Analytical modelling of Early Voltage (and Common Emitter Current Gain (β) of Heterojunction Bipo... more Analytical modelling of Early Voltage (and Common Emitter Current Gain (β) of Heterojunction Bipolar Transistor (HBT) are derived considering field dependent mobility, doping dependent mobility, Band Gap Narrowing (BGN), changes in density of state (DOS) and velocity saturation effect. BGN was considered due to heavy doping and presence of Germanium. The effect of various base doping profiles (Gaussian, exponential and uniform) and germanium profile (trapezoidal/triangular/box) on V A and β are addressed. The results of the analysis are compared with the data available in the previous research work.
Escherichia coli O157:H7 is a predominant serotype of Shiga toxin producing E. coli (STEC) and is... more Escherichia coli O157:H7 is a predominant serotype of Shiga toxin producing E. coli (STEC) and is responsible for many outbreaks worldwide. Until recently, there is no comparative study on the bovine and clinical isolates as no STEC O157:H7 has been isolated from patients in Bangladesh. In the present study, the local bovine isolates were compared with a reference clinical strain to investigate whether the bovine isolates are capable of producing same degree of illness as the clinical strain. Two local isolates (CD-11 and CD-17) of bovine origin and a reference clinical strain (E. coli O157:H7 NCTC 12079) were investigated for the presence of virulence genes by polymerase chain reaction (PCR), Shiga toxin production by VTEC-RPLA, invasive property by Congo red binding and Sereny’s keratoconjunctivitis, and other enterotoxic, cytotoxic and mouse lethal activities. Both the local isolates and the reference clinical strain showed the presence of eae and stx2 genes and were found to be ...
The object of the present work is to establish a foundation for the design and manufacturing of c... more The object of the present work is to establish a foundation for the design and manufacturing of composite materials for combined mechanical, thermal, and electrical applied conditions. The present paper will discuss a new non-invasive interrogation method for establishing not only internal integrity but also the nature and distribution of internal material structure and defect morphology changes by applying broadband dielectric spectroscopy to detect conductivity and permittivity changes during the history of loading. Interpretations of the results by analysis of discrete local details, and by the introduction of a generalized compliance method will be presented. Prognosis methods based on the technique will also be discussed. Data and examples of application of the method for woven glass reinforced polymer matrix materials will be presented. Opportunities for application of the method to design for durability in multi-physics applications will be identified.
The present paper is concerned with heterogeneous materials in which the mor-phology is specifica... more The present paper is concerned with heterogeneous materials in which the mor-phology is specifically designed to achieve functional properties. These materials, or mate-rial systems, are found in energy systems such as fuel cells and batteries, but also in aeronau-tical structures such as the conductive skins of commercial airplanes which have polymer composite primary structures. Many of these heterogeneous materials are dielectric and, under certain conditions, conductive. Charge transport and storage in such materials is typi-cally discussed in terms of equivalent (electrical) circuits, without recourse to first principles physics or mechanics. The present paper discusses the transport and storage properties of several examples of such materials from a computational standpoint, and compares some critical predictions with experimental data. Opportunities and needs for improving our un-derstandings and computational capabilities for this class of problems will also be discussed.
2011 International Conference on Electronic Devices, Systems and Applications (ICEDSA), 2011
This paper presents a modified Valley-Fill (VF) ballast circuit to combine with a current fed res... more This paper presents a modified Valley-Fill (VF) ballast circuit to combine with a current fed resonant inverter as the power circuit for a high power factor VF electronic ballast. The original VF circuit permit input current conduction from 30 o to 150 o , and then from 210 o to 330 o . Due to this discontinuity, high total harmonic
ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 2, 2010
ABSTRACT In the present work, we are concerned with heterogeneous material systems that have mult... more ABSTRACT In the present work, we are concerned with heterogeneous material systems that have multiple distinct materials and void phases, and associated interfaces, for which the geometric scale and specific morphology at the micro/nano-level play an essential role in the global properties, functional behavior, and material system performance. Such materials are at the heart of revolutionary advances in devices that convert and store energy (e.g., batteries, fuel cells, solar cells, capacitors, and many electro-optical devices), and other membrane-based devices used in chemical and fuel processing, sequestration, and extraction. In recent years, advances in a variety of additive manufacturing methods and techniques have made it possible to design, control, and fabricate specific micro- or nano-structure to achieve prescriptive functional performance of the material systems and devices in which they appear. However, systematic multiphysics analysis methods properly set on field equations that represent the local details is not available, so that first-principles understandings and designs of those materials are not properly founded. Recently, the doe established an energy frontiers research center for physics based nanostructure design and fabrication of hetero geneous f unctional m aterials, called the HeteroFoaM center, to address this and related questions. The present paper presents some initial findings of part of that effort related specifically to morphology. For the present study, a finite element model (FEM) was developed Using COMSOL MULTIPHYSICS to predict impedance behavior when the field equations are set on the local features of regular geometric micro-structures The results for are compared with experimental data obtained from impedance spectroscopy of single SOFC fuel cell elements. For the model, equivalent idealized geometric structures were assumed corresponding to the YSZ material morphology of the fuel cell. Continuously aligned pore structures were represented by rectangular extrusions and regular porosity was represented by geometric shapes such as circles, rectangles and triangles. For experimental data, fragments of a button cell were used with silver paste contacts on the electrodes. For the model, the geometric microstructure was varied by using different shapes i.e. circles, rectangles and triangles while keeping the total material quantity constant, and by using equivalent areas for each of the geometric shapes. Impedance response for the frequency range from 1Hz to 1MHz was obtained for both the models and the experiments. Observations and interpretations of morphology effects are presented.
Abstract. We present the NOVA Workflow tool-suite, a prototype for a process, information and com... more Abstract. We present the NOVA Workflow tool-suite, a prototype for a process, information and communication management tool to guide and inform real world workflows with special attention to the needs of health services delivery. NOVA Workflow is an innovative ...
Page 120. Model checking workflow monitors and its application to a pain management process Fazle... more Page 120. Model checking workflow monitors and its application to a pain management process Fazle Rabbi, Ahmed Shah Mashiyat, and Wendy MacCaull Centre for Logic and Information St. Francis Xavier University {rfazle, x2008ooc, wmaccaul}@ stfx. ca Abstract. ...
Over the years, researchers have investigated how to provide better support for hospital administ... more Over the years, researchers have investigated how to provide better support for hospital administration, therapy and laboratory workflows. Among these efforts, as with any other safety critical system, reliability of the workflows is a key issue. In this paper, we provide a ...
Analytical modelling of Early Voltage (and Common Emitter Current Gain (β) of Heterojunction Bipo... more Analytical modelling of Early Voltage (and Common Emitter Current Gain (β) of Heterojunction Bipolar Transistor (HBT) are derived considering field dependent mobility, doping dependent mobility, Band Gap Narrowing (BGN), changes in density of state (DOS) and velocity saturation effect. BGN was considered due to heavy doping and presence of Germanium. The effect of various base doping profiles (Gaussian, exponential and uniform) and germanium profile (trapezoidal/triangular/box) on V A and β are addressed. The results of the analysis are compared with the data available in the previous research work.
Escherichia coli O157:H7 is a predominant serotype of Shiga toxin producing E. coli (STEC) and is... more Escherichia coli O157:H7 is a predominant serotype of Shiga toxin producing E. coli (STEC) and is responsible for many outbreaks worldwide. Until recently, there is no comparative study on the bovine and clinical isolates as no STEC O157:H7 has been isolated from patients in Bangladesh. In the present study, the local bovine isolates were compared with a reference clinical strain to investigate whether the bovine isolates are capable of producing same degree of illness as the clinical strain. Two local isolates (CD-11 and CD-17) of bovine origin and a reference clinical strain (E. coli O157:H7 NCTC 12079) were investigated for the presence of virulence genes by polymerase chain reaction (PCR), Shiga toxin production by VTEC-RPLA, invasive property by Congo red binding and Sereny’s keratoconjunctivitis, and other enterotoxic, cytotoxic and mouse lethal activities. Both the local isolates and the reference clinical strain showed the presence of eae and stx2 genes and were found to be ...
The object of the present work is to establish a foundation for the design and manufacturing of c... more The object of the present work is to establish a foundation for the design and manufacturing of composite materials for combined mechanical, thermal, and electrical applied conditions. The present paper will discuss a new non-invasive interrogation method for establishing not only internal integrity but also the nature and distribution of internal material structure and defect morphology changes by applying broadband dielectric spectroscopy to detect conductivity and permittivity changes during the history of loading. Interpretations of the results by analysis of discrete local details, and by the introduction of a generalized compliance method will be presented. Prognosis methods based on the technique will also be discussed. Data and examples of application of the method for woven glass reinforced polymer matrix materials will be presented. Opportunities for application of the method to design for durability in multi-physics applications will be identified.
The present paper is concerned with heterogeneous materials in which the mor-phology is specifica... more The present paper is concerned with heterogeneous materials in which the mor-phology is specifically designed to achieve functional properties. These materials, or mate-rial systems, are found in energy systems such as fuel cells and batteries, but also in aeronau-tical structures such as the conductive skins of commercial airplanes which have polymer composite primary structures. Many of these heterogeneous materials are dielectric and, under certain conditions, conductive. Charge transport and storage in such materials is typi-cally discussed in terms of equivalent (electrical) circuits, without recourse to first principles physics or mechanics. The present paper discusses the transport and storage properties of several examples of such materials from a computational standpoint, and compares some critical predictions with experimental data. Opportunities and needs for improving our un-derstandings and computational capabilities for this class of problems will also be discussed.
2011 International Conference on Electronic Devices, Systems and Applications (ICEDSA), 2011
This paper presents a modified Valley-Fill (VF) ballast circuit to combine with a current fed res... more This paper presents a modified Valley-Fill (VF) ballast circuit to combine with a current fed resonant inverter as the power circuit for a high power factor VF electronic ballast. The original VF circuit permit input current conduction from 30 o to 150 o , and then from 210 o to 330 o . Due to this discontinuity, high total harmonic
ASME 2010 8th International Fuel Cell Science, Engineering and Technology Conference: Volume 2, 2010
ABSTRACT In the present work, we are concerned with heterogeneous material systems that have mult... more ABSTRACT In the present work, we are concerned with heterogeneous material systems that have multiple distinct materials and void phases, and associated interfaces, for which the geometric scale and specific morphology at the micro/nano-level play an essential role in the global properties, functional behavior, and material system performance. Such materials are at the heart of revolutionary advances in devices that convert and store energy (e.g., batteries, fuel cells, solar cells, capacitors, and many electro-optical devices), and other membrane-based devices used in chemical and fuel processing, sequestration, and extraction. In recent years, advances in a variety of additive manufacturing methods and techniques have made it possible to design, control, and fabricate specific micro- or nano-structure to achieve prescriptive functional performance of the material systems and devices in which they appear. However, systematic multiphysics analysis methods properly set on field equations that represent the local details is not available, so that first-principles understandings and designs of those materials are not properly founded. Recently, the doe established an energy frontiers research center for physics based nanostructure design and fabrication of hetero geneous f unctional m aterials, called the HeteroFoaM center, to address this and related questions. The present paper presents some initial findings of part of that effort related specifically to morphology. For the present study, a finite element model (FEM) was developed Using COMSOL MULTIPHYSICS to predict impedance behavior when the field equations are set on the local features of regular geometric micro-structures The results for are compared with experimental data obtained from impedance spectroscopy of single SOFC fuel cell elements. For the model, equivalent idealized geometric structures were assumed corresponding to the YSZ material morphology of the fuel cell. Continuously aligned pore structures were represented by rectangular extrusions and regular porosity was represented by geometric shapes such as circles, rectangles and triangles. For experimental data, fragments of a button cell were used with silver paste contacts on the electrodes. For the model, the geometric microstructure was varied by using different shapes i.e. circles, rectangles and triangles while keeping the total material quantity constant, and by using equivalent areas for each of the geometric shapes. Impedance response for the frequency range from 1Hz to 1MHz was obtained for both the models and the experiments. Observations and interpretations of morphology effects are presented.
Abstract. We present the NOVA Workflow tool-suite, a prototype for a process, information and com... more Abstract. We present the NOVA Workflow tool-suite, a prototype for a process, information and communication management tool to guide and inform real world workflows with special attention to the needs of health services delivery. NOVA Workflow is an innovative ...
Page 120. Model checking workflow monitors and its application to a pain management process Fazle... more Page 120. Model checking workflow monitors and its application to a pain management process Fazle Rabbi, Ahmed Shah Mashiyat, and Wendy MacCaull Centre for Logic and Information St. Francis Xavier University {rfazle, x2008ooc, wmaccaul}@ stfx. ca Abstract. ...
Over the years, researchers have investigated how to provide better support for hospital administ... more Over the years, researchers have investigated how to provide better support for hospital administration, therapy and laboratory workflows. Among these efforts, as with any other safety critical system, reliability of the workflows is a key issue. In this paper, we provide a ...
Uploads
Papers