Development of differential electrochemical mass spectrometry (DEMS) technique for electrocatalysis studies

The initial target was to develop an electrocatalyst for electrochemical reduction of CO2 to selectively produce ethylene. An in-situ mass spectrometric technique namely Differential Electrochemical Mass Spectrometry (DEMS) was used for the study. Majority time was spent on CO2 reduction. Various strategies have been explored including alloy catalysts, modified Cu electrodes, increasing CO2 solubility using monoethanolamine solutions, ionic liquids to bypass the high activation energy requiring pathway and using guanidinium salts to stabilize intermediates. During the CO2 reduction project, certain limitations were felt using the DEMS technique which includes no control of/ low CO2 supply to electrocatalyst and inability to detect non-volatile products like formic acid. So in the thesis project Development of DEMS technique for electrocatalysis studies , the identified limitations of DEMS technique were eliminated to fulfill the CO2 reduction experiment requirements. An enhanced version of DEMS was developed by integrating capabilities of enhancement and control of reactant supply to the electrocatalyst by using an impinging jet and detection of non-volatile products produced using an additional electrochemical ring detector

High Rate Detection of Volatile Products Using Differential Electrochemical Mass Spectrometry: Combining an Electrode-Coated Membrane with Hydrodynamic Flow in a Wall-Tube Configuration

We present an experimental system that combines differential electrochemical mass spectrometry with hydrodynamic flow consisting of an impinging jet in a wall-tube configuration. This assembly allows simultaneous detection of electrochemical signals along with monitoring of dissolved gas species using differential electrochemical mass spectrometry under well-defined hydrodynamic conditions and over a wide range of mass transfer rates. The working electrode is deposited directly onto a thin, hydrophobic membrane, which also serves as the inlet to the mass spectrometer. This inlet provides extremely rapid mass detection as well as a high flux of products from the electrode surface into the mass spectrometer. The impinging jet is designed in a wall-tube configuration, in which the jet diameter is large compared to the electrode diameter, thus providing uniform and rapid mass transfer conditions over the entirety of the electrode surface. This combination of rapid detection and controllable flow conditions allows a wide range of hydrodynamic conditions to be accessed with simultaneous electrochemical and mass spectrometric detection of dissolved gas species, which is important in the analysis of a range of electrochemical reactions. The capabilities of this configuration are illustrated using a platinum-coated electrode and several electrochemical reactions, including ferrocyanide oxidation, proton reduction, and oxalic acid oxidation

SURVEY ON PERSONAL MOBILE COMMERCE PATTERN MINING AND PREDICTION

Abstract-Data Mining refers to extracting or "mining" knowledge from large amounts of data. In this paper we focus on Personal Mobile Commerce Pattern Mining and Prediction. Pattern mining is used to discover patterns to represent the relations among items. Prediction is important in intelligent environment, it captures repetitive patterns or activities and also helps in automating activities. This paper gives a brief introduction to various algorithms and a detailed study has been performed

Effect of composition on the structure of lithium- and manganese-rich transition metal oxides

The choice of chemical composition of lithium- and manganese-rich transition metal oxides used as cathode materials in lithium-ion batteries can significantly impact their long-term viability as storage solutions for clean energy automotive applications. Their structure has been widely debated: conflicting conclusions drawn from individual studies often considering different compositions have made it challenging to reach a consensus and inform future research. Here, complementary electron microscopy techniques over a wide range of length scales reveal the effect of lithium-to-transition metal-ratio on the surface and bulk structure of these materials. We found that decreasing the lithium-to-transition metal-ratio resulted in a significant change in terms of order and atomic-level local composition in the bulk of these cathode materials. However, throughout the composition range studied, the materials consisted solely of a monoclinic phase, with lower lithium content materials showing more chemical ordering defects. In contrast, the spinel-structured surface present on specific crystallographic facets exhibited no noticeable structural change when varying the ratio of lithium to transition metal. The structural observations from this study warrant a reexamination of commonly assumed models linking poor electrochemical performance with bulk and surface structure

Proximity-based attacks in wireless sensor networks

The nodes in wireless sensor networks (WSNs) utilize the radio frequency (RF) channel to communicate. Given that the RF channel is the primary communication channel, many researchers have developed techniques for securing that channel. However, the RF channel is not the only interface into a sensor. The sensing components, which are primarily designed to sense characteristics about the outside world, can also be used (or misused) as a communication (side) channel. In our work, we aim to characterize the side channels for various sensory components (i.e., light sensor, acoustic sensor, and accelerometer). While previous work has focused on the use of these side channels to improve the security and performance of a WSN, we seek to determine if the side channels have enough capacity to potentially be used for malicious activity. Specifically, we evaluate the feasibility and practicality of the side channels using today's sensor technology and illustrate that these channels have enough capacity to enable the transfer of common, well-known malware. Given that a significant number of modern robotic systems depend on the external side channels for navigation and environment-sensing, they become potential targets for side-channel attacks. Therefore, we demonstrate this relatively new form of attack which exploits the uninvestigated but predominantly used side channels to trigger malware residing in real-time robotic systems such as the iRobot Create. The ultimate goal of our work is to show the impact of this new class of attack and also to motivate the need for an intrusion detection system (IDS) that not only monitors the RF channel, but also monitors the values returned by the sensory components.MSCommittee Chair: Raheem A. Beyah; Committee Member: Ayanna M. Howard; Committee Member: Henry L. Owe

Development of differential electrochemical mass spectrometry (DEMS) technique for electrocatalysis studies

The initial target was to develop an electrocatalyst for electrochemical reduction of CO2 to selectively produce ethylene. An in-situ mass spectrometric technique namely Differential Electrochemical Mass Spectrometry (DEMS) was used for the study. Majority time was spent on CO2 reduction. Various strategies have been explored including alloy catalysts, modified Cu electrodes, increasing CO2 solubility using monoethanolamine solutions, ionic liquids to bypass the high activation energy requiring pathway and using guanidinium salts to stabilize intermediates. During the CO2 reduction project, certain limitations were felt using the DEMS technique which includes no control of/ low CO2 supply to electrocatalyst and inability to detect non-volatile products like formic acid. So in the thesis project "Development of DEMS technique for electrocatalysis studies", the identified limitations of DEMS technique were eliminated to fulfill the CO2 reduction experiment requirements. An enhanced version of DEMS was developed by integrating capabilities of enhancement and control of reactant supply to the electrocatalyst by using an impinging jet and detection of non-volatile products produced using an additional electrochemical ring detector.</p