Community-Based Waste Management: Backwater Tourism as a Case Example

A healthy environment is essential for the growth of Tourism industry. The future of tourism is inevitably related to the environment. As important natural resources, backwaters should be preserved in a sustainable manner. SWM emerged as an essential for keeping tourist destination clean and livable. This paper analyses the community-based waste management process in one of the famous backwater tourist destinations of Kerala and explains the roles and activities of all stakeholders and their relationship at the community level

Simulation of ultrasound two-dimensional array transducers using a frequency domain model

Ultrasound imaging with two-dimensional ͑2D͒ arrays has garnered broad interest from scanner manufacturers and researchers for real time three-dimensional ͑3D͒ applications. Previously the authors described a frequency domain B-mode imaging model applicable for linear and phased array transducers. In this paper, the authors extend this model to incorporate 2D array transducers. Further approximations can be made based on the fact that the dimensions of the 2D array element are small. The model is compared with the widely used ultrasound simulation program FIELD II, which utilizes an approximate form of the time domain impulse response function. In a typical application, errors in simulated RF waveforms are less than 4% regardless of the steering angle for distances greater than 2 cm, yet computation times are on the order of 1/35 of those incurred using FIELD II. The 2D model takes into account the effects of frequency-dependent attenuation, backscattering, and dispersion. Modern beam-forming techniques such as apodization, dynamic aperture, dynamic receive focusing, and 3D beam steering can also be simulated

Absolute backscatter coefficient estimates of tissue-mimicking phantoms in the 5-50 MHz frequency range

Absolute backscatter coefficients in tissue-mimicking phantoms were experimentally determined in the 5-50 MHz frequency range using a broadband technique. A focused broadband transducer from a commercial research system, the VisualSonics Vevo 770, was used with two tissue-mimicking phantoms. The phantoms differed regarding the thin layers covering their surfaces to prevent desiccation and regarding glass bead concentrations and diameter distributions. Ultrasound scanning of these phantoms was performed through the thin layer. To avoid signal saturation, the power spectra obtained from the backscattered radio frequency signals were calibrated by using the signal from a liquid planar reflector, a water-brominated hydrocarbon interface with acoustic impedance close to that of water. Experimental values of absolute backscatter coefficients were compared with those predicted by the Faran scattering model over the frequency range 5-50 MHz. The mean percent difference and standard deviation was 54% 6 45% for the phantom with a mean glass bead diameter of 5.40 lm and was 47% 6 28% for the phantom with 5.16 lm mean diameter beads

Measurement of tendon strain during muscle twitch contractions using ultrasound elastography

Abstract-A 2-D strain estimation algorithm was used to estimate tendon strain from ultrasound data collected during muscle twitch contractions. We first used speckle tracking techniques to estimate frame-to-frame displacements of all pixels within a rectangular region of interest (ROI) positioned over a tendon. A weighted, least-squares approach was then solved for the displacements of the ROI endpoints that best fit the pixel displacements. We summed endpoint displacements across successive frames to determine the cumulative endpoint motion, which was then used to estimate the cumulative strain along the tendinous fibers. The algorithm was applied to ultrasound radiofrequency data, acquired at 74 frames per second over the tibialis anterior (TA) musculotendon junction (MTJ). The TA muscle was electrically stimulated with the subject holding voluntary preloads of 0%, 10%, 20%, 30%, 40%, and 50% of a maximum voluntary contraction (MVC). Peak tendon strains computed using elastography (0.06 to 0.80%) were slightly larger and occurred earlier (50-90 ms after stimulus) than calculations based on visual analysis of B-mode images. This difference likely reflected the more localized nature of the elastographic strain values. Estimates of the tangential elastic modulus (192 ± 58 MPa) were consistent with literature values obtained using more direct approaches. It is concluded that automated elastographic approaches for computing in vivo tendon strains could provide new insights into musculotendon dynamics and function

Radiofrequency electrode vibration-induced shear wave imaging for tissue modulus estimation: A simulation study

Quasi-static electrode displacement elastography, used for in-vivo imaging of radiofrequency ablation-induced lesions in abdominal organs such as the liver and kidney, is extended in this paper to dynamic vibrational perturbations of the ablation electrode. Propagation of the resulting shear waves into adjoining regions of tissue can be tracked and the shear wave velocity used to quantify the shear (and thereby Young’s) modulus of tissue. The algorithm used utilizes the time-to-peak displacement data (obtained from finite element analyses) to calculate the speed of shear wave propagation in the material. The simulation results presented illustrate the feasibility of estimating the Young’s modulus of tissue and is promising for characterizing the stiffness of radiofrequency-ablated thermal lesions and surrounding normal tissue