Technical note The effect of rate of decay of rain path profile on microwave communication

The attenuation of radio waves due to rain can be predicted with a good degree of accuracy, provided the rain rate characteristics over the entire path of propagation are known. The attenuation due to rain is usually deduced on the basis of point rain rate, which can lead to inaccuracy in the estimation of attenuation. We use the concept of rate of decay of rain path profile to estimate the attenuation due to rain. The attenuation has been deduced at 11GHz and 13.4 GHz for 56 elevation angle by using the theory of decay rate of rain path profile, its controlling factor, gamma, and rain rate distribution over Delhi, a tropical station in India. The theoretically-estimated attenuation is compared with observed values, as well as with values obtained using the International Radio Consultative Committee (CCIR) method. The CCIR model is found to overestimate the attenuation.     

Development of an Online Heat Index Measurement System for Thermal Comfort Determination

This paper presents the development of a reliable heat index (HI) measurement system for evaluating the thermal comfort of a particular building or a particular area. The HI is an index that combines air temperature and relative humidity (RH) to determine the human-perceived equivalent temperature. To measure the air temperature and RH, temperature to digital converter and RH to voltage converter is used. HI is calculated online with the help of embedded firmware of the microcontroller. This calculated value is then transferred to the computer through standard RS 232 serial port. The same sensor node is tested with the RS 485 network standard by changing the transceiver of the node. The system is calibrated using four standard saturated binary salt solutions.     

Evolution of microstructure and texture in an ultrafine-grained Al6082 alloy during severe plastic deformation

The evolution of microstructure and texture in Al6082 precipitation-hardened alloy during equal-channel angular pressing (ECAP) was studied. It was found that although the dislocation density and the subgrain size saturated after 1 pass, the size of grains bounded by high angle boundaries reached its minimum value only after 4 passes. Furthermore, the grain orientation distribution changes between 4 and 8 passes, indicating the development of grain boundary structure even after the saturation of the parameters of the microstructure. As a result of this evolution, the initial texture of the commercial alloy was diminished after 8 passes and the grain orientation distribution became to be close to random case.     

In situ nanocrystalline Fe–Si coating by mechanical alloying

A new approach for deposition of in situ nanocrystalline Fe–Si alloy coating on mild steel substrate by mechanical milling has been proposed. The thickness of nanocrystalline coating was a function of milling time and speed. Milling speed of 200 rpm was the optimum condition for development of uniform, hard, adherent and dense 200–300 μm thick nanocrystalline coating. A possible mechanism, consisting of three steps like repeated impact, cold welding and delamination, has been proposed for the formation of coating. These coatings have resulted in the increase of the hardness to almost double the value before coating.     

Studies on Hg(II) ion retention properties of cross-linked graft copolymer of acrylic acid and its analytical application

The effects of different parameters such as time, concentration, pH and temperature, on metal ion retention properties of the polymer have been investigated. Metal ion adsorption kinetics, isotherms and thermodynamics have been studied. A plausible mechanism for mercury ion retention has been suggested. Mercuric ion has been isolated quantitatively from various synthetic mixture containing metal ions (Ni²⁺, Cd²⁺, Pb²⁺ and Zn²⁺).     

Effect of heating mode on sintering of tungsten

Microwave heating is recognized for its various advantages, such as time and energy saving, very rapid heating rates, considerably reduced processing cycle time and temperature, fine microstructures and improved properties. The present paper investigates the feasibility of consolidating tungsten powders through microwave sintering. A comparative analysis has also been attempted between the sintering response of pure tungsten powder compact in a microwave and conventional furnace.     

Gradient histogram: Thresholding in a region of interest for edge detection

Selecting a threshold from the gradient histogram, a histogram of gradient magnitudes, of an image plays a crucial role in a gradient based edge detection system. This paper presents a methodology to determine the threshold from a gradient histogram generated using any kind of linear gradient operator on an image. We consider the image as a random process with dependent samples, model the gradient histogram using theories of random process and random input to a system, and determine a region of interest in the gradient histogram using certain properties of a probability density function. Standard histogram thresholding techniques are then used within the region of interest to get the threshold value. To obtain the edges, this threshold value is then used as the upper threshold of the hysteresis thresholding technique that follows the non-maximum suppression operation applied on the gradient magnitude image. The proposed methodology of determining a threshold in a gradient histogram is deduced through rigorous analysis and hence it helps in achieving consistently appreciable edge detection performance. Experimental results using different real-life and benchmark images are shown to demonstrate the effectiveness of the proposed technique.     

Comparative Study on the Properties of Galvanically Deposited Nano- and Microcrystalline Thin Films of PbSe

Thin films of PbSe having both nano- and microstructures have been deposited on transparent conducting oxide (TCO)-coated glass substrates electrochemically, from an aqueous solution of Pb(OAc)₂, ethylenediamine tetraacetic acid (EDTA), and SeO₂. A Pb strip acted as the sacrificial anode, while the TCO glass was the cathode. No external bias was applied. The formation of PbSe was pH sensitive, and pH ~3 was found to be optimum for film deposition. Films grown at room temperature (25°C) were nanocrystalline (~25 nm), while those deposited at 80°C were microcrystalline (~150 nm). Films were characterized by x-ray diffraction studies, field-emission scanning electron microscope image analysis, infrared spectral analysis, and by both alternating-current (a.c.) and direct-current (d.c.) electrical measurements. A blue-shift was observed for the nanocrystalline films. Film resistivity and junction properties were obtained from electrical measurements.     

Router design for nano‐communication using actin quantum cellular automata

Logic expressions can be designed from actin filaments. It is a protein that makes the cellular structure and plays an important role in intracellular communication. Nano communication technique has been established using actin cellular automata. Among several rules, (1, 30) and (4, 27) rules have been used to design 2 to 1 multiplexer, 4 to 1 multiplexer, 1 to 2 demultiplexer and 1 to 4 demultiplexer. Router or data selector has been made of using multiplexer and demultiplexer. Three novel circuits such as multiplexer, demultiplexer and nano‐router have been designed using the projected mechanism. The primary focus of this proposed technique is on different designs of the multiplexer, demultiplexer and minimum cell count with minimum time steps. The different router circuits have been simulated with the help of Simulink by which output has been verified for different circuits. Stuck at fault analysis is also done in this study. Device density and power consumption have also been included in this study. A comparative analysis of the different designs of the router provides a better concept of circuit optimisation. Furthermore, this study analyses convenient forthcoming applications in nano‐technology and nano‐bio‐molecular systems involving the proposed parameters.Inspec keywords: cellular automata, demultiplexing equipment, proteins, logic circuits, logic design, telecommunication network routing, nanocommunication (telecommunication), nanoelectronics, multiplexing equipmentOther keywords: nanocommunication technique, actin cellular automata, 2 to 1 multiplexer design, data selector, multiplexer demultiplexer, actin‐based cellular automata, logic circuits, multiplexer cell count, demultiplexer cell count, minimum cell count, minimum time steps, router circuits, circuit optimisation, nanotechnology, nanobiomolecular systems, actin quantum cellular automata, logic expressions, actin filaments, cellular structure, intracellular communication, logic implementation, 4 to 1 multiplexer, 1 to 2 demultiplexer, 1 to 4 demultiplexer, nanorouter design, Simulink, stuck at fault analysis, device density, power consumption