Khurram Khan | Sir Syed University of Engineering & Technology (original) (raw)
Papers by Khurram Khan
Numerical simulations of rectangular shape bubble column reactors (BCR) are validated starting fr... more Numerical simulations of rectangular shape bubble column reactors (BCR) are validated starting from preliminary simulations aimed at identifying proper simulation parameters for a given system and resulting up to the numerical simulation with mass transfer and chemical reactions. The transient, three dimensional simulations are carried out using FLUENT software and the results obtained for a system with low gas flow rate (48 L/h) indicated that we need enough fine mesh grid and appropriate closure of interfacial forces to predict reliably plume oscillation period, liquid axial velocity and gas holdup profiles. In case of high flow rate (260 L/h), we compared the results for the effect of different interfacial closure forces and change in inlet boundary condition for gas volume fraction. There is no change in hydrodynamic results when there is change in gas volume fraction at inlet boundary condition. The effect of virtual mass interfacial force on the simulation results is also negl...
With the increase in e-commerce and the digitisation of design data and inf ormation, the constru... more With the increase in e-commerce and the digitisation of design data and inf ormation, the construction sector has become reliant upon IT infrastructure and systems . The design and production process is more complex, more interconnected, and reliant upon greater information mobility, with seamless exchange of data and information in real time. Construction small and medium-sized enterprises (CSMEs), in particular, the speciality contractors, can effectively utilise cost-effective collaboration-en abling technologies, such as cloud computing, to help in the effective transfer of information and data to improve productivity. The system dynamics (SD) approach offers a perspective and tools to enable a better understanding of the dynamics of complex systems. This research focuses upon system dynamics methodology as a modelling and analysis tool in order to understand and identify the key drivers in the absorption of cloud computing for CSMEs. The aim of this paper is to determine ho w t...
Journal of Tourism and Services, 2019
The business environment is a profound concern for the state and institutions to make it encourag... more The business environment is a profound concern for the state and institutions to make it encouraging to boost entrepreneurship. Given such relevance of the business environment, this paper aims to link selected business environment aspects to business sector. The study identified the perceived differences between sectors in the Czech and Slovak Republics and then a comparison of a similar group of firms. To shape the study, survey-based research planned and conducted in two segments of firm’s (service and non-service), covered 641 enterprises. The current research adopted factor analysis and then t-test and Mann-Whitney test to determine the results. The major findings of the study reveal that the Slovak firms in the service sector scored higher in macroeconomic environment, consumers’ consumption and competition factors and lower in access to finance factor, as compared to their non-service counterparts. However, another key finding indicates that the Czech entrepreneurs’ perceptio...
Frontiers in surgery, 2017
The use of robots in surgery has become commonplace in many specialties. In this systematic revie... more The use of robots in surgery has become commonplace in many specialties. In this systematic review, we report on the current uses of robotics in plastic and reconstructive surgery and looks to future roles for robotics in this arena. A systematic literature search of Medline, EMBASE, and Scopus was performed using appropriate search terms in order to identify all applications of robot-assistance in plastic and reconstructive surgery. All articles were reviewed by two authors and a qualitative synthesis performed of those articles that met the inclusion criteria. The systematic review and results were conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines. A total of 7,904 articles were identified for title and abstract review. Sixty-eight studies met the inclusion criteria. Robotic assistance in plastic and reconstructive surgery is still in its infancy, with areas such as trans-oral robotic surgery and mi...
Journal of Applied Polymer Science, 1997
A liquid crystalline polymer (LCP) was synthesized by an interfacial polycondensation reaction at... more A liquid crystalline polymer (LCP) was synthesized by an interfacial polycondensation reaction at room temperature from terephthaloyl chloride and p,p-dihydroxydiphenyl sulfone. The LCP synthesized was so stable and molecularly rigid that it did not show any phase transition until it degraded at about 320ЊC. Composites of the LCP with polycarbonate (PC), polystyrene (PS), and sulfonated polystyrene (SPS) were formed by compression molding at a temperature at which the thermoplastic matrix was in the melt state. They were thermally analyzed by differential scanning calorimetry. Tensile specimens were cut from the compression-molded plates, and mechanical tests were performed. The morphology of the material systems was studied by performing scanning electron microscopy analysis on cryogenically fractured specimens. For LCP/PS and LCP/SPS systems, a sharp two-phase morphology was formed, which suggested poor interfacial adhesion. The tensile strength of both systems decreased with LCP addition. The LCP/PC system also revealed a two-phase morphology; however, the interfaces between the LCP domains and the PC matrix were not so well defined, showing better interfacial adhesion than the two previous systems studied. Stronger bonding between the LCP and PC resulted in a significant improvement in the mechanical behavior of PC by LCP addition.
Continuing Education in Anaesthesia Critical Care & Pain, 2014
Journal of Clinical Ultrasound, 2019
We report and discuss a case that illustrate the clinical utility of transcranial Doppler (TCD) u... more We report and discuss a case that illustrate the clinical utility of transcranial Doppler (TCD) ultrasound in a patient with cirrhosis. A 43-year-old female presented with acute decompensation of cirrhosis with hepatic encephalopathy, requiring mechanical ventilation. TCD showed low diastolic flow velocities and high pulsatility index (PI) consistent with increased cerebrovascular resistance (CVR). The flow velocities and PI normalized over a period of few days and correlated well with neurological improvement after treatment. Subsequently, the patient developed a large intracerebral hemorrhage with mass effect. The TCD measurements in intracranial hypertension were similar to those with cirrhosis and hepatic encephalopathy. However, the windkessel notch in the systolic phase of TCD waveform, related to the distensibility of arterial wall, was absent during raised intracranial pressure (ICP). The absence of a windkessel notch may help to differentiate a high downstream resistance due to raised ICP from increased CVR.
… & Advanced Surgical …, 2010
Roux-en-Y gastric bypass is an excellent option for weight loss in the morbidly obese. Unfortunat... more Roux-en-Y gastric bypass is an excellent option for weight loss in the morbidly obese. Unfortunately, some patients do have weight regain or insufficient weight loss. Revisional bariatric surgery is not without risk. Less invasive techniques may provide alternative treatments for patients that regain weight or have insufficient weight loss. This video demonstrates a technique of endoscopic sclerotherapy for dilated gastrojejunostomy after gastric bypass. The technique is applied to patients who have had weight regain or insufficient weight loss following gastric bypass. Patients who have lost the feeling of satiety, undergone reeducation and recounseling of dietary changes, and have documented dilated gastrojejunostomy on upper endoscopy and/or a barium study are offered this technique. If the gastojejunostomy is larger than 12 mm, sodium morrhuate is injected with an endoscopic needle circumferentially. The gastrojejunostomy is injected with 6-30 cc of sodium morrhuate. By visual inspection, the anastomosis usually appears smaller after the procedure. Most patients report a subjective feeling of satiety after the endoscopic sclerotherapy. Reinjection after 3 months has been performed in some patients. Except mild nausea, the patients have experienced no morbidity or mortality from the procedure. Endoscopic sclerotherapy may offer an alternative treatment for dilated gastrojejunostomy after gastric bypass. The technique described in the video is a relatively easy, safe method that may become the first line of therapy in patients who have a dilated gastrojejunostomy and have lost the feeling of satiety after gastric bypass with an associated weight gain.
Numerical simulations of rectangular shape bubble column reactors (BCR) are validated starting fr... more Numerical simulations of rectangular shape bubble column reactors (BCR) are validated starting from preliminary simulations aimed at identifying proper simulation parameters for a given system and resulting up to the numerical simulation with mass transfer and chemical reactions. The transient, three dimensional simulations are carried out using FLUENT software and the results obtained for a system with low gas flow rate (48 L/h) indicated that we need enough fine mesh grid and appropriate closure of interfacial forces to predict reliably plume oscillation period, liquid axial velocity and gas holdup profiles. In case of high flow rate (260 L/h), we compared the results for the effect of different interfacial closure forces and change in inlet boundary condition for gas volume fraction. There is no change in hydrodynamic results when there is change in gas volume fraction at inlet boundary condition. The effect of virtual mass interfacial force on the simulation results is also negl...
With the increase in e-commerce and the digitisation of design data and inf ormation, the constru... more With the increase in e-commerce and the digitisation of design data and inf ormation, the construction sector has become reliant upon IT infrastructure and systems . The design and production process is more complex, more interconnected, and reliant upon greater information mobility, with seamless exchange of data and information in real time. Construction small and medium-sized enterprises (CSMEs), in particular, the speciality contractors, can effectively utilise cost-effective collaboration-en abling technologies, such as cloud computing, to help in the effective transfer of information and data to improve productivity. The system dynamics (SD) approach offers a perspective and tools to enable a better understanding of the dynamics of complex systems. This research focuses upon system dynamics methodology as a modelling and analysis tool in order to understand and identify the key drivers in the absorption of cloud computing for CSMEs. The aim of this paper is to determine ho w t...
Journal of Tourism and Services, 2019
The business environment is a profound concern for the state and institutions to make it encourag... more The business environment is a profound concern for the state and institutions to make it encouraging to boost entrepreneurship. Given such relevance of the business environment, this paper aims to link selected business environment aspects to business sector. The study identified the perceived differences between sectors in the Czech and Slovak Republics and then a comparison of a similar group of firms. To shape the study, survey-based research planned and conducted in two segments of firm’s (service and non-service), covered 641 enterprises. The current research adopted factor analysis and then t-test and Mann-Whitney test to determine the results. The major findings of the study reveal that the Slovak firms in the service sector scored higher in macroeconomic environment, consumers’ consumption and competition factors and lower in access to finance factor, as compared to their non-service counterparts. However, another key finding indicates that the Czech entrepreneurs’ perceptio...
Frontiers in surgery, 2017
The use of robots in surgery has become commonplace in many specialties. In this systematic revie... more The use of robots in surgery has become commonplace in many specialties. In this systematic review, we report on the current uses of robotics in plastic and reconstructive surgery and looks to future roles for robotics in this arena. A systematic literature search of Medline, EMBASE, and Scopus was performed using appropriate search terms in order to identify all applications of robot-assistance in plastic and reconstructive surgery. All articles were reviewed by two authors and a qualitative synthesis performed of those articles that met the inclusion criteria. The systematic review and results were conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA) guidelines. A total of 7,904 articles were identified for title and abstract review. Sixty-eight studies met the inclusion criteria. Robotic assistance in plastic and reconstructive surgery is still in its infancy, with areas such as trans-oral robotic surgery and mi...
Journal of Applied Polymer Science, 1997
A liquid crystalline polymer (LCP) was synthesized by an interfacial polycondensation reaction at... more A liquid crystalline polymer (LCP) was synthesized by an interfacial polycondensation reaction at room temperature from terephthaloyl chloride and p,p-dihydroxydiphenyl sulfone. The LCP synthesized was so stable and molecularly rigid that it did not show any phase transition until it degraded at about 320ЊC. Composites of the LCP with polycarbonate (PC), polystyrene (PS), and sulfonated polystyrene (SPS) were formed by compression molding at a temperature at which the thermoplastic matrix was in the melt state. They were thermally analyzed by differential scanning calorimetry. Tensile specimens were cut from the compression-molded plates, and mechanical tests were performed. The morphology of the material systems was studied by performing scanning electron microscopy analysis on cryogenically fractured specimens. For LCP/PS and LCP/SPS systems, a sharp two-phase morphology was formed, which suggested poor interfacial adhesion. The tensile strength of both systems decreased with LCP addition. The LCP/PC system also revealed a two-phase morphology; however, the interfaces between the LCP domains and the PC matrix were not so well defined, showing better interfacial adhesion than the two previous systems studied. Stronger bonding between the LCP and PC resulted in a significant improvement in the mechanical behavior of PC by LCP addition.
Continuing Education in Anaesthesia Critical Care & Pain, 2014
Journal of Clinical Ultrasound, 2019
We report and discuss a case that illustrate the clinical utility of transcranial Doppler (TCD) u... more We report and discuss a case that illustrate the clinical utility of transcranial Doppler (TCD) ultrasound in a patient with cirrhosis. A 43-year-old female presented with acute decompensation of cirrhosis with hepatic encephalopathy, requiring mechanical ventilation. TCD showed low diastolic flow velocities and high pulsatility index (PI) consistent with increased cerebrovascular resistance (CVR). The flow velocities and PI normalized over a period of few days and correlated well with neurological improvement after treatment. Subsequently, the patient developed a large intracerebral hemorrhage with mass effect. The TCD measurements in intracranial hypertension were similar to those with cirrhosis and hepatic encephalopathy. However, the windkessel notch in the systolic phase of TCD waveform, related to the distensibility of arterial wall, was absent during raised intracranial pressure (ICP). The absence of a windkessel notch may help to differentiate a high downstream resistance due to raised ICP from increased CVR.
… & Advanced Surgical …, 2010
Roux-en-Y gastric bypass is an excellent option for weight loss in the morbidly obese. Unfortunat... more Roux-en-Y gastric bypass is an excellent option for weight loss in the morbidly obese. Unfortunately, some patients do have weight regain or insufficient weight loss. Revisional bariatric surgery is not without risk. Less invasive techniques may provide alternative treatments for patients that regain weight or have insufficient weight loss. This video demonstrates a technique of endoscopic sclerotherapy for dilated gastrojejunostomy after gastric bypass. The technique is applied to patients who have had weight regain or insufficient weight loss following gastric bypass. Patients who have lost the feeling of satiety, undergone reeducation and recounseling of dietary changes, and have documented dilated gastrojejunostomy on upper endoscopy and/or a barium study are offered this technique. If the gastojejunostomy is larger than 12 mm, sodium morrhuate is injected with an endoscopic needle circumferentially. The gastrojejunostomy is injected with 6-30 cc of sodium morrhuate. By visual inspection, the anastomosis usually appears smaller after the procedure. Most patients report a subjective feeling of satiety after the endoscopic sclerotherapy. Reinjection after 3 months has been performed in some patients. Except mild nausea, the patients have experienced no morbidity or mortality from the procedure. Endoscopic sclerotherapy may offer an alternative treatment for dilated gastrojejunostomy after gastric bypass. The technique described in the video is a relatively easy, safe method that may become the first line of therapy in patients who have a dilated gastrojejunostomy and have lost the feeling of satiety after gastric bypass with an associated weight gain.