Informatics Publishing Limited

S. Sumalatha ¹, G. Sreenivasulu ²

Affiliations
1 Sathyabama University, Chennai, IN
2 Department of ECE, S.V. University, Tirupati, IN

Abstract

In this paper, techniques for increasing the capacity of a wireless system are described. The performance of different diversity schemes used to mitigate the fading effects is studied. It is also presented in this work, that apart from diversity combiners, the choice of modulation also has varying effects on fading mitigation. The effect of co-channel interference and channel fading on the data bits transmitted is considered. A practical requirement such as, that, systems must also have full-duplex provision, is taken care in this work. It is presented in this work, that the effects of flat fading may be reduced using diversity techniques.

Keywords

Fading, Co-Channel Interference (CCI), Adjacent Channel Interference (ACI), Outage Probability, Cell Splitting.

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G. Sreenivasulu ¹, K. Raghavendra Rao ¹

Affiliations
1 Department of Physics, Sri Krishnadevaraya University, Ananthapuramu - 515003, Andhra Pradesh, IN

Abstract

Objectives: In this paper we present the design and development of an embedded system for the measurement of Boltzmann’s constant using Texas Instruments’ microcontroller: MSP430G2553. Methods/ Statistical Analysis: A transistor connected in common-base configuration with collector and base maintained at the same voltage (known as diode connected transistor or Transdiode) is used as the Device Under Test (DUT). The base-emitter voltage (VBE) is varied by a stepper motorized potentiometer whose rotation is controlled by microcontroller. The collector current (IC) is measured by converting it into voltage (V) by I-to-V converter using operational amplifier. The temperature of the bath where DUT is placed is measured using LM35 temperature sensor. The base-emitter voltage VBE, collector current IC and temperature in Kelvin T are measured using MSP430G2553 microcontroller. The data is captured using terminal software PuTTY. These files are imported to the scientific graph plotting software Origin. The graphs are drawn between natural log values of IC versus VBE at ambient temperature. To perform the measurement at different temperatures a heater system with constant current source is designed and constructed in the laboratory. Findings: From the slope of ln(IC) versus VBE graph Boltzmann’s constant is calculated. The values of Boltzmann’s constant at different temperatures are averaged and compared with standard CODATA (2014) value and percentage of error is determined. Application/Improvement: Microcontroller based embedded system for the measurement of Boltzmann’s constant is rarely seen in literature. In the present work, a fully automatic electronic circuit for the estimation of Boltzmann’s constant is designed and developed. The system is built around Texas Instruments’ MSP430G2553 microcontroller and cost-effective, off-the-shelf components are used in the circuit construction.

Keywords

Boltzmann’s Constant, Diode Connected Transistor, Energia, Embedded System, MSP430G2553 Microcontroller, PuTTY, Transdiode.

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G. Sreenivasulu ¹, K. Raghavendra Rao ¹

Affiliations
1 Department of Physics, Sri Krishnadevaraya University, NH - 205, Anantapur - Tirupati Highway, Anantapuram - 515003, Andhra Pradesh, IN

Abstract

Objectives: Angular and linear velocity measurements play an important role in monitoring and controlling the speed of motors used in applications such as conveyors, turbines, robots, automobiles and other moving objects. In the present paper, an inexpensive and portable system for the measurement of rotations per minute (RPM), linear and angular velocities is developed using Texas Instruments Hall effect sensor: DRV5023-Q1 and microcontroller MSP430G2553. Methods/Statistical Analysis: A unipolar Hall sensor switch produces pulses when a tiny magnet is brought in its vicinity. These pulses are counted by using the microcontroller in a fixed time interval and number of pulses per second gives frequency or rotations per second (RPS). From frequency, RPM, angular and linear velocities are computed. Findings: The measured parameters are displayed on LCD. The experimental frequencies are compared with the frequencies measured using commercial frequency meter (PHILIPS PM6624D). The linearity in velocity measurement (RPM) is represented in the form of a graph. Application/Improvement: In the present work an inexpensive and robust system is designed and developed for the linear velocity measurement. Further, the system is portable and works on a single rechargeable 9V battery. Such systems can be used in complex environment also.

Keywords

Hall Effect Sensor, Linear Velocity, MSP430G2553, RPM, Tachometer.

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G. Sreenivasulu ¹, N. Jayaraju ¹, B. C. Sundara Raja Reddy ², T. Lakshmi Prasad ³, B. Lakshmanna ¹, K. Nagalakshmi ³

Affiliations
1 Department of Geology, Yogi Vemana University, Kadapa 516 003, IN
2 Department of Geology, Sri Venkateswara University, Tirupati 517 502, IN
3 Department of Earth Sciences, Yogi Vemana University, Kadapa 516 003, IN

Abstract

Coastal zones are dynamic interfaces of land and water of high ecological diversity and critical economic importance. The boundaries, shape and size of this coast change constantly under the influence of both natural and anthropogenic factors. The study area, Tupilipalem is one of the proposal sites for constructing a major port, to be named Dugarajapatnam Port, along the east coast of Andhra Pradesh, India. We have used multitemporal satellite images of IRS P6 LISS-III and Landsat 8 OLI/TIRS data from 2011 to 2015 to delineate changes in Tupilipalem coast. The subsequent short-term lagoon mouth closure and the long-term coastal erosion and accretion rates have been calculated for the periods between 2011 and 2015. Low river inflow, wind, tides, the movement of the waves and littoral currents play a key role in the closure of the lagoon mouth and also for the dynamic activities of erosion and accretion. Moreover, the impact on socio-economy and ecology of the study area during the lagoon mouth closure period has been studied.

Keywords

Coastal Zone, East Coast of India, Morphodynamics, Remote Sensing and GIS, Sediment Dynamics.

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