Long range dependent processes occur in many fields, it is important to monitor these processes to early detect their shifts. This paper considers the problem of detecting changes in an I(d) process or an ARFIMA(p,d,q) process by statistical control charts. The control limits of EWMA and EWRMS control charts of I(d) processes are established and analytic forms are derived. The average run lengths of these control charts are estimated by Monte Carlo simulations. In addition, we illustrate the performance of the control charts by empirical examples of I(d) processes and ARFIMA(1,d,1) processes.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1973. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

The main topic of this diploma thesis is process management and Business Process reengineering (BPR) and applied research of this concept in a particular company. In the theoretical part at first I define the concept of process and process management, which I then develop with BPR. In addition, the basic methodologies, including metadata of modeling a business process analysis (MMABP) are defined and described. I also present the modeling language Unifield Modeling Language (UML), Eriksson-Penker notation and the Business Process Modeling Notation (BPMN). On the basis of this theoretical part, I implement applied research in a specific research area.

The aim of this diploma thesis is look at ways of optimising business processes in a specific company acting as an insurance intermediary. The thesis consists of a theoretical part which defines the basic concepts of the issue. The analytical part maps the current state of the business processes in the company, which serves as the foundation of a proposal for their optimization with the use of a CRM system.

This master’s thesis is focused on optimizing logistics processes of a business in order to reduce overall costs. Thesis is divided into two parts, theoretical and practical. The theoretical part includes logistics trends, cost, technology, logistics and logistics information technology. The practical part is performed analysis of business processes. Finally, as the point is to assess the situation and suggestions for improvement.

Thesis (DEng (Process Engineering))--University of Stellenbosch, 2005. / This dissertation covers research carried out over the past 25 years in the area of flotation. Flotation is one of the most widely used processes in the beneficiation of minerals. The process is characterized by a number of important sub-processes each with their own set of critical variables. These include: • The pulp phase which is influenced by variables such as pH, Eh, the nature of the chemical reagents used, the chemical state of the surface of the ore particles, etc. • The reactor in which the process occurs, viz. the flotation cell, which is influenced by factors such as aspect ratio, degree of agitation, mechanical design criteria, energy input, aeration processes, etc. • The froth phase which is arguably the heart of the process and probably the least well understood but which is influenced by factors such as size and shape of the solid particles in the froth, the nature of the surfactant used, the aeration rate, the water recovery rate, the froth depth, etc.

Thesis (MScIng)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: Spherical wax particles with diameters of 5 μm and less are known to enhance the properties of powder and solvent-based coatings. Conventional methods, including spray freezing and jet milling, yield only 15 – 20 % of particles within this desired size range. Recently, supercritical fluids have been used in the micronisation of a variety of polymers, pharmaceuticals and other inorganic solids. Of these processes, the Rapid Expansion of Supercritical Solutions (RESS) involves the expansion of a solid dissolved in a supercritical fluid over a nozzle. In the process the solubility of the solid is drastically decreased to yield high supersaturated conditions, resulting in a multitude of small and stable wax nuclei. The technique is known to produce small, solvent free particles with a narrow size distribution. In this project, the RESS technique was applied to two commercial Fischer-Tropsch waxes: Paraflint C80 and Paraflint C105. Propane was selected as supercritical solvent due to its increased solvent power for paraffin wax compared to other conventional supercritical solvents such as carbon dioxide and ethane. From theoretical studies, nozzle geometry, as well as nozzle inlet temperature, pressure and concentration was identified as the parameters most likely to influence the size and shape of the wax particles. Porous plate nozzles were chosen as expansion device due to lower pressure drop and higher flow rate of the expanding solution compared to conventional capillary nozzles. Pre-expansion conditions of 125 to 160 ºC and 125 – 180 bar were investigated. Wax concentrations up to 5 weight % were expanded through porous plate nozzles with pore sizes of 15, 25 and 60 μm. It was found that small particles, less than 5 μm in size could readily be produced for the whole range of parameters investigated. Average particle sizes of less than 2 μm were found in virtually all cases. The C80 particles tended to be less smooth and of more angular shape than C105 particles. It is argued that the higher fraction of low weight compounds softens the C80 wax particle surface, making them more susceptible to deformation and coagulation. Experimental studies confirmed that a combination of lower temperature and higher pressure (175 bar and 130 ºC) increases the chances for the formation of spherical particles. This combination corresponded to conditions furthest away from the dew point of the solution. The 25 μm porous plate nozzle gave better results than the other nozzles, indicating that the characteristics of the nozzle could play a more important role than the pore size. SEM images indicated that this nozzle has a larger porosity, which could have resulted in lower pressure drops compared to the other nozzles. Higher wax concentration did seem to give smaller individual particles, but particle shape visibly deteriorated as the concentration increased. From experiments with C105 wax, at these optimal conditions, it seems as if a maximum concentration between 4 and 5 % is achievable, above which the particle shape became flak-like with rough edges. Due to limitations of the batch experimental set-up, especially regarding the reaching of steady state, it is strongly recommended that the obtained results be verified on pilot plant scale, where longer spray times can be achieved. The RESS process for wax micronisation on industrial scale needs to be critically examined and higher pressure and solvent recycling costs would need to be weighed up against the lower wax recycling required to obtain the desired particles. / AFRIKAANSE OPSOMMING: Sferiese was partikels met ’n deursnee van 5 μm en minder is bekend daarvoor dat dit die eienskappe van ’n verskeidenheid van poeier en oplosmiddel-gebaseerde deklae verbeter. Alledaagse metodes, waaronder sproeivries- en maalprosesse soos straalmaling, lewer slegs sowat 15 – 20 % van die partikels binne die gewenste partikelgrootte. In die afgelope tyd is superkritiese vloeistof mikroniseringsprosesse gebruik om ’n verskeidenheid van polimere, farmaseutiese en ander anorganiese stowwe te mikroniseer. Die sogenaamde “Rapid Expansion of Supercritical Solutions (RESS)”– proses behels die ontspanning van ’n oplossing van die vaste stof en ’n superkritiese oplosmiddel oor ’n spuitstuk. In die proses verlaag die oplosbaarheid van die vaste stof drasties, sodat hoë superversadigde vlakke in ’n baie kort tydperk bereik word om ’n menigte klein en stabiele was kerne te vorm. Die tegniek is bekend daarvoor om fyn, oplosmiddelvrye partikels met ’n nou partikelgrootteverspreiding te lewer. In hierdie projek is die RESS-proses ondersoek om twee Fischer-Tropsch wasse, C80 en C105, te mikroniseer. Propaan is as oplosmiddel gekies weens die verhoogde oplosbaarheid van paraffienwasse daarin vergeleke met ander konvensionele superkritiese oplosmiddels soos koolsuurgas en etaan. Poreuse skywe is as spuitstukke verkies weens die feit dat hoër vloeitempos en laer drukvalle oor hierdie spuitstukke verkry kan word. Na ’n teoretiese ondersoek is spuitstukgeometrie, asook die temperatuur, druk en konsentrasie by die spuitstukinlaat geïdentifiseer as die prosesparameters wat die partikelgrootte en –verspreiding die waarskynlikste sal beïnvloed. Daar is besluit om die spuitstukinlaatkondisies van 125 tot 160 ºC en 125 tot 180 bar te ondersoek. Waskonsentrasie tot en met 5 massa % is deur poreuse skywe met gemiddelde poriegroottes van 15, 25 en 60 μm ontspan. Klein waspartikels, met gemiddelde partikelgroottes van minder as 2 μm is in feitlik al die gevalle verkry. Die C80 waspartikels het geneig om minder glad en meer hoekig as die C105 partikels te wees. Hier word vermoed dat die hoër hoeveelheid lae massa komponente die C80 waspartikeloppervlak versag en dit meer vatbaar maak vir vervorming en koagulasie. Eksperimentele studies het getoon dat ’n kombinasie van laer temperature en hoër drukke (175 bar en 130 ºC) by die spuitstukinlaat die kanse vir sferiese partikels vergroot. Hierdie temperatuur/druk kombinasie val saam met toestande verder weg van die doupunt van die oplossing. Sover dit die spuitstukke aanbetref, het die 25 μm poreuse skywe beter resultate as die ander spuitstukke gelewer. Hier word vermoed dat die fisiese eienskappe van die spuitstuk ’n meer prominente rol as die poriegrootte speel. SEM foto’s het getoon dat hierdie spuitstuk ’n groter porositeit, wat ’n laer druikval tot gevolg kon gehad het, in vergelyking met die ander spuitstukke. Dit blyk asof hoër waskonsentrasies lei tot kleiner individuele partikels, maar die vorm en oppervlak daarvan het sigbaar verswak by hoër konsentrasie. Vanuit eksperimente met C105 was, by die bovermelde optimale kondisies, wil dit voorkom asof ’n maksimum konsentrasie tussen 4 en 5 % haalbaar is, voordat die partikels ’n vlokkierige vorm met ruwe oppervlak aangeneem het. Weens die beperkinge van die eksperimentele opstelling, word dit ten sterkste aanbeveel dat die resultate op loodsaanlegskaal, waar langer sproeitye moontlik is, bevestig word. Die RESS-proses behoort krities ondersoek te word en die hoër druk en oplosmiddel hersirkuleringskoste moet opgeweeg word teenoor die voordele van die laer was hersirkulering benodig om die gewenste partikels te lewer.

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Protecting modern engineered systems has become increasingly difficult due to their complexity and the difficulty of predicting potential failures. With the added threat of terrorism, the desire to design systems resilient to potential faults has increased. The concept of a resilient system – one that can withstand unanticipated failures without disastrous consequences – provides promise for designing safer systems. Resilience has been recognized in research settings as a desired end product of specific systems, but resilience as a general, inherent, measurable property of systems had yet to be established. To achieve this goal, system resilience was related to an established concept, the resiliency of a material. System resilience was defined as the amount of energy a system can store before reaching a point of instability. The energy input into each system as well as the system’s exergy were used to develop system stress and system strain variables. Process variable changes to four test systems – a steam pipe, a water pipe, a water pump, and a heat exchanger – were applied to obtain series of system stress and system strain data that were then graphed to form characteristic system response curves. Resilience was quantified by performing power-law regression on each curve to determine the variable ranges where the regression line accurately described the data and where the data began to deviate from that power-law trend. Finally, the four test systems were analyzed in depth by combining them into an overall system using the process simulator ASPEN. The ranges predicted by the overall system data were compared to the ranges predicted for the individual equipment. Finally, future work opportunities were outlined to show potential areas for expansion of the methodology.

The present dissertation describes the efforts directed towards the development of computational tools to support process modeling. This work is also a further development of the Thermoslag® software developed in the Division of Materials Process Science, KTH. The essential parts of the thesis are a) development of a semi-empirical model for the estimation of the molar volumes/densities of multicomponent slags with a view to incorporate the same in the model for viscosities and b) further development of the viscosity model for application towards fluoride- and manganese containing slags, as for example, mould flux slags and manganese slags used in ferromanganese production. c) estimating fluoride emissions from industrial slags and mould fluxes. d) study the reaction between carbon particles, hematite containing slags and in oxygen containing atmosphere. The model for the estimation of molar volume is based on a correlation between the relative integral molar volume of a slag system and the relative integral molar enthalpies of mixing of the same system. The integral molar enthalpies of the relevant systems could be evaluated from the Gibbs energy data available in the Thermoslag® software. The binary parameters were evaluated from experimental measurements of the molar volumes. Satisfactory correlations were obtained in the case of the binary silicate and aluminate systems. The model was extended to ternary and multi component systems by computing the molar volumes using the binary parameters. The model predictions showed agreements with the molar volume data available in literature. The model was used to estimate the molar volumes of industrial slags as well as to trace the trends in molar volume due to enable prediction of molar volumes of slags that are compatible with the thermodynamic data available. With a view to extend the existing model for viscosities to F--containing slags, the viscosities of mould flux slags for continuous casting in steel production have been investigated in the present work. The measurements were carried out utilizing the rotating cylinder method. Seven mould fluxes used in the Swedish steel industry and the impact of Al2O3 pick up by mould flux slags on viscosities were included in the study. The results showed that even relatively small additions of Al2O3 are related with a significant increase in viscosity. A similar experimental technique was employed to estimate the viscosity of twelve synthetic slags corresponding to composition of the raw materials used in ferromanganese production. The flow rate of the liquid slag, which is determined by the slag viscosity, is an important parameter affecting the reduction rate of manganese oxide. The results show a clear correlation between manganese oxide content and viscosity. An increase of MnO in the slag lowers the viscosity. The measured viscosities have also been connected to the structure of the silicates. The fluoride loss from the binary slag systems Al2O3-SiO2, CaO-SiO2 and MgOSiO2 with additions of CaF2 was studied by thermogravimetric (TGA) studies. The Arrhenius activation energy for the evaporation reaction of fluorides was found to be dependent on temperature and slag chemistry for the slags studied. A correlation between the activation energy for fluoride evaporation and activity of SiO2 in the slag melt was established. This relationship obtained for the binary systems appears also to be suitable for the ternary systems Al2O3-CaO-SiO2 with CaF2 addition, which indicates a possibility to estimate the fluoride emissions from industrial slags and mould fluxes. A Confocal Scanning Laser Microscopy was used to investigate the reaction between carbon particles in hematite containing slags and in oxygen containing atmosphere. Experiments with varying temperature and slags with varying FeOx content were carried out. The general trends were that the particle size decrease was more rapid with increase of FeOx amount and/or temperature was increased. / QC 20100812