Pretreatment processes in gold recovery by thiosulphate leaching

This thesis describes several different pretreatment processes for gold concentrates and ores. The thesis is divided to theoretical part and experimental part. The theoretical part presents the operating principle of the main pretreatment methods and their suitability for thiosulphate leaching. In the theoretical part also the whole recovery process for gold from ore to elemental gold is presented. In the experimental part the study is focused on pretreatment of sulphidic refractory concentrates with mechanical activation and chemical oxidation under alkaline environment; and their effect on leachability in the thiosulphate leaching. In the experimental part a combined 2-step process, where chemical oxidation under ammoniacal environment is cascaded with thiosulphate leaching in the same conditions, is also tested. The main sulphuric mineral components in the studied refractory concentrate are pyrite (49.4 %) and arsenopyrite (27.7 %). The gold content in the concentrate is 11.3 ppm and silver content is 90 ppm. Without pretreatment the gold conversion in thiosulphate leaching was 30 %, which was analyzed at the time point of 9 hours. At that time the silver conversion was 17 %. By using mechanical activation the gold conversion reached was 59 % and silver conversion 26 %. With chemical oxidation under alkaline environment, where the used chemical was sodium hydroxide, the reached conversion of gold was 72 % and 31 % for silver. In the combined oxidation and leaching experiment the conversion of gold remained at 49 % and 18 % for silver.

Theorizing Formal and Informal Feedback Practices in Management Accounting Through Three Dimensions

The purpose of this doctoral thesis is to widen and develop our theoretical frameworks for discussion and analyses of feedback practices in management accounting, particularly shedding light on its formal and informal aspects. The concept of feedback in management accounting has conventionally been analyzed within cybernetic control theory, in which feedback flows as a diagnostic or comparative loop between measurable outputs and pre-set goals (see e.g. Flamholtz et al. 1985; Flamholtz 1996, 1983), i.e. as a formal feedback loop. However, the everyday feedback practices in organizations are combinations of formal and informal elements. In addition to technique-driven feedback approaches (like budgets, measurement, and reward systems) we could also categorize social feedback practices that managers see relevant and effective in the pursuit of organizational control. While cybernetics or control theories successfully capture rational and measured aspects of organizational performance and offer a broad organizational context for the analysis, many individual and informal aspects remain vague and isolated. In order to discuss and make sense of the heterogeneous field of interpretations of formal and informal feedback, both in theory and practice, dichotomous approaches seem to be insufficient. Therefore, I suggest an analytical framework of formal and informal feedback with three dimensions (3D’s): source, time, and rule. Based on an abductive analysis of the theoretical and empirical findings from an interpretive case study around a business unit called Division Steelco, the 3Dframework and formal and informal feedback practices are further elaborated vis-á-vis the four thematic layers in the organizational control model by Flamholtz et al. (1985; Flamholtz 1996, 1983): core control system, organizational structure, organizational culture, and external environment. Various personal and cultural meanings given to the formal and informal feedback practices (“feedback as something”) create multidimensional interpretative contexts. Multidimensional frameworks aim to capture and better understand both the variety of interpretations and their implications to the functionality of feedback practices, important in interpretive research.

Towards novel biogas upgrading processes

Biogas production has considerable development possibilities not only in Finland but all over the world since it is the easiest way of creating value out of various waste fractions and represents an alternative source of renewable energy. Development of efficient biogas upgrading technology has become an important issue since it improves the quality of biogas and for example facilitating its injection into the natural gas pipelines. Moreover, such upgrading contributes to resolving the issue of increasing CO2 emissions and addresses the increasing climate change concerns. Together with traditional CO2 capturing technologies a new class of recently emerged sorbents such as ionic liquids is claimed as promising media for gas separations. In this thesis, an extensive comparison of the performance of different solvents in terms of CO2 capture has been performed. The focus of the present study was on aqueous amine solutions and their mixtures, traditional ionic liquids, ‘switchable’ ionic liquids and poly(ionic liquid)s in order to reveal the best option for biogas upgrading. The CO2 capturing efficiency for the most promising solvents achieved values around 50 - 60 L CO2 / L absorbent. These values are superior to currently widely applied water wash biogas upgrading system. Regeneration of the solvent mixtures appeared to be challenging since the loss of initial efficiency upon CO2 release was in excess of 20 - 40 vol %, especially in the case of aqueous amine solutions. In contrast, some of the ionic liquids displayed reversible behavior. Thus, for selected “switchable” ionic and poly(ionic liquid)s the CO2 absorption/regeneration cycles were performed 3 - 4 times without any notable efficiency decrease. The viscosity issue, typical for ionic liquids upon CO2 saturation, was addressed and the information obtained was evaluated and related to the ionic interactions. The occurrence of volatile organic compounds (VOCs) before and after biogas upgrading was studied for biogas produced through anaerobic digestion of waste waters sludge. The ionic liquid [C4mim][OAc] demonstrated its feasibility as a promising scrubbing media and exhibited high efficiency in terms of the removal of VOCs. Upon application of this ionic liquid, the amount of identified VOCs was diminished by around 65 wt %, while the samples treated with the aqueous mixture of 15 wt % N-methyldiethanolamine with addition of 5 wt % piperazine resulted in 32 wt % reduction in the amounts of volatile organic compounds only.

Lean Accounting

Lean-filosofian keskeinen ajatus on tuottaa asiakkaalle enemmän arvoa vähentämällä turhuuksia tuotannosta. Keskeisessä roolissa lean-filosofiassa ovat arvo, arvovirta, flow, pull ja täydellisyys. Lean accounting on lean-tuotantofilosofiaa tukeva työkalu ja sen avulla voidaan kehittää sekä seurata lean-tuotantoa. Lean accountingissa tuotetaan selkeitä ja yksinkertaisia raportteja, joita koko organisaatio voi ymmärtää. Oleellista lean accountingissa on keskittyä yhden tuotteen kannattavuuden sijaan koko arvovirran kannattavuuteen. Tässä kandidaatintyössä käsitellään lean accountingia yleisesti. Työssä perehdytään perinteisen laskentatoimen ongelmiin lean-tuotannossa sekä esitellään sopivia työkaluja ja menetelmiä, jotka sopivat lean-yritykselle. Työssä on haasteltu Suomessa toimivia lean-yrityksiä heidän lean accounting ja lean-työkalujen tuntemuksesta. Työn tärkeyttä korostaa se, että lean accounting on huonosti tunnettu. Useat yritykset hyödyntävät lean-tuotantoa, mutta hyöty saattaa jäädä huomaamatta ilman lean accountingia. Lean accounting on havaittu hyväksi menetelmäksi ja siitä voi olla apua lean-yrityksille.

Knowledge, processes and relationships in organizational change: Understanding how to facilitate management of intellectual capital in diverse organization structures and cultures.

This study examined relationships of organizational dependencies, change management and developed intellectual knowledge resources, in different intellectual capital based development programs on ICT-sector. Study was carried out in a research context, where high degree of external organizational contingencies existed and lots of changes in several development programs had taken place in the last years. From a scientific perspective the main contribution was that evidence between relationships of organizational dependencies, change model portfolio and developed knowledge resources could be suggested. From managerial perspective the primary implication was that in situations where sustainable competitive advantage is pursued by means of increasing knowledge based productivity of labor, firms should seek to pursue organizational settings where external dependencies have minimal amount of effect.

Nordic banks’ entry into the Russian market: motives, processes and challenges

The importance of services in the global economy has grown steadily in the past decades and the growth of services sector’s direct investments has been increasing. Nowadays, all companies are influenced by the much changing global environment and the financial services companies are no exception. The internationalization of financial services companies is an expanding and accelerating phenomenon which has various motivations. The overall aim of this thesis is to shed light on the market entry processes of the Nordic financial services companies when they have entered the Russian market. In this study, the factors affecting Nordic banks’ market entry to Russia are presented in order to better understand what have been the main motives for market entry, what kind of processes the banks have used and what kind of challenges they have faced along the way. A case study approach was used in conducting the empirical research and it aims at investigating a specific case: Nordic banks’ entry into the Russian market. The empirical research was carried out by conducting qualitative interviews for employees involved in entry processes of the case banks. These interviews aimed at examining the Nordic banks’ motives for entering the Russian financial market. This includes reflections on the reasons why the studied banks have decided to enter Russia and what have been the motives behind these decisions. Also, the market entry processes the banks have used when they have entered the Russian market were investigated. The findings allowed comparing the related theories and different market entry modes the case banks have used. Furthermore, the market-related challenges faced by the case banks were mapped and described. In addition, the main factors related to the entry processes of the studied banks were identified and key elements of successful market entry were mapped. The findings suggest that the main motivator for banks have been to follow their customers and hence, increase the revenues and add the value to the shareholders; consequently, being a win-win-win situation to all the related parties. It was also discovered that the banks market entry processes have had resemblances but the banks have taken different paths to get where they are nowadays. As the Russian market environment differs from the one in Nordic countries, also challenges were faced by the case banks. However, the internal challenges were considered more troublesome than the external ones. As the foreign market entry process is complex as well as time and resources consuming, it is vital to understand the specifics of the target market, organizational capabilities and individuals enabling a successful entry process.

Suppurative intracranial processes in 15 domestic ruminants

In addition to listeriosis which is relatively common in ruminants, there are three other uncommon suppurative intracranial processes (SIP) identifiable in adult ungulates as brain abscess, basilar empyema and suppurative meningitis. The present paper reports the epidemiological, clinical, laboratorial, pathological and microbiological findings of 15 domestic ruminants with SIP. A total of 15 animals were selected (eight sheep, four cattle and three goats); with the definitive diagnoses of basilar empyema (n=3), brain abscess (n=1), listeriosis (n=5) and suppurative meningitis (n=6). Hematology revealed leukocytosis with inversion of the lymphocyte/ neutrophil ratio in 4 cases. In the majority of animals, cerebrospinal fluid (CSF) presented light yellow coloration and cloudy aspect due to neutrophilic pleocytosis (15 - 997 leukocytes/µL). Microbiological culture of CSF or central nervous system (CNS) fragments resulted on isolation of Trueperella (Arcanobacterium) pyogenes,Listeria monocytogenes,Escherichia coli and Stenotrophomonas sp. In a goat with thalamic abscess, microbiological assay was not performed, but Gram positive bacilli type bacteria were observed in histology. The diagnosis of these outbreaks was based on the association of epidemiological, clinical, pathological and bacteriological findings; reiterating that the infectious component remains an important cause of CNS disease in domestic ruminants and also shows the need for dissemination of information about the most effective preventive measures for the ranchers.

A temperature predicting model for manufacturing processes requiring coiling

A model for predicting temperature evolution for automatic controling systems in manufacturing processes requiring the coiling of bars in the transfer table is presented. Although the method is of a general nature, the presentation in this work refers to the manufacturing of steel plates in hot rolling mills. The predicting strategy is based on a mathematical model of the evolution of temperature in a coiling and uncoiling bar and is presented in the form of a parabolic partial differential equation for a shape changing domain. The mathematical model is solved numerically by a space discretization via geometrically adaptive finite elements which accomodate the change in shape of the domain, using a computationally novel treatment of the resulting thermal contact problem due to coiling. Time is discretized according to a Crank-Nicolson scheme. Since the actual physical process takes less time than the time required by the process controlling computer to solve the full mathematical model, a special predictive device was developed, in the form of a set of least squares polynomials, based on the off-line numerical solution of the mathematical model.

On the numerical simulation of machining processes

Numerical simulation of machining processes can be traced back to the early seventies when finite element models for continuous chip formation were proposed. The advent of fast computers and development of new techniques to model large plastic deformations have favoured machining simulation. Relevant aspects of finite element simulation of machining processes are discussed in this paper, such as solution methods, material models, thermo-mechanical coupling, friction models, chip separation and breakage strategies and meshing/re-meshing strategies.

Application of the finite element method in cold forging processes

The demand for more efficient manufacturing processes has been increasing in the last few years. The cold forging process is presented as a possible solution, because it allows the production of parts with a good surface finish and with good mechanical properties. Nevertheless, the cold forming sequence design is very empirical and it is based on the designer experience. The computational modeling of each forming process stage by the finite element method can make the sequence design faster and more efficient, decreasing the use of conventional "trial and error" methods. In this study, the application of a commercial general finite element software - ANSYS - has been applied to model a forming operation. Models have been developed to simulate the ring compression test and to simulate a basic forming operation (upsetting) that is applied in most of the cold forging parts sequences. The simulated upsetting operation is one stage of the automotive starter parts manufacturing process. Experiments have been done to obtain the stress-strain material curve, the material flow during the simulated stage, and the required forming force. These experiments provided results used as numerical model input data and as validation of model results. The comparison between experiments and numerical results confirms the developed methodology potential on die filling prediction.

Application of cutting fluids in machining processes

In the last decade a lot has been discussed about the suitability of using cutting fluid in abundance to cool and lubricate machining processes. The use of cutting fluid generally causes economy of tools and it becomes easier to keep tight tolerances and to maintain workpiece surface properties without damages. In the other hand, it brings also some problems, like fluid residuals and human diseases. Because of them some alternatives has been sought to minimise or even avoid the use of cutting fluid in machining operations. Some of these alternatives are dry cutting and cutting with minimum quantity of fluid (MQF). The main goal of this work is to discuss these tendencies. Therefore, topics like kinds and methods of applications of modern cutting fluids and what are new in this area will unavoidably be considered. MQF and dry cutting techniques, their applications and where it is not possible to apply them will also be focused. To exemplify the topics, this work will describe some of the researches been developed in two important Brazilian Universities: State University of Campinas (UNICAMP) and Federal University of Uberlândia (UFU).

Experimental Analysis of Fracture Processes in Concrete

This paper draws on the basic problems related to the determination of parameters to characterize the structural behavior of concretes using Fracture Mechanics concepts. Experimental procedures and results are discussed.

Identification of research trends in the field of separation processes. Application of epidemiological model, citation analysis, text mining, and technical analysis of the financial markets

Choice of industrial development options and the relevant allocation of the research funds become more and more difficult because of the increasing R&D costs and pressure for shorter development period. Forecast of the research progress is based on the analysis of the publications activity in the field of interest as well as on the dynamics of its change. Moreover, allocation of funds is hindered by exponential growth in the number of publications and patents. Thematic clusters become more and more difficult to identify, and their evolution hard to follow. The existing approaches of research field structuring and identification of its development are very limited. They do not identify the thematic clusters with adequate precision while the identified trends are often ambiguous. Therefore, there is a clear need to develop methods and tools, which are able to identify developing fields of research. The main objective of this Thesis is to develop tools and methods helping in the identification of the promising research topics in the field of separation processes. Two structuring methods as well as three approaches for identification of the development trends have been proposed. The proposed methods have been applied to the analysis of the research on distillation and filtration. The results show that the developed methods are universal and could be used to study of the various fields of research. The identified thematic clusters and the forecasted trends of their development have been confirmed in almost all tested cases. It proves the universality of the proposed methods. The results allow for identification of the fast-growing scientific fields as well as the topics characterized by stagnant or diminishing research activity.