Utility Disturbance Management in the Process Industry

Use of utilities, such as steam and cooling water, is very common at industrial sites. Utilities are often shared between several production areas, and a disturbance in the supply of a utility is therefore likely to affect a large part of the production site, and cause great loss of revenue. In order to minimize the loss of revenue due to disturbances in utilities, the optimal supply of utilities to different areas has to be determined. It is not evident how utility resources should be divided, as both buffer tank levels, the connections between areas and profitability of different areas must be considered. This thesis presents a general method for reducing the loss of revenue due to disturbances in utilities, the Utility Disturbance Management method (UDM). The method concerns identifying disturbances in utilities, estimating the loss of revenue due to such disturbances, and finding strategies for reducing the loss. A model of the production site is needed to complete all steps of the method. In this thesis, some modeling approaches are suggested, and on/off production modeling with and without buffer tanks is described in detail. The UDM method is applied to an industrial site at Perstorp using these two modeling approaches

Hierarchical Scheduling and Utility Disturbance Management in the Process Industry

This thesis deals with control of production at large-scale process industrial sites in the presence of disturbances. The main focus is on disturbances in the supply of utilities such as steam, cooling water and electricity. A general method for reducing the revenue loss due to disturbances in utilities is introduced, which may provide both proactive and reactive disturbance management strategies. Utility availability and area availability are introduced as performance indicators. These measures are used to obtain quick estimations of the revenue losses related to each utility. To obtain reactive strategies for utility disturbance management, a simple model of how utilities affect production in an area, and how utilities are shared between areas, is introduced. The modeling approach is utilized to formulate the production control problem at disturbances in utilities as an optimization problem. Measurement data are used to obtain empirical models of utility disturbances at an industrial site, which may be used as input to the optimization. Since production control closely relates to production scheduling, the integration of production scheduling based on orders and forecasts with production control at disturbances in utilities is studied in the final part of the thesis

Buffer Management Strategies for Improving Plant Availability

In an industrial plant availability is an important factor since increased availability often gives an increase of final production which in many cases means an increased profit for the company. It has been shown that good strategies for buffer management could increase the availability of an entire plant which motivates further research in this area. To be able to compute the optimal solution to a buffer management problem there are many constraints to be specified, among others the topology of the system, the disturbance model and the definition of flow variations. The optimal solution will depend on the choice of constraints and thereby the general buffer management problem becomes very complex. Today a few of the possible problem formulations have been solved but there are still many gaps in the research in this area. The purpose of this thesis is to sort out what has been done in the area of buffer management and to try to fill out some of the gaps. The developed methods and strategies are used for improving buffer management in two plants at Perstorp AB. These case studies reveal some buffer management problems that can be present within the process industry

A method for improving plant availability with respect to utilities using buffer tanks

Disturbances on utilities, such as steam and cooling water, often cause large revenue losses at industrial sites. These disturbances are often hard to handle, since they commonly are plant-wide disturbances that affect more than one production area at the site. Also, the production areas of the site are often dependent on other production areas because of the flow of product through the site, which makes the effect of disturbances on utilities hard to predict. In this paper, a simple method for decreasing the revenue loss due to disturbances on utilities is presented, where production areas are modeled as either operating at full speed or not operating (on/off), and buffer tanks between areas at the site are utilized. Both choice of levels in the buffer tank and control of the product flow at the site during a disturbance are discussed

Pedagogisk dokumentation på daghem - en väg till ökad delaktighet för vårdnadshavarna

Vårt arbete handlar om pedagogisk dokumentation inom småbarnspedagogiken och dess användning som arbetsredskap för planering och utvärdering av daghemmets verksamhet samt dess roll i främjandet av vårdnadshavarnas delaktighet. Arbetet är ett beställningsarbete av Stiftelsen Sedmigradsky och Barnavårdsföreningen och dess syfte är att ta reda på hur den pedagogiska dokumentationen används inom småbarnspedagogiken och hur den eventuellt bidrar till vårdnadshavarnas delaktighet i daghemmets verksamhet. Våra frågeställningar lyder: ”Hur ser den pedagogiska dokumentationen på Sedmigradskys och Barnavårdsföreningens daghem ut idag och hur utnyttjas den med tanke på utvärdering och planering av deras egen verksamhet?” samt ”Hur kunde man främja vårdnadshavarnas delaktighet inom småbarnspedagogiken och vilken roll, spelar den pedagogiska dokumentationen i detta sammanhang?” Teoridelen i vårt arbete baserar sig på tidigare forskning gjord i Finland, av främst Kati Rintakorpi och Maarit Alasuutari, samt ett socialpedagogiskt perspektiv på delaktighet. Insamlandet av material har vi gjort genom att intervjua personalen på fem av uppdragsgivarnas daghem samt genom en enkätförfrågan bland vårdnadshavarna till barnen på dessa daghem. Svaren vi fått har vi grupperat i temaområden som sedan beskrivits och analyserats. Resultaten visade att pedagogisk dokumentation som begrepp inte är helt främmande för personalen, men att dess användning som arbetsredskap inte ännu är en naturlig del av den dagliga verksamheten. Den största negativt inverkande faktorn som angavs var tidsbrist. Vårdnadshavarna var inte helt medvetna om vilket slags dokumentation som förs på daghemmen, men var i det stora hela nöjda med den dokumentation de fick ta del av och de flesta kände sig delaktiga fastän de inte alltid upplevde sig själv som väldigt aktiva aktörer inom verksamheten som ordnas på daghemmen. Pedagogisk dokumentation har lagts till i den nya planen för småbarnspedagogik och personalen ser detta som något positivt, fast det nämndes på alla daghem att det kommer att ta tid att lära sig dokumentera på ett effektivt och produktivt sätt.This thesis is about pedagogical documentation in Finnish early childhood education and care, and on its effect on parental participation. It is commissioned by the early childhood educational organizations Stiftelsen Sedmigradsky and Barnavårdsföreningen. Our aim is to examine the use of pedagogical documentation, with focus on its use as a tool for plan-ning and evaluation, and to see how pedagogical documentation can help enhance the pa-rental involvement in the daily activities in day care centers. The main questions are: "How is pedagogical documentation used today at the day care centers of Sedmigradsky and Barnavårdsföreningen, and how is it utilized in the aspect of planning and evaluation of the day care centers’ activities?" and "What would increase the degree of parental participation, and how big a part does pedagogical documentation play in this?" The theoretical anchoring is primarily in former Finnish researches on pedagogical documentation and the social pedagogical perspective on participation and social involvement. For this study we interviewed the personnel of 5 different day care centers on their use of pedagogical documenation. We also asked the parents at the same day care centers to fill in a survey with questions about their knowledge and involvement in the practices concerning documentation, planning and evaluation at the day care centers, and their sense of participation in the day care centers’ daily activities. The study has a qualitative perspective and we analyzed and categorized the answers from both personnel and parents and compared their views. Pedagogical documentation has been included in the new plan for early childhood development in Finland as a tool to be used in early childhood education, but our results show that it has not yet reached its full potential; the personnel are still learning the method, they find lack of time being the biggest obstacle for the practice of pedagogical documentation and the parents are not yet fully included in the process of it, although they otherwise seemed pleased with their degree of involvement in the activities of the day care centers

Formulating an Optimization Problem for Minimization of Losses due to Utilities

Utilities, such as steam and cooling water, are often shared between several production areas at industrial sites, and the effects of disturbances in utilities could thus be hard to predict. In addition, production areas could be connected because of the product flow at the site. This paper introduces a simple modeling approach for modeling the relation between utility operation and production. Using this modeling approach, an optimization problem can be formulated with the objective to minimize the economical losses due to disturbances in utilities by controlling the production of all areas at a site. The formulation of the problem is general, and thus the optimization can be performed for any site with similar structure. The results are useful for investigating the impact of plant-wide disturbances in utilities, and can provide decision support for how to control the production at utility disturbances. To enable online advise to operators on how to control the production, the posed optimization problem is solved in receding horizon fashion

Modelling the Value Adding Attributes of Real Estate to the Wealth Maximization of the Firm

Firms develop strategies to help them achieve their primary goal of maximizing the wealth of the shareholders. These strategies should define the supporting role corporate real estate management plays; however current theory and practice do not adequately identify the direct and indirect methods by which corporate real estate management (CREM) adds value to the firm. We develop a model of how real estate adds value to the firm to help fill this void. This model can be then used to develop more precise and complete metrics to measure the value real estate adds to the firm.

A meiotic driver alters sperm form and function in house mice: a possible example of spite

The ability to subvert independent assortment of chromosomes is found in many meiotic drivers, such as the t haplotype in house mice Mus musculus, in which the t-bearing chromosomal homolog is preferentially transmitted to offspring. This is explained by a poison-antidote system, in which developing + and t sperm in testes of + /t males are exposed to ‘poison’ coded by t loci, from which t sperm are protected, allowing t sperm an overwhelming fertilisation advantage in monogamous matings. This system is thought to result in poorly and normally motile sperm subpopulations within + /t sperm, leaving t sperm unharmed. Conversely, we found that the fastest quartile of sperm from + /t males swam more slowly, both forwards and along their travel path, and had reduced straightness and linearity, compared to the fastest quartile of + / + sperm. Moreover, sperm from + /t males had shorter tails and narrower heads than + / + sperm, and these morphological differences covaried with motility differences. Finally, + /t traits did not show evidence of bimodal distributions. We conclude that the t haplotype drive results in lasting damage to the motility of both + and t developing sperm, although previous studies indicate that + must be more harmed than t sperm. This damage to all sperm may explain the low success of + /t males in sperm competition with + / + males, seen in earlier studies. We propose that the harm the t causes to itself could be termed ‘spiteful’, which may also be common to other gamete-harming meiotic drive systems

A General Method for Handling Disturbances on Utilities in the Process Industry

Utilities, such as steam or cooling water, have shown to play an important role within the process industry, since a malfunctioning utility is a plant-wide disturbance that can lead to large revenue losses due to reduced production quantities. This work focuses on identifying disturbances on utilities that give economical consequences. Measures of utility availability and area availability are introduced and used for estimating the ratio of disturbances on utilities. A generic method for handling disturbances on utilities is presented, which could be applied using site models of different level of detail. Some modeling approaches for modeling a site are described and the framework of the general method is demonstrated with a case study example at Perstorp AB, Sweden