In-house contamination of potable water in urban slum of Kolkata, India: a possible transmission route of diarrhea

We have investigated and determined the potentiality of different water sources, both for drinking and domestic purposes, in diarrheal disease transmission in diarrhea endemic foci of urban slums in Kolkata, India in a one and half year prospective study. Out of 517 water samples, collected from different sources, stored water (washing) showed higher prevalence of fecal coliforms (58%) (p < 0.0001) in comparison with stored (drinking) samples (28%) and tap/tubewell water (8%) respectively. Among different sources, stored water (washing) samples had the highest non-permissible range of physico-chemical parameters. Fecal coliform levels in household water containers (washing) were comparatively high and almost 2/3 of these samples failed to reach the satisfactory level of residual chlorine. Interestingly, 7% stored water (washing) samples were found to be harboring Vibrio cholerae Improper usage of stored water and unsafe/poor sanitation practices such as hand washing etc. are highlighted as contributory factors for sustained diarrheal episodes. Vulnerability of stored water for domestic usage, a hitherto unexplored source, at domiciliary level in an urban slum where enteric infections are endemic, is reported for the first time. This attempt highlights the impact of quality of stored water at domiciliary level for fecal-oral contamination vis-à-vis disease transmission.     

Enhancement of room temperature ferromagnetism in Cd1−xNixSe nanoparticles

Cd_1?xNi_xSe (x = 0.0, 0.02, 0.05 and 0.1) nanoparticles have been synthesized by chemical route. X-ray diffraction analysis shows crystalline nature of synthesized nanoparticles possessing wurtzite phase having hexagonal structure. Transmission electron microscopy depicts spherical morphology and uniform particle size distribution of pure and Ni-doped CdSe nanoparticles. The blue-shift in band gap has been observed with Ni-doping concentration. Photoluminescence study shows the presence of intrinsic defects (V_Cd–V_Se) in the synthesized nanoparticles. Electron spin resonance (ESR) analysis reveals the long range ferromagnetic ordering in pure and doped nanoparticles. ESR study also indicates that Ni ions exist in +2 oxidation state in host nanoparticles. The magnetic hysteresis (M-H) loops display ferromagnetism at room temperature in pure and Ni-doped CdSe nanoparticles. The increase of ferromagnetic behavior has been observed with Ni-doping concentration. M-H analyses indicate that defects and carrier mediated exchange interactions are responsible for ferromagnetic ordering, in the present study.     

Fuel use and design analysis of improved woodburning cookstoves in the Guatemalan Highlands

This study examined the fuel use and design of an improved woodburning cookstove (plancha), in comparison to traditional cooking over an open woodfire. These cookstoves had been randomly introduced into population households in the Guatemalan Highlands that had previously used open woodfires. This research consisted of: (1) a 12-household Kitchen Performance Test (KPT) over a 4-day period and (2) single-day participant observation in five households. The KPT monitored fuel consumption and the number, age, and gender of people who were cooked for, while the participant observation was used to form a complete understanding of fuel use patterns and to examine the influence of stove condition and cooking behavior. In spite of fairly low variability in the fuel use data (coefficients of variation of about 0.34) the KPT did not show statistically significant differences in fuel use between the two cooking methods. It is possible that increased study power through a larger sample size may have resulted in a statistically significant difference in favor of the plancha, but it is doubtful that the size of the effect would be of any practical significance. Thus, although other studies have shown that the plancha is extremely effective in reducing indoor air pollution in the study area, the KPT did not indicate that it offered any benefits with respect to fuel use. Practical and experimental recommendations for future cookstove efficiency studies are presented, with directions for continued work in this area.     

Synchrophasor communication

Synchronized phasor measurements provide the basis for fine-grained wide area power quality monitoring in electric grids. Time-synchronized phasor measurement units (PMUs) are deployed at different locations in the grid and report 10–60 measurements/second to energy management systems or other applications. For control applications it is crucial to receive measurement data as soon as possible after a state change in order to trigger corrective actions in time to prevent incidents in the grid. In this paper we analyze characteristics of synchrophasor M2M communication for different network technologies, including VDSL, HSPA and LTE networks. We briefly review synchrophasor communication approaches and real-time demands. We then emulate PMU traffic and perform measurements on different networks. We show how the underlying technology influences one-way delay patterns for synchrophasor communication, which has direct implication on the achievable real-time properties.     

Statistical optimization of desugarization process parameters of liquid whole egg using response surface methodology

The glucose is considered to affect the quality of the dried egg products; therefore the statistical optimization of desugarization process parameters of Liquid whole egg (LWE) was carried out in this study. The fermentation of Liquid whole egg (LWE) was done using compressed baker’s yeast. A polynomial model was regressed between reducing sugar & desugarization conditions. The coefficient of determination (R²) of 0.998 (P < 0.0001) for the regressed model indicated about the adequacy of the model, which implies the model was significant to predict reducing sugar content at different fermentation conditions. Optimum conditions for complete desugarization of Liquid whole egg (LWE) were found to be time 6.49 h, temperature 28 °C, pH 6.40 and yeast concentration 3.8 g/L and confirmed by conducting actual experiments at these conditions.     

Structural and electrical properties of donor-doped NBT system synthesized by microwave-assisted solid-state reaction route

Journal of Materials Science: Materials in Electronics - A-site donor-doped NBT systems (Na0.5Bi0.5)1-xMxTi(1-x/4)O3 (M?=?La and Sm) were synthesized by microwave-assisted solid-state...     

Ferromagnetism in Fe-doped CdSe nanorods prepared by solvothermal route

The present work deals with the role played by structural defects and doping concentration on the observed ferromagnetic behavior in pure and Fe-doped CdSe nanorods. X-ray diffraction and Raman analyses reveal the formation of wurtzite phase hexagonal structure of the pure and Fe-doped CdSe nanorods, without any additional parasitic secondary phases. Selected area electron diffraction, transmission electron microscopy and high-resolution transmission electron microscopy results show the single crystalline nature of the synthesized nanorods, possessing diameter and length around 8–15 and 100–140 nm, respectively. Energy dispersive spectroscopy and UV–visible spectra indicate the incorporation of Fe in host nanorods. Electron spin resonance analysis shows that the Fe ions are present in +3 oxidation state in host CdSe nanorods. The magnetization versus applied field (M–H) curves has been measured with vibrating sample magnetometer at room temperature. The increase of saturation magnetization with Fe-doping concentration has been observed which can be explained by the bound magnetic polaron (F-center exchange mechanism) at defect sites in the host CdSe nanorods.     

Room temperature ferromagnetism in Tb-doped ZnO dilute magnetic semiconducting nanoparticles

Pure and Tb-doped ZnO nanoparticles have been synthesized by chemical co-precipitation method. The transmission electron microscopy study reveals the spherical morphology of synthesized nanoparticles with average particle size 14–18 nm. The effect of Tb-doping on structural, optical and magnetic properties has been studied. X-ray diffraction shows that pure and Tb-ZnO nanoparticles exhibit wurtzite structure having hexagonal phase with primitive unit cell. It further reveals that there is no effect of Tb-doping on the X-ray diffraction pattern up to 2 % doping, however, higher doping concentration result in accumulation of Tb on ZnO surface. Photoluminescence spectra reveal that the doping Tb in ZnO changes crystallographic structure generating non-radiative oxygen vacancies. Three emission peaks located around 423, 485 and 515 nm has been observed. Pure ZnO nanoparticles show diamagnetic character, however, Tb-doped ZnO nanoparticles exhibit room temperature ferromagnetism. The correlation between defects generated upon Tb-doping to the observed ferromagnetism, in the synthesized nanoparticles, has been reported.     

Fabrication Method,Ferromagnetic Resonance Spectroscopy and Spintronics Devices Based on the Organic-Based Ferrimagnet Vanadium Tetracyanoethylene

Organic-based magnetic materials have been used for spintronic device applications as electrodes of spin aligned carriers and spin-pumping substrates. Their advantages over more traditional inorganic magnets include reduced magnetic damping and lower fabrication costs. Vanadium tetracyanoethylene, V[TCNE]_x (x ≈ 2), is an organic-based ferrimagnet with an above room-temperature magnetic order temperature (T_c ≈ 400 K). V[TCNE]_x has deposition flexibility and can be grown on a variety of substrates via low-temperature chemical vapor deposition (CVD). A systematic study of V[TCNE]_x thin-film CVD parameters to achieve optimal film quality, reproducibility, and excellent magnetic properties is reported. This is assessed by broadband ferromagnetic resonance (FMR) that shows most narrow linewidth of ≈1.5 Gauss and an extremely low Gilbert damping coefficient. The neat V[TCNE]_x films are shown to be efficient spin injectors via spin pumping into an adjacent platinum layer. Also, under an optimized FMR linewidth, the V[TCNE]_x films exhibit Fano-type resonance with a continuum broadband absorption in the microwave range, which can be readily tuned by the microwave frequency.     

Understanding the Role of Grain Boundaries on Charge-Carrier and Ion Transport in Cs2AgBiBr6 Thin Films

Halide double perovskites have gained significant attention, owing to their composition of low-toxicity elements, stability in air, and recent demonstrations of long charge-carrier lifetimes that can exceed 1 µs. In particular, Cs₂AgBiBr₆ is the subject of many investigations in photovoltaic devices. However, the efficiencies of solar cells based on this double perovskite are still far from the theoretical efficiency limit of the material. Here, the role of grain size on the optoelectronic properties of Cs₂AgBiBr₆ thin films is investigated. It is shown through cathodoluminescence measurements that grain boundaries are the dominant nonradiative recombination sites. It also demonstrates through field-effect transistor and temperature-dependent transient current measurements that grain boundaries act as the main channels for ion transport. Interestingly, a positive correlation between carrier mobility and temperature is found, which resembles the hopping mechanism often seen in organic semiconductors. These findings explain the discrepancy between the long diffusion lengths >1 µm found in Cs₂AgBiBr₆ single crystals versus the limited performance achieved in their thin film counterparts. This work shows that mitigating the impact of grain boundaries will be critical for these double perovskite thin films to reach the performance achievable based on their intrinsic single-crystal properties.