• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 675
  • 224
  • 169
  • 153
  • 95
  • 69
  • 39
  • 31
  • 27
  • 25
  • 16
  • 12
  • 9
  • 8
  • 8
  • Tagged with
  • 1902
  • 250
  • 143
  • 133
  • 132
  • 131
  • 130
  • 117
  • 114
  • 106
  • 101
  • 99
  • 98
  • 96
  • 93
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Membrane Modeling, Simulation and Optimization for Propylene/Propane Separation

Alshehri, Ali 06 1900 (has links)
Energy efficiency is critical for sustainable industrial growth and the reduction of environmental impacts. Energy consumption by the industrial sector accounts for more than half of the total global energy usage and, therefore, greater attention is focused on enhancing this sector's energy efficiency. It is predicted that by 2020, more than 20% of today's energy consumption can be avoided in countries that have effectively implemented an action plan towards efficient energy utilization. Breakthroughs in material synthesis of high selective membranes have enabled the technology to be more energy efficient. Hence, high selective membranes are increasingly replacing conventional energy intensive separation processes, such as distillation and adsorption units. Moreover, the technology offers more special features (which are essential for special applications) and its small footprint makes membrane technology suitable for platform operations (e.g., nitrogen enrichment for oil and gas offshore sites). In addition, its low maintenance characteristics allow the technology to be applied to remote operations. For these reasons, amongst other, the membrane technology market is forecast to reach $\$$16 billion by 2017. This thesis is concerned with the engineering aspects of membrane technology and covers modeling, simulation and optimization of membranes as a stand-alone process or as a unit operation within a hybrid system. Incorporating the membrane model into a process modeling software simplifies the simulation and optimization of the different membrane processes and hybrid configurations, since all other unit operations are pre-configured. Various parametric analyses demonstrated that only the membrane selectivity and transmembrane pressure ratio parameters define a membrane's ability to accomplish a certain separation task. Moreover, it was found that both membrane selectivity and pressure ratio exhibit a minimum value that is only defined by the feed composition, product purity and the recovery ratio. These findings were utilized to develop simple and accurate empirical correlations to predict the attainability behavior in real membranes, which showed good agreement with experimental and simulation results for various applications. Furthermore, the attainability of the most promising two and three-stage membrane systems are discussed by considering the complete well mixed assumption. The same behaviors that describe single-stage attainability are also recognized for multiple-stages. This discussion leads to a major discovery regarding the nature of the relationship between the attainability parameters in a multiple-stage membrane system with that of a single-stage system. Study of the economics of the multiple-stage membrane process for propylene/propane separation identifies the technology as a potential alternative to the conventional distillation process, even at the existing membrane performance, but conditionally at low to moderate membrane cost and sufficient durability. To study the energy efficiency of membrane retrofitting to an existing distillation process, a shortcut method was developed to calculate the minimum practical separation energy (MPSE) of the membrane and distillation processes. It was discovered that the MPSE of the hybrid system is only determined by the membrane selectivity and the applied transmembrane pressure ratio in three stages. At the first stage, when selectivity is low, the membrane process is not competitive to the distillation process. At the second medium selectivity stage, the membrane/distillation hybrid system can help to reduce the energy consumption; the higher the membrane selectivity the lower the energy requirement. The energy conservation is further improved as the pressure ratio increases. At the third stage, when both the selectivity and pressure ratio are high, the hybrid system will change to a single-stage membrane unit, resulting in a significant reduction in energy consumption. The energy at this stage continues to slowly decrease with selectivity but increases slightly with pressure ratio. Overall, the higher the membrane selectivity, the more energy that is saved. These results should be very useful in guiding membrane research and their applications. Finally, an economic study is conducted concerning hypothetical membranes and the necessity for low cost and more durable membranes rises as the key for a viable hybrid process.
32

The Influence of Social Determinants on Late Stage Breast Cancer and the Impact of the National Breast and Cervical Cancer Program on Late Stage Breast Cancer Diagnosis

Fortune, Melody L 09 December 2011 (has links)
This dissertation research focused on breast cancer and social determinants that have been shown to influence the outcomes of this devastating disease. Although heart disease is the leading cause of death for women, more women feel that they will die from breast cancer. Breast cancer is the most common diagnosed cancer in women exacting an emotional and economic hardship for many women. There are no known causes of breast cancer, but there are certain genetic and social factors that pre-dispose women to this disease. Also, diagnosis at later stages of disease has been shown to have adverse outcomes for many. This research examined the effects that social determinants had on breast cancer stage of diagnosis. The social determinants researched to examine their influence on breast cancer outcomes were race, geographical location, health insurance, and income. Also, this research examined the influence of Public Health Law, 101-354, enacted to decrease health disparity from breast and cervical cancer for minorities and medically underserved women had on breast cancer diagnosis for women enrolled in the Mississippi Breast and Cervical Cancer Program. Complimentary to PHL 101-354, Public Health Law 106-354, the Breast and Cervical Cancer Treatment Act, was enacted giving states the option of providing health insurance through Medicaid for eligible women with a diagnosis of cancer of the breast or cervix, including precancerous conditions, for treatment services. The results of this study revealed that race and health insurance were the two major factors that negatively impacted stages of breast cancer diagnoses. Although hypothesized, geographical location and income did not significantly affect late stage breast cancer rates.
33

Thymidine kinase activities in white blood cells and serum in cancer patients

O'Neill, K. L. January 1986 (has links)
No description available.
34

Self-care in patients undergoing renal replacement therapy : a critical evaluation of the application of Orem's self-care model of nursing

Fok, Sin Mai January 1999 (has links)
No description available.
35

Crucible the musical? stage managing The Crucible at the University of Iowa

McGlaughlin, Katy Brooke 01 May 2018 (has links)
Arthur Miller’s The Crucible was produced in the fall of 2017 as part of the University of Iowa’s Department of Theatre Arts’ Mainstage season. Director Doug Scholz-Carlson took an innovative approach to the production adding an octet of singers singing Sacred Harp hymns. This thesis explores the production process from the stage manager’s perspective. Because leadership, communication, and organization are essential attributes of stage manager, Katy McGlaughlin’s personal leadership, communication, and organization goals and outcomes for this production are addressed. McGlaughlin concludes her exploration with final thoughts on the production and her development as a Graduate Stage Manager at the University of Iowa.
36

none

Hsiao, Ming-hui 13 July 2007 (has links)
none
37

CORRELATIONS AMONG EXAMINATION FINDINGS, SUBJECTIVE SYMPTOMS AND CLASSIFICATION OF STAGES IN VIBRATION SYNDROME

NAKAMOTO, MINORU, HARADA, NORIAKI, FUTATSUKA, MAKOTO, SAKAKIBARA, HISATAKA, YAMADA, SHIN'YA 05 1900 (has links)
No description available.
38

A study of 10-bit, 100Msps pipeline ADC and the implementation of 1.5-bit stage

Bayoumy, Mostafa Elsayed 15 April 2014 (has links)
The demand on high resolution and high speed analog-to-digital converters (ADC’s) has been growing in today’s market. The pipeline ADC’s present advantages compared to flash or successive approximation ADC techniques. The high-resolution, high-speed requirements can relatively easier be achieved using pipelined architecture ADC’s than other implementations of ADC’s of the same requirements. Because the stages work simultaneously, the number of stages needed to obtain a certain resolution is not constrained by the required throughput rate. Latency is a result of a multistage concurrent operation of any pipelined system. But luckily enough, latency isn’t considered to be a problem in many ADC applications. In this work, a 1.5-bit stage in the pipeline ADC is completely implemented including its two voltage comparators, a DAC with three possible output voltages, and a multiplying digital to analog (MDAC) blocks. Only ideal components were used for clocking operation. At the end of design, a total harmonic distortion (THD) of less than -70 dB was achieved. / text
39

A comparative study of institutions involved in the training of scenic artists / Microsoft Word - Document1

Bezuidenhout, Pieter Andries. January 2010 (has links)
Thesis (MTech. degree in Performing Arts) -- Tshwane University of Technology. 2010. / The training of students for the technical side of the Entertainment Industry in South Africa is not something that has been with us for many years. It is only for the last 33 years that an institution, the then Technikon Pretoria, started a course that trains Scenic Artists in South Africa. Not many institutions are training Scenic Artists in South Africa, and the current Department of Entertainment Technology has always been the leader in this field. In the United Kingdom, training students as Scenic Artists has been part of their programmes for the last ninety years. One finds that there is a demand for training Scenic Artists in the United Kingdom, because of the size and complexity of the Entertainment Industry there. During the Apartheid era, South Africa was excluded from the International scene, so the demand did not really exist here for a number of years. Lately, the Entertainment Industry in South Africa has picked up momentum and expanded its borders immensely, and this has created a great demand for trained Scenic Artists in South Africa. Today one can proudly say that one is part of an industry that trains people as Scenic Artists in South Africa that contributes to the global Entertainment Industry. The Scenic Artists who completed their studies at TUT are employed nationally and internationally, and deliver a very high standard of work on the most impressive projects. During the research that was done between the Tshwane University of Technology in South Africa and the Rose Bruford College and Guildhall School of Drama and Music, both in the United Kingdom in London, one can see that there are no major differences between the three institutions. Each institution has its own methodology, but at the end, all are working towards one goal, and that is to train the best Scenic Artists possible. The differences that present it are in the course structure, available facilities and the amount of staff allocated to do the training.
40

Exploring commitment of secondary teachers in Seychelles

Comarmond, Odile Andrine Louise de January 2013 (has links)
This thesis reports on an investigation into teacher commitment in secondary schools in Seychelles. The overarching aim was to gain an insight into the experiences and perceptions of teacher commitment in order to get a better understanding of teachers’ career trajectories and issues relating to teacher retention. Another aim was to explore the experiences and perceptions of the participating teachers, headteachers and policymakers on the factors that influence commitment and trajectories of secondary teachers at the different stages of their teaching careers. In order to achieve these aims a qualitative methodology was chosen with a combination of three different approaches: phenomenography, phenomenology and multiple case studies. The use of multiple-approaches was considered appropriate in order to enhance the results of the investigation of such a complex phenomenon like teacher commitment. The case studies focused on four teacher groups representing newly qualified teachers, mid-career teachers, experienced teachers and teachers who had left the profession. Data were sought from different participant groups in relation to teacher commitment, experiences and career trajectories. The exploration involved semi-structured interviews with secondary teachers, headteachers and policymakers. The findings show that participants describe teacher commitment in relation to altruism, personal qualities, pedagogical content knowledge and connectedness. The ideas of what constitutes a committed teacher for these participants reveal complexity in the phenomenon of teacher commitment. Personal, organisational and contextual factors are found to influence these participants’ understandings. The findings identify a complex interplay of personal and contextual spheres of influence on teacher commitment. Another level of complexity that the findings revealed relate to the interconnection between teacher commitment, teachers’ career stages and retention. The commitment of beginning teachers is found to be more at risk than that of mid-career and experienced teachers. Education stakeholders hold different views to those of teachers on the factors that impact on teacher commitment and retention. The study concludes by proposing a conceptual model for teacher commitment that illustrates its complex nature. Teacher commitment is multifaceted and the nature and level of commitment held by teachers involves the constant negotiation between these different factors. The findings of the study contribute to a nuanced understanding of teacher commitment and have the potential to generate more in-depth and extensive studies of this phenomenon. These findings may inform policymakers both in Seychelles and in other national and international contexts about issues relating to teacher recruitment, development and retention, which are worldwide concerns.

Page generated in 0.0427 seconds