Many Topological Insulators Fail the Surface Conduction Test

In this report, we scrutinize the thickness dependent resistivity data from the recent literature on electrical transport measurements in topological insulators. A linear increase in resistivity with increase in thickness is expected in the case of these materials since they have an insulating bulk and conducting surface. However, such a trend is not seen in the resistivity versus thickness data for all the cases examined, except for some samples, where it holds for a narrow range of thickness.Comment: 11 pages, 3 figure

Universal Properties of Linear Magnetoresistance in Strongly Disordered Semiconductors

Linear magnetoresistance occurs in semiconductors as a consequence of strong electrical disorder and is characterized by nonsaturating magnetoresistance that is proportional to the applied magnetic field. By investigating a disordered MnAs-GaAs composite material, it is found that the magnitude of the linear magnetoresistance (LMR) is numerically equal to the carrier mobility over a wide range and is independent of carrier density. This behavior is complementary to the Hall effect that is independent of the mobility and dependent on the carrier density. Moreover, the LMR appears to be insensitive to the details of the disorder and points to a universal explanation of classical LMR that can be applied to other material systems.Comment: Accepted by Phys. Rev. B (2010

STUDY OF BINDING INTERACTIONS OF HUMAN CARBONIC ANHYDRASE XII

Objective: The present study was carried out to study the binding interactions of different N'-(substituted phenyl sulfonyl)-pyridine-2-carbohydrazide derivatives and N'-(substituted phenyl sulfonyl)-thiophene-2-carbohydrazide derivatives which were synthesized by senior students from research laboratory, with objective to explore the suitability of selected ligands for their binding affinity for the selected target.Methods: Binding interactions of the selected ligands were studied using glide module of Schrodinger software using Maestro 10.1 interface. At the end of molecular docking studies, docking scores along with 2D and 3D binding interactions of these ligands were studied to evaluate the potency of ligands to act as selective human carbonic anhydrase (hCAXII) inhibitors in comparison with standard inhibitor Acetazolamide (AZA).Results: Docking study on the ligands exhibited very similar conformation and binding interactions with hCAXII as that of standard. This suggests that selected ligands might possess significant binding affinity for hCAXII.Conclusion: It can be concluded that the selected ligands have the potential to act as inhibitors of hCAXII

Effect of Fluid Suction on an Oscillatory MHD Channel Flow with Heat Transfer

Magnetohydrodynamics (MHD) is generally concerned with the study of the magnetic properties (behaviour) of electrically conducting fluids (plasmas, liquid metals etc.) moving in an electromagnetic field. The importance of the concept of MHD in various fields such as astrophysics, bio-medical research, missile technology and geophysics motivates the modelling and investigation of MHD flow and transport problems. The role of fluid suction is paramount in laminar flow control and has wide applications in fields such as aeronautical engineering, automobile engineering and rocket science. This fact inspires the study of the effects of fluid suction in flow and transport models. Time dependent flows are widely encountered in engineering applications such as turbines and in physiological studies such as flow of bio-fluid (blood etc.). In the present paper, an attempt has been made to investigate analytically the problem of a time dependent channel flow with heat transfer, where the channel is bounded by two infinite parallel porous walls. The pressure gradient is assumed to be oscillatory in nature. A magnetic field of uniform strength is assumed to be applied normal to the walls. After necessary idealization of the momentum and energy equations, the governing equations of our problem are solved by adopting the regular perturbation technique. The effects of magnetic field, suction velocity, viscous dissipation, Reynolds number, Prandtl number etc. on the flow and heat transfer are studied and demonstrated graphically. It is seen that magnetic field, fluid suction, viscous dissipation, Reynolds number, Prandtl number have a significant effect on the flow and heat transfer characteristic. For instance, the imposition of the magnetic field enhances the rates of heat transfer at the walls and the fluid suction decreases the temperature and aids in laminar flow control

Non-formal education and grassroots development : a case study from rural Bangladesh

Through the case study of Gono Unnayan Prochesta (GUP), Voluntary Organization (VO) operating in rural southwestern Bangladesh, this thesis explores the role of non-formal education for empowerment and socio-economic development. The issues examined are the mobilization process and the grassroots organization of disadvantaged women, education for regenerative agriculture, functional literacy and women's health. The case study focuses mainly on two womens groups. During the field work part of the study, most men were away from the villages in pursuit of salaried jobs or carrying out their small trades. The study adopted the framework of analysis proposed by Moser (1993) about the productive, reproductive and community roles of women in the context of their practical and strategic needs. The data indicates that due to the extreme poverty situation in the study area, addressing practical needs is considered more urgent by the women who were interviewed. Furthermore, they indicated that the center-based functional literacy training is less effective than the home-based training related to health and agriculture issues. It also was observed that the gosthi (lineage) shanskriti (cultural) and para (neighborhood) identities are essential elements in mobilizing the women's groups in the villages. After 25 years of GUP's activities, grassroots women's organizations are yet to be self-sustaining in the villages of Rajoir. The women participants in this study understand the importance of learning how to sign their names for access to small loans, although they indicate that further functional literacy does not meet their immediate practical needs. They are aware of the value of literacy and formal education for their children. Even then, the immediate projects they finance with small credits and loans available to them are still distributed alone traditional gender roles; seed money for starting small businesses for their sons or dowry needs

Macro with Pico Cells (HetNets) System Behavior Using Well-known scheduling Algorithms

This paper demonstrates the concept of using Heterogeneous networks (HetNets) to improve Long Term Evolution (LTE) system by introducing the LTE Advance (LTE-A). The type of HetNets that has been chosen for this study is Macro with Pico cells. Comparing the system performance with and without Pico cells has clearly illustrated using three well-known scheduling algorithms (Proportional Fair PF, Maximum Largest Weighted Delay First MLWDF and Exponential/Proportional Fair EXP/PF). The system is judged based on throughput, Packet Loss Ratio PLR, delay and fairness.A simulation platform called LTE-Sim has been used to collect the data and produce the paper outcomes and graphs. The results prove that adding Pico cells enhances the overall system performance. From the simulation outcomes, the overall system performance is as follows: throughput is duplicated or tripled based on the number of users, the PLR is almost quartered, the delay is nearly reduced ten times (PF case) and changed to be a half (MLWDF/EXP cases), and the fairness stays closer to value of 1. It is considered an efficient and cost effective way to increase the throughput, coverage and reduce the latency