Water Droplet Condensation on Lubricant-Infused Surfaces in a Vacuum Chamber

The infused lubricant on lubricant infused surfaces (LISs) creates the ideal properties for heat transfer condensation due to its chemically homogenous and atomically flat surface. The purpose of this independent study project was to continue the research on lubricant-infused surfaces to find the optimal oil film thickness for condensation. The optimal oil film thickness is determined by its water transfer rate, with reasonable thermal resistance and high droplet mobility to achieve high heat transfer performance. A lot of time was spent designing, building, and testing the vacuum chamber where this experiment will be conducted. The vacuum chamber will take in water vapor from the vapor generator and the vacuum pump will remove any noncondensable gases from the chamber and also decrease the saturation pressure and temperature within the vacuum chamber, causing condensation at lower temperatures. Cooling water will be transferred into the chamber from an external source through the cold plate that will hold the LIS samples, and the condensation on the LIS samples will be observed through the observation window using a camera placed outside of the chamber. We finished all the setup and initial testing, but due to time constraints, the actual experiment itself has been delayed. Next steps include making final modifications on the vacuum chamber and conducting condensation experiments within the vacuum chamber to find the optimal oil film thickness. This experiment will help optimize the conditions for the condensation of water droplets

Improving the Vertical Accuracy of Indoor Positioning for Emergency Communication

The emergency communication systems are undergoing a transition from the PSTN-based legacy system to an IP-based next generation system. In the next generation system, GPS accurately provides a user's location when the user makes an emergency call outdoors using a mobile phone. Indoor positioning, however, presents a challenge because GPS does not generally work indoors. Moreover, unlike outdoors, vertical accuracy is critical indoors because an error of few meters will send emergency responders to a different floor in a building. This paper presents an indoor positioning system which focuses on improving the accuracy of vertical location. We aim to provide floor-level accuracy with minimal infrastructure support. Our approach is to use multiple sensors available in today's smartphones to trace users' vertical movements inside buildings. We make three contributions. First, we present the elevator module for tracking a user's movement in elevators. The elevator module addresses three core challenges that make it difficult to accurately derive displacement from acceleration. Second, we present the stairway module which determines the number of floors a user has traveled on foot. Unlike previous systems that track users' foot steps, our stairway module uses a novel landing counting technique. Third, we present a hybrid architecture that combines the sensor-based components with minimal and practical infrastructure. The infrastructure provides initial anchor and periodic corrections of a user's vertical location indoors. The architecture strikes the right balance between the accuracy of location and the feasibility of deployment for the purpose of emergency communication

Finding 9-1-1 Callers in Tall Buildings

Accurately determining a user’s floor location is essential for minimizing delays in emergency response. This paper presents a floor localization system intended for emergency calls. We aim to provide floor-level accuracy with minimum infrastructure support. Our approach is to use multiple sensors, all available in today’s smartphones, to trace a user’s vertical movements inside buildings. We make three contributions. First, we present a hybrid architecture for floor localization with emergency calls in mind. The architecture combines beacon-based infrastructure and sensor-based dead reckoning, striking the right balance between accurately determining a user’s location and minimizing the required infrastructure. Second, we present the elevator module for tracking a user’s movement in an elevator. The elevator module addresses three core challenges that make it difficult to accurately derive displacement from acceleration. Third, we present the stairway module which determines the number of floors a user has traveled on foot. Unlike previous systems that track users’ foot steps, our stairway module uses a novel landing counting technique

Fast Run-Based Connected Components Labeling for Bitonal Images

Connected Components Labeling (CCL) is a fundamental task in binary image processing. Since its introduction in the sixties, several algorithmic strategies have been proposed to optimize its execution time. Most CCL algorithms in literature, including the current state-of-the-art, are designed to work on an input stored with 1-byte per pixel, even if the most memory-efficient format for a binary input only uses 1-bit per pixel. This paper deals with connected components labeling on 1-bit per pixel images, also known as 1bpp or bitonal images. An existing run-based CCL strategy is adapted to this input format, and optimized with Find First Set hardware operations and a smart management of provisional labels, giving birth to an efficient solution called Bit-Run Two Scan (BRTS). Then, BRTS is further optimized by merging pairs of consecutive lines through bitwise OR, and finding runs on this reduced data. This modification is the basis for another new algorithm on bitonal images, Bit-Merge-Run Scan (BMRS). When evaluated on a public benchmark, the two proposals outperform all the fastest competitors in literature, and therefore represent the new state-of-the-art for connected components labeling on bitonal images

NetServ: Reviving Active Networks

In 1996, Tennenhouse and Wetherall proposed active networks, where users can inject code modules into network nodes. The proposal sparked intense debate and follow-on research, but ultimately failed to win over the networking community. Fifteen years later, the problems that motivated the active networks proposal persist. We call for a revival of active networks. We present NetServ, a fully integrated active network system that provides all the necessary functionality to be deployable, addressing the core problems that prevented the practical success of earlier approaches. We make the following contributions. We present a hybrid approach to active networking, which combines the best qualities from the two extreme approaches — integrated and discrete. We built a working system that strikes the right balance between security and performance by leveraging current technologies. We suggest an economic model based on NetServ between content providers and ISPs. We built four applications to illustrate the model

NetServ Framework Design and Implementation 1.0

Eyeball ISPs today are under-utilizing an important asset: edge routers. We present NetServ, a programmable node architecture aimed at turning edge routers into distributed service hosting platforms. This allows ISPs to allocate router resources to content publishers and application service pro\-vi\-ders motivated to deploy content and services at the network edge. This model provides important benefits over currently available solutions like CDN. Content and services can be brought closer to end users by dynamically installing and removing custom modules as needed throughout the network. Unlike previous programmable router proposals which focused on customizing features of a router, NetServ focuses on deploying content and services. All our design decisions reflect this change in focus. We set three main design goals: a wide-area deployment, a multi-user execution environment, and a clear economic benefit. We built a prototype using Linux, NSIS signaling, and the Java OSGi framework. We also implemented four prototype applications: ActiveCDN provides publisher-specific content distribution and processing; KeepAlive Responder and Media Relay reduce the infrastructure needs of telephony providers; and Overload Control makes it possible to deploy more flexible algorithms to handle excessive traffic

Deswelling Mechanisms of Surface-Grafted Poly(NIPAAm) Brush: Molecular Dynamics Simulation Approach

Technologies ranging from solvent extraction and drug delivery to tissue engineering are beginning to benefit from the unique ability of “smart polymers” to undergo controllable structural changes in response to external stimuli. The prototype is poly(N-isopropylacrylamide) (P(NIPAAm)) which exhibits an abrupt and reversible hydrophilic to hydrophobic transition above its lower critical solution temperature (LCST) of ∼305 K. We report here molecular dynamics simulations to show the deswelling mechanisms of the hydrated surface-grafted P(NIPAAm) brush at various temperatures such as 275, 290, 320, 345, and 370 K. The deswelling of the P(NIPAAm) brush is clearly observed above the lower critical solution temperature below which the P(NIPAAm) brush is associated with water molecules stably. By simulating the poly(acrylamide) brush as a reference system having the upper critical solution temperature (UCST) behavior with the same conditions employed in the P(NIPAAm) brush simulations, we confirmed that the deswelling of P(NIPAAm) brush does not take place at a given range of temperatures, which validates our simulation procedure. By analyzing the pair correlation functions and the coordination numbers, we found that the dissociation of water from the P(NIPAAm) brush occurs mainly around the isopropyl group of the P(NIPAAm) above the LCST because of its hydrophobicity. We also found that the NH of the amide group in NIPAAm does not actively participate in the hydrogen bonding with water molecules because of the steric hindrance caused by the attached isopropyl group, and thereby the hydrogen bonding interactions between amide groups and water molecules are significantly weakened with increasing temperature, leading to deswelling of the hydrated P(NIPAAm) brush above the LCST through favorable entropic change. These results explain the experimental observations in terms of a simple molecular mechanism for polymer function

Enhanced ceramides production by Lactobacillus rhamnosus IDCC 3201 and its proposed mechanism

The use of probiotics has been applied for a variety of fields (e.g., immune system, mental health, and heart). In this study, the feasibility of lysates from L. rhamnosus IDCC 3201 for cosmetic ingredients was evaluated. More specifically, enhanced ceramides production in human epidermal keratinocytes by the lysates and its proposed machanism were investigated through in vitro and genome analysis. In results, enhanced spingomyelinase activity and thereby increased ceramides production by the lysates from L. rhamnosus IDCC 3201 was observed. Furthermore, it was found that the existence of glucosylceramdase in L. rhamonsus IDCC 3201 was attributed to enhanced ceramides production. Finally, it was verified that the lysates from L. rhamonsus IDCC 3201 was regarded as safe for its use as cosmetic materials. Thus, these findings have significant implications that might lead to the development of functional and safe cosmetic products from probiotics.Ceramides Glucosylceramidase Probiotics Skin health Sphingomyelinas