Mechanical Engineering Commons^™

Flow Distribution And Heat Transfer Coefficients Inside Gas Holes Discharging, Amirhossein Eshtiaghi

LSU Master's Theses

Fluid flow and heat transfer coefficient associated with flow inside short holes (L/D=1) discharging orthogonally into a crossflow was investigated experimentally and numerically for (Re) ̅ ranging from 0.5×105 to 2×105, and blowing ratio ranging from 1.3 to 3.2. The basic configuration studied consists of a feed tube with five orthogonally located gas holes. Four different hole configurations were studied. The transient heat transfer study employs an IR-camera to determine the local heat transfer coefficient inside each hole. Velocity measurements and numerical flow simulation were used to better understand the measured heat transfer distribution inside the hole. The Nusselt number …

Pdms Based Waveguides For Microfluidics And Eocb, Weiping Qiu

LSU Master's Theses

Due to the low cost, fast and ease of molding, PDMS has become one of the most popular materials for microfluidics devices, bioMEMS applications. Meanwhile, the integration of different functional components on to one single chip (or Lab on a Chip) is the dream for many scientists and engineers in the related area. In addition to the necessary mechanical components for accommodating the reactions, such as pumps, valves, mixers and so on, optical components such as waveguides, lens, interferers are all desired to be lumped into such a system.

The waveguide for such a system requires the material to have …

Low-Order Modeling Of Micro-Flier Impact With Thin Stationary Energetic Targets, Mark B. Fry

LSU Master's Theses

The impact of high-speed (500-1500 m/s), laser driven micro-fliers with thin energetic targets (10-100 &# 956;m) is being examined to characterize impact-induced heating and combustion of these materials. Aluminum fliers are propelled by a laser into a thin metallic target plate having a layer of energetic material deposited on its backside. Mass spectrometry is performed in vacuo on the energetic side to interrogate the shock-induced chemistry of the energetic material. It is important to ignite and possibly detonate the energetic material without perforation of the target plate avoiding contamination of the vacuum chamber. To guide development of these experiments, a …

Programming And Healing Temperature Effects On The Efficiency Of Confined Self-Healing Polymers, Yves Quentin Yougoubare

LSU Master's Theses

Shape memory polymers are smart materials capable of fixing a temporary shape and returning to their initial shape in response to an external stimulus. Since the discovery and acknowledgment of their importance in 1960s, shape memory polymers have been the subject of tremendous and continuous attention. In a previous study conducted on a biomimetic shape memory polymer (SMP), the ability of a self-healing composite to heal, and to repair and restore structural-length scale damage using a close-then-heal (CTH) self-healing mechanism was examined and validated. The present study is purposed with investigation of the effects on healing efficiencies of the variation …

Combinatorial Multi-Level Mold Inserts Using Micro Machining And X-Ray Lithography, Oblesh Jinka

LSU Master's Theses

The present technology advancement in biomedical, micro-electro-mechanical systems (MEMS) engineering, bio-MEMS, healthcare, etc. is driving the need to fabricate devices with multi-level, high aspect ratio and complex microstructures, which in turn requires high quality mold inserts with all these features. The present thesis is concentrated in fabricating a multi-level mold insert with complex quasi 3 dimensional micro structures with dimensions down to 10µm and aspect ratios greater than 30 using a process combination of micro milling with X-ray lithography. Therefore, in this study the main focus was to fabricate a high quality mold insert template, which can be electroplated to …

Towards The Development Of Biotin Carboxylase Driven Robotic Nanoswimmers, Rachel Yates

LSU Master's Theses

The objective of this research is to take the first step towards demonstrating the use of the enzyme biotin carboxylase (BC) as a biomolecular motor. BC is a homodimeric protein involved in fatty biosynthesis in all organisms. The conjecture is that BC can convert chemical energy into useful mechanical work via its conformation change, which acts as a fin or flexible oar producing nonreciprocal motion. To this end, we fabricate a proof-of-concept biomolecular machine driven by BC molecules, viz., a robotic nanoswimmer. This machine consists of a Janus-type nanosize silica particle, where one hemisphere is coated with an intermediate layer …

The Effect Of Elevated Water Content On Ethanol Combustion, Baine Bernard Breaux

LSU Master's Theses

Ethanol is currently being considered as a potential alternative to traditional fuels. However, the fuel offers a low return in terms of energy output per dollar invested when compared to fossil fuels. More than 1/3 of the cost associated with bio-ethanol production is devoted to distillation and water removal. This study seeks to validate the use of hydrous ethanol as a practical fuel to be used in lieu of fossil fuels or anhydrous ethanol. Success would reduce the production cost associated with ethanol fuel. Hydrous ethanol was burned in a swirl-stabilized combustor, air is introduced at a constant flow rate …

Characterizing Impact Induced Hot-Spot Morphology In Granular Solid Explosive, John Gilbert

LSU Master's Theses

Deformation induced ignition of heterogeneous solid explosives is believed to originate at hot-spots within the material which are local regions of elevated temperature resulting from dissipative mechanisms such as plastic deformation and inter-particle friction. Inert meso-scale modeling of these materials can principally account for hot-spot formation enabling the characterization of hot-spot size and temperature distributions which are important for ignition but are di_x000E_cult to experimentally resolve. The focus of this study is to characterize hot-spot morphology, as well as the distribution of hot-spots, behind quasi-steady compaction waves computed from predicted temperature fields resulting from numerical simulations of rigid planar piston …

Modeling Of Dynamics Of Gyroscopic Systems, Siddharth Sharma

LSU Master's Theses

The amplitude of vibrations of a rotating system operating near or at its critical speed grows without bound. This poses a serious problem for the rotating machinery industry from the perspective of design, maintenance, vibration troubleshooting and stability of the rotating equipments.

In this thesis, we wish to develop an exact method of analysis for the system of a mass-less symmetrical shaft rotating in symmetrical bearings (SSSB) with finite displacement at bearing end. The method so developed is expected to be extended to the SSSB model of a shaft having mass. The stability analysis is performed for both the systems. …

Numerical And Experimental Evaluation Of Preheated Premixed Flames At Lean And Rich Conditions, Joseph Edward Gibson

LSU Master's Theses

Preheating a combustible mixture enhances the laminar burning flux characteristic m_ad with high reaction firing rates. As a result, the flammable zone as defined by inlet conditions of equivalence ratio and temperature is expanded beyond that available at standard ambient conditions; however, fundamental questions in these combustion regimes have not been addressed. In this thesis, preheated lean and rich combustion of methane/air mixtures is studied numerically and experimentally to catalog and confirm expected trends in these regimes. Numerical simulations were completed using both GRI-Mech 3.0 and San Diego mechanisms in the combustion code Cantera. An adiabatic simulation data set …