HORIZONTAL FLOW LOOP DESIGN FOR THE STUDY OF DRILL STRING ROTATION EFFECTS ON CUTTINGS TRANSPORT

Exploration and Production companies are continually focusing more time, energy and resources into Extended Reach Drilling in order to maximize reservoir production while minimizing both environmental impact and development costs. These long laterals (2:1 Measured Depth: True Vertical Depth) are often more difficult to drill and can be severely impacted by inadequate drilling practices. Cuttings transport efficiency is a critical parameter of Extended Reach Drilling operations, and poor wellbore cleaning can lead to excessive torque, drag, and several other serious downhole problems. Although many studies have been performed that identify the importance of drill string rotation on cuttings movement, there is still much to be learned about the correlation between rotation and hole cleaning. This increase in transport cuttings efficiency is more pronounced in larger diameter holes, where often sudden increases in transport efficiency occur when drill string rotation nears both 120 and 180 RPM. This document presents a design of a flow loop capable of emulating downhole flow conditions and high RPM drill string rotation in a large diameter wellbore, which would allow for the study and better understanding of this phenomenon. This design will also be the first that allows drill string interchangeability and adjustment of drill string centerline within the casing, further increasing research capabilities. A comprehensive computational fluid dynamics (CFD) model has also been designed. This model will be used alongside the flow loop and will be refined and validated by future flow loop experiments. This flow loop and CFD model can be used to develop working correlations and provide real world predictive models. A strong comprehension of these step changes in cuttings removal rates could allow for the development of new technology or drilling practices that could replicate this effect, increasing transport efficiency dramatically. With the ever-increasing importance of successful Extended Reach Campaigns, companies are relying heavily on technological and operational breakthroughs to push the envelope of Extended Reach

The Influence of Cortisol, Flow, and Anxiety on Performance in E-Sports: A Field Study

Background and Objectives. Most performance theories were tested under controlled laboratory settings and offer therefore only limited transferability to real-life situations. E-sport competitions offer a relatively controllable while at the same time competitive setting, and our aim was to examine different influencing factors on competitive performance. Design and Methods. Salivary cortisol was measured immediately before, after, and 30 minutes after a game of 23 computer players during e-sport tournaments. The players answered the Flow Short Scale, which consists of the two subdimensions “flow experience” and “anxiety” subsequent to their game. The performance was assessed by the result of each player’s game (win or loss). Results. Mean cortisol levels increased significantly during the game but response patterns were inconsistent. Winners and losers differed significantly in anxiety with winners showing higher anxiety levels. After dividing the sample into three groups of different cortisol response patterns, significant differences in performance and anxiety were found, with low to moderate levels of cortisol being associated with the highest performance and anxiety. Conclusions. A low to moderate physiological arousal and a simultaneously high level of anxiety represent a favorable state for achieving optimal performance during e-sports. Anxiety seems to exert a stronger influence on performance than physiological arousal

Single waveguide silicon-organic hybrid modulator

We present a novel silicon-organic hybrid modulator based on an integrated dual-mode interferometer. The modulator offers a compact, simplified design and enhanced robustness to on-chip fluctuations of temperature compared to conventional Mach-Zehnder based systems. A prototype modulator showing a voltage dependent transmission spectrum is obtained by cladding a dual-mode waveguide in a 250 nm silicon-on-insulator technology with a customized organic electro-optic layer. Estimated phase shifts and corresponding figures of merit are discussed in this contribution. The used organic layer is based on the guest-host approach with customized donor-acceptor chromophore embedded and poled in a poly(methylmethacrylate) matrix. The presented prototype is to the best of the authors'' knowledge the first integrated single waveguide silicon-organic hybrid modulator

Indigenous knowledges and development: a postcolonial caution

As a result of the failure of formal top-down development, there has recently been increased interest in the possibilities of drawing upon the indigenous knowledges of those in the communities involved, in an attempt to produce more effective development strategies. The concept of indigenous knowledge calls for the inclusion of local voices and priorities, and promises empowerment through ownership of the process. However, there has been little critical examination of the ways in which indigenous knowledges have been included in the development process. Drawing upon postcolonial theory, this article suggests that indigenous knowledges are often drawn into development by both theorists and development institutions in a very limited way, failing to engage with other ways of perceiving development, and thus missing the possibility of devising more challenging alternatives

Charge-induced conformational changes of dendrimers

We study the effect of chargeable monomers on the conformation of dendrimers of low generation by computer simulations, employing bare Coulomb interactions. The presence of the latter leads to an increase in size of the dendrimer due to a combined effect of electrostatic repulsion and the presence of counterions within the dendrimer, and also enhances a shell-like structure for the monomers of different generations. In the resulting structures the bond-length between monomers, especially near the center, will increase to facilitate a more effective usage of space in the outer-regions of the dendrimer.Comment: 7 pages, 12 figure

Social research on neglected diseases of poverty: Continuing and emerging themes

Copyright: © 2009 Manderson et al.Neglected tropical diseases (NTDs) exist and persist for social and economic reasons that enable the vectors and pathogens to take advantage of changes in the behavioral and physical environment. Persistent poverty at household, community, and national levels, and inequalities within and between sectors, contribute to the perpetuation and re-emergence of NTDs. Changes in production and habitat affect the physical environment, so that agricultural development, mining and forestry, rapid industrialization, and urbanization all result in changes in human uses of the environment, exposure to vectors, and vulnerability to infection. Concurrently, political instability and lack of resources limit the capacity of governments to manage environments, control disease transmission, and ensure an effective health system. Social, cultural, economic, and political factors interact and influence government capacity and individual willingness to reduce the risks of infection and transmission, and to recognize and treat disease. Understanding the dynamic interaction of diverse factors in varying contexts is a complex task, yet critical for successful health promotion, disease prevention, and disease control. Many of the research techniques and tools needed for this purpose are available in the applied social sciences. In this article we use this term broadly, and so include behavioral, population and economic social sciences, social and cultural epidemiology, and the multiple disciplines of public health, health services, and health policy and planning. These latter fields, informed by foundational social science theory and methods, include health promotion, health communication, and heath education