Replication as a strategy in capital intensive industries

Researchers describing replication strategies have proposed theoretical constructs that are positively associated with successful replication. In a rigorous quantitative exploration of replication in capital intensive industries, this study is the first of its kind and seeks to prove the applicability of the theoretical frameworks. Responses to questionnaires sent to petrochemical refining sites, coupled with an independent performance metric (the Solomon Associates Comparative Performance Assessment Index) were used to model the impact of replication practices on site performance. This model is used to show that firms attempting to centrally define an Arrow Core suffer a performance penalty. Furthermore, the model shows that a clear differentiation between the phases of exploration and exploitation is not a requirement for successful replication in capital intensive industries. The model helps to explain why barriers exist preventing the conceptualisation of the core capabilities within capital intensive industries; why companies seeking to locally control deleterious practices are negatively impacted compared to those implementing centralised mechanisms; and why the effective use of a template yields a performance advantage even in the absence of a well defined Arrow Core. The analysis also suggests appropriate practices for managers seeking to expand in capital intensive sectors.Dissertation (MBA)--University of Pretoria, 2010.Gordon Institute of Business Science (GIBS)unrestricte

Closed loop performance monitoring

Proportional, Integral and Derivative feedback control (PID) is a mature technology responsible for the majority of automated decision making in the process industry. Despite the high reliance on this technology, low levels of maintenance and performance measurement are the norm in the process industry. Several analysis techniques exist for identifying oscillation, and then highlighting the root cause of the problem. Several time and frequency domain statistical techniques, as well as wavelet analysis are used to diagnose loop performance. In this study, 127 different control loops are analysed, and in depth troubleshooting is performed on a selection of 18 different control loops. The performance of flow loop F1035 is tracked through a number of different analysis techniques, highlighting the pitfalls of using only a single analysis technique. Lower order statistics and minimum variance performance analysis show that the loop is performing well. Plotting the PV-OP relationship suggests non-linear tendencies on F1035, and this is corroborated using high order statistical analysis (bicoherence). Non-linear loop behaviour is often as a result of a slip stick cycle, a sign that valve maintenance may be required. Frequency (power spectrum) analysis shows a 43 minute dominant oscillation, suggesting a low frequency disturbance affecting loop performance. Process units are typically exposed to cyclic behaviour occurring at several different frequencies, each having a different effect on the control of the process. By using a frequency based approach based on sinusoidal basis functions (ie Fourier analysis), these different frequencies get aggregated. This smudging of specific frequency information makes it difficult to pin-point the root cause, and makes the grouping of common oscillations difficult. In order to address the above issue, F1035 is analysed using othornormal wavelet basis functions. The results show that the period of oscillation is affected between day and night, with roughly a 2 minute oscillation prevalent at mid night, compared to a 100 minute oscillation at mid day. Obviously the 12 hour day-night swing is also prevalent. This information is unique to this approach. Ways of visualising changes in oscillatory behaviour using the wavelet analysis are also presented. Technical analysis of controller performance is only a small subsection of the issues that need to be considered when implementing a loop monitoring and maintenance solution. Issues such as connectivity, configuration, analysis, reporting and auditing are key in designing a workable maintenance environment for PID loop maintenance. Several packages are available commercially to assist industry in performing loop maintenance. When evaluating which package is best suited to a specific requirement, it is important to consider several different issues. The different audiences with a vested interest in loop performance require special attention in terms of reporting requirements. Visualisation of results is often more important than the physical measure of performance. Finally, the ability of a company to benchmark itself against current best practices and performance is often perceived as a major advantage. The results presented and discussed were generated using real industrial data. Information regarding suggested best practice when evaluating commercially available products is based largely on the author’s personal experience in the large scale industrial installation of such a monitoring solution.Dissertation (MEng (Process Control))--University of Pretoria, 2007.Chemical Engineeringunrestricte

Differential Effects of Reserpine by Sexes in Breeding Turkeys

Poultry Scienc

Dose-Duration Reciprocity for G protein activation: Modulation of kinase to substrate ratio alters cell signaling

In animal cells, activation of heterotrimeric G protein signaling generally occurs when the system’s cognate signal exceeds a threshold, whereas in plant cells, both the amount and the exposure time of at least one signal, D-glucose, are used toward activation. This unusual signaling property called Dose-Duration Reciprocity, first elucidated in the genetic model Arabidopsis thaliana, is achieved by a complex that is comprised of a 7-transmembrane REGULATOR OF G SIGNALING (RGS) protein (AtRGS1), a Gα subunit that binds and hydrolyzes nucleotide, a Gβγ dimer, and three WITH NO LYSINE (WNK) kinases. D-glucose is one of several signals such as salt and pathogen-derived molecular patterns that operates through this protein complex to activate G protein signaling by WNK kinase transphosphorylation of AtRGS1. Because WNK kinases compete for the same substrate, AtRGS1, we hypothesize that activation is sensitive to the AtRGS1 amount and that modulation of the AtRGS1 pool affects the response to the stimulant. Mathematical simulation revealed that the ratio of AtRGS1 to the kinase affects system sensitivity to D-glucose, and therefore illustrates how modulation of the cellular AtRGS1 level is a means to change signal-induced activation. AtRGS1 levels change under tested conditions that mimic physiological conditions therefore, we propose a previously-unknown mechanism by which plants react to changes in their environment

Effect of Tree Barriers on Outcrossing in Corn

The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Effect of the Waxy Gene on Grain Yields of Sorghum

The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Evolutionary relationships in Panicoid grasses based on plastome phylogenomics (Panicoideae; Poaceae)

Background: Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. Results: 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. Conclusions: The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved.Fil: Burke, Sean V.. Northern Illinois University; Estados UnidosFil: Wysocki, William P.. Northern Illinois University; Estados UnidosFil: Zuloaga, Fernando Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Craine, Joseph M.. Jonah Ventures; Estados UnidosFil: Pires, J. Chris. University of Missouri; Estados UnidosFil: Edger, Patrick P.. Michigan State University; Estados UnidosFil: Mayfield Jones, Dustin. Donald Danforth Plant Science Center; Estados UnidosFil: Clark, Lynn G.. Iowa State University; Estados UnidosFil: Kelchner, Scot A.. University of Idaho; Estados UnidosFil: Duvall, Melvin R.. Northern Illinois University; Estados Unido