Nihat Baysal | Rensselaer Polytechnic Institute (original) (raw)

Papers by Nihat Baysal

Research paper thumbnail of Carbon Dioxide Sequestration by Single Walled Carbon Nanotubes

Research paper thumbnail of General Chemistry Laboratory Manual – Techniques and Experiments

Research paper thumbnail of Modular organization of cardiovascular disease related protein interaction network

Research paper thumbnail of Factors Predicting the Performance of Engineering Students: A Case Study From Yeditepe University

icee.usm.edu

The relationship between the precollege profile of engineering students and their cumulative grad... more The relationship between the precollege profile of engineering students and their cumulative grade point average (CGPA) in a Turkish private university is investigated in the present study. A dataset including information on student background and scores in university entrance exams for the last four years is used. The models used in this work are selected primarily to examine the relationship between CGPA and the ranking in the university entrance exam. Other factors of interest are attendance to university provided language prep school, scholarship status and gender of the student, and the type and the region of the high school the student had graduated. The results show that ranking in college entrance exams is a statistically significant predictor of college GPA. All else equal, the results also suggest that girls are more successful than boys. Another result of this research is the association between scholarship status and CGPA. The source of tuition scholarship arises as a significant predictor of CGPA as much as the student's tuition status. One unexpected result of this study is the importance of regional background of the student. Freshman engineering students from other regions do not perform as well as freshman students who attended regional high schools. In time, this discrepancy disappears, but not completely.

Research paper thumbnail of A novel method to detect pressure-induced sensor attenuations (PISA) in an artificial pancreas

Continuous glucose monitors (CGMs) provide real-time interstitial glucose concentrations that are... more Continuous glucose monitors (CGMs) provide real-time interstitial glucose concentrations that are essential for automated treatment of individuals with type 1 diabetes. Miscalibration, noise spikes, dropouts, or pressure applied to the site (e.g., lying on the site while sleeping) can cause inaccurate glucose signals, which could lead to inappropriate insulin dosing decisions. These studies focus on the problem of pressure-induced sensor attenuations (PISAs) that occur overnight and can cause undesirable pump shut-offs in a predictive low glucose suspend system. The algorithm presented here uses real-time CGM readings without knowledge of meals, insulin doses, activity, sensor recalibrations, or fingerstick measurements. The real-time PISA detection technique was tested on outpatient “in-home” data from a predictive low-glucose suspend trial with over 1125 nights of data. A total of 178 sets were created by using different parameters for the PISA detection algorithm to illustrate its range of available performance. The tracings were reviewed via a web-based analysis tool by an engineer with an extensive expertise on analyzing clinical datasets and ~3% of the CGM readings were marked as PISA events which were used as the gold standard. It is shown that 88.34% of the PISAs were successfully detected by the algorithm, and the percentage of false detections could be reduced to 1.70% by altering the algorithm parameters. Use of the proposed PISA detection method can result in a significant decrease in undesirable pump suspensions overnight, and may lead to lower overnight mean glucose levels while still achieving a low risk of hypoglycemia.

Research paper thumbnail of Kinematics of Polymer Chains in Dense Media. 3. Influence of Intramolecular Conformational Potentials

Macromolecules, 1995

The previously developed theory for treating the kinematics of polymers in dense media (Bahar, I.... more The previously developed theory for treating the kinematics of polymers in dense media (Bahar, I.; Erman, B.; Monnerie, L. Macromolecules 1992, 25, 6309, 6315) is extended to include the influence of internal conformational energy barriers on the mechanism of motion. The method is based on the solution of a constrained equation of motion in the presence of dissipative forces due to friction. Successive solution of the equation for incremental changes in bond torsional angles up to completing one isomeric jump yields the optimal configurational rearrangements of chains of known original structure in response to bond isomerization. By repeating the method for an ensemble of Monte Carlo chains with different original conformations, the type and extent of coupling between dihedral angles, the correlation length involved in local conformational transitions, and the effective activation energies operating on a wide spectrum of viscous environments are determined as a function of the relative strength of intraand intermolecular effects. Comparison of results with those of Brownian dynamics simulations supports the adoption of the present model as a computationally efficient approach for investigating the kinematics of local motions in polymers.

Research paper thumbnail of Capture and release of carbon dioxide by carbon nanotubes via temperature cycling

Carbon nanotubes (CNTs) received remarkable attention since they were shown to possess many uniqu... more Carbon nanotubes (CNTs) received remarkable attention since they were shown to possess many unique properties as well as being effective and stable adsorbent materials that make them potentially useful for gas storage and separation of various gas mixtures. In this study, the effect of temperature variations on carbon dioxide (CO2) capture via single walled carbon nanotubes (SWNTs) and multi walled carbon nanotubes (MWNTs) were investigated with molecular dynamics simulations. SWNTs of type (10,10), (15,15), and (20,20) and MWNTs formed from the combination of these were simulated. The temperature was varied between 300 and 360 K. The results suggest that absorption of CO2 into the CNTs were directly related to the internal volume of the nanotube, but the cross-sectional area of the tube entrance had a significant effect on the number of CO2 molecules retained. The number of CO2 molecules collected in CNTs gradually decreases with increasing temperature. Separate simulations were performed to understand the potential use of CNTs as thermal pumps to collect/discharge CO2 molecules via temperature cycling.

Research paper thumbnail of A Network Representation of Households by Health Exclusion, Poverty, and Unemployment

Procedia - Social and Behavioral Sciences, 2011

Social exclusion, emphasized in the European Social Agenda, presents an interesting case study on... more Social exclusion, emphasized in the European Social Agenda, presents an interesting case study on the discussion of universal vs. means-tested social policies. To understand the conditions under which universal policies may have an advantage over means-tested policies, we propose a method of network representation in which partitions are detected by background characteristics of the households. Using non-relational household level data from three countries, we map the association between exclusion from health care, unemployment and poverty. Our results show that households are less likely to form homogeneous partitioning by poverty and health care exclusion profiles, compared to the partitioning formed by poverty and unemployment characteristics. The results suggest that in cases where identifying beneficiaries is difficult, illustrated by heterogeneous partitioning, universal coverage offers an advantage over means-tested social policies.

Research paper thumbnail of A Computational Study on Carbon Dioxide Storage in Single Walled Carbon Nanotubes

Research paper thumbnail of Adaptation of Professional Skills in the Unit Operations Laboratory

Research paper thumbnail of A novel integrative network approach to understand the interplay between cardiovascular disease and other complex disorders

Research paper thumbnail of Carbon Dioxide Sequestration by Carbon Nanotubes: Application of Graph Theoretical Approach

Computational Materials Science, Jan 1, 2010

A graph theoretical approach is applied to analyze the dynamic evolution of retention of carbon d... more A graph theoretical approach is applied to analyze the dynamic evolution of retention of carbon dioxide (CO 2 ) molecules in single-walled carbon nanotubes (SWNTs). The trajectories of the molecules were obtained from the Molecular Dynamics (MD) simulations performed at ...

Research paper thumbnail of Factors Predicting the Performance of Engineering Students: A Case Study From Yeditepe University

Research paper thumbnail of Interaction of Surface Modified Carbon Nanotubes With Supercritical Carbon Dioxide

APS Meeting Abstracts, Jan 1, 2006

The properties of carbon nanotube (CNT)-polymer nanocomposites are far below than those calculate... more The properties of carbon nanotube (CNT)-polymer nanocomposites are far below than those calculated, mainly due to poor dispersion or interface quality. This is particularly difficult for single walled carbon nanotubes (SWNTs) as they tend to form bundles or ropes that are difficult ...

Research paper thumbnail of Carbon Dioxide Sequestration by Single Walled Carbon Nanotubes

Research paper thumbnail of General Chemistry Laboratory Manual – Techniques and Experiments

Research paper thumbnail of Modular organization of cardiovascular disease related protein interaction network

Research paper thumbnail of Factors Predicting the Performance of Engineering Students: A Case Study From Yeditepe University

icee.usm.edu

The relationship between the precollege profile of engineering students and their cumulative grad... more The relationship between the precollege profile of engineering students and their cumulative grade point average (CGPA) in a Turkish private university is investigated in the present study. A dataset including information on student background and scores in university entrance exams for the last four years is used. The models used in this work are selected primarily to examine the relationship between CGPA and the ranking in the university entrance exam. Other factors of interest are attendance to university provided language prep school, scholarship status and gender of the student, and the type and the region of the high school the student had graduated. The results show that ranking in college entrance exams is a statistically significant predictor of college GPA. All else equal, the results also suggest that girls are more successful than boys. Another result of this research is the association between scholarship status and CGPA. The source of tuition scholarship arises as a significant predictor of CGPA as much as the student's tuition status. One unexpected result of this study is the importance of regional background of the student. Freshman engineering students from other regions do not perform as well as freshman students who attended regional high schools. In time, this discrepancy disappears, but not completely.

Research paper thumbnail of A novel method to detect pressure-induced sensor attenuations (PISA) in an artificial pancreas

Continuous glucose monitors (CGMs) provide real-time interstitial glucose concentrations that are... more Continuous glucose monitors (CGMs) provide real-time interstitial glucose concentrations that are essential for automated treatment of individuals with type 1 diabetes. Miscalibration, noise spikes, dropouts, or pressure applied to the site (e.g., lying on the site while sleeping) can cause inaccurate glucose signals, which could lead to inappropriate insulin dosing decisions. These studies focus on the problem of pressure-induced sensor attenuations (PISAs) that occur overnight and can cause undesirable pump shut-offs in a predictive low glucose suspend system. The algorithm presented here uses real-time CGM readings without knowledge of meals, insulin doses, activity, sensor recalibrations, or fingerstick measurements. The real-time PISA detection technique was tested on outpatient “in-home” data from a predictive low-glucose suspend trial with over 1125 nights of data. A total of 178 sets were created by using different parameters for the PISA detection algorithm to illustrate its range of available performance. The tracings were reviewed via a web-based analysis tool by an engineer with an extensive expertise on analyzing clinical datasets and ~3% of the CGM readings were marked as PISA events which were used as the gold standard. It is shown that 88.34% of the PISAs were successfully detected by the algorithm, and the percentage of false detections could be reduced to 1.70% by altering the algorithm parameters. Use of the proposed PISA detection method can result in a significant decrease in undesirable pump suspensions overnight, and may lead to lower overnight mean glucose levels while still achieving a low risk of hypoglycemia.

Research paper thumbnail of Kinematics of Polymer Chains in Dense Media. 3. Influence of Intramolecular Conformational Potentials

Macromolecules, 1995

The previously developed theory for treating the kinematics of polymers in dense media (Bahar, I.... more The previously developed theory for treating the kinematics of polymers in dense media (Bahar, I.; Erman, B.; Monnerie, L. Macromolecules 1992, 25, 6309, 6315) is extended to include the influence of internal conformational energy barriers on the mechanism of motion. The method is based on the solution of a constrained equation of motion in the presence of dissipative forces due to friction. Successive solution of the equation for incremental changes in bond torsional angles up to completing one isomeric jump yields the optimal configurational rearrangements of chains of known original structure in response to bond isomerization. By repeating the method for an ensemble of Monte Carlo chains with different original conformations, the type and extent of coupling between dihedral angles, the correlation length involved in local conformational transitions, and the effective activation energies operating on a wide spectrum of viscous environments are determined as a function of the relative strength of intraand intermolecular effects. Comparison of results with those of Brownian dynamics simulations supports the adoption of the present model as a computationally efficient approach for investigating the kinematics of local motions in polymers.

Research paper thumbnail of Capture and release of carbon dioxide by carbon nanotubes via temperature cycling

Carbon nanotubes (CNTs) received remarkable attention since they were shown to possess many uniqu... more Carbon nanotubes (CNTs) received remarkable attention since they were shown to possess many unique properties as well as being effective and stable adsorbent materials that make them potentially useful for gas storage and separation of various gas mixtures. In this study, the effect of temperature variations on carbon dioxide (CO2) capture via single walled carbon nanotubes (SWNTs) and multi walled carbon nanotubes (MWNTs) were investigated with molecular dynamics simulations. SWNTs of type (10,10), (15,15), and (20,20) and MWNTs formed from the combination of these were simulated. The temperature was varied between 300 and 360 K. The results suggest that absorption of CO2 into the CNTs were directly related to the internal volume of the nanotube, but the cross-sectional area of the tube entrance had a significant effect on the number of CO2 molecules retained. The number of CO2 molecules collected in CNTs gradually decreases with increasing temperature. Separate simulations were performed to understand the potential use of CNTs as thermal pumps to collect/discharge CO2 molecules via temperature cycling.

Research paper thumbnail of A Network Representation of Households by Health Exclusion, Poverty, and Unemployment

Procedia - Social and Behavioral Sciences, 2011

Social exclusion, emphasized in the European Social Agenda, presents an interesting case study on... more Social exclusion, emphasized in the European Social Agenda, presents an interesting case study on the discussion of universal vs. means-tested social policies. To understand the conditions under which universal policies may have an advantage over means-tested policies, we propose a method of network representation in which partitions are detected by background characteristics of the households. Using non-relational household level data from three countries, we map the association between exclusion from health care, unemployment and poverty. Our results show that households are less likely to form homogeneous partitioning by poverty and health care exclusion profiles, compared to the partitioning formed by poverty and unemployment characteristics. The results suggest that in cases where identifying beneficiaries is difficult, illustrated by heterogeneous partitioning, universal coverage offers an advantage over means-tested social policies.

Research paper thumbnail of A Computational Study on Carbon Dioxide Storage in Single Walled Carbon Nanotubes

Research paper thumbnail of Adaptation of Professional Skills in the Unit Operations Laboratory

Research paper thumbnail of A novel integrative network approach to understand the interplay between cardiovascular disease and other complex disorders

Research paper thumbnail of Carbon Dioxide Sequestration by Carbon Nanotubes: Application of Graph Theoretical Approach

Computational Materials Science, Jan 1, 2010

A graph theoretical approach is applied to analyze the dynamic evolution of retention of carbon d... more A graph theoretical approach is applied to analyze the dynamic evolution of retention of carbon dioxide (CO 2 ) molecules in single-walled carbon nanotubes (SWNTs). The trajectories of the molecules were obtained from the Molecular Dynamics (MD) simulations performed at ...

Research paper thumbnail of Factors Predicting the Performance of Engineering Students: A Case Study From Yeditepe University

Research paper thumbnail of Interaction of Surface Modified Carbon Nanotubes With Supercritical Carbon Dioxide

APS Meeting Abstracts, Jan 1, 2006

The properties of carbon nanotube (CNT)-polymer nanocomposites are far below than those calculate... more The properties of carbon nanotube (CNT)-polymer nanocomposites are far below than those calculated, mainly due to poor dispersion or interface quality. This is particularly difficult for single walled carbon nanotubes (SWNTs) as they tend to form bundles or ropes that are difficult ...