Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Applied sciences (6)
- Pure sciences (6)
- Anaerobic digestion (1)
- Autogenous shrinkage (1)
- Biological nutrient removal (1)
-
- Cement hydration (1)
- Food waste (1)
- High-performance concrete (1)
- High-purity gallium (1)
- Inductively coupled plasma mass spectrometry (1)
- Lactic acid enantiomers (1)
- Mobility (1)
- Molecular beam epitaxy (1)
- Multi-valent ions (1)
- Optimization of fermentation (1)
- Photovoltaics (1)
- Purification (1)
- Solar cells (1)
- Superabsorbent polymer (1)
- Swelling kinetics (1)
- Thin films (1)
- Two dimensional electron gas (1)
- Publication
Articles 1 - 10 of 10
Full-Text Articles in Engineering
High-Purity Gallium Analysis By Inductively Coupled Plasma Mass Spectrometry, Kyungjean Min
High-Purity Gallium Analysis By Inductively Coupled Plasma Mass Spectrometry, Kyungjean Min
Open Access Theses
The mobility of Two-dimensional Electron Gas in AlGaAs/GaAs heterostructures that are grown in the Molecular Beam Epitaxy (MBE) can be increased by purification of the gallium used to grow the films. To attain 200 million cm2/Vs mobility, the impurity concentration of gallium should be reduced to below 1 ppb. The commercial 7N (99.99999%) gallium with 100 ppb total impurity is currently used in the MBE at Purdue University and is being purified by zone refining. To evaluate the commercial 7N gallium and establish the methodology for the impurity measurement after zone refining, germanium, iron, and zinc in 6N and 7N …
Identifying Conditions To Optimize Lactic Acid Production From Food Waste, Raymond M. Redcorn
Identifying Conditions To Optimize Lactic Acid Production From Food Waste, Raymond M. Redcorn
Open Access Theses
There is an increased demand for lactic acid for the production of biopolymers and to aid nutrient removal in wastewater treatment. Food waste offers a source of soluble sugars to produce lactic acid, which does not increase land demand, but digestion conditions have yet to be optimized when co-digested with primary sludge. Food waste was collected from cafeteria waste bins, homogenized and seeded with primary sludge. A Box Behnken Response surface design was used to optimize lactic acid production based on pH, temperature, loading rate, and retention time. Subsequent experiments verified and refined those conditions to optimize for both yield …
Impact Of Nanostructure On Polymer-Based Nonvolatile Memory Devices, Seung Hyun Sung
Impact Of Nanostructure On Polymer-Based Nonvolatile Memory Devices, Seung Hyun Sung
Open Access Theses
Memory functionality is essential for many high-end electronic applications (e.g. , smart phones, personal computers). Particularly, organic nonvolatile memory devices based on polymer ferroelectric materials are a promising approach toward the development of low-cost memory due to the ease of processing and flexibility associated with the device. Here, we will focus on a memory device with a two-component active layer and a diode structure. This ferroelectric diode (FeD) has a nanostructured active layer, composed of ferroelectric and semiconducting polymers, and it can provide easy access to high-performance polymer-based memory devices. In order to create these nanostructured active layers, we …
Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan
Open Access Theses
The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …
Physical And Chemical Attributes Of A Genetically Modified Fruit Pectin, Carl Patrick Littrell
Physical And Chemical Attributes Of A Genetically Modified Fruit Pectin, Carl Patrick Littrell
Open Access Theses
Pectin is an important polymer used in the food industry as a thickening and gelling agent. Though pectin is ubiquitous in plants, chemical and structural differences among pectin molecules prevent most from being viable for industrial use. Enzymes found naturally in fruit cell walls during the ripening process impair many desirable attributes of fruit pectins, rendering them unsuitable for industrial applications. Pectin methylesterase (PME) is one such enzyme whose expression can be altered during ripening through the use of recombinant genetic engineering. Reduction in levels of PME results in increased degree of methylation and molecular size of pectin, greatly increasing …
Preparation & Characterization Of High Purity Cu2 Znsn(Sxse1-X)4 Nanoparticles, Bethlehem G. Negash
Preparation & Characterization Of High Purity Cu2 Znsn(Sxse1-X)4 Nanoparticles, Bethlehem G. Negash
Open Access Theses
Research in thin film solar cells applies novel techniques to synthesize cost effective and highly efficient absorber materials in order to generate electricity directly from solar energy. Of these materials, copper zinc tin sulfoselenide (Cu2ZnSn(SxSe1-x) 4) nanoparticles have shown great promise in solar cell applications due to optimal material properties as well as low cost & relative abundance of materials.1,2 Sulfoselenide nanoparticles have also a broader impact in other industries including electronics3, LED 4, and biomedical research5. Of the many routes of manufacturing these class of semiconductors, …
Fundamental Studies On Copper Zeolites For Catalytic No X Abatement, Anuj Arun Verma
Fundamental Studies On Copper Zeolites For Catalytic No X Abatement, Anuj Arun Verma
Open Access Dissertations
Stringent regulations in mobile NOx emissions have resulted in the development of Standard Selective Catalytic Reduction (SCR) as the dominant NOx abatement technology in lean burn diesel engines. Standard SCR is a reaction of nitric oxide (NO) with ammonia (NH3), in the presence of oxygen (O 2) to form nitrogen (N2) and water (H2O). Copper containing zeolites show commercially viable SCR performance. Cu-SSZ-13 (CHA framework), a member of this family, is a preferred catalyst for SCR applications because it shows exceptional hydrothermal stability in addition to commercially viable SCR performance. Our work focuses …
Synthesis And Characterization Of Crystalline Iron Nanoparticles From Zerovalent Iron Sandwich Complexes, Anh Tue Nguyen
Synthesis And Characterization Of Crystalline Iron Nanoparticles From Zerovalent Iron Sandwich Complexes, Anh Tue Nguyen
Open Access Theses
In this project we present a systematic study on the synthesis of crystalline iron nanocubes by thermal decomposition of an iron sandwich complex, ( π-C5H5)Fe0(π-C 6H7), in the presence of oleylamine and oleylamine.HCl as surfactants and n-decane as a solvent. The presence of oleylamine.HCl is essential for the reproducible formation of crystalline iron cores.^ Reaction parameters such as temperature, surfactant concentration, effect of counterion, and organoiron reagent structure were investigated in order to obtain iron nanoparticles with uniform size and shape. The nanoparticles, which were characterized by …
The Development Of 6.7% Efficient Copper Zinc Indium Selenide Devices From Copper Zinc Indium Sulfide Nanocrystal Inks, Brian Kemp Graeser
The Development Of 6.7% Efficient Copper Zinc Indium Selenide Devices From Copper Zinc Indium Sulfide Nanocrystal Inks, Brian Kemp Graeser
Open Access Theses
As solar cell absorber materials, alloys of CuIn(S,Se)2 and Zn(S,Se) provide an opportunity to reduce the usage of indium along with the ability to tune the band gap. Here we report successful synthesis of alloyed (CuInS2 )0.5(ZnS)0.5 nanocrystals by a method that solely uses oleylamine as the liquid medium for synthesis. The reactive sintering of a thin film of these nanocrystals via selenization at 500 °C results in a uniform composition alloy (CuIn(S,Se)2 )0.5 (Zn(S,Se)) 0.5 layer with micron size grains. Due to the large amount of zinc in the film, the sintered grains exhibit the zinc blende structure instead …
Effect Of Multivalent Ions On The Swelling And Mechanical Behavior Of Superabsorbent Polymers (Saps) For Mitigation Of Mortar Autogenous Shrinkage, Qian Zhu
Open Access Theses
The chemical and physical structure-property relationships of model superabsorbent polymer (SAP) hydrogels were characterized with respect to swelling behavior and mechanical properties in different ionic solutions (Na+ , Ca2+ , and Al3+ ). The model hydrogels were composed of poly(sodium acrylate-acrylamide) (PANa-PAM) copolymer with varying concentrations of PANa (0, 17, 33, 67, and 83 wt.%) and covalent crosslinking densities of 1, 1.5, and 2 wt.%. By synthesizing the hydrogels in-house, systems with independently tunable amounts of covalent crosslinking and anionic functional groups were created, allowing for the relative effects of covalent and ionic crosslinking on the properties of the hydrogels …