Society by Numbers : Studies on Model-Based Explanations in the Social Sciences

The aim of this dissertation is to provide conceptual tools for the social scientist for clarifying, evaluating and comparing explanations of social phenomena based on formal mathematical models. The focus is on relatively simple theoretical models and simulations, not statistical models. These studies apply a theory of explanation according to which explanation is about tracing objective relations of dependence, knowledge of which enables answers to contrastive why and how-questions. This theory is developed further by delineating criteria for evaluating competing explanations and by applying the theory to social scientific modelling practices and to the key concepts of equilibrium and mechanism. The dissertation is comprised of an introductory essay and six published original research articles. The main theses about model-based explanations in the social sciences argued for in the articles are the following. 1) The concept of explanatory power, often used to argue for the superiority of one explanation over another, compasses five dimensions which are partially independent and involve some systematic trade-offs. 2) All equilibrium explanations do not causally explain the obtaining of the end equilibrium state with the multiple possible initial states. Instead, they often constitutively explain the macro property of the system with the micro properties of the parts (together with their organization). 3) There is an important ambivalence in the concept mechanism used in many model-based explanations and this difference corresponds to a difference between two alternative research heuristics. 4) Whether unrealistic assumptions in a model (such as a rational choice model) are detrimental to an explanation provided by the model depends on whether the representation of the explanatory dependency in the model is itself dependent on the particular unrealistic assumptions. Thus evaluating whether a literally false assumption in a model is problematic requires specifying exactly what is supposed to be explained and by what. 5) The question of whether an explanatory relationship depends on particular false assumptions can be explored with the process of derivational robustness analysis and the importance of robustness analysis accounts for some of the puzzling features of the tradition of model-building in economics. 6) The fact that economists have been relatively reluctant to use true agent-based simulations to formulate explanations can partially be explained by the specific ideal of scientific understanding implicit in the practise of orthodox economics.

Kirjan tie lukijalle : Kirjakauppojen vakiintuminen Suomessa 1740 - 1860

Books Paths to Readers describes the history of the origins and consolidation of modern and open book stores in Finland 1740 1860. The thesis approaches the book trade as a part of a print culture. Instead of literary studies choice to concentrate on texts and writers, book history seeks to describe the print culture of a society and how the literary activities and societies interconnect. For book historians, printed works are creations of various individuals and groups: writers, printers, editors, book sellers, censors, critics and finally, readers. They all take part in the creation, delivery and interpretation of printed works. The study reveals the ways selling and distributing books have influenced the printed works and the literary and print culture. The research period 1740 1860 covers the so-called second revolution of the book, or the modernisation of the print culture. The thesis describes the history of 60 book stores and their 96 owners. The study concentrates on three themes: firstly, how the particular book trade network became a central institution for printed works distribution, secondly what were the relations between cosmopolitan European book markets and the national cultural sphere, and thirdly how book stores functioned as cultural institutions and business enterprises. Book stores that have a varied assortment and are targeted to all readers became the main institution for book trade in Finland during 1740 1860. It happened because of three features. First, the book binders monopoly on selling bound copies in Sweden was abolished in 1740s. As a consequence entrepreneurs could concentrate solely to trade activities and offer copies from various publishers at their stores. Secondly the common business model of bartering was replaced by selling copies for cash, first in the German book trade centre Leipzig in 1770s. The change intensified book markets activities and Finnish book stores foreign connections. Thirdly, after Finland was annexed to the Russian empire in 1809, the Grand duchy s administration steered foreign book trade to book stores (because of censorship demands). Up to 1830 s book stores were available only in Helsinki and Turku. During next ten years book stores opened in six regional centres. The early entrepreneurs ran usually vertical businesses consisting of printing, publishing and distribution activities. This strategy lowered costs, eased the delivery of printed works and helped to create elaborated centres for all book activities. These book stores main clientele consisted of the Swedish speaking gentry. During late 1840s various opinion leaders called for the development of a national Finnish print culture, and also book stores. As a result, during the five years before the beginning of the Crimean war (1853 1856) book stores were opened in almost all Finnish towns: at the beginning of the war 36 book stores operated in 21 towns. The later book sellers, mainly functioning in small towns among Finnish speaking people, settled usually strictly for selling activities. Book stores received most of their revenues from selling foreign titles. Swedish, German, French and Belgian (pirate editions of popular French novels) books were widely available for the multilingual gentry. Foreign titles and copies brought in most of the revenues. Censorship inspections or unfavourable custom fees would not limit the imports. Even if the local Finnish print production steadily rose, many copies, even titles, were never delivered via book stores. Only during the 1840 s and 1850 s the most advanced publishers would concentrate on creating publishing programmes and delivering their titles via book stores. Book sellers regulated commissions were small. They got even smaller because of large amounts of unsold copies, various and usual misunderstandings of consignments and accounts or plain accidents that destroyed shipments and warehouses. Also, the cultural aim of a creating large and assortments and the tendency of short selling periods demanded professional entrepreneurship, which many small town book sellers however lacked. In the midst of troublesome business efforts, co-operation and mutual concern of the book market s entrepreneurs were the key elements of the trade, although on local level book sellers would compete, sometimes even ferociously. The difficult circumstances (new censorship decree of 1850, Crimean war) and lack of entrepreneurship, experience and customers meant that half of the book stores opened in 1845 1860 was shut in less than five years. In 1858 the few leading publishers established The Finnish Book Publishers Association. Its first task was to create new business rules and manners for the book trade. The association s activities began to professionalise the whole network, but at the same time the earlier independence of regional publishing and selling enterprises diminished greatly. The consolidation of modern and open book store network in Finland is a history of a slow and complex development without clear signs of a beginning or an end. The ideal book store model was rarely accomplished in its all features. Nevertheless, book stores became the norm of the book trade. They managed to offer larger selections, reached larger clienteles and maintained constant activity better than any other book distribution model. In essential, the book stores methods have not changed up to present times.

Salaiset aseveljet : Suomen ja Saksan turvallisuuspoliisiyhteistyö 1933-1944

Salaiset aseveljet deals with the relations and co-operation between Finnish and German security police authorities, the Finnish valtiollinen poliisi and the German Reichssicherheitshauptamt (RSHA) and its predecessors. The timeframe for the research stretches from the Nazi seizure of power in 1933 to the end of German-Finnish co-belligerency in 1944. The Finnish Security Police was founded in 1919 to protect the young Finnish Republic from the Communists both in Finland and in Soviet Russia. Professional ties to German colleagues were maintained during the 1920 s, and quickly re-established after the Nazis rose to power in Germany. Typical forms of co-operation concentrated on the fight against both domestic and international Communism, a concern particularly acute in Finland because of her exposed position as a neighbour to the Soviet Union. The common enemy proved to be a powerful unifying concept. During the 1930 s the forms of co-operation developed from regular and routine exchanges of information into personal acquaintancies between the Finnish Security Police top personnel and the highest SS-leadership. The critical period of German-Finnish security police co-operation began in 1941, as Finland joined the German assault on the Soviet Union. Together with the Finnish Security Police, the RSHA set up a previously unknown special unit, the Einsatzkommando Finnland, entrusted with the destruction of the perceived ideological and racial enemies on the northernmost part of the German Eastern Front. Joint actions in northern Finland led also members of the Finnish Security Police to become participants in mass murders of Communists and Jews. Post-war criminal investigations into war crimes cases involving former security police personnel were invariably stymied because of the absence of usually both the suspects and the evidence. In my research I have sought to combine the evidence gathered through an exhaustive study of Finnish Security Police archival material with a wide selection of foreign sources. Important new evidence has been gathered from archives in Germany, Estonia, Latvia, Sweden and the United States. Piece by piece, it has become possible to draw a comprehensive picture of the ultimately fateful relationship of the Finnish Security Police to its mighty German colleague.

Tanska keisari Kaarle V:n valtakunnan intresseissä 1521-1524

The master's thesis concerns the decisions of the imperial policy-makers in their Danish foreign policy during the crisis that culminated in the dissolution of the Nordic union of Kalmar during the years 1521-24. The sources consist of printed sources that mainly are collections of letters and diplomas, and additionally, acquaintance has been made with studies treating the subject. The aim of the study was to clarify the objectives, means and execution of the imperial policy and what priorizations did they make between the different objectives. Also, the part played by Denmark in the imperial foreign policy in general was to be assessed. Particularly, the aim was to find out and state a hierarchy between the importance of the different objectives by analyzing the choices made. It was observed that the continuing of peaceful relations in the North was clearly preferred in the imperial policy, especially as their war against France drew out. A war was seen as deteriorating the freedom of action of the main ally, king Christian II, and an armed conflict was to be prevented. The conceived impossibilty to intervene with armed forces to Christian's favour forced the imperial side to postpone their objectives in the fields of dynastical and alliance policy. In comparison to these, less weight was given to maintaining the rights and position of the empire and the rights granted in its name. To the Habsburgs, maintaining the economical embargo of Sweden, run forcefully by Christian II, was the least preferred objective. In light of the results of the master's thesis, the conceived priorities of the Northern European policy adopted by the imperial side resembled their political priorities in general.

Remembering Jock Young: Some sociological and personal reflections

Jock Young intellectually, politically, and personally touched the lives of many people. Thus, it is not surprising that his departure from this world on November 16, 2013 generated much shock, disbelief, and sadness. This article offers some personal and sociological reflections on Jock’s many contributions to critical criminology.

Ranskan rooli ja asema läntisessä liittoutumassa neljännen ja viidennen tasavallan vaihtumakohdassa 1956-1958

The study discusses the position of France as the United States’ ally in NATO in 1956-1958. The concrete position of France and the role that it was envisioned to have are being treated from the point of view of three participants of the Cold War: France, the United States and the Soviet Union. How did these different parties perceive the question and did these views change when the French Fourth Republic turned into the Fifth in 1958? The study is based on published French and American documents of Foreign Affairs. Because of problems with accessibility to the Soviet archival sources, the study uses reports on France-NATO relations of Pravda newspaper, the official organ of the Communist Party of the USSR, to provide information about how the Soviet side saw the question. Due to the nature and use of source material, and the chronological structure of the work, the study belongs methodologically to the research field of History of International Relations. As distinct from political scientists’ field of research, more prone to theorize, the study is characteristically a historical research, a work based on qualitative method and original sources that aims at creating a coherent narrative of the views expressed during the period covered by the study. France’s road to a full membership of NATO is being treated on the basis of research literature, after which discussions about France’s position in the Western Alliance are being chronologically traced for the period of last years of the Fourth Republic and the immediate months of coming back to power of Charles de Gaulle. Right from the spring of 1956 there can be seen aspirations of France, on one hand, to maintain her freedom of action inside the Western Alliance and, on the other, to widen the dialogue between the allies. The decision on France’s own nuclear deterrent was made already during the Fourth Republic, when it was thought to become part of NATO’s common defence. This was to change with de Gaulle. The USA felt that France still fancied herself as a great power and that she could not participate in full in NATO’s common defence because of her colonies. The Soviet Union saw the concrete position of France in the Alliance as in complete dependence on the USA, but her desired role was expressed largely in “Gaullist” terms. The expressions used by the General and the Soviet propaganda were close to each other, but the Soviet Union could not support de Gaulle without endangering the position of the French Communist Party. Between the Fourth and Fifth Republics no great rupture in content took place concerning the views of France’s role and position in the Western Alliance. The questions posed by de Gaulle had been expressed during the whole period of Fourth Republic’s existence. Instead, along with the General the weight and rhetoric of these questions saw a great change. Already in the early phase the Americans saw it possible that with de Gaulle, France would try to change her role. The rupture took place in the form of expression, rather than in its content.

Drag på parnassen. Två sextiotalsstudier. : Del I: Medelklass med mänskligt ansikte. Medelklassradikalism i fyra romaner av Christer Kihlman, Jarl Sjöblom, Marianne Alopaeus och Ulla-Lena Lundberg. Del II: Modernistdebatten. Sak, person och fält i en finlandssvensk litteraturdebatt år 1965.

The objective of my dissertation Pull (or Draught, or Moves) at the Parnassus , is to provide a deeper understanding of Nordic Middle Class radicalism of the 1960 s as featured in Finland-Swedish literature. My approach is cultural materialist in a broad sense; social class is regarded a crucial aspect of the contents and contexts of the novels and literary discussions explored. In the first volume, Middle Class With A Human Face , novels by Christer Kihlman, Jarl Sjöblom, Marianne Alopaeus, and Ulla-Lena Lundberg, respectively, are read from the points of view of place, emotion, and power. The term "cryptotope" is used to designate the hidden places found to play an important role in all of these four narratives. Also, the "chronotope of the provincial small town", described by Mikhail Bakhtin in 1938, is exemplified in Kihlman s satirical novel, as is the chronotope of of war (Algeria, Vietnam) in those of Alopaeus and Lundberg s. All the four novels signal changes in the way general "scripts of emotions", e.g. jealousy, are handled and described. The power relations in the novels are also read, with reference to Michel Foucault. As the protagonists in two of them work as journalists, a critical discussion about media and Bourgeois hegemony is found; the term "repressive legitimation" is created to grasp these patterns of manipulation. The Modernist Debate , part II of the study, concerns a literary discussion between mainly Finland-Swedish authors and critics. Essayist Johannes Salminen (40) provided much of the fuel for the debate in 1963, questioning the relevance to contemporary life of the Finland-Swedish modernist tradition of the 1910 s and 1920 s. In 1965, a group of younger authors and critics, including poet Claes Andersson (28), followed up this critique in a debate taking place mainly in the newspaper Vasabladet. Poets Rabbe Enckell (62), Bo Carpelan (39) and others defended a timeless poetry. This debate is contextualized and the changing literary field is analyzed using concepts provided by sociologist Pierre Bourdieu. In the thesis, the historical moment of Middle Class radicalism with a human face is regarded a temporary luxury that new social groups could afford themselves, as long as they were knocking over the statues and symbols of the Old Bourgeoisie. This is not to say that all components of the Sixties strategy have lost their power. Some of them have survived and even grown, others remain latent in the gene bank of utopias, waiting for new moments of change.

Phosphorus nutrition and tolerance of cotton to water stress: II. Water relations, free and bound water and leaf expansion rate

In previous experiments, increased leaf-Phosphorus (P) content with increasing P supply enhanced the individual leaf expansion and water content of fresh cotton leaves in a severely drying soil. In this paper, we report on the bulk water content of leaves and its components, free and bound water, along with other measures of plant water status, in expanding cotton leaves of various ages in a drying soil with different P concentrations. The bound water in living tissue is more likely to play a major role in tolerance to abiotic stresses by maintaining the structural integrity and/or cell wall extensibility of the leaves, whilst an increased amount of free water might be able to enhance solute accumulation, leading to better osmotic adjustment and tolerance to water stress, and maintenance of the volumes of sub-cellular compartments for expansive leaf growth. There were strong correlations between leaf-P%, leaf water (total, free and bound water) and leaf expansion rate (LER) under water stress conditions in a severely drying soil. Increased soil-P enhanced the uptake of P from a drying soil, leading to increased supply of osmotically active inorganic solutes to the cells in growing leaves. This appears to have led to the accumulation of free water and more bound water, ultimately leading to increased leaf expansion rates as compared to plants in low P soil under similar water stress conditions. The greater amount of bound and free water in the high-P plants was not necessarily associated with changes in cell turgor, and appears to have maintained the cell-wall properties and extensibility under water stressed conditions in soils that are nutritionally P-deficient.

Heräämisten poetiikkaa : Lajeja ja intertekstejä Arvid Järnefeltin romaaneissa Isänmaa, Maaemon lapsia ja Veneh'ojalaiset

Poetics of Awakenings. Genres and Intertexts in Arvid Järnefelt s Novels Isänmaa, Maaemon lapsia and Veneh ojalaiset This doctoral dissertation focuses on Arvid Järnefelt s (1961 1932) novels Isänmaa (1893), Maaemon lapsia (1905) and Veneh ojalaiset (1909). The study applies the genre theory and concepts Alastair Fowler has introduced in his Kinds of Literature (1982). Fowler s theory of the novel is developed further and applied to Finnish realist novels. The generic analysis is supplemented by intertextual analysis, which is mainly based on the idea of specific intertextual relations as presented by Kiril Taranovsky. Generic and intertextual analyses form the basis for hermeneutic interpretation, in which attention is paid to the fact that the novels are written by the designated writer in specific historical and cultural circumstances. Instead of the author s intention , the study focuses on the realised intention , in other words the novels as they are published. Järnefelt s first novel Isänmaa is understood to be a classical Bidungsroman that depicts the socialisation of a young male protagonist. From an intertextual point of view, the novel appears to be a novel of conversion, too, due to the biblical allusions concealed in the depiction of the events. Furthermore, Isänmaa is seen to stand in an intertextual relation to Hegel s, Snellman s and Topelius s writings. Maaemon lapsia is argued to be a thesis novel, which persuades the reader to adopt a certain ideological and political stance, namely Henry George s view on the private ownership of land. The novel is modulated by the generic repertoires of fairy tale and tragedy. The mythical frame of the novel supports the thesis novel, as it gives universal validity to the particular events depicted in the novel. Maaemon lapsia also comments on the contemporary political debate on the relations between Finland and Russia by presenting the relationship as analogous to the relationship between tenant farmer and landowner. Veneh ojalaiset exhibits a wide range of genres. Comic, tragic and mythical mode is combined with, for example, family novel, romance, conversion novel and revolutionary novel. From a rhetorical viewpoint, the novel is an apology, which accuses society of generating criminality by means of unjust laws and procedures. The novel discusses the question of resistance to evil by using the themes of Faust and Job, as well as by confronting the philosophies of Epictetus and Nietzsche. The novel is a thesis novel, which disputes the possibility of violent revolution as a way to a better society and recommends passive resistance for an individual living in an unjust society. The poetics of Järnefelt s novels is regarded as the poetics of conversion, as all the novels in focus depict the protagonist s awakening to see the society in a new light, be it a patriotic vision of the reality or a conception of the unfairness of society.

Kuvan ja tekstin välissä : Kuvateksti uutiskuvan ja lehtijutun elementtinä

The study focuses on picture captions: their grammar and interplay with photographs and their position as semi-independent elements of the news stories. The research was conducted in the framework of critical discourse analysis, social semiotic visual theory and fennistic syntactical research. The data consist of 441 press photographs, 1,815 captions and a number of news items from Finnish dailies. The generic structure potential of the caption includes the caption headline, the caption proper, i.e. the verbalization of the picture content, and the frame. In the data, 41 per cent of the captions have a headline, and 44 per cent contain a caption proper. Characteristic of the caption proper is omission of the finite verb and the use of the present tense, both of which have decreased in Finnish papers during the 20th century. The caption proper is typically a main clause, and both subordinate clauses and participal phrases occur mostly in the frame. While comparing caption variants attached to the same pictures, the processes and their participants proved to be identified considerably identically, following the news agency captions. Instead, the reader?s interpretations of a picture could be directed by framing it in different ways. For example, the caption may focus on the only person depicted, deal with a whole group, or give an abstract account of the situation. The caption is a paratext, a typographically marked, semi-independent element of a news story. Between the headline and the caption, four semantic relations have been identified. The caption may be a paraphrase of the headline, or a close-up illustrating an abstract headline with a concrete example. If the name of the person depicted is their only common factor, the relation between the caption and the headline is additive. A specifying caption will give more details than the headline. The caption may complete, repeat, or summarize the body copy. Naturally, most captions completing the story verbalize the content of the picture. As the caption is often based on the story, it may even repeat the body copy verbatim. The summarizing function is probably becoming increasingly important, as most Finnish newspapers have abandoned the use of a separate standfirst.

J. L. Runebergs samlade skrifter i textkritisk belysning

The Collected Works of J. L. Runeberg from the Viewpoint of Textual Scholarship The theoretical framework of this dissertation builds on textual scholarship. The dissertation explores the history of Runeberg’s publications and his relations with his publishers, from his debut and the first editions, through the editions of collected works published during the course of his life, to the later commercial editions, including the critical edition, published in 1933–2005 by the Svenska Vitterhetssamfundet (The Swedish Society for Belles Lettres) and The Svenska litteratursällskapet i Finland (The Society of Swedish Literature in Finland). The various editions of Runeberg’s collected works are situated in their respective critical traditions, from the 19th century German Ausgabe letzter Hand, to the influence of Anglo-American bibliography on Swedish textual criticism in the late 20th century. By making use of primary material previously not used for research purposes, the author is able to present a new view on Runebergian publishing history, including Runeberg’s fees and his relations with the censor authorities. There are indications that his Finnish publishers could not bear the cost of his sizable fees, that were in proportion neither with the book market in Finland nor with the numbers of copies sold. Apart from a certain body of editions the primary material is comprised of correspondences, publishing contracts, printing house invoices, as well as censor authority records. One of the conclusions drawn is that the early and detailed biography, Biografiska anteckningar om Johan Ludvig Runeberg (Biographical Notes on …) by J. E. Strömborg is not reliable in matters concerning publishing history, and that this work has been used far too uncritically. The history of the critical edition gets a chapter of its own, based on primary material in Swedish and Finnish archives. Finally, the author analyses the critical choices, made primarily in the critical edition, and uses examples from the commercial editions to study the editors’ interventions over time, from the 1850s to the 1920s. The changes to the text are usually small and subtle, but cumulative – and in some cases, crucial for the interpretation of the work. One objective of textual scholarship should be to examine the publishing history of a single work or of an author’s œuvre, and another to pay attention both to changes in a work as such and to the shifts of meaning they might entail.

Le naturalisme finlandais : Une conception entropique du quotidien

Le naturalisme finlandais. Une conception entropique du quotidien. Finnish Naturalism. An Entropic Conception of Everyday Life. Nineteenth century naturalism was a strikingly international literary movement. After emerging in France in the 1870s, it spread all over Europe including young, small nations with a relatively recent literary tradition, such as Finland. This thesis surveys the role and influence of French naturalism on the Finnish literature of the 1880s and 1890s. On the basis of a selection of works of six Finnish authors (Juhani Aho, Minna Canth, Kauppis-Heikki, Teuvo Pakkala, Ina Lange and Karl August Tavaststjerna), the study establishes a view of the main features of Finnish naturalism in comparison with that of French authors, such as Zola, Maupassant and Flaubert. The study s methodological framework is genre theory: even though naturalist writers insisted on a transparent description of reality, naturalist texts are firmly rooted in general generic categories with definable relations and constants on which European novels impose variations. By means of two key concepts, entropy and everyday life , this thesis establishes the parameters of the naturalist genre. At the heart of the naturalist novel is a movement in the direction of disintegration and confusion, from order to disorder, from illusion to disillusion. This entropic vision is merged into the representation of everyday life, focusing on socially mediocre characters and discovering their miseries in all their banality and daily grayness. By using Mikhail Bakhtin s idea of literary genres as a means of understanding experience, this thesis suggests that everyday life is an ideological core of naturalist literature that determines not only its thematic but also generic distinctions: with relation to other genres, such as to Balzac s realism, naturalism appears primarily to be a banalization of everyday life. In idyllic genres, everyday life can be represented by means of sublimation, but a naturalist novel establishes a distressing, negative everyday life and thus strives to take a critical view of the modern society. Beside the central themes, the study surveys the generic blends in naturalism. The thesis analyzes how the coalition of naturalism and the melodramatic mode in the work of Minna Canth serves naturalisms ambition to discover the unconscious instincts underlying daily realities, and how the symbolic mode in the work of Juhani Aho duplicates the semantic level of the apparently insignificant, everyday naturalist details. The study compares the naturalist novel to the ideological novel (roman à these) and surveys the central dilemma of naturalism, the confrontation between the optimistic belief in social reform and the pessimistic theory of determinism. The thesis proposes that the naturalist novel s contribution to social reform lies in its shock effect. By means of representing the unpleasant truth the entropy of everyday life it aims to scandalize the reader and make him aware of the harsh realities that might apply also to him.

Fostering interpersonal trust on social media: Physicians' perspectives and experiences

Background The problem of developing and sustaining mutual trust is one of the main barriers to knowledge sharing on social media platforms such as blogs, wikis, micro-blogs and social networking websites. While many studies argue that mutual trust is necessary for online communication and knowledge sharing, few have actually explored and demonstrated how physicians can establish and sustain trusted relationships on social media. Objectives To identify approaches through which physicians establish interpersonal trust on social media. Methods Twenty-four physicians, who were active users of social media, were interviewed using a semi-structured approach between 2013 and 2014. Snowball sampling was employed for participant recruitment. The data were analysed using a thematic analysis approach. Results Physicians trust their peers on social media in a slightly different way than in face-to-face communication. The study found that the majority of participants established trust on social media mainly through previous personal interaction, authenticity and relevancy of voice, professional standing, consistency of communication, peer recommendation, and non-anonymous and moderated sites. Conclusions Healthcare professionals need to approach social media carefully when using it for knowledge sharing, networking and developing trusted relations with like-minded peers.

Phase relations in the system Ta-Rh-O and thermodynamic properties of TaRhO4

Phase relations in the system Ta-Rh-O were determined by analysis of quenched samples corresponding to thirteen compositions inside the ternary triangle after equilibration at 1273 K. All the Ta-Rh alloys were found to be in equilibrium with Ta2O5. Only one ternary oxide TaRhO4 was detected. Based on phase relations in the ternary system, a solid-state electrochemical cell, incorporating calcia-stabilized zirconia as the electrolyte, was designed to measure the standard Gibbs energy of formation (Delta G degrees, J mol(-1)) of TaRhO4 in the temperature range from 900 to 1300 K. For the reaction, 1/2 beta-Ta2O5 + 1/2 Rh2O3(ortho) -> TaRhO4 Delta G degrees = -42993 + 5.676T (+/- 85) The calculated decomposition temperatures of TaRhO4 are 1644 +/- 5K in pure O-2 and 1543 +/- 5K in air at a total pressure p(o) = 0.1 MPa. Thermodynamic properties of TaRhO4 at 298.15K have been evaluated from the results. The limited experimental thermodynamic data for Rh-rich alloys available in the literature are in fair accord with Miedema's model. The Gibbs energies of formation of the different phases in the binary system Ta-Rh were estimated based on these inputs, consistent with the binary phase diagram. Based on the thermodynamic information on the stability of various phases, an oxygen potential diagram for the system Ta-Rh-O at 1273K was constructed. Also presented are temperature-composition diagrams for the ternary system at constant oxygen partial pressures (po(2)/p(o) = 0.212 and 10(-6)) calculated form the basic data.

Phase relations between Al2O3---Cr2O3 and FeAl2O4---FeCr2O4 solid solutions at 1823 K

Tie-lines between the corundum and spinel solid solutions have been determined experimentally at 1823 K. Next, activities of FeCr2O4 and FeAl2O4 in the spinel solid solution were determined by combining the tie-line data with literature values for the activities of Cr2O3 and Al2O3 in the corundum phase. Activities and the Gibbs energy of mixing for the spinel solid solution were also obtained from a model based on cation distribution between nonequivalent crystallographic sites in the oxide lattice. The difference between the Gibbs energy of mixing obtained experimentally and from the model has been attributed to a strain enthalpy term which is relatively unchanged in magnitude from the reported at 1373 K. The integral enthalpy of mixing obtained from experimental data at 1373 and 1823 K using the second law is compared with the model result.