Submunitions should exhibit optimum terminal performance at target end when released from certain pre-determined height. Selection of an optimum height of release of the submunitions depends on the terminal parameters...Submunitions should exhibit optimum terminal performance at target end when released from certain pre-determined height. Selection of an optimum height of release of the submunitions depends on the terminal parameters like forward throw, remaining velocity, impact angle and flight time. In this paper,the effects of initial firing conditions and height of release on terminal performance of submunitions discussed in detail. For different height of release, the relation between range and forward throw is also established & validated for a number of firing altitude and rocket configurations.展开更多
Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is larg...Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is largely governed by seasonal snow cover and snowmelt.Therefore,accurate estimation of seasonal snow cover dynamics and snowmeltinduced runoff is important for sustainable water resource management in the region.The present study looks into spatio-temporal variations of snow cover for past decade and stream flow simulation in the Jhelum River basin.Snow cover extent(SCE) was estimated using MODIS(Moderate Resolution Imaging Spectrometer) sensor imageries.Normalized Difference Snow Index(NDSI) algorithm was used to generate multi-temporal time series snow cover maps.The results indicate large variation in snow cover distribution pattern and decreasing trend in different sub-basins of the Jhelum River.The relationship between SCE-temperature,SCE-discharge and discharge-precipitation was analyzed for different seasons and shows strong correlation.For streamflow simulation of the entire Jhelum basin Snow melt Runoff Model(SRM) used.A good correlation was observed between simulated stream flow and in-situ discharge.The monthly discharge contribution from different sub-basins to the total discharge of the Jhelum River was estimated using a modified version of runoff model based on temperature-index approach developed for small watersheds.Stream power - an indicator of the erosive capability of streams was also calculated for different sub-basins.展开更多
The northwestern Himalaya harbors high levels of biodiversity due to its unique topography, climatic conditions and heterogeneity. Forest fragmentation is one of the major threats causing a decline in biodiversity in ...The northwestern Himalaya harbors high levels of biodiversity due to its unique topography, climatic conditions and heterogeneity. Forest fragmentation is one of the major threats causing a decline in biodiversity in the Himalayan region. We assesses forest fragmentation and changes in land use land cover（LULC） patterns using multi-temporal satellite data over a time span of four decades（1976–2013）. Fragmentation analysis using the Landscape Fragmentation Tool（LFT） reveals a decrease in core and edge areas by 14 and 2.3 %, respectively; while an increase in non-forest, patch area and perforation area by 2.1, 0.4, and 14 %, respectively. The LULC dynamics show that the areas under dense forest and scrub forest have decreased by 2.8 % and 1.9 %, respectively; and there is an increase in open forest, crop land and fallow land area by 2.6, 1.7 and 2.1 %, respectively. The quantification of landscape heterogeneity is undertaken with the help of landscape metrics computed using FRAGSTATS at class and landscape level, showing signs of increased fragmentation. Our study provides baseline database that can support the future biodiversity conservation and sustainable forest management initiatives.展开更多
Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate （te...Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate （temperature, precipitation, drought, wind etc.）. Available infor- mation is not sufficient to support a quantitative assessment of the eco- logical, social and economic consequences. The present study assessed shifts in forest cover types of Western Himalayan Eco-region （700-4 500 m）. 100 randomly selected samples （75 for training and 25 for testing the model）, genetic algorithm of rule set parameters and climatic envelopes were used to assess the distribution of five prominent forest cover types （Temperate evergreen, Tropical semi-evergreen, Temperate conifer, Sub- tropical conifer, and Tropical moist deciduous forests）. Modelling was conducted for four different scenarios, current scenario, changed precipi- tation （8% increase）, changed temperature （1.07℃ increase）, and both changed temperature and precipitation. On increasing precipitation a downward shift in the temperate evergreen and tropical semi-evergreen was observed, while sub-tropical conifer and tropical moist-deciduous forests showed a slight upward shift and temperate conifer showed ＇no shift. On increasing temperatm＇e, an upward shift in all forest types was observed except sub-tropical conifer forests without significant changes. When both temperature and precipitation were changed, the actual dis- tribution was maintained and slight upward shift was observed in all the forest types except sub-tropical conifer. It is important to understand the likely impacts of the projected climate change on the forest ecosystems, so that better management and conservation strategies can be adopted for the biodiversity and forest dependent community. Knowledge of impact mechanisms also enables identification and mitigation of some of the conditions that increase vulnerability to climate change in the forest sector.展开更多
Twenty heat tolerant wheat genotypes were evaluated in three heat stress environments of Bangladesh such as Wheat Research Center (WRC), Nashipur, Dinajpur, Regional Wheat Research Center, BARI, Gazipur, Regional Whea...Twenty heat tolerant wheat genotypes were evaluated in three heat stress environments of Bangladesh such as Wheat Research Center (WRC), Nashipur, Dinajpur, Regional Wheat Research Center, BARI, Gazipur, Regional Wheat Research Center, RARS, Jashore in 2015-2016. The experiments were conducted in RCBD with three replications in 2015-2016. The stability and response to change of location and sowing time of the genotypes were assessed through AMMI model and regression coefficient analysis on seven characters, <i>viz</i>. days to heading, days to maturity, plant height (cm), spikes m<sup>-2</sup>, grains spike<sup>-1</sup>, 1000-grain weight (g) and yield (kg·ha<sup>-1</sup>). Among the linear interac<span>tions, sowing time alone exerted the maximum sum of square (335,388,000.00**)</span> and among the non-linear interactions, location × year paid the highest effect (7,676,490.00**), which was followed by year × location × sowing time interaction (3,956,500.00**). The highest grain yield (4475.3 kg·ha<sup>-1</sup>) was obtained from the genotype G13, followed by the genotypes G17 (4460.8 kg·ha<sup>-1</sup>) and G19 (4404.7 kg·ha<sup>-1</sup>). The genotype G8 had the smallest interaction effect, while the genotype G14 followed by G10 responded vigorously to amelioration. The genotypes G13, G18 and G19 showed averagely high yield and showed stability over the environmental modifications. The other two genotypes G20 and G12 exhibited great reduction of yield potential under unfavorable environment. The environment 121 proceeded by J121 and G131 appeared as favorable environments. The genotypes G13 and G19 produced high yield (kg·ha<sup>-1</sup>) in the favorable environments. The genotypes G16 and G18 high IPCa1 scores, indicated sensitive to mega-environmental changes. The best genotype with respect to environment was genotype G13. Genotypes G17 and G19 were best for site E1;genotypes G14, G16 and G18 were best for site E2.展开更多
文摘Submunitions should exhibit optimum terminal performance at target end when released from certain pre-determined height. Selection of an optimum height of release of the submunitions depends on the terminal parameters like forward throw, remaining velocity, impact angle and flight time. In this paper,the effects of initial firing conditions and height of release on terminal performance of submunitions discussed in detail. For different height of release, the relation between range and forward throw is also established & validated for a number of firing altitude and rocket configurations.
文摘Snowmelt is an important component of any snow-fed river system.The Jhelum River is one such transnational mountain river flowing through India and Pakistan.The basin is minimally glacierized and its discharge is largely governed by seasonal snow cover and snowmelt.Therefore,accurate estimation of seasonal snow cover dynamics and snowmeltinduced runoff is important for sustainable water resource management in the region.The present study looks into spatio-temporal variations of snow cover for past decade and stream flow simulation in the Jhelum River basin.Snow cover extent(SCE) was estimated using MODIS(Moderate Resolution Imaging Spectrometer) sensor imageries.Normalized Difference Snow Index(NDSI) algorithm was used to generate multi-temporal time series snow cover maps.The results indicate large variation in snow cover distribution pattern and decreasing trend in different sub-basins of the Jhelum River.The relationship between SCE-temperature,SCE-discharge and discharge-precipitation was analyzed for different seasons and shows strong correlation.For streamflow simulation of the entire Jhelum basin Snow melt Runoff Model(SRM) used.A good correlation was observed between simulated stream flow and in-situ discharge.The monthly discharge contribution from different sub-basins to the total discharge of the Jhelum River was estimated using a modified version of runoff model based on temperature-index approach developed for small watersheds.Stream power - an indicator of the erosive capability of streams was also calculated for different sub-basins.
基金supported by the Ministry of Environment&Forests(MoEF)Government of India(GoI)(Project Serial Number:R&D/NNRMS/2/2013-14)
文摘The northwestern Himalaya harbors high levels of biodiversity due to its unique topography, climatic conditions and heterogeneity. Forest fragmentation is one of the major threats causing a decline in biodiversity in the Himalayan region. We assesses forest fragmentation and changes in land use land cover（LULC） patterns using multi-temporal satellite data over a time span of four decades（1976–2013）. Fragmentation analysis using the Landscape Fragmentation Tool（LFT） reveals a decrease in core and edge areas by 14 and 2.3 %, respectively; while an increase in non-forest, patch area and perforation area by 2.1, 0.4, and 14 %, respectively. The LULC dynamics show that the areas under dense forest and scrub forest have decreased by 2.8 % and 1.9 %, respectively; and there is an increase in open forest, crop land and fallow land area by 2.6, 1.7 and 2.1 %, respectively. The quantification of landscape heterogeneity is undertaken with the help of landscape metrics computed using FRAGSTATS at class and landscape level, showing signs of increased fragmentation. Our study provides baseline database that can support the future biodiversity conservation and sustainable forest management initiatives.
文摘Climate is a critical factor affecting forest ecosystems and their capacity to produce goods and services. Effects of climate change on forests depend on ecosystem-specific factors including dimensions of climate （temperature, precipitation, drought, wind etc.）. Available infor- mation is not sufficient to support a quantitative assessment of the eco- logical, social and economic consequences. The present study assessed shifts in forest cover types of Western Himalayan Eco-region （700-4 500 m）. 100 randomly selected samples （75 for training and 25 for testing the model）, genetic algorithm of rule set parameters and climatic envelopes were used to assess the distribution of five prominent forest cover types （Temperate evergreen, Tropical semi-evergreen, Temperate conifer, Sub- tropical conifer, and Tropical moist deciduous forests）. Modelling was conducted for four different scenarios, current scenario, changed precipi- tation （8% increase）, changed temperature （1.07℃ increase）, and both changed temperature and precipitation. On increasing precipitation a downward shift in the temperate evergreen and tropical semi-evergreen was observed, while sub-tropical conifer and tropical moist-deciduous forests showed a slight upward shift and temperate conifer showed ＇no shift. On increasing temperatm＇e, an upward shift in all forest types was observed except sub-tropical conifer forests without significant changes. When both temperature and precipitation were changed, the actual dis- tribution was maintained and slight upward shift was observed in all the forest types except sub-tropical conifer. It is important to understand the likely impacts of the projected climate change on the forest ecosystems, so that better management and conservation strategies can be adopted for the biodiversity and forest dependent community. Knowledge of impact mechanisms also enables identification and mitigation of some of the conditions that increase vulnerability to climate change in the forest sector.
文摘Twenty heat tolerant wheat genotypes were evaluated in three heat stress environments of Bangladesh such as Wheat Research Center (WRC), Nashipur, Dinajpur, Regional Wheat Research Center, BARI, Gazipur, Regional Wheat Research Center, RARS, Jashore in 2015-2016. The experiments were conducted in RCBD with three replications in 2015-2016. The stability and response to change of location and sowing time of the genotypes were assessed through AMMI model and regression coefficient analysis on seven characters, <i>viz</i>. days to heading, days to maturity, plant height (cm), spikes m<sup>-2</sup>, grains spike<sup>-1</sup>, 1000-grain weight (g) and yield (kg·ha<sup>-1</sup>). Among the linear interac<span>tions, sowing time alone exerted the maximum sum of square (335,388,000.00**)</span> and among the non-linear interactions, location × year paid the highest effect (7,676,490.00**), which was followed by year × location × sowing time interaction (3,956,500.00**). The highest grain yield (4475.3 kg·ha<sup>-1</sup>) was obtained from the genotype G13, followed by the genotypes G17 (4460.8 kg·ha<sup>-1</sup>) and G19 (4404.7 kg·ha<sup>-1</sup>). The genotype G8 had the smallest interaction effect, while the genotype G14 followed by G10 responded vigorously to amelioration. The genotypes G13, G18 and G19 showed averagely high yield and showed stability over the environmental modifications. The other two genotypes G20 and G12 exhibited great reduction of yield potential under unfavorable environment. The environment 121 proceeded by J121 and G131 appeared as favorable environments. The genotypes G13 and G19 produced high yield (kg·ha<sup>-1</sup>) in the favorable environments. The genotypes G16 and G18 high IPCa1 scores, indicated sensitive to mega-environmental changes. The best genotype with respect to environment was genotype G13. Genotypes G17 and G19 were best for site E1;genotypes G14, G16 and G18 were best for site E2.
