Characterization of underwater acoustic communication channel

1323-1329The objective of this work is to study the multipath underwater channel characteristics by estimating the channel impulse response and its derived functions such as scattering functions, power delay profile and Doppler spread. This work performs the channel characterization from the data measured from south- west Bay of Bengal during July 2017 at a range of about 1 km and 3 km in a depth of approximately 20 m. To estimate the channel impulse response, Linear Frequency Modulated (LFM) pulse with the bandwidth of 4 kHz and the center frequency of 11 kHz is used as a probe signal. Experimental data analysis shows the variations between two channels of 1 km and 3 km ranges. Other characterization functions such as multipath intensity profile and Doppler power spectrum are estimated from the channel impulse response. The estimated channel parameters convey that the channels are quasi stationary and the Doppler frequency spreads are due to the movement of the transmitter and receiver positions

An Experimental Study on Solar Flat Plate Collector Using an Alternative Working Fluid

This paper describes the performance of a solar water heater with an alternative working fluid. A solar flat plate collector of fIxed orientation was fabricated and connected to a heat exchanger, which was kept inside the water storage drum. The developed collector was a low temperature device operating with the temperature range of ambient to 100°C. Acetone was selected as an alternative working fluid and allowed to re-eirculate in a closed loop. A shell and tube type heat exchanger (non-mixing) was designed and fabricated for the heat transfer between acetone and water. The solar intensity increased from 55 mw/cm2 at 8.30 am to 85 mw/cm2 at 1.30 pm and decreased to 64 mw/cm2 at 5.00 pm. The absorber plate temperature, which remained nearly constant for the first two hours, went up to 90°C in the next two hours. It was nearly constant from 11.00 am to 1.30 pm and then dropped down to 72°C in the afternoon. The hot fluid was found to loose heat to the surrounding water at more or less constant rate from 11.30 am to 5.00 pm. The highest temperature of acetone (70°C) was observed during 1.00 pm to 2.00 pm. The temperature of water increased from 30°C to a maximum of 62°C. Overall efficiency of the system was found to be 45% while considering the solar input to the heat gained by the water. Alternative working fluids such as acetone, methanol or ethanol may be considered for substituting water in the flat plate collector in view of the fact that the fluids have low boiling point coupled with high latent heat of evaporation

Estimation of morphological and molecular genetic diversity in blackgram [Vigna mungo (L.) Hepper] under YMV hotspot regime

A phenotypic and molecular diversity study was conducted using seven traits and 19 SSR markers in a collection of 26 black gram genotypes. Phenotypic characterization was based on seven yield and yield related variable. The  field experiment  was  laid  out  at  Panboli village (YMV hotspot)  of Tirunelveli District in Tamilnadu during summer 2017. Genetic divergence was estimated on the basis of D2 values and 26 genotypes under study were grouped into six clusters by Tocher’s method. Seed yield per plant followed by Plant height and number of pods per plant contributed to the genetic divergence. The genetic distance announced using DICE dissimilarity co-efficient indicated highest divergence of 1.0 between VBN 8 and AUBG 17 and between VBN 8 and AUBG 19. The dendogram constructed using the DICE dissimilarity co-efficient between genotypes showed four apparent clusters based on marker allele distribution. Divergence was noted between the dissimilarity matrices based on the molecular and phenotypic diversity based on agronomic data.&nbsp

Classification of underwater targets from autonomous underwater vehicle sampled bistatic acoustic scattered fields

One of the long term goals of autonomous underwater vehicle (AUV) minehunting is to have multiple inexpensive AUVs in a harbor autonomously classify hazards. Existing acoustic methods for target classification using AUV-based sensing, such as sidescan and synthetic aperture sonar, require an expensive payload on each outfitted vehicle and post-processing and/or image interpretation. A vehicle payload and machine learning classification methodology using bistatic angle dependence of target scattering amplitudes between a fixed acoustic source and target has been developed for onboard, fully autonomous classification with lower cost-per-vehicle. To achieve the high-quality, densely sampled three-dimensional (3D) bistatic scattering data required by this research, vehicle sampling behaviors and an acoustic payload for precision timed data acquisition with a 16 element nose array were demonstrated. 3D bistatic scattered field data were collected by an AUV around spherical and cylindrical targets insonified by a 7–9 kHz fixed source. The collected data were compared to simulated scattering models. Classification and confidence estimation were shown for the sphere versus cylinder case on the resulting real and simulated bistatic amplitude data. The final models were used for classification of simulated targets in real time in the LAMSS MOOS-IvP simulation package [M. Benjamin, H. Schmidt, P. Newman, and J. Leonard, J. Field Rob. 27, 834–875 (2010)]United States. Office of Naval Research (Grant N00014-14-1- 0214

Perception and buying behaviour of consumers towards FPOs food products in Tamil Nadu

The present study was carried out to map the perception of consumers and to identify the factors influencing the consumer buying behaviour towards the food products of FPOs in Tamil Nadu. The results concluded that majority of the respondents purchased jaggery and sugar, cold pressed oil, snacks and millets category from the retail shops of FPOs. The quality and nutrient content were major product traits influencing consumers for purchasing the FPO food products. Most of the consumers felt that the quality and price of the food products were high in FPOs retail stores compared with other retail stores. So, FPOs should target high income people with high purchasing power who appreciate quality. Local people were purchasing the FPOs food products anytime. FPOs can devise effective marketing strategies to attract new customers from local and non-local customers. Most of the people have no awareness about FPOs retail outlets. Therefore, FPOs should pay attention in promoting their products and increasing the retail outlets for attracting the consumers and increasing the sales

"Effect of Psychosocial Intervention on Women ""Self-Help Group"" "

Self Help Groups (SHGs) of women in India have been recognized as an effective strategy for the empowerment of women in rural as well as urban areas. The study is quasi-experimental in nature, as it attempts to examine the impact of psychosocial intervention on the women self¬-help group. The Self-Esteem Inventory and the Rathus Assertiveness Scale was given to the group and pre-intervention and the post-intervention scores were obtained. Intervention consisted of teaching skills for assertiveness and self-esteem. The data collected during the pre-test and post-test were analysed using paired't' test. There was a significant difference in the self-esteem and assertiveness of the self-help group women after the psychosocial training

Analysis of polariton dispersion in metal nanocomposite based novel superlattice system

The influence of metal nanoparticles in tuning the polaritonic gap in a novel piezoelectric superlattice is studied. Dielectric function of the metal nanoparticles is analyzed using Kawabata-Kubo effect and Drude’s theory. The effective dielectric function of the nanocomposite system is studied using Maxwell Garnett approximation. Nanocomposite based LiTaO3 novel superlattice is formed by arranging the nanocomposite systems in such a way that their orientations are in the opposite direction. Hence there are two additional modes of propagation. The top most modes reflect the metal behavior of the nanoparticles. It is found that these modes of propagation vary with the filling factor. These additional modes of propagations can be exploited in the field of communication. Keywords: Nanocomposite, Piezoelectric materials, Novel superlattice, LiTaO3, Polaritonic ga

SCREENING OF LOW DENSITY POLYETHYLENE DEGRADING BACTERIA FROM POLLUTED SOIL WITH PLASTICS

Polyethylene waste accumulating in the environment is posing an ever increasing ecological risk. Plastics that are biodegradable can be considered environment friendly they have an increasing range of potential application and are driven by the growing use of plastics in packaging. Three hundred and fifty five microbial isolates (bacteria: 324 isolates & fungal: 31 isolates) were isolated from 10 plastic waste accumulated places in and around Sivakasi city, Tamil Nadu, India. Primary and secondary screening has been done for the bacterial isolates depending on bacterial growth in low density polyethylene solid and liquid medium. Eight isolates exhibited high efficient on LDPE degradation. These seven isolates have been identified as Pseudomonas sp., Bacillus sp., Staphylococcus sp., Serratia sp., Aspergillus japonicus, Aspergillus fumigatus, Penicilliun funiclosum and Fusarium moniliforms. Out of eight isolates Aspergillus japonicus (60.15%) and Bacillus sp (58.96%) revealed significant activity. Therefore, the present study states that, microbes has enough potential to degrade plastic with due course of time

Analysis of acoustic back scattered signals of two different underwater materials using Empirical Mode Decomposition and support vector machine

656-664<span style="font-size:10.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">In this work an attempt has been made to analyse and discriminate acoustic backscattered signals from underwater objects of two different materials of PVC and Brass. A laboratory study of underwater acoustic scattering of spherical objects of PVC and Brass material is carried out using Empirical Mode Decomposition (EMD), HilbertTransform (HT) and Support Vector Machine (SVM). Incident signal used for the measurement is a Linear Frequency Modulated (LFM) signal of finite duration with the signal bandwidth of 40 kHz to 80 kHz. More than 80 back scattered acoustic signals from the objects are recorded and processed for discrimination. An EMD method is designed to decompose the scattered signal and HT was used to extract the features for discrimination. EMD decomposes the backscattered signal into intrinsic mode functions ((IMFs) and the significant features are extracted from the HT. The classification or discrimination is investigated using support vector machine (SVM) with four types of kernels such as linear, quadratic, RBF and polynomial.  Performance of the SVM shows that the proposed method using EMD and Hilbert transform is useful for underwater object discrimination.</span