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Saterlie M.,Alfred University | Sahin H.,Advanced Materials and Devices | Kavlicoglu B.,Advanced Materials and Devices | Liu Y.,Advanced Materials and Devices | Graeve O.,Alfred University
Nanoscale Research Letters | Year: 2011

We present an analysis of the dispersion characteristics and thermal conductivity performance of copper-based nanofluids. The copper nanoparticles were prepared using a chemical reduction methodology in the presence of a stabilizing surfactant, oleic acid or cetyl trimethylammonium bromide (CTAB). Nanofluids were prepared using water as the base fluid with copper nanoparticle concentrations of 0.55 and 1.0 vol.%. A dispersing agent, sodium dodecylbenzene sulfonate (SDBS), and subsequent ultrasonication was used to ensure homogenous dispersion of the copper nanopowders in water. Particle size distribution of the copper nanoparticles in the base fluid was determined by dynamic light scattering. We found that the 0.55 vol.% Cu nanofluids exhibited excellent dispersion in the presence of SDBS. In addition, a dynamic thermal conductivity setup was developed and used to measure the thermal conductivity performance of the nanofluids. The 0.55 vol.% Cu nanofluids exhibited a thermal conductivity enhancement of approximately 22%. In the case of the nanofluids prepared from the powders synthesized in the presence of CTAB, the enhancement was approximately 48% over the base fluid for the 1.0 vol. % Cu nanofluids, which is higher than the enhancement values found in the literature. These results can be directly related to the particle/agglomerate size of the copper nanoparticles in water, as determined from dynamic light scattering. © 2011 Saterlie et al.


Grant
Agency: Department of Defense | Branch: Army | Program: STTR | Phase: Phase I | Award Amount: 93.24K | Year: 2013

This Small Business Technology Transfer (STTR) Phase I effort will demonstrate the feasibility of an innovative tungsten carbide (WC) metal matrix composite for use as a non-carcinogenic penetrator for armor piercing (AP) munitions for small arms. The objectives of this effort are to: 1) Mechanically compact the WC and binder powders, 2) Sinter the compacted powders into a fully dense composite, 3) Characterize the structure of the composite, 4) Characterize the physical properties of the composite, and 5) Produce a 5.56mm diameter, 500mm long rod with the proposed material. By successful completion of the Phase I project, a new material and processing technique, capable of producing high-performance AP penetrators, will be delivered.


Saterlie M.S.,Alfred University | Sahin H.,Advanced Materials and Devices | Kavlicoglu B.,Advanced Materials and Devices | Liu Y.,Advanced Materials and Devices | Graeve O.A.,Alfred University
Chemistry of Materials | Year: 2012

We present a study of powder agglomeration and thermal conductivity in copper-based nanofluids. Synthesis of the copper powders was achieved by the use of three different surfactants (polyvinylpyrrolidone, oleic acid, and cetyl trimethylammonium bromide). After careful determination of morphology and purity, we systematically and rigorously compared all three of the surfactants for the production of viable copper-based nanofluids using dynamic light scattering. Our results show that the use of surfactants during synthesis of copper nanopowders has important consequences on the dispersion of the powders in a base fluid. The oleic-acid-prepared powders consisted of small particles of ∼100 nm that did not change with the addition of dispersant. The CTAB-prepared powders exhibited the best dispersion characteristics, as they formed small particles of approximately 80 nm in the presence of SDBS. The thermal conductivity enhancement in our nanofluids exhibited a linear relationship with powder loading for an average particle size of ∼100 nm and similar particle size distributions that range from ∼50 to 650 nm, but independent of crystallite size and with all other factors maintained constant (surface area, surface additives, levels of oxidation) such that a 0.55 vol % loading results in a thermal conductivity enhancement of 22% over water and a 1.0 vol % loading results in a thermal conductivity enhancement of 48% over water. This study is the first to decouple the effect of a carefully characterized particle size distribution using dynamic light scattering versus crystallite size from X-ray line broadening on the thermal conductivity enhancement of a nanofluid. © 2012 American Chemical Society.


Cahill J.T.,University of California at San Diego | Ruppert J.N.,University of Nevada, Reno | Wallis B.,Advanced Materials and Devices | Liu Y.,Advanced Materials and Devices | And 2 more authors.
Langmuir | Year: 2014

We present the mechanisms of formation of mesoporous scandia-stabilized zirconia using a surfactant-assisted process and the effects of solvent and thermal treatments on the resulting particle size of the powders. We determined that cleaning the powders with water resulted in better formation of a mesoporous structure because higher amounts of surfactant were preserved on the powders after washing. Nonetheless, this resulted in agglomerate sizes that were larger. The water-washed powders had particle sizes of >5 μm in the as-synthesized state. Calcination at 450 and 600 °C reduced the particle size to ∼1-2 and 0.5 μm, respectively. Cleaning with ethanol resulted in a mesoporous morphology that was less well-defined compared to the water-washed powders, but the agglomerate size was smaller and had an average size of ∼250 nm that did not vary with calcination temperature. Our analysis showed that surfactant-assisted formation of mesoporous structures can be a compromise between achieving a stable mesoporous architecture and material purity. We contend that removal of the surfactant in many mesoporous materials presented in the literature is not completely achieved, and the presence of these organics has to be considered during subsequent processing of the powders and/or for their use in industrial applications. The issue of material purity in mesoporous materials is one that has not been fully explored. In addition, knowledge of the particle (agglomerate) size is essential for powder handling during a variety of manufacturing techniques. Thus, the use of dynamic light scattering or any other technique that can elucidate particle size is essential if a full characterization of the powders is needed for achieving postprocessing effectiveness. © 2014 American Chemical Society.


Sahin H.,Advanced Materials and Devices | Gordaninejad F.,University of Nevada, Reno | Wang X.,University of Nevada, Reno | Liu Y.,Advanced Materials and Devices
Journal of Intelligent Material Systems and Structures | Year: 2012

In this study, the response times of magnetorheological fluids and magnetorheological fluid valves are studied under various flow configurations. Two types of valving geometries, annular flow and radial flow, are considered in the magnetorheological fluid valve designs. The transient pressure responses of magnetorheological fluid valves are evaluated using a diaphragm pump with a constant volume flow rate. The performance of each magnetorheological valve is characterized using a voltage step input as well as a current step input while recording the activation electric voltage/current, magnetic flux density, and pressure drop as a function of time. The variation of the response time of the magnetorheological valves under constant volume flow rate is experimentally investigated. The Maxwell model with a time constant is employed to describe the field-induced pressure behavior of magnetorheological fluid under a steady flow. The results demonstrate that the pressure response times of the magnetorheological fluid and the magnetorheological valves depend on the designs of the electric parameters and the valve geometry. Magnetorheological valves with annular flow geometry have a slower falling response time compared to their rising response time. Magnetorheological valves with radial flow geometry demonstrate faster pressure response times both in rising and in falling states. © The Author(s) 2012.


Grant
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 125.00K | Year: 2016

NASA is planning to return to the moon in 2020 to explore thousands of miles of the moon?s surface with individual missions, lasting six months or longer. Surface mobility is critical to outpost buildup and exploration activities, where the change in the vehicle weight between unloaded and loaded cargo conditions and travel over rough terrain can adversely affect the ride handling conditions and vehicle dynamics. The vehicle suspension system components should accommodate for the required range of vehicle weights and provide mobility during various surface activities. In response to NASA?s need to improve surface mobility, an autonomously adaptive liquid spring/damper system is proposed. This system will utilize a compressible fluid, which performs as a liquid spring to eliminate the need for mechanical springs and accumulators, to reduce the overall weight and space requirements of the suspension. The controllable damping force will be utilized by a fluid system that has a fast response time. The system will provide independently controllable damping force on each wheel. Based on our prior work, the proposed system could have a weight saving of more than 20% and size saving of at least 40%. The proposed system is a fail-safe device, i.e., in case of any power interruption or electronic failure, it will retain as a regular passive suspension system component. In this effort, the feasibility of utilizing the proposed system will be demonstrated through testing and multi-body vehicle dynamics model analysis. The proposed system will increase the mobility of the exploration vehicle under different payload (cargo and possible crew) configurations.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 79.97K | Year: 2014

This Small Business Innovation Research (SBIR) Phase I effort will demonstrate the feasibility of a fail-safe reusable Forward Closure System (FCS) for use in underwater launch tubes. The proposed FCS will be reusable, fail-safe, scalable, capable of withstanding pressures, and have an opening time on the order of milliseconds, while protecting a payload from exposure to sea conditions. Multiple actuation methods and sealing methods will be designed, analyzed, and evaluated. The objectives of this effort are to: 1) Design reusable FCS concepts, 2) Evaluate the FCS designs through analysis, modeling, and simulation, 3) Perform a trade study for down selection, 4) Demonstrate that the requirements are met, and 5) Demonstrate operability to sub-scale laboratory bench testing. By successful completion of the project, a fail-safe reusable FCS design will be delivered along with analysis, simulations, and bench-testing results to show the feasibility for use in underwater launch tubes.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase I | Award Amount: 149.84K | Year: 2014

This SBIR Phase I and Phase I Option effort will demonstrate the feasibility of a controllable missile lateral support system that reacts automatically to shock and vibration inputs. The proposed design concept will utilize a smart material to provide automatically controllable shock and vibration damping for variable payload weights contained within the missile tube. Modeling and simulation will be conducted based on the system requirements and operational scenarios. A subscale conceptual design will be tested, evaluated, and delivered. Existing submarine shock and vibration isolation systems are passive systems that do not have the ability to accommodate changes in the payload. The proposed system will eliminated this drawback, since the damping will be adjusted based on the acceleration feedback provided to a control system. The proposed system will be sustainable and designed as fail-safe, where during a power supply interruption it will behave as a passive isolator.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 998.93K | Year: 2011

The focus of the Phase II project will be on design, fabrication, and testing of an adaptive vertical support group AVSG with an active shock and vibration control system (ASVCS) that can mitigate shock and vibrations and increase mission capability for and to support variable payload systems. The Phase II effort will be conducted on the AVSG mount, test fixture development, design and development of test elements, and testing. For Phase II Option I, the AVSG assembly will be designed, developed and tested with ASVCS to evaluate its performance. For Phase II Option II, the integration capability of the system with underwater launch platform interfaces will be studied through the engineering analysis.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 492.71K | Year: 2015

This SBIR Phase II effort will be aimed towards designing and testing a controllable missile lateral support system (LSS) that reacts automatically to shock and vibration inputs. A sub-scale lateral support system (LSS) assembly consisting of six jacking feet and a full-scale LSS jacking feet unit will be fabricated and tested. The electromechanically actuated LSS will offer controllable damping to protect the payload from shock and vibrations events, while having the capability of aligning the canister within the missile tube. The proposed design concept will utilize a smart material to provide automatically controllable shock and vibration damping for variable payload weights contained within the missile tube. In Phase II a control system will be developed for optimized performance of the scaled LSS and for integration with ship controls.

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