Investigation of a Highly Loaded, High Pressure Ratio Axial Turbine Stage for Industrial Applications

The turbine component of a gas turbine engine is the most costly component due to its complexity, and life requirements, given the harsh environment in which it is required to operate. Minimizing the number of stages can lead to significant savings in terms of development efforts, materials, and serviceable parts. This philosophy has led to a significant increase in the work demanded from the typical stage. In this work, a highly loaded axial turbine stage was designed for high power-output industrial applications using a comprehensive set of investigations, which included parametric studies, throughflow solutions, and 2D airfoil shapes. The design procedure was defined and used for the conceptual design calculations; several parametric studies were conducted to assess the impact of various critical design parameters such as degree of reaction, rotor exit conditions, and annulus shape. A winning design was chosen based on several factors, and the Free Vortex solution was employed to define the design boundary conditions for the airfoils hubs and tips. The NASA Throughflow Code (TDII) was used to generate the throughflow solution for the stage, and 2D airfoil shape design and analysis was performed using an in-house code (T-Foil) for the design, and the commercial CFD code (Star-CD) for the mesh and flow solutions

MANAGING CONTENTION AVOIDANCE AND MAXIMIZING THROUGHPUT IN OBS NETWORK

Optical Burst Switching (OBS) is a promising technology for future optical networks. Due to its less complicated implementation using current optical and electrical components, OBS is seen as the first step towards the future Optical Packet Switching (OPS). In OBS, a key problem is to schedule bursts on wavelength channels whose bandwidth may become fragmented with the so-called void (or idle) intervals with both fast and bandwidth efficient algorithms so as to reduce burst loss. In this paper, a new scheme has been proposed to improve the throughput and to avoid the contention in the OBS network. The proposed scheme offers the same node complexity as that in general OBS networks with optical buffers. Also, it avoids burst blockings in transit nodes, turning it into an efficient and simple burst contention avoidance mechanism. Simulation results show that the proposed scheme has improvement of 15% in terms of burst loss probability as compared to OBS existing schemes and also maximizes the throughput of the network without deteriorating excessively other parameters such as end to end delay or ingress queues

A Channel Model Suitable for Employing Efficient Beam Steering on Tropospheric Communication Links

Tropospheric communication systems find extensive use in both civil and military applications for long distance point to point communication. 21st century warfare requires high performance tropo systems capable of supporting high data rates for real time communication between various fighting elements. Most of the research and development for enhancing performance of tropo systems, has been in minimizing propagation loss due to fast-fading of channel. Limited progress has been made to overcome slow, diurnal and seasonal, changes in troposphere, which lead to considerable signal attenuation. Beam steering can be used to minimize slow fading loss in tropospheric links, enhancing their performance. Transmitter and receiver antenna beams should be dynamically steered in order to point to the tropospheric heights that are most conducive for propagation at any given time, for receiving maximum power. This paper discusses prominent tropospheric channel models and examines their suitability for beam steering. Dinc’s ray-based model can be used for employing beam steering in tropospheric links. It employs a ray-based approach for determining powers received due to signal propagation at different tropospheric heights using real world data of atmospheric parameters obtained from NASA’s LIDAR experiment. However, Dinc’s model needs certain modifications for exact representation of tropospheric turbulence and its propagation characteristics. A modified ray-based channel model has been presented in this paper, derived by making required changes in Dinc’s model. Simulation results, showing a comparison of transmission loss obtained from modified model and Dinc’s model with widely used ITU-R P.2001 model, are presented in the paper for validation. The paper also presents calculation of received power for different heights using modified model, validating its suitability for beam steering. Real world atmospheric parameters have been obtained from Indian Meteorological Department (IMD) for validation process. Received powers obtained for different heights using modified model have been compared to determine the most favourable heights for signal propagation. Knowledge of favourable heights for different times of a day in different seasons, can be used to steer transmit and receive antenna beams towards the favourable heights, at any given time and day, resulting in efficient beam steering

Squamous cell carcinoma of tympanomastoid region – A rare and often misdiagnosed entity

Squamous cell carcinoma of the temporal bone and external auditory canal is a rare entity. We present a case of 62 year old male, with stage IV squamous cell carcinoma of tympanomastoid region. As the tumour was deemed unresectable, mass debulking was done and patient was given post-operative radiotherapy. The objective to report this case was to emphasise the importance of early diagnosis and prompt treatment for a better survival. A high index of suspicion is necessary as the initial presentation may mimic more common otologic conditions

High Speed Railway (HSR): India And The World

India has one of the largest rail networks in the world but has no line which can be classified as HSR allowing operational speed of 125mph. The current fastest train runs at 100 mph over a distance of only around 100 miles. However, supported by a robust political willingness, a new HSR corporation has been set up to kick-start the HSR projects from ideation to reality. Four major corridors have been identified and pre-feasibility studies have been commissioned. The first in this ambitious program is the HSR between Mumbai and Ahmedabad, two major population and commercial centers in the west of India. The success or failure of this project could show the way for future road map of HSR in India. This paper identifies and analyses the countries where HSR systems are in operation – their political, economic and social conditions relevant to HSR systems and then the features of HSR systems themselves to understand the commonalities between the nations that have opted for HSR. The objective is to identify if there is a common character or a baseline characteristic in terms of geographical, economic, political and social conditions which are essential to be a member of this exclusive club? Is there a standard financial and business model that has been adopted by these countries?Theattempt is also to compare these baseline benchmarks with those in India, to assess its strengths and weaknesses and reaffirm the chances of its success in taking up this project, one of the biggestever in its history. The results would be relevant not only for India but for all countries who aspire to be HSR countries in near future

Review Based Study On Risk Management Model For High Speed Indian Railway System

In this paper, a framework for risk management at railways has been studied and integrated into global safety management system of railways. Furthermore we studied how it was applied to a manually controlled full barrier road rail level crossing in Morocco. We studied different aspects that should be considered during the system definition phase where we suggested using functional diagrams for modeling operations at LC from the perspective of LC actors. It is a critical part for risk management and specifically for hazard identification where we provided different techniques that can be used; our experience shows that involvement of all stakeholders is a prerequisite to the success to this phase. Initiating events can be unveiled through brainstorming sessions and FTA can model complex interactions of events that have the potential to lead to accidents. Risk analysis can then be carried out provided that historical LC accident and incident data is available to estimate frequencies and consequences; ETA is the ideal tool for estimating consequences of hazards due to multiple causes. The existing risks are then classified and decisions are made regarding their tolerability, the ALARP principle can serve this purpose. A cost benefit analysis then helps prioritize risk treatment actions that should target intolerable risks. Control mechanisms should be also put in place to assess, monitor and review the risk control actions put in place. Finally, it is emphasized on the importance of having a database of historical accidents and incidents at LC for the success and efficiency for the suggested framework. Accidents at level crossings are the result of complex interactions between factors arising from the design and operations of level crossings. An important first step towards eliminating the causes of these accidents is thru understanding and assessing the risks associated with a given level crossing and acting on them. This paper presents review based study on risk management framework that serves this purpose

Antimicrobial activity of skin secretions isolated from Indian toad, Bufo melanostictus Schneider 1799

Amphibians like toads have been known to secrete antimicrobial secretions outside their body into their environments, through skin pores and parotid glands. Toad skin-secretions contain four types of compounds namely, biogenic amines, bufadienolides, alkaloids & steroids and peptides & proteins. Bulk of research relating to amphibian antimicrobial secretions has been done on frogs. In toads, such research has only been done in South America, Europe and China. Antimicrobial secretions vary considerably from specie-to-specie and drastically across various biomes. This prompted us to examine and confirm presence of antimicrobial activity (if any) in Indian Common Toad (Bufo melanostictus Schneider 1799) skin secretions since; no such analysis had been previously done on this toad which is found all across the South-east Asia. The antibacterial potency of toad skin secretions was tested against the bacteria, Escherichia coli. After running preliminary antibacterial analysis assays, we found that these cutaneous secretions retrieved from Indian Common Toad possessed potential bactericidal activity. The results that we got confirmed that some unexplored bactericidal components were present in skin secretions of these toads. These conclusions call for further research into biochemistry and molecular characterization of these components

Querying Capability Enhancement in Database Using Fuzzy Logic

We already know that Structured Query Language (SQL) is a very powerful tool. It handles data, which is crisp and precise in nature.but it is unable to satisfy the needs for data which is uncertain, imprecise, inapplicable and vague in nature. The goal of this work is to use Fuzzy techniques i.e linguistic expressions and degrees of truth whose result are presented in this paper. For this purpose we have developed the fuzzy generalized logical condition for the WHERE part of SQL. In this way, fuzzy queries are accessing relational databases in the same way as with SQL. These queries with linguistic hedges are converted into Crisp Query, by deploying an application layer over the Structured Query Languag