1,139 research outputs found
Investigating Gravity and Electromagnetism on a 10 Dimensional Manifold with Local Symmetry so(2,3)
The Hawthorn model [1] is built upon the idea that the Lie algebra so(2, 3) is a more natural description of the local structure of space-time than the Poincare Lie algebra, with the former contracting to the latter in the limit of the contraction parameter r tending to infinity. This notion is explored in the context of a 10-dimensional space-time referred to as an ADS manifold. Here we build on the work of Crump [2] and try to incorporate field equations for gravity into the model. We derive two apparently different equations describing gravitational phenomena, demonstrate an intimate connection between gravity and electromagnetism and provide a first estimate as to the value of the contraction parameter r
A study of the extent to which displacement is a significant theme in the use of the Old Testament in Matthew’s infancy narrative
Matthew’s Gospel was written in a historical context of displacement, the community from which this text emerged likely experienced displacement as a result of the Jewish Roman War. The Infancy narrative (Matt 1-2) presents a number of references to forced displacement. These two chapters also make extensive use of the OT. This thesis seeks to bring together a discussion of the use of the OT in Matthew’s Infancy narrative and a discussion of the significance of the theme of displacement. The thesis will discuss two questions: To what extent is displacement a significant theme in Matthew’s infancy narrative, and where the theme of displacement can be established, how is the OT used within the text to present and expound on the theme?
This study concludes that displacement is a theme which the Matthean author seeks to evoke. Matthew’s text supports the argument that as a displaced people the Matthean community sought to understand their situation by reflecting upon themes of displacements in the OT
3D Analysis of Structures at the Kambalda Nickel Mines, Western Australia
The Kambalda Nickel Mines are a type example of massive nickel sulphide deposits located in the 2.7 Ga Archaean Eastern Goldfields Province, Yilgarn Craton, Western Australia. Nickel sulphide deposits are hosted in embayments, known as troughs, in the contact between Lunnon Basalt and the overlying Kambalda Komatiite. This contact is structurally complex as a result of several phases of compressive deformation after ore formation. The troughs and the orebodies they host define a linear pattern, trending NNW-SSE sub-parallel to each other and the regional structural trend. I This thesis proposes a new model for the origin of these troughs which is based on a comparison with extensional structures seen in the Holocene volcanic fissure swarms of Iceland. It is argued that Kambalda ore troughs were originally similar extensional structures formed synvolcanically during a previously undocumented early extensional event. This early extension created the NNW-SSE tectonic grain that characterises the eastern portion ofthe Yilgarn Craton. The model is developed to explain unusual thrust structures on the Kambalda Dome. These thrusts represent footwall shortcuts formed during subsequent compressive deformation which partially inverted the original graben bounding faults. However three-dimensional kinematic modelling of the Kambalda Dome and Tramways fold-thrust structures suggests they are not inversion anticlines above the regional scale BoulderLefroy Fault. The relationship between these structures and the Boulder-Lefroy Fault remains ambiguous. It is suggested that the regional Foster, Tramways and Democrat-Republican thrusts are thick-skin structures, hence precluding models invoking a regional thrust duplex. The new model presented in this thesis for the early structural history of the Kambalda area provides an explanation for many of the geologic features observed today in the Kambalda areaImperial Users onl
Formation of inorganic submicron particles under simulated pulverized coal combustion conditions
Thesis (Sc.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1982.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.Bibliography: leaves 246-250.by Matthew Neville.Sc.D
Aerobic power and peak power of elite America’s Cup sailors
Big-boat yacht racing is one of the only able bodied sporting activities where standing armcranking
(‘grinding’) is the primary physical activity. However, the physiological capabilities of
elite sailors for standing arm-cranking have been largely unreported. The purpose of the study was
to assess aerobic parameters, VO2peak and lactate threshold (OBLA), and anaerobic performance,
torque- and power-crank velocity relationships and therefore peak power (Pmax) and optimum
crank-velocity (ωopt), of America’s Cup sailors during standing arm-cranking. Thirty-three elite
professional sailors performed a step test to exhaustion, and a subset of ten grinders performed
maximal 7 s isokinetic sprints at different crank velocities, using a standing arm-crank ergometer.
VO2peak was 4.7(0.5) L/min (range: 3.6-5.5 L/min) at a power output of 332(44) W (range: 235-
425 W). OBLA occurred at a power output of 202(31) W (61% of Wmax) and VO2 of 3.3(0.4)
L/min (71% of VO2peak). The torque-crank velocity relationship was linear for all participants
(r=0.9(0.1)). Pmax was 1420(37) W (range: 1192-1617 W), and ωopt was 125(6) rpm. These data are
among the highest upper-body anaerobic and aerobic power values reported. The unique nature of
these athletes, with their high fat-free mass and specific selection and training for standing arm
cranking, likely accounts for the high values. The influence of crank velocity on peak power
implies that power production during on-board ‘grinding’ may be optimised through the use of
appropriate gear-ratios and the development of efficient gear change mechanisms
Losses Optimization of Induction Motor Using Genetic Algorithm
In this work, Genetic Algorithm (GA) has been used as an optimization technique to minimise the losses in an
induction machine. It was been observed that the GAs locate the global optimum region faster than the conventional
direct search optimization techniques. In this paper, the concept of GA was used as an optimization technique to
minimize the losses in an electric machine thereby improving on the efficiency. The result shows an improvement in
the machine’s efficiency from 90.3% to 94.3%
Influence of crank length and crank-axle height on standing arm-crank (grinding) power
To determine the optimal crank length and crank-axle height for maximum power
production during standing arm-cranking (‘grinding’). Nine elite professional America’s Cup grinders (age: 36 ± 2 y; body mass: 104 ± 1 kg; body fat 13 ± 2%) performed eight maximal 6 s sprints on an adjustable standing arm-crank ergometer fitted with an SRM powercrank. The protocol included crank lengths of 162, 199, 236
and 273 mm and crank-axle heights of 850, 950, 1050 and 1150 mm. Peak power, ground reaction forces (GRF) and joint angles were determined and compared for different crank lengths and crank-axle heights with repeated-measures ANOVA. Results: Peak power was significantly different between crank lengths (P=0.006), with 162 mm lower than all others (P<0.03). Optimal crank length was 12.3% of arm-span, or 241 ± 9 mm for
this cohort of athletes. Peak power was significantly less for the crank-axle height of 850 mm compared to 1150 mm (P=0.01). The optimal crank-axle height for peak power was between 50 and 60% of stature (950-1150 mm in this study). Hip flexion was greater at the lowest crank-axle height (850 mm) than at 1050 and 1150 mm (P<0.01), and the resultant GRF was also reduced compared to all other heights, indicating greater weight bearing by the upper body. Changes in crank length and crank-axle height influence performance during maximal standing arm-crank ergometry. These results, suggest that standard leg-cycle crank lengths are inappropriate for maximal arm-cranking performance. In addition, a crank-axle height
of <50% of stature, which is typically used in America’s Cup sailing, may attenuate performance
Aerodynamic levitator furnace for measuring thermophysical properties of refractory liquids
The development of novel contactless aerodynamic laser heated levitation techniques is reported that enable thermophysical properties of refractory liquids to be measured in situ in the solid, liquid, and supercooled liquid state and demonstrated here for alumina. Starting with polished crystalline ruby spheres, we show how, by accurately measuring the changing radius, the known density in the solid state can be reproduced from room temperature to the melting point at 2323 K. Once molten, by coupling the floating liquid drop to acoustic oscillations via the levitating gas, the mechanical resonance and damping of the liquid can be measured precisely with high-speed high-resolution shadow cast imaging. The resonance frequency relates to the surface tension, the decay constant to the viscosity, and the ellipsoidal size and shape of the levitating drop to the density. This unique instrumentation enables these related thermophysical properties to be recorded in situ over the entire liquid and supercooled range of alumina, from the boiling point at 3240 K, until spontaneous crystallization occurs around 1860 K, almost 500 below the melting point. We believe that the utility that this unique instrumentation provides will be applicable to studying these important properties in many other high temperature liquids
The COVID-19 long-term care situation in the islands of Malta and Gozo
1) The pandemic response team had been in place well before the first COVID-19 case was registered in Malta. The first case was registered on the 7 March 2020, and during the first 2 weeks of the pandemic all cases were imported. A mandatory 2-week quarantine was put in place for all in-coming travellers during the second week of the pandemic. 2) Malta’s size and population were potentially favourable towards ensuring better COVID-19 control measures. Nine (9) deaths have been recorded to date. 3) The Superintendent of Public Health together with the COVID-19 Response Team were key towards ensuring effective and timely mitigation efforts both with the general public as well as ensuring that the local health care system was robust enough to meet the needs brought about by the pandemic. 4) The daily medical bulletins broadcast by the Superintendent of Public Health kept the public continually updated on COVID-19 matters. The bulletins provide the Public Health Authority with a publicly accessible platform to focus and strengthen health promotion efforts in respect to the COVID-19 pandemic. 5) Swabbing and contact tracing within the 3 testing hubs on the Island were key towards controlling the pandemic. 6) A series of measures were put in place early on with the key aim of ordering categories of persons referred to as ‘vulnerable’, to remain segregated in their residences, (except in the cases of attendance for medical appointments, obtain medical care or treatment, acquire food, medicine, other daily necessities, or to attend to any other essential or urgent personal matters). 7) The voluntary response by management and health care professionals within the care homes on the Island was paramount towards recording no deaths within these facilities; the majority of care homes were in lockdown for 12 weeks, whilst other care homes worked on 1, 2 or 3 week shifts. Swabbing of health care professionals was mandatory prior to assuming duties within the residential care facilities.
8) As of the 4 May 2020, the Superintendent of Public Health embarked on a stepwise relaxation of measures. The first measure was followed by the second and third relaxation of measures on the 22 May 2020 and 5 June 2020.peer-reviewe
- …