Robb Winter

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Biomass combustion: Relationship between pollutant formation and fuel composition

Tappi Journal, 1989

A 65-kW refractory-walled reactor was used to study biomass combustion under conditions typical o... more A 65-kW refractory-walled reactor was used to study biomass combustion under conditions typical of the suspension-burning phase in a spreader-stoker-fired boiler. Isothermal combustion data and nitric oxide (NO) emission rates were obtained as a function of temperature, local oxygen concentration, and vertical velocity for sized biomass fuels. Two softwoods, a hardwood, and a North Carolina peat were studied

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Preparation of magnesium hydroxide surfaces as a model for flame retardant fillers

Mining, Metallurgy & Exploration, 1999

Three substrates (MgO crystal, CaF2 crystal and Mg plate) were used to construct thin layers of M... more Three substrates (MgO crystal, CaF2 crystal and Mg plate) were used to construct thin layers of Mg(OH)2. Various routes were used to modify these substrates, including surface hydration and sol-gel coating. In each case, it was found (by using Fourier transform infrared spectroscopy) that thin layers of Mg(OH)2 could be produced. In the case of hydrated layers, the surface morphology of the Mg(OH)2 resembles the bulk platelet shape of precipitated Mg(OH)2.

On the Data Aggregation Point Placement in Smart Meter Networks

2017 26th International Conference on Computer Communication and Networks (ICCCN)

A smart meter Neighborhood Area Network (NAN) is a significant component for smart grid. The dela... more A smart meter Neighborhood Area Network (NAN) is a significant component for smart grid. The delay- sensitive communication in NAN, such as the interaction of power system control signal, usually requires the maximum allowed delay in the order of a few milliseconds. Therefore, it is crucial to investigate how to shorten the latency and guarantee real-time communications. Since the location of Data Aggregation Points (DAPs) significantly affects the propagation latency between DAPs and their associated smart meters, in this paper, we aim at tackling the DAP placement problem in a delay-sensitive smart meter NAN. Specifically, the DAP placement problem is formulated first. Then, a network partition approach, termed Clustering-based DAP Placement (CDP), is proposed to solve the problem. Extensive simulations are conducted based on an actual neighborhood topology. The simulation results demonstrate that the proposed CDP is able to remarkably reduce the maximum propagation latency of data between DAP and their associated smart meters.

Evaluation of clustering algorithms for DAP placement in wireless smart meter network

2017 9th International Conference on Modelling, Identification and Control (ICMIC)

Wireless smart meter network has attracted extensive research interests for its capability on int... more Wireless smart meter network has attracted extensive research interests for its capability on intelligent control and monitor the power consumption in residential as well as commercial area. Wireless smart meter network constitutes with a number of smart meters to sense the electricity or gas consumption, data aggregation point (DAP) to collect data from smart meters, and utility center to gather all data from DAPs. In this work, we investigate the clustering and optimal DAP placement problem in the multi-hop smart meter network. Three representative clustering algorithms, namely k-means, self-organizing map, and fuzzy c-means, are evaluated and compared in terms of multi-hop shortest path distance (MSPD), size of clusters and computation complexity. Simulation results indicate that the hard assignment based methods, k-means and self-organizing, achieve similar performance whereas the soft assignment based fuzzy c-means falls behind with longer maximum MSPD and higher complexity.

In-Situ Cure Monitoring of the Immidization Reaction of PMR-15

Glass fiber reinforced polymer composites are becoming widely used in industry. With this increas... more Glass fiber reinforced polymer composites are becoming widely used in industry. With this increase in production, an in-situ method of quality control for the curing of the polymer is desirable. This would allow for the production of high-quality parts having more uniform properties.' Recently, in-situ fiber optic monitoring of polymer curing has primarily focused on epoxy resins and has been performed by Raman or fluorescence methods. In addition, some infrared (IR) investigations have been performed using transmission or ATR cells. An alternate IR approach involves using optical fibers as a sensor by utilizing evanescent wave spectroscopy.

Study of Angle & Distance Sensitivities for Presence Sensors in Smart Nanogrids

SoutheastCon 2018, 2018

Smart nanogrid technologies such as smart home and smart shelters are under development in the cu... more Smart nanogrid technologies such as smart home and smart shelters are under development in the current power and energy systems. In smart nanogrids, presence sensors play an essential role to detect human-being presence in room to control the operation of power devices like air conditioners automatically, and thus save power usage and electric bills. In this study, we field-tested the performance of X4M300 presence sensor for human-being detection and power device control. This presence sensor has a notable capability to detect living beings according to the movement of their breathing. In principle, this presence sensor is more reliable than PIR detectors, which are used to determine presence by using infrared light. For the presence sensor, the maximum range of detection is 10 meters, which can be adjusted by changing its settings via the Xethru explore software.

Data analysis and optimal specification of fuse model for fault study in power systems

2016 IEEE Power and Energy Society General Meeting (PESGM), 2016

In order to study the thermal energy in the process of fuse melting, data analysis is conducted o... more In order to study the thermal energy in the process of fuse melting, data analysis is conducted on the time/current curve provided by the manufacturer. Data analysis methodologies, such as sampling, variance analyze and residual sum of squares analyze, are performed in this process. These methods provide us the most optimal equation to describe the relationship between time, different level of fault current and the thermal energy that melts the fuse. A simulation fuse model is developed based on this result, and this model is tested in both DC and AC environment for verification purposes.

Probability Based Worn Circuit Breaker Modeling and Risk Evaluation on Potential Power Grid Failures

2017 IEEE 7th Annual International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER), 2017

Circuit breakers are one of the most commonly applied power protective devices, which are designe... more Circuit breakers are one of the most commonly applied power protective devices, which are designed to automatically isolate the circuit when the current exceeds a certain limit, to prevent the electric appliances from thermal damage. Circuit breakers can be manually or automatically reset after being tripped. With time elapsing, some mechanisms inside the circuit breakers may get aged and fatigued, and some connections and contacts may become loose and misaligned. The worn conditions may cause the circuit breaker failed to operate, or not able to trip within specified current and time range. These failures and malfunctions may cause discoordination in original power protection plan, and therefore cause unexpected partially or entirely blackout in the power grid. Some cyber attackers may even utilize this flaw to hack power appliances and breach the predefined power protective protocol. Due to the considerable number of circuit breakers in a power grid, simulation approach in system-...

Energy and fuel utilization of SiC-based 400V DC distribution network and 208V AC distribution network with distributed resources installation

Motivated by recent developments of wide-bandgap power semiconductor devices, renewable energy re... more Motivated by recent developments of wide-bandgap power semiconductor devices, renewable energy resources and smart grid, a 400V DC distribution network has a potential to replace the traditional 208V AC distribution network, in order to provide improved energy efficiency and advanced controllability, protection, sustainability and reliability in electric power system. In this paper, we analyzes the influences from a) novel wide-bandgap power converters; and b) distributed resources, e.g. solar, fuel cell, battery, etc., on the energy/fuel utilization (EFU) of 400Vdc distribution network and 208Vac distribution network. The efficiency gain and EFU are discussed and demonstrated by the system study of a 25.5kW distribution network. The study reveals that there is no side-effect but a little gain in EFU by using 400Vdc distribution network over 208Vac distribution network, even there is no distributed energy resource available. And the efficiency gain increases along with the amount of...

Sensitivity Studies of the Interfacial Shear Strength in Composite Materials Using the Microbond Test

Finite element analysis has been used to examine the microbond test of polymer matrix composite m... more

A Clustering Algorithm for the DAP Placement Problem in Smart Grid

In this paper, we investigate the DAP placement problem and propose solutions to reduce the dista... more In this paper, we investigate the DAP placement problem and propose solutions to reduce the distance between DAPs and smart meters. The DAP placement problem is formulated to two objectives, e.g., the average distance minimization and the maximum distance minimization. The concept of network partition is introduced in this paper and practical algorithms are developed to address the DAP placement problem. Extensive simulations are conducted based on a real suburban neighborhood topology. The simulation results verify that the proposed solutions are able to remarkably reduce the communication distance between DAPs and their associated smart meters.

Time-Dependent Response of Polymer Systems Under Cyclic Loading Conditions

Dynamic Failure in Composite Materials and Structures

The paper concerns the time dependent response of polymer systems subjected to superimposed stati... more The paper concerns the time dependent response of polymer systems subjected to superimposed static and cyclic loads. An experimental study of two materials, Nylon 6/6 and a piezoelectric polyvinylidene fluoride (PVDF)-based composite, has been conducted with the objective to determine the degree of cyclic creep effects depending on the mean stress, cyclic stress amplitude and frequency. Creep acceleration due to cyclic loading effects has been observed in both materials even in the range of stresses well below their respective viscoelastic linearity limits. It is clear that these effects are essentially nonlinear, as the response of the materials to cyclic loading conditions does not represent a simple superposition of the responses to static and fully reversed cyclic loads applied separately. An increase of creep rates in both polymers has been observed consistently as frequencies and amplitudes of vibration tended to increase. However, the relation between cyclic creep effects and...

Study of a 3kW high-efficient wide-bandgap DC-DC power converter for solar power integration in 400V DC distribution networks

2017 IEEE 12th International Conference on Power Electronics and Drive Systems (PEDS)

Direct current (DC) distribution network has a higher efficiency in energy delivery over alternat... more Direct current (DC) distribution network has a higher efficiency in energy delivery over alternative current (AC) network, when there is a high penetration of dc renewable energy resources and energy storage systems. In this paper, the energy conversion efficiency (n) of a 3kW Silicon Carbide (SiC)-based Boost Cascaded Buck-Boost power converter is analyzed for solar power integration in 400Vdc distribution networks, compared to a Silicon (Si)-based BoCBB prototype. We found that: 1) there is about 2% reduction in n when the switching frequency of MOSFETs increases from 20 kHz to 100 kHz in Si-based prototype. Comparatively, the efficiency reduction with SiC-based MOSFETs is limited within 1% in the same case; 2) under the same switching frequency, the n increases 2.4% in average by replacing Si MOSFETs with SiC MOSFETs. The differences in n increase along the switching frequency. In addition, the switching frequency of 50 kHz is optimal in overall system performance for SiC-based prototype, which makes a good tradeoff between high n, good power quality, and compact size. These conclusions are verified by theoretical analysis and experiment tests. The experiment tests demonstrated a high efficiency of 97% in peak in power conversion.

Probability-based circuit breaker modeling for power system fault analysis

2017 IEEE Applied Power Electronics Conference and Exposition (APEC)

Circuit breakers are widely applied in power system protection by interrupting fault current. Amo... more Circuit breakers are widely applied in power system protection by interrupting fault current. Among all types of circuit breakers, we focus on the modeling of thermal-magnetic circuit breakers in this paper. Data regression and curve fitting methodologies are employed to study the manufacturer's time/current data. A brand new simulation model that contains probability tools is developed to realistically describe the tripping characteristics, and a product failure rate is also considered to reflect possible circumstances in real-world application of the thermal-magnetic circuit breakers. A simulation testbed system is included for the purposes of illustration and validation.

Nanoscale characteristics of conditioning film development on photobioreactor materials: influence on the initial adhesion and biofilm formation by a cyanobacterium

Biofouling

Abstract Adsorption of conditioning films on a solid surface is the first step in the development... more Abstract Adsorption of conditioning films on a solid surface is the first step in the development of biofilms. With the goal of understanding the preliminary adhesion mechanisms of cyanobacteria on photobioreactor (PBR) materials to prevent biofouling, the physical changes occurring on PBR materials were investigated during the initial adhesion and biofilm formation by Anabaena sp. PCC 7120, a cyanobacterium that is genetically modified to produce linalool. Atomic force microscopy (AFM) revealed that the conditioning film deposition was in the form of spike-like structures on all the materials except PVC. The average heights (in the range 9 − 16 nm) of the conditioning films deposited on glass, PMMA, PC and HDPE were 11 to 20 times higher than on PVC at 96 h. The time dependent change in thickness of conditioning films correlated well with Anabaena cell attachment to the PBR materials. The rapid and significant colonization of Anabaena on glass within 48 h was consistent with the increase in thickness of the conditioning film within this time period. Lack of the conditioning film spike structures and no change in thickness of the conditioning films with time on the PVC together with comparatively delayed cell attachment and conditioning-film protein deposition on this material, indicated that the nanoscale spike structures on the other PBR materials may be accelerating the cell attachment process but are not a prerequisite for cell attachment. These results suggest that PVC should be explored further as an antifouling material for photobioreactors. The thickness of the conditioning films on glass measured by a scratch and scan method was in good agreement with the thickness values measured by an adhesive tape method, indicating that both these methods can be used for fast and reliable AFM thickness determination of bacterial conditioning films.

Conditioning film formation and its influence on the initial adhesion and biofilm formation by a cyanobacterium on photobioreactor materials

Biofouling

Abstract Although cyanobacteria are a common group of microorganisms well-suited to utilization i... more Abstract Although cyanobacteria are a common group of microorganisms well-suited to utilization in photobioreactors (PBRs), studies of cyanobacteria fouling and its prevention are scarce. Using a cyanobacterium, Anabaena sp. PCC 7120, which had been genetically modified to enhance linalool production, the formation of conditioning films and the effects of these on the physico-chemical surface properties of various PBR materials during initial adhesion and biofilm formation were investigated. The adhesion assay revealed that the overall attachment of Anabaena was substratum dependent and no correlation between the hydrophobicity/roughness of clean material and cell attachment was found. Surface hydrophilicity/hydrophobicity of all the materials changed within 12 h due to formation of conditioning films. ATR-FTIR spectroscopy revealed that the fractional change in protein deposition between 12 to 96 h was consistent with Anabaena cell attachment but polysaccharide deposition was material specific and did not correlate with cell attachment on the PBR materials. Also, the delay in conditioning film proteins on PVC and PTFE indicated that components other than proteins may be responsible for the decrease in contact angles on these surfaces within 12 h. This indicates the important role of the chemical nature of adsorbed conditioning films in determining the initial attachment of Anabaena to PBR materials. The lower rate of attachment of Anabaena on the hydrophilic surfaces (glass and PMMA) between 72 h to 96 h (regime 3) showed that these surfaces could potentially have low fouling characteristics at extended time scales and should be considered for further research.

Comparison of the electrokinetic behavior of silica and glasses

Composite Interfaces

Many previous researchers have used high surface area silica as a model substrate for glass. In t... more Many previous researchers have used high surface area silica as a model substrate for glass. In this study, the electrokinetic behavior of natural silica and glasses of various compositions have been measured. In all cases, the unmodified samples were found to have points-of-zero charge values between pH 2 and 3.3. Also, the electrokinetic behavior of the samples after the adsorption

An Effective AODV-based Flooding Detection and Prevention for Smart Meter Network

Procedia Computer Science

Abstract In this paper, we investigate flooding attack detection and prevention for smart meter n... more Abstract In this paper, we investigate flooding attack detection and prevention for smart meter networks. The default Ad hoc On-Demand Distance Vector (AODV) protocol is vulnerable to flooding attacks because intermediate meters forward packets blindly. To detect and prevent flooding attacks, we propose a new AODV-based routing protocol called FLOoding aWareness AODV (FLOW-AODV) considering both with and without Internet Protocol (IP) spoofing. If no IP spoofing exists, we modify the route request forwarding procedure by adding new features. The main idea is to enable one-hop neighboring meters to detect attackers by counting the received route requests from the same source. Specifically, when a meter receives a request, it first determines whether it is a one-hop neighbor to the source or not. If yes, the one-hop neighboring meter updates its request counter for every received request from that source. When the received requests exceed a predefined number (e.g., 2), it perceives the source as an attacker and just discards the following requests, so the flooding is avoided. In this way, the receiver can prevent flooding attacks when there is no IP spoofing from flooding attacker. If IP spoofing exists, the flooding attacker will hide its real IP address. In this case, we have extended our algorithm and included trustworthiness of each neighbor in the neighbor routing table. Extensive simulations are conducted in NS3 to evaluate the performance of FLOW-AODV. Results show that FLOW-AODV obtains considerably higher performance in terms of packet delivery ratio, and average delay compared with the default AODV routing protocol. In addition, the FLOW-AODV significantly improves network performance and eliminates congestion when multiple attackers are involved.

Data Aggregation Point Placement Problem in Neighborhood Area Networks of Smart Grid

Mobile Networks and Applications

A smart meter neighborhood area network is usually regarded as the last mile network, which plays... more A smart meter neighborhood area network is usually regarded as the last mile network, which plays a significant role for communications in smart grid. A neighborhood area network typically consists of smart meters and Data Aggregation Points (DAPs), which collect energy consumption or billing information from smart meters and forward the information to wide area network gateways via wireless communications. The location of DAPs significantly affects the distance and associated transmission routes between DAPs and smart meters. In this paper, we investigate the DAP placement problem and propose solutions to reduce the distance between DAPs and smart meters. Specifically, the DAP placement problem is formulated with two objectives, e.g., the average distance minimization and the maximum distance minimization. The concept of network partition is introduced in this paper and two associated algorithms are developed to address the DAP placement problem. Extensive simulations are conducted based on a real suburban neighborhood topology. The simulation results verify that the proposed solutions are able to remarkably reduce the communication distance between DAPs and their associated smart meters.