CFD simulation of complex phenomena containing suspensions and flow throughporous media

There is an increasing reliance on computers to solve complex engineering problems. This is because computers, in addition to supporting the development and implementation of adequate and clear models, can especially minimize the financial support required. The ability of computers to perform complex calculations at high speed has enabled the creation of highly complex systems to model real-world phenomena. The complexity of the fluid dynamics problem makes it difficult or impossible to solve equations of an object in a flow exactly. Approximate solutions can be obtained by construction and measurement of prototypes placed in a flow, or by use of a numerical simulation. Since usage of prototypes can be prohibitively time-consuming and expensive, many have turned to simulations to provide insight during the engineering process. In this case the simulation setup and parameters can be altered much more easily than one could with a real-world experiment. The objective of this research work is to develop numerical models for different suspensions (fiber suspensions, blood flow through microvessels and branching geometries, and magnetic fluids), and also fluid flow through porous media. The models will have merit as a scientific tool and will also have practical application in industries. Most of the numerical simulations were done by the commercial software, Fluent, and user defined functions were added to apply a multiscale method and magnetic field. The results from simulation of fiber suspension can elucidate the physics behind the break up of a fiber floc, opening the possibility for developing a meaningful numerical model of the fiber flow. The simulation of blood movement from an arteriole through a venule via a capillary showed that the model based on VOF can successfully predict the deformation and flow of RBCs in an arteriole. Furthermore, the result corresponds to the experimental observation illustrates that the RBC is deformed during the movement. The concluding remarks presented, provide a correct methodology and a mathematical and numerical framework for the simulation of blood flows in branching. Analysis of ferrofluids simulations indicate that the magnetic Soret effect can be even higher than the conventional one and its strength depends on the strength of magnetic field, confirmed experimentally by Völker and Odenbach. It was also shown that when a magnetic field is perpendicular to the temperature gradient, there will be additional increase in the heat transfer compared to the cases where the magnetic field is parallel to the temperature gradient. In addition, the statistical evaluation (Taguchi technique) on magnetic fluids showed that the temperature and initial concentration of the magnetic phase exert the maximum and minimum contribution to the thermodiffusion, respectively. In the simulation of flow through porous media, dimensionless pressure drop was studied at different Reynolds numbers, based on pore permeability and interstitial fluid velocity. The obtained results agreed well with the correlation of Macdonald et al. (1979) for the range of actual flow Reynolds studied. Furthermore, calculated results for the dispersion coefficients in the cylinder geometry were found to be in agreement with those of Seymour and Callaghan.

Supporting Solution Business with an Integrated Enterprise System

Some of the world’s leading companies now compete by providing integrated solutions to identify and solve each customer’s business problem by providing services to design, integrate, operate and finance a product or system during its life cycle. At the same time, because of the requirements of new global economy, companies are implementing new integrated ERP systems. The objective of this thesis was to define how solution offering can be implemented in the integrated ERP system so that it is possible to sell, deliver and maintain solution offering with the new enterprise applications. The research was conducted as a qualitative case study research consisting of literature review, theme-interviews and an analysis phase. For a start this study introduces new insight for combining solution business, offering modeling and modern ERP system theories. The results of this research illustrate the limitations of an integrated ERP system to support solution business and show the need to develop a commercial product model in order to improve the combination of solution offering and IT systems.

Supporting the Management of the Knowledge Flow from the Customers in CRM through a VCE

Knowledge flow from the customers is an important resource for a company and therefore it should engage its customers in knowledge co-creation. Through providing a virtual customer environment (VCE) as knowledge creation and sharing platform a company can obtain this type of knowledge, which is important for strategic purposes. In the VCE the members of the virtual customer community (VCC) create and share knowledge individually and collectively in diverse roles, utilizing many interaction facilities. Creating a functional VCE is not either easy or quick task and a company needs to analyze various issues carefully. Providing such a VCE in which customers want to share their experiences and insights is however worth of considering, since it brings many benefits for the company. In this research the main benefit is stated as the supportative role of the VCE in the better management of the knowledge flow from the customers.

A Practical Micro Mechanical Model Based Local Approach Methodology for the Analysis of Ductile Fracture of Welded T-Joints

This thesis concentrates on developing a practical local approach methodology based on micro mechanical models for the analysis of ductile fracture of welded joints. Two major problems involved in the local approach, namely the dilational constitutive relation reflecting the softening behaviour of material, and the failure criterion associated with the constitutive equation, have been studied in detail. Firstly, considerable efforts were made on the numerical integration and computer implementation for the non trivial dilational Gurson Tvergaard model. Considering the weaknesses of the widely used Euler forward integration algorithms, a family of generalized mid point algorithms is proposed for the Gurson Tvergaard model. Correspondingly, based on the decomposition of stresses into hydrostatic and deviatoric parts, an explicit seven parameter expression for the consistent tangent moduli of the algorithms is presented. This explicit formula avoids any matrix inversion during numerical iteration and thus greatly facilitates the computer implementation of the algorithms and increase the efficiency of the code. The accuracy of the proposed algorithms and other conventional algorithms has been assessed in a systematic manner in order to highlight the best algorithm for this study. The accurate and efficient performance of present finite element implementation of the proposed algorithms has been demonstrated by various numerical examples. It has been found that the true mid point algorithm (a = 0.5) is the most accurate one when the deviatoric strain increment is radial to the yield surface and it is very important to use the consistent tangent moduli in the Newton iteration procedure. Secondly, an assessment of the consistency of current local failure criteria for ductile fracture, the critical void growth criterion, the constant critical void volume fraction criterion and Thomason's plastic limit load failure criterion, has been made. Significant differences in the predictions of ductility by the three criteria were found. By assuming the void grows spherically and using the void volume fraction from the Gurson Tvergaard model to calculate the current void matrix geometry, Thomason's failure criterion has been modified and a new failure criterion for the Gurson Tvergaard model is presented. Comparison with Koplik and Needleman's finite element results shows that the new failure criterion is fairly accurate indeed. A novel feature of the new failure criterion is that a mechanism for void coalescence is incorporated into the constitutive model. Hence the material failure is a natural result of the development of macroscopic plastic flow and the microscopic internal necking mechanism. By the new failure criterion, the critical void volume fraction is not a material constant and the initial void volume fraction and/or void nucleation parameters essentially control the material failure. This feature is very desirable and makes the numerical calibration of void nucleation parameters(s) possible and physically sound. Thirdly, a local approach methodology based on the above two major contributions has been built up in ABAQUS via the user material subroutine UMAT and applied to welded T joints. By using the void nucleation parameters calibrated from simple smooth and notched specimens, it was found that the fracture behaviour of the welded T joints can be well predicted using present methodology. This application has shown how the damage parameters of both base material and heat affected zone (HAZ) material can be obtained in a step by step manner and how useful and capable the local approach methodology is in the analysis of fracture behaviour and crack development as well as structural integrity assessment of practical problems where non homogeneous materials are involved. Finally, a procedure for the possible engineering application of the present methodology is suggested and discussed.

Supporting older people’s independent living at home through social and health care collaboration

Tässä tutkimuksessa tarkasteltiin ikäihmisten kotona asumista sosiaali- ja terveydenhuollon yhteistyön näkökulmasta. Tutkimuksen tarkoituksena oli lisätä ymmärrystä iäkkäiden kotihoidon asiakkaiden voimavaroista arjesta selviytymisen näkökulmasta, ja tutkia miten asiakkaiden hoito sosiaali- ja terveydenhuollon yhteistyönä toteutuu. Tutkimus oli poikkileikkaustutkimus, jossa sovellettiin kuvailevaa ja vertailevaa tutkimusasetelmaa. Tutkimusaineisto kerättiin yhden länsisuomalaisen kunnan kotihoidon asiakkailta (≥65 v.) ja heitä hoitavilta ammattihenkilöiltä. Kotihoidon 21 iäkästä asiakasta kuvasivat omia voimavarojaan arjesta selviytymisen näkökulmasta sekä kokemuksiaan hoidon toteutumisesta ammattihenkilöiden yhteistyönä. Aineisto kerättiin avoimella haastattelulla ja analysoitiin sisällön analyysillä. Lisäksi 25 kotihoidon ammattihenkilöä: 13 kotipalvelun työntekijää, 11 kotisairaanhoitajaa ja lääkäri kuvasivat kokemuksiaan iäkkään asiakkaan hoidon toteutumisesta ammattihenkilöiden yhteistyönä. Aineisto kerättiin fokusryhmähaastattelulla ja analysoitiin sisällön analyysillä. Näiden tulosten sekä aikaisemman kirjallisuuden perusteella laadittiin strukturoitu kyselylomake, jolla analysoitiin ja vertailtiin asiakkaiden ja ammattihenkilöiden näkemyksiä siitä, miten asiakkaiden hoito sosiaali- ja terveydenhuollon yhteistyönä toteutui. Esitestausten jälkeen kyselylomake lähetettiin 200 kotihoidon asiakkaalle ja 570 heitä hoitavalle kotihoidon työntekijälle: 485 kotipalvelun työntekijälle, 81 kotisairaanhoitajalle ja 4 lääkärille. Kyselyyn vastasi 120 asiakasta (60 %) ja 370 ammattihenkilöä (65 %). Ryhmien välisten erojen tarkastelussa käytettiin ristiintaulukointia, Pearsonin khin neliötestiä ja Fisherin tarkan todennäköisyyden testiä. Iäkkäiden asiakkaiden kuvauksissa voimavarat muodostuivat elämänhallinnan tunteesta ja toimintatahdon säilymisestä. Asiakkaat ammensivat arkeen voimaa harrastuksista ja sosiaalisesta verkostosta, mutta ulkopuolisten asettamat elämisen ehdot, terveydentilan heikkeneminen sekä yksinäisyys asettivat ikäihmisen ja hänen voimavaransa suurten haasteiden eteen. Tulokset osoittivat, että ammattihenkilöiden toiminta oli osittain ristiriidassa ikäihmisten omien odotusten kanssa, eikä se kaikilta osin tukenut asiakkaiden omia voimavaroja. Ammattihenkilöt tekivät hoitoon liittyviä päätöksiä ja toimintoja asiakkaiden puolesta, vaikka asiakkaille itselleen oli tärkeää elämänhallinnan tunne ja toimintatahdon säilyminen. Asiakkaiden voimavarojen tukemista moniammatillisena yhteistyönä vaikeuttivat ammattihenkilöiden vaikeus tunnistaa asiakkaiden omia voimavaroja sekä niitä uhkaavia tekijöitä, tiedon kulun ongelmat, tavoitteeton ja epäyhtenäinen tapa toimia sekä ammattihenkilöiden vastakkain asettuvat näkemyserot ja toimintatavat. Asiakkaiden ja ammattihenkilöiden näkemykset toteutetusta hoidosta erosivat toisistaan tilastollisesti merkitsevästi (p<0.05). Asiakkaat arvioivat sekä itsenäiseen toimintaan tukemisen että fyysisen, psyykkisen ja sosiaalisen tuen toteutuneen työntekijöitä huonommin. Yhteistyön kehittämishaasteita kotihoidossa ovat asiakkaan oman elämänsä asiantuntijuuden vahvistaminen, toimintakulttuurin muuttaminen asiakaslähtöiseksi tavoitteelliseksi toiminnaksi, ammattihenkilöiden roolien ja vastuun selkiyttäminen sekä tiedon kulun menetelmien kehittäminen. Tutkimus vahvistaa gerontologisen hoitotieteen tietoperustaa ja tuottaa uutta tietoa, jota voidaan soveltaa sosiaali- ja terveysalan koulutuksessa ja johtamisessa

Groupware and Workflow Tools - A Case study of SAP Business Workflow Supporting System Integration in a Global Telecommunication Company

Workflow management systems aim at the controlled execution of complex application processes in distributed and heterogeneous environments. These systems will shape the structure of information systems in business and non-business environments. E business and system integration is a fertile soil for WF and groupware tools. This thesis aims to study WF and groupware tools in order to gather in house knowledge of WF to better utilize WF solutions in future, and to focus on SAP Business Workflow in order to find a global solution for Application Link Enabling support for system integration. Piloting this solution in Nokia collects the experience of SAP R/3 WF tool for other development projects in future. The literary part of this study will guide to the world of business process automation providing a general description of the history, use and potentials of WF & groupware software. The empirical part of this study begins with the background of the case study describing the IT environment initiating the case by introducing SAP R/3 in Nokia, the communication technique in use and WF tool. Case study is focused in one solution with SAP Business Workflow. This study provides a concept to monitor communication between ERP systems and to increase the quality of system integration. Case study describes a way create support model for ALE/EDI interfaces. Support model includes monitoring organization and the workflow processes to solve the most common IDoc related errors.

Designing features for supporting social interactions in online communities

This Master's thesis studies the development of interaction and socialization in online communities. A large number of online communities fade away even before they really get started. In many occasions the reason is that the community does not give anything new, or even if they do, the delivery does not satisfy the users. In this thesis guidelines were developed to help to see important things, which might be forgotten when developing an online community. The thesis goes through the characteristic of an online community and human behaviour related to them and also compares behaviour in the Internet and real life. In addition, usability is an important part of the online communities and thus it is also covered in this thesis. As a result of this thesis an 8-step guideline was developed to ease the design of an online community. Guidelines were also applied to two real life cases which are described as one part of this work.

Machine Learning and Clinical Text. Supporting Health Information Flow

Fluent health information flow is critical for clinical decision-making. However, a considerable part of this information is free-form text and inabilities to utilize it create risks to patient safety and cost-­effective hospital administration. Methods for automated processing of clinical text are emerging. The aim in this doctoral dissertation is to study machine learning and clinical text in order to support health information flow.First, by analyzing the content of authentic patient records, the aim is to specify clinical needs in order to guide the development of machine learning applications.The contributions are a model of the ideal information flow,a model of the problems and challenges in reality, and a road map for the technology development. Second, by developing applications for practical cases,the aim is to concretize ways to support health information flow. Altogether five machine learning applications for three practical cases are described: The first two applications are binary classification and regression related to the practical case of topic labeling and relevance ranking.The third and fourth application are supervised and unsupervised multi-class classification for the practical case of topic segmentation and labeling.These four applications are tested with Finnish intensive care patient records.The fifth application is multi-label classification for the practical task of diagnosis coding. It is tested with English radiology reports.The performance of all these applications is promising. Third, the aim is to study how the quality of machine learning applications can be reliably evaluated.The associations between performance evaluation measures and methods are addressed,and a new hold-out method is introduced.This method contributes not only to processing time but also to the evaluation diversity and quality. The main conclusion is that developing machine learning applications for text requires interdisciplinary, international collaboration. Practical cases are very different, and hence the development must begin from genuine user needs and domain expertise. The technological expertise must cover linguistics,machine learning, and information systems. Finally, the methods must be evaluated both statistically and through authentic user-feedback.

Calculation of the carbon footprint of Finnish barley products - methodology and possible applications

The purpose of this thesis was to define how product carbon footprint analysis and its results can be used in company's internal development as well as in customer and interest group guidance, and how these factors are related to corporate social responsibility. From-cradle-to-gate carbon footprint was calculated for three products; Torino Whole grain barley, Torino Pearl barley, and Elovena Barley grit & oat bran, all of them made of Finnish barley. The carbon footprint of the Elovena product was used to determine carbon footprints for industrial kitchen cooked porridge portions. The basic calculation data was collected from several sources. Most of the data originated from Raisio Group's contractual farmers and Raisio Group's cultivation, processing and packaging specialists. Data from national and European literature and database sources was also used. The electricity consumption for porridge portions' carbon footprint calculations was determined with practical measurements. The carbon footprint calculations were conducted according to the ISO 14044 standard, and the PAS 2050 guide was also applied. A consequential functional unit was applied in porridge portions' carbon footprint calculations. Most of the emissions from barley products' life cycle originate from primary production. The nitrous oxide emissions from cultivated soil and the use and production of nitrogenous fertilisers contribute over 50% of products' carbon footprint. Torino Pearl barley has the highest carbon footprint due to the lowest processing output. The reductions in products' carbon footprint can be achieved with developments in cultivation and grain processing. The carbon footprint of porridge portion can be reduced by using domestically produced plant-based ingredients and by making the best possible use of the kettle. Carbon footprint calculation can be used to determine possible improvement points related to corporate environmental responsibility. Several improvement actions are related to economical and social responsibility through better raw material utilization and expense reductions.

Choice of Business Process Modeling Methodology - Case Northern Dimension Research Centre (NORDI) in Lappeenranta University of Technology

The main outcome of the master thesis is innovative solution, which can support a choice of business process modeling methodology. Potential users of this tool are people with background in business process modeling and possibilities to collect required information about organization’s business processes. Master thesis states the importance of business process modeling in implementation of strategic goals of organization. It is made by revealing the place of the concept in Business Process Management (BPM) and its particular case Business Process Reengineering (BPR). In order to support the theoretical outcomes of the thesis a case study of Northern Dimension Research Centre (NORDI) in Lappeenranta University of Technology was conducted. On its example several solutions are shown: how to apply business process modeling methodologies in practice; in which way business process models can be useful for BPM and BPR initiatives; how to apply proposed innovative solution for a choice of business process modeling methodology.

The Plastic Capacity of Boiler Supporting Headers

The goal of this thesis was to make a dimensioning tool to determine the plastic capacity of the boiler supporting header. The capacity of the header is traditionally determined by using FE-method during the project phase. By using the dimensioning tool the goal is to ensure the capacity already in the proposal phase. The study began by analyzing the headers of the ongoing projects by using FE-method. For the analytical solution a plain header was analyzed without the effects of branches or lug. The calibration of parameters in the analytical solution was made using these results. In the analytical solution the plastic capacity of the plastic hinges in the header was defined. The stresses caused by the internal pressure as well as the normal and shear forces caused by the external loading reduced the plastic moment. The final capacity was determined by using the principle of virtual work. The weakening effect of the branches was taken into account by using pressure areas. Also the capacity of the punching shear was defined. The results from the FE-analyses and the analytical solution correlate with each other. The results from the analytical solution are conservative but give correct enough results when considering the accuracy of the used method.

Methodology for an AMB system commissioning

This master’s thesis is focused on the active magnetic bearings system commissioning. The scope of the work is to test the existent procedures with old and new prototypes of an AMB system and additionally automate necessary steps instead of their hand tuning, because determination of rotor clearances and finding effective rotor-origins are time consuming and error prone. The final goal is to get a documented and mostly automated step by step methodology for end efficient system’s commissioning.