Stretch forming of thermoplastic fibre-metal laminates

Fibre--metal laminates are sandwich materials comprised of altering layers of fibre-reinforced composites and metal alloys. These materials can offer superior properties compared to the monolithic constituents such as superior specific strength compared to metals and better impact and fatigue resistance than composite materials. The use of fibre--metal laminates is currently restricted to specialised applications where the superior properties justify the high cost. This is due to the increased manufacturing time and cost over conventional materials. A method for mass production of fibre--metal laminates would allow them to be integrated more easily into existing production facilities and greatly reduce the cost associated with their use. This thesis investigates the stamp formability of fibre--metal laminates using two distinct materials; one laminate based on a self-reinforced polypropylene composite and the other based on a glass-fibre reinforced polypropylene composite. Specimens of varying geometry were stretched over a hemispherical punch to elicit different deformation modes in the fibre--metal laminates and a non-contact optical measurement system was used to measure the surface strain during deformation. These experiments analysed the effect of the deformation mode on the formability of the laminates. The results from the experimentation were used to assess the deformation behaviour of the fibre--metal laminates and to identify the safe forming limits of the materials. It was found that the fibre--metal laminates can be formed in a similar manner to monolithic metals. The self-reinforced polypropylene laminate was found to exhibit superior formability to monolithic aluminium whereas the glass-fibre reinforced polypropylene laminate showed reduced formability. In addition, the effect of temperature on the formability of the laminates was investigated. The temperature did not have a significant effect on the deformation behaviour during the forming process in either fibre--metal laminate and no increased formability was exhibited by the glass-fibre reinforced polypropylene based laminate. However, the self-reinforced polypropylene based laminate showed improved formability at elevated temperatures. Two significant findings were identified; the friction interaction between the specimens and the tooling has a major effect on the forming of the laminates, and the forming limits of the aluminium are improved when bonded to self-reinforced polypropylene composite. The finite element analysis software ABAQUS/Standard was chosen for simulation of fibre--metal laminate forming. Tensile tests were performed to obtain the mechanical behaviour of the constituent materials, where the composites were simulated using non-linear elastic orthotropic material models and the aluminium using an elastic-plastic model. The experimental forming results were compared to the simulation and it was found that the simulation could accurately represent the general forming behaviour of the laminates. There was difficulty in matching some of the glass-fibre reinforced polypropylene laminates due the non-homogeneous behaviour of the composite. Results from the simulated specimens were used to assess the deformation of the composite, which could not be directly observed in the experiments, and to determination a preliminary failure condition of the composite experiencing stretch forming using the predicted strain in the failure region

Brethren upon the same level : membership and class in Calumet\u27s Masonic Lodge

The Keweenaw Peninsula of Upper Michigan was a ethnic conglomerate of cultures and ideas, with people attracted to the area by the mineral wealth found along the Copper Range. The center of copper mining from the mid 1860s to 1968 was in the vicinity of Calumet Township, home to the world-famous Calumet and Hecla Mining Company. The township depended on the mines and the company’s president Agassiz’s strove to make the area a “model community,” that included groups such as the Free and Accepted Masons. Men from myriad backgrounds arrived in Calumet from the British Isles, Germany, Finland, Eastern and Southern Europe and the Eastern United States. As in other communities from the time period these men formed common interest groups like Masonic Lodge 271, which received its charter in 1870. Gentlemen joined with merchants and craftsmen. They became “brethren upon the same level,” and were elevated to the status of Master Mason. This symbolic transformation within the Lodge removed the men from the “profane world” outside the sanctity of Masonry, and in the ritualistic transformation of the meeting they were reborn into Masonry’s sacred mysteries. Masonry acted as a means of moral guidance to men and gave them access to a larger social and economic community through a common connection of brotherhood. As the candidates moved through the three Blue Lodge degrees of Entered Apprentice, Fellowcraft, and Master Mason they saw each other as “brethren upon the same level” – all economic classes equal within the Masonic Lodge. To examine equality within Lodge 271, this study sorted workers into classes to allow a comparison of Lodge 271’s membership. Possibly a comparison between other lodges can be drawn from the membership. The Union Building in Calumet, MI will be examined for its role in the ritualistic transformation of Masonry as it housed Masonic activities and transformations. This transformation brought men into the lodge of brothers. While Masonry professed equality between members however, to what extent did the membership of the lodge reflect this between the brethren? To what extent did economic class determine who was made “brethren upon the same level? 1 Arthur Thurner, Calumet Copper and People: History of a Michigan Mining Community, 1864-1970 (Hancock, MI: Book Concern, 1974), 122

The Effect of Two Weight Reduction Maintenance Strategies for Moderately/Mildly Retarded Adults

Thirteen retarded adult subjects were first exposed to a 12-week behavior therapy weight reduction program followed by a ten-month weekly weigh-in. Then the subjects were randomly assigned to an experimental maintenance booster session group (n=7) or a control post-treatment maintenance group (n=6) for 12 months. The results indicated that when weight control or maintenance procedures were in effect, the subjects lost weight. However, a 12-month follow-up check revealed that the long-term success of the treatment and maintenance procedures was not well maintaned

Stretch forming studies on a fibre metal laminate based on a self-reinforcing polypropylene composite

This paper investigates the room temperature formability of a fibre metal laminate system comprised of aluminium and a self-reinforcing polypropylene composite. Blanks of varying geometry were stretch formed over a hemispherical punch in a custom built stamping press. A real-time three-dimensional photogrammetric measuring system was used to acquire the evolution of surface strain and the strain at failure during forming. The results from this work illustrate that these advanced light weight material systems are amenable to mass production through stamp forming. A significant finding from this work is that these material systems can exhibit forming characteristics that are comparable and sometimes superior to metal forming

Assembly and Disassembly of DNA Polymerase Holoenzyme

The complex task of genomic replication requires a large collection of proteins properly assembled within the close confines of the replication fork. The mechanism and dynamics of holoenzyme assembly and disassembly have been investigated using steady state and pre-steady state methods as opposed to structural studies, primarily due to the intrinsic transient nature of these protein complexes during DNA replication. The key step in bacteriophage T4 holoenzyme assembly involves ATP hydrolysis, whereas disassembly is mediated by subunit dissociation of the clamp protein in an ATP-independent manner

Assembly and Disassembly of DNA Polymerase Holoenzyme

The complex task of genomic replication requires a large collection of proteins properly assembled within the close confines of the replication fork. The mechanism and dynamics of holoenzyme assembly and disassembly have been investigated using steady state and pre-steady state methods as opposed to structural studies, primarily due to the intrinsic transient nature of these protein complexes during DNA replication. The key step in bacteriophage T4 holoenzyme assembly involves ATP hydrolysis, whereas disassembly is mediated by subunit dissociation of the clamp protein in an ATP-independent manner

Protein-Protein and Protein-DNA Interactions at The Bacteriophage T4 DNA Replication Fork. Characterization of a Fluorescently Labeled DNA Polymerase Sliding Clamp

The T4 DNA polymerase holoenzyme is composed of the polymerase enzyme complexed to the sliding clamp (the 45 protein), which is loaded onto DNA by an ATP-dependent clamp loader (the 44/62 complex). This paper describes a new method to directly investigate the mechanism of holoenzyme assembly using a fluorescently labeled cysteine mutant of the 45 protein. This protein possessed unaltered function yet produced substantial changes in probe fluorescence intensity upon interacting with other components of the holoenzyme. These fluorescence changes provide insight into the role of ATP hydrolysis in holoenzyme assembly. Using either ATP or the non-hydrolyzable ATP analog, adenosine 5′-O-(3-thiophosphate), events in holoenzyme assembly were assigned as either dependent or independent of ATP hydrolysis. A holoenzyme assembly mechanism is proposed in which the 44/62 complex mediates the association of the 45 protein with DNA in an ATP-dependent manner not requiring ATP hydrolysis. Upon ATP hydrolysis, the 44/62 complex triggers a conformational change in the 45 protein that may be attributed to the clamp loading onto DNA

Systems and methods for short range RF communication

A method transmitting a message over at least one of a plurality of channels of a communications network is provided. The method comprises the steps of detecting a presence of jamming pulses in the at least one of the plurality of channels. The characteristics of the jamming pulses in the at least one of the plurality of channels is determined wherein the determined characteristics define at least interstices between the jamming pulses. The message is transmitted over the at least one of the plurality of channels wherein the message is transmitted within the interstices of the jamming pulse determined from the step of determining characteristics of the jamming pulses

Instability in the Molecular Dynamics Step of Hybrid Monte Carlo in Dynamical Fermion Lattice QCD Simulations

We investigate instability and reversibility within Hybrid Monte Carlo simulations using a non-perturbatively improved Wilson action. We demonstrate the onset of instability as tolerance parameters and molecular dynamics step sizes are varied. We compare these findings with theoretical expectations and present limits on simulation parameters within which a stable and reversible algorithm is obtained for physically relevant simulations. Results of optimisation experiments with respect to tolerance prarameters are also presented