Nanoscience and Nanotechnology Commons^™

Advances In Cellulose Nanomaterial-Based Foams For Environmental Applications, Md Musfiqur Rahman

Electronic Theses and Dissertations

The use of metal-oxide nanoparticles adsorbents is limited to fixed-bed columns in industrial-scale water treatment applications. This limitation is commonly attributed to the tendency of nanoparticles to aggregate, the use of non-sustainable and inefficient polymeric resins as supporting materials, or a lack of adsorption capacity. Foams and aerogels derived from cellulose nanomaterials have unique characteristics, such as high porosity and low density, which enables their use in a variety of environmental applications, including water treatment. However, the overall use of cellulose nanomaterial-based foams in various environmental sectors is limited due to the high cost of production associated with time- and …

Micro And Nano R2r Embossing Of Extruded Polymers, Raymond S. Frenkel

Doctoral Dissertations

This dissertation presents a process for directly imprinting or embossing extruded polymers as an advancement in roll-to-roll (R2R) embossing methods that avoids the problems of converting preformed films, increases throughput, and reduces costs. A proof-of-concept R2R apparatus was designed and constructed for directly embossing extruded polymer, and experimental results were evaluated. This laboratory scale R2R apparatus employed a thin metal ribbon belt mold with micro or nano scale features in a calendering setup, with a close coupled induction heating (IH) coil to preheat the ribbon mold above glass transition temperature (T_g) of the polymer, prior to contact with …

Characterization Of Materials Properties In Additively Manufactured Aisi-420 Martensitic Steel Deposited By Laser Engineered Net Shaping, Md Mehadi Hassan

Nanoscience and Microsystems ETDs

Metal additive manufacturing (AM) is a disruptive technology enabling the fabrication of complex and near-net-shaped parts by adding material layer-wise. It offers reduced lead production time. AM processes are finding applications in many industrial sectors such as aerospace, automotive, biomedical, and mold tooling. Despite the tremendous advantages of AM, some challenges still prevent this technology's adoption in high-standard applications. Anisotropy and inhomogeneity in the mechanical properties of the as-built parts and the existence of pores and lack-of-fusion defects are considered the main issues in directed energy deposition (L-DED) parts. Laser-engineered net shaping LENS® offers excellent possibilities to fabricate metal tools …

Influence Of Nano-Sized Sic On The Laser Powder Bed Fusion Of Molybdenum, Nathan E. Ellsworth, Ryan A. Kemnitz, Cayla C. Eckley, Brianna M. Sexton, Cynthia T. Bowers, Joshua R. Machacek, Larry W. Burggraf

Faculty Publications

Consolidation of pure molybdenum through laser powder bed fusion and other additive manufacturing techniques is complicated by a high melting temperature, thermal conductivity and ductile-to-brittle transition temperature. Nano-sized SiC particles (0.1 wt%) were homogeneously mixed with molybdenum powder and the printing characteristics, chemical composition, microstructure, mechanical properties were compared to pure molybdenum for scan speeds of 100, 200, 400, and 800 mm/s. The addition of SiC improved the optically determined density and flexural strength at 400 mm/s by 92% and 80%, respectively. The oxygen content was reduced by an average of 52% over the four scan speeds analyzed. Two mechanisms …

Silver Microparticle And Submicron Wire - Polylactic Acid Composites For Additive Manufacturing, Jenna W. Robichaux

University of New Orleans Theses and Dissertations

This thesis explores the incorporation of silver microparticle and submicron wire additives into thermoplastic filament feedstock for fused filament fabrication (FFF) to create multifunctional three-dimensional (3D) printable composites. The impact of silver microparticle and submicron wire additives on mechanical behavior along with antibacterial effect of the silver microparticle and submicron wire additives on printed objects were assessed.

Composite FFF filaments were fabricated by solution processing, granulation, and extrusion. Differential Scanning Calorimetry (DSC) was conducted to measure the glass transition and melting point temperatures of the composite filaments for 3D printing. The effect of the additive addition on the thermal properties …

Modulating Mechanical Properties Of Polymer Composites Via Colloidal Particle Reinforcement, Yusheng Guo

LSU Master's Theses

Additive manufacturing allows the rapid process of complex objects with excellent design flexibility. However, the products often exhibit poor mechanical properties when pure polymer is applied as printable material. In this work, we demonstrate that printability of polymer can be dramatically improved when particle filler is added to form reinforced polymer composites. Furthermore, the interaction between filler and polymer matrix leads to the enhancement in mechanical properties of the printed product. The material reinforcement induced by addition of fillers enables the wide application of polymer composites to print structures with unique features. In the printing of silica-reinforced pNIPAM composite, we …

3d Printing Of Iron Oxide Incorporated Polydimethylsiloxane Soft Magnetic Actuator, Rasoul Bayaniahangar

Dissertations, Master's Theses and Master's Reports

Soft actuators have grown to be a topic of great scientific interest recently. As the fabrication of soft actuators with conventional microfabrication methods are tedious, expensive, and time consuming, employment of 3-D printing fabrication methods appears promising as they can simplify fabrication and reduce the production cost. Complex structures can be fabricated with 3-D printing such as helical coils can achieve actuation performances that otherwise would not be possible with simpler geometries. In this thesis development of soft magnetic helical coil actuators of iron-oxide embedded polydimethylsiloxane (PDMS) was achieved with embedded 3-D printing techniques. Composites with three different weight ratios …

Additive Manufacturing Of High Performance Flexible Thermoelectric Generators Using Nanoparticle Inks, Tony Valayil Varghese

Boise State University Theses and Dissertations

Flexible thermoelectric devices are attractive power sources for the growing demand of flexible electronics and sensors. Thermoelectric generators have an advantage due to no moving parts, silent operation and constant power production with a thermal gradient.

Conventional thermoelectric devices are rigid and fabricated using complex and relatively costly manufacturing processes, presenting a barrier to increase the market share of this technology. To overcome such barriers, this work focuses on developing near ambient-temperature flexible thermoelectric generators using relatively low-cost additive manufacturing processes. A screen printable ink was developed for transforming nanoparticle ink into high-performance flexible thermoelectric generators with a peak thermoelectric …

Differential Mobility Classifiers In The Non-Ideal Assembly, Thamir Alsharifi

Theses and Dissertations

The differential mobility classifier (DMC) is one of the core components in electrical mobility particle sizers for sizing sub-micrometer particles. Designing the DMC requires knowledge of the geometrical and constructional imperfection (or tolerance). Studying the effects of geometrical imperfection on the performance of the DMC is necessary to provide manufacturing tolerance and it helps to predict the performance of geometrically imperfect classifiers, as well as providing a calibration curve for the DMC. This thesis was accomplished via studying the cylindrical classifier and the parallel plate classifier. The numerical model was built using the most recent versions of COMSOL Multiphysics^{® …}

High Strain Rate Dynamic Response Of Aluminum 6061 Micro Particles At Elevated Temperatures And Varying Oxide Thicknesses Of Substrate Surface, Carmine Taglienti

Masters Theses

Cold spray is a unique additive manufacturing process, where a large number of ductile metal micro particles are deposited to create new surface coatings or free-standing structures. Metallic particles are accelerated through a gas stream, reaching velocities of over 1 km/s. Accelerated particles experience a high-strain-rate microscopic ballistic collisions against a target substrate. Large amounts of kinetic energy results in extreme plastic deformation of the particles and substrate. Though the cold spray process has been in use for decades, the extreme material science behind the deformation of particles has not been well understood due to experimental difficulties arising from the …

Nanotextured Titanium Surfaces For Implants: Manufacturing And Packaging Aspects, Sachin Bhosle

Dissertations, Master's Theses and Master's Reports

It has been shown that nanotexturing the surface of otherwise smooth titanium orthopedic materials increases osteoblast proliferation in vitro, and the bone-implant contact area and pullout force in vivo. However, this prior work has not focused on the requirements for scale-up to industrial processes. This dissertation reports on titanium surface modifications by electrochemical anodization using a benign NH₄F electrolyte, and a hybrid electrolyte also containing AgF, rather than hazardous hydrofluoric acid used elsewhere. Nanotube fabrication of Ti6Al4V foils, rods, thermal plasma sprayed commercial implants, and laser and e-beam melted powder materials was demonstrated.

It was found …

Studies Of Periodic And Quasiperiodic Gold Nanohole Arrays And Their Applications, Zhaoliang Yang

Electronic Thesis and Dissertation Repository

Wavelength to refractive index sensitivity and resonance wavelength position are two very important performance characteristics for nanohole array based surface plasmon resonance sensors while these characteristics are mostly researched on periodic nanohole arrays, instead of quasiperiodic nanohole arrays. This thesis deduces theoretical equations about the wavelength to refractive index sensitivity and resonance wavelength position of quasiperiodic nanohole arrays. Theoretical analysis shows that wavelength to refractive index sensitivity is not associated with geometry pattern, hole size or pitch but with the wavelength. A novel surface plasmon resonance platform is built by transferring gold films patterned with quasiperiodic nanohole arrays to the …

Micro-Mechanical Assessment Of The Local Plastic Strain Invoked During A Splined Mandrel Flow Forming Operation, Meysam Haghshenas

Electronic Thesis and Dissertation Repository

Splined Mandrel Flow Forming (SMFF) is a metal spinning operation that involves the application of high multiaxial compressive stress states to invoke large plastic flow in the work piece. This allows for essentially one-step fabrication of complex internally-splined shapes. In this research project, the equivalent plastic strain, invoked throughout bcc (1020 steel) and fcc (5052 and 6061 aluminum alloys, pure copper, and 70/30 brass) samples, that were made by SMFF, was measured. The objective of the research were to measure the to obtain data on the effect of microstructure and mechanical parameters on the flow formability of ductile bcc and …

Characterization Of Conducting-Polymer-Based Bimorph Vibration Sensors, Weihua Li, Geoffrey M. Spinks, Lianbin Zhao, Yanzhe Wu, Dezhi Zhou, G G. Wallace

Professor Weihua Li

This paper presents theoretical and experimental investigation of mechanical-electrical properties of conducting polymers based bimorph sensors. A material parameter, hCP , is proposed to represent linear relationship between induction charge and the applied external deformation. Based on this assumption, a constitutive equation for bimorph sensors under steady-state external loadings are constructed and then solved. Mechanical-electrical properties of bimorph sensors are experimentally studied using both vibration-amplitude sweep mode and frequency sweep mode. The material parameter hCP , is identified by comparing theoretical analysis and experimental results. The applications of conducting polymers based bimorph sensors in smart structures are also discussed.

The Design And Fabrication Of A Microfluidic Reactor For Synthesis Of Cadmium Selenide Quantum Dots Using Silicon And Glass Substrates, Peter Robert Gonsalves

Master's Theses

A microfluidic reactor for synthesizing cadmium selenide (CdSe) quantum dots (QDs) was synthesized out of a silicon wafer and Pyrex glass. Microfabrication techniques were used to etch channels into the silicon wafer. Holes were wet-drilled into the Pyrex glass using a diamond-tip drill bit. The Pyrex wafer was anodically bonded to the etched silicon wafer to enclose the microfluidic reactor. Conditions for anodic bonding were created by exposing the stacked substrates to 300V at ~350oC under 5.46N of force. A syringe containing a room temperature CdSe solution was interfaced to the microfluidic reactor by using Poly (dimethylsiloxane) (PDMS) as an …

The Applications And Limitations Of Printable Batteries, Matthew Delmanowski

Graphic Communication

This study focuses on the potential applications for printed batteries and how they could affect the printing industry. It also analyzes the main problems associated with manufacturing this technology and what needs to be done to overcome these issues. To find the answers to these questions, two methods of research were used. The first was through the elite and specialized interviewing of Dr. Scott Williams of Rochester Institute of Technology and Professor Nancy Cullins from Cal Poly. The second form of research was a common, yet useful, method called secondary research. This entailed looking at recent written research papers about …

Static Friction And Surface Roughness Studies Of Surface Micromachined Electrostatic Micromotors Using An Atomic Force/Friction Force Microscope, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

A technique to measure the static friction forces (stiction) encountered in surface micromachined micromotors using a commercial atomic force microscope (AFM)/friction force microscope has been developed and is described. An AFM tip is pushed against a rotor arm of the micromotor so as to generate lateral deflection (torsion) of the tip, which is measured by the AFM. The maximum value of the lateral deflection obtained prior to rotor movement (rotation) is a measure of the static friction force of the micromotors. This technique was employed to study the effect of humidity and rest time on the static friction force of …

Development Of A Continuous Microscratch Technique In An Atomic Force Microscope And Its Application To Study Scratch Resistance Of Ultrathin Hard Amorphous Carbon Coatings, Sriram Sundararajan, Bharat Bhushan

Sriram Sundararajan

A method to measure friction during scratching at linearly increasing loads in a commercial atomic force/friction force microscope (AFM/FFM) has been developed. The normal load was increased in small increments over the required range for the scratch using a software module while the friction signal was measured via a breakout box and data acquisition computer. Topography images of the scratch were obtained in situ with the AFM in tapping mode with minimal loss of damage event information. This technique was employed to study the scratch resistance of hard amorphous carbon coatings of thicknesses ranging from 20 nm down to 3.5 …