Automated formulation of optimisation models for steel beam structures

Over 70% of the total costs of an end product are consequences of decisions that are made during the design process. A search for optimal cross-sections will often have only a marginal effect on the amount of material used if the geometry of a structure is fixed and if the cross-sectional characteristics of its elements are property designed by conventional methods. In recent years, optimalgeometry has become a central area of research in the automated design of structures. It is generally accepted that no single optimisation algorithm is suitable for all engineering design problems. An appropriate algorithm, therefore, mustbe selected individually for each optimisation situation. Modelling is the mosttime consuming phase in the optimisation of steel and metal structures. In thisresearch, the goal was to develop a method and computer program, which reduces the modelling and optimisation time for structural design. The program needed anoptimisation algorithm that is suitable for various engineering design problems. Because Finite Element modelling is commonly used in the design of steel and metal structures, the interaction between a finite element tool and optimisation tool needed a practical solution. The developed method and computer programs were tested with standard optimisation tests and practical design optimisation cases. Three generations of computer programs are developed. The programs combine anoptimisation problem modelling tool and FE-modelling program using three alternate methdos. The modelling and optimisation was demonstrated in the design of a new boom construction and steel structures of flat and ridge roofs. This thesis demonstrates that the most time consuming modelling time is significantly reduced. Modelling errors are reduced and the results are more reliable. A new selection rule for the evolution algorithm, which eliminates the need for constraint weight factors is tested with optimisation cases of the steel structures that include hundreds of constraints. It is seen that the tested algorithm can be used nearly as a black box without parameter settings and penalty factors of the constraints.

Procurement in Project Implementation

Tutkimus keskittyy hankintatoimen kehittämiseen osana laitosprojektien toteutusta. Työ pohjautuu empiiriseltä taustaltaan Pöyry Oyj:n projektiliiketoimintaan ja työn tarkastelunäkökulmaksi onvalittu projektihallinnosta vastaavan yrityksen näkökulma. Tutkimus on hyvin käytännönläheinen ¿ se lähtee hankinnan ja sen seurannan ongelmista ja pyrkii tarjoamaan niihin uudenlaisia ratkaisuja. Pohjimmiltaan tutkimus kuuluu teollisuustalouden piiriin, vaikka tietojärjestelmätieteellä on vahva tukirooli. Työn tavoitteet ja tulokset liittyvät teollisuustaloudelle ominaisesti yrityksen toiminnan kehittämiseen, käytetyt välineet ja ratkaisut puolestaan hyödyntävät tietojärjestelmätieteen antamia mahdollisuuksia. Tutkimuksessa on käytetty konstruktiivista tutkimusotetta, jonka mukaisesti on luotu innovatiivisia konstruktioita ratkaisemaan aitoja reaalimaailman ongelmia ja tätä kautta tuotettu kontribuutioita teollisuustaloudelle. Tavoitteena oli järjestää hankintatoimi ja sen seuranta suurissa laitosprojekteissa tehokkaammin. Tätä varten uudistettiin ensin projektihallinnon ja hankintatoimen toimintaohjeet vastaamaan paremmin nykyajan vaatimuksia. Toimintaohjeiden perusteella ryhdyttiin toteuttamaan hankintaohjelmistoa, joka pystyisi kattamaan kaikki toimintaohjeissa kuvatut piirteet. Lopulta hankintaohjelmisto toi mukanaan uusia piirteitä projektihallintoon ja hankintatoimeen ja nämä sisällytettiin toimintaohjeisiin. Tähän kehitystyöhön ryhdyttiin, jotta laitosprojektien projektihallinto ja hankintatoimi toimisivat paremmin, eli pienemmin kustannuksin tuottaen projekteissa tarvittavat tulokset nopeammin, tarkemmin ja laadukkaammin. Tutkimuksella on kolmenlaisia tuloksia: hankintatoimen parannetut metodit, hankintaohjelmiston pohjana olevat toiminta- ja laskentamallit sekä implementaationa hankintasovellus. Uudistetut projekti- ja hankintaohjeet kuvaavat hankintatoiminnan parannettuja metodeja. Hankintaohjelmistoasuunnitellessa ja kehitettäessä tehdyt kuvaukset sisältävät uusia malleja niin hankintaprosessille kuin hankinnan seuraamiseksi suurissa laitosprojekteissa. Itse ohjelmisto on tuloksena implementaatio, joka perustuu parannettuihin hankintametodeihin ja uusiin toiminta- ja laskentamalleihin. Uudistetut projekti- ja hankintaohjeet ovat olleet käytössä Pöyry Oyj:ssä vuodesta 1991. Vuosien varrella nämä toimintaohjeet ovat auttaneet ja tukeneet satojen laitosprojektientoteutusta ja ylläpitäneet Pöyry Oyj:n kilpailukykyä kansainvälisenä projektitalona. Hankintasovellus puolestaan on ollut käytössä useissa projekteissa ja sen on havaittu pienentävän hankintatoimen suoria työkustannuksia laitosprojekteissa. Sovelluksen katsotaan myös tuovan epäsuoria kustannussäästöjä parempien hankintapäätösten muodossa, mutta näiden säästöjen suuruutta ei pystytä luotettavasti arvioimaan.

Control and Simulation of Batch Crystallization

Concerning process control of batch cooling crystallization the present work focused on the cooling profile and seeding technique. Secondly, the influence of additives on batch-wise precipitation process was investigated. Moreover, a Computational Fluid Dynamics (CFD) model for simulation of controlled batch cooling crystallization was developed. A novel cooling model to control supersaturation level during batch-wise cooling crystallization was introduced. The crystallization kinetics together with operating conditions, i.e. seed loading, cooling rate and batch time, were taken into account in the model. Especially, the supersaturation- and suspension density- dependent secondary nucleation was included in the model. The interaction between the operating conditions and their influence on the control target, i.e. the constant level of supersaturation, were studied with the aid of a numerical solution for the cooling model. Further, the batch cooling crystallization was simulated with the ideal mixing model and CFD model. The moment transformation of the population balance, together with the mass and heat balances, were solved numerically in the simulation. In order to clarify a relationship betweenthe operating conditions and product sizes, a system chart was developed for anideal mixing condition. The utilization of the system chart to determine the appropriate operating condition to meet a required product size was introduced. With CFD simulation, batch crystallization, operated following a specified coolingmode, was studied in the crystallizers having different geometries and scales. The introduced cooling model and simulation results were verified experimentallyfor potassium dihydrogen phosphate (KDP) and the novelties of the proposed control policies were demonstrated using potassium sulfate by comparing with the published results in the literature. The study on the batch-wise precipitation showed that immiscible additives could promote the agglomeration of a derivative of benzoic acid, which facilitated the filterability of the crystal product.

Comprehensive Study of Crystal Growth from Solution

Crystal growth is an essential phase in crystallization kinetics. The rate of crystal growth provides significant information for the design and control of crystallization processes; nevertheless, obtaining accurate growth rate data is still challenging due to a number of factors that prevail in crystal growth. In industrial crystallization, crystals are generally grown from multi-componentand multi-particle solutions under complicated hydrodynamic conditions; thus, it is crucial to increase the general understanding of the growth kinetics in these systems. The aim of this work is to develop a model of the crystal growth rate from solution. An extensive literature review of crystal growth focuses on themodelling of growth kinetics and thermodynamics, and new measuring techniques that have been introduced in the field of crystallization. The growth of a singlecrystal is investigated in binary and ternary systems. The binary system consists of potassium dihydrogen phosphate (KDP, crystallizing solute) and water (solvent), and the ternary system includes KDP, water and an organic admixture. The studied admixtures, urea, ethanol and 1-propanol, are employed at relatively highconcentrations (of up to 5.0 molal). The influence of the admixtures on the solution thermodynamics is studied using the Pitzer activity coefficient model. Theprediction method of the ternary solubility in the studied systems is introduced and verified. The growth rate of the KDP (101) face in the studied systems aremeasured in the growth cell as a function of supersaturation, the admixture concentration, the solution velocity over a crystal and temperature. In addition, the surface morphology of the KDP (101) face is studied using ex situ atomic force microscopy (AFM). The crystal growth rate in the ternary systems is modelled on the basis of the two-step growth model that contains the Maxwell-Stefan (MS) equations and a surface-reaction model. This model is used together with measuredcrystal growth rate data to develop a new method for the evaluation of the model parameters. The validation of the model is justified with experiments. The crystal growth rate in an imperfectly mixed suspension crystallizer is investigatedusing computational fluid dynamics (CFD). A solid-liquid suspension flow that includes multi-sized particles is described by the multi-fluid model as well as by a standard k-epsilon turbulence model and an interface momentum transfer model. The local crystal growth rate is determined from calculated flow information in a diffusion-controlled crystal growth regime. The calculated results are evaluated experimentally.

Seospellettien pienpoltto

This work is a part of Vapos research over mixed pellets. In this work combustion of ten different mixed pellets are examined. This is done by two kinds of tests, burning tests and ash melting tests. First there is a short review how different bio fuels burn and what kind of problems they cause. After this burning characteristics and flue gas calculation methods are acquainted. In test part burning tests and ash melting tests and their results are reported. Lastly conclusions and considerations over further study are done.

Hapettavan BIMODES-mikrobientorjuntamenetelmän vaikutukset paperikoneella

The aim of this study was to examine the effects of oxidising BIMODES microbiological control program on three paper machine process. The chemicals used in BIMODES program are sodium hypochlorite (NaOCl) and bromo-chloro-di-methyl-hydantoin (BCDMH). The literary part of this study discusses the microbiological problems in paper making industry, describes functional mechanisms of oxidants and also introduces the BIMODES- program. In the experimental part the aim was to examine the effects of BIMODES in three different paper machines. The purpose was to find out the effects and changes in wet end chemistry, bacterial counts, in the other additives and also in the sheet defects and holes. The study also examines what are the most important measurements to control BIMODES dosing. In addition the optimal dosing level for each machine was tried to find out. It was found that there is a clear correlation between the total chlorine level and bacterial counts. Changes in the BIMODES dosing level can be measured by redox potential, but the correlation is very poor. BIMODES program doesn’t have straight influence to pH values, but if dosage level is too low the bacterial activity can affect degreasing in the pH value. In this study couldn’t find any consequential effects for the other additives by using BIMODES. In addition the optimal dosing levels were found and by following correct halogen levels it is possible to decrease bacterial levels for very low level.

Aikuisten mediatajun jäljillä

Summary: Tracing media awareness in adults

Kansainvälinen politiikka "käytännöllisten ratkaisujen joukkona" : pragmatistinen tulkinta kansainvälisen politiikan tieteenalan itsekuvasta

English abstract: International relations (IR) as "collection of practical solutions" - pragmatist interpretation of the self-image of the discipline