2018 18th International Conference on Harmonics and Quality of Power (ICHQP), 2018
The penetration of Distributed Energy Resources (DERs) continues to blur the boundary between the... more The penetration of Distributed Energy Resources (DERs) continues to blur the boundary between the traditionally held definitions of transmission and distribution systems. Increasingly, DERs are being connected at the sub-transmission and distribution voltage levels. As is the case with any new technology, the proliferation of such generation resources has led to certain unforeseen outcomes. This paper examines the effect on the power system (with regards to power quality), of the transformers that are being used to integrate DERs to the system. Two case studies from two different utilities in the United States, pertaining to Solar PV transformer energization are presented. One case study pertains to transformer energization and system unbalance leading to harmonic resonance issues while the other shows distortion around the zero crossing of the voltage caused by ringing during energization of PV transformers connected to solar inverters. A third, simulation case study examines PV transformer energization that excites resonance in systems containing transmission cables. Detailed analyses of the phenomena, underlying causes and mitigation techniques are presented. Finally, shortcomings with respect to modeling techniques and lessons learned in the process have been described. The paper closes with a description of future research avenues and expected work with regards to Power Quality in this field.
Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and m... more Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and microbe interactions. RH shows a fast apical growth, constituting a unique single cell model system to analyse cellular morphodynamics. In this context, live cell imaging using microfluidics recently developed to analyze root development is appealing, but highresolution imaging is still lacking to study accurate spatiotemporal morphodynamics of organelles. Here, we provide a powerful coverslip based microfluidic device (CMD) which enables uso capture high resolution confocal imaging of Arabidopsis RH development with real-time monitoring of nuclear movement and shape changes. To validate the setup, we confirmed the typical RH growth rates and the mean nuclear positioning previously reported with classical methods. Moreover, in order to illustrate the possibilities offered by the CMD, we have compared the real-time variations in the circularity, area, and aspect ratio of nuclei moving in growing and mature RH. Interestingly, we observed higher aspect ratios in the nuclei of mature RH, correlating with higher speeds of nuclear migration. This observation opens the way for further investigations of the effect of mechanical constraints on nuclear shape changes during RH growth and nuclear migration and its role in RH and plant development. References Agudelo, C.G., Sanati, A., Ghanbari, M., Packirisamy, M. and Geitmann, A. (2012) A microfluidic platform for the investigation of elongation growth in pollen tubes. J.
The majority of online users do not engage highly with services that are offered via Web. This is... more The majority of online users do not engage highly with services that are offered via Web. This is a well-known fact and it is also one of the main issues that personalization algorithms try to overcome. A popular way of personalizing an online service is to record users' actions into user profiles. Weakly-engaged users lead to sparsely populated user profiles, or weak profiles as we name them. Such weak profiles constitute a source of potential increase in user engagement and as a consequence, windfall profits for Internet companies. In this paper, we define the novel problem of enhancing weak profiles in positive space and propose an effective solution based on learning collective embedding space in order to capture a low-dimensional manifold designed to specifically reconstruct sparse user profiles. Our method consistently outperforms baselines consisting of kNN and collective factorization without constraints on user profile. Experiments on two datasets, news and video, from a popular online portal show improvements of up to more than 100 % in terms of MAP for extremely weak profiles, and up to around 10 % for moderately weak profiles. In order to evaluate the impact of our method on learned latent space embeddings for users and items, we generate recommendations exploiting our user profile constrained approach. The generated recommendations outperform state-of-the-art techniques based on lowrank collective matrix factorization in particular for users that clicked at most four times (78-82 % of the total) on the items published by the online portal we consider.
2016 Twenty Second National Conference on Communication (NCC), 2016
Network debugging has always been a challenging task primarily because the original design of the... more Network debugging has always been a challenging task primarily because the original design of the Internet architecture gave little importance to debugging and management. In addition, the Internet makes forwarding decisions in a distributed manner, which is hard to track. With the advent of Software Defined Networks (SDNs), network debugging has potentially become easier because solely the control plane makes forwarding decisions, which is often centrally located. In this paper, we propose Control-plane Only Scalable Efficient and Lightweight SDN Debugger (CoSEL), which is to the best of our knowledge the first control-plane only, network debugger for SDN. Unlike earlier proposed debuggers, which rely on information specially obtained from the data-plane or a combination of the data and control planes, CoSEL does not require the use of any additional network bandwidth for its operation and hence outperforms existing schemes in terms of scalability. In terms of completeness, however, CoSEL does not perform as well as some existing schemes, although this loss in completeness does not prevent it from capturing most of the bugs in the network, which hav 1 e been observed to be caused mainly by the control plane. We implement CoSEL on the Floodlight controller as a network application and present results of CoSEL in action over a network emulated by mininet. However, CoSEL is controller independent and utilizes a common programming API provided by POX, NOX and OpenDaylight. In addition, the control plane debugging of CoSEL enables it to be an effective debugging tool for network applications that are built on top of controllers utilizing Northbound APIs and interacting with network by injecting rules.
An AlCrCuNiFeCo high entropy alloy (HEA), which has simple face centered cubic (FCC) and body cen... more An AlCrCuNiFeCo high entropy alloy (HEA), which has simple face centered cubic (FCC) and body centered cubic (BCC) solid solution phases as the microstructural constituents, was processed and its high temperature deformation behaviour was examined as a function of temperature (700e1030 C) and strain rate (10 À3 e10 À1 s À1), so as to identify the optimum thermo-mechanical processing (TMP) conditions for hot working of this alloy. For this purpose, power dissipation efficiency and deformation instability maps utilizing that the dynamic materials model pioneered by Prasad and co-workers have been generated and examined. Various deformation mechanisms, which operate in different temperatureestrain rate regimes, were identified with the aid of the maps and complementary microstructural analysis of the deformed specimens. Results indicate two distinct deformation domains within the range of experimental conditions examined, with the combination of 1000 C/10 À3 s À1 and 1030 C/10 À2 s À1 being the optimum for hot working. Flow instabilities associated with adiabatic shear banding, or localized plastic flow, and or cracking were found for 700e730 C/10 À3 e10 À1 s À1 and 750e860 C/10 À1.4 e10 À1 s À1 combinations. A constitutive equation that describes the flow stress of AlCrCuNiFeCo alloy as a function of strain rate and deformation temperature was also determined.
2014 IEEE PES General Meeting | Conference & Exposition, 2014
Single phase capacitor run induction motors have long held a significant presence in the distribu... more Single phase capacitor run induction motors have long held a significant presence in the distribution system because of their use in domestic appliances such as refrigerators, air conditioners and fans. Because they are so widespread in number, their characteristics and response towards harmonic voltages present in single phase distribution systems are important. This paper outlines the response of these motors to harmonic voltages in some detail. It explains how the auxiliary winding circuit in these motors causes certain behaviors not normally associated with single winding run motors. This paper provides some background to understanding this behavior and then provides experimental demonstration for the peculiar phenomena that occur when the motor is subjected to a source voltage containing harmonics.
2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology, 2008
Abstract We consider a collaborative scheduling problem motivated by mining in remote off-grid ar... more Abstract We consider a collaborative scheduling problem motivated by mining in remote off-grid areas. In our model, jobs are assigned to processors who each have their own machine for executing them. As each job needs a certain amount of a resource shared between the processors, a coordination mechanism between the processors is needed. We present a framework which collaboratively computes a schedule while exchanging only limited information between the processors and a central resource manager. Our computational ...
Kafkas Universitesi Veteriner Fakultesi Dergisi, 2015
The present study was conducted with the objective to determine the effect of bull exposure on po... more The present study was conducted with the objective to determine the effect of bull exposure on postpartum resumption of ovarian activity, first behavioural oestrus and conception rate in Cholistani cows. A total of 24 Cholistani cows kept at Shadabad Cooperative Livestock Farms Cholistan, Pakistan during September-2012 to January-2013, were divided into two groups. Bull exposed (BE) cows (n=18) were exposed to mature bull throughout the study period whereas bull not exposed (BNE) cows (n=6) were not. Both groups were kept under similar feeding and management conditions. The mean interval from the calving to resumption of ovarian activity was 39.75±3.19 days in the BE and 49.75±2.75 days in BNE animals (P<0.05). The mean interval from the calving to the first behavioural oestrus was 46.93±0.48 days in BE and 57.5±1.29 days in BNE animals (P<0.05). During the study period, more (P<0.05) cows from the BE group (16/18 = 88.88%) showed behavioural oestrus as compared to the BNE group ones (4/6=66.66%). The conception rate in BE and BNE cows were 66.66% and 33.33%, respectively (P<0.05). It was concluded that, cows exposed to the presence of bulls at early postpartum periods showed reduced intervals from the calving to resumption of ovarian activity, first behavioural oestrus and resumed cyclicity earlier.
Background: Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play imp... more Background: Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant's adaptation to abiotic stress. Methodology: The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses-salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results: The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions: Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress responsive elements. The 3D structure showed functional similarity with sterol glycosyltransferases.
We consider a scheduling problem motivated by mining in remote off-grid areas. In this model, min... more We consider a scheduling problem motivated by mining in remote off-grid areas. In this model, mines have pre-assigned mineral processing jobs and their own machine for executing these jobs. Each job also needs a certain amount of electricity in order to get completed. The electricity, on the other hand, is of limited supply and must be shared between the mines. We present a mathematical formulation of the problem and a Lagrangian relaxation based heuristic. Computational results which compares our heuristic with genetic algorithm and simulated annealing are also presented.
ABSTRACT Addition of boron to cast Ti–6Al–4V alloy leads to significant refinement in grain size,... more ABSTRACT Addition of boron to cast Ti–6Al–4V alloy leads to significant refinement in grain size, which in turn improves processibilty as well as the mechanical properties of the as-cast alloy. Room temperature tensile and fatigue properties of Wrought Ti–6Al–4V–B alloys with B up to 0.09 wt.% are investigated. Thermo-mechanical processing at 950 °C caused kinking of α lamellae and alignment of TiB particles in the flow direction with a negligible change in prior β grain and colony sizes, indicating the absence of dynamic recrystallisation during forging. Characterisation with the aid of X-ray and electron back scattered diffraction reveal a strong basal texture in B free alloy which gets randomised with the 0.09B addition in the forged condition. Marginal enhancement in tensile and fatigue properties upon forging is noted. B free wrought Ti–6Al–4V alloy exhibits better tensile strength as compared to B containing alloy, due to the operation of 〈c + a〉 slip on pyramidal planes with high value of CRSS as compared to 〈a〉 slip on basal and prismatic planes. Decrease in fatigue strength of Ti–6Al–4V–0.04B in as-cast and the wrought state is observed due to increase in the volume fraction of grain boundary α phase with B addition, which acts as a crack nucleation site. No significant effect of TiB particles on tensile and fatigue properties is observed.
Trace addition of B to Ti and its alloys leads to a marked microstructural refinement, which in t... more Trace addition of B to Ti and its alloys leads to a marked microstructural refinement, which in turn enhances the tensile and fatigue properties of the as-cast alloys. This can be particularly advantageous in applications wherein Ti alloys are used in the as-cast form. In some of these, the environment containing H and Ti alloy components is susceptible to embrittlement due to H uptake. Whether the addition of B to Ti-6Al-4V improves the relative mechanical performance of such cast components used in H environments is examined in this work. Cast Ti-6Al-4V-xB (0≤x≤0.55 wt%) alloys were H charged at 500 and 700 1C for up to 4 h. Microstructures and room temperature tensile properties of the resulting alloys have been evaluated. Experimental results show that charging at 700 1C for 2 h leads to the formation of titanium hydride in the microstructure, which in turn causes severe embrittlement. For shorter durations of charging, a marginal increase in strength was noted, which is attributed to the solid solution strengthening by H. The mechanical performance of the B modified alloys was found to be relatively higher, implying that B addition not only refines the as-cast microstructure but also is beneficial in applications that involve H environment. A direct correlation between the volume fraction of TiB particles in the microstructure and the relative reduction in the strength of H-embrittled alloys suggests that the addition of B to Ti alloys, in optimum quantities, can be utilized as a strategy to design alloys that are more resistant to H embrittlement.
International Journal of Production Economics, 2013
Abstract We consider a scheduling problem arising in the mining industry. Ore from several mining... more Abstract We consider a scheduling problem arising in the mining industry. Ore from several mining sites must be transferred to ports to be loaded on ships in a timely manner. In doing so, several constraints must be met which involve transporting the ore and deadlines. These deadlines are two-fold; there is a preferred deadline by which the ships should be loaded and there is a final deadline by which time the ships must be loaded. Corresponding to the two types of deadlines, each task is associated with a soft and hard due time. The ...
Abstract The Brucker-Garey-Johnson algorithm and Hu's algorithm are based on the idea of th... more Abstract The Brucker-Garey-Johnson algorithm and Hu's algorithm are based on the idea of the critical path method and were developed for the model with unit execution time tasks, precedence constraints and parallel identical processors. The performance guarantees for these algorithms have been presented in Singh and Zinder (2000a, 2000b). We present upper bounds for the Brucker-Garey-Johnson algorithm with communication delays, which can be seen as a generalization of the performance guarantees in Singh and Zinder ( ...
2018 18th International Conference on Harmonics and Quality of Power (ICHQP), 2018
The penetration of Distributed Energy Resources (DERs) continues to blur the boundary between the... more The penetration of Distributed Energy Resources (DERs) continues to blur the boundary between the traditionally held definitions of transmission and distribution systems. Increasingly, DERs are being connected at the sub-transmission and distribution voltage levels. As is the case with any new technology, the proliferation of such generation resources has led to certain unforeseen outcomes. This paper examines the effect on the power system (with regards to power quality), of the transformers that are being used to integrate DERs to the system. Two case studies from two different utilities in the United States, pertaining to Solar PV transformer energization are presented. One case study pertains to transformer energization and system unbalance leading to harmonic resonance issues while the other shows distortion around the zero crossing of the voltage caused by ringing during energization of PV transformers connected to solar inverters. A third, simulation case study examines PV transformer energization that excites resonance in systems containing transmission cables. Detailed analyses of the phenomena, underlying causes and mitigation techniques are presented. Finally, shortcomings with respect to modeling techniques and lessons learned in the process have been described. The paper closes with a description of future research avenues and expected work with regards to Power Quality in this field.
Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and m... more Root hairs (RHs) are tubular extensions of root epidermal cells that favour nutrient uptake and microbe interactions. RH shows a fast apical growth, constituting a unique single cell model system to analyse cellular morphodynamics. In this context, live cell imaging using microfluidics recently developed to analyze root development is appealing, but highresolution imaging is still lacking to study accurate spatiotemporal morphodynamics of organelles. Here, we provide a powerful coverslip based microfluidic device (CMD) which enables uso capture high resolution confocal imaging of Arabidopsis RH development with real-time monitoring of nuclear movement and shape changes. To validate the setup, we confirmed the typical RH growth rates and the mean nuclear positioning previously reported with classical methods. Moreover, in order to illustrate the possibilities offered by the CMD, we have compared the real-time variations in the circularity, area, and aspect ratio of nuclei moving in growing and mature RH. Interestingly, we observed higher aspect ratios in the nuclei of mature RH, correlating with higher speeds of nuclear migration. This observation opens the way for further investigations of the effect of mechanical constraints on nuclear shape changes during RH growth and nuclear migration and its role in RH and plant development. References Agudelo, C.G., Sanati, A., Ghanbari, M., Packirisamy, M. and Geitmann, A. (2012) A microfluidic platform for the investigation of elongation growth in pollen tubes. J.
The majority of online users do not engage highly with services that are offered via Web. This is... more The majority of online users do not engage highly with services that are offered via Web. This is a well-known fact and it is also one of the main issues that personalization algorithms try to overcome. A popular way of personalizing an online service is to record users' actions into user profiles. Weakly-engaged users lead to sparsely populated user profiles, or weak profiles as we name them. Such weak profiles constitute a source of potential increase in user engagement and as a consequence, windfall profits for Internet companies. In this paper, we define the novel problem of enhancing weak profiles in positive space and propose an effective solution based on learning collective embedding space in order to capture a low-dimensional manifold designed to specifically reconstruct sparse user profiles. Our method consistently outperforms baselines consisting of kNN and collective factorization without constraints on user profile. Experiments on two datasets, news and video, from a popular online portal show improvements of up to more than 100 % in terms of MAP for extremely weak profiles, and up to around 10 % for moderately weak profiles. In order to evaluate the impact of our method on learned latent space embeddings for users and items, we generate recommendations exploiting our user profile constrained approach. The generated recommendations outperform state-of-the-art techniques based on lowrank collective matrix factorization in particular for users that clicked at most four times (78-82 % of the total) on the items published by the online portal we consider.
2016 Twenty Second National Conference on Communication (NCC), 2016
Network debugging has always been a challenging task primarily because the original design of the... more Network debugging has always been a challenging task primarily because the original design of the Internet architecture gave little importance to debugging and management. In addition, the Internet makes forwarding decisions in a distributed manner, which is hard to track. With the advent of Software Defined Networks (SDNs), network debugging has potentially become easier because solely the control plane makes forwarding decisions, which is often centrally located. In this paper, we propose Control-plane Only Scalable Efficient and Lightweight SDN Debugger (CoSEL), which is to the best of our knowledge the first control-plane only, network debugger for SDN. Unlike earlier proposed debuggers, which rely on information specially obtained from the data-plane or a combination of the data and control planes, CoSEL does not require the use of any additional network bandwidth for its operation and hence outperforms existing schemes in terms of scalability. In terms of completeness, however, CoSEL does not perform as well as some existing schemes, although this loss in completeness does not prevent it from capturing most of the bugs in the network, which hav 1 e been observed to be caused mainly by the control plane. We implement CoSEL on the Floodlight controller as a network application and present results of CoSEL in action over a network emulated by mininet. However, CoSEL is controller independent and utilizes a common programming API provided by POX, NOX and OpenDaylight. In addition, the control plane debugging of CoSEL enables it to be an effective debugging tool for network applications that are built on top of controllers utilizing Northbound APIs and interacting with network by injecting rules.
An AlCrCuNiFeCo high entropy alloy (HEA), which has simple face centered cubic (FCC) and body cen... more An AlCrCuNiFeCo high entropy alloy (HEA), which has simple face centered cubic (FCC) and body centered cubic (BCC) solid solution phases as the microstructural constituents, was processed and its high temperature deformation behaviour was examined as a function of temperature (700e1030 C) and strain rate (10 À3 e10 À1 s À1), so as to identify the optimum thermo-mechanical processing (TMP) conditions for hot working of this alloy. For this purpose, power dissipation efficiency and deformation instability maps utilizing that the dynamic materials model pioneered by Prasad and co-workers have been generated and examined. Various deformation mechanisms, which operate in different temperatureestrain rate regimes, were identified with the aid of the maps and complementary microstructural analysis of the deformed specimens. Results indicate two distinct deformation domains within the range of experimental conditions examined, with the combination of 1000 C/10 À3 s À1 and 1030 C/10 À2 s À1 being the optimum for hot working. Flow instabilities associated with adiabatic shear banding, or localized plastic flow, and or cracking were found for 700e730 C/10 À3 e10 À1 s À1 and 750e860 C/10 À1.4 e10 À1 s À1 combinations. A constitutive equation that describes the flow stress of AlCrCuNiFeCo alloy as a function of strain rate and deformation temperature was also determined.
2014 IEEE PES General Meeting | Conference & Exposition, 2014
Single phase capacitor run induction motors have long held a significant presence in the distribu... more Single phase capacitor run induction motors have long held a significant presence in the distribution system because of their use in domestic appliances such as refrigerators, air conditioners and fans. Because they are so widespread in number, their characteristics and response towards harmonic voltages present in single phase distribution systems are important. This paper outlines the response of these motors to harmonic voltages in some detail. It explains how the auxiliary winding circuit in these motors causes certain behaviors not normally associated with single winding run motors. This paper provides some background to understanding this behavior and then provides experimental demonstration for the peculiar phenomena that occur when the motor is subjected to a source voltage containing harmonics.
2008 IEEE/WIC/ACM International Conference on Web Intelligence and Intelligent Agent Technology, 2008
Abstract We consider a collaborative scheduling problem motivated by mining in remote off-grid ar... more Abstract We consider a collaborative scheduling problem motivated by mining in remote off-grid areas. In our model, jobs are assigned to processors who each have their own machine for executing them. As each job needs a certain amount of a resource shared between the processors, a coordination mechanism between the processors is needed. We present a framework which collaboratively computes a schedule while exchanging only limited information between the processors and a central resource manager. Our computational ...
Kafkas Universitesi Veteriner Fakultesi Dergisi, 2015
The present study was conducted with the objective to determine the effect of bull exposure on po... more The present study was conducted with the objective to determine the effect of bull exposure on postpartum resumption of ovarian activity, first behavioural oestrus and conception rate in Cholistani cows. A total of 24 Cholistani cows kept at Shadabad Cooperative Livestock Farms Cholistan, Pakistan during September-2012 to January-2013, were divided into two groups. Bull exposed (BE) cows (n=18) were exposed to mature bull throughout the study period whereas bull not exposed (BNE) cows (n=6) were not. Both groups were kept under similar feeding and management conditions. The mean interval from the calving to resumption of ovarian activity was 39.75±3.19 days in the BE and 49.75±2.75 days in BNE animals (P<0.05). The mean interval from the calving to the first behavioural oestrus was 46.93±0.48 days in BE and 57.5±1.29 days in BNE animals (P<0.05). During the study period, more (P<0.05) cows from the BE group (16/18 = 88.88%) showed behavioural oestrus as compared to the BNE group ones (4/6=66.66%). The conception rate in BE and BNE cows were 66.66% and 33.33%, respectively (P<0.05). It was concluded that, cows exposed to the presence of bulls at early postpartum periods showed reduced intervals from the calving to resumption of ovarian activity, first behavioural oestrus and resumed cyclicity earlier.
Background: Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play imp... more Background: Sterol glycosyltrnasferases (SGT) are enzymes that glycosylate sterols which play important role in plant adaptation to stress and are medicinally important in plants like Withania somnifera. The present study aims to find the role of WsSGTL1 which is a sterol glycosyltransferase from W. somnifera, in plant's adaptation to abiotic stress. Methodology: The WsSGTL1 gene was transformed in Arabidopsis thaliana through Agrobacterium mediated transformation, using the binary vector pBI121, by floral dip method. The phenotypic and physiological parameters like germination, root length, shoot weight, relative electrolyte conductivity, MDA content, SOD levels, relative electrolyte leakage and chlorophyll measurements were compared between transgenic and wild type Arabidopsis plants under different abiotic stresses-salt, heat and cold. Biochemical analysis was done by HPLC-TLC and radiolabelled enzyme assay. The promoter of the WsSGTL1 gene was cloned by using Genome Walker kit (Clontech, USA) and the 3D structures were predicted by using Discovery Studio Ver. 2.5. Results: The WsSGTL1 transgenic plants were confirmed to be single copy by Southern and homozygous by segregation analysis. As compared to WT, the transgenic plants showed better germination, salt tolerance, heat and cold tolerance. The level of the transgene WsSGTL1 was elevated in heat, cold and salt stress along with other marker genes such as HSP70, HSP90, RD29, SOS3 and LEA4-5. Biochemical analysis showed the formation of sterol glycosides and increase in enzyme activity. When the promoter of WsSGTL1 gene was cloned from W. somnifera and sequenced, it contained stress responsive elements. Bioinformatics analysis of the 3D structure of the WsSGTL1 protein showed functional similarity with sterol glycosyltransferase AtSGT of A. thaliana. Conclusions: Transformation of WsSGTL1 gene in A. thaliana conferred abiotic stress tolerance. The promoter of the gene in W.somnifera was found to have stress responsive elements. The 3D structure showed functional similarity with sterol glycosyltransferases.
We consider a scheduling problem motivated by mining in remote off-grid areas. In this model, min... more We consider a scheduling problem motivated by mining in remote off-grid areas. In this model, mines have pre-assigned mineral processing jobs and their own machine for executing these jobs. Each job also needs a certain amount of electricity in order to get completed. The electricity, on the other hand, is of limited supply and must be shared between the mines. We present a mathematical formulation of the problem and a Lagrangian relaxation based heuristic. Computational results which compares our heuristic with genetic algorithm and simulated annealing are also presented.
ABSTRACT Addition of boron to cast Ti–6Al–4V alloy leads to significant refinement in grain size,... more ABSTRACT Addition of boron to cast Ti–6Al–4V alloy leads to significant refinement in grain size, which in turn improves processibilty as well as the mechanical properties of the as-cast alloy. Room temperature tensile and fatigue properties of Wrought Ti–6Al–4V–B alloys with B up to 0.09 wt.% are investigated. Thermo-mechanical processing at 950 °C caused kinking of α lamellae and alignment of TiB particles in the flow direction with a negligible change in prior β grain and colony sizes, indicating the absence of dynamic recrystallisation during forging. Characterisation with the aid of X-ray and electron back scattered diffraction reveal a strong basal texture in B free alloy which gets randomised with the 0.09B addition in the forged condition. Marginal enhancement in tensile and fatigue properties upon forging is noted. B free wrought Ti–6Al–4V alloy exhibits better tensile strength as compared to B containing alloy, due to the operation of 〈c + a〉 slip on pyramidal planes with high value of CRSS as compared to 〈a〉 slip on basal and prismatic planes. Decrease in fatigue strength of Ti–6Al–4V–0.04B in as-cast and the wrought state is observed due to increase in the volume fraction of grain boundary α phase with B addition, which acts as a crack nucleation site. No significant effect of TiB particles on tensile and fatigue properties is observed.
Trace addition of B to Ti and its alloys leads to a marked microstructural refinement, which in t... more Trace addition of B to Ti and its alloys leads to a marked microstructural refinement, which in turn enhances the tensile and fatigue properties of the as-cast alloys. This can be particularly advantageous in applications wherein Ti alloys are used in the as-cast form. In some of these, the environment containing H and Ti alloy components is susceptible to embrittlement due to H uptake. Whether the addition of B to Ti-6Al-4V improves the relative mechanical performance of such cast components used in H environments is examined in this work. Cast Ti-6Al-4V-xB (0≤x≤0.55 wt%) alloys were H charged at 500 and 700 1C for up to 4 h. Microstructures and room temperature tensile properties of the resulting alloys have been evaluated. Experimental results show that charging at 700 1C for 2 h leads to the formation of titanium hydride in the microstructure, which in turn causes severe embrittlement. For shorter durations of charging, a marginal increase in strength was noted, which is attributed to the solid solution strengthening by H. The mechanical performance of the B modified alloys was found to be relatively higher, implying that B addition not only refines the as-cast microstructure but also is beneficial in applications that involve H environment. A direct correlation between the volume fraction of TiB particles in the microstructure and the relative reduction in the strength of H-embrittled alloys suggests that the addition of B to Ti alloys, in optimum quantities, can be utilized as a strategy to design alloys that are more resistant to H embrittlement.
International Journal of Production Economics, 2013
Abstract We consider a scheduling problem arising in the mining industry. Ore from several mining... more Abstract We consider a scheduling problem arising in the mining industry. Ore from several mining sites must be transferred to ports to be loaded on ships in a timely manner. In doing so, several constraints must be met which involve transporting the ore and deadlines. These deadlines are two-fold; there is a preferred deadline by which the ships should be loaded and there is a final deadline by which time the ships must be loaded. Corresponding to the two types of deadlines, each task is associated with a soft and hard due time. The ...
Abstract The Brucker-Garey-Johnson algorithm and Hu's algorithm are based on the idea of th... more Abstract The Brucker-Garey-Johnson algorithm and Hu's algorithm are based on the idea of the critical path method and were developed for the model with unit execution time tasks, precedence constraints and parallel identical processors. The performance guarantees for these algorithms have been presented in Singh and Zinder (2000a, 2000b). We present upper bounds for the Brucker-Garey-Johnson algorithm with communication delays, which can be seen as a generalization of the performance guarantees in Singh and Zinder ( ...
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Papers by Gaurav Singh