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Mathematical modeling and analysis of ciliary induced flow of Newtonian and non-Newtonian fluids
No full textThe present thesis deals with a mathematical study of ciliary induced flows of various nonNewtonian fluids through a planar channel and in an axially symmetric tube. The main motivation of the present research work is concerned with an investigation of the propulsion mechanics of ciliary induced flows of some biological fluids through certain physiological systems of the human body. In particular, we want to study the role.of ciliary movement in the transport of spermatic fluids through the ductuli efferentes of male reproduction system in the human beings through mathematical modeling. The spermatic fluids or the efferent duct materials are assumed as Casson, Carreau, micropolar, hydromagnetic conducting Newtonian fluids and the geometry of the ductus efferentes of the human male reproduction system is approximated with a planar channel of uniform dimensions and an axially symmetric uniform cylinderical tube. The mathematical equations governing the flow of the present problem are formulated in Cartesian and axisymmetric cylindrical coordinate systems. These are highly nonlinear and coupled partial differential equations. However, implication of the well known creeping flow approximation along with the long wavelength assumption permits us to obtain closed form exact solutions for the resulting simplifying system of equations governing the flow problems. This is a valid approach for the low Reynolds number flows and is widely used in the literature of physiological dynamics. The flow is produced under the action of ciliary beating that generates a metachronal wave and the analysis is made in the wave frame travelling at the speed of metachronal wave in the direction of flow. Exact solutions for velocity components, axial. pressure.gradient and the stream. function are obtained. For Carreau fluid model the governing system of equations is.reduced to a.system of nonlinear but ordinary differential equations by employing the creeping flow i.e., the low Reynolds number assumption along with the long wavelength approximation. In this case, we utilize the well known regular perturbation method to tackle the nonlinear.terms of the governing system of equations. Consequently, series form solutions for the stream.function, the velocity.distributions and the pressure.gradient are computed. In last two chapters, we have investigated the magnetohydrodynamics (MHD) effects on the ciliary induced flows by assuming that the efferent duct material is a conducting fluid. The applications of magnetohydrodynamics principles in physiological-type flows have been the subject of intensive research and study during the last few years. The study of MHD effects on the flow of spermatic fluids through the ductus efferents is a relatively new aspect of the problem. We have studied the problem theoretically through a mathematical model. The quantities of physical interest like the pumping characteristics, the ciliary trapping phenomenon, the axial pressure gradient, the velocity distribution and the volume flow rates are discussed in this study. Extensive analytical and numerical computations are carried out to obtain the results of various flow characteristics of physiological interest. The influence of pertinent parameters on the analytical results obtained by these models are analyzed and discussed through graphs. The numerical values of the volumetric flow rate obtained by the proposed models of our study are \ud
also compared with the experimentally estimated value of the flow rate of the human semen, 3 6 10 mlh ?? . This estimated value was suggested by Lardner and Shack [1] in human based on the flow rates in the ductus efferentes in the other animals, e.g., rat, ram and bull. These values are found to be in excellent agreement with the estimated value as compared to the value obtained by the Newtonian model of Lardner and Shack which was 3 1 0.12 10 mlh ? ??
Impact of Mergers and Acquisitions on Operating Performance of Firms: Evidence from Pakistan
No full textThis dissertation is a study on the objectives of mergers and acquisitions as to \ud
why organizations undertake the inorganic mode of expansion. To conduct a uniform \ud
research and arrive at an accurate conclusion this study is restricted to only Pakistani \ud
companies. To get broader perspective on Pakistan this study is divided into two main \ud
sectors of Pakistani economy namely manufacturing and financial sector. This research \ud
study is conducted to find the impact of mergers and acquisitions on operating \ud
performance of acquiring firms in different industries by examining pre-merger and post\ud
merger financial ratios, with a sample of firms chosen from all mergers involving public \ud
limited and traded companies belonging to manufacturing and financial sector. In this \ud
study the impact of merger and acquisition on profitability, efficiency, liquidity, leverage, and capital performance variables is measured by using statistical and econometrics \ud
techniques such as paired sample t-statistics, data envelopment analysis (DEA) and panel \ud
regression analysis. Sample of this research consists of thirty-two manufacturing and \ud
twenty non-manufacturing companies involved in the process of merger and acquisition during 1998-2012.Sample firms are selected from Karachi stock exchange (KSE) and Lahore stock exchange (LSE). It is a secondary data based research. Three years pre and post-merger data is used to test the significance of study. Paired sample t-test statistics is applied on accounting ratios with the help of statistical software SPSS. In this study fixed effect panel data regression is used to test the impact of mergers and acquisitions on the operating performance of companies. The result of this study shows that Pakistani companies are no different than the companies in other parts of the world. On the basis of findings it is concluded that overall operating performance of acquiring manufacturing, modaraba companies, insurance corporations, investment banks and mutual funds corporations significantly improved in the post- post-merger period. On the other hand findings also reveal that post-merger performance of banks improves and leasing sector insignificantly deteriorated
Effect of Crack on Structural Dynamics and Aeroelastic Analysis of Structures
No full textField of Structural dynamics and Aeroelastic analysis is getting day by day strength due to change in materials like new alloys (Isotropic) and composites (Anisotropic). Aerospace industry is using both materials and due to defects like cracks and holes during field operation are difficult to avoid hence facing catastrophic failures. In previous published researches, cracks ,holes and symmetric / Asymmetric masses were analyzed separately but their cumulative affect were never analyzed for the real aerospace structures both isotropic and anisotropic materials/ structures. In this dissertation, by considering both isotropic and Anisotropic structures ,theoretical and experimental studies were conducted for five different cases i,e no crack, Cracks, cracks and holes, cracks, holes and symmetric masses and crack, holes and Asymmetric masses for the evaluation of their cumulative effect on structural dynamics and aeroelastic analysis. Isotropic structure considered was steel plate and anisotropic material was considered newly designed /manufactured composite model test wing. In this research, an analytical cum experimental methodology was introduced in order to reduce the catastrophic failures of aerospace structure both isotropic and anisotropic in future to save the time , money and to predict the more accurate new flutter speed of damage aerospace structures along with lumped masses. In linear elastic structural dynamics analysis, change in first four eigenvalues and eigenvectors were observed due to the five cases in term of shift in frequencies. Another important parameter, delta (difference in first bending and first torsion) was also observed both numerically and experimentally through modal analysis in steel plate and composite model test wing. Numerical simulation was performed using FEM in MSC Nastran. Experimental work was performed using experimental modal analysis; Ground Vibration Testing (GVT). Numerical simulation and experimental results showed good agreement.Numerical Aeroelastic analysis was performed on both steel plate and newly designed composite model test wing for five cases. Both the structures were modeled for subsonic flows according to potential flow theory. The potential flow is governed by the aerodynamic potential equation, a linear partial differential equation. The aerodynamic potential equation is solved using a distribution of doublets that relates pressure to downwash in the doublet lattice method (DLM). The aeroelastic model couples the structural and aerodynamic models using Lagrange's equations. The flutter boundary is predicted using the P-K method by plotting Velocity-Frequency (V-f) and VelocityDamping (V-g) curves. Instead of performing experimental flutter analysis or wind tunnel testing, a Mathematical Aeroelastic Analysis Tool (MA'AT-1) was developed which was validated against AGARD 445.6 in terms of DLM and PK method in which bending and torsional stiffness were experimentally determined and finally flutter speed for all five cases was calculated. Results are showing close agreement for flutter speeds obtained from MA'AT-1 and numerical performed aeroelastic analysis in MSC Nastran. In this research, to make the use of Mathematical Aeroelastic Analysis Tool (MA'AT-1), friendly and easy, a Graphical User Interface (GUI) is developed in MATLAB. This GUI is based on proposed new methodology by using MA'AT-1 to predict the new flutter speed of aerospace structure before and after the structural defects along with and without lumped masses. Proposed new methodology will reduce catastrophic failures of aerospace structures in future by redefining the flutter flight envelope, which is biggest challenge to aircraft manufacturing industry
MODELING AND CONTROL FOR TRAJECTORY TRACKINGANDMULTI-ROBOT FORMATION OF NONHOLONOMIC WHEELED MOBILE ROBOTS
No full textWheeled mobile robots (WMRs) are difficult to stabilize and control due to nonholonomic constraints. The complexity of control increases when there is a need to control a group of WMRs in a specific formation. The research described in the thesis concerns the modeling, controlandformationofnonholonomicWMRsfortrajectorytracking.</BR> Inparticular,thisresearchworkproposesnovelcontrolapproachesforWMRtrajectorytrackingandformation control of multi-robot system. The kinematic model of WMR is studied, and then various kinematic controllers have been implemented to identify suitable kinematic controller for WMR trajectory tracking using performance based simulation results. The trajectory tracking problem is extended by including the dynamic model of WMR along with the model uncertainties and disturbances. A novel adaptive sliding mode state feedback control law is proposed for trajectory tracking, which includes the integral action and hence it is able to remove the steady state errors and reject the external disturbances. The proposed adaptive dynamic controller uses velocities as input commands, which is more practical and appropriate from the view-point of real-time application. The proposed dynamic state feedback controllerrequiresallthestatesspeciallyWMRlinearandangularvelocities. Therefore,the trajectorytrackingcontrolproblemisaddressedagaininthecontextofoutputfeedbackcontrol for WMR. The tracking formulation is defined with the high gain observer to estimate the linear and angular velocities. It is shown that using high gain observer and a globally bounded state feedback stabilizing controller, the close-loop system performance can be recovered in the presence of un-modeled dynamics. The formation control problem of\ud
multi-robot system is addressed using leader-follower formation approach. The kinematic modeloftheleader-followerformationisdevelopedinthepresenceofuncertaintiesanddisturbances. It is followed by an integral terminal sliding mode control for robust formation control and finite-time convergence. The proposed controller eliminates the requirement of leader's velocity information which increases the reliability of multi-robot system. Obstacle detection and collision avoidance are incorporated to maintain the desired formation in the presence of obstacles. The stability analyses is carried out using Lyapunov stability theory. The performances are verified and validated using time invariant and time varying trajectories
Discovery of Novel Bioactive Secondary Metabolites from Seriphidium Quettense, Vincetoxicum Stocksii and an Endophytic Fungus Cryptosporiopsis Sp.
No full textN/
PHARMACOTHERAPUTIC STUDIES AND ASSOCIATED RISK FACTORS OF BREAST CARCINOMA IN LOCAL POPULATION
No full textBreast cancer has emerged as a major devastating disease for females globally. Trends in the incidence of breast cancer differ worldwide due to various factors like cultural, environmental, life-style factors, etc., hence distinct study for every geographical zone is necessary. Many researches have been done to probe information regarding its major risk factors so that improvements can be made not only regarding its screening procedures but also for its pharmacotherapy/ management. The objectives of this research were: to determine the association of selected characteristics in the cases and controls regarding breast cancer; to determine the risk of breast cancer incidence in females associated with various factors; to evaluate the use and response of various therapies employed in breast cancer cases; to assess the adverse effects occurring after the use of various therapies in breast cancer cases. \ud
This thesis is a descriptive study that covers both epidemiological and medical features of breast cancer in Pakistani females and is presented with application of statistical methods and international assessment scales. The research work was conducted in KIRAN hospital recruiting n=811 breast cancer cases and n=1965 controls were recruited from all over Karachi. Majority respondents lied in the age group of 31-50 years (p<0.05) and were married. There were significant variations in the education level of both the cases and controls (p<0.001). Many of the life style and reproductive characteristics of the respondents were associated significantly (p<0.001). A strong, positive family history of breast cancer was found only in a very few cases and not in the control group. The results of logistic regression analyses, stratification by tumor receptor status and menopausal status showed that the odds of attaining breast cancer in the cases were likely to be associated with marriage within family, in housewives, low education level, milk consumption, menarche age > 13 years, in menopausal women, no breast feeding, family history of breast cancer and concomitant diseases like hypertension and diabetes mellitus. \ud
Breast cancer stage 1 was found prevalent with cases of left side; most of the patients were suffering from breast cancer belonged to the age group of 31-50 years. Fortunately, breast cancer metastasis was seen in a very few cases (n=101) which mostly involved bones (38.46%) and \ud
lungs (33.33%). Among n=811 cases, mostly were ER +ve, PR -ve and HER 2 Neu -ve. The joint receptor status showed that there were 39.4% E/P+H-, 25.70% E/P+H+, 13.70% E-P-H+ and 36.16% E-P-H- breast cancer cases. \ud
Different treatment modalities were employed for breast cancer cases and various treatments involved local therapy (surgery and radiation), chemotherapy and endocrine therapy. Among all the cases, 95.68% underwent surgery, majority belonging to the age group of 31-50 years. Radiation therapy was employed for 97.16% cases. The overall response for radiation therapy was 'good' (complete) in >90% cases showing statistically significant association in the age groups of 31-40 (p<0.05) and >51 (p<0.001) years. The adjuvant endocrine therapies were prescribed to n=508 cases, in which Tamoxifen (20 mg tablets) were prescribed to 96.06% cases. The cases receiving endocrine therapy were mainly ER +ve (47.24%), PR -ve (53.7%) and HER 2 Neu -ve (45.3%); general response perceived was 'good' (complete) in the cases. Chemotherapy was prescribed to n=760 cases, majority belonging to the age group of 41-50 years. Its response was found 'good' (complete) significantly (p<0.001) in the age groups of 2030 years and 41-50 years. \ud
The ADRs occurring due to breast cancer treatments were assessed and also analyzed by using 3 different international scales for causality, preventability and severity i.e. Naranjo's algorithm, modified Schumock and Thornton scale and modified Hartwig's and Siegel scale respectively. The most common adverse effects observed in breast cancer cases due to radiation therapy were fatigue/ body aches (>75%) and skin hyperpigmentation (>70%). The most commonly found ADRs related to adjuvant endocrine therapy were heat intolerance (50.98%) and myalgia (40.55%). Most commonly occurring adverse events due to chemotherapy were vomiting/ nausea (98.52%), anemia/ neutropenia (94.20%), alopecia (94.08%) and fatigue/anorexia (91.61%). \ud
The present study supports for the association of many characteristics that are potential risk for developing breast cancer in female population in Karachi, Pakistan. The receptor status, cancer grade, environmental, reproductive and life style factors and family history of diseases in the breast cancer cases provide a deep insight to the incidence of breast cancer. The results regarding the use of common treatment modalities in breast cancer cases can aid in designing better and \ud
newer treatment regimens while considering association of individual's specific characteristics. This may also aid in patient education, awareness and counseling to improve compliance; patients can be facilitated with age-appropriate support and care. It was noted that adjuvant biologic therapy besides adjuvant endocrine therapy was not prescribed to patients, which would have been helpful to eradicate the disease
Poverty Alleviation through Communication, Poverty Gap Index and Poverty Triggers With special reference to a Welfare State
No full textThis study investigates the question of poverty alleviation through \ud
communication, poverty gap index and poverty triggers with special reference to a \ud
welfare state. It carries reasons, impact and poverty alleviation programmes by different \ud
international leading organisations namely the World Bank, ADB, IMF and different \ud
international funding and charity organisations and countries having annual grants and \ud
allocations for different programmes aimed at poverty reduction. In Pakistan the \ud
government strategy papers and poverty alleviation, poverty alleviation fund of \ud
Pakistan, provincial governments efforts and plans for reduction in poverty are the \ud
issues referred to in the study. The empirical view has always been there causing \ud
poverty incidents to be examined in the background of income support and poverty \ud
while the question of poverty has to be seen keeping in view the gross national \ud
income/gross domestic product, management by the government, increase in per capita \ud
income and the use of purchasing power poverty and not the simple head count ration \ud
in examining the question of poverty. \ud
There are contradictory reports on poverty estimates. It vary from 25 per cent to \ud
over 50 per cent in Pakistan while the World Bank estimates say that the world \ud
population has the highest number of poor people living in South Asia alone besides \ud
many other regions in Africa and Caribbean, South Asia and South East Asia, West Asia \ud
and in South America where absolute to moderate poverty prevails. \ud
The welfare measurement has also been referred to in this study to measure this \ud
element generally used as poverty gap index for this measurement. Absolute to relative \ud
poverty lines, gini index of income inequality, underlying definitions and concept, all \ud
relevant concepts and triggers are discussed in this thesis in order to have the \ud
understanding about the macro-economic reasons, indicators and poor governance \ud
related to poverty incidence. Any higher growth projection and higher wastes being \ud
contradictory to each other have been never helpful to address the burning issue of any \ud
developing country. Pakistan is a classical case for poverty study where there is not only \ud
mismanagement by provincial governments, poor governance and corruption has been \ud
even known internationally when the Global Corruption Report was released by world\ud
known organisation the Transparency International Germany. \ud
There have been no tangible efforts to use non-economic triggers to control \ud
poverty spread. Communication is one of such triggers that are used in the study helps \ud
manage the attitude and behaviour and properly educate the people through media \ud
usage on economic and social development, investment and habits of savings and \ud
thriftiness. \ud
Of late the introduction of Millennium Development Goals on poverty, health, education and population, governance etc are evident from the fact that the UNDP and its members are serious to address the basic issue of the current century. This has so far not been able to achieve and the minimum 50 % reduction has been revised with another 15 years or so for all the member countries. Only China has been able to address the minimum target of 50 per cent even much earlier than the prescribed time frame
Error Tolerant Video Streaming in IEEE WLAN
No full textBroadband network proliferation at higher bit rates has spurred a host of multimedia streaming applications like internet video surveillance, live broadcast of international events, distant learning and entertainment etc. Wireless networks have been recognized as the most popular networking technology due to their flexible infrastructure, portability and easy deployment. Today's wireless internet user is truly global and can access content free of space or time constraints. But the caveat is that efficient streaming of multimedia contents over wireless links has proven to be an open research problem. In-time packet delivery and successful play out on receiver end are stringent quality requirements of any bandwidth intense, delay-sensitive real time multi-media application. However, wireless link characterized by fluctuating channel bandwidth and route obstacles results in transmitted signal attenuations or loss thus adversely affect the played back video quality. \ud
Ultimately, efficient streaming of multimedia contents over error prone wireless links has emerged as one of the most challenging problems of the current era of digital communication. However, applying unequal error protection strategies and avoiding unnecessary packet discard at various network levels yield valuable outcomes. In this research work, an error control mechanism has been proposed that enables a multimedia application to adapt the video bit rate gracefully with changing channel conditions based on intelligent network estimation. Intelligent link estimation triggers the rate adaptation on sender side through reducing the video bit rate by re-encoding at lower quantization scale. In addition, an error frame forwarding approach based on the idea of discriminating video streaming calls from the data packeting over IEEE WLAN channels through bit demarcation in network packet headers. Error computation at various network levels are evaluated and disabled in order to attain efficient utilization of channel data rates characterized by minimized re-transmissions and reduced delays with least error checksum computations and packet re-transmissions, increased throughput characterized by the higher number of packets available for decoding and enhanced multimedia visual quality due to gap elimination (appears as a consequence of some frame loss).\ud
Results have been supported through experimentation involving numerous video statistics as well as tools and techniques that can possibly be deployed in standard video codecs. Objective and Subjective quality assessments have yielded the encouraging outcomes for a mix of standard video clips (foreman, mother daughter, tennis) with variable mobility level (degree of variations in background and foreground frame contents). Reconstructed video assessment has further been improved through deploying perceptual quality tool with a rich set of parameters available for precise and complete QoE based video analysis. It has been observed that proposed error control strategy has outperformed the traditional error elimination techniques(particularly Automatic Repeat reQuest (ARQ)) for all Group Of Picture (GOP) structures of standard video codecs in terms of efficient utilization of available WLAN channel data rates even at higher Bit Error Rates (BERs). Selective retransmission events have been incorporated for inevitable part of video bit stream without causing a noticeable drop in objective or subjective media quality. Moreover, proposed error frame forwarding approach exhibits higher link saving even at higher BER with acceptable visual quality
Comparative Study of the Properties of ZnO Layers Grown by MBE and RF Sputtering Techniques
No full textIn recent years ZnO has received the great attention especially due to its potential for the applications such as piezoelectric films used for surface acoustic wave devices (SAW) (Serhane et al., 2014), visible light emitting devices (Rakhshani, 2014), and UV sensing. The electrical, optical, photochemical, and optoelectronic properties of undoped ZnO can be effectively employed for their use in solar cells (Ren et al., 2015), transparent electrodes and blue/UV light emitting devices (Shen et al., 2014). Thus, it is very important to grow the ZnO films with a good crystalline quality along with good understanding of defects. \ud
This work includes the comparison of the properties of ZnO layers grown by MBE and RF Sputtering technique. The XRD pattern clearly shows that the films grown by both methods are highly c-axis oriented, but the film grown by MBE is of better quality. PL results also confirm the findings from the XRD data. MBE grown sample exhibit a band-gap emission at 3.36 eV, while the sample grown by RF sputtering technique shows a NBE emission at 3.26 eV. The electrical characterization was performed by depositing a Au Schottky contact to the grown samples. At room \ud
temperature the values of the ideality factor and barrier height obtained are 2.68 and 0.68 eV respectively. In order to investigate the deep levels, DLTS study is performed on both the MBE grown and RF- Sputtering grown sample. A hole trap with activation energy of 0.43 eV is observed in the MBE- grown sample and in the light of literature survey suggested due to the Zinc-vacancy. Contrary to this, the sample grown by RF Sputtering technique shows the electron trap at 0.33 eV below the conduction band and it is assigned the Zinc interstitial defect. \ud
This thesis also includes the characterization of phosphorus doped ZnO pellets by a simple solid state reaction method. Characterization of as-prepared ZnO pellets was performed by various diagnostic techniques: e.g., X-ray diffraction confirmed hexagonal structure of ZnO pellets. By increasing the sintering temperature, we have observed forward shift in 2 value of the (002) peak, this shift is only observed in the phosphorus doped samples. We correlate the forward shift with the involvement of phosphorus with vacancy at Zn site. Theoretical calculations on a 32-atoms super cell of phosphorus doped ZnO further supported the argument in the shape of a shallow acceptor PZn - 2VZn complex on Zn site. Typical PL spectra displayed band-to-band transitions peak and an additional donor-acceptor peak at ~3.14 eV in phosphorus doped samples. \ud
We have also performed the I-V and C-V measurements on the Zn and O- faces of ZnO grown by hydrothermal method. it was found that the series resistance RS and the ideality factor n is related with temperature that is reduced with increasing temperature for both the faces (Zn and O-face) of ZnO. These result shows that thermionic emission is not the dominant process. The calculated value of barrier height \ud
???I?V? is directly proportional to temperature for both faces. The values of barrier height \ud
???C?V? obtained from C-V measurements were greater than the values of barrier height \ud
???I?V?.Thus, calculated values of ideality factor, barrier height, and series resistance shows that O-polar face is qualitatively better than Zn-polar face. \ud
\ud
Furthermore, we have also grown the ZnO nanorods and nanowires by VS and VLS technique respectively.VLS technique is the known growth technique for the growth of one-dimensional ZnO nanorods or nanowires. The ZnO nanorods were grown at 650oC and the rods were approximately 1.3 m long. Contrary to this, ZnO nanowires were grown at high temperature of 950oC with a clear indication of the gold tip, confirming the growth mechanism is the VLS. We further doped the ZnO wires with the Sb. The incorporation of the Sb in to the ZnO increases the length of ZnO nanowires