Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfal... more Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfall and high temperatures to simulate hot-arid environment for establishment of plants like Eucalyptus camaldulensis and Acacia arabica in plastic bags [with an objective to ...
Abstract Management strategies were developed to schedule irrigations with fixed-rotation level b... more Abstract Management strategies were developed to schedule irrigations with fixed-rotation level basin irrigation systems. A model that simulated the irrigation schedules of 8 crops and a number of planting dates was developed to predict seasonal Et, irrigation requirements, ...
An advanced application of BEM to the problem of wave screening by barriers is described. The BEM... more An advanced application of BEM to the problem of wave screening by barriers is described. The BEM formulation has been developed by utilizing advanced surface modelling, automatic (self-adaptive) error control in the numerical integration. The soil is modelled as a layered, isotropic and linear elastic or viscoelastic medium. The results of the analysis have been compared with full scale test data.
This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31... more This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31.25 on total length basis and the losses on 100 meter length basis were 3.62, 3.15 and 4.47 percent, respectively. The conveyance efficiency worked out to be 72.89, 74.15 and 68.75 ...
Abstract The country's geographical area covers around 88.2 mha including the northern a... more Abstract The country's geographical area covers around 88.2 mha including the northern areas. Ecologically, the country has diversified physiography and climate. To analyze the diversified status of the resources, a large dataset is required to interpret and analyze. GIS ...
Abstract Expansion rate and repeatability of four selected agricultural polymers (aquastock, P4C,... more Abstract Expansion rate and repeatability of four selected agricultural polymers (aquastock, P4C, aquasorb and P4F) were determined in free water under wet-dry-wet cycles at room temperature and atmospheric pressure. The aquastock and P4C were of coarse texture ...
A new method for the free-vibration analysis using the boundary element technique is presented. T... more A new method for the free-vibration analysis using the boundary element technique is presented. The method utilizes a fictitious vector function to approximate the inertia forces and then uses the well-known concept of complementary functions and particular integrals to ...
ABSTRACT Ground disturbance due to waves generated by a machine foundation can be detrimental to ... more ABSTRACT Ground disturbance due to waves generated by a machine foundation can be detrimental to adjacent structures or sensitive equipment operating nearby. Most of the vibratory energy that affects structures nearby is carried by surface (Rayleigh) waves that propagate in a zone close to the ground surface. Therefore, for machine foundations vibrating from moderate to high frequencies, the amplitude of ground motion can be reduced significantly by installing a wave barrier around the source. A three-dimensional boundary element algorithm incorporating quadratic elements has been used to perform an extensive parametric study on the effectiveness of open trenches as wave barriers. The key geometrical and material parameters that govern the performance of an open trench wave barrier have been identified, and a design formula in the form of an algebraic expression has been developed for estimating the vibration screening effectiveness of such barriers. Furthermore, through comparisons with published field test data and rigorous boundary element solutions, the validity of the design formula has been established.
Ahmad et al.: Benefits, supplemental, wheat, rainfed Tabie 2: Amount of supplemental irrigation a... more Ahmad et al.: Benefits, supplemental, wheat, rainfed Tabie 2: Amount of supplemental irrigation applied to wheat crop at NARC, Islamabad and Fatehianq. Locations Growing Seasons Growing Season Lencjth (days) Amount of Irrigation (mm) Seasonal I, 1, Ц Rainfall (mm) NARC ...
They are unknown but they cover an area of more than one million hectares, which is close to 10% ... more They are unknown but they cover an area of more than one million hectares, which is close to 10% of all irrigated land in Pakistan: spate irrigation systems, also called 'rod kohi', 'sailaba' or 'nai' in different parts of the country. Dependent on making the most out of short duration floods, they embody a unique and ancient culture of water sharing. This book describes for the very first time these special systems and the societies they have given rise to.
Abstract A model that simulated the irrigation schedules of a farm at watercourse command was dev... more Abstract A model that simulated the irrigation schedules of a farm at watercourse command was developed to predict net farm return, benefit-cost ratio, water use, percent water utilized, deep percolation, rainfall contribution and net return per unit of water applied including ...
Pakistan Journal of Biological Sciences, 2(4): 1415-1418,1999 Research Article, Low-cost Sand Fil... more Pakistan Journal of Biological Sciences, 2(4): 1415-1418,1999 Research Article, Low-cost Sand Filter For Domestic and Stockwater Use Jehan Zeb, M.Aslam, Shahid Ahmad and Aamir Kabir Water Resources Research Institute (WRRI), National Agricultural Research Center ...
Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfal... more Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfall and high temperatures to simulate hot-arid environment for establishment of plants like Eucalyptus camaldulensis and Acacia arabica in plastic bags [with an objective to ...
This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31... more This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31.25 on total length basis and the losses on 100 meter length basis were 3.62, 3.15 and 4.47 percent, respectively. The conveyance efficiency worked out to be 72.89, 74.15 and 68.75 ...
Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfal... more Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfall and high temperatures to simulate hot-arid environment for establishment of plants like Eucalyptus camaldulensis and Acacia arabica in plastic bags [with an objective to ...
Abstract Management strategies were developed to schedule irrigations with fixed-rotation level b... more Abstract Management strategies were developed to schedule irrigations with fixed-rotation level basin irrigation systems. A model that simulated the irrigation schedules of 8 crops and a number of planting dates was developed to predict seasonal Et, irrigation requirements, ...
An advanced application of BEM to the problem of wave screening by barriers is described. The BEM... more An advanced application of BEM to the problem of wave screening by barriers is described. The BEM formulation has been developed by utilizing advanced surface modelling, automatic (self-adaptive) error control in the numerical integration. The soil is modelled as a layered, isotropic and linear elastic or viscoelastic medium. The results of the analysis have been compared with full scale test data.
This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31... more This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31.25 on total length basis and the losses on 100 meter length basis were 3.62, 3.15 and 4.47 percent, respectively. The conveyance efficiency worked out to be 72.89, 74.15 and 68.75 ...
Abstract The country's geographical area covers around 88.2 mha including the northern a... more Abstract The country's geographical area covers around 88.2 mha including the northern areas. Ecologically, the country has diversified physiography and climate. To analyze the diversified status of the resources, a large dataset is required to interpret and analyze. GIS ...
Abstract Expansion rate and repeatability of four selected agricultural polymers (aquastock, P4C,... more Abstract Expansion rate and repeatability of four selected agricultural polymers (aquastock, P4C, aquasorb and P4F) were determined in free water under wet-dry-wet cycles at room temperature and atmospheric pressure. The aquastock and P4C were of coarse texture ...
A new method for the free-vibration analysis using the boundary element technique is presented. T... more A new method for the free-vibration analysis using the boundary element technique is presented. The method utilizes a fictitious vector function to approximate the inertia forces and then uses the well-known concept of complementary functions and particular integrals to ...
ABSTRACT Ground disturbance due to waves generated by a machine foundation can be detrimental to ... more ABSTRACT Ground disturbance due to waves generated by a machine foundation can be detrimental to adjacent structures or sensitive equipment operating nearby. Most of the vibratory energy that affects structures nearby is carried by surface (Rayleigh) waves that propagate in a zone close to the ground surface. Therefore, for machine foundations vibrating from moderate to high frequencies, the amplitude of ground motion can be reduced significantly by installing a wave barrier around the source. A three-dimensional boundary element algorithm incorporating quadratic elements has been used to perform an extensive parametric study on the effectiveness of open trenches as wave barriers. The key geometrical and material parameters that govern the performance of an open trench wave barrier have been identified, and a design formula in the form of an algebraic expression has been developed for estimating the vibration screening effectiveness of such barriers. Furthermore, through comparisons with published field test data and rigorous boundary element solutions, the validity of the design formula has been established.
Ahmad et al.: Benefits, supplemental, wheat, rainfed Tabie 2: Amount of supplemental irrigation a... more Ahmad et al.: Benefits, supplemental, wheat, rainfed Tabie 2: Amount of supplemental irrigation applied to wheat crop at NARC, Islamabad and Fatehianq. Locations Growing Seasons Growing Season Lencjth (days) Amount of Irrigation (mm) Seasonal I, 1, Ц Rainfall (mm) NARC ...
They are unknown but they cover an area of more than one million hectares, which is close to 10% ... more They are unknown but they cover an area of more than one million hectares, which is close to 10% of all irrigated land in Pakistan: spate irrigation systems, also called 'rod kohi', 'sailaba' or 'nai' in different parts of the country. Dependent on making the most out of short duration floods, they embody a unique and ancient culture of water sharing. This book describes for the very first time these special systems and the societies they have given rise to.
Abstract A model that simulated the irrigation schedules of a farm at watercourse command was dev... more Abstract A model that simulated the irrigation schedules of a farm at watercourse command was developed to predict net farm return, benefit-cost ratio, water use, percent water utilized, deep percolation, rainfall contribution and net return per unit of water applied including ...
Pakistan Journal of Biological Sciences, 2(4): 1415-1418,1999 Research Article, Low-cost Sand Fil... more Pakistan Journal of Biological Sciences, 2(4): 1415-1418,1999 Research Article, Low-cost Sand Filter For Domestic and Stockwater Use Jehan Zeb, M.Aslam, Shahid Ahmad and Aamir Kabir Water Resources Research Institute (WRRI), National Agricultural Research Center ...
Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfal... more Abstract A study was conducted at the WRRI-NARC, Islamabad under controlled conditions of rainfall and high temperatures to simulate hot-arid environment for establishment of plants like Eucalyptus camaldulensis and Acacia arabica in plastic bags [with an objective to ...
This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31... more This study revealed that the losses of water from the three watercourses were 27.11, 25.85 and 31.25 on total length basis and the losses on 100 meter length basis were 3.62, 3.15 and 4.47 percent, respectively. The conveyance efficiency worked out to be 72.89, 74.15 and 68.75 ...
Uploads
Papers by Shahid Ahmad