Density Based Fuzzy C Means Clustering to prolong Network Lifetime in Smart Grids

Wireless sensor networks (WSN's) are preferred for industrial applications due to progressive increase of sensor electronics. One such application is deployment of WSN's in smart grids. Smart Grid integrates information and communication techniques with electricity network. Smart grids utilize sophisticated control and monitoring devices for improving the efficiency of the grid. For energy efficient, low cost monitoring and control in smart grid WSN's is treated as a promising technology. Advanced Metering Infrastructure (AMI) is the key technology in the distribution networks of Smart Grid. The AMI is composed of various sensors for metering purpose. The meter data is also useful for the distribution operators to manage the demand response. The network involves smart meters, smart electric gas and water meters along with digital network management appliances for optimizing the electric network with real time data management. The smart sensors are limited in terms of battery, operational power and memory. These sensors communicate with the base station in restricted range. The communication between smart grid nodes and base station (sink) is multi-hop in nature. The communication takes place within limited range of communication so the security concerns that are involved in the network are to be handled by the routing protocols. So as to make the bidirectional communication efficient between the smart sensors and utility an effective routing scheme is required for these energy limited devices to handle the heavy network traffic in smart grids. Here energy efficient routing for WSN's in NAN networks to attain load balancing is proposed through density based Fuzzy C means clustering (DFCM). The obtained simulation results show that DFCM can provide a satisfactory performance for enhancing the network life span.

     

Application of active power sensitivity to frequency and voltage variations on load shedding

The occurrence of a large disturbance in a power system can lead to a decline in the system frequency and bus voltages due to a real and reactive power deficiency or due to the formation of islands with generation–load imbalance. Load shedding is an emergency control action that can prevent a blackout in the power system by relieving the overload in some parts of the system. This paper shows that rate of change of frequency can be utilized to determine the magnitude of generation–load imbalance, while the rate of change of voltage with respect to active power can be utilized to identify the sensitive bus for load shedding. The frequency, voltages and their rate of change can be obtained by means of measurements in real-time from various devices such as digital recorders or phasor measurement units or these parameters can be estimated from the voltage data by other means such as an optimal estimation method like Kalman filtering. The rate of change of system frequency, along with the equivalent system inertia may be used to estimate the magnitude of the disturbance prior to each load shedding step. The buses with a higher rate of change of voltage may be identified as the critical ones for load shedding and load can be first shed at these buses, depending on the change in the power flow at each bus. This application is tested on the IEEE 30 bus system and the preliminary results demonstrate that it is feasible to be used in load shedding to restore system voltage and frequency.     

Enhancement in Creep Strength of Modified 9CR–1MO Steel Through Thermo-Mechanical Treatment

In the present investigation, microstructure of the modified 9Cr–1Mo (T91) steel was refined through thermo-mechanical treatment (TMT). The finer precipitation of M₂₃C₆ and MX precipitates were observed in the TMT processed T91 steel. Creep deformation behaviour of T91 steel and TMT processed T91 steel was carried out at 923 K. The minimum creep rate of the TMT processed steel was significantly lowered as compared to T91 steel. The TMT processing of modified 9Cr–1Mo steel resulted in enhancement of creep strength due to presence of finer precipitates which relatively delayed the recovery of dislocation structure and coarsening of sub-boundaries than the steel in the normalized and tempered condition.     

A Novel Mouse Model of TGFβ2-Induced Ocular Hypertension Using Lentiviral Gene Delivery

Glaucoma is a multifactorial disease leading to irreversible blindness. Primary open-angle glaucoma (POAG) is the most common form and is associated with the elevation of intraocular pressure (IOP). Reduced aqueous humor (AH) outflow due to trabecular meshwork (TM) dysfunction is responsible for IOP elevation in POAG. Extracellular matrix (ECM) accumulation, actin cytoskeletal reorganization, and stiffening of the TM are associated with increased outflow resistance. Transforming growth factor (TGF) β2, a profibrotic cytokine, is known to play an important role in the development of ocular hypertension (OHT) in POAG. An appropriate mouse model is critical in understanding the underlying molecular mechanism of TGFβ2-induced OHT. To achieve this, TM can be targeted with recombinant viral vectors to express a gene of interest. Lentiviruses (LV) are known for their tropism towards TM with stable transgene expression and low immunogenicity. We, therefore, developed a novel mouse model of IOP elevation using LV gene transfer of active human TGFβ2 in the TM. We developed an LV vector-encoding active hTGFβ2^C226,228S under the control of a cytomegalovirus (CMV) promoter. Adult C57BL/6J mice were injected intravitreally with LV expressing null or hTGFβ2^C226,228S. We observed a significant increase in IOP 3 weeks post-injection compared to control eyes with an average delta change of 3.3 mmHg. IOP stayed elevated up to 7 weeks post-injection, which correlated with a significant drop in the AH outflow facility (40.36%). Increased expression of active TGFβ2 was observed in both AH and anterior segment samples of injected mice. The morphological assessment of the mouse TM region via hematoxylin and eosin (H&E) staining and direct ophthalmoscopy examination revealed no visible signs of inflammation or other ocular abnormalities in the injected eyes. Furthermore, transduction of primary human TM cells with LV_hTGFβ2^C226,228S exhibited alterations in actin cytoskeleton structures, including the formation of F-actin stress fibers and crossed-linked actin networks (CLANs), which are signature arrangements of actin cytoskeleton observed in the stiffer fibrotic-like TM. Our study demonstrated a mouse model of sustained IOP elevation via lentiviral gene delivery of active hTGFβ2^C226,228S that induces TM dysfunction and outflow resistance.     

Surface Modifications for Improved Delivery and Function of Therapeutic Bacteria

Live therapeutic bacteria (LTBs) hold promise to treat microbiome‐related diseases. However, few approaches to improve the colonization of LTBs in the gastrointestinal tract exist, despite colonization being a prerequisite for efficacy of many LTBs. Here, a modular platform to rapidly modify the surface of LTBs to enable receptor‐specific interactions with target surfaces is reported. Inspired by bacterial adhesins that facilitate colonization, synthetic adhesins (SAs) are developed for LTBs in the form of antibodies conjugated to their surface. The SA platform is nontoxic, does not alter LTB growth kinetics, and can be used with any antibody or bacterial strain combination. By improving adhesion, SA‐modified bacteria demonstrate enhanced in vitro pathogen exclusion from cell monolayers. In vivo kinetics of SA‐modified LTBs is tracked in the feces and intestines of treated mice, demonstrating that SA‐modified bacteria alter short‐term intestinal transit and improve LTB colonization and pharmacokinetics. This platform enables rapid formation of an intestinal niche, leading to an increased maximum concentration and a 20% improvement in total LTB exposure. This work is the first application of traditional pharmacokinetic analysis to design and evaluate LTB drug delivery systems and provides a platform toward controlling adhesion, colonization, and efficacy of LTBs.     

Corrosion behavior of SiC reinforced magnesium composites

The corrosion behavior of two SiC reinforced Mg-based metal matrix composites, Mg-6SiC and Mg-16SiC (in volume percent), has been studied in freely aerated 1 M NaCl solution and compared with that of pure Mg. The presence of SiC particles deteriorated the corrosion resistance of magnesium. Corrosion resistance decreased with increasing SiC volume fraction. The galvanic corrosion current density between pure SiC and pure Mg has been experimentally measured using zero resistance ammeter technique and theoretically determined using mixed potential theory. Galvanic corrosion between Mg matrix and SiC reinforcement in the composites did not contribute significantly to the overall corrosion rate. Electrochemical impedance spectroscopy indicated that the higher corrosion rates for the composites could be related to the defective nature of surface film.     

A novel parallel prefix adder for optimized Radix-2 FFT processor

Multidimensional Systems and Signal Processing - The Fast Fourier Transform (FFT) is the basic building block for DSP applications where high processing speed is the critical requirement. Resource...     

A frequency‐constrained geometric Pontryagin maximum principle on matrix Lie groups

We present a geometric discrete‐time Pontryagin maximum principle (PMP) on matrix Lie groups that incorporates frequency constraints on the control trajectories in addition to pointwise constraints on the states and control actions directly at the stage of the problem formulation. This PMP gives first‐order necessary conditions for optimality and leads to two‐point boundary value problems that may be solved by numerical techniques to arrive at optimal trajectories. We demonstrate our theoretical results with numerical simulations on the optimal trajectory generation of a wheeled inverted pendulum and an attitude control problem of a spacecraft on the Lie group SO(3).