The well established practice of applying tip and/or root relief to the teeth of low contact ratio spur gears is reviewed. Results are presented for the experimental validation of a systematic design method for profile relief that depends critically on how far the relief extends along the path of contact. This method has proved to be effective in controlling gear vibration and noise. A good correlation between static transmission error, dynamic transmission error and sound pressure level was found. This allows design rules to be formulated which can be applied to achieve the minimum vibration and noise levels at a given operating load. A computer program was also developed that allows the introduction of measured gear tooth profiles from an involute tester, to predict the static transmission error curves and thus give an indication of gear quality as regards vibration and noise levels for any given simulated operating load or load range. The computer program was extended to take into consideration the more complex geometry of helical gears using the 'Thin Slice' theory. This allows the prediction of the effects of lead crowning, misalignment, pitch errors and various profile reliefs including relief coined "cross relief", where the relief is applied parallel to the base helix angle. An optimisation routine was included in the computer program that systematically varies the extent of profile relief and amount of lead crowning to minimise transmission error. Since the amount of required profile relief is concomitant with extent of relief and amount of lead crowning (load remaining constant), the program iterates to find the correct amount of profile relief to avoid undesirable comer/tip contact. This new approach has facilitated the generalisation of the effects of profile relief on transmission error for a whole range of typical axial and transverse contact ratios for narrow face width helical gears, previous analyses concentrating on specific designs. Results are also presented for the experimental validation of predicted static transmission error in helical gears. A good correlation between static transmission error, dynamic transmission error and sound pressure level was found as in the spur gear analysis.

This dissertation consists of three parts, each devoted to a particular issue of significant importance for CALIPSO lidar observation of depolarization ratio (delta) and backscatter (gamma?) to improve current understanding of the microphysical properties of clouds and aerosols. The relationships between depolarization ratio and backscatter allow us to retrieve particle thermodynamic phase and shape and/or orientation of aerosols and clouds. The first part is devoted to the investigation of the relationships between lidar backscatter and the corresponding depolarization ratio for different cloud classifications and aerosol types. For each cloud and aerosol types, layer-averaged backscatter and backscattering depolarization ratio from the CALIPSO measurements are discussed. The present results demonstrate the unique capabilities of the CALIPSO lidar instrument for determining cloud phase and aerosols subtypes. In the second part, we evaluate the MODIS IR cloud phase with the CALIPSO cloud products. The three possible misclassifications of MODIS IR cloud phasealgorithm, which are studied by Nasiri and Kahn (2008) with radiative transfer modeling, are tested by comparing between MODIS IR phase and CALIOP observations. The current results support their hypotheses, which is that the MODIS phase algorithm may tend to classify thin cirrus clouds as water clouds or mixed phase clouds or unknown, and classify midlevel and/or mid-temperature clouds as mixed or unknown phase. In the third part, we present a comparison of mineral dust aerosol retrievals from two instruments, MODIS and CALIPSO lidar. And, we implement and evaluate a new mineral dust detection algorithm based on the analysis of thin dust radiative signature. In comparison, three commonly used visible and IR mineral dust detection algorithms, including BTD procedure, D parameter method, and multi-channel image algorithm, are evaluated with CALIPSO aerosol classification. The comparison reveals that those dust detection algorithms are not effective for optically thin dust layers, but for thick dust storm. The new algorithm using discriminant analysis with CALIPSO observation is much better in detecting thin dust layer of optical thickness between 0.1 and 2.

The most commonly used transport protocol, TCP (Transport Control protocol) reacts to loss by throttling the transmission rate. This impacts performance if the loss is non-congestion related, corruption loss. A link layer protocol may use ARQ to provide reliability and shield TCP from corruption loss. The advantage of fragmentation together with link ARQ is; it is able to retransmit the requested frame and instead of the entire data packet. For a link to perform transparent fragmentation, an adaption layer (AL) protocol is needed. Although link ARQ may improve TCP performance, it introduces undesirable delay (i.e. receiver side head of line blocking) and negatively impacts the end-to-end TCP performance. This thesis presents new results on the impacts link ARQ have on the <i>cwnd </i>(congestion window) limited TCP sessions sharing the same link ARQ. To minimise the delay, we proposed to use a more assertive link layer protocol (APRIL). To eliminate the interaction between classes of flow sharing the link with ARQ, flow isolation is required. We discussed the role of the virtual channel (VC) and how it can be used to provide flow isolation. We identified the role of the VC as related to the reassembly process at the receiver end. It allows different traffic classes/flows to be reassembled independently. Therefore, multiple reassembly processes are desirable, one for each traffic class/flow. Our novel approach performs reassembly in the link receive buffer, without demultiplexing frames into the respective channel (as in ATM and X.25) to eliminate the interaction between flows sent on different virtual channel. An approach to increase the robustness of sequence number wrapping in a VC reassembly process without increasing the protocol overhead is also proposed. The inefficiency in the multiple reassembly processes is discussed in the thesis. A simple reassembly process requires massive CPU effort at the receiver since it does not know what exists in the buffer before the process is triggered. We proposed the use of three lists, channel, retransmission and suspended list to minimise this inefficiency in the multiple reassembly processes. During link layer frame processing, it updates all the VC encountered in the block in the channel and retransmission lists. The adaption layer can refer back to these lists prior commencing reassembly process. Therefore, irrelevant blocks, frames and VC can be identified and ignored during the reassembly process. We demonstrate that these lists greatly reduced the processing cost.

Experimental cold modelling of hearth drainage was performed at Bluescope Steel Research Laboratories to understand the impact of variable drainage rate on slag removal. These drainage studies were designed to simulate real operational aspects such as: continuous casting, variable tapping rate and inflow liquid distribution. During the analysis of these drainage experiments it was demonstrated that the residual-flowout correlation in use since the 1970??s may possibly be incomplete or inaccurate. The removal of slag from the blast furnace hearth is the greater concern of the two liquids produced in the iron making process. In the 1970??s operational difficulties arose when large volumes of residual slag remained in the furnace after casting. This prompted research related to the flow of viscous liquids through uniformly packed beds providing fundamental insight on the most effective means of removal of slag from the blast furnace hearth. The core subject of this study, the residual-flowout correlation developed by Fukutake and Okabe that is used to predict cast duration and liquid accumulation in the blast furnace hearth is discussed in detail. The residual-flowout correlation is examined for four different sets of conditions based on constant or increasing slag drainage, with and without liquid dripping. The outcome of this study will improve our understanding of the residual-flowout relationship and develop it further, so that drainage conditions whether for constant or increasing drainage rates, with or without dripping, will hold using the one general Fl equation.

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1923. / Cover title. Reprinted from Journal of agricultural research, vol. XXVIII, no. 3 (19 Apr. 1924). Contribution from Bureau of Animal Industry (A-77). "The experimental part of the work was conducted in the Dept. of Genetics, Agricultural Experiment Station, University of Wisconsin, and at Macdonald College, St. Anne d'Bellevue, P.Q. Canada ... Pub. with the approval of the director of the Wisconsin Station as paper no. 46." "Literature cited": p. 221-224.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1932. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [38]-45).

Thesis (Ph. D.)--Washington State University, May 2010. / Title from PDF title page (viewed on July 15, 2010). "Department of Natural Resource Sciences." Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1937. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 37-40).

Thesis (doctoral)--Jyväskylä. / Summary in Finnish. Bibliography: p. 187-191.

They would possibly be less contentious if there was conclusive proof that managers were better allocators of capital generated through income retained than investors. Against this backdrop, this study examines the question of whether correlations exist between the amount of income retained by managers to fund capital and various financial management and investment performance metrics. The objective of the study is to test various hypotheses for relationships between the retention ratio and various management and investment performance metrics. The hypotheses includes testing whether dividends are a significant contributor to investor returns, whether there is a correlation between the retention ratio and the share price, between the retention ratio and total investor returns and between the retention ratio and return on equity. A last hypothesis is to test whether there is a correlation between total returns to investors and return on equity. The results of the study did not support any of the hypotheses and the indication is that no firm or clear relationship between the retention ratio and various performance metrics exists for the sample of South African firms over the survey period, namely share price, total investor returns and return on equity. The study could therefore not conclude whether managers were either good or poor allocators of capital generated through income retained. The study could also not determine whether capital retained did impact on future performance measures of a company or not. This outcome of the study was surprising. It was anticipated that there would be either positive correlations supporting managers’ ability to allocate retained income or negative correlations refuting managers’ ability to allocated retained income. This, however, was not evident. The literature reviewed was clear regarding the mystery surrounding dividend distributions and its role within iii corporate finance, but was divided on the drivers of the behaviour. It was hoped that this study would have been able to provide some explanation for dividends in a South African mining industry context. The reasons for the outcome are varied but include the questionable credibility of the data with regards to the size of the sample and the period of study. Therefore, no certain conclusions could be made about managers’ ability to allocate capital generated through retained income and the recommendation is for further research to be conducted with a larger sample over a longer period of study before the results are given undue significance. / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted