1,655 research outputs found
Optimising temperature sensor placement for machine tool thermal error compensation
In this article, results of thermal error assessments are evaluated from a range of modern machine tools operating with active thermal compensation. The standard models assume a linear relationship between temperature and displacement and implementations address only a limited subset of error sources. However, significant residual errors were found on the analysed machines. The aim of this work is to improve the accuracy and increase the scope of compensated errors, without introducing onerous complexity, by using optimised linear correlation models applied to existing controllers
Extreme events and event size fluctuations in biased random walks on networks
Random walk on discrete lattice models is important to understand various
types of transport processes. The extreme events, defined as exceedences of the
flux of walkers above a prescribed threshold, have been studied recently in the
context of complex networks. This was motivated by the occurrence of rare
events such as traffic jams, floods, and power black-outs which take place on
networks. In this work, we study extreme events in a generalized random walk
model in which the walk is preferentially biased by the network topology. The
walkers preferentially choose to hop toward the hubs or small degree nodes. In
this setting, we show that extremely large fluctuations in event-sizes are
possible on small degree nodes when the walkers are biased toward the hubs. In
particular, we obtain the distribution of event-sizes on the network. Further,
the probability for the occurrence of extreme events on any node in the network
depends on its 'generalized strength', a measure of the ability of a node to
attract walkers. The 'generalized strength' is a function of the degree of the
node and that of its nearest neighbors. We obtain analytical and simulation
results for the probability of occurrence of extreme events on the nodes of a
network using a generalized random walk model. The result reveals that the
nodes with a larger value of 'generalized strength', on average, display lower
probability for the occurrence of extreme events compared to the nodes with
lower values of 'generalized strength'
Environmental friendly method for the extraction of cellulose from Triflolium resopinatum and its characterization
The leaves of Triflolium resopinatum were collected from the mountains of Malakand division, Khyber Pukhtoonkhwa, Pakistan and was grinded into smaller particles and converted into powder. The ground biomass was treated with different solvents in the Soxhlet apparatus for the removal of soluble extractive like pectin, cutin and wax substances. For bond breaking the alkaline substance was kept in the autoclave. Ethylene diamine tetra-acetate (EDTA) and hydrogen peroxide (H2O2) were used for the removal of most polar substances like pectin, cutin, waxes and other extractives. Furthermore, raw cellulose was purified through acetic acid and nitric acid. Double distilled water was used for the neutralization of pH.The analysis of purified cellulose was carried out through different procedures such as X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The extracted cellulose has high degree of purity and crystallinity (72%) and thermal stability indicating that the process for the extraction of cellulose is quite adequate.               KEY WORDS: Triflolium resopinatum, Cellulose, FTIR, XRD, TGA, SEM Bull. Chem. Soc. Ethiop. 2019, 33(1), 61-68DOI: https://dx.doi.org/10.4314/bcse.v33i1.
Case Study On The Assessment Of Sinkhole Risk For The Development Of Infrastructure Over Karstic Ground
Practical Applications and Case Studie
Crafting a Systematic Literature Review on Open-Source Platforms
This working paper unveils the crafting of a systematic literature review on
open-source platforms. The high-competitive mobile devices market, where
several players such as Apple, Google, Nokia and Microsoft run a platforms- war
with constant shifts in their technological strategies, is gaining increasing
attention from scholars. It matters, then, to review previous literature on
past platforms-wars, such as the ones from the PC and game-console industries,
and assess its implications to the current mobile devices platforms-war. The
paper starts by justifying the purpose and rationale behind this literature
review on open-source platforms. The concepts of open-source software and
computer-based platforms were then discussed both individually and in unison,
in order to clarify the core-concept of 'open-source platform' that guides this
literature review. The detailed design of the employed methodological strategy
is then presented as the central part of this paper. The paper concludes with
preliminary findings organizing previous literature on open-source platforms
for the purpose of guiding future research in this area.Comment: As presented in 10th IFIP WG 2.13 International Conference on Open
Source Systems, OSS 2014, San Jos\'e, Costa Rica, May 6-9, 201
Learning to breathe with Tai Chi online - qualitative data from a randomized controlled feasibility study of patients with cystic fibrosis
Introduction Tai Chi (TC), a gentle exercise, incorporates meditative movement and respiratory control. The high risk of cross infection for people with cystic fibrosis (CF) requires close management in healthcare settings, limiting group activities such as TC. A mixed-methods randomized controlled feasibility study compared teaching TC over the internet with in-person, face to face TC tuition provided to CF patients. This article explores qualitative data from patients and TC instructors on their attitudes, acceptability and engagement with the two modes of TC delivery. Methods Qualitative data from CF patients (>6 years) were collected using Skype interviews/focus groups and written feedback. TC instructors provided weekly written feedback, and took part in interviews/ focus groups at the end of the study. Patient and instructor interviews explored their experiences and engagement with TC online delivery and ability to practice. Results Irrespective of the type of TC delivery, all CF participants interviewed (n = 28) practiced between lessons and most wanted to continue TC. Teenagers were more likely to miss TC appointments. Internet delivery was well received by both patients and TC instructors. Two patients reported difficulties with screen size/camera and one with internet connectivity. Conclusion Both face-to-face and internet delivery of TC lessons were equally well received and perceived as beneficial. In the current COVID-19 pandemic, CF patients self-isolating could find this intervention provides important support, therefore the programme was made available on YouTube in April 2020 and linked to the websites of the CF charities funding the research
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