Explore the vast range of titles available.

Consumption of contaminated groundwater leads to serious health problems and may restrain the socio-economic development of society. The study aims to estimate the groundwater contamination and human health risks induced by fluoride and nitrate along the east coast of Tamil Nadu and Pondicherry, south India. Sixty-six samples were collected from the study site to test the level of groundwater contamination. The pH revealed acidic to alkaline water samples, and chemical analysis suggests excess F‾ and NO3‾ in few sites. The major water types in the area are Ca–Cl, Ca–HCO3, and mixed Ca–Mg–Cl. Rock–water interaction is the vital process influencing water chemistry. Hydrogeochemical processes such as reverse ion exchange, ion exchange, mineral dissolution, and silicate weathering control the concentration of ions. Human interventions are also accountable for the supply of toxic contaminants in the groundwater system. The fluoride and nitrate concentrations reported a maximum of 1.78 and 100.0 mg/L, respectively. Elevated fluoride values were reported from the southern, central, and northwestern parts, whereas nitrate concentration was noted towards the southwestern, central, and northeastern parts of the study area. The non-carcinogenic risks to different age groups such as children, females, and males were estimated by calculating hazard quotient (HQ) and total hazard index (THI). Based on THI, 59.09, 51.52, and 34.85% of the child, female and male populations respectively, are under health risk. The study concludes that child and female categories are more vulnerable to health risks in comparison with males. The study's findings may help to take adequate measurements to control the potential health risk in the future.

The study attempts to decipher saline water invasion and aided geochemical influences activated along the coastal zones of Tamil Nadu and Puducherry. Total 76 groundwater samples representing pre- and post-monsoon seasons were collected and examined for various parameters like Ca2+, K+, Na+, Mg2+, Cl−, HCO3−, NO3− and SO42−. Multiple techniques such as hydrochemical ionic changes, hydrochemical facies evolution model and seawater mixing index were incorporated to decipher the salinization process in the study area. Hydrochemical facies suggests 38.00% of groundwater samples representing CaHCO3 facies indicating fresh groundwater, mixed Ca–Cl groundwater by 26.00% of samples and about 36.00% samples suggest Na–Cl indicating saline water. Hydrochemical facies evolution diagram differentiated groundwater facies into freshening and intrusion phase irrespective of seasons. About 23.60% and 21.00% of samples during pre- and post-monsoon suggest samples influenced by seawater intrusion. Hydrochemical ionic changes of samples signify the positive fraction of seawater in both seasons, which shows the mixing of fresh groundwater with saline water. The seawater mixing index confirms a greater percentage of samples during post-monsoon (42.00%) have been influenced by seawater with values greater than one. Principle component analysis extracted three factors with a total variance of 67.31% and 62.03% during pre- and post-monsoon seasons, respectively. Factor 1 replicates the natural processes such as saline water intrusion and ion exchange, whereas factors 2 and 3 signify anthropogenic actions such as improper sewage disposal, use of fertilizers, domestic and industrial waste discharge influencing groundwater chemistry.

Coastal areas provide the largest avenue for human settlement worldwide. Among the different sources of water, groundwater comes under the most exploited for domestic, agriculture as well as industrial purposes. The present study is aimed to evaluate the hydrochemical characteristics and quality of groundwater. A total of 132 groundwater samples were collected during post-monsoon and pre-monsoon seasons and analyzed for major and minor ions, and the results were used to evaluate water quality parameters like sodium absorption ratio, magnesium absorption ratio, soluble sodium percentage, permeability index and residual sodium carbonate to establish water quality for various utilities. Groundwater samples show acidic to alkaline nature; dominant cations reported were in the order of Na+ > Ca2+ > K+ > Mg2+ and dominant anions Cl− > HCO3− > SO42−. The hardness of water ranges from soft to very hard. The major water types noted were CaHCO3, NaHCO3, CaCl2, mixed CaNaHCO3 and NaCl. Based on electrical conductivity, total dissolved solids and total hardness majority of the samples are appropriate for consumption and domestic utilities with few exceptions. Computed parameters reveal that a majority of the groundwater samples are suitable for agricultural purposes. The Gibbs plot reveals that interaction between rock and water is the major mechanism controlling groundwater chemistry in the study area. Multivariate statistical analyses such as correlation analysis and principal component analysis were carried out for better understanding and classification of water quality and factors which control the groundwater chemistry.

Nowadays detection of deterioration of electrical motors is an important topic of research. Vibration signals often carry diagnostic information of a motor. The authors proposed a setup for the analysis of vibration signals of three-phase induction motors. In this paper rotor fault diagnostic techniques of a three-phase induction motor (TPIM) were presented. The presented techniques used vibration signals and signal processing methods. The authors analyzed the recognition rate of vibration signal readings for 3 states of the TPIM: healthy TPIM, TPIM with 1 broken bar, and TPIM with 2 broken bars. In this paper the authors described a method of the feature extraction of vibration signals Method of Selection of Amplitudes of Frequencies – MSAF-12. Feature vectors were obtained using FFT, MSAF-12, and mean of vector sum. Three methods of classification were used: Nearest Neighbor (NN), Linear Discriminant Analysis (LDA), and Linear Support Vector Machine (LSVM). The obtained results of analyzed classifiers were in the range of 97.61 % – 100 %.

This study aims to provide general axioms that should hold for any theory of quantum gravity. These axioms imply that spacetime is an emergent structure, which emerges from information. This information cannot occur in spacetime, as spacetime emerges from it, and hence exists in an abstract mathematical Platonic realm. Thus, quantum gravity exists as a formal system in this Platonic realm. Gödel’s theorems apply to such formal systems, and hence they apply to quantum gravity. This limits the existence of a complete consistent theory of quantum gravity. However, we generalize the Lucas-Penrose argument and argue that a non-algorithmic understanding exists in this Platonic realm. It makes it possible to have a complete and consistent theory of quantum gravity.

Interindividual anatomical differences in the human cortex can lead to suboptimal current directions and may result in response variability of transcranial electrical stimulation methods. These differences in brain anatomy require individualized electrode stimulation montages to induce an optimal current density in the targeted area of each individual subject. We aimed to explore the possible modulatory effects of 140 Hz transcranial alternating current stimulation (tACS) on the somatosensory cortex using personalized multi-electrode stimulation montages. In two randomized experiments using either tactile finger or median nerve stimulation, we measured by evoked potentials the plasticity aftereffects and oscillatory power changes after 140 Hz tACS at 1.0 mA as compared to sham stimulation (n = 17, male = 9). We found a decrease in the power of oscillatory mu-rhythms during and immediately after tactile discrimination tasks, indicating an engagement of the somatosensory system during stimulus encoding. On a group level both the oscillatory power and the evoked potential amplitudes were not modulated by tACS neither after tactile finger stimulation nor after median nerve stimulation as compared to sham stimulation. On an individual level we could however demonstrate that lower angular difference (i.e., differences between the injected current vector in the target region and the source orientation vector) is associated with significantly higher changes in both P20/N20 and N30/P30 source activities. Our findings suggest that the higher the directionality of the injected current correlates to the dipole orientation the greater the tACS-induced aftereffects are.

A printed compact monopole antenna based on a single negative (SNG) metamaterial is proposed for ultra-wideband (UWB) applications. A low-profile, key-shaped structure forms the radiating monopole and is loaded with metamaterial unit cells with negative permittivity and more than 1.5 GHz bandwidth of near-zero refractive index (NZRI) property. The antenna offers a wide bandwidth from 3.08 to 14.1 GHz and an average gain of 4.54 dBi, with a peak gain of 6.12 dBi; this is in contrast to the poor performance when metamaterial is not used. Moreover, the maximum obtained radiation efficiency is 97%. A reasonable agreement between simulation and experiments is realized, demonstrating that the proposed antenna can operate over a wide bandwidth with symmetric split-ring resonator (SSRR) metamaterial structures and compact size of 14.5 × 22 mm2 (0.148 λ0 × 0.226 λ0) with respect to the lowest operating frequency.

In this article, a neural network-based segmentation approach for CT lung images was proposed using the combination of Neural Networks and region growing which combines the regions of different pixels. The proposed approach expresses a method for segmenting the lung region from lung Computer Tomography (CT) images. This method is proposed to obtain an optimal segmented region. The first step begins by the process of finding the area which represents the lung region. In order to achieve this, the regions of all the pixel present in the entire image is grown. Second step is, the grown region values are given as input to the Echo state neural networks in order to obtain the segmented lung region. The proposed algorithm is trained and tested for 1,361 CT lung slices for the process of evaluating segmentation accuracy. An average of 98.50% is obtained as the segmentation accuracy for the input lung CT images.

The performance of assessment in medical image segmentation is highly correlated with the extraction of anatomic structures from them, and the major task is how to separate the regions of interests from the background and soft tissues successfully. This paper proposes a fuzzy logic based bitplane method to automatically segment the background of images and to locate the region of interest of medical images. This segmentation algorithm consists of three steps, namely identification, rule firing, and inference. In the first step, we begin by identifying the bitplanes that represent the lungs clearly. For this purpose, the intensity value of a pixel is separated into bitplanes. In the second step, the triple signum function assigns an optimum threshold based on the grayscale values for the anatomical structure present in the medical images. Fuzzy rules are formed based on the available bitplanes to form the membership table and are stored in a knowledge base. Finally, rules are fired to assign final segmentation values through the inference process. The proposed new metrics are used to measure the accuracy of the segmentation method. From the analysis, it is observed that the proposed metrics are more suitable for the estimation of segmentation accuracy. The results obtained from this work show that the proposed method performs segmentation effectively for the different classes of medical images.

In this work, we show that quantum state discrimination can be modified due to a change in the underlying topology of a system. In particular, we explicitly demonstrate that the quantum state discrimination of systems with underlying discrete topology differs from that of systems with underlying continuous topology. Such changes in the topology of a spacetime can occur in certain quantum gravity approaches. In fact, all approaches to quantum gravity can be classified into two types: those with underlying continuous topology (such as string theory) and those with an underlying discrete topology (such as loop quantum gravity). We demonstrate that the topology of these two types of quantum gravity approaches has different effects on the quantum state discrimination of low-energy quantum systems. We also show that any modification of quantum mechanics, which does not change the underlying topology, does not modify quantum state discrimination.