Some Studies In The Disintegration Of Laminar Liquid Jets In Immiscible Binary Liquid Systems

The breakup of a liquid jet in an immiscible liquid has been investigated. The variation in the jet break-up length was studied to determine the influence of various parameters e.g. amplitude and frequency of the applied vibrations. To generate experimental data a rig was designed and constructed. To maintain a constant flow of the dispersed phase through the nozzle, a number of techniques were tried. A compressed air system was found to be the most suitable to develop a constant head for the flow and no variation in the flow of a dispersed phase was observed after 12 hours. Initially experiments were conducted at a high flow rate of the dispersed phase and the variation in the jet length was measured under the influence of externally applied vibrations. It was found that amplitude and frequency of the applied vibration influenced the jet break-up length. Rayleigh's equation was applied to correlate the experimental data. It was found that the applied frequency does not effect the growth rate but it does influence the jet break-up length. Hence Rayleigh's equation was modified to allow for this variation. The error between experimental and predicted results was found to be not more than the difference in the dropsizes. To eliminate this error, the measurement technique previously employed (still photography) was supplemented with a video technique and the jet length measurements were only taken when monosized droplets were produced. At low flow rates it was found easier to produce monosized droplets, hence subsequent measurements were taken in this flow region. To correlate experimental data Rayleigh's equation was further modified to take into account the influence of a natural and an applied vibration. Theoretical and experimental results agree well within the range of error ± 0.30 mm. It was found that the number of monosized droplets produced were equal to the applied frequency. Any change in the frequency altered the dropsize because the flow rate was constant

Hydrodynamics of drop formation in liquid-liquid systems: investigation and interpretation of drop sizes in liquid-liquid systems as a function of nozzle diameter, nozzle velocity and physical properties of the systems

Drop formation processes from a nozzle of diameter 0.0602 cm in immiscible liquids were investigated experimentally and theoretically. Experimental data for drop sizes in prejetting and jetting regimes were obtained. In the prejetting conditions for water into decane system, data for drop formation time, drop diameter and drop velocities were obtained at three different Weber numbers using still photography and high speed cine film photographic techniques. A model has been developed to account for a two stage drop formation process in the prejetting regime. In the jetting regime three liquid pairs were employed with injection of dispersed phase from above and below the continuous phase to give a range of physical properties. Interfacial tension was varied from 3.1 to 27.5 mNm-1. The ratio of the continuous phase to the dispersed phase densities was varied from 0.73 to 1.36. The ratio of viscosities of the two phases was varied from 0.063 to 15.7. The experimental data for minimum drop size, mean drop size, jetlength and jet diameter were obtained from still photography. Experimental data for wave length, wave period, wave amplitude of the fastest growing disturbance on the jet were obtained by stroboscopic and high speed photographic techniques. A linear stability analysis for small scale hydrodynamics of the wave motion has been developed to predict the wave growth rate in the jetting regime. Patterns of drop formation and drop size variations in the intermediate regime were investigated and a semi-theoretical correlation was obtained to predict the drop size in the intermediate regime

Optimization of multi-gigabit transceivers for high speed data communication links in HEP Experiments

The scheme of the data acquisition (DAQ) architecture in High Energy Physics (HEP) experiments consist of data transport from the front-end electronics (FEE) of the online detectors to the readout units (RU), which perform online processing of the data, and then to the data storage for offline analysis. With major upgrades of the Large Hadron Collider (LHC) experiments at CERN, the data transmission rates in the DAQ systems are expected to reach a few TB/sec within the next few years. These high rates are normally associated with the increase in the high-frequency losses, which lead to distortion in the detected signal and degradation of signal integrity. To address this, we have developed an optimization technique of the multi-gigabit transceiver (MGT) and implemented it on the state-of-the-art 20nm Arria-10 FPGA manufactured by Intel Inc. The setup has been validated for three available high-speed data transmission protocols, namely, GBT, TTC-PON and 10 Gbps Ethernet. The improvement in the signal integrity is gauged by two metrics, the Bit Error Rate (BER) and the Eye Diagram. It is observed that the technique improves the signal integrity and reduces BER. The test results and the improvements in the metrics of signal integrity for different link speeds are presented and discussed

Training & Development Practices in National Bank of Pakistan

The purpose of this study is to explore the training & development practices in National Bank of Pakistan (NBP). Different levels of officers are providing training & development opportunities in NBP. Data collected from different staff colleges of NBP. Result of this study shows, bank is providing training & development opportunities to its employees, but there is still gap which should be addressed. Training need analysis is not sufficient. Most of the trainers belong to operational background and they are unable to provide the sufficient training to develop the good employees. Bank does not have sufficient T&D plan for the top-level management

Optimization of multi-gigabit transceivers for high speed data communication links in HEP Experiments

The scheme of the data acquisition (DAQ) architecture in High Energy Physics (HEP) experiments consist of data transport from the front-end electronics (FEE) of the online detectors to the readout units (RU), which perform online processing of the data, and then to the data storage for offline analysis. With major upgrades of the Large Hadron Collider (LHC) experiments at CERN, the data transmission rates in the DAQ systems are expected to reach a few TB/sec within the next few years. These high rates are normally associated with the increase in the high-frequency losses, which lead to distortion in the detected signal and degradation of signal integrity. To address this, we have developed an optimization technique of the multi-gigabit transceiver (MGT) and implemented it on the state-of-the-art 20nm Arria-10 FPGA manufactured by Intel Inc. The setup has been validated for three available high-speed data transmission protocols, namely, GBT, TTC-PON and 10 Gbps Ethernet. The improvement in the signal integrity is gauged by two metrics, the Bit Error Rate (BER) and the Eye Diagram. It is observed that the technique improves the signal integrity and reduces BER. The test results and the improvements in the metrics of signal integrity for different link speeds are presented and discussed

Characterization of wheat varieties by seed storageprotein electrophoresis

Wheat grains of thirteen varieties were collected from different ecological regions of Pakistan. The variability of seed storage-proteins was analyzed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Electrophorogram for each variety were scored and Jaccard‘s similarity index (JSI) was calculated. Genetic diversity of wheat was evaluated by constructing the dendrogram for high molecular weight (HMW) and low molecular weight (LMW) gluten subunit bands. It is concludedthat seed storage protein profiles could be useful markers in the studies of genetic diversity and classification of adapted cultivars, thereby improving the efficiency of wheat breeding programs in cultivar development especially in a developing country like Pakistan

Test and characterization of a prototype silicon-tungsten electromagnetic calorimeter

New generation high-energy physics experiments demand high precision tracking and accurate measurements of a large number of particles produced in the collisions of lementary particles and heavy-ions. Silicon-tungsten (Si-W) calorimeters provide the most viable technological option to meet the requirements of particle detection in high multiplicity environments. We report a novel Si-W calorimeter design, which is optimized for $\gamma/\pi^0$ discrimination up to high momenta. In order to test the feasibility of the calorimeter, a prototype mini-tower was constructed using silicon pad detector arrays and tungsten layers. The performance of the mini-tower was tested using pion and electron beams at the CERN Proton Synchrotron (PS). The experimental results are compared with the results from a detailed GEANT-4 simulation. A linear relationship between the observed energy deposition and simulated response of the mini-tower has been obtained, in line with our expectations.Comment: 13 figures, represents test beam data with PS beam line at CER

Trigger and Timing Distributions using the TTC-PON and GBT Bridge Connection in ALICE for the LHC Run 3 Upgrade

The ALICE experiment at CERN is preparing for a major upgrade for the third phase of data taking run (Run 3), when the high luminosity phase of the Large Hadron Collider (LHC) starts. The increase in the beam luminosity will result in high interaction rate causing the data acquisition rate to exceed 3 TB/sec. In order to acquire data for all the events and to handle the increased data rate, a transition in the readout electronics architecture from the triggered to the trigger-less acquisition mode is required. In this new architecture, a dedicated electronics block called the Common Readout Unit (CRU) is defined to act as a nodal communication point for detector data aggregation and as a distribution point for timing, trigger and control (TTC) information. TTC information in the upgraded triggerless readout architecture uses two asynchronous high-speed serial links connections: the TTC-PON and the GBT. We have carried out a study to evaluate the quality of the embedded timing signals forwarded by the CRU to the connected electronics using the TTC-PON and GBT bridge connection. We have used four performance metrics to characterize the communication bridge: (a)the latency added by the firmware logic, (b)the jitter cleaning effect of the PLL on the timing signal, (c)BER analysis for quantitative measurement of signal quality, and (d)the effect of optical transceivers parameter settings on the signal strength. Reliability study of the bridge connection in maintaining the phase consistency of timing signals is conducted by performing multiple iterations of power on/off cycle, firmware upgrade and reset assertion/de-assertion cycle (PFR cycle). The test results are presented and discussed concerning the performance of the TTC-PON and GBT bridge communication chain using the CRU prototype and its compliance with the ALICE timing requirements