Heat Transfer in Plate Heat Exchangers

This study illustrates the different types of plate heat exchangers that are commonly used in various domestic and industrial applications. The main purpose of this paper was to devise a methodology that is capable of calculating optimum number of plates in the design of a plate heat exchanger. To obtain the appropriate number of plates, typically several iterations must be made before a final acceptable design is completed, since plate amount depends on many factors such as, flow velocities, physical properties of the streams, flow channel geometry, allowable pressure drop, plate dimensions, and the gap between the plates. The methodology presented here can be used as a general guide for designing a plate heat exchanger. To investigate the effects of relevant parameters on the thermal-hydraulic design of a plate heat exchanger, several experiments were carried out for single-phase and counter flow arrangement with two brazed plate heat exchangers by varying the flow rates and the inlet temperatures of the fluid streams. The actual heat transfer coefficients obtained based on the experiment were nearly close to the calculated values and to improve the design, a correction factor was introduced. Besides, the effect of flow channel velocity on the pressure drop inside the unit is presented.

Sustainability of palm oil production and opportunities for Finnish technology and know-how transfer

The global demand for palm oil is growing, thus prompting an increase in the global production particularly in Malaysia and Indonesia. Such increasing demand for palm oil is due to palm oil’s relatively cheap price and versatile advantage both in edible and non-edible applications. Along with the increasing demand for palm oil, particularly for the production of biofuel, is a heated debate on its sustainability. Ecological degradation, climate change and social issues are among the main sustainability issues pressing the whole palm oil industry today. Clean Development Mechanism (CDM) projects fulfilling the imperatives of the Kyoto Protocol are starting to gain momentum in Malaysia as reflected by the increasing registration of CDM projects in the palm oil mills. Most CDM projects in palm oil mills are on waste-to-energy, cocomposting, and methane recovery with the latter being the most common. The study on greenhouse gases (GHG) in the milling process points that biogas collection and energy utilisation has the greatest positive effect on GHG balance. On the other hand, empty fruit bunches (EFB) end-use as energy and high energy efficiency of the mill have the least effect on GHG balance of the mill. The range of direct GHG emissions from the palm oil mill is from 2.5 to 27 gCO2e/MJCPO, while the range of GHG emissions with all indirect and avoided emissions included is from -9 to 29 gCO2e/MJCPO. Comparing this GHG balance result with that of the EU RES-Directive suggests a further check on the values and emissions consideration of the latter.

Heat transfer in superheaters of the bubbling fluidized bed boiler conversions

It is often reasonable to convert old boiler to bubbling fluidized bed boiler instead of building a new one. Converted boiler consists of old and new heat surfaces which must be fitted to operate together. Prediction of heat transfer in not so ideal conditions sets challenges for designers. Two converted boilers situated in Poland were studied on the grounds of acceptance tests and further studies. Calculation of boiler process was performed with boiler design program. Main interest was heat transfer in superheaters and factors affecting it. Theory for heat transfer is presented according to information found from literature. Results obtained from experimental studies and calculations have been compared. With correct definitions calculated parameters corresponded well to measured data at boiler maximum design load. However overload situations revealed to be difficult to model at least without considering changes in the combustion process which requires readjustments to the design program input values.

Lanthanide Chelates as Donors in Fluorescence Resonance Energy Transfer: Exciting Prospects for Bioaffinity Assay Detection

Fluorescence resonance energy transfer (FRET) is a non-radiative energy transfer from a fluorescent donor molecule to an appropriate acceptor molecule and a commonly used technique to develop homogeneous assays. If the emission spectrum of the donor overlaps with the excitation spectrum of the acceptor, FRET might occur. As a consequence, the emission of the donor is decreased and the emission of the acceptor (if fluorescent) increased. Furthermore, the distance between the donor and the acceptor needs to be short enough, commonly 10-100 Å. Typically, the close proximity between the donor and the acceptor is achieved via bioaffinity interactions e.g. antibody binding antigen. Large variety of donors and acceptors exist. The selection of the donor/acceptor pair should be done not only based on the requirements of FRET but also the performance expectancies and the objectives of the application should be considered. In this study, the exceptional fluorescence properties of the lanthanide chelates were employed to develop two novel homogeneous immunoassays: a non-competitive hapten (estradiol) assay based on a single binder and a dual-parametric total and free PSA assay. In addition, the quenching efficiencies and energy transfer properties of various donor/acceptor pairs were studied. The applied donors were either europium(III) or terbium(III) chelates; whereas several organic dyes (both fluorescent and quenchers) acted as acceptors. First, it was shown that if the interaction between the donor/acceptor complexes is of high quality (e.g. biotin-streptavidin) the fluorescence of the europium(III) chelate could be quenched rather efficiently. Furthermore, the quenching based homogeneous non-competitive assay for estradiol had significantly better sensitivity (~67 times) than a corresponding homogeneous competitive assay using the same assay components. Second, if the acceptors were chosen to emit at the emission minima of the terbium(III) chelate, several acceptor emissions could be measured simultaneously without significant cross-talk from other acceptors. Based on these results, the appropriate acceptors were chosen for the dual-parameter assay. The developed homogeneous dual-parameter assay was able to measure both total and free PSA simultaneously using a simple mix and measure protocol. Correlation of this assay to a heterogeneous single parameter assay was excellent (above 0.99 for both) when spiked human plasma samples were used. However, due to the interference of the sample material, the obtained concentrations were slightly lower with the homogeneous than the heterogeneous assay, especially for the free PSA. To conclude, in this work two novel immunoassay principles were developed, which both are adaptable to other analytes. However, the hapten assay requires a rather good antibody with low dissociation rate and high affinity; whereas the dual-parameter assay principle is applicable whenever two immunometric complexes can form simultaneously, provided that the requirements of FRET are fulfilled.

A three dimensional study of heat transfer in a supercritical circulating fluidized bed combustor

From the boiler design point of view, it is imperative to know and understand the operation of the boiler. Since comprehensive measurement of a large furnace is impossible, the furnace can be modeled in order to study its behavior and phenomena. This requires the used model to be validated to correspond with the physical furnace behavior. In this thesis, a three dimensional furnace model is validated to match a bituminous coal utilizing, supercritical once-through circulating fluidized bed combustor based on measurement data. The validated model is used for analyzing the furnace heat transfer. Other heat transfer analysis methods are energy balance method based on tube surface temperature measurements and a method based on measured temperature difference between the tube crest and the fin. The latter method was developed in the thesis using Fluent-software. In the theory part, literature is reviewed and the fundamental aspects of circulating fluidized bed are discussed. These aspects are solid particle behavior in fluidization known as hydrodynamics, behavior of fuel and combustion and heat transfer. Fundamental aspects of modeling are also presented.

Role of culture in knowledge transfer and sharing - case ERP implementation

The main objective of this study was to examine how culture influences knowledge transfer and sharing within multicultural ERP project implementation in China. The main interest was to explain how national culture and knowledge are linked by understanding how culture influences knowledge transfer and sharing in a project organization. The other objective of this work was to discuss what Chinese cultural characteristic inhibit and en-hance knowledge sharing in ERP project. The perspective of this study was qualitative and the empirical material was collected from theme interviews among Stora Enso employees. Conclusion of this thesis is that Finns have a very direct style of communication and sharing knowledge whereas Chinese respect face shaving and indirect communication. Another conclusion is that knowledge sharing does not “just happen”, it is needed that project members understand national culture to get all project members commitment to project. In China most important is understand local business processes and understand role of trust and guanxi.

Leaf-Targeted Ferredoxin-NADP+-Oxidoreductase (FNR): Electron Transfer Properties and Thylakoid Association in Arabidopsis thaliana

Photosynthetic reactions are divided in two parts: light-driven electron transfer reactions and carbon fixation reactions. Electron transfer reactions capture solar energy and split water molecules to form reducing energy (NADPH) and energy-carrying molecules (ATP). These end-products are used for fixation of inorganic carbon dioxide into organic sugar molecules. Ferredoxin-NADP⁺ oxidoreductase (FNR) is an enzyme that acts at the branch point between the electron transfer reactions and reductive metabolism by catalyzing reduction of NADP+ at the last step of the electron transfer chain. In this thesis, two isoforms of FNR from A rabidopsis thaliana, FNR1 and FNR2, were characterized using the reverse genetics approach. The fnr1 and fnr2 mutant plants resembled each other in many respects. Downregulation of photosynthesis protected the single fnr mutant plants from excess formation of reactive oxygen species (ROS), even without significant upregulation of antioxidative mechanisms. Adverse growth conditions, however, resulted in phenotypic differences between fnr1 and fnr2. While fnr2 plants showed downregulation of photosynthetic complexes and upregulation of antioxidative mechanisms under low-temperature growth conditions, fnr1 plants had the wild-type phenotype, indicating that FNR2 may have a specific role in redistribution of electrons under unfavorable conditions. The heterozygotic double mutant (fnr1xfnr2) was severely devoid of chloroplastic FNR, which clearly restricted photosynthesis. The fnr1xfnr2 plants used several photoprotective mechanisms to avoid oxidative stress. In wild-type chloroplasts, both FNR isoforms were found from the stroma, the thylakoid membrane, and the inner envelope membrane. In the absence of the FNR1 isoform, FNR2 was found only in the stroma, suggesting that FNR1 and FNR2 form a dimer, by which FNR1 anchors FNR2 to the thylakoid membrane. Structural modeling predicted formation of an FNR dimer in complex with ferredoxin. In this thesis work, Tic62 was found to be the main protein that binds FNR to the thylakoid membrane, where Tic62 and FNR formed high molecular weight complexes. The formation of such complexes was shown to be regulated by the redox state of the chloroplast. The accumulation of Tic62-FNR complexes in darkness and dissociation of complexes from the membranes in light provide evidence that the complexes may have roles unrelated to photosynthesis. This and the high viability of fnr1 mutant plants lacking thylakoid-bound FNR indicate that the stromal pool of FNR is photosynthetically active.

External knowledge transfer mechanisms in service business acquisition

In knowledge-intensive economy an effective knowledge transfer is a part of the firm’s strategy to achieve a competitive advantage in the market. Knowledge transfer related to a variety of mechanisms depends on the nature of knowledge and context. The topic is, however, very little empirical studied and there is a research gap in scientific literature. This study examined and analyzed external knowledge transfer mechanisms in service business and especially in the context of acquisitions. The aim was to find out what kind of mechanisms was used when the buyer began to transfer data e.g. their own agendas and practices to the purchased units. Another major research goal was to identify the critical factors which contributed to knowledge transfer through different mechanisms. The study was conducted as a multiple-case study in a consultative service business company, in its four business units acquired by acquisition, in various parts of the country. The empirical part of the study was carried out as focus group interviews in each unit, and the data were analyzed using qualitative methods. The main findings of this study were firstly the nine different knowledge transfer mechanisms in service business acquisition: acquisition management team as an initiator, unit manager as a translator, formal training, self-directed learning, rooming-in, IT systems implementation, customer relationship management, codified database and ecommunication. The used mechanisms brought up several aspects as giving the face to changing, security of receiving right knowledge and correctly interpreted we-ness atmosphere, and orientation to use more consultative touch with customers. The study pointed out seven critical factors contributed to different mechanisms: absorption, motivation, organizational learning, social interaction, trust, interpretation and time resource. The two last mentioned were new findings compared to previous studies. Each of the mechanisms and the related critical factors contributed in different ways to the activity in different units after the acquisition. The role of knowledge management strategy was the most significant managerial contribution of the study. Phenomenon is not recognized enough although it is strongly linked in knowledge based companies. The recognition would help to develop a better understanding of the business through acquisitions, especially in situations such as where two different knowledge strategies combines in new common company.

Motivational Influences on Transfer: Dimensions and Boundary Conditions

The focus of this dissertation is the motivational influences on transfer in higher education and professional training contexts. To estimate these motivational influences, the dissertation includes seven individual studies that are structured in two parts. Part I, Dimensions, aims at identifying the dimensionality of motivation to transfer and its structural relations with training-related antecedents and outcomes. Part II, Boundary Conditions, aims at testing the predictive validity of motivation theories used in contemporary training research under different study conditions. Data in this dissertation was gathered from multi-item questionnaires, which were analyzed differently in Part I and Part II. Studies in Part I employed exploratory and confirmatory factor analysis, structural equation modeling, partial least squares (PLS) path modeling, and mediation analysis. Studies in Part II used artifact distribution meta-analysis, (nested) subgroup analysis, and weighted least squares (WLS) multiple regression. Results demonstrate that motivation to transfer can be conceptualized as a three-dimensional construct, including autonomous motivation to transfer, controlled motivation to transfer, and intention to transfer, given a theoretical framework informed by expectancy theory, self-determination theory, and the theory of planned behavior. Results also demonstrate that a range of boundary conditions moderates motivational influences on transfer. To test the predictive validity of expectancy theory, social cognitive theory, and the theory of goal orientations under different study settings, a total of 17 boundary conditions were meta-analyzed, including age; assessment criterion; assessment source; attendance policy; collaboration among trainees; computer support; instruction; instrument used to measure motivation; level of education; publication type; social training context; SS/SMC bias; study setting; survey modality; type of knowledge being trained; use of a control group; and work context. Together, the findings cumulated in this thesis support the basic premise that motivation is centrally important for transfer, but that motivational influences need to be understood from a more differentiated perspective than commonly found in the literature, in order to account for several dimensions and boundary conditions. The results of this dissertation across the seven individual studies are reflected in terms of their implications for theory development and their significance for training evaluation and the design of training environments. Limitations and directions to take in future research are discussed.

Frequency-Domain and Wide-Pulse Time-Domain Measurements of Lanthanide Luminescence and Lanthanide-Based Resonance Energy Transfer

Resonance energy transfer (RET) is a non-radiative transfer of the excitation energy from the initially excited luminescent donor to an acceptor. The requirements for the resonance energy transfer are: i) the spectral overlap between the donor emission spectrum and the acceptor absorption spectrum, ii) the close proximity of the donor and the acceptor, and iii) the suitable relative orientations of the donor emission and the acceptor absorption transition dipoles. As a result of the RET process the donor luminescence intensity and the donor lifetime are decreased. If the acceptor is luminescent, a sensitized acceptor emission appears. The rate of RET depends strongly on the donor–acceptor distance (r) and is inversely proportional to r6. The distance dependence of RET is utilized in binding assays. The proximity requirement and the selective detection of the RET-modified emission signal allow homogeneous separation free assays. The term lanthanide-based RET is used when luminescent lanthanide compounds are used as donors. The long luminescence lifetimes, the large Stokes’ shifts and the intense, sharply-spiked emission spectra of the lanthanide donors offer advantages over the conventional organic donor molecules. Both the organic lanthanide chelates and the inorganic up-converting phosphor (UCP) particles have been used as donor labels in the RET based binding assays. In the present work lanthanide luminescence and lanthanide-based resonance energy transfer phenomena were studied. Luminescence lifetime measurements had an essential role in the research. Modular frequency-domain and time-domain luminometers were assembled and used successfully in the lifetime measurements. The frequency-domain luminometer operated in the low frequency domain ( 100 kHz) and utilized a novel dual-phase lock-in detection of the luminescence. One of the studied phenomena was the recently discovered non-overlapping fluorescence resonance energy transfer (nFRET). The studied properties were the distance and temperature dependences of nFRET. The distance dependence was found to deviate from the Förster theory and a clear temperature dependence was observed whereas conventional RET was completely independent of the temperature. Based on the experimental results two thermally activated mechanisms were proposed for the nFRET process. The work with the UCP particles involved the measurement of the luminescence properties of the UCP particles synthesized in our laboratory. The goal of the UCP particle research is to develop UCP donor labels for binding assays. In the present work the effect of the dopant concentrations and the core–shell structure on the total up-conversion luminescence intensity, the red–green emission ratio, and the luminescence lifetime was studied. Also the non-radiative nature of the energy transfer from the UCP particle donors to organic acceptors was demonstrated for the first time in aqueous environment and with a controlled donor–acceptor distance.

Intra-organizational knowledge transfer in a Finnish multinational company

The ability of a multinational company to effectively transfer knowledge from one unit to another can create a great source of competitive advantage and is crucial for long-term success. However, in their attempts to disseminate existent knowledge across national boundaries, organizations encounter several obstacles. Especially challenging is the transfer of tacit knowledge, the most valuable kind, as it is embedded in the minds and the behavior of people. The purpose of this study is to identify the main factors and challenges to be considered in intra-organizational knowledge transfer and consequently develop a framework that could be utilized to improve the process. The research is of qualitative nature and it adopts an exploratory approach. The study was further conducted as an intensive single-case study through studying a Finnish multinational company, and the researcher adopted a role as a participant observant in the research setting. Other data collection methods include semi-structured interviews and an online survey. The research findings show that knowledge transfer is currently challenging within the international sales organization of the case company. The majority of knowledge is currently concentrated in the company headquarters, and it is not always systematically distributed to the regional offices abroad. The main factor affecting knowledge transfer seems to be the organizational culture, which does not support or encourage knowledge sharing. The company is struggling in having a common place for information and employees that lack proper social networks have difficulties accessing relevant knowledge. Some recommended improvement suggestions include the institutionalization of knowledge transfer by turning it into an articulated organizational goal, and the implementation of a reward system that includes soft factors, such as teamwork and knowledge sharing behavior. Furthermore, the organizational culture should be more open and supportive in order to reinforce trust. Individuals in regional offices should be given better support by offering them dedicated mentors and increasing the amount of expatriation. Finally, knowledge should actively be codified and stored in commonly shared platforms where it is easily accessible by all employees.

Transfer of Administrative HR Services to Global Service Center in Poland

Liiketoimintaa tukevien palvelujen etätuotanto edustaa uutta kansainvälistymisen muotoa. Kehittyvien markkinoiden nousu yhdistettynä yritysten arvoketjutoimintojen kansainvälistymiseen on luonut yrityksille kasvavan paineen etsiä parasta sijaintia toiminnoilleen. Monikansalliset yritykset ovat yhä useammin korvanneet paikallisia henkilöstöpalvelujaan siirtymällä globaaliin malliin jaettujen palvelujen tuotannossa. Tämä diplomityö on toteutettu tukeakseen UPM:n henkilöstöhallintoa globaalin palvelukeskuksen perustamisessa Puolaan. Tutkimuksen tavoitteena on laajentaa käsitystä henkilöstöpalvelujen tarjontamallin uudistamiseen johtaneista tekijöistä ja motiiveista. Empiirisen tutkimuksen tärkein tavoite on tukea rekrytoinnin hallinnollisten töiden siirtoa globaaliin palvelukeskukseen palvelun laadun säilyessä vähintään aikaisemmalla tasolla. Tutkimuksen tulokset painottavat strategista näkökulmaa muutokseen. Strategiset syyt UPM:n henkilöstöhallinnon globaalin palvelukeskuksen perustamiselle sisältävät ylikapasiteetin ja päällekkäisten toimintojen vähentämisen eri maissa. Muutos lisää palvelun joustavuutta sekä edesauttaa toiminnan läpinäkyvyyttä, ennustettavuutta ja kustannusten valvontaa. Onnistuneesti toteutetut jaetut palvelut voivat toimia hyvänä lähtökohtana tehokkaiden henkilöstöpalvelujen tuottamiselle.

Fundamentals of heat transfer

Following over 170+ pages and additional appendixes are formed based on content of Course: Fundamentals of Heat Transfer. Mainly this summarizes relevant parts on Book of Fundamentals of Heat and Mass Transfer (Incropera), but also other references introducing the same concepts are included. Student’s point of view has been consideredwith following highlights: (1) Relevant topics are presented in a nutshell to provide fast digestion of principles of heat transfer. (2) Appendixes include terminology dictionary. (3) Totally 22 illustrating examples are connecting theory to practical applications and quantifying heat transfer to understandable forms as: temperatures, heat transfer rates, heat fluxes, resistances and etc. (4) Most important Learning outcomes are presented for each topic separately. The Book, Fundamentals of Heat and Mass Transfer (Incropera), is certainly recommended for those going beyond basic knowledge of heat transfer. Lecture Notes consists of four primary content-wise objectives: (1) Give understanding to physical mechanisms of heat transfer, (2)Present basic concepts and terminology relevant for conduction, convection and radiation (3) Introduce thermal performance analysis methods for steady state and transient conduction systems. (4) Provide fast-to-digest phenomenological understanding required for basic design of thermal models

Cross-cultural knowledge transfer within a multinational company

The ability to share knowledge efficiently is vital in day-to-day operations of multinational companies. Therefore, the tools for the effective knowledge sharing along with the transfer knowledge models are of a primary interest for the companies. Knowledge transfer often involves participants of different cultural background. The purpose of this research is to investigate how the cross-cultural knowledge transfer in a multinational corporation takes place and how the successful knowledge transfer is ensured. The four sub-questions will help to answer the research question. Firstly, the author will try to identify what difficulties might occur while transferring knowledge in a multicultural environment. Secondly, the cultural differences’ impact on cross-cultural communication will be explored. Thirdly, the tools and models for effective tacit knowledge transfer will be covered by the author. Lastly, the methods of assessing if a knowledge transfer was successful or not will be discussed. The focus of this thesis is on knowledge transfer within a multinational setting. A multinational corporation is used as a practical example for this study; namely the Training Centre of the multinational corporation. The study was carried out by using a qualitative research approach. The four employees of the Training Centre were interviewed in order to obtain the answers to the research questions. The complete idea of the data gathering process can be obtained by reading through the first part of the methodology section Furthermore, the matters of transferability, confirmability, trustworthiness and objectivity were discussed in the methodological section. The study indicates that in order to carry out the successful and efficient knowledge transfer several requests have to be met. Mutual motivation, e.g. the motivation of both knowledge sender and knowledge receiver is one of the most important determinants of knowledge transfer. Sufficient and bearable workload for the knowledge senders is important to ensure the quality and involvement of the knowledge sender into knowledge transfer process. Course contents, infrastructure and other matters will be discussed further on in relation of successful knowledge transfer. Influences of cultural differences on knowledge sharing were studied in this thesis. At the end of the empirical study- a model used to transfer knowledge in Training Centre will be presented. The model created proves to be functional and appropriate for transferring knowledge to representatives of different cultures.