Engineering Commons^™

Formation Of Organized Nanostructures From Unstable Bilayers Of Thin Metallic Liquids, Mikhail Khenner, Sagar Yadavali, Ramki Kalyanaraman

Mikhail Khenner

Dewetting of pulsed-laser irradiated, thin (< 20 nm), optically reflective metallic bilayers on an optically transparent substrate with a reflective support layer is studied within the lubrication equations model. A steady-state bilayer film thickness (h) dependent temperature profile is derived based on the mean substrate temperature estimated from the elaborate thermal model of transient heating and melting/freezing. Large thermocapillary forces are observed along the plane of the liquid-liquid and liquid-gas interfaces due to this h-dependent temperature, which, in turn, is strongly influenced by the h-dependent laser light reflection and absorption. Consequently the dewetting is a result of the competition between thermocapillary and intermolecular forces. A linear analysis of the dewetting length scales established that the non-isothermal calculations better predict the experimental results as compared to the isothermal case within the bounding Hamaker coefficients. Subsequently, a computational non-linear dynamics study of the dewetting pathway was performed for Ag/Co and Co/Ag bilayer systems to predict the morphology evolution. We found that the systems evolve towards formation of different morphologies, including core-shell, embedded, or stacked nanostructure morphologies.

From Pollen To Polyester, Debbie Chachra

Debbie Chachra

Polyester bees are all over the Northeast. The interesting thing about them is that they dig underground tunnels, about the width of your pinky finger, where they lay their eggs. To protect their larvae from heat, cold, fungus, bacteria and other dangers, the bees line these chambers with a clear, cellophanelike substance. The larvae then live underground for most of their lives in these reinforced cells.

State Dependent Properties Of Rail Pads, Sakdirat Kaewunruen, Alexander Remennikov

Alex Remennikov

Rail pad is one of the main components in ballasted railway track systems. It is inserted between the rail and the sleeper to attenuate dynamic wheel/rail interaction forces, preventing the underlying railway track components from excessive stresses. Generally, the dynamic design of tracks relies on the available data, which are mostly focused on the structural condition at a specific toe load. Recent findings show that track irregularities could significantly amplify the loads on railway tracks. This phenomenon gives rise to a concern that the rail pads may experience higher deterioration rate than anticipated in the past. On this ground, an …

Dynamic Properties Of Railway Track And Its Components : A State-Of-The-Art Review, Sakdirat Kaewunruen, Alexander Remennikov

Alex Remennikov

Recent findings indicate one of major causes of damages, which is attributed to the resonant behaviours, in a railway track and its components. Basically, when a railway track is excited to generalised dynamic loading, the railway track deforms and then vibrates for certain duration. Dynamic responses of the railway track and its components are the key to evaluate the structural capacity of railway track and its components. If a dynamic loading resonates the railway track’s dynamic responses, its components tend to have the significant damage from excessive dynamic stresses. For example, a rail vibration could lead to defects in rails …

Photolithographic Surface Micromachining Of Polydimethylsiloxane (Pdms), Weiqiang Chen, Raymond H. W. Lam, Jianping Fu

Weiqiang Chen

A major technical hurdle in microfluidics is the difficulty in achieving high fidelity lithographic patterning on polydimethylsiloxane (PDMS). Here, we report a simple yet highly precise and repeatable PDMS surface micromachining method using direct photolithography followed by reactive ion etching (RIE). Our method to achieve surface patterning of PDMS applied an O2 plasma treatment to PDMS to activate its surface to overcome the challenge of poor photoresist adhesion on PDMS for photolithography. Our photolithographic PDMS surface micromachining technique is compatible with conventional soft lithography techniques and other silicon-based surface and bulk micromachining methods. To illustrate the general application of our …

Ductile Regime Single Point Diamond Turning Of Quartz Resulting In An Improved And Damage-Free Surface, John Patten

john a patten

No abstract provided.

Response Characterization Of Electroactive Polymers As Mechanical Sensors, G. Alici, Geoffrey M. Spinks, J. D. Madden, Y. Wu, G G. Wallace

Gordon Wallace

The characterization of the dynamic response (including transfer function identification) of trilayer polypyrrole (PPy) type conducting polymer sensors is presented. The sensor was built like a cantilever beam with the free end stimulated through a mechanical lever system, which provided displacement inputs. The voltage generated and current passing between the two outer PPy layers as a result of the input was measured to model the output/input behavior of the sensors based on their experimental current/displacement and voltage/displacement frequency responses. We specifically targeted the low-frequency behavior of the sensor as it is a relatively slowsystem. Experimental transfer function models were generated …

Direct Pore‐Level Observation Of Permeability Increase In Two‐Phase Flow By Shaking, Igor A. Beresnev, William Gaul, R. Dennis Vigil

R. Dennis Vigil

Increases in permeability of natural reservoirs and aquifers by passing seismic waves have been well documented. If the physical causes of this phenomenon can be understood, technological applications would be possible for controlling the flow in hydrologic systems or enhancing production from oil reservoirs. The explanation of the dynamically increased mobility of underground fluids must lie at the pore level. The natural fluids can be viewed as two-phase systems, composed of water as the wetting phase and of dispersed non-wetting globules of gas or organic fluids, flowing through tortuous constricted channels. Capillary forces prevent free motion of the suspended non-wetting …

Thickness Of Residual Wetting Film In Liquid-Liquid Displacement, Igor A. Beresnev, William Gaul, R .Dennis Vigil

R. Dennis Vigil

Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic, …

Energy, Jane Qiong Zhang, Linda Vanasupa

Linda Vanasupa

This document is a set of learning materials to support the teaching of energy issues particularly related to sustainability in engineering. It is designed for the general engineering or science audience. Its design is based on the framework of the Fink Taxonomy of Significant Learning. The document is a fully-editable set of slides in open source format (pptx) that includes references to targeted learning objectives on each slide and annotations in the notes section of each slide.

Sustainable Development, Jane Qiong Zhang, Linda Vanasupa

Linda Vanasupa

This document is a set of learning materials to support the teaching of Sustainable Development issues particularly related to sustainability in engineering. It is designed for the general engineering or science audience. Its design is based on the framework of the Fink Taxonomy of Significant Learning. The document is a fully-editable set of slides in open source format (pptx) that includes references to targeted learning objectives on each slide and annotations in the notes section of each slide.

Hydrometallurgical Process For Extraction Of Metals From Electronic Waste-Part Ii: Development Of The Processes For The Recovery Of Copper From Printed Circuit Boards (Pcb), Zeljko J. Kamberovic

Zeljko J Kamberovic

Rapid technological development induces increase of generation of used electric and electronic equipment waste, causing a serious threat to the environment. Waste printed circuit boards (WPCBs), as the main component of the waste, are significant source of base and precious metals, especially copper and gold. In recent years, most of the activities on the recovery of base and precious metals from waste PCBs are focused on hydrometallurgical techniques as more exact, predictable and easily controlled compared to conventional pyrometallurgical processes. In this research essential aspects of the hydrometallurgical processing of waste of electronic and electrical equipment (WEEE) using sulfuric acid …

Optimization Of The Acoustic Performance Of Polyimide Foams, Olivier Doutres, Noureddine Atalla, Rebecca Wulliman, Shari Ferguson, Steve Bailey

Olivier Doutres Ph.D.

Due to their low weight, high fire resistance and good mechanical strength, SOLIMIDE® Polyimide foams are good candidates for sound packages in aerospace sound transmission applications. However, their high resistance to airflow limits the sound absorption efficiency inside a double wall structure and thus the sound transmission loss of the structure. The paper discusses two concepts to improve the transmission efficiency of such materials for double wall applications: (i) improving its sound absorption behavior by removing mechanically or chemically the cell membranes and thus decreasing both the flow resistance and tortuosity, (ii) coupling the Polyimide foams to screens (porous or …

A Practical Impedance Tube Method To Estimate The Normal Incidence Sound Transmission Loss Of Double Wall Structure, Olivier Doutres, Noureddine Atalla

Olivier Doutres Ph.D.

The objective of this paper is to propose a practical impedance tube method to optimize the sound transmission loss of double wall structure by concentrating on the sound package placed inside the structure. In a previous work, the authors derived an expression that breaks down the transmission loss of a double wall structure containing a sound absorbing blanket separated from the panels by air layers in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The sound transmission loss …

Forced Instability Of Core-Annular Flow In Capillary Constrictions, Igor A. Beresnev, William Gaul, R. Dennis Vigil

R. Dennis Vigil

Instability of fluid cylinders and jets, a highly nonlinear hydrodynamic phenomenon, has fascinated researchers for nearly 150 years. A subset of the phenomenon is the core-annular flow, in which a non-wetting core fluid and a surrounding wall-wetting annulus flow through a solid channel. The model, for example, represents the flow of oil in petroleum reservoirs. The flow may be forced to break up when passing through a channel’s constriction. Although it has long been observed that the breakup occurs near the neck of the constriction, the exact conditions for the occurrence of the forced breakup and its dynamic theory have …

Purely Electronic Switching With High Uniformity, Resistance Tunability, And Good Retention In Pt-Dispersed Sio2 Thin Films For Reram, Albert Chen

Albert B Chen

Resistance switching memory operating by a purely electronic switching mechanism, which was first realized in Pt-dispersed SiO2 thin films, satisfies criteria including high uniformity, fast switching speed, and long retention for non-volatile memory application. This resistive element obeys Ohm's law for the area dependence, but its resistance exponentially increases with the film thickness, which provides new freedom to tailor the device characteristics.

The Effects Of Humidity On The Dielectric Response In Ferroelectric Polymer Films Made By Langmuir-Blodgett Deposition, Kristin Kraemer, Alexander Sorokin, Christina Othon, Stephen Ducharme, Vladimir Fridkin

Christina M Othon

No abstract provided.

Electron Irradiation Effects On Ferroelectric Copolymer Langmuir-Blodgett Films, Christina M. Othon, Stephen Ducharme

Christina M Othon

The effect of irradiation on the ferroelectric properties of Langmuir-Blodgett films of the copolymer poly(vinylidene fluoride-trifluorethelene) is investigating using 1.26 MeV electrons with dosages from 16 to 110 Mrad. Irradiation causes a systematic decrease in the phase transition temperature, coercive field and polarization of these thin films.

Transferts De Chaleur Dans Un Réacteur Thermochimique Solaire Muni D’Un Récepteur Volumique Poreux, Hernando Romero Paredes Rubio

Hernando Romero Paredes Rubio

Un réacteur thermochimique solaire de 1 kW muni d’une structure céramique poreuse en céramique est modélisé pour simuler les transferts thermiques a l’intérieur du récepteur volumétrique. Le modèle développé a été utilisé pour prévoir le comportement thermique du réacteur en fonction des différentes conditions opératoires qui concernent le débit de gaz inerte, le flux solaire incident, la porosité, la longueur du récepteur, et la prise en compte de réactions chimiques. Les résultats montrent que la température maximale est de 1850K pour une concentration solaire de 1000 soleils. La température diminue de manière significative lorsque le débit de gaz augmente. Un …

Pigments For Improving Plant Health In Organic Systems, Gregory Keith Bartley Jr.

Gregory Keith Bartley Jr.

Photosynthesis, arguably the most important biological process on earth, solely relies on the ability of pigments to capture, utilize, and convert the sun‟s energy to form life. The adequate conversion of light into harvestable food, fuel, and fiber regulates rates of population and economic growth. In order to meet the expanding needs of humanity with the earth‟s potential for agricultural production, new sustainable techniques for increased photosynthetic efficiency in plants must be implemented. The earth's pattern of light exposure is extremely dynamic, exhibiting constant changes in quantity and quality throughout time and space. For photosynthetic organisms, this meant evolving various …

Literature Review - Pigments In Plant Health, Gregory Keith Bartley Jr.

Gregory Keith Bartley Jr.

The solar radiation received at the Earth’s surface helps power the photochemical processes in photosynthesis. However, under sunlight, photosynthetic organisms are unavoidably exposed to potentially harmful levels of ultraviolet and visible light radiation. Consequently, plants have developed many mechanisms for the avoidance and dissipation of excess light energy. The growth of crops under increased solar irradiance during sub- and supra-optimal temperature conditions is an obstacle for increasing seasonal crop production in the transition zone. New methods for reducing the photoinhibitory effects of solar irradiation have been observed in the field of turfgrass. Through the application of pigment compounds to the …

Effect Of Thermal Stabilizers Composed Of Zinc Barbiturate And Calcium Stearate For Rigid Poly(Vinyl Chloride).Pdf, Shumin Li

Shumin Li

A Large Deformation, Rotation-Free, Isogeometric Shell, D. J. Benson, Y. Bazilevs, Ming-Chen Hsu, T. J. R. Hughes

Ming-Chen Hsu

Conventional finite shell element formulations use rotational degrees of freedom to describe the motion of the fiber in the Reissner–Mindlin shear deformable shell theory, resulting in an element with five or six degrees of freedom per node. These additional degrees of freedom are frequently the source of convergence difficulties in implicit structural analyses, and, unless the rotational inertias are scaled, control the time step size in explicit analyses. Structural formulations that are based on only the translational degrees of freedom are therefore attractive. Although rotation-free formulations using C0 basis functions are possible, they are complicated in comparison to their C1 …

A Size-Dependent Nanoscale Metal–Insulator Transition In Random Materials, Albert Chen, Soo Gil Kim, Yudi Wang, Wei-Shao Tung, I-Wei Chen

Albert B Chen

Insulators and conductors with periodic structures can be readily distinguished, because they have different band structures, but the differences between insulators and conductors with random structures are more subtle. In 1958, Anderson provided a straightforward criterion for distinguishing between random insulators and conductors, based on the 'diffusion' distance ζ for electrons at 0 K (ref. 3). Insulators have a finite ζ, but conductors have an infinite ζ. Aided by a scaling argument, this concept can explain many phenomena in disordered electronic systems, such as the fact that the electrical resistivity of 'dirty' metals always increases as the temperature approaches 0 …

Porosity Reduction Model In Titanium– Hydroxyapatite Fgm Composites Using Shrinkage Measurement, Ahmed A. Madfa

Ahmed A. Madfa

A multilayered titanium (Ti)–hydroxyapatite (HA) functionally graded material was produced via pressureless sintering at 1100uC. The initial and final porosities were determined via shrinkage measurements. The final porosity verification was carried out by the Archimedes method. The experimental porosity measurements were compared with two proposed models. The macroscopic and microstructure features and the measured porosities confirmed that the volume fraction porosity was associated with both matrix and reinforcing particles in all cases. The percolation threshold was observed at x50?75 in the xTiz(12x)HA mixture.

Cryogenic Technique For Processing Steel Treatment, Ajit Behera

Ajit Behera

Cryogenics or deep freezing have been around for quite some time. There is documented research from as far back as the 1930’s where German companies used it on components of jumbo aircraft engines. Cryogenic processing had its US origins in the 1940s. Cold treatments or sub zero treatments are done to make sure there is no retained austenite during quenching. Cryogenics is a relatively new process and to eliminate retained austenite, the temperature has to be lowered, but one that using correct procedures can bring substantial economic benefits. In cryogenic treatment the material is to be deep freeze temperatures of …

Demand On Magic Metal, Ajit Behera

Ajit Behera

No abstract provided.

Preparation And Characterisation Of Graft Biopolymer To Improve Sustained Release Property, Ajit Behera

Ajit Behera

In the present piece of research work focuses on grafting Acrylic acid with HPMC to obtain copolymers with improved properties, biodegradable and biocompatible that will be used as hydrogel or water absorbing polymers. To develop a prolong release activity drug delivery system for the medication purpose to enhance drug activity and reduce the frequency of dose via this hydrogel. A novel HPMC-g- acrylic acid hydrogel was prepared by in-situ emulsifier free emulsion polymerization using benzyl peroxide as an initiator through 1-stage grafting. Acrylic Acid could intercalate into layers of HPMC and form graft composites through in situ graftpolymerization with acrylic …

The Natural Composite: Spheroidal Graphite Iron, Ajit Behera

Ajit Behera

The conventional materials are nowadays not sufficient to cater to the variety of uses and exposure to various environments that may take place while they are put into use. Hence this leads to the development of composites, which nearly suffice the above two conditions. Composite material is a material composed of two or more distinct phases (matrix phase and reinforcing phase) and having bulk properties significantly different from those of any of the constituents. In this developing age for iron industry there is large demand for spherodial Graphite iron (S.G. Iron). S.G. Iron also known as a composite in which …

Characterisation Of Nanoparticle Through Sem, Ftir, Xrd & Dsc, Ajit Behera

Ajit Behera

Nanoparticles are widely due as Sustained Release Drug Delivery System. Due to their smaller size of controlled drug release potential, targeting ability, enhancement of therapeutic efficacy and reduction of toxicity. Nifedipine one of the calcium channel blocker use for the management of hypertension. Spray drier technique develops Nifedipine loaded nanoparticle. Primary superimulsion phase contains Drug (Nifedipine), Polymer (Ethylcellulose) & suitable non-aqueous Solvent (Dichloromethane) which are sprayed over secondary phase containing aqueous solvent with dispersing polymers (PVA) are prepared by taking drug to polymer weight ratio of 20:90. Formation of films on the surface of secondary phase dried, sieved & forward …