Non-linear weight adjustment in adaptive gamma correction for image contrast enhancement

Multimedia Tools and Applications - Image enhancement remains an intricate problem, crucial for image analysis. Several algorithms exist for the same. A few among these algorithms categorize images...     

Tensile behavior of a new single crystal nickel-based superalloy (CMSX-4) at room and elevated temperatures

Tensile behavior of a new single-crystal nickel-based superalloy with rhenium (CMSX-4) was studied at both room and elevated temperatures. The investigation also examined the influence of γ′ precipitates (size and distribution) on the tensile behavior of the material. Tensile specimens were prepared from single-crystal CMSX-4 in [001] orientation. The test specimens had the [001] growth direction parallel to the loading axis in tension. These specimens were given three different heat treatments to produce three different γ′ precipitate sizes and distributions. Tensile testing was carried out at both room and elevated temperatures. The results of the present investigation indicate that yield strength and ultimate tensile strength of this material initially increases with temperature, reaches a peak at around 800 °C, and then starts rapidly decreasing with rise in temperature. Both yield and tensile strength increased with increase in average γ′ precipitate size. Yield strength and temperature correlated very well by an Arrhenius type of relationship. Rate-controlling process for yielding at very high temperature (T ≥ 800 °C) was found to be the dislocation climb for all three differently heat-treated materials. Thermally activated hardening occurs below 800 °C whereas above 800 °C thermally activated softening occurs in this material.     

Experimental study and empirical evaluation of carrier compression and third order intermodulation products of unequal carriers in a communication satellite transponder

Carrier compression and third order intermodulation products of two and three unequal carriers have been studied experimentally using a 36 MHz wide C-band transponder of INSAT-1B satellite. From the experimental data, empirical relations for carrier compression for two unequal carriers have been derived, which agree with the measured data within ±0.5 dB. The empirical relations for carrier compression derived for two unequal carriers have been extended to three unequal carriers and good correlations with measured data have been obtained. Empirical relations for third order intermodulation products of two and three (f₁+f₂-f₃ type) unequal carriers have also been derived.     

Influence of non-stoichiometry of sulphides on adsorption isotherms of dyes

Depending on their non-stoichiometry, sulphides are classified as n-type or p-type semiconductors. Adsorption of dyes from aqueous and non-aqueous solutions has been made use of to study the surface characteristics of solid adsorbents. Their use in flotation as collectors or depressants is also reported. Adsorption of anionic tartrazine on CdS-doped Ag₂S shows a lower value compared to undoped Ag₂S. The dye adsorption characteristics on these sulphides has been explained on the basis of their defect-structures.     

Perception and practice regarding pulse polio immunisation in an urban community of Calcutta

A survey was conducted at an Integrated Child Development Services (ICDS) Scheme project in North Calcutta among 656 mothers having children less than 3 years of age to assess their perception and practice regarding pulse polio immunisation (PPI). It was revealed that 91.8% of under 3-year children received PPI on 9-12-1995 and 94.4% on 20-1-1996. Major reasons for not accepting the services on those two days included 'mothers unaware' (22%), 'child too small' (30.5%), etc. Major source of first information was television (TV)/radio (57.2%) followed by anganwadi workers (AWWs) (33.8%). However, majority of the mothers were finally motivated for PPI by AWWs (58.8%) followed by the role of TV/radio (34.1%). Although 70.7% mothers knew the name of the vaccine correctly, only 3.5% mothers could tell the exact purpose of its administration. Most mothers (73%) opined that 2 drops of oral polio vaccine (OPV) was administered to their children and only 14.6% hoped that such programmes will be conducted by the Government in future. The average waiting time of mothers at immunisation centres was found to be 7.2 minutes.     

ESR and lyoluminescence measurements on Tris (hydroxymethyl) aminomethane

Electron spin resonance (ESR) and lyoluminescence (LL) measurements on Tris (hydroxymethyl) aminomethane have been carried out at different gamma exposures. The ESR spectral studies indicate the formation of two free radical species. The radical species formed at low dose range is responsible for LL emission and the second radical species formed at high exposure range inhibits the LL process. Studies on the effect of radical scavengers and oxygen on LL output also show that free radicals produced are the principal causative agents for the lyoluminescence and that oxygen is one of the reactants.     

Form/formula: a visual programming paradigm for user-definable userinterfaces

We have designed and implemented a visual programming environment, Hyper-flow on the PenPoint operating system. We call it HF/PP for short. Its primary goal is to provide a framework for UDUI in educational applications. The design of HF/PP, which uses only a pen and a microphone for input, is part of a research project to develop a pen based computer system for teaching preschool through twelfth grade mathematics. The article discusses the UDUI capabilities of HF/PP, represented by the programming constructs; form and formula, or the form/formula paradigm. To explain the paradigm, and other HF/PP constructs, we present three examples: converting between Fahrenheit and Celsius, designing arithmetic worksheets, and querying student records     

Use of linear profile layers for the evaluation of the admittance matrix of an inhomogeneous slab

It is seen that the convergence of values of the elements of the admittance matrix for periodic heat conduction through an inhomogeneous slab with a number of layers (layered structure method) is much faster when the conductivity profile in the layer is taken as linear (with least-square fit), than when the layer is considered as homogeneous.     

Queueing analysis of a threshold based priority scheme for ATMnetworks

A threshold-based priority scheme in which a tuning parameter is used to provide adequate quality of service to real-time traffic while providing the best possible service to the non-real-time traffic is proposed. The priority scheme is a generalization of the static priority scheme and the one-limited scheme and is more flexible than both. For this scheme, the authors carry out a queueing analysis and obtain the joint distribution of the queue-lengths. They show by numerical examples how the parameter of this scheme can be tuned dynamically, so that the tuning function can be integrated with the call admission policy