The non-linear energy response of the plastic scintillator EJ-260 is measured with the MicroCHANDLER detector, using neutron beams of energy 5 to 27 MeV at the Triangle Universities Nuclear ...Laboratory. The first and second order Birks' constants are extracted from the data, and found to be kB=(8.70±0.93)×10−3g/cm2/MeV and kC=(1.42±1.00)×10−5(g/cm2/MeV)2. This result covers a unique energy range that is of direct relevance for fast neutron backgrounds in reactor inverse beta decay detectors. These measurements will improve the energy non-linearity modeling of plastic scintillator detectors. In particular, the updated energy response model will lead to an improvement of fast neutron modeling for detectors based on the CHANDLER reactor neutrino detector technology.
Sal (Shorea robusta Gaertn.) is one of the most important commercial tree species in Nepal and far-western Terai is renowned for its forest. This study was carried out in far-western Terai to develop ...volume models of Sal at tree level using destructive sampling. Out of 99 sample trees, 81 data were used to develop the models and 18 data for validation of the selected models. Over bark stem diameters were measured at an interval of 0.5 m in lowermost three sections, at an interval of 1 m for one section and at an interval of 2 m in upper part of the trunk from the ground level. Smalian’s formula was used to compute tree volume. Seven regression models were tested using DBH as a predictor variable. Cross validation of the independent data set was used to validate the selected models. The graphical analysis and fit statistics of the models were evaluated to select the best fit model. The selected model for total over bark stem volume is ln V = - 8.04674 + 2.26641 ln DBH with R2 of 92 % and standard error of 0.18. Similarly, the selected models for over bark volume up to 10 and 20 cm top diameter have R2 of 82.41% and 79.97% and standard errors of 0.35 and 0.42, respectively. The prediction error of the selected model was found to be less than 6%. Forest managers can use the recommended model in estimation of timber volume of Sal in a particular forest area of this region for effective forest management. Banko JanakariA Journal of Forestry Information for NepalVol. 27, No. 2, 2017, page: 3-11
In recent years, import of timber and other wood products from different parts of the world have been increasing in Nepal. The Government of Nepal aims to be a self-sustain in timber production. In ...this context, the objective of this study was to estimate efficiency of harvesting practices in Nepal in relation to stump-height. We collected the data on the stump-heights and other biometric characteristics of the trees from different felling sites of Kailali, Kanchanpur, Jhapa and Morang districts of Nepal. The volumes of the individual trees as well as the proportions of the volumes of their stumps with different heights were calculated. Correlation and ANOVA were used to find the significance of the associated factors. The average stump-heights using the conventional felling method and the chain saw method were found to be 0.74±0.17m and 0.46±0.21m, respectively with wider range. The correlation between the stump-height and diameter at breast height (dbh) was found significant. Similarly, the harvesting method, skill and experience of the tree-fellers and tree species were also found to be significant with the stump-heights. On an average, 5% of the total timber production equivalent to one million cubic feet (cft) is lost in the Fiscal Year 2074/075 in Nepal while adopting the conventional method of harvesting because of the higher stump-height than the one prescribed by the Government. The estimated loss was NRs. 2 billion (roughly equivalent to US $ 20 million, @NRS 100 = 1 USD) to the national economy, and the Government had to bear loss of about NRs. 500 million (roughly equivalent to 5 million USD) from the royalty of timber. This amount of loss could be reduced to half by using power chain saw. Lack of skilled laborers, poor implementation of law, and weak knowledge of officials were major causes for losses in harvesting practices. Moreover, about 2% wood volume loss can be avoided, without any further investment, by setting minimum standard stump-height at 15 cm and providing training to the field staff and tree harvesters.
We consider the potential for a 10 kg undoped cryogenic CsI detector operating at the Spallation Neutron Source to measure coherent elastic neutrino-nucleus scattering and its sensitivity to discover ...new physics beyond the standard model (BSM). Through a combination of increased event rate, lower threshold, and good timing resolution, such a detector would significantly improve on past measurements. We considered tests of several BSM scenarios such as neutrino nonstandard interactions and accelerator-produced dark matter. This detector’s performance was also studied for relevant questions in nuclear physics and neutrino astronomy, namely the weak charge distribution of Cs and I nuclei and detection of neutrinos from a core-collapse supernova. Published by the American Physical Society 2024
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Using an 185-kg NaITl array, COHERENT has measured the inclusive electron-neutrino charged-current cross section on ^{127}I with pion decay-at-rest neutrinos produced by the Spallation Neutron Source ...at Oak Ridge National Laboratory. Iodine is one the heaviest targets for which low-energy (≤50 MeV) inelastic neutrino-nucleus processes have been measured, and this is the first measurement of its inclusive cross section. After a five-year detector exposure, COHERENT reports a flux-averaged cross section for electron neutrinos of 9.2_{-1.8}^{+2.1}×10^{-40} cm^{2}. This corresponds to a value that is ∼41% lower than predicted using the MARLEY event generator with a measured Gamow-Teller strength distribution. In addition, the observed visible spectrum from charged-current scattering on ^{127}I has been measured between 10 and 55 MeV, and the exclusive zero-neutron and one-or-more-neutron emission cross sections are measured to be 5.2_{-3.1}^{+3.4}×10^{-40} and 2.2_{-0.5}^{+0.4}×10^{-40} cm^{2}, respectively.
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7.
Diameter-height models for the Terai tree species Khadka, A.; Subedi, T.; Ghimire, M. ...
Banko janakari : a journal of forestry information for Nepal = Banako jānakāri,
09/2015, Volume:
25, Issue:
1
Journal Article
Peer reviewed
Tree diameter-height relationship can be used as a key input component in forest growth and yield models, and description of stand dynamics. Various models of stem diameter and height relation were ...developed. Those were formulated and implemented during Terai forest inventory data calculations in the Forest Resource Assessment (FRA) Nepal Project. The field inventory was conducted from December, 2010 to March, 2011. The Concentric Circular Sample Plot was designed where the diameters at breast height of all the tallied trees and the heights of the sampled trees were measured. The data were handled with R-script in R Programme to generate non-linear mixed effects models in ‘lmfor’ package of forest biometrics functions of Mehtatalo. Different non-linear models were used to fit the diameter-height relation, which performed well in describing the relationships between the diameters and the heights of the Terai tree species depending on the sample size. The models were selected as the best fitted based on the statistical results such as standard error, Adjusted R2, RMSE and residuals. The best models for Shorea robusta and Terminalia alata were generated using Wykoff’s and Naslund’s functions, respectively.Banko Janakari, A Journal of Forestry Information for NepalVol. 25, No. 1Page: 50-54
The response of the United Nations General Assembly and Security Council to the terrorist attacks in the United States on September 11 - resolution 1373 of 28 September 2001 for the provision of a ...uniform set of measures for the control of terrorism globally - attempts by the General Assembly for the adoption of a comprehensive convention on international terrorism.
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We report the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) on germanium, measured at the Spallation Neutron Source at Oak Ridge National Laboratory. The Ge-Mini detector of ...the COHERENT collaboration employs large-mass, low-noise, high-purity germanium spectrometers, enabling excellent energy resolution, and an analysis threshold of 1.5 keV electron-equivalent ionization energy. We observe a on-beam excess of 20.6\(_{+7.1}^{-6.3}\) counts with a total exposure of 10.22 GWhkg and we reject the no-CEvNS hypothesis with 3.9 sigma significance. The result agrees with the predicted standard model of particle physics signal rate within 2 sigma.
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