Active suppression of machine tool chatter

PhD ThesisThe aim of the work described in this thesis is to design, build, and test an active, chatter suppression system for use on a lathe. Many methods have been developed to minimise the effects of regenerative chatter in machine tools. These include machine redesign and stiffening, the inclusion of additional damping, and the use of passive and active control systems. The method described here is a development of two of these active methods, those of Comstock and Nachtigal, which control the relative position of the cutting tool. An on-line digital computer is used to monitor the cutting force, predict the relative tool-workpiece displacement, and drive the tool to suppress chatter build-up. The work is described in five main sections. After the introductary section, in which the problem is outlined and past work discussed, a theoretical analysis of chattering and its suppression is presented. Digital simulation is used to confirm and expand the theoretical results. The basic on-line identification method used to investigate the machine-workpiece structure is also presented. The third section describes the design and implementation of the experimental rigg especially the computer system and the tool positioner. Its use as a driver for a cheap, bolt-on CNC turning system is also discussed. The fourth section details the experimental work including calibration, cutting tests, suppressor validation and testing. Finally, the theory, simulation and experiments are discussed and related to past work. Suggestions are made for further reearch and development, including other applications of the system. Conclusions are drawn about the various techniques used during the work, with comments on the effectiveness of the suppression method.Science Research Counci

Aligning the planets: The role of nurses in the care of patients with non-ST elevation myocardial infarction.

BACKGROUND: Studies have shown variation in care for patients with non-ST elevation myocardial infarction (NSTEMI), including in the roles of specialist and advanced practice nurses in diagnosis, treatment and coordination of care. AIM: The aim of this study was to describe the roles and responsibilities of specialist and advanced practice nurses in providing care for patients with NSTEMI. METHODS: Secondary analysis of observational field notes and interviews from an ethnographic study of variation in care for NSTEMI patients in 10 UK hospitals conducted 2011-2012. Data were thematically analysed to identify key concepts and themes related to the roles of specialist nurses. RESULTS: Seven of 10 hospitals had roles for specialist nurses in NSTEMI care. The major theme related to high demand and the complexity of patients and organizations ('Aligning the planets'). In this theme, nurses contributed to improving services or compensating for deficiencies ('Making the system work versus making up for the system'). Data collection for audit could take precedence over time with patients ('Paying worship to the paper'). Nurses expressed a sense of ownership of cardiovascular patients that drove their desire to provide quality of care ('They are our patients').This study was funded through a Research for Patient Benefit grant from the National Institute of Health Research, UK.This is the final version of the article. It first appeared from Wiley via https://doi.org/10.1002/nop2.6

Nicotine Modulates The Expression Of A Diverse Set Of Genes In The Neuronal Sh-Sy5Y Cell Line

Nicotine exposure can have long lasting effects on nervous system function, some of which must contribute to nicotine dependence. Up-regulation, an increase in numbers of radioligand-binding nicotinic acetylcholine receptors (nAChR), occurs on exposure to nicotine at high concentrations. To determine whether altered gene expression might account for long term changes and up-regulation following nicotine exposure, we assessed effects of 1 h of 1 mM nicotine exposure on alter. ation of gene expression in the neuron-like SH-SY5Y neuroblastoma clonal line. Repeat and cross-controlled microarray analyses yielded a list of 17 genes from the initially screened ∼5,000 whose expression was consistently altered following nicotine treatment. Subsequent quantitative, real time reverse transcriptase PCR analyses confirmed altered expression in 14 of 16 genes tested. Further, the general nAChR antagonist, d-tubocurarine, blocked all but two of the observed changes in gene expression, indicating that these changes are dependent on nAChR activation. Use of other antagonists revealed that nAChR subtypes can differentially affect gene expression. The genes affected code for proteins that may be broadly categorized into four groups: transcription factors, protein processing factors, RNA-binding proteins, and plasma membrane-associated proteins. Our results suggest that nicotinic activation of nAChR may have a broad role in affecting cellular physiology through modulating gene expression

Genomic and Proteomic Biomarker Discovery in Neurological Disease

Technology for high-throughout scanning of the human genome and its encoded proteins have rapidly developed to allow systematic analyses of human disease. Application of these technologies is becoming an increasingly effective approach for identifying the biological basis of genetically complex neurological diseases. This review will highlight significant findings resulting from the use of a multitude of genomic and proteomic technologies toward biomarker discovery in neurological disorders. Though substantial discoveries have been made, there is clearly significant promise and potential remaining to be fully realized through increasing use of and further development of -omic technologies

Development of a Knowledge Management System Integrated with Local Communication Channels and Knowledge Management Initiatives for Kenyan Rural Farming Communities

yesThis paper presents an innovative application of wireless, mobile and ubiquitous technologies to support informal and collaborative learning in Kenyan rural farming communities. Such an approach is achieved by the development of a knowledge management system (KMS) integrated with existing local community communication channels, together with experimental knowledge management (KM) initiatives employing the VeSeL (Village e-Science for Life) distributed resource kits (DRKs). The initiatives support illiterate and semi-literate farming community groups, in learning new agriculture practices, and also enable the use of advanced digital technology to improve their agricultural practices and literacy levels. Results of a recent field trip to Kenya are presented and an application sketch is developed. The process of applying wireless and Internet technologies for the education of local farming communities, using irrigation and water management as the application, concludes the paper.EPSR

Brans-Dicke model constrained from Big Bang nucleosynthesis and magnitude redshift relations of Supernovae

The Brans-Dicke model with a variable cosmological term ($BD\Lambda$) has been investigated with use of the coupling constant of $\omega=10^4$. Parameters inherent in this model are constrained from comparison between Big Bang nucleosynthesis and the observed abundances. Furthermore, the magnitude redshift ($m-z$) relations are studied for $BD\Lambda$ with and without another constant cosmological term in a flat universe. Observational data of Type Ia Supernovae are used in the redshift range of $0.01<z<2$. It is found that our model with energy density of the constant cosmological term with the value of 0.7 can explain the SNIa observations, though the model parameters are insensitive to the $m-z$ relation.Comment: Submitted to A&A, 4 pages, 3 figure