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To Chris McGregor

- Unknown

Authors: Unknown
Subjects: McGregor, Chris--1936-1990 , Blue Notes (Musical group : South Africa) , Brotherhood of Breath (Musical group) , Trio Wodrascka , Wodrascka, Christine , Jazz , Jazz musicians
Language: French
Identifier: vital:13531 , http://hdl.handle.net/10962/d1006260 , McGregor, Chris--1936-1990 , Blue Notes (Musical group : South Africa) , Brotherhood of Breath (Musical group) , Trio Wodrascka , Wodrascka, Christine , Jazz , Jazz musicians
Description: Photocopied article from the French newspaper Le Journal de Toulouse about a tribute concert to Chris McGregor by the Trio Wodrascka. A photo of the Trio Wodrascka is with the article.
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Tool wear monitoring in end milling of mould steel using acoustic emission

- Olufayo, Oluwole Ayodeji

Authors: Olufayo, Oluwole Ayodeji
Subjects: Acoustic emission testing , Tool-steel
Language: English
Type: Thesis , Masters , MEngineering
Identifier: vital:9651 , http://hdl.handle.net/10948/d1014688
Description: Today’s production industry is faced with the challenge of maximising its resources and productivity. Tool condition monitoring (TCM) is an important diagnostic tool and if integrated in manufacturing, machining efficiency will increase as a result of reducing downtime resulting from tool failures by intensive wear. The research work presented in the study highlights the principles in tool condition monitoring and identifies acoustic emission (AE) as a reliable sensing technique for the detection of wear conditions. It reviews the importance of acoustic emission as an efficient technique and proposes a TCM model for the prediction of tool wear. The study presents a TCM framework to monitor an end-milling operation of H13 tool steel at different cutting speeds and feed rates. For this, three industrial acoustic sensors were positioned on the workpiece. The framework identifies a feature selection, extraction and conditioning process and classifies AE signals using an artificial neural network algorithm to create an autonomous system. It concludes by recognizing the mean and rms features as viable features in the identification of tool state and observes that chip coloration provides direct correlation to the temperature of machining as well as tool condition. This proposed model is aimed at creating a timing schedule for tool change in industries. This model ultimately links the rate of wear formation to characteristic AE features.
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Tribological characteristics of polymers under high force small oscillating angular contact

- Bradfield, Jarad Wade

Authors: Bradfield, Jarad Wade
Subjects: Tribology , Polymers.
Language: English
Type: Thesis , Masters , MTech (Mechanical Engineering)
Identifier: vital:9637 , http://hdl.handle.net/10948/d1020598
Description: This study was intended to establish which polymer material is best suited as the material for bushes used in high force small oscillating angular contact applications as typically found in a large sugar mill coupling. A Tribometer as well as a designed and manufactured Bearing Testing Machine, which simulates and accelerates the wear caused in the intended application, was used to determine the wear rates and coefficients of friction for seven polymer materials. Materials were selected for their superior mechanical and thermal properties. The Tribometer was fitted with a linear reciprocating rig, so as to simulate the small oscillating movement prevalent in the intended application. Each Tribometer test ran for a duration of two hours with a frequency of 33.1 Herts and a normal loading of 40N. Bearing Testing Machine tests were done under similar constraints but with 30kN loading present on the surface of a bushes inner race. These tests had a longer duration of 24 or 48 hours or until intense wearing occurred. Initially both testing methods will be analysed independently of each other in order to try and identify a relationship between the wear rate and coefficient of friction for the different polymers. The different testing methods’ results will be compared to each other in order to establish if a correlation between the materials tested could be found.
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Tuning the physico-electrochemical properties of novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine complex using phenylamine-functionalised SWCNTs

- Agboola, Bolade Oyeyinka, Ozoemena, Kenneth I., Nyokong, Tebello, Fukuda, Takamitsu, Kobayashi, Nagao

Authors: Agboola, Bolade Oyeyinka , Ozoemena, Kenneth I. , Nyokong, Tebello , Fukuda, Takamitsu , Kobayashi, Nagao
Language: English
Type: Article
Identifier: vital:7238 , http://hdl.handle.net/10962/d1019689
Description: The integration of phenylamine-functionalised SWCNTs (SWCNT-phenylamine) with a novel cobalt (II) octa[(3,5-biscarboxylate)-phenoxy] phthalocyanine (CoOBPPc) complex has been described. The physical and electrochemical properties of the CoOBPPc-SWCNT-phenylamine hybrid were evaluated using spectroscopy (IR and UV–vis), field emission scanning electron microscopy and electrochemistry (cyclic voltammetry and electrochemical impedance spectroscopy). Integration of SWCNT-phenylamine resulted in the physical transformation of the CoOBCPPc from the usually bluish colour of cobalt phthalocyanine complexes to a beautiful bright green colour. In addition, the heterogeneous electron transfer kinetics and electrocatalytic properties of the CoOBCPPc were greatly enhanced following the attachment of the SWCNT-phenylamine. The potential electrocatalytic application of the hybrid was tested using β-nicotinamide adenine dinucleotide (NADH) as a model biological analyte. Interestingly, the onset oxidation potential of this analyte was significantly reduced (300 mV) by this hybrid compared to the bare electrode. , Original publication is available at http://dx.doi.org/doi:10.1016/j.carbon.2009.10.023
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Ultrafast Photodynamics of the Indoline Dye D149 Adsorbed to Porous ZnO in Dye-Sensitized Solar Cells

- Rohwer, Egmont, Richter, Christoph, Heming, Nadine, Strauch, Kerstin, Litwinski, Christian, Nyokong, Tebello, Schlettwein, Derck, Schwoerer, Heinrich

Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
Language: English
Type: Article
Identifier: vital:7326 , http://hdl.handle.net/10962/d1020576
Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. , Original publication is available at http://dx.doi.org/10.1002/cphc.201200715
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