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Design, Development, And Testing Of A Low Cost, Additively-Manufactured, Centrifugal Compressor, Aaron P. Bauer 2020 Air Force Institute of Technology

Design, Development, And Testing Of A Low Cost, Additively-Manufactured, Centrifugal Compressor, Aaron P. Bauer

Theses and Dissertations

The three objectives of this research were to: 1.) design, build, and test AM compressors to substitute into COTS micro-gas turbine engines, 2.) provide initial correlations between FEA and compressor failure speed, and 3.) characterize the effects of AM on compressor performance. These goals improved the design cycle cost and the design-validation time cycle. ULTEM 9085, 300-AMB, and Onyx-Kevlar temperature-dependent tensile properties were measured. FEA-predicted failure speeds of stock compressor designs led design improvements, potentially fulfilling the original compressor requirements. Physical testing of the stock and ULTEM 9085 compressors occurred. Comparing these compressors' performances demonstrated that low cost, AM materials ...


Modeling Hybrid Composites Using Tsai-Wu And Hashin Failure Criterion, Candice R. Roberts 2020 Air Force Institute of Technology

Modeling Hybrid Composites Using Tsai-Wu And Hashin Failure Criterion, Candice R. Roberts

Theses and Dissertations

Hybrid composites require further study and testing for future use in various fields. This study focuses on simulating a Hybrid Composite using IM7-977-3 laminae with steel foils in Abaqus under bolt loading by using Hashin and Tsai-Wu failure criterion. Initial simulations contain only the IM7-977-3 composite with cohesive layers. Foil samples were then tested for accurate material properties from which the simulations were then updated to include steel foils. The two models show that Tsai-Wu failure criterion, while great for anisotropic material in tension, does not prove accuracy around the hole of the composite material which is in compression. Hashin ...


Fatigue Behavior Of An Advanced Melt-Infiltrated Sic/Sic Composite With Environmental Barrier Coating At 1200°C In Air And In Steam, Thaddeus M. Williams 2020 Air Force Institute of Technology

Fatigue Behavior Of An Advanced Melt-Infiltrated Sic/Sic Composite With Environmental Barrier Coating At 1200°C In Air And In Steam, Thaddeus M. Williams

Theses and Dissertations

Advanced aerospace applications such as aircraft turbine engine components, hypersonic flight vehicles, and spacecraft reentry thermal protection systems require structural materials that have superior long-term mechanical properties under high temperature, high pressure, and varying environmental factors, such as moisture. Because of their low density, high strength and fracture toughness at high temperatures SiC fiber-reinforced SiC matrix composites are being evaluated for aircraft engine hot-section components. In these applications the composites will be subjected to various types of mechanical loadings at elevated temperatures in oxidizing environments. Because their constituents are intrinsically oxidation-prone, the most significant problem hindering SiC/SiC composites is ...


Solution Anneal Heat Treatments To Enhance Mechanical Performance Of Additively Manufactured Inconel 718, David J. Newell 2020 Air Force Institute of Technology

Solution Anneal Heat Treatments To Enhance Mechanical Performance Of Additively Manufactured Inconel 718, David J. Newell

Theses and Dissertations

The nickel-based superalloy Inconel 718 (IN718) is an excellent candidate among aerospace alloys for laser powder-bed fusion (LPBF) manufacturing. As-built LPBF IN718 has a vertically aligned columnar (001) microstructure which translates into orthotropic mechanical behavior. The post-process heat treatments for IN718 were developed 60 years ago for wrought and cast processes and do not mitigate the columnar microstructure of the LPBF process. Recrystallization is required to remove the columnar microstructure, which would allow for parts to be fabricated on different machines or in different orientations but still achieve the same properties. This research investigated the microstructure of LPBF IN718 as ...


Anomalous Eutectic Microstructures In Mg-Al Structural Alloy Prepared By Rapid Solidification, Soodabeh Azadehranjbar, Jian Wang, Jeffrey E. Shield 2020 University of Nebraska-Lincoln

Anomalous Eutectic Microstructures In Mg-Al Structural Alloy Prepared By Rapid Solidification, Soodabeh Azadehranjbar, Jian Wang, Jeffrey E. Shield

Mechanical (and Materials) Engineering -- Dissertations, Theses, and Student Research

Magnesium is the lightest engineering metal 1 However, conventional Mg alloys typically suffer from low strength and poor deformability due to very few slip systems and easy twinning 3 Alloying Mg with other materials and microstructural engineering are promising approaches to increase ductility and strength of Mg In the current work, non equilibrium solidification conditions were applied to induce a transition from regular to anomalous eutectic in Mg Al eutectic alloy such that four distinguished microstructures were acquired and the corresponding formation mechanisms were investigated


Fabrication Of 2d And 3d High-Resolution Binder-Free Graphene Circuits Using A Microfluidic Approach For Sensor Applications, Metin Uz, Matthew T. Lentner, Kyle Jackson, Maxsam S. Donta, Juhyung Jung, John Hondred, Eric Mach, Jonathan C. Claussen, Surya K. Mallapragada 2020 Iowa State University

Fabrication Of 2d And 3d High-Resolution Binder-Free Graphene Circuits Using A Microfluidic Approach For Sensor Applications, Metin Uz, Matthew T. Lentner, Kyle Jackson, Maxsam S. Donta, Juhyung Jung, John Hondred, Eric Mach, Jonathan C. Claussen, Surya K. Mallapragada

Chemical and Biological Engineering Publications

In this study, a simple microfluidic method, which can be universally applied to different rigid or flexible substrates, was developed to fabricate high-resolution, conductive, 2D and 3D microstructured graphene-based electronic circuits. The method involves controlled and selective filling of microchannels on substrate surfaces with a conductive binder-free graphene nanoplatelets (GNP) solution. The ethanol-thermal reaction of GNP solution at low temperatures (~75 °C) prior to microchannel filling (pre-heating) further reduces GNP, enhances conductivity, reduces sheet resistance (~0.05 kΩ sq-1), enables room temperature fabrication and eliminates harsh post-processing, which makes this fabrication technique compatible with degradable substrates. This method can also ...


Light Control Of Surface–Bulk Coupling By Terahertz Vibrational Coherence In A Topological Insulator, Xu Yang, Liang Luo, Chirag Vaswani, Xin Zhao, Yongxin Yao, Di Cheng, Zhiyan Liu, Richard H. J. Kim, Xinyu Liu, Malgorzata Dobrowolska-Furdyna, Jacek K. Furdyna, Ilias E. Perakis, Cai-Zhuang Wang, Kai-Ming Ho, Jigang Wang 2020 Iowa State University and Ames Laboratory

Light Control Of Surface–Bulk Coupling By Terahertz Vibrational Coherence In A Topological Insulator, Xu Yang, Liang Luo, Chirag Vaswani, Xin Zhao, Yongxin Yao, Di Cheng, Zhiyan Liu, Richard H. J. Kim, Xinyu Liu, Malgorzata Dobrowolska-Furdyna, Jacek K. Furdyna, Ilias E. Perakis, Cai-Zhuang Wang, Kai-Ming Ho, Jigang Wang

Ames Laboratory Accepted Manuscripts

The demand for disorder-tolerant quantum logic and spin electronics can be met by generating and controlling dissipationless spin currents protected by topology. Dirac fermions with helical spin-locking surface transport offer a way of achieving such a goal. Yet, surface-bulk coupling can lead to strong Dirac electron scattering with bulk carriers and phonons as well as impurities, assisted by such dissipative channel, which results in “topological breakdown”. Here, we demonstrate that coherent lattice vibrations periodically driven by a single-cycle terahertz (THz) pulse can significantly suppress such dissipative channel in topological insulators. This is achieved by reducing the phase space in the ...


Subsurface Cooling Rates And Microstructural Response During Laser Based Metal Additive Manufacturing, Vivek Thampy, Anthony Y. Fong, Nicholas P. Calta, Jenny Wang, Aiden A. Martin, Philip J. Depond, Andrew M. Kiss, Gabe Guss, Qingfeng Xing, Ryan T. Ott, Anthony van Buuren, Michael F. Toney, Johanna Nelson Weker, Matthew J. Kramer, Manyalibo J. Matthews, Christopher J. Tassone, Kevin H. Stone 2020 SLAC National Accelerator Laboratory

Subsurface Cooling Rates And Microstructural Response During Laser Based Metal Additive Manufacturing, Vivek Thampy, Anthony Y. Fong, Nicholas P. Calta, Jenny Wang, Aiden A. Martin, Philip J. Depond, Andrew M. Kiss, Gabe Guss, Qingfeng Xing, Ryan T. Ott, Anthony Van Buuren, Michael F. Toney, Johanna Nelson Weker, Matthew J. Kramer, Manyalibo J. Matthews, Christopher J. Tassone, Kevin H. Stone

Ames Laboratory Accepted Manuscripts

Laser powder bed fusion (LPBF) is a method of additive manufacturing characterized by the rapid scanning of a high powered laser over a thin bed of metallic powder to create a single layer, which may then be built upon to form larger structures. Much of the melting, resolidification, and subsequent cooling take place at much higher rates and with much higher thermal gradients than in traditional metallurgical processes, with much of this occurring below the surface. We have used in situ high speed X-ray diffraction to extract subsurface cooling rates following resolidification from the melt and above the β-transus ...


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 2020 Iowa State University and Ames Laboratory

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 ...


Defect-Free Plastic Deformation Through Dimensionality Reduction And Self-Annihilation Of Topological Defects In Crystalline Solids, Yipeng Gao, Yongfeng Zhang, Larry K. Aagesen, Jianguo Yu, Min Long, Yunzhi Wang 2020 Idaho National Laboratory

Defect-Free Plastic Deformation Through Dimensionality Reduction And Self-Annihilation Of Topological Defects In Crystalline Solids, Yipeng Gao, Yongfeng Zhang, Larry K. Aagesen, Jianguo Yu, Min Long, Yunzhi Wang

Computer Science Faculty Publications and Presentations

As a signature of symmetry-breaking processes, the generation and annihilation of topological defects (domain walls, strings, etc.) are of great interest in condensed matter physics and cosmology. Here we propose a distinctive self-organization process through phase transitions, in which all the generated topological defects are dimensionality reduced and self-annihilated. In crystalline solids, such a unique mechanism allows a perfect single crystal after plastic deformation, which originates from the coupling of different types of broken symmetries.


Ii-Vi Type-Ii Quantum Dot Superlattices For Novel Applications, Vasilios Deligiannakis 2020 City University of New York (CUNY)

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 ...


Differential Effect Of Magnetic Alignment On Additive Manufacturing Of Magnetocaloric Particles, Karam N. Al-Milaji, Shalabh Gupta, Vitalij K. Pecharsky, Radhika Barua, Hong Zhao, Ravi L. Hadimani 2020 Virginia Commonwealth University

Differential Effect Of Magnetic Alignment On Additive Manufacturing Of Magnetocaloric Particles, Karam N. Al-Milaji, Shalabh Gupta, Vitalij K. Pecharsky, Radhika Barua, Hong Zhao, Ravi L. Hadimani

Ames Laboratory Accepted Manuscripts

Additive manufacturing of materials using magnetic particles as feedstock has attracted tremendous attention during the past decade owing to its ability to tune both shape and magnetocrystalline anisotropy, which can significantly enhance the magnetic characteristics of materials. We demonstrate that the magnetic response of multilayered thin films of Gd5Si4 can be tailored by controlling the external magnetic field during inkjet printing. The external magnetic field aligns the magnetic particles along their magnetic easy axis, enhancing the magnetic anisotropy of the printed films. Our work demonstrates the ability to print thin magnetic films with a defined anisotropy in any chosen direction ...


Noble-Transition Alloy Absorbers For Near-Infrared Hot-Carrier Optoelectronics, Sara Karoline Figueiredo Stofela 2020 Louisiana State University

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 2020 Institute of Bioorganic Chemistry, Tashkent, Uzbekistan

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 2020 Tashkent Chemiсal-Technological Institute, Uzbekistan

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 2020 Navoi State Mining Institute, Uzbekistan

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 2020 Tashkent Chemical-Technological Iinstitute, Uzbekistan

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 2020 Termez State University, Uzbekistan

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 2020 Fergana Polytechnic Institute, Fergana, Uzbekistan

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 2020 Tashkent Chemical - Technological Institute, Tashkent, Uzbekistan

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 ...


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