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Articles 5521 - 5550 of 16712

Full-Text Articles in Engineering

A Modified Johnson-Cook Model Incorporating The Effect Of Grain Size On Flow Stress, S. Ganguly, Mario F. Buchely, K. Chandrashekhara, Semen Naumovich Lekakh, Ronald J. O'Malley Sep 2020

A Modified Johnson-Cook Model Incorporating The Effect Of Grain Size On Flow Stress, S. Ganguly, Mario F. Buchely, K. Chandrashekhara, Semen Naumovich Lekakh, Ronald J. O'Malley

Materials Science and Engineering Faculty Research & Creative Works

The mechanical properties of steel are influenced by grain size, which can change through mechanisms such as nucleation and growth at elevated temperatures. However, the classic Johnson-Cook model that is widely used in hot deformation simulations does not consider the effect of grain size on flow stress. In this study, the Johnson-Cook model was modified to incorporate the effects of austenite grain size on flow stress. A finite element model was employed to characterize the effects of grain size on the flow stress for different steel grades over a range of temperatures (900⁰ to 1300⁰). Simulation results show good agreement …

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New Experimental Apparatus To Investigate Hot Tearing Behavior In Steel, Yanru Lu, Laura Bartlett, Ronald J. O'Malley, Semen Naumovich Lekakh, Mario F. Buchely Sep 2020

New Experimental Apparatus To Investigate Hot Tearing Behavior In Steel, Yanru Lu, Laura Bartlett, Ronald J. O'Malley, Semen Naumovich Lekakh, Mario F. Buchely

Materials Science and Engineering Faculty Research & Creative Works

Hot tearing is a complex thermomechanical phenomenon occurring in the semi-solid region. Strain in this region can induce cracking and localized alloying element segregation. An apparatus for investigating hot tearing was developed utilizing a servo-motor controlled cylinder to apply a pre-determined amount of strain to the solidifying shell. A special mold was developed using filling and solidification modeling to ensure that dendrite growth was perpendicular to applied strain. A computer-automated system was utilized to control the strain and strain rate and measure the force and displacement. Solidification experiments utilizing AISI 1020 steel validated the apparatus capabilities and optimized testing parameters.

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Peritectic Behavior Detection In The Fe-C-Mn-Al-Si Steel System Using Fiber Optic Temperature Mapping, Muhammad Roman, Damilola Balogun, Rex E. Gerald Ii, Laura Bartlett, Jie Huang, Ronald J. O'Malley Sep 2020

Peritectic Behavior Detection In The Fe-C-Mn-Al-Si Steel System Using Fiber Optic Temperature Mapping, Muhammad Roman, Damilola Balogun, Rex E. Gerald Ii, Laura Bartlett, Jie Huang, Ronald J. O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Peritectic reactions can cause surface defects and breakouts in continuous casting and the peritectic region is often avoided by adjusting the chemical composition of the steel to cast outside of the peritectic sensitivity range. However, the combined effects of C, Mn, Al, and Si on the boundaries that map peritectic region are still disputed for many advanced high strength steel grades. An apparatus for performing controlled solidification experiments is being developed to characterize the effects of chemical composition on the uniformity of shell growth during solidification using a copper chill mold with an embedded fiber-optic temperature sensor that enables high …

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Effects Of Solid Lubricants On Properties Of Al-Si-Sic Composite Powderproduced By Gas Atomization Technique, Haris Rudianto, Sang Sun Yang, Yong Jin Kim, Ivo Dlouhy, Wahyu Caesarendra Sep 2020

Effects Of Solid Lubricants On Properties Of Al-Si-Sic Composite Powderproduced By Gas Atomization Technique, Haris Rudianto, Sang Sun Yang, Yong Jin Kim, Ivo Dlouhy, Wahyu Caesarendra

Journal of Metals, Materials and Minerals

Al-Si-SiC composites powder was analyzed in this research. The powder was made by gas atomizing process. Powder characterization was done to observe its morphology, particle size distribution and thermal properties. Effects of lubricants were intensively investigated in this research with compositions and pressure variables. It is assumed that higher amount of solid lubricant put into the powder, the lower ejection force needed to take out compacted powder. Finding appropriate solid lubricant is necessary to improve green and sintering properties. EBS (ethylene bis stearamide), aluminum stearate, zinc stearate and paraffin wax were used for investigation. Sintering under ultra high purity nitrogen …

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Observation Of Structural, Spectral Characterizations And Correlation Of Physical Parameters On Vo2+ Ions Doped Cadmium Lithium Sodium Borate Glasses, Mekala Avinash, Shaik Johny Basha, Vinukonda Khidhirbrahmendra, Annur Vivekananda Chandrasekhar, Renduchintala Venkata Satya Sri, Nagoji Ravikumar Sep 2020

Observation Of Structural, Spectral Characterizations And Correlation Of Physical Parameters On Vo2+ Ions Doped Cadmium Lithium Sodium Borate Glasses, Mekala Avinash, Shaik Johny Basha, Vinukonda Khidhirbrahmendra, Annur Vivekananda Chandrasekhar, Renduchintala Venkata Satya Sri, Nagoji Ravikumar

Journal of Metals, Materials and Minerals

A series of quinary 0.1 mol% VO2+ doped Cadmium Lithium Sodium Borate(CLNB) glass system with varying alkali (Li2O/Na2O) content were prepared by the classical melt quenching technique. The current research was carried out to observe the physical, structural and spectral parameters alter with the variation of alkali content in nonlinear manner. Physical properties such as the oxide ion polarizability (∝ைయష), optical basicity of prepared glass (Λth), Yamashita and Kuroswa's interaction parameter (Α) and the third order nonlinear optical polarizability ((3)) are calculated by compared with altering the alkali mol% and also correlate them with each other. Physical parameters are varying …

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Tailoring And Remotely Switching Performance Of Ultrafiltration Membranes By Magnetically Responsive Polymer Chains, Anh Vu, Arijit Sengupta, Emily Freeman, Xianghong Qian, Mathias Ulbricht, S. Ranil Wickramasinghe Sep 2020

Tailoring And Remotely Switching Performance Of Ultrafiltration Membranes By Magnetically Responsive Polymer Chains, Anh Vu, Arijit Sengupta, Emily Freeman, Xianghong Qian, Mathias Ulbricht, S. Ranil Wickramasinghe

Chemical Engineering Faculty Publications and Presentations

Magnetically responsive ultrafiltration membranes were prepared by grafting poly(2-hydroxyethyl methacrylate) chains from the outer surface of 100-kDa regenerated cellulose ultrafiltration membranes. Surface-initiated atom transfer radical polymerization was used to graft the polymer chains. Grafting from the internal pore surface was suppressed by using glycerol as a pore-filling solvent during initiator immobilization at varied densities. Glycerol suppresses the initiator attachment to the pore surface. Polymerization times of up to four hours were investigated. Superparamagnetic nanoparticles were covalently attached to the chain end. Membrane performance was determined using bovine serum albumin and dextran as model solutes. Increasing the grafted polymer chain density …

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Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee Sep 2020

Development Of Zeolitic Imidazolate Frameworks For Enhancing Post-Combustion Co2 Capture, Dustin Lee

Master's Theses

Post-combustion CO2 capture is a promising approach for complementing other strategies to mitigate climate change. Liquid absorption is currently used to capture CO2 from post-combustion flue gases. However, the high energy cost required to regenerate the liquid absorbents is a major drawback for this process. As a result, solid sorbents have been investigated extensively in recent years as alternative media to capture CO2 from flue gases. For example, metal organic frameworks (MOFs) are nanoporous materials that have high surface areas, large pore volumes, and flexible designs. A large number of MOFs, however, suffer from 1) low CO …

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Review On The Suppression Of Zn Dendrite For High Performance Of Zn Ion Battery, Jufni Abdulla, Jin Cao, Panyawat Wangyao, Jiaqian Qin Sep 2020

Review On The Suppression Of Zn Dendrite For High Performance Of Zn Ion Battery, Jufni Abdulla, Jin Cao, Panyawat Wangyao, Jiaqian Qin

Journal of Metals, Materials and Minerals

Researchers are paying more attention to the environmentally friendly and low-cost energy storage devices, due to the environmental issues and energy crisis caused by current commercial energy storage technologies. Zinc ion battery (ZIB) is one of the new, environment-friendly and low-cost energy storage technologies, which is the most promising alternative technology to replace the lithium ion battery applications. However, one of the challenges-dendrite growths during cycling of Zn anode is still limited its practical applications. In this review, the recent progress on suppression of Zn dendrite in various electrode design, electrolyte additives, and separator modifications for ZIBs is summarized.

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Influence Of Cnts Addition On Structural And Superconducting Properties Of Mechanically Alloyed Mgb2, Sigitdwi Yudanto, Yulia Puspa Dewi, Perdamean Sebayang, Septian Adichandra, Agung Imaduddin, Budhy Kurniawan, Azwar Manaf Sep 2020

Influence Of Cnts Addition On Structural And Superconducting Properties Of Mechanically Alloyed Mgb2, Sigitdwi Yudanto, Yulia Puspa Dewi, Perdamean Sebayang, Septian Adichandra, Agung Imaduddin, Budhy Kurniawan, Azwar Manaf

Journal of Metals, Materials and Minerals

The result of adding carbon nanotubes (CNTs) to the lattice parameters, critical temperature and electrical resistivity of the MgB2 superconductors is reported.Structurally, the addition of CNTs was found to decrease the a-lattice from 3.086 Å of CNTs free sample to 3.078 Å and 3.074 Å of 5% and 10% CNTs added samples due to a substitution of C at the B site which presence in the form of Mg(B1-xCx)2 main phase. The doping level x of CNTs added samples were 2.25 at% and 3.75 at% respectively. The unreacted CNTs presence as the second phase and further acting as the suppression …

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Effects Of Quenchants On Microstructures And Mechanical Properties Ofsteel Gradeaisi 5160, Pattama Apichai Sep 2020

Effects Of Quenchants On Microstructures And Mechanical Properties Ofsteel Gradeaisi 5160, Pattama Apichai

Journal of Metals, Materials and Minerals

This research aims to study the effects of the quenchants in hardening process on microstructures and mechanical properties of alloy steel grade AISI 5160. The heat treatments include hardening at 900 (Q1), 870 (Q2), 840 (Q3), 810 (Q4) and 780°C (Q5),respectively, followed by quenching into water, oil and brine solution. Microstructures were measured scanning electron microscopy and energy dispersive X-ray spectroscopy.For each condition, hardness and tensile testing were measured. It was found that the microstructure in the as-sheetcondition consisted of ferrite and pearlite. The observed microstructures after quenching process were martensitewith a small amount of retained austainite. The hardening at …

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Optical Properties Of Tio2@Ag Nanowires And Nanospheres, Thananchai Dasri, Panuwat Chaiyachate, Sasiporn Audtarat, Panadda Charee, Artit Chingsungnoen Sep 2020

Optical Properties Of Tio2@Ag Nanowires And Nanospheres, Thananchai Dasri, Panuwat Chaiyachate, Sasiporn Audtarat, Panadda Charee, Artit Chingsungnoen

Journal of Metals, Materials and Minerals

Nanoparticles (NPs) with nonmetallic cores and metallic shells (such as Au, Ag, and Cu) can exhibit improve absorption efficiency due to localized surface plasmon resonance (LSPR), charge density oscillations at the surfaces of these core-shell composite nanoparticles. In this study, the effect of the geometry of TiO2@Ag core-shell composite nanoparticles on their optical absorption properties was theoretically illustrated in the wavelength ranges between the visible and infrared light regions of electromagnetic radiation. These nanostructures were modeled by varying the TiO2 core and Ag shell radii of the composite nanospheres and nanowires. The results indicate that varying the TiO2 core radius …

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Incorporation Of Fe And Cu For Antibacterial Performance Enhancement Of Fe-Cu-Zno Nanocomposites Synthesized By A Facile Chemical Precipitation, Sucheewan Krobthong, Sutthipoj Wongrerkdee Sep 2020

Incorporation Of Fe And Cu For Antibacterial Performance Enhancement Of Fe-Cu-Zno Nanocomposites Synthesized By A Facile Chemical Precipitation, Sucheewan Krobthong, Sutthipoj Wongrerkdee

Journal of Metals, Materials and Minerals

Fe-Cu-ZnO nanocomposites were synthesized using simple chemical precipitation under a violent stirring condition, and characterized by dynamic light scattering, ultraviolet-visible spectroscopy, scanning electron microscopy, X-ray diffractometry, Raman spectroscopy, and vibrating sample magnetometer. The particle size distribution is observed not only a large size of 100 nm to 2 m, but also a small size of 0.4-5.0 nm. The absorbance peaks of the nanocomposites exhibit a small blue shift in comparison with ZnO. Surface defects are explored in the nanocomposites including irregular shapes, rough surfaces, and aggregation. The nanocomposites and ZnO have similar hexagonal wurtzite structures. However, the nanocomposites have more …

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Corrosion And Cavitation Erosion Properties Of Sub-Micron Wc-Co /Cr3c2-Nicr Multi-Layered Coating On Aluminium Substrates, Srinivas Vadapalli, Umachaitanya Pathem, Venkata Ramana S N Vuppala, Kodandarama Rao Chebattina, Jaikumar Sagari Sep 2020

Corrosion And Cavitation Erosion Properties Of Sub-Micron Wc-Co /Cr3c2-Nicr Multi-Layered Coating On Aluminium Substrates, Srinivas Vadapalli, Umachaitanya Pathem, Venkata Ramana S N Vuppala, Kodandarama Rao Chebattina, Jaikumar Sagari

Journal of Metals, Materials and Minerals

Marine and automobile components are subjected to corrosion and cavitation erosion during their service. This paper aims to study the use of hard coatings on aluminium substrates with multiple layers of coating comprising of sub-micron sized WC-Co andCr3C2-NiCr for enhancement of hardness, corrosion and cavitation erosion properties. Coatings are applied on aluminium substrates using high-velocity liquid fuel (HVLF) spray technique and the coating parameters are optimized for best results. The results indicate that multiple layered coating with alternate film coatings of Cr3C2-NiCr & submicron WC-Co has significantly improved the hardness of aluminium surface. The resistance to corrosion with multiple layers …

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Impact Of Fillers For Acrylic Compositions On Their Stability In Aggressive Mediums And Adhesive Strength, Liudmyla Trykoz, Svetlana Kamchatnaya, Oksana Pustovoitova, Inna Saiapina, Dmytro Borodin Sep 2020

Impact Of Fillers For Acrylic Compositions On Their Stability In Aggressive Mediums And Adhesive Strength, Liudmyla Trykoz, Svetlana Kamchatnaya, Oksana Pustovoitova, Inna Saiapina, Dmytro Borodin

Journal of Metals, Materials and Minerals

This paper aims to reveal the change of diffusion coefficient and permeability of the acrylic composition with different types of fillers (such as cement, sand, mica, and talc) in the various aggressive mediums. Also, the adhesive strength was determined as the maximal stress caused by detaching metal plate from the surface of the concrete. To evaluate the stability of the compositions, the samples of the acrylic compositions were saturated with acid and alkali solutions during a certain time. Basing on the mass change, the coefficients of diffusion, sorption, and permeability were calculated. The sand filled acrylic composition showed the least …

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Experimental And Numerical Investigation Of The Influence Of Temperature On The Fracture Behavior Of High Impact Polystyrene Evaluated By The J-Integral Approach Using Multiple Specimen Method, Hanan El Bhilat, Abdelilah Hachim, Houda Salmi, Khalid El Had Sep 2020

Experimental And Numerical Investigation Of The Influence Of Temperature On The Fracture Behavior Of High Impact Polystyrene Evaluated By The J-Integral Approach Using Multiple Specimen Method, Hanan El Bhilat, Abdelilah Hachim, Houda Salmi, Khalid El Had

Journal of Metals, Materials and Minerals

The aim of the present work is to study the mechanical behavior in fracture of high impact polystyrene (HIPS) subjected to tensile tests under the effect of temperature to determine the R-curves. The theory of the J-integral contour has been used for the development of a characterization method of the fracture strength appropriate to the case of this non-linear elastoplastic polymer material. To this end, we used the method of multiple specimens (Single edge notch tension SENT) of thin thickness; we used several identical test pieces containing cracks of the same lengths. The tensile tests wereconducted under different temperatures, ranging …

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Optimization Of Wet Sliding Wear Parameters Of Titanium Grade 2 And Grade 5 Bioimplant Materials For Orthopedic Application Using Taguchi Method, Sachin Ganeshrao Solanke, Vivek R. Gaval Sep 2020

Optimization Of Wet Sliding Wear Parameters Of Titanium Grade 2 And Grade 5 Bioimplant Materials For Orthopedic Application Using Taguchi Method, Sachin Ganeshrao Solanke, Vivek R. Gaval

Journal of Metals, Materials and Minerals

In this research ball on disc wear tests have been carried out on Titanium grade 2 and Titanium grade 5 material using ASTM G-99 standard at room temperature in simulated body fluid. The tribological property such as the weight loss was studied by using the Taguchi design of experiments. The design of experiment was done using an L18 orthogonal array. An analysis of variance demonstrated that the individual contribution such as the applied normal load factor was 91.17% for weight loss, which means it is highest individual contribution as compared to other factors so it was concluded that weight loss …

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Processing And Properties Of Medium-Mn Trip Steel To Obtain A Two-Stage Trip Behavior, D. M. Field, L. G. Garza-Martinez, D. C. Van Aken Sep 2020

Processing And Properties Of Medium-Mn Trip Steel To Obtain A Two-Stage Trip Behavior, D. M. Field, L. G. Garza-Martinez, D. C. Van Aken

Materials Science and Engineering Faculty Research & Creative Works

Two medium-Mn steels of nominal composition 0.15C-2.0Si-10.5Mn-(0.75, 1.5) Al-0.04Nb-balFe (wt pct) were processed to produce sub-micron grain sizes of 0.65 and 0.80 μm. Mechanical testing was performed in three successive conditions: hot rolled, intercritically annealed, and cold rolled with subsequent intercritical annealing. Intercritical annealing was performed at 923 K for 20 hours. Electron-backscattered diffraction and X-ray diffraction were utilized to characterize the microstructure, consisting of α-ferrite, α-martensite, ε-martensite, and γ-austenite. Microstructural constituents were tracked during tensile deformation, and it was found that both steels exhibited two-stage TRIP with γ-austenite martensitically transforming first to ε-martensite and as strain increased ε-martensite transformed …

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A Data-Driven Approach For Predicting Nepheline Crystallization In High-Level Waste Glasses, Irmak Sargin, Charmayne E. Lonergan, John D. Vienna, John S. Mccloy, Scott P. Beckman Sep 2020

A Data-Driven Approach For Predicting Nepheline Crystallization In High-Level Waste Glasses, Irmak Sargin, Charmayne E. Lonergan, John D. Vienna, John S. Mccloy, Scott P. Beckman

Materials Science and Engineering Faculty Research & Creative Works

High-level waste (HLW) glasses with high alumina content are prone to nepheline crystallization during the slow canister cooling that is experienced during large-scale production. Because of its detrimental effects on glass durability, nepheline (NaAlSiO4) precipitation must be avoided; however, developing robust, predictive models for nepheline crystallization behavior in compositionally complex HLW glasses is difficult. Using overly conservative constraints to predict nepheline formation can limit the waste loading to lower than the achievable capacity. In this study, a robust data-driven model using five compositional features has been developed to predict nepheline formation. A new descriptor is introduced called the …

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Chitosan Beads As The Adsorbent For Glyphosate Removal From An Aqueous Solution, Thanat Saelim, Sermpong Sairiam, Krisana Siralertmukul, Supawin Watcharamul, Roongkan Nuisin Sep 2020

Chitosan Beads As The Adsorbent For Glyphosate Removal From An Aqueous Solution, Thanat Saelim, Sermpong Sairiam, Krisana Siralertmukul, Supawin Watcharamul, Roongkan Nuisin

Journal of Metals, Materials and Minerals

Chitosan beads were prepared to remove glyphosate from an aqueous solution via a batch adsorption system. The optimum conditions, including initial glyphosateconcentration, adsorbent dose, and contact time, were investigated. Increasing the initial glyphosate concentration increased the equilibrium adsorption capacity onto the chitosan beads. The rapid sorption of glyphosate was found at an initial contact time of 30 min. The maximum adsorption capacity from 35 mg·L-1 glyphosate in solution onto 0.1 g chitosan beads was 12.7 mg·g-1. Increasing amount chitosan to 0.5 g dosage could remove more than 94% of the glyphosate for all initial glyphosate concentrations (1 - 35 mg·L-1), …

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Microstructure Evolution And Mechanical Properties Of Calcined Kaolin Processing Waste-Based Geopolymers In The Presence Of Different Alkaliactivator Content By Pressing And Casting, Sitthisak Prasanphan, Anucha Wannagon, Takaomi Kobayashi, Sirithan Jiemsirilers Sep 2020

Microstructure Evolution And Mechanical Properties Of Calcined Kaolin Processing Waste-Based Geopolymers In The Presence Of Different Alkaliactivator Content By Pressing And Casting, Sitthisak Prasanphan, Anucha Wannagon, Takaomi Kobayashi, Sirithan Jiemsirilers

Journal of Metals, Materials and Minerals

In this work, microstructure evolution and mechanical properties of calcined kaolin processing waste-based geopolymers in the presence of low and high contents alkali activators were studied. Lower and higher contents of alkali activators were employed to synthesize geopolymers by pressing and casting methods, respectively. Chemicalbonding analysis, microstructure/elemental analysis, phase composition analysis, and compressive strength test were performed using FTIR, SEM/EDX, XRD, anduniversal mechanical testing machine, respectively. Findings showed that geopolymer with the low content of alkali activator formed by pressing (pressed geopolymer) might promote in the higher degree of geopolymerization because of higher compacted matrices but geopolymer with the high …

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Fatigue Of A Sic/Sic Ceramic Composite With An Ytterbium‐Disilicate Environmental Barrier Coating At Elevated Temperature, Marina B. Ruggles-Wrenn, Thaddeus M. Williams Sep 2020

Fatigue Of A Sic/Sic Ceramic Composite With An Ytterbium‐Disilicate Environmental Barrier Coating At Elevated Temperature, Marina B. Ruggles-Wrenn, Thaddeus M. Williams

Faculty Publications

Excerpt: Tension-tension fatigue performance of a SiC/SiC composite with an ytterbium-disilicate environmental barrier coating (EBC) was investigated at 1200°C in air and steam. The composite is reinforced with Hi-Nicalon™ SiC fibers and has a melt-infiltrated matrix processed by chemical vapor infiltration of SiC with subsequent infiltration with SiC particulate slurry and molten silicon. Abtract © American Ceramic Society

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Optimized Transconductance Designs To Enhance The Linearity Performance Of Rf Front-End Receiver Circuits In 130 Nm Cmos Technology, Nandini Vitee Sep 2020

Optimized Transconductance Designs To Enhance The Linearity Performance Of Rf Front-End Receiver Circuits In 130 Nm Cmos Technology, Nandini Vitee

Student Works (2020-2029)

Highly linear front-end circuits are greatly desired for wireless receivers to improve the dynamic range. However, intermodulation distortions caused by the non-linear transconductor current limits the linearity of the front-end receiver circuit in CMOS technologies. In addition to the inherent nonlinear effect, the downscaling of CMOS further exacerbates the linearity of the circuit due to lower voltage headroom and high-field mobility. Thus, it is essential to develop effective circuit techniques that can aid linearity enhancement without jeopardizing other preferred performances such as low noise, high conversion gain, and low-power consumption. In this thesis, two different high linear transconductors are presented …

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Retention Of Amorphous Silica In Rice Hulls At High Temperatures, Takeshi Okutani Sep 2020

Retention Of Amorphous Silica In Rice Hulls At High Temperatures, Takeshi Okutani

Journal of Metals, Materials and Minerals

Rice hulls contain around 20 wt% amorphous silica (rice hull silica). Rice hullsilica containing no potassium impurity crystallized from amorphous silica to cristobaliteat 1300C. When a small amount of MgO or -Fe2O3 or Al2O3 were added to the rice hull silica, the rice hull silica crystallized to cristobalite at 1500C. MgO, -Fe2O3 and Al2O3 diffused to silica as Mg2+, Fe3+ and Al3+ at high temperatures. These ions broke the SiO4 tetrahedron network, so that the amorphous state of rice hull silica was maintained. As sintering occurred at 1500C in rice hull silica mixed with additives such as MgO, the melting …

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Solid Particle Erosive Wear Behaviour Of Flame Sprayed Eva Based Polymeric Coatings, Ekrem Altuncu, Barış Önen Sep 2020

Solid Particle Erosive Wear Behaviour Of Flame Sprayed Eva Based Polymeric Coatings, Ekrem Altuncu, Barış Önen

Journal of Metals, Materials and Minerals

Flame spraying of polymers allows obtaining functional coatings for protecting against wear and corrosion. Among many engineering polymers, the Ethylene-Vinyl Acetate (EVA) copolymer attracts attention with its superior mechanical and chemical properties. EVA, which has high chemical resistance, high impact resistance and mechanical flexibility, high friction coefficient, is among the candidate coating material that can be used in aerospace, automotive, marine, chemical and manufacturing industries to protect metallic surfaces. The use of polymeric coatings in applications is often restricted when large surfaces need to be coated or if the coating needs to be applied in the openair field. Flame spraying …

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Open-Source Grinding Machine For Compression Screw Manufacturing, Jacob Franz, Joshua M. Pearce Sep 2020

Open-Source Grinding Machine For Compression Screw Manufacturing, Jacob Franz, Joshua M. Pearce

Michigan Tech Publications, Part 1

Some of the most promising distributed recycling and additive manufacturing (DRAM) technical systems use fused particle fabrication (FPF) or fused granular fabrication (FGF), where compression screws force post-consumer waste plastic through a heated nozzle for direct 3D printing. To assist the technical evolution of these systems, this study provided the details of an invention for a low-cost, easily replicable open-source grinding machine for compression screw manufacturing. The system itself can be largely fabricated using FPF/FGF following the self-replicating rapid prototyper (RepRap) methodology. This grinding machine can be made from a cordless cut-off grinder and < $155 in parts. The new invention is demonstrated to be able to cut custom screws with variable (i) channel depths, (ii) screw diameters, (iii) screw lengths, (iv) pitches, (v) abrasive disk thicknesses, (vi) handedness of the screws, (vii) and materials (three types of steel tested: 1045 steel, 1144 steel, and 416 stainless steel). The results show that the device is more than capable of replicating commercial screws as well as providing makers with a much greater flexibility to make custom screws. This invention enables the DRAM toolchain to become even more self-sufficient, which assists the goals of the circular economy.

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Preparation And Characterisation Of Heat Treated Oil Palm-Empty Fruit Bunch/High Density Polyethylene Composites, Nordin Nur Afifah Sep 2020

Preparation And Characterisation Of Heat Treated Oil Palm-Empty Fruit Bunch/High Density Polyethylene Composites, Nordin Nur Afifah

Student Works (2020-2029)

Natural fibre composites (NFCs) are composite materials, in which the reinforcing fibres are derived from renewable and carbon dioxide neutral resources such as wood or plants. NFC can be made by replacing synthetic fibres with various types of natural fibres. Oil palm empty fruit bunch (OPEFB) fibre and oil palm mesocarp fibre are two important types of fibrous materials left in the palm-oil industry. In this study, EFB will be used as a reinforcement to the high-density polyethylene (HDPE). EFB was heat-treated at 180°C using vacuum oven for one hour, extrusion compounded with HDPE at 10%, 20% and 30% weight …

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Schottky And Poole-Frenkel Conduction Mechanisms In Zron/Sic System, Lusus Vanessa Sep 2020

Schottky And Poole-Frenkel Conduction Mechanisms In Zron/Sic System, Lusus Vanessa

Student Works (2020-2029)

In this work, the conduction mechanisms of Schottky Emission (SE) and Poole–Frenkel (PF) Emission for the ZrON/SiC system with a temperature range between 400 oC to 900 oC were analyzed. Understanding of the conduction charge mechanisms will help to estimate leakage characteristics of the ZrON/SiC system. Based on the J-E plot measured at different temperatures for 15 minutes, the obtained r2 was ranged between 0.90–0.98, which confirmed the data obtained complied with the standard SE model. Furthermore, the data plotted from the Effective Barrier Height Extracted from the SE plot showed the highest values of

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Nonlinear Optical Measurements Of Cdsip2 At Near And Mid-Infrared Wavelengths, Manuel R. Ferdinandus, Jamie J. Gengler, Kent L. Averett, Kevin T. Zawilski, Peter G. Schunemann, Carl M. Liebig Sep 2020

Nonlinear Optical Measurements Of Cdsip2 At Near And Mid-Infrared Wavelengths, Manuel R. Ferdinandus, Jamie J. Gengler, Kent L. Averett, Kevin T. Zawilski, Peter G. Schunemann, Carl M. Liebig

Faculty Publications

We measure the birefringence of the nonlinear optical (NLO) properties of cadmium silicon phosphide via the Z-scan technique at near and mid-infrared wavelengths. We discuss the implications of the NLO properties on optical parametric amplifier performance. We find that the nonlinear absorption does reduce the conversion efficiency, while the nonlinear refraction has a negligible effect.

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Graphene Based Barrier Membrane For Gas Separation Processes, Cheng Peng Aug 2020

Graphene Based Barrier Membrane For Gas Separation Processes, Cheng Peng

Dissertations

Novel graphene oxide (GO) flake-based composite lamellar membrane structure is being developed as a potential component of a garment for protection against chemical warfare agents (CWAs) represented here by simulants, dimethyl methyl phosphonate (DMMP) (a sarin-simulant) and 2-chloroethyl ethyl sulfide (2-CEES) (a simulant for sulfur mustard), yet allowing a high moisture transmission rate. GO flakes of dimensions 300-800 nm, 0.7-1.2 nm thickness and dispersed in an aqueous suspension are formed into a membrane by vacuum filtration on a porous polyethersulfone (PES) or poly (ether-ether-ketone) (PEEK) support membrane for noncovalent π-π interactions with GO flakes. After physical compression of such a …

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Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan Aug 2020

Numerical Study Of Paraffin Wax Melting In A Cavity With A Gradient Of Hot Wall Inclination, Agus Dwi Korawan

Makara Journal of Technology

The melting of a phase change material (PCM) in a cavity with a gradient of hot wall inclination was simulated numerically using five models, namely, Model-A, Model-B, Model-C, Model-D, and Model-E with gradients of −2, −4, ∞, 4, and 2, respectively. The PCM was paraffin wax, which was melted using an enthalpy porosity technique with a pressure-based method. Model-A was found to be the best model. For the completion of the melting process, the models were assigned with the liquid fraction of 1. Model-A required the shortest time, followed by Model-B, Model-C, Model-E, and Model-D, respectively. Compared with Model-C, Model-A …

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