Thermochemical and kinetic studies on the effects of cobalt salicylate on the oxidative degradation of polystyrene

The effect of cobalt salicylate on the oxidative degradation and ignition of polystyrene has been studied. It was found that cobalt salicylate sensitizes both the degradation and ignition of polystyrene by facilitating electron-transfer processes in the propagation step. From thermochemical and kinetic studies it was found that the cobalt ion, owing to its ability to exist in variable valence states, promotes electron transfer in the propagation step of polymer degradation, increasing the rate of propagation and consequently the overall rate. Using solid-phase thermal ignition theory, an attempt has been made to explain the sensitization of ignition by the cobalt ion.

Dielectric Relaxation in SrLiB9O15 Glasses

Transparent SrLiB9O15 (SLBO) glasses were fabricated via the conventional melt-quenching technique. X-ray powder diffraction and differential thermal analysis carried out on the as-quenched samples confirmed their amorphous and glassy nature, respectively. The dielectric constants in the 100 Hz to 10 MHz frequency range for SLBO glasses were measured as a function of temperature (300–1023 K). The dielectric relaxation characteristics were rationalized using the electric modulus formalism. The electrode polarization effect was subtracted from the low-frequency dielectric constant to have an insight into the intrinsic dielectric behavior of SLBO glasses. The imaginary part of electric modulus spectra was modeled using an approximate solution of Kohlrausch–Williams–Watts relation. The dielectric constant for the as-quenched glass increased with increasing temperature and exhibited anomalies in the vicinity of the glass transition and crystallization temperatures.

Thermoanalysis of ammonium perchlorate and sodium nitrate mixture

A binary mixture of ammonium perchlorate-sodium nitrate in molar proportion undergoes partial fusion at 223°C and the transformation of the mixture to sodium perchlorate-ammonium nitrate occurs in the broad endothermic region. The mixture was heated and quenched at various temperatures in a differential thermal analysis assembly. Thermogravimetric analysis, X-ray diffraction, and infrared spectroscopic techniques were used to determine the composition of the quenched sample in order to explain the overall thermal phenomenon. Visual observations of the morphological changes that occur during the course of heating were made using a hot-stage microscope, 30–350°C.

Effect of Pressure on Polymer Ignition

Auto-ignition temperature of polystyrene, poly(vinyl chloride) and carboxy terminated polybutadiene has been measured at various oxygen pressures (1-28 atm) in a high pressure differential thermal analysis assembly at a heating rate of 10°C/min. The exothermic peak appears between 250-350°C in polystyrene and poly(vinyl chloride) and between 150-200°C for carboxy terminated polybutadiene. Ignition appears to be controlled by in situ forma tion and degradation of polymeric peroxides. Inverse dependence of ignition temperature on oxygen pressure is explained by the rate equation which con siders that ignition of a particular sample, of a fixed geometry, occurs when gasification rate reaches a unique critical value.

Käsityksistä ajatuksen poluille : Ammattikorkeakoulun tutkimus- ja kehitystoiminnan kehittäminen

This study deals with the formation of the idea of research and development (r&d) activity at one particular university of applied sciences in Finland. In this study I proceed from examining the conceptions of management regarding r&d-activities to exploring the development of the complex concept that guides these r&d-activities. The aim of this study is, first, to describe conceptions of r&d-activities, and then, second, to describe the formation of a new concept for r&d-activities in one field of study at the university of applied sciences. I used phenomenographic analysis to elucidate the conceptions and collected the data in interviews of personnel (22) who belong to the management of the university of applied sciences. The data for analysing the obstacles faced and the ways of overcoming them during the formation process of the new concept consist of the video-recorded material from ten change laboratory sessions held for the specific field of study at the university of applied sciences. In researching the formation of the concept of the activity, such research and analysis methods are used in which the concept is understood as a material construction, and with the help of which one can work out the formation of the concept during the development process. When the systematic development of the r&d-work was underway, the management of the university of applied sciences held differing views regarding the content, target, factors and organisation of the r&d-activities, as well as regarding the position of dissertations as a part of r&d-activity. Obstacles for developing rd concerned the unclear object and outcomes of the new activity, not having the tools (such as adequate know-how) for the new activity and not having found the necessary solutions for the distribution of work. In addition the rules that quide the activities of the university of applied sciences did not support working according to the new way. To improve r&d-activity, the school’s management defined three development strategies to encourage adequate rd-activity to support working life, regional development and learning. The strategies were based on the expansion of existing methods, such as service activities, dissertation work and the research activities of the teachers. Of the three possible routes, the concept of dissertation in this study was expanded to integrate the services of organisation development and the occupational growth of the students. A group of teachers in the field of social and health studies participated in the development work. The change laboratory method was used as a tool for this work. Analysis of the cognitive trails indicated that, in addition to the cycle of expansive learning activities, microcycles with different purposes can exist. According to Cussins (1992), something already in existence in each microcycle is destabilised, and something else is stabilised to replace it. In this study three microcycles were identified, during which the teachers first destabilised the existing concepts of dissertation work that guided their thinking, and then began to use new concepts to structure their thinking. Secondly, they undermined the existing concepts with material structure that defined their practical work, and developed new practical models to replace them. Thirdly, the problems accumulating in researching and testing the new activities caused the developers to destabilise the r&d-strategies of the university of applied sciences and to define a new conceptual model for r&d-work in the field. During this third cycle, the teachers developed a research arena model, which was a significant expansive innovation. In the cognitive trails developing the new concept for the r&d-activity, the teachers indeed faced the obstacles the management had described as their conceptions. These obstacles manifested themselves as contradictions. During the development process, the nature of the obstacles (i.e. contradictions) changed as the development proceeded. Solving the first and second degree contradictions highlighted the third and fourth degree contradictions. To overcome the obstacles, the teachers had to to articulate the value and motive of the development work throughout the development process. Developing the new concept for r&d-activity required many reconfigurations of practical solutions to overcome the obstacles. Developing the new concept for r&d-activity, both at the level of representations and of new practices, requires universities of applied sciences to adopt new methods in which the actors are partake in construction of new concepts of activity through adequate discussion, analysis and debate. R&d -activity can progress, if instead of implementing partial solutions, the totality of the activities (i.e. the group of partial solutions acting together) will be constructed. The development of the activity system requires many simultaneous changes as well as wide-ranging know-how and discussion related to these changes. What is perhaps most important, however, is that the group of developers mature into a determined collective actor which can engage in many agentive actions. The development of the agency is fundamental to progress.

Laatutyöhön sitoutumisen edellytykset ammattikorkeakoulussa

The goal of this research was to establish the necessary conditions under which individuals are prepared to commit themselves to quality assurance work in the organisation of a Polytechnic. The conditions were studied using four main concepts: awareness of quality, commitment to the organisation, leadership and work welfare. First, individuals were asked to describe these four concepts. Then, relationships between the concepts were analysed in order to establish the conditions for the commitment of an individual towards quality assurance work (QA). The study group comprised the entire personnel of Helsinki Polytechnic, of which 341 (44.5%) individuals participated. Mixed methods were used as the methodological base. A questionnaire and interviews were used as the research methods. The data from the interviews were used for the validation of the results, as well as for completing the analysis. The results of these interviews and analyses were integrated using the concurrent nested design method. In addition, the questionnaire was used to separately analyse the impressions and meanings of the awareness of quality and leadership, because, according to the pre-understanding, impressions of phenomena expressed in terms of reality have an influence on the commitment to QA. In addition to statistical figures, principal component analysis was used as a description method. For comparisons between groups, one way variance analysis and effect size analysis were used. For explaining the analysis methods, forward regression analysis and structural modelling were applied. As a result of the research it was found that 51% of the conditions necessary for a commitment to QA were explained by an individual’s experience/belief that QA was a method of development, that QA was possible to participate in and that the meaning of quality included both product and process qualities. If analysed separately, other main concepts (commitment to the organisation, leadership and work welfare) played only a small part in explaining an individual’s commitment. In the context of this research, a structural path model of the main concepts was built. In the model, the concepts were interconnected by paths created as a result of a literature search covering the main concepts, as well as a result of an analysis of the empirical material of this thesis work. The path model explained 46% of the necessary conditions under which individuals are prepared to commit themselves to QA. The most important path for achieving a commitment stemmed from product and system quality emanating from the new goals of the Polytechnic, moved through the individual’s experience that QA is a method of the total development of quality and ended in a commitment to QA. The second most important path stemmed from the individual’s experience of belonging to a supportive work community, moved through the supportive value of the job and through affective commitment to the organisation and ended in a commitment to QA. The third path stemmed from an individual’s experiences in participating in QA, moved through collective system quality and through these to the supportive value of the job to affective commitment to the organisation and ended in a commitment to QA. The final path in the path model stemmed from leadership by empowerment, moved through collective system quality, the supportive value of the job and an affective commitment to the organisation, and again, ended in a commitment to QA. As a result of the research, it was found that the individual’s functional department was an important factor in explaining the differences between groups. Therefore, it was found that understanding the processing of part cultures in the organisation is important when developing QA. Likewise, learning-teaching paradigms proved to be a differentiating factor. Individuals thinking according to the humanistic-constructivistic paradigm showed more commitment to QA than technological-rational thinkers. Also, it was proved that the QA training program did not increase commitment, as the path model demonstrated that those who participated in training showed 34% commitment, whereas those who did not showed 55% commitment. As a summary of the results it can be said that the necessary conditions under which individuals are prepared to commit themselves to QA cannot be treated in a reductionistic way. Instead, the conditions must be treated as one totality, with all the main concepts interacting simultaneously. Also, the theoretical framework of quality must include its dynamic aspect, which means the development of the work of the individual and learning through auditing. In addition, this dynamism includes the reflection of the paradigm of the functions of the individual as well as that of all parts of the organisation. It is important to understand and manage the various ways of thinking and the cultural differences produced by the fragmentation of the organisation. Finally, it seems possible that the path model can be generalised for use in any organisation development project where the personnel should be committed.

Studies on vacuum pyrolysis of ammonium perchlorate and ammonium perchlorate/polystyrene propellant in the presence of transition metal oxides

Vacuum pyrolysis of ammonium perchlorate (AP) and ammonium perchlorate/polystyrene (PS) propellant has been studied by differential thermal analysis (DTA) in order to observe the effect of transition metal oxides on sublimation. Sublimation and decomposition being competitive processes, their proportions depend on the pressure of the pyrolysis chamber. The enthalpies for complete decomposition and complete sublimation are available from the literature and by using these data together with DTA area measurements, the extents of sublimation and decomposition have been calculated for AP and the propellant system. The effect of the metal ions on the extent and rate of sublimation depends on their nature. For AP the extent of sublimation increases with a decrease in particle size. For the propellants the powder sublimes more readily than the bulk material, but in the presence of metal ions the bulk material sublimes more readily than the powder. To substantiate this finding, the effect of MnO2 on AP sublimation as a function of particle size was examined, and it was observed that the extent of sublimation decreases as the particle size decreases.

The role of transition metal oxides in the decomposition and explosion of arylammonium perchlorates

The influence of MnO2, CuO, and NiO on the thermal decomposition and explosivity of arylammonium perchlorates has been studied by differential thermal analysis (DTA) and explosive sensitivity measurements. The metal oxides considerably sensitize both decomposition and explosion and the sensitizing effect is in the order NiO < CuO < MnO2. The accelerated decomposition or explosion seems to occur via the formation of an intermediate, metal perchlorate arylamine complex. The experimental evidence for the mechanism put forward has been included.

Synthesis, characterization and photocatalytic activity of MxCe1-xVO4 (M = Li, Ca and Fe)

Non-stoichiometric substituted cerium vanadates, MxCe1-xVO4 (M = Li, Ca and Fe), were synthesized by solid-state reactions. The crystal structure was analyzed by powder X-ray diffraction and it exhibits a tetragonal zircon Structure, crystallizing in the space group I4(1)/amd with a = 7.3733(4) and c = 6.4909(4) angstrom and Z = 4. Particle sizes were in the range of 600-800 nm, as observed by scanning electron microscopy. The thermal analysis of the compounds showed phase stability up to 1100 degrees C. The UV diffuse reflectance spectra indicated that the compounds have band gaps in the range of 2.6-2.9 eV. The photocatalytic activity of these Compounds was investigated for the first time for the degradation of different dyes, and organics, the oxidation of cyclohexane and the hydroxylation of benzene. The degradation of dyes was modeled using the Langmuir-Hinshelwood kinetics, while the oxidation of cyclohexane and hydroxylation of benzene were modeled using a free radical mechanism and a series reaction mechanism, respectively.

Synthesis and Characterisation of Metal Hydrazine Nitrate, Azide and Perchlorate Complexes

Metal hydrazine nitrate complexes of the type M(N2H4)Nn (NO3)2 where M = Mg, n = 2; M = Mn, Fe, Co, Ni, Zn and Cd and n = 3; metal dihydrazine azide complexes of the type M(N2H4)2 (N3)2 where M = Mg, Co, Ni and Zn; and Mg(N2H4)2 (C1O4)2 have been prepared by dissolving the respective metal powders in the solution of corresponding ammonium salts (NO3, N3 and C1O4) in hydrazine hydrate. These hydrazine complexes were also prepared by the conventional method involving the addition of alcoholic hydrazine hydrate to the aqueous solution of metal salts. The hydrazine complexes have been characterised by chemical analysis, infrared spectra and differential thermal analysis (DTA). Impact sensitivities of hydrazine complexes were determined by the drop weight method. The reactivity of these hydrazine complexes does not change with the method of preparation.

Self-Concept and School Achievement of Pupils with Cleft Lip, Cleft Palate or Both : A longitudinal study

The goal of this research was to survey the self-concept and school achievement of pupils with cleft lip, cleft palate or both from juvenile age to adolescence. Longitudinal researches of self-concept and school achievement among pupils with cleft lip, cleft palate or both are uncommon. This research was the first longitudinal research ever conducted in Finland among this population. This research can be considered to be a special educational study because of the target group involved. Self-concept consists of the person s entire personality. Personality is biological and deterministic. Self-concept includes concepts, attitudes and feelings that the person has about him or her qualities, abilities and relations to the environment. The individual associates experiences to this personality with earlier observations through the social interaction. The individual will have the consciousness of the person s existence and action. The target group in this study consisted of Finnish children with clefts, who were comprised of four different age groups. The questionnaire was sent to all subjects (N1 = 419) both times. A total of 74 % of children returned the questionnaire in 1988 (N2=305). 48 % of children returned the questionnaire in 1993 (N3=203). 42% of children returned the questionnaire both times (N4=175) . These 175 children formed the research subjects. The survey was conducted in 1988, and again in 1993. In 1988, the pupils surveyed were 9 to 12 years of age, while in 1993 they were between 14 and 17 years old. The data was collected through the use of a questionnaire, which consisted of common questions and a personality inventory test that was developed for Finnish students by professor Maija-Liisa Rauste-von Wright. Quantitative analysis methods were used to examine the structure of self-concept and school achievement. Structures found in this research were observed in relation to disorder, gender and maturation. According to these results, structures of self-concepts and school achievement are in fact stable. Basic self-concept elements are seen to be formed at an early age. The developmental aspects of self-concept following puberty are observed as the stability of self-concept and as the forming of a general self. The level of school achievement is stable, but the structure of school achievement changes. From these results, it is possible to state that the gender of the child has a statistical significance regarding self-concept and school achievement. However, the experienced disorder does not have statistical significance as regards to self-concept and school achievement. Results of self-concept support the research of self-concept conducted earlier in Finland.

"Mut ei tää oo hei midsommarista!" - ruotsin kielen viestinnällinen suullinen harjoittelu yhteistoiminnallisten skeema- ja elaborointitehtävien avulla

Communicative oral practice in Swedish through collaborative schema-based and elaboration tasks The general aim of this study was to learn how to better understand foreign language communicative oral practice and to develop it as part of communicative language teaching. The language-specific aim was to study how Swedish was being practised communicatively and orally in a classroom context as part of the didactic teaching-studying-learning process, and how the students' communicative oral practice in Swedish was carried out through collaborative schema-based and elaboration tasks. The scientific problem of this study focused on the essence of foreign language communicative oral proficiency. The research questions were concerned with 1) the students' involvement in carrying out the given oral tasks; 2) the features of communication and interaction strategies; 3) thematic vocabulary, and 4) the students' experiences and conceptions of the communicative oral tasks used. The study consisted of two groups of students from a Helsinki-area school (a group of upper secondary school students, Swedish Level A, Courses 2 and 3, n=9; and a group of basic education students, Swedish Level B, Course 2, n=13). The study was carried out as a pedagogically oriented case study which included certain features of ethnographic research and where the students' teacher acted as a researcher of her own work. The communicative oral practice contained five different tasks. The research data were gathered through systematic observation, audio recordings and by a questionnaire. The data were analysed through ethnographic content analysis methods. The main research finding was that a good deal of social interaction, collaboration and communication took place between the students when involved in communicative oral practice in Swedish. The students took almost optimal advantage of the allocated training time. They mostly used Swedish when participating in interactional communication. Finnish was mostly used by the students when they were deciding how to carry out a given task, aiming at intersubjectivity or negotiating meaning. The students were relaxed when practising Swedish. They also asked for and gave linguistic help in the spirit of collaborative learning principles. This resulted in interaction between students that highlighted certain features of negotiation of meaning, scaffolding and collaborative dialogue. Asking for and giving help in language issues concentrated mainly on vocabulary, and only in a few cases on grammar or pronunciation. The students also needed the teacher as a mentor. As well, the students had an enjoyable time when practising, which was most often related to carrying out the oral tasks. The thematic vocabulary used by the students corresponded well to the thematic lexis that served as a basis for the practice. At its most efficient, this lexis was most evident when the basic education students were carrying out schema-based tasks. The students' questionnaire answers agreed with the research findings gained through systematic observation and the analysis of audio recordings. The communicative tasks planned by the teacher and implemented by the students were very much in line. The language-didactic theory as presented in this study and the research findings can be widely utilised in pre-service and in-service teacher education, as well as, more generally, when developing communicative language teaching. Key words: communicative oral practice; the Swedish language; foreign language; didactic teaching-studying-learning process; communicative language teaching; collaborative task; schema-based task; elaboration task.

Kivaa ja hyödyllistä, mutta jo se riittää : Yläasteen kielikylpyoppilaiden käsityksiä ruotsinkielisestä kielikylpyopetuksesta Helsingissä

The aim of this study was to find out how immersion students experience immersion education, how they feel about the implementation of immersion education methods and what role immersion plays in immersion students’ lives outside the school context. In addition, the influence of sex, grade level, school and type of immersion education on students’ perceptions was studied. The population included all students at the lower secondary level in Helsinki who participated in Swedish immersion education during 2002–2003. The sample consisted of 128 students who represented two different forms of immersion: 47% of the students had previously participated in early total immersion while 53 % of the students had taken part in early partial immersion. The data were gathered through a questionnaire and interviews. All 128 students answered the questionnaire, and 10 students were chosen to focus interviews through purposive sampling. In addition, students’ parents were invited to fill in a questionnaire where students’ background information was requested. The data were collected during the spring of 2003. Principal Component Analysis and one-way variance analysis were used as statistical analysis methods. Also frequencies, average, correlations and cross tabs were studied. In the PCA a right-angled varimax-rotation was performed separately to every thematic entity that arose from the theoretical background. Sum variables were formed from the Principal Components by summing up all the items that received over .400 charges for the specific Principal Component. Significance testing of the mean was performed with F and t-tests. Results indicate that immersion students in lower secondary school experience immersion quite diversely as a whole. Students are satisfied with the fact that they are in the immersion class but not with the amount of teaching in Swedish. Students feel it is very important and useful to learn Swedish bearing in mind their future studies and working life. The students estimate their language skills to be very high. Yet they prefer using Finnish during classes. The fact that teachers use Swedish does not considerably affect how well the students learn the factual content in various subjects, especially if the student knows Swedish well. Theoretical subjects seemed to cause most problems. Swedish played only a very small part in students’ lives outside the school context and it was used merely when travelling abroad and in different kinds of guiding situations. Unless the students were talked to in Swedish, they kept on speaking Finnish. When asked about students’ experiences no statistically significant differences between sexes were found in this study. On the contrary, in some cases their grade level but especially their school and form of immersion had clear statistically significant differences on students’ perceptions.

Oikein, nurin - miten Suomessa kudin : Tutkimus neulonnan työotteista.

The aim of this work was to study what kind of working grips people use to knit in Finland and decide if one grip is superior to others. I investigated how knitters have adopted their grips and how they experience their knitting. I also explored whether it is possible to change one's grip. To provide a theoretical basis for the research I observed knitting in terms of culture, skill and ergonomics. The first part of the study material comprised video recordings of the grips of 95 knitters together with background information collected via a questionnaire during the education of craft teachers at the University of Helsinki in spring 2004, 2005 and 2006. Using the data obtained I focused on three knitters, whose grip of the knitting needles clearly differed from the ergonomically good grip. In addition to them I interviewed one student, who had changed over to more ergonomic way of knitting after participating in the first part of this study. In this respect my study is a several events' case study. In order to analyse my data I used both qualitative and quantitative content analysis methods to complement each other. Most of my research participants had learned to knit in first years of elementary school or comprehensive school. Almost everyone had adopted the basics of knitting by imitating, and many of them had corrected "incorrect" positions from verbal instructions. Through practice the imitated position had gradually become the style unique to each knitter. The findings showed that students' background in knitting is quite varied due to the diverse level of craft teaching. This is reflected in their knitting grips and their interest in knitting. Students do not think that there is one right working grip. The most important thing is that working seems as fluent and relaxed as possible, at which point knitting is easy and flows freely. They often consider their own style so pleasing and well-functioning that they do not think there could be any room for improvement. This study pointed out that, while it is possible to change a knitter's working grip, there is a bigger challenge in acknowledging weaknesses in one's know how. According to the results of my research, the most common working grip among Finnish knitters' corresponds with the grip that has been described as ergonomically good. Over one third of all participants knitted this way. Hands keep the knitting firmly but without tension. The forefinger that guides the yarn from the ball rests gently against the knitting needle, and the yarn goes in front of the first joint of the forefinger. The position of the hands and loops is the same as in the ergonomically good grip, i.e. the fingertips of both hands and the loops are near the tips of the knitting needles, so that the fingers only have to move small distances. When knitters purl and plain, they commonly pick up the yarn from the back of the knitting needle in the same way as when knitting. While researching the common features of working grips I have learned what abnormal grips are like. Although I recognized many different ways to knit, all the peculiar grips were modifications of the continental way of knitting. The results of this study give a clear picture of those points knitters should focus their attention on in order to gain a good hold of the needles.

Thermoanalysis of ammonium perchlorate and sodium nitrate mixture

A binary mixture of ammonium perchlorate-sodium nitrate in molar proportion undergoes partial fusion at 223°C and the transformation of the mixture to sodium perchlorate-ammonium nitrate occurs in the broad endothermic region. The mixture was heated and quenched at various temperatures in a differential thermal analysis assembly. Thermogravimetric analysis, X-ray diffraction, and infrared spectroscopic techniques were used to determine the composition of the quenched sample in order to explain the overall thermal phenomenon. Visual observations of the morphological changes that occur during the course of heating were made using a hot-stage microscope, 30–350°C.