Mehran University Research Journal of Engineering and Technology, 2012
In this paper, mechanism of liquefaction-related large settlements of the soil-structure system d... more In this paper, mechanism of liquefaction-related large settlements of the soil-structure system during the earthquake was studied using numerical modelling. The isolated shallow strip plane strain footing pad, supporting a typical simple frame structure, was founded on the ground at the shallow depth from the level ground surface. This system was modelled as plane-strain using the FLAC (Fast Lagrangian Analysis of continua) 2D dynamic modelling and analysis code. This case focuses on the basic mechanisms of liquefaction-induced large deformations of the structure during an earthquake and will provide a benchmark model case for comparison with the model case in which jet grouted columns are provided as ground reinforcement. The results showed that large settlements of shallow foundations in punching shear are triggered during cyclic excitation. These large settlements under the structure are driven by load of structure and earthquake excitation. Monotonic shear deformation, lateral s...
Mehran University Research Journal of Engineering and Technology, 2013
This paper addresses the significance of traveller information sources including mono-modal and m... more This paper addresses the significance of traveller information sources including mono-modal and multimodal websites for travel decisions. The research follows a decision paradigm developed earlier, involving an information acquisition process for travel choices, and identifies the abstract characteristics of new information sources that deserve further investigation (e.g. by incorporating these in models and studying their significance in model estimation). A Stated Preference experiment is developed and the utility functions are formulated by expanding the travellers' choice set to include different combinations of sources of information. In order to study the underlying choice mechanisms, the resulting variables are examined in models based on different behavioural strategies, including utility maximisation and minimising the regret associated with the foregone alternatives. This research confirmed that RRM (Random Regret Minimisation) Theory can fruitfully be used and can pro...
World Environmental and Water Resources Congress 2017, 2017
Unsafe drinking water is a major cause of disease in developing countries. Lack of adequate water... more Unsafe drinking water is a major cause of disease in developing countries. Lack of adequate water treatment and delivery infrastructure, high operational costs and poor maintenance are some of the factors contributing to the problem. Many developing countries also have large population clusters in cities and inadequate sanitation services, which increase the risk of water- borne disease outbreak. Incorporating renewable energy sources for treatment and distribution of potable water may be the key to developing sustainable water supply systems to reduce water- borne diseases in developing countries. This study focused on evaluating the potential of using distributed solar for a 4.5 million gallons per day (MGD) existing drinking water treatment plant (DWTP), located in Sindh, Pakistan. The DWTP utilized a conventional treatment train, consisting of coagulation, flocculation, sedimentation, filtration and disinfection processes to treat water obtained from the Indus River. The DWTP was sized by designing the various unit processes involved and then the energy consumption associated with each unit process was determined. The results showed that the energy consumption was largest for the flash and rapid mixers. Existing land holdings were sufficient for the deployment of solar photovoltaics (PV) which was successfully incorporated into the design of the DWTP
The properties of the Crumb Rubber Modified Bitumen (CRMB) are greatly influenced by the amount a... more The properties of the Crumb Rubber Modified Bitumen (CRMB) are greatly influenced by the amount and type of the material constituents used in the perpetration of the blend. Moreover, characteristics of the crumb rubber (CR) are modifier on the basis of processing mechanism is mainly found to govern the properties of the CRMB. A fair amount of research was observed in the literature on the bitumen modified by CR processed cryogenically and ambiently. However, little or no work has been done on the CR processed by the other methods such as the Aquablast processing technique, which is a relatively a new waste tyre rubber processing technique within the CR industry. In this study, influence of the scrap tyre fracture technique on the properties of CRMB blends was investigated by looking at viscosity with a Brookfield viscometer. The study allowed concluding that the amount of CR significantly influences the behavior of the blend. Based on the allowable limits of the specifications,...
Mehran University Research Journal of Engineering and Technology, 2013
In this paper, the liquefaction potential of medium dense and dense sand layers was studied by pe... more In this paper, the liquefaction potential of medium dense and dense sand layers was studied by performing constant volume (undrained) cyclic simple shear tests using cyclic simple shear apparatus. Straincontrolled approach was adopted. The liquefaction potential of two layers of a silty sand soil profile consisting of surface medium dense layer and underlying dense sand layers were studied. A medium dense sand surface layer exhibited flow type total liquefaction in cyclic loading in few cycles after initial liquefaction. An underlying dense sand base layer showed initial liquefaction in relatively more number of cycles and then cyclic mobility due to which pore pressure increases and decreases with cycles that is the characteristics of dense sand. The pore pressure increase and decrease is directly related to decrease and increase of effective stress.
Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences, 2021
The agricultural lands are being affected due to groundwater (GW) quality issues. To address th... more The agricultural lands are being affected due to groundwater (GW) quality issues. To address this worldwide problematic situation, various irrigation studies have been practiced to identify the effects on the soil conditions. The current study has been designed to assess the GW quality and soil salinity/sodicity by different irrigation techniques in the remote mountainous area of Jamshoro district at Gul Muhammad Khaskheli farm Thana Boula Khan. The experimental plot was designed under furrow, pitcher and poly ethylene bag irrigation system. These soil characteristics indicated that the drain-ability of the soil was high, with an infiltration rate of 1.60 cm/h and water holding capacity was low. Water samples were collected at each irrigation time from sowing to harvest. The soil understudy was non-saline (ECe < 4.0 dS/m) and non-sodic (pH < 8.0, SAR < 7.5 and ESP < 15.0) before crop sowing in all the three methods of irrigation at all the three sampling depths, i.e., ...
An effort has been made to optimally determine the status of turbulence loss coefficient in the p... more An effort has been made to optimally determine the status of turbulence loss coefficient in the present study. The parameter is identified in the framework of GA (Genetic Algorithm), which consequently resulted in the development of a computer model. In accordance with principles of the GA, the objective function, sse (sum of square of errors), is minimized between 0.009785 and 0.017565; as a result the well hydraulic parameters are optimally identified. To check validity of the model, simulated draw downs are compared against the observed ones, which indicate mean difference between them varying from 0.0049m to 0.0124m. Furthermore, validity of the model is also endorsed through statistical analysis with model efficiency varying between 99.97 and 100.00%. The model is applied to 5 data sets of step drawdown pumping test, yielding 5 values of turbulence coefficient varying between 1.01 and 2.08. Out of these 5 optimized values of turbulence coefficient none of the values is equal to...
The validation of a numerical model is done using Computational Fluid Dynamics (CFD) commercial ... more The validation of a numerical model is done using Computational Fluid Dynamics (CFD) commercial software ANSYS CFX. Six trapezoidal channels which were used by Tominaga et al. (1989) in their experimental studies are modelled. Special emphasis is done on the distribution of shear stress and secondary currents. The channels have the sidewall inclinations of 30o, 46o and 58o to the vertical. The bottom width of the trapezoidal channels is kept constant for each slant angle and only the depth is varied to get different aspect ratios. The roughness on the boundaries is also varied. The results are compared with the published results found in the literature. The results are quiet encouraging and the model may therefore be used with confidence for other similar studies.
Irrigation water quality plays a vital role in sustaining crop productivity and feeding a growing... more Irrigation water quality plays a vital role in sustaining crop productivity and feeding a growing world population. In many countries, continued agricultural water reuse can lead to greater water-soluble salt concentrations, and in particular Na; finding means by which irrigation water Na, and thus sodium adsorption ratios (SAR), can be reduced would reduce the rate at which soil sodification occurs. Four biochars, containing a variety of organic functional groups and electrochemistries, were examined for their potential to sorb and remove Na from simulated irrigation water, and subsequently reduce water SAR. Two batch experiments examined the role that wheat straw biochar, lodgepole pine biochar, Kentucky bluegrass biochar, and hemp biochar played in terms of sorbing sodium over time or application rate. Of the four biochars examined, hemp biochar had the lowest oxidation–reduction potential (ORP; ~ 0–100 mV), sorbed the greatest Na amount (up to 923 mg kg−1), and released Ca and M...
This article explores the water policy narrative in Pakistan, and identifies its historical traje... more This article explores the water policy narrative in Pakistan, and identifies its historical trajectories and influences, as well as the impact of the global agenda setting of water for 2030. For this purpose, water sector reforms in Pakistan are examined as a case study. The National Water Policy (NWP) 2018 and Participatory Irrigation Management (PIM) reforms are critically evaluated and loopholes identified, in terms of both theoretical aspects and constraints in their practical implementation. The overall analysis reveals that the engineering narrative is dominant in policy circles and large-scale infrastructure construction is seen as an exceptional measure to overcome the current loss of storage potential due to sedimentation. On the other hand, the adoption of the Integrated Water Resource Management (IWRM) framework reflects the desire of state institutions to imbue water policy reform with international credibility. The IWRM framework has been adopted as isomorphic mimicry t...
Investigating the trends in the major climatic variables over the Upper Indus Basin (UIB) region ... more Investigating the trends in the major climatic variables over the Upper Indus Basin (UIB) region is difficult for many reasons, including highly complex terrain with heterogeneous spatial precipitation patterns and a scarcity of gauge stations. The Weather Research and Forecasting (WRF) model was applied to simulate the spatiotemporal variability of precipitation and temperature over the Indus Basin from 2000 through 2015 with boundary conditions derived from the Climate Forecast System Reanalysis (CFSR) data. The WRF model was configured with three nested domains (d01–d03) with horizontal resolutions increasing inward from 36 km to 12 km to 4 km horizontal resolution, respectively. These simulations were a continuous run with a spin-up year (i.e., 2000) to equilibrate the soil moisture, snow cover, and temperature at the beginning of the simulation. The simulations were then compared with TRMM and station data for the same time period using root mean squared error (RMSE), percentag...
Mehran University Research Journal of Engineering and Technology, 2019
The present study indicates the potential projected variation of decadal mean rainfall over Kohis... more The present study indicates the potential projected variation of decadal mean rainfall over Kohistan region of Sindh Province, Pakistan. Precipitation variability is a crucial climatic factor that affects human health and their settlements. In this study, the precipitation variability associated with climate change in Kohistan region, Sindh, Pakistan is simulated using the PRECIS regional climate modeling system. The study analyses the precipitation variability in the future for two spells (2021-2050 and 20712099) with respect to the past (1961-1990) climate under the baseline ECHAM5 dataset for A1B Scenario at a resolution of 25x25 km. Based on this analyses, the precipitation scarcity is projected for 2021-2050 and 2071-2099 decades. The projected results showed a serious precipitation variation and shortfall of 12.60, 53.98, and 48.19% during 2031-2040,2041-2050 and 2081-2090 decades respectively as compared to baseline (1961-1990). The analyzed situation would be harmful to the ...
In the wake of a rapidly changing climate, droughts have intensified, in both duration and severi... more In the wake of a rapidly changing climate, droughts have intensified, in both duration and severity, across the globe. The Germanwatch long-term Climate Risk Index ranks Pakistan among the top 10 countries most affected by the adverse effects of climate change. Within Pakistan, the province of Balochistan is among the most vulnerable regions due to recurring prolonged droughts, erratic precipitation patterns, and dependence on agriculture and livestock for survival. This study aims to explore how the characteristics of droughts have evolved in the region from 1902–2015 using 3-month and 12-month timescales of a popular drought index, the Standardized Precipitation Evapotranspiration Index (SPEI). The region was divided into six zones using Spatial “K”luster Analysis using Tree Edge Removal (SKATER) method, and run theory was applied to characterize droughts in terms of duration, severity, intensity, and peak. The results of the non-parametric Mann–Kendall trend test applied to SPEI ...
Pakistan is among the top ten countries adversely affected by climate change. More specifically, ... more Pakistan is among the top ten countries adversely affected by climate change. More specifically, there is concern that climate change may cause longer and severer spells of droughts. To quantify the change in the characteristics of droughts in Pakistan over the years, we have evaluated spatio-temporal trends of droughts in Pakistan over the period 1902–2015 using Standardized Precipitation Evapotranspiration Index (SPEI). Additionally, the Spatial “K” luster Analysis using Tree Edge Removal (SKATER) method was employed to regionalize droughts into five contiguous zones. The run theory was then applied to each zone to identify drought events and characterize them in terms of duration, severity, intensity, and peak. Moreover, the Modified Mann–Kendall trend test was applied to identify statistically significant trends in SPEI and drought characteristics in each zone. It was found that the southern areas of Pakistan, encompassing Sindh and most of Baluchistan, have experienced a decrea...
Mehran University Research Journal of Engineering and Technology, 2012
In this paper, mechanism of liquefaction-related large settlements of the soil-structure system d... more In this paper, mechanism of liquefaction-related large settlements of the soil-structure system during the earthquake was studied using numerical modelling. The isolated shallow strip plane strain footing pad, supporting a typical simple frame structure, was founded on the ground at the shallow depth from the level ground surface. This system was modelled as plane-strain using the FLAC (Fast Lagrangian Analysis of continua) 2D dynamic modelling and analysis code. This case focuses on the basic mechanisms of liquefaction-induced large deformations of the structure during an earthquake and will provide a benchmark model case for comparison with the model case in which jet grouted columns are provided as ground reinforcement. The results showed that large settlements of shallow foundations in punching shear are triggered during cyclic excitation. These large settlements under the structure are driven by load of structure and earthquake excitation. Monotonic shear deformation, lateral s...
Mehran University Research Journal of Engineering and Technology, 2013
This paper addresses the significance of traveller information sources including mono-modal and m... more This paper addresses the significance of traveller information sources including mono-modal and multimodal websites for travel decisions. The research follows a decision paradigm developed earlier, involving an information acquisition process for travel choices, and identifies the abstract characteristics of new information sources that deserve further investigation (e.g. by incorporating these in models and studying their significance in model estimation). A Stated Preference experiment is developed and the utility functions are formulated by expanding the travellers' choice set to include different combinations of sources of information. In order to study the underlying choice mechanisms, the resulting variables are examined in models based on different behavioural strategies, including utility maximisation and minimising the regret associated with the foregone alternatives. This research confirmed that RRM (Random Regret Minimisation) Theory can fruitfully be used and can pro...
World Environmental and Water Resources Congress 2017, 2017
Unsafe drinking water is a major cause of disease in developing countries. Lack of adequate water... more Unsafe drinking water is a major cause of disease in developing countries. Lack of adequate water treatment and delivery infrastructure, high operational costs and poor maintenance are some of the factors contributing to the problem. Many developing countries also have large population clusters in cities and inadequate sanitation services, which increase the risk of water- borne disease outbreak. Incorporating renewable energy sources for treatment and distribution of potable water may be the key to developing sustainable water supply systems to reduce water- borne diseases in developing countries. This study focused on evaluating the potential of using distributed solar for a 4.5 million gallons per day (MGD) existing drinking water treatment plant (DWTP), located in Sindh, Pakistan. The DWTP utilized a conventional treatment train, consisting of coagulation, flocculation, sedimentation, filtration and disinfection processes to treat water obtained from the Indus River. The DWTP was sized by designing the various unit processes involved and then the energy consumption associated with each unit process was determined. The results showed that the energy consumption was largest for the flash and rapid mixers. Existing land holdings were sufficient for the deployment of solar photovoltaics (PV) which was successfully incorporated into the design of the DWTP
The properties of the Crumb Rubber Modified Bitumen (CRMB) are greatly influenced by the amount a... more The properties of the Crumb Rubber Modified Bitumen (CRMB) are greatly influenced by the amount and type of the material constituents used in the perpetration of the blend. Moreover, characteristics of the crumb rubber (CR) are modifier on the basis of processing mechanism is mainly found to govern the properties of the CRMB. A fair amount of research was observed in the literature on the bitumen modified by CR processed cryogenically and ambiently. However, little or no work has been done on the CR processed by the other methods such as the Aquablast processing technique, which is a relatively a new waste tyre rubber processing technique within the CR industry. In this study, influence of the scrap tyre fracture technique on the properties of CRMB blends was investigated by looking at viscosity with a Brookfield viscometer. The study allowed concluding that the amount of CR significantly influences the behavior of the blend. Based on the allowable limits of the specifications,...
Mehran University Research Journal of Engineering and Technology, 2013
In this paper, the liquefaction potential of medium dense and dense sand layers was studied by pe... more In this paper, the liquefaction potential of medium dense and dense sand layers was studied by performing constant volume (undrained) cyclic simple shear tests using cyclic simple shear apparatus. Straincontrolled approach was adopted. The liquefaction potential of two layers of a silty sand soil profile consisting of surface medium dense layer and underlying dense sand layers were studied. A medium dense sand surface layer exhibited flow type total liquefaction in cyclic loading in few cycles after initial liquefaction. An underlying dense sand base layer showed initial liquefaction in relatively more number of cycles and then cyclic mobility due to which pore pressure increases and decreases with cycles that is the characteristics of dense sand. The pore pressure increase and decrease is directly related to decrease and increase of effective stress.
Pakistan Journal of Scientific & Industrial Research Series A: Physical Sciences, 2021
The agricultural lands are being affected due to groundwater (GW) quality issues. To address th... more The agricultural lands are being affected due to groundwater (GW) quality issues. To address this worldwide problematic situation, various irrigation studies have been practiced to identify the effects on the soil conditions. The current study has been designed to assess the GW quality and soil salinity/sodicity by different irrigation techniques in the remote mountainous area of Jamshoro district at Gul Muhammad Khaskheli farm Thana Boula Khan. The experimental plot was designed under furrow, pitcher and poly ethylene bag irrigation system. These soil characteristics indicated that the drain-ability of the soil was high, with an infiltration rate of 1.60 cm/h and water holding capacity was low. Water samples were collected at each irrigation time from sowing to harvest. The soil understudy was non-saline (ECe < 4.0 dS/m) and non-sodic (pH < 8.0, SAR < 7.5 and ESP < 15.0) before crop sowing in all the three methods of irrigation at all the three sampling depths, i.e., ...
An effort has been made to optimally determine the status of turbulence loss coefficient in the p... more An effort has been made to optimally determine the status of turbulence loss coefficient in the present study. The parameter is identified in the framework of GA (Genetic Algorithm), which consequently resulted in the development of a computer model. In accordance with principles of the GA, the objective function, sse (sum of square of errors), is minimized between 0.009785 and 0.017565; as a result the well hydraulic parameters are optimally identified. To check validity of the model, simulated draw downs are compared against the observed ones, which indicate mean difference between them varying from 0.0049m to 0.0124m. Furthermore, validity of the model is also endorsed through statistical analysis with model efficiency varying between 99.97 and 100.00%. The model is applied to 5 data sets of step drawdown pumping test, yielding 5 values of turbulence coefficient varying between 1.01 and 2.08. Out of these 5 optimized values of turbulence coefficient none of the values is equal to...
The validation of a numerical model is done using Computational Fluid Dynamics (CFD) commercial ... more The validation of a numerical model is done using Computational Fluid Dynamics (CFD) commercial software ANSYS CFX. Six trapezoidal channels which were used by Tominaga et al. (1989) in their experimental studies are modelled. Special emphasis is done on the distribution of shear stress and secondary currents. The channels have the sidewall inclinations of 30o, 46o and 58o to the vertical. The bottom width of the trapezoidal channels is kept constant for each slant angle and only the depth is varied to get different aspect ratios. The roughness on the boundaries is also varied. The results are compared with the published results found in the literature. The results are quiet encouraging and the model may therefore be used with confidence for other similar studies.
Irrigation water quality plays a vital role in sustaining crop productivity and feeding a growing... more Irrigation water quality plays a vital role in sustaining crop productivity and feeding a growing world population. In many countries, continued agricultural water reuse can lead to greater water-soluble salt concentrations, and in particular Na; finding means by which irrigation water Na, and thus sodium adsorption ratios (SAR), can be reduced would reduce the rate at which soil sodification occurs. Four biochars, containing a variety of organic functional groups and electrochemistries, were examined for their potential to sorb and remove Na from simulated irrigation water, and subsequently reduce water SAR. Two batch experiments examined the role that wheat straw biochar, lodgepole pine biochar, Kentucky bluegrass biochar, and hemp biochar played in terms of sorbing sodium over time or application rate. Of the four biochars examined, hemp biochar had the lowest oxidation–reduction potential (ORP; ~ 0–100 mV), sorbed the greatest Na amount (up to 923 mg kg−1), and released Ca and M...
This article explores the water policy narrative in Pakistan, and identifies its historical traje... more This article explores the water policy narrative in Pakistan, and identifies its historical trajectories and influences, as well as the impact of the global agenda setting of water for 2030. For this purpose, water sector reforms in Pakistan are examined as a case study. The National Water Policy (NWP) 2018 and Participatory Irrigation Management (PIM) reforms are critically evaluated and loopholes identified, in terms of both theoretical aspects and constraints in their practical implementation. The overall analysis reveals that the engineering narrative is dominant in policy circles and large-scale infrastructure construction is seen as an exceptional measure to overcome the current loss of storage potential due to sedimentation. On the other hand, the adoption of the Integrated Water Resource Management (IWRM) framework reflects the desire of state institutions to imbue water policy reform with international credibility. The IWRM framework has been adopted as isomorphic mimicry t...
Investigating the trends in the major climatic variables over the Upper Indus Basin (UIB) region ... more Investigating the trends in the major climatic variables over the Upper Indus Basin (UIB) region is difficult for many reasons, including highly complex terrain with heterogeneous spatial precipitation patterns and a scarcity of gauge stations. The Weather Research and Forecasting (WRF) model was applied to simulate the spatiotemporal variability of precipitation and temperature over the Indus Basin from 2000 through 2015 with boundary conditions derived from the Climate Forecast System Reanalysis (CFSR) data. The WRF model was configured with three nested domains (d01–d03) with horizontal resolutions increasing inward from 36 km to 12 km to 4 km horizontal resolution, respectively. These simulations were a continuous run with a spin-up year (i.e., 2000) to equilibrate the soil moisture, snow cover, and temperature at the beginning of the simulation. The simulations were then compared with TRMM and station data for the same time period using root mean squared error (RMSE), percentag...
Mehran University Research Journal of Engineering and Technology, 2019
The present study indicates the potential projected variation of decadal mean rainfall over Kohis... more The present study indicates the potential projected variation of decadal mean rainfall over Kohistan region of Sindh Province, Pakistan. Precipitation variability is a crucial climatic factor that affects human health and their settlements. In this study, the precipitation variability associated with climate change in Kohistan region, Sindh, Pakistan is simulated using the PRECIS regional climate modeling system. The study analyses the precipitation variability in the future for two spells (2021-2050 and 20712099) with respect to the past (1961-1990) climate under the baseline ECHAM5 dataset for A1B Scenario at a resolution of 25x25 km. Based on this analyses, the precipitation scarcity is projected for 2021-2050 and 2071-2099 decades. The projected results showed a serious precipitation variation and shortfall of 12.60, 53.98, and 48.19% during 2031-2040,2041-2050 and 2081-2090 decades respectively as compared to baseline (1961-1990). The analyzed situation would be harmful to the ...
In the wake of a rapidly changing climate, droughts have intensified, in both duration and severi... more In the wake of a rapidly changing climate, droughts have intensified, in both duration and severity, across the globe. The Germanwatch long-term Climate Risk Index ranks Pakistan among the top 10 countries most affected by the adverse effects of climate change. Within Pakistan, the province of Balochistan is among the most vulnerable regions due to recurring prolonged droughts, erratic precipitation patterns, and dependence on agriculture and livestock for survival. This study aims to explore how the characteristics of droughts have evolved in the region from 1902–2015 using 3-month and 12-month timescales of a popular drought index, the Standardized Precipitation Evapotranspiration Index (SPEI). The region was divided into six zones using Spatial “K”luster Analysis using Tree Edge Removal (SKATER) method, and run theory was applied to characterize droughts in terms of duration, severity, intensity, and peak. The results of the non-parametric Mann–Kendall trend test applied to SPEI ...
Pakistan is among the top ten countries adversely affected by climate change. More specifically, ... more Pakistan is among the top ten countries adversely affected by climate change. More specifically, there is concern that climate change may cause longer and severer spells of droughts. To quantify the change in the characteristics of droughts in Pakistan over the years, we have evaluated spatio-temporal trends of droughts in Pakistan over the period 1902–2015 using Standardized Precipitation Evapotranspiration Index (SPEI). Additionally, the Spatial “K” luster Analysis using Tree Edge Removal (SKATER) method was employed to regionalize droughts into five contiguous zones. The run theory was then applied to each zone to identify drought events and characterize them in terms of duration, severity, intensity, and peak. Moreover, the Modified Mann–Kendall trend test was applied to identify statistically significant trends in SPEI and drought characteristics in each zone. It was found that the southern areas of Pakistan, encompassing Sindh and most of Baluchistan, have experienced a decrea...
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Papers by Kamran Ansari