Los electrodos de pasta de carbono en el estudio electroquímico de minerales metálicos

This paper shows the applicability of the carbon paste electrode-mineral (CPE-mineral) to study the dissolution mechanisms of minerals in powder form and in flotation concentrates. A potentiodynamic strategy to find the dissolution mechanism of galena (PbS) is presented. In this way, minerals less studied such as orpiment (As2S3) and realgar (As2S2) are investigated. The electrochemical activity of a more complicated mineral such as sphalerite (ZnS), containing 12.3 and 0.43% of iron in solid solution, is discussed. The mechanism of a complex zinc concentrate (containing 63.4% ZnS, 20.1% FeS2, 5% CuFeS2, 0.33% PbS, 0.45% Cu12Sb4S13 and 0.4% FeAsS) is described. Finally, an electrochemical method for the detection of the different leachable and refractory silver phases (contained in two mineral concentrates) is presented. This paper reviews the power of the use of CPE-mineral coupled to electrochemical techniques in hydrometallurgy.

Competitive flexibility in systems supplier companies in mechanical engineering industry

Systems suppliers are focal actors in mechanical engineering supply chains, in between general contractors and component suppliers. This research concentrates on the systems suppliers’ competitive flexibility, as a competitive advantage that the systems supplier gains from independence from the competitive forces of the market. The aim is to study the roles that power, dependence relations, social capital, and interorganizational learning have on the competitive flexibility. Research on this particular theme is scarce thus far. The research method applied here is the inductive multiple case study. Interviews from four case companies were used as main source of the qualitative data. The literature review presents previous literature on subcontracting, supply chain flexibility, supply chain relationships, social capital and interorganizational learning. The result of this study are seven propositions and consequently a model on the effects that the dominance of sales of few customers, power of competitors, significance of the manufactured system in the end product, professionalism in procurement and the significance of brand products in the business have on the competitive flexibility. These relationships are moderated by either social capital or interorganizational learning. The main results obtained from this study revolve around social capital and interorganizational learning, which have beneficial effects on systems suppliers’ competitive flexibility, by moderating the effects of other constructs of the model. Further research on this topic should include quantitative research to provide the extent to which the results can be reliably generalized. Also each construct of the model gives possible focus for more thorough research.

The Effect of Operational Disturbances on Reliability and Operation Time Distribution of NCmachine Tools in FMS

This thesis concentrates on studying the operational disturbance behavior of machine tools integrated into FMS. Operational disturbances are short term failures of machine tools which are especially disruptive to unattended or unmanned operation of FMS. The main objective was to examine the effect of operational disturbances on reliability and operation time distribution for machine tools. The theoretical part of the thesis covers the fimdamentals of FMS relating to the subject of this study. The concept of FMS, its benefits and operator's role in FMS operation are reviewed. The importance of reliability is presented. The terms describing the operation time of machine tools are formed by adopting standards and references. The concept of failure and indicators describing reliability and operational performance for machine tools in FMSs are presented. The empirical part of the thesis describes the research methodology which is a combination of automated (ADC) and manual data collection. By using this methodology it is possible to have a complete view of the operation time distribution for studied machine tools. Data collection was carried out in four FMSs consisting of a total of 17 machine tools. Each FMS's basic features and the signals of ADC are described. The indicators describing the reliability and operation time distribution of machine tools were calculated according to collected data. The results showed that operational disturbances have a significant influence on machine tool reliability and operational performance. On average, an operational disturbance occurs every 8,6 hours of operation time and has a down time of 0,53 hours. Operational disturbances cause a 9,4% loss in operation time which is twice the amount of losses caused by technical failures (4,3%). Operational disturbances have a decreasing influence on the utilization rate. A poor operational disturbance behavior decreases the utilization rate. It was found that the features of a part family to be machined and the method technology related to it are defining the operational disturbance behavior of the machine tool. Main causes for operational disturbances were related to material quality variations, tool maintenance, NC program errors, ATC and machine tool control. Operator's role was emphasized. It was found that failure recording activity of the operators correlates with the utilization rate. The more precisely the operators record the failure, the higher is the utilization rate. Also the FMS organizations which record failures more precisely have fewer operational disturbances.

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.

Yritysjärjestelyiden vaikutus lyhyen aikavälin osaketuottoihin ja pitkän aikavälin kannattavuuteen Suomen markkinoilla

Tutkimuksen tavoitteena on selvittää yritysjärjestelyiden vaikutuksia Suomen markkinoilla, sekä tutkia onko yritysjärjestelyiden eroavaisuuksilla vaikutusta menestymiseen. Yritysjärjestelyt ryhmitellään maksutavan, koon, kansainvälisyyden ja markkina-arvo/kirja-arvon perusteella. Tutkimuksen aineisto koostuu 31 yritysjärjestelystä, joissa ainakin toinen osapuoli on ilmoitushetkellä ollut listattuna Helsingin pörssiin. Tutkimukseen valitut yritysjärjestelyt ovat tapahtuneet vuosien 1999-2007 välillä. Tutkimus suoritetaan kahdella eri menetelmällä: markkinaperusteisia tuottoja ja yritysten taloudellista informaatiota analysoimalla. Markkinaperusteisia tuottoja tutkitaan epänormaaleiden tuottojen avulla. Taloudelliseen informaatioon perustuvaa kannattavuutta tutkitaan kassavirran ja operatiivisen tuloksen avulla, jotka suhteutetaan yritysten markkina-arvoon ja liikevaihtoon. Empiiristen tulosten mukaan yritysjärjestelyt tuottavat ostettavan yrityksen osakkeenomistajille epänormaaleita tuottoja ja ostavan yrityksen osakkeenomistajille nollatuottoja. Tulokset ovat samankaltaisia kuin kansainvälisellä aineistolla aiemmin saadut. Taloudelliseen informaatioon perustuvat tulokset ovat ristiriitaisia mutta niistä on havaittavissa heikohko menestyminen yhdistymisen jälkeen.

Logistiikan kehittäminen tehdasalueella

Logistiikan kehittäminen on nykypäivänä tärkeä tekijä yrityksen kilpailukyvyn parantamiseksi. Huonon taloustilanteen takia kustannussäästöt sekä logistisen toimitusketjun tehostaminen ovat nyt entistä tärkeämmässä asemassa. Tämän diplomityön päätavoitteena on tehdasalueen logistiikan kehittämisen avulla saavuttaa säästöjä Sulzer Pumps Finland Oy:n Karhulassa sijaitsevien yksiköiden logistiikka-kustannuksissa. Logistiikkatoimintoja on vuosien saatossa vähitellen ulkoistettu, joten tutkimus keskittyy pääosin ulkoistettujen logistiikkapalvelujen kehittämiseen. Nykytilan selvittäminen suoritettiin ensin haastatteluiden ja seurannan avulla. Selvityksen tuloksena havaittiin palveluntoimittajien toiminnoissa esiintyvän päällekkäisyyksiä ja tehottomuutta, joista aiheutuu yritykselle ylimääräisiä kustannuksia. Logistiikan kehittämisehdotuksia käsitellään tässä tutkimuksessa tehokkuuden lisäämisen, ylimääräisten työvaiheiden vähentämisen sekä roolijaon selkeyttämisen näkökulmista. Työn keskeisenä tuloksena todettiin myös, että vaiheittaisen ulkoistamisen myötä on menetetty ulkoistetun logistiikkapalvelun hallinta. Hallinnan palauttamisen keinoina käsitellään raportoinnin ja tiedonkulun lisäämistä, sopimuksellisia ja veloitusperusteellisia näkökulmia sekä palvelu- ja kustannustason mittaamiseen soveltuvien mittareiden kehittämistä.

Change of Electricity Distribution Industry: Drivers and Opening Business Opportunities

As a result of the recent regulatory amendments and other development trends in the electricity distribution business, the sector is currently witnessing radical restructuring that will eventually impact the business logics of the sector. This report represents upcoming changes in the electricity distribution industry and concentrates on the factors that are expected to be the most fundamental ones. Electricity network companies nowadays struggle with legislative and regulatory requirements that focus on both the operational efficiency and the reliability of electricity distribution networks. The forces that have an impact on the distribution network companies can be put into three main categories that define the transformation at a general level. Those are: (1) a requirement for a more functional marketplace for energy, (2) environmental aspects (combating climate change etc.), and (3) a strongly emphasized requirement for the security of energy supply. The first point arises from the legislators’ attempt to increase competition in electricity retail markets, the second one concerns both environmental protection and human safety issues, and the third one indicates societies’ reduced willingness to accept interruptions in electricity supply. In the future, regulation of electricity distribution business may lower the threshold for building more weather-resistant networks, which in turn means increased underground cabling. This development pattern is reinforced by tightening safety and environmental regulations that ultimately make the overhead lines expensive to build and maintain. The changes will require new approaches particularly in network planning, construction, and maintenance. The concept for planning, constructing, and maintaining cable networks is necessary because the interdependencies between network operations are strong, in other words, the nature of the operation requires a linkage to other operations.

Packet backbone design differences between commercial network and Container Trial System of LTE/SAE

The mobile networks of earlier and current generations, or 2G and 3G networks, provide users voice and packet services with higher transmission rates and good quality over the same core network. When developing the next generation of mobile networks the current quality of services needs to be maintained. This thesis concentrates on the next generation mobile network, especially on the evolution of the packet network part. The new mobile network has requirements for the common packet backbone network, Mobile Packet Backbone Network, which is additionally discussed in this study. The next generation mobile network, called LTE/SAE, is currently under testing. The test system is called Container Trial System. It is a mini sized LTE/SAE site. The LTE/SAE is studied in this thesis concentrating on the evolved packet core, the SAE part of the composition. The empirical part of the study compares the LTE/SAE Container Trial System and commercial network designs and additionally produces documentation for internal personnel and customers. The research is performed by comparing the documentations and specifications of both the Container Trial System and commercial network. Since the LTE commercial network is not yet constructed, the comparison is done theoretically. The purpose is furthermore to find out if there are any design issues that could be done differently in the next version of the Container Trial System.

ContinuousMultimodal Global Optimization with Differential Evolution-Based Methods

Metaheuristic methods have become increasingly popular approaches in solving global optimization problems. From a practical viewpoint, it is often desirable to perform multimodal optimization which, enables the search of more than one optimal solution to the task at hand. Population-based metaheuristic methods offer a natural basis for multimodal optimization. The topic has received increasing interest especially in the evolutionary computation community. Several niching approaches have been suggested to allow multimodal optimization using evolutionary algorithms. Most global optimization approaches, including metaheuristics, contain global and local search phases. The requirement to locate several optima sets additional requirements for the design of algorithms to be effective in both respects in the context of multimodal optimization. In this thesis, several different multimodal optimization algorithms are studied in regard to how their implementation in the global and local search phases affect their performance in different problems. The study concentrates especially on variations of the Differential Evolution algorithm and their capabilities in multimodal optimization. To separate the global and local search search phases, three multimodal optimization algorithms are proposed, two of which hybridize the Differential Evolution with a local search method. As the theoretical background behind the operation of metaheuristics is not generally thoroughly understood, the research relies heavily on experimental studies in finding out the properties of different approaches. To achieve reliable experimental information, the experimental environment must be carefully chosen to contain appropriate and adequately varying problems. The available selection of multimodal test problems is, however, rather limited, and no general framework exists. As a part of this thesis, such a framework for generating tunable test functions for evaluating different methods of multimodal optimization experimentally is provided and used for testing the algorithms. The results demonstrate that an efficient local phase is essential for creating efficient multimodal optimization algorithms. Adding a suitable global phase has the potential to boost the performance significantly, but the weak local phase may invalidate the advantages gained from the global phase.

Kokonaiskustannusajattelu hankintastrategian muodostamisen tukena

Työn tavoitteena on syventää ymmärrystä siitä, miten hankintatoimi voi hyödyntää kokonaiskustannusajattelua hankintastrategiaan liittyvien päätösten, kuten toimittajamäärän ja toimittajavalinnan tukena. Työn tarkoituksena on kehittää case- yrityksen kaapelituoteryhmälle kokonaiskustannusmalli ja antaa suosituksia tämän tuoteryhmän hankintaan soveltuvasta hankintastrategiasta. Tutkimus on luonteeltaan laadullinen ja se jakaantuu teoreettiseen ja empiiriseen osaan. Teoreettinen tutkimus perustuu kirjallisuustutkimukseen kokonaiskustannusajattelun, hankintastrategian osatekijöiden ja hankintastrategian muodostamisen teorioista. Empiirinen tutkimus on metodologialtaan kuvaileva ja vertaileva tapaustutkimus, jossa keskitytään kaapeleiden hankintaan. Empiirisessä osassa selvitetään kaapeleiden hankinnan nykytila, muodostetaan kokonaiskustannusmalli kaapeleille ja määritetään tärkeimmät kaapeleiden hankinnan kustannuksia aiheuttavat tekijät sekä muut hankintastrategian muodostamisessa huomioitavat tekijät. Hankintatoimi voi hyödyntää kokonaiskustannusajattelua useiden eri hankintapäätösten tukena. Tutkimuksessa kokonaiskustannusanalyysin avulla vertailtiin valmistajien ja tukkuliikkeiden välisiä kokonaiskustannuksia. Analyysin pohjalta valmistajien todettiin olevan kokonaiskustannuksiltaan huomattavasti edullisempia kaapelitoimittajia kuin tukkuliikkeet. Kokonaiskustannusanalyysi auttoi myös osoittamaan, että tukkuliikkeiden käyttö nykyisellä toimintamallilla on kannattamatonta ja, ettei tukkuliikkeiden palveluja hyödynnetä parhaalla mahdollisella tavalla.

Database of the Amazon aromatic plants and their essential oils

The aromatic flora of the Amazon has been inventoried for 30 years. In this sense, were made over 500 field trips to collect over 2500 plants and to obtain more than 2000 essential oils and aroma concentrates, all of them submitted to GC and GC-MS. This work led to the creation of a database for the aromatic plants of the Amazon, which catalogs general information about 1250 specimens. The database has allowed the publication of the chemical composition of the oils and aromas of more than 350 species, associated with a larger number of chemical types. The essential oils of many species offer optimum conditions for economic exploitation and use in national and international market of fragrances, cosmetics, agricultural and household pesticides.

Obtenção e avaliação de concentrados proteicos de corvina (Micropogonias furnieri) processados por extração química

The objective of this study was to obtain and evaluate physicochemical and functional properties of protein concentrates from Micropogonias furnieri produced by pH shifting process, using alkaline and acid solubilization followed by isoelectric precipitation of muscle proteins. The concentrates showed high protein content and the maxim solubility for the minced (96.5%), for the alkaline (97.5%) and acid (93.7%) extraction was obtained at pH 11.0. The water holding capacity of the alkaline concentrate resulted in a value same or superior to water holding capacity of the acid concentrate in all investigated values of pH. The oil holding capacity of alkaline and acid concentrates showed no significant difference between the studied processes.

Autokaupan markkinatilannemuutoksen vaikutukset autoliikkeiden hankintaprosesseihin

The thesis concentrates on Finnish car markets and market changes. The major theoretical viewpoints are purchasing process, international purchasing and market analysis. The empirical part of the thesis concentrates on the major changes in Finnish car markets. The most important points are changes in car taxation and the big overall change in market situation.

Corporate Governance: Osakeyhtiön johdon velvollisuudet ja vastuu

Tutkimuksen tarkoituksena on selvittää, millainen Corporate Governance -järjestelmä ja sääntely-ympäristö Suomessa on voimassa. Tutkimuksessa tarkastellaan lisäksi osakeyhtiön johdon fidusiaarisia velvollisuuksia ja johdon velvollisuuksien tehosteena olevaa vastuujärjestelmää. Corporate Governance -järjestelmää analysoidaan perinteisestä oikeustieteellisestä näkökulmasta poiketen oikeustaloustieteen metodein. Tutkimuksen teoriapohja perustuu koti- ja ulkomaiseen oikeustaloustieteelliseen kirjallisuuteen, muutoin tutkimuksessa tukeudutaan suurimmilta osin kotimaiseen oikeuskirjallisuuteen ja virallislähteisiin. Suomalainen Corporate Governance -järjestelmä minimioi tehokkaasti transaktiokustannuksia ja tarjoaa osakkeenomistajille tehokkaan, informaation epäsymmetriaa rajoittavan valvontamekanismin. Jos johto toimii velvollisuuksiensa vastaisesti, osakkeenomistajat erottavat johdon, joka ei nauti sen luottamusta tai johto joutuu vastaamaan toimistaan vahingonkorvausvastuun tai rikosoikeudellisen vastuun kautta.

Inovação para a sustentabilidade

The transition to sustainable standards of production and consumption within a scenario of decreased availability of natural resources, growing population and climate change is essential to meet current challenges facing mankind. A strategy to meet these challenges should contain elements different from current approaches for industrial production. This work concentrates on the possibilities for the intensive use of sustainable biomass, abundant minerals and every type of residue, a task that can largely benefit from the application of nanotechnology and biotechnology platforms for material design and transformation. This strategy cannot be solely based on existing knowledge and requires new science, new knowledge including supposedly well-known themes, like the tribochemistry of electrostatic charging and friction. It is especially relevant within the Brazilian context, where many recent successful innovations are related to biomass production and transformation. Implementation of this strategy requires converging efforts by personnel from many different organizations and professions, while making sound risk assessment to produce significant innovation leading to sustainable development.