Subcyclic Switching and Symmetrical Chopper with Tap Changing

Dual-Tap Chopping Stabilizer is an AC voltage regulator with dual tap changer. AC regulators based on tap changers are implemented with SCR’s and TRIACs are widely used for their robustness. With thyristor soft switching, commutation losses are reduced to nearly zero, but it allows only supercyclic commutation, i.e, only one commutation per cycle is possible. By replacing thyristors with high power transistors and gate turn off thyristors, it is possible to achieve several tap changes in one half cycle ,i.e, subcyclic commutation. In this paper an AC chopper is designed with MOSFET switches to achieve subcyclic commutation. Thus subcyclic switching is achieved. A freewheeling circuit is added in the load side. The freewheeling circuit has the following advantages

CLOUD SECURITY AND COMPLIANCE - A SEMANTIC APPROACH IN END TO END SECURITY

The Cloud services are becoming an essential part of many organizations. Cloud providers have to adhere to security and privacy policies to ensure their users' data remains confidential and secure. Though there are some ongoing efforts on developing cloud security standards, most cloud providers are implementing a mish-mash of security and privacy controls. This has led to confusion among cloud consumers as to what security measures they should expect from the cloud services, and whether these measures would comply with their security and compliance requirements. We have conducted a comprehensive study to review the potential threats faced by cloud consumers and have determined the compliance models and security controls that should be in place to manage the risk. Based on this study, we have developed an ontology describing the cloud security controls, threats and compliances. We have also developed an application that classifies the security threats faced by cloud users and automatically determines the high level security and compliance policy controls that have to be activated for each threat. The application also displays existing cloud providers that support these security policies. Cloud consumers can use our system to formulate their security policies and find compliant providers even if they are not familiar with the underlying technology

Organically templated three-dimensional open-framework metal selenites with a diamondoid network

Three-dimensional open-framework metal selenites of the formula, [H2N(CH2)4NH2]0.5[M(HSeO3)(Se2O5)] (M=Zn, Co or Ni), containing both selenite and diselenite units and intersecting 10-membered channels, have been prepared hydrothermally in the presence of piperazine. The compounds are isomorphous and crystallize in the P-1 space group. The structure is built up of MO6 dimers along with Se2O5 and HSeO3 units, the first two forming sheets, which are connected by the selenite units to yield a three-dimensional non-interpenetrating diamondoid network. The 10-membered channels have an unusual structure, being formed by 4-membered (M2Se2) and 6-membered (M2Se4) rings

Electric Field Analysis of Breast Tumor Cells

An attractive alternative treatment for malignant tumors that are refractive to conventional therapies, such as surgery, radiation, and chemotherapy, is electrical-pulse-mediated drug delivery. Electric field distribution of tissue/tumor is important for effective treatment of tissues. This paper deals with the electric field distribution study of a tissue model using MAXWELL 3D Simulator. Our results indicate that tumor tissue had lower electric field strength compared to normal cells, which makes them susceptible to electrical-pulse-mediated drug delivery. This difference could be due to the altered properties of tumor cells compared to normal cells, and our results corroborate this

Plant protection through RNAi: Alternative for pesticides and chemical approaches to pest control

RNA interference (RNAi) has become a powerful genetic approach to systemically dissect gene function on a genome wide scale. Double stranded RNA (dsRNA) mediated gene silencing has been proven as a potential approach to control several insect pests including fruit fly, nematode, cotton bollworm, and corn rootworm. RNA interference (RNAi) induced by hairpin RNAs are new line of defence against coleopteran and lepidopteron pests. It was shown that insect larvae fed with plant material expressing dsRNA for the insect genes triggered the RNAi pathway in insect larvae and blocked the expression of target genes. The resulting reduction in larval growth and subsequent death has opened up new options for insect control involving the insect genes perse. Hence, protein targets for insect control strategies can be minimized or completely ignored. Prospecting for novel resistance mechanisms depend on the plant generating an effective form of double-stranded RNA in the absence of an endogenous target gene without detrimental effect to itself. Although the amazing popularity of RNAi as a biotechnology tool is certainly justified, the underlying biology is still being worked out and the relative advantages and disadvantages of the approach are being efficiently addressed using emerging Bioinformatic tools and many genome sequences. In this review we would like to highlight the attempts of pest control using gene silencing or RNAi technology, few strategies, target genes for RNAi in insects, target site of action, and probable likely targets for RNAi in insects and plants for potential durable pest resistance mechanisms. © 2011 by Nova Science Publishers, Inc. All rights reserved

Tomorrow's Surgery: Micromotors and Microrobots

Surgical procedures have changed radically over the last few years due to the arrival of new technology. What will technology bring us in the future? This paper examines a few of the forces whose timing are causing new ideas to congeal from the fields of artificial intelligence, robotics, micromachining and smart materials. Intelligence systems for autonomous mobile robots can now enable simple insect level behaviors in small amounts of silicon. These software breakthroughs coupled with new techniques for microfabricating miniature sensors and actuators from both silicon and ferroelectric families of materials offer glimpses of the future where robots will be small, cheap and potentially useful to surgeons. In this paper we relate our recent efforts to fabricate piezoelectric micromotors in an effort to develop actuator technologies where brawn matches to the scale of the brain. We discuss our experiments with thin film ferroelectric motors 2mm in diameter and larger 8mm versions machined from bulk ceramic and sketch possible applications in the surgical field.MIT Artificial Intelligence Laborator

Report on swimbladder disorder in the honeycomb grouper, Epinephelus merra

Swimbladder or airbladder is a thin layered epithelial sac filled with air, lying above the alimentary canal of bony fishes that regulates buoyancy of the fish so that the specific gravity of the fish always matches the depth at which it is swimming. Swimbladder disorder (SBD) is a condition caused by sudden temperature changes impacted stomach resulting from improper feeding or due to bacterial or viral infections of the bladder characterised by inability of the fish to keep a normal upright position in water. Normally gold fishes suffer from SBD due to their globoid body shape. Fish with SBD may float on their side or their back, swim in circles or take head-down posture

Secure and Efficient Way of Handling Medical Records in Cloud

ABSTRACT: Personal health records (PHRs) are touted as a new convenience technology for consumers. It enables the patients to create a health information of their own in a centralized way, which alleviate the storage, access and sharing of health data in the cloud environment. By storing the health information in the cloud various security issues should arise such us authorization, key management and efficient user revocation, therefore, before outsourcing the PHR in the cloud, it is a promising method to encrypt the PHR using Attribute Based Encryption. Existing cryptographic schemes are planned for single owner settings, here, dealt with multiple owner scenarios which reduce the key management complexity for owners and users. Enhancing the MA-ABE scheme to handle efficient and ondemand user revocation, and prove its security. The experimental results will show the security and efficiency of the proposed system