epitaxially deposited on SrTiO3 substrate by plasma-assisted oxide molecular beam epitaxy. Using SQUID magnetometer, the magnetic properties are studied when the magnetic ...

Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt

Williams Honors College, Honors Research Projects

The dynamics of polymer thin films have been demonstrated to be significantly altered from the bulk, but the origins of such differences are not well defined. In this work, we seek to understand the differences in the structural dynamics (or physical aging) of polystyrene (PS) through branching and other well defined architectures (comb and centipede). The aging dynamics of ultrathin films (< 30 nm) differ from relatively thick films (100-150nm) with linear PS thin films aging more rapidly than the relatively “bulk-like” thick films. Ellipsometric measurements are used to characterize the physical aging rate of the films. The change in film thickness and refractive index as the films are held below the glass transition temperature (T_g) provides a simple measure of the physical aging. In this study, four different architectures (linear, comb, 4 arm star, and centipede) will be investigated. For each PS architecture, the aging rate will be determined for film thickness ranging ...

Perspective On Coarse-Graining, Cognitive Load, And Materials Simulation, Eric Jankowski, Nealee Ellyson, Jenny W. Fothergill, Michael M. Henry, Mitchell H. Leibowitz, Evan D. Miller, Mone't Alberts, Jamie D. Guevara, Chris D. Jones, Mia Klopfenstein, Kendra K. Noneman, Rachel Singleton, Matthew L. Jones

Materials Science and Engineering Faculty Publications and Presentations

The predictive capabilities of computational materials science today derive from overlapping advances in simulation tools, modeling techniques, and best practices. We outline this ecosystem of molecular simulations by explaining how important contributions in each of these areas have fed into each other. The combined output of these tools, techniques, and practices is the ability for researchers to advance understanding by efficiently combining simple models with powerful software. As specific examples, we show how the prediction of organic photovoltaic morphologies have improved by orders of magnitude over the last decade, and how the processing of reacting epoxy thermosets can now be ...

Hot Deformation Data For Haynes 214, Haynes 230 And Inconel 740h, Benjamin Adam, Julie Tucker, Graham Tewksbury

Mechanical and Materials Engineering Faculty Publications and Presentations

This article presents the datasets gathered for the hot processing of three Ni-based superalloys intended for A-USC application, Haynes 214, Haynes 230 and Inconel 740H. Isothermal compression tests were conducted with a Gleeble 3500 at temperatures between 1000 C and 1200 C and strain rates between 0.01/s and 1/s to a full true strain of 0.7. The obtained true stress-true strain curves were used as basis for hot processing maps, linking temperature, stress and strain rate. Subsequently, all samples were sectioned through the geometric centre to provide microstructural information, captured using EBSD, as well as EDX ...

The Effect Of Thermal History On The Atomic Structure Andmechanical Properties Of Amorphous Alloys, Nikolai V. Priezjev

Mechanical and Materials Engineering Faculty Publications

The influence of thermal processing on the potential energy, atomic structure, and mechanical properties of metallic glasses is examined using molecular dynamics simulations. We study the three-dimensional binary mixture, which was first relaxed near the glass transition temperature and zero pressure, and then rapidly cooled deep into the glass phase. It was found that glasses annealed at higher temperatures are relocated to higher energy states and their average glass structure remains more disordered, as reflected in the height of the first two peaks in the pair distribution function. The results of mechanical testing demonstrate that both the shear modulus and ...

Microstructure And Mechanical Behavior Of Metastable Beta Type Titanium Alloys, Chirag Dhirajlal Rabadia

Theses: Doctorates and Masters

Current biomaterials such as stainless steel, Co-Cr alloys, commercially pure titanium and Ti-6Al- 4V either possess poor mechanical compatibility and/or produce toxic effects in the human body after several years of usage. Consequently, there is an enormous demand for long-lasting biomaterials which provide a better combination of mechanical, corrosion and biological properties. In addition to this, alloys used in high-strength applications possess either high-strength or large plasticity. However, a high-strength alloy should possess a better blend of both strength and plasticity when used in high-strength applications. Metastable β-titanium alloys are the best suited alloys for biomedical and high-strength applications ...