SET based experiments for HTSC materials: II

The cuprates seem to exhibit statistics, dimensionality and phase transitions in novel ways. The nature of excitations [i.e. quasiparticle or collective], spin-charge separation, stripes [static and dynamics], inhomogeneities, psuedogap, effect of impurity dopings [e.g. Zn, Ni] and any other phenomenon in these materials must be consistently understood. In this note we further discuss our original suggestion of using Single Electron Tunneling Transistor [SET] based experiments to understand the role of charge dynamics in these systems. Assuming that SET operates as an efficient charge detection system we can expect to understand the underlying physics of charge transport and charge fluctuations in these materials for a range of doping. Experiments such as these can be classed in a general sense as mesoscopic and nano characterization of cuprates and related materials. In principle such experiments can show if electron is fractionalized in cuprates as indicated by ARPES data. In contrast to flux trapping experiments SET based experiments are more direct in providing evidence about spin-charge separation. In addition a detailed picture of nano charge dynamics in cuprates may be obtained.Comment: 10 pages revtex plus four figures; ICMAT 2001 Conference Symposium P: P10-0

INTERNAL FACTORS, EXTERNAL FACTORS AND BANK PROFITABILITY

A developed banking sector provides the impetus for the economy to grow. However, in order to maintain financial stability and sustain negative shocks, it is important to understand the factors that influence the profitability of banks. The aim of the study was to analyse the effect of internal and external factors on the profitability of banks in Pakistan for the period 2007-2015. Fixed effects model was used to analyse the effect of internal and external factors on the profitability of banks in Pakistan. The findings of the study revealed that among internal factors only bank size and asset composition significantly influences the profitability of banks whereas in the external determinants only real interest rates and GDP growth rates has a significant effect on the profitability of banks

Threaded spikes for bluff body base flow control

Although the demand for rockets and missiles has increased exponentially the problems of the gas dynamics related to these vehicles remains to be a challenge. The main problem is high-pressure associated with the shock wave in front and low-pressure recirculation bubble attached behind the vehicle at the blunt base. This barrier of wave drag due to the shock waves and the drag due to the bubble leads to a huge amount of the fuel consumption and high fluctuations in the flow field of the enlarged duct. This paper focuses mainly on the base drag and experimentally investigated the effect of the passive control in the form of the threaded spikes for bluff bodies as the base flow controller. Two threaded spikes of length 40 mm opposite to each other and attached to a control plate of diameter 80 mm and thickness 1 mm is at pitch circle diameter of 23 mm and slot of 10 mm X 10 mm at the center, placed between the nozzle and the duct to act as the passive controller. The Mach numbers considered for the investigation in the subsonic regime were 0.6, 0.7 and in the transonic regime were 0.8, 0.9 for the enlarged duct cross-sectional area of 625 mm 2 and the exit area of the nozzle considered were 100 mm2. The lengths of the enlarged duct were 100 mm, 150 mm and 200 mm. The passive control and regulating the base pressure by threaded spikes were found very efficient without any adverse effect on the flow field of the enlarged duct

Numerical investigation of critical range for the occurrence of secondary peaks in the Nusselt distribution curve

The study of heat transfer augmentation in micro/nano scale and electronic packaging systems are some of the paramount areas of impending universe. In such systems the cooling of the hot heat sinks is generally achieved through the impingement of air jet. In order to study the characteristic of heat dissipation rate, variation of Nusselt number versus radial distance over the target surface is investigated. The magnitude of Nusselt Number is found to decrease gradually with increase in the radial distance away from the jet. The record of Nusselt magnitude over the radial distance is accomplished through computation using ANSYS CFX 14.5. A 2-D axis-symmetric model consisting of nozzle and target surface with discrete meshing is solved using an appropriate turbulence model, in order to develop the flow regime and record the necessary heat interactions. As far as the transition and intermediacy in flow structure at the target surface due to the un-predicted transport of shear stress is concerned, SST along with Gamma – Theta turbulence model is solved simultaneously in order to incorporate these phenomena.. The occurrence of such secondary peaks increases the heat transfer rate. Looking into the light of research area in determining the exact cause and the intervening range for the occurrence of such peaks, the current research focuses over the determination of the critical range within which the secondary peaks exists. This critical range comprises of multiple of jet to the target spacing and diameter-based Reynolds number and the corresponding critical range is between 2205 and 26, 46, 000. Not only that the velocity contour of the flow regime is mapped for the sets of parameters within the critical range. An empirical correlation for the area averaged Nusselt number terms of Reynolds number and jet to the target spacing being is proposed. This correlation improvises the calculation of the magnitude of area