102 research outputs found
LOW TEMPERATURE SPLIT INJECTION SPRAY COMBUSTION: IGNITION, FLAME STABILIZATION AND SOOT FORMATION CHARACTERISTICS IN DIESEL ENGINE CONDITIONS
The aim of the PhD work is to investigate the fundamental differences in combustion behavior when split injections are used in low temperature combustion regime. In this thesis, the first injection is also called as pilot injection and second injection is also called as main injection. The broad aspects which are studied encompassing the investigation is to study the ignition delay, lift-off and soot formation of such a double split spray combustion. The mechanisms of ignition, lift-off and soot production are to be studied since the main ignition and lift-off were found to differ from the pilot which effect net soot production. The planned studies in the present work are divided into 1) experimental and 2) numerical approaches. Experimental approach involves high-speed schlieren and luminosity imaging to visualize the spray/flame progress and qualitative soot formation respectively. This is often coupled in a simultaneous way to the laser-based planar laser induced fluorescence (PLIF) technique to visualize ignition behavior in terms of formaldehyde presence and soot precursor visualization of poly-cyclic aromatic hydrocarbons (PAH). As part of CFD simulations, thorough validations of the fuel liquid length, vapor (mixture) presence, temporal and spatial species (formaldehyde, soot) presence, ignition delay, lift-off length, and heat release rate are performed. The main objective of the proposal work would be to perform experimental research with split injection strategies, simulate them using CFD and then understand the underlying mechanisms of important processes of ignition, lift off mechanisms in subsequent injections and the associated soot production mechanisms
A Methodology to manage victim components using CBO measure
The current practices of software industry demands development of a software
within time and budget which is highly productive. The traditional approach of
developing a software from scratch requires considerable amount of effort. To
overcome the drawback a reuse drive software development approach is adopted.
However there is a dire need for realizing effective software reuse. This paper
presents several measures of reusability and presents a methodology of
reconfiguring the victim components. The CBO measure helps in identifying the
component to be reconfigured. The proposed strategy is simulated using HR
portal domain specific component system.Comment: 10 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1202.560
A bilevel product pricing problem with ranks and utilities: Models and Algorithms
Product pricing is a revenue management strategy that facilitates the determination of the prices of a series of products by understanding customer's purchase behavior to optimize the firm's revenue. It is worth mentioning that contributions in the current literature mainly focuses on a single purchasing behavior of the customer either by using utility or rank. To address this problem, we propose a product pricing model incorporating both the customer's utility and the rank. We present a bilevel programming formulation to model this problem and present its corresponding single level formulation. We present two algorithms to assess the validity of the single level formulation and obtain high-quality solutions in reasonable CPU times. Results of computational experiments are presented to assess the performance
of the proposed algorithms, in comparison with the single level formulation by solving it with a general purpose solver
Design and validation of wearable wireless sensors
Title from PDF of title page, viewed on March 14, 2013Dissertation advisor: W. Daniel Leon-SalasVitaIncludes bibliographic references (p. 102-[113])Thesis (Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2012Recent years have seen an increase in research and development efforts towards
wearable and implantable health monitoring systems. Such systems are needed to provide
real-time information about patients to physicians, care-givers, emergency personnel and
relatives. The challenge lies in their designing as they need to satisfy a variety of criteria
and constraints. These include small weight and size, low power consumption, easy to
use, and should be aesthetically pleasing. Advances in semiconductor fabrication have
made commercially available highly integrated systems-on-chip (SOC) which are being
exploited to develop such systems. Use of these SOCs reduces cost and development
time. This dissertation presents system prototypes that can capture human body motion,
measure strain on bones and perform electromyography (EMG). Design of these systems
is centered on ultra-low power microcontrollers and other required circuit components.
We present in detail their design, functionality and compare our results with present solutions.Introduction -- A wearable motion tracker -- Bone strain measuring telemetry units -- Wireless surface electromyography (EMG) sensor -- Conclusion
The burden of anxiety and depression among patients with chronic rheumatologic disorders at a tertiary care hospital clinic in Karachi, Pakistan
Objectives: To study the burden of anxiety and depression as a comorbid among patients of chronic rheumatological disorders and to investigate possible determinants of depression and anxiety.Methods: It was a cross-sectional study conducted at the rheumatology clinic of The Aga Khan University Hospital (AKUH) Karachi, Pakistan. With convenient sampling, 111 patients who fulfilled inclusion/exclusion criteria were screened for anxiety and depression with help of Aga Khan University Anxiety and Depression Scale (AKUADS). The data was entered and analyzed by Statistical Package for Social Sciences (Version 10.0).Results: The population consisted mainly of middle aged (mean age 41) females (80.2%). The most common diagnosis was rheumatoid arthritis 57% followed by systemic lupus erythmatosis 17% and systemic sclerosis 9%. The permanent joint deformity was present in 33.3% patients and 36.9% patients were suffering from active disease with pain and inflammation. The frequency of anxiety and depression was 65.8%. Educational qualification, permanent joint deformity, active inflammation and time elapsed since diagnosis had significant association with anxiety and depression. Marital Status, gender, economic activity and monthly family income had no effect on the frequency of anxiety and depression.CONCLUSION: Almost two third of patients with chronic rheumatological disorders, also suffered from a concomitant mood disorder. Systematic evaluation of all patients for mood disorders and psychological distress in rheumatology clinics is highly recommended
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