4,743 research outputs found

    Observable Dirac-type singularities in Berry's phase and the monopole

    Get PDF
    The physical reality and observability of 2n\pi Berry phases, as opposed to the usually considered modulo 2\pi topological phases is demonstrated with the help of computer simulation of a model adiabatic evolution whose parameters are varied along a closed loop in the parameter space. Using the analogy of Berry's phase with the Dirac monopole, it is concluded that an interferometer loop taken around a magnetic monopole of strength n/2 yields an observable 2n\pi phase shift, where n is an integer. An experiment to observe the effect is proposed.Comment: 12 pages Latex, 3 postscript figures; submitted to Physical Review Letters 15 September 2000; revised 19 November 200

    Assessment of Pesticide Use in Major Vegetables From Farmers\u27 Perception and Knowledge in Dhading District, Nepal

    Full text link
    A field study was carried out to assess the pesticide use status in major vegetable crops from farmers\u27 perception and knowledge in Dhading, Nepal in 2019. Field study was carried with 100 commercial farmer\u27s using semi-structure questionnaire by face to face interview. This study was analyzed by categorization of farmers into small holder (51) and large holder (49) groups on the basis of mean area of vegetable cultivation (6.48 ropani). The highest amount of pesticides is needed in tomato in both large holders and small holders according to the farmer\u27s experience. Among the study farmer\u27s, 41% of them spray the pesticides by making a cocktail or mixed method and 56%  follow the waiting period of 3-5 days in both of the cases. A significant positive correlation was found at 5% level of significance between the knowledge and practice pattern of waiting period of the pesticides and negative correlation was found between the Personal Protective equipment score and health hazard score. Headache was the major health hazards faced by the farmers which was higher in small holders (66.7%) as compared to the large holders (46.9%). Mask was the most used PPE by the farmer\u27s i.e. by 83% in overall. Fourty three percent of the farmer\u27s throw the pesticide containers in secret place after using of it.The use of PPE was seen lower in small holders as compared to the large holders. This study reveals the necessities of suitable program and policies regarding the knowledge, safe handling and use of pesticide among the farmer\u27s level

    On the origin of the artesian groundwater and escaping gas at Narveri after the 2001 Bhuj earthquake

    Get PDF
    At Narveri, north of Khavada in the Great Rann of Kachchh, an outflow of groundwater continued even more than four months after the Bhuj earthquake of 26 January 2001, although at a considerably reduced rate compared to that immediately following the earthquake. Air or gas bubbling through the freshly oozing water has also been observed. We had collected a large number of samples from different parts of Gujarat, where post-earthquake groundwater outpourings were reported. Narveri, however, was the only site where the samples showed dissolved helium concentrations, significantly above the air equilibration value. Based on measurements of helium, radon, chloride, sulphate and sodium concentrations and temperature, we suggest that the flowing water and escaping gases at Narveri have a deep confined source with a reservoir age in excess of ~ 104 years

    Evaluation of the performance of microprocessor-based colorimeter

    Get PDF
    Colorimetric estimations have an important role in quantitative studies. An inexpensive and portable microprocessor-based colorimeter developed by the authors is described in this paper. The colorimeter uses a light emitting diode as the light source; a pinphotodiode as the detector and an 8085A microprocessor. Blood urea, glucose, total protein, albumin and bilirubin from patient blood samples were analysed with the instrument and results obtained were compared with assays of the same blood using a Spectronic 21. A good correlation was found between the results from the two instruments

    Color Comfort Evaluation of Dye-Sensitized Solar Cell (DSSC) Based Building-Integrated Photovoltaic (BIPV) Glazing after 2 Years of Ambient Exposure

    Get PDF
    This is the final version. Available on open access from the American Chemical Society via the DOI in this recordData availability: in support of open access research, all underlying article materials (data, models) can be accessed upon request via email to the corresponding author.Transmitted external daylight through semitransparent type building integrated photovoltaic (BIPV) windows can alter the visible daylight spectrum and render different colors, which can have an impact on building's occupants' comfort. Color properties are defined by the color rendering index (CRI) and correlated color temperature (CCT). In this work, a less explored color comfort analysis of N719 dye-sensitized TiO2 based dye-sensitized solar cell (DSSCs) BIPV window was characterized and analyzed after 2 years of ambient exposure. Three different DSSCs were fabricated by varying TiO2 thickness. The reduced average visible transmission was observed while enhanced color properties were obtained for all three DSSCs. This study could pave way to future developments in the area of BIPV technology using DSSC in terms of their long-term exploration.Engineering and Physical Sciences Research Council (EPSRC

    Long-term evolution of the heliospheric magnetic field inferred from cosmogenic 44^{44}Ti activity in meteorites

    Get PDF
    Typical reconstructions of historic heliospheric magnetic field (HMF) BHMFB_{\rm HMF} are based on the analysis of the sunspot activity, geomagnetic data or on measurement of cosmogenic isotopes stored in terrestrial reservoirs like trees (14^{14}C) and ice cores (10^{10}Be). The various reconstructions of BHMFB_{\rm HMF} are however discordant both in strength and trend. Cosmogenic isotopes, which are produced by galactic cosmic rays (GCRs) impacting on meteoroids and whose production rate is modulated by the varying HMF convected outward by the solar wind, may offer an alternative tool for the investigation of the HMF in the past centuries. In this work, we aim to evaluate the long-term evolution of BHMFB_{\rm HMF} over a period covering the past twenty-two solar cycles by using measurements of the cosmogenic 44^{44}Ti activity (τ1/2=59.2±0.6\tau_{1/2} = 59.2 \pm 0.6 yr) measured in 20 meteorites which fell between 1766 and 2001. Within the given uncertainties, our result is compatible with a HMF increase from 4.870.30+0.244.87^{+0.24}_{-0.30} nT in 1766 to 6.830.11+0.136.83^{+0.13}_{-0.11} nT in 2001, thus implying an overall average increment of 1.960.35+0.431.96^{+0.43}_{-0.35} nT over 235 years since 1766 reflecting the modern Grand maximum. The BHMFB_{\rm HMF} trend thus obtained is then compared with the most recent reconstructions of the near-Earth heliospheric magnetic field strength based on geomagnetic, sunspot number and cosmogenic isotope data.Comment: Accepted for publication in Astronomy and Astrophysic
    corecore