The kinetics of gas transport in halide-activated aluminizing packs

The kinetics of diffusion of gaseous halides in an aluminizing pack are analyzed assuming the presence of an activator, as well as an aluminum-depleted zone. The influence of activator concentration on the aluminum transport rate is calculated for a wide range of activator concentrations in an AlF₃-activated pack. Theoretical results are compared with experimental data for the aluminization of nickel.     

Air quality monitoring in Chennai, India, in the summer of 2005

During the summer of 2005, concentrations of surface ozone (O(3)), oxides of nitrogen (NO(x)), respirrable suspended particulate matter (RSPM) and total suspended particulate matter (TSPM), relative humidity (RH), wind speed (WS) and wind direction (WD) were collected over successive periods of about 24 h at five sites. UV photometric ozone analyzer was used to measure the concentration of surface O(3). The study deals with the characteristics of hourly and daily mean surface O(3) under different climatic conditions, such as temperature, relative humidity, wind speed and wind direction and other pollutant concentrations. The maximum hourly O(3) concentration reached 53 ppb on 17th May. The ground-level O(3) concentration in Chennai varied between 2 and 53 ppb. The concentration of NO(x) and O(3) were below the prescribed limits. The TSPM values were exceeded the National Ambient Air Quality Standards (NAAQS) at Koyambedu, Mandaveli, Taramani and Vallalar Nagar study area.     

Predicting throughput in IEEE 802.11 based wireless networks using directional antenna

Wireless Networks - In IEEE 802.11 based wireless networks interference increases as more access points are added. A metric helping to quantize this interference seems to be of high interest. In...     

Nanoparticle transportation through a permeable duct with Joule heating influence

Microsystem Technologies - Nanofluid radiation in a semi permeable duct is analyzed in existence of Lorentz forces. Lorentz forces impact on energy equation are involved. Last ODEs were solved via...     

Voltage regulation of a stand-alone self-excited induction generator using STATCON with one cycle control technique for wind energy conversion system

ABSTRACT

This paper presents the simple voltage regulation scheme using a three-phase static VAr compensator (STATCON) for a stand-alone self-excited induction generator (SEIG) that uses variable-speed wind generation system. Most of the loads are inductive and need an equal amount of leading VArs, which is generated by the STATCON and injected at point of common coupling instantaneously. The one cycle control technique is considered and modified to implement for VAr compensation of SEIG voltage regulation. To emphasis the controller characteristics, a STATCON is designed for a 3-Ø, 0.75?kW, 415?V, 1.8?A Induction Machine and tested in simulation using MATLAB/SIMULINK software.     

Investigation on Phase Change Behavior of Paraffin Phase Change Material in a Spherical Capsule for Solar Thermal Storage Units

In this work, the melting and solidification behaviour of paraffin phase change material encapsulated in a stainless steel spherical container has been studied experimentally. A computational fluid dynamics analysis has also been performed for the encapsulated phase change material (PCM) during phase change process. In the melting process, the hot air, used as the heat transfer fluid enters the test section and flows over the spherical capsule resulting in the melting of phase change material. In the solidification process, the ambient air flows over the capsule and received heat from phase change material resulting in the solidification of phase change material. In the computational fluid dynamics, the constant wall boundary condition is employed for both melting (75°C) and solidification (36°C) processes since the internal conductive resistance offered by the PCM is much higher compared to the outer surface convective resistance. The time required for complete solidification and melting of the phase change material obtained from the computational fluid dynamics analysis are validated with the experimental results and a reasonable agreement is achieved. The reason for the deviation between the results are analyzed and reported.     

Group theory transformation for Soret and Dufour effects on free convective heat and mass transfer with thermophoresis and chemical reaction over a porous stretching surface in the presence of heat source/sink

The group theoretic method is applied for solving the problem of combined effect of thermal diffusion and diffusion thermo on free convective heat and mass transfer over a porous stretching surface in the presence of thermophoresis particle deposition with variable stream conditions. The application of one-parameter groups reduces the number of independent variables by one and consequently, the system of governing partial differential equations with the boundary conditions reduces to a system of ordinary differential equations with appropriate boundary conditions. The equations along with the boundary conditions are solved numerically by using Runge Kutta Gill integration scheme with shooting technique. Impact of Soret and Dufour effects in the presence of thermophoresis particle deposition with chemical reaction plays an important role on the flow field. The results thus obtained are presented graphically and discussed.