601 research outputs found
The Exclusivity of the Christian Faith: A Case for Christ-Alone in a Culture of Relativism
The proposition of absolute and exclusive truth in a culture permeated by relativism is among the most important discussions of today. The answer to this dilemma is imperative. Relativism has not only taken captive secular society, it has infiltrated the thinking of many professing Christians. The traditional Christian message has always been one of exclusivity and Christ-alone. The challenge for the Christian Apologist in a culture of relativism is three-fold: Establish the existence of absolute and exclusive truth, nullify the arguments presented by relativism as unreasonable, illogical, and fallible, and to make a solid case for the unsurpassable uniqueness of Jesus Christ and the Christian faith. To accomplish this, steps must be taken within the local church to renew a culture of evangelistic apologetics. The exclusivity of Christ-alone and the Christian faith must be presented and established as the right and only alternative to the failed ideology of relativism
Focussed microwave heating using degenerate and non-degenerate cavity modes
Microwave ovens have long been recognised as a means of reducing heating times versus
conventional convection ovens. The principle design feature is based on the procurement
of uniform heating within any material placed in the interior of the microwave cavity
oven. Materials within the oven are subjected to a degree of heating dependent on their
electromagnetic properties. For many applications, it is desirable to maintain control over
the distribution of heat deposition. This can be achieved through focussing of the electromagnetic
field within the cavity. Two new mechanisms are identified where an increased
level of control over the heating pattern and its location could be advantageous.
The research described within this thesis aims to improve heating selectivity in microwave
cavity ovens by the identification and enhanced control of modal patterns in degenerate
and non-degenerate resonators. This is achieved through the analysis of two novel oven
arrangements. The first of these addresses the requirement for highly selective heating in
hyperthermia treatment. It is demonstrated that proper selection of a forced degenerate
mode set can lead to an enhancement in field focussing within the centre of the cavity
through constructive and destructive interference of the fields in each mode pattern. It is
found that a highly selective peak of field can be produced within the centre of a large
cylindrical waveguide cavity for the purpose of hyperthermia treatment. The peak is produced
using a quasi degenerate mode set excited at approximately 1:3GHz.
The second example presents an open oven design for the curing of epoxy and encapsulant
materials within the micro-electronics packaging industry. It is intended that the
oven be placed on the arm of a precision alignment machine such that the curing and
placement stages of production be combined, suggesting an increase in production efficiency.
Two excitation schemes are presented based on the coupling of quasi degenerate
mode sets through a wide frequency range and the excitation of a single high order mode
enabling uniform field distribution for heating of encapsulant material and increased selective
heating through spatial alignment of modal field peaks, respectively.
Experimental results demonstrate the viability of the open-ended microwave oven for curing.
Both proposed excitation methods within the open oven design are investigated with
results presented. Optimisation of the heating fields is achieved through inclusion of lowloss
materials within the oven. Curing of an encapsulant material covering a commercial
chip package is achieved and the overall design validated
Geometrical reasoning in the primary school, the case of parallel lines
During the primary school years, children are typically expected to develop ways of explaining their mathematical reasoning. This paper reports on ideas developed during an analysis of data from a project which involved young children (aged 5-7 years old) in a whole-class situation using dynamic geometry software (specifically Sketchpad). The focus is a classroom episode in which the children try to decide whether two lines that they know continue (but cannot see all of the continuation) will intersect, or not. The analysis illustrates how the children can move from an empirical, visual description of spatial relations to a more theoretical, abstract one. The arguments used by the children during the lesson transcend empirical arguments, providing evidence of how young children can be capable of engaging in aspects of deductive argumentation
Effect of gain and phase errors on SKA1-low imaging quality from 50-600 MHz
Simulations of SKA1-low were performed to estimate the noise level in images
produced by the telescope over a frequency range 50-600 MHz, which extends the
50-350 MHz range of the current baseline design. The root-mean-square (RMS)
deviation between images produced by an ideal, error-free SKA1-low and those
produced by SKA1-low with varying levels of uncorrelated gain and phase errors
was simulated. The residual in-field and sidelobe noise levels were assessed.
It was found that the RMS deviations decreased as the frequency increased. The
residual sidelobe noise decreased by a factor of ~5 from 50 to 100 MHz, and
continued to decrease at higher frequencies, attributable to wider strong
sidelobes and brighter sources at lower frequencies. The thermal noise limit is
found to range between ~10 - 0.3 Jy and is reached after ~100-100 000 hrs
integration, depending on observation frequency, with the shortest integration
time required at ~100 MHz.Comment: 23 pages, 11 figures Typo correcte
An experimental investigation of human mismatches in machining.
Mismatches refer to incompatibilities, inappropriateness, unsuitabilities or inconsistencies
in machine operators’ actions which, if not addressed, would lead to errors. A fuller understanding
of the rate at which mismatches occur and their causes would allow human aspects to be given
proper consideration alongside hardware and technological issues in the design of new working
environments, machines and tasks. This research highlights these human aspects of machining by
examining mismatches in relation to various human characteristics.
The human task–mismatch matching method was developed and applied in manual turning
operations using experimental and questionnaire techniques on groups of 16 skilled and 12 unskilled
operators. The skilled subjects were drawn from local industry and university technical staff.
Unskilled subjects were engineering students, all of whom had some familiarity with machining
through periods of industrial placement. Statistically significant relationships were established
between mismatches and many of the human characteristics studied (skill, age, work experience,
self-confidence and trust) when considering all the subjects as a single group, but for skilled
operators alone, the only significant relationship was between self-confidence and trust.
As a general conclusion, it can be confirmed that studying operators in their own workplace
provides invaluable information for the design and operation of future workplaces, but that the
relationships between performance and human characteristics remain difficult to establish formally
Human mismatches and preferences for automation
The research reported in this paper is concerned with gaining a better understanding of human factors issues in machining and the automation of manufacturing tasks. Mismatches between operators' performance and the requirements of machining tasks were experimentally studied with respect to the relationships with various human characteristics, including skill, age, work experience, self-confidence and trust. Twelve hypotheses concerning interrelationships between these characteristics were evaluated and important relationships established. It is considered that this increased knowledge of the rate of mismatches and an understanding of the causes is essential for the successful design of new working environments, machines and tasks. Much of this change to the working environment is likely to involve some degree of automation of the operators' tasks and so a second and important aspect of the study was designed to establish the extent to which preferred levels of automation were related to the same human characteristics. Four further hypotheses relating preferred levels of automation to skill, age, work experience, self-confidence and trust were tested with results that, in some cases, were unexpected and in others contradict the findings of previous research. © 2000 Taylor & Francis Ltd
High-Q suspended optical resonators in 3C-SiC obtained by thermal annealing
We fabricate suspended single-mode optical waveguides and ring resonators in 3C-SiC that operate at telecommunication wavelength, leverage post-fabrication thermal annealing to minimize optical propagation losses and demonstrate Q of over 41,000
Mitochondrial DNA is critical for longevity and metabolism of transmission stage Trypanosoma brucei.
The sleeping sickness parasite Trypanosoma brucei has a complex life cycle, alternating between a mammalian host and the tsetse fly vector. A tightly controlled developmental programme ensures parasite transmission between hosts as well as survival within them and involves strict regulation of mitochondrial activities. In the glucose-rich bloodstream, the replicative 'slender' stage is thought to produce ATP exclusively via glycolysis and uses the mitochondrial F1FO-ATP synthase as an ATP hydrolysis-driven proton pump to generate the mitochondrial membrane potential (ΔΨm). The 'procyclic' stage in the glucose-poor tsetse midgut depends on mitochondrial catabolism of amino acids for energy production, which involves oxidative phosphorylation with ATP production via the F1FO-ATP synthase. Both modes of the F1FO enzyme critically depend on FO subunit a, which is encoded in the parasite's mitochondrial DNA (kinetoplast or kDNA). Comparatively little is known about mitochondrial function and the role of kDNA in non-replicative 'stumpy' bloodstream forms, a developmental stage essential for disease transmission. Here we show that the L262P mutation in the nuclear-encoded F1 subunit γ that permits survival of 'slender' bloodstream forms lacking kDNA ('akinetoplastic' forms), via FO-independent generation of ΔΨm, also permits their differentiation into stumpy forms. However, these akinetoplastic stumpy cells lack a ΔΨm and have a reduced lifespan in vitro and in mice, which significantly alters the within-host dynamics of the parasite. We further show that generation of ΔΨm in stumpy parasites and their ability to use α-ketoglutarate to sustain viability depend on F1-ATPase activity. Surprisingly, however, loss of ΔΨm does not reduce stumpy life span. We conclude that the L262P γ subunit mutation does not enable FO-independent generation of ΔΨm in stumpy cells, most likely as a consequence of mitochondrial ATP production in these cells. In addition, kDNA-encoded genes other than FO subunit a are important for stumpy form viability
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