9 resultados para Materials testing
em Helda - Digital Repository of University of Helsinki
Resumo:
Solid materials can exist in different physical structures without a change in chemical composition. This phenomenon, known as polymorphism, has several implications on pharmaceutical development and manufacturing. Various solid forms of a drug can possess different physical and chemical properties, which may affect processing characteristics and stability, as well as the performance of a drug in the human body. Therefore, knowledge and control of the solid forms is fundamental to maintain safety and high quality of pharmaceuticals. During manufacture, harsh conditions can give rise to unexpected solid phase transformations and therefore change the behavior of the drug. Traditionally, pharmaceutical production has relied on time-consuming off-line analysis of production batches and finished products. This has led to poor understanding of processes and drug products. Therefore, new powerful methods that enable real time monitoring of pharmaceuticals during manufacturing processes are greatly needed. The aim of this thesis was to apply spectroscopic techniques to solid phase analysis within different stages of drug development and manufacturing, and thus, provide a molecular level insight into the behavior of active pharmaceutical ingredients (APIs) during processing. Applications to polymorph screening and different unit operations were developed and studied. A new approach to dissolution testing, which involves simultaneous measurement of drug concentration in the dissolution medium and in-situ solid phase analysis of the dissolving sample, was introduced and studied. Solid phase analysis was successfully performed during different stages, enabling a molecular level insight into the occurring phenomena. Near-infrared (NIR) spectroscopy was utilized in screening of polymorphs and processing-induced transformations (PITs). Polymorph screening was also studied with NIR and Raman spectroscopy in tandem. Quantitative solid phase analysis during fluidized bed drying was performed with in-line NIR and Raman spectroscopy and partial least squares (PLS) regression, and different dehydration mechanisms were studied using in-situ spectroscopy and partial least squares discriminant analysis (PLS-DA). In-situ solid phase analysis with Raman spectroscopy during dissolution testing enabled analysis of dissolution as a whole, and provided a scientific explanation for changes in the dissolution rate. It was concluded that the methods applied and studied provide better process understanding and knowledge of the drug products, and therefore, a way to achieve better quality.
Resumo:
Modifications of surface materials and their effects on cleanability have important impacts in many fields of activity. In this study the primary aim was to develop radiochemical methods suitable for evaluating cleanability in material research for different environments. Another aim was to investigate the effects of surface modifications on cleanabilitity and surface properties of plastics, ceramics, concrete materials and also their coatings in conditions simulating their typical environments. Several new 51Cr and 14C labelled soils were developed for testing situations. The new radiochemical methods developed were suitable for examining different surface materials and different soil types, providing quantitative information about the amount of soil on surfaces. They also take into account soil soaked into surfaces. The supporting methods colorimetric determination and ATP bioluminescence provided semi-quantitative results. The results from the radiochemical and supporting methods partly correlated with each other. From a material research point of view numerous new materials were evaluated. These included both laboratory-made model materials and commercial products. Increasing the amount of plasticizer decreased the cleanability of poly(vinyl chloride) (PVC) materials. Microstructured surfaces of plastics improved the cleanability of PVC from particle soils, whereas for oil soil microstructuring reduced the cleanability. In the case of glazed ceramic materials, coatings affected the cleanability. The roughness of surfaces correlated with cleanability from particle soils and the cleanability from oil soil correlated with the contact angles. Organic particle soil was removed more efficiently from TiO2-coated ceramic surfaces after UV-radiation than without UV treatment, whereas no effect was observed on the cleanability of oil soil. Coatings improved the cleanability of concrete flooring materials intended for use in animal houses.
Resumo:
The feasibility of different modern analytical techniques for the mass spectrometric detection of anabolic androgenic steroids (AAS) in human urine was examined in order to enhance the prevalent analytics and to find reasonable strategies for effective sports drug testing. A comparative study of the sensitivity and specificity between gas chromatography (GC) combined with low (LRMS) and high resolution mass spectrometry (HRMS) in screening of AAS was carried out with four metabolites of methandienone. Measurements were done in selected ion monitoring mode with HRMS using a mass resolution of 5000. With HRMS the detection limits were considerably lower than with LRMS, enabling detection of steroids at low 0.2-0.5 ng/ml levels. However, also with HRMS, the biological background hampered the detection of some steroids. The applicability of liquid-phase microextraction (LPME) was studied with metabolites of fluoxymesterone, 4-chlorodehydromethyltestosterone, stanozolol and danazol. Factors affecting the extraction process were studied and a novel LPME method with in-fiber silylation was developed and validated for GC/MS analysis of the danazol metabolite. The method allowed precise, selective and sensitive analysis of the metabolite and enabled simultaneous filtration, extraction, enrichment and derivatization of the analyte from urine without any other steps in sample preparation. Liquid chromatographic/tandem mass spectrometric (LC/MS/MS) methods utilizing electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) were developed and applied for detection of oxandrolone and metabolites of stanozolol and 4-chlorodehydromethyltestosterone in urine. All methods exhibited high sensitivity and specificity. ESI showed, however, the best applicability, and a LC/ESI-MS/MS method for routine screening of nine 17-alkyl-substituted AAS was thus developed enabling fast and precise measurement of all analytes with detection limits below 2 ng/ml. The potential of chemometrics to resolve complex GC/MS data was demonstrated with samples prepared for AAS screening. Acquired full scan spectral data (m/z 40-700) were processed by the OSCAR algorithm (Optimization by Stepwise Constraints of Alternating Regression). The deconvolution process was able to dig out from a GC/MS run more than the double number of components as compared with the number of visible chromatographic peaks. Severely overlapping components, as well as components hidden in the chromatographic background could be isolated successfully. All studied techniques proved to be useful analytical tools to improve detection of AAS in urine. Superiority of different procedures is, however, compound-dependent and different techniques complement each other.
Resumo:
The purpose of the research was to determine how well Finnish pupils and students of different ages recognize plant species, which variables explain recognition of plant species, what plants and nature mean to the subjects and how plant species identification should be taught in general education in Finland. The subjects were pupils from: every class level of the primary schools (grades 1 6); lower- secondary school (grades 7 9); high school (grades I II); university departments of teacher education and classroom teachers and teachers from university involved with environmental teaching and also experts from education and botany. A total of 883 people took part in the research. Both quantitative and qualitative research methods were used. The quantitative methods were: a) plant species recognition test, where 70 plant species photos were shown to subjects and b) an experiment in which three experimental groups had a plant recognition test on the nature trail and the three comparison groups were tested on recognition of the same species in classroom. The testing materials consisted of 31 real plants outdoors and 31 photos taken of these real plant species that were shown to pupils from fourth, fifth and sixth classes (grade levels) from primary school. The qualitative methods were a questionnaire administered to pupils from elementary school and high school and students from the department of teacher education, to teachers from university and interviews, where 3 5 pupils and students who recognized the plant species best or worst in the recognition test were selected to be interviewed. Furthermore, classroom teachers from primary school and experts were interviewed. The research results showed that on average plant species were recognized insufficiently on every level of education. There was also variation between answers from primary school to university teachers. However, species recognition skills improved from primary school to university teachers. Among other things, sex and place of residence explained species recognition skills, because girls and pupils from rural areas knew plant species statistically significantly better than boys or pupil from cities. Almost every pupil, student and all classroom teachers wanted to recognize plant species better. Many pupils mentioned that a motivating teaching method would be to go outdoors and investigate the plant species themselves. University teachers and experts also mentioned that the best and most efficient learning and teaching method for species recognition skills, is to practice in nature. We should teach plant species in nature, using many senses and teaching methods. Also new technology could be used in teaching species recognition skills. Keywords: plant species recognition, plant species education, general education
Resumo:
The aim of the thesis was to compare the correspondence of the outcome a computer assisted program appearance compared to the original image. The aspect of the study was directed to embroidery with household machines. The study was made from the usability point of view with Brother's PE-design 6.0 embroidery design programs two automatic techniques; multicoloured fragment design and multicoloured stitch surface design. The study's subject is very current because of the fast development of machine embroidery. The theory is based on history of household sewing machines, embroidery sewing machines, stitch types in household sewing machines, embroidery design programs as well as PE-design 6.0 embroidery design program's six automatic techniques. Additionally designing of embroidery designs were included: original image, digitizing, punching, applicable sewing threads as well as the connection between embroidery designs and materials used on embroidery. Correspondences of sewn appearances were examined with sewing experimental methods. 18 research samples of five original image were sewn with both techniques. Experiments were divided into four testing stages in design program. Every testing stage was followed by experimental sewing with Brother Super Galaxie 3100D embroidery machine. Experiments were reported into process files and forms made for the techniques. Research samples were analysed on images syntactic bases with sensory perception assessment. Original images and correspondence of the embroidery appearances were analysed with a form made of it. The form was divided into colour and shape assessment in five stage-similarity-scale. Based on this correspondence analysis it can be said that with both automatic techniques the best correspondence of colour and shape was achieved by changing the standard settings and using the makers own thread chart and edited original image. According to the testing made it is impossible to inform where the image editing possibilities of the images are sufficient or does the optimum correspondence need a separate program. When aiming at correspondence between appearances of two images the computer is unable to trace by itself the appearance of the original image. Processing a computer program assisted embroidery image human perception and personal decision making are unavoidable.
Resumo:
The purpose of the study was to develop a functional web-based learning material for the learning of the nålbinding technique. The study of the research topic was already begun in my pedagogical thesis in 2008 by considering the demands on pedagogic material for the teaching of the technique. This study falls into the field of qualitative design research which was carried out through three stages. In the study three methods of usability testing, i.e. expert analysis, the informants’ thinking aloud and interviews, were used as research methods. At the first stage of the study the first version of the learning material was created. This was done on the basis of theoretical knowledge, the demands set on learning materials as clarified in previous studies, on the basis of previously created learning materials for the learning of the nålbinding technique as well as with the help of two experts on the technique. At the second stage, the learning material was developed on the basis of expert analysis and another version of the material was created. At the third stage, usability testing was carried out on the material. At this stage two informants used the material, practiced stitching with the nålbinding needle and thought aloud while doing so. In the usability testing the Morae –programme was used to record the events on the screen, the actions of the informants and their spoken out thoughts. The Morae –programme was also used when analysing the recordings. After the testing, the informants practised stitching independently and in a few weeks time they were interviewed. The interviews were aimed at finding out the informants’ opinions on the future development of the material. On the basis of the informants’ independent attempts at using the nålbinding technique, the development of their skills after the testing was also discussed at the interviews. The development of the learning material will continue after this study on the basis of the usability testing and the interviews. The web-based learning material was created for the website Käspaikka in the address www.kaspaikka.fi/kinnasneula. By creating a multimodal learning material the dual-coding theory by Paivio was taken into consideration. According to the theory, several methods of presentation help a learner to restore information in his/her memory. The independent construction of the learner’s knowledge, i.e. learning according to the principles of the constructivist learning theory, was also supported by creating a logical navigation system, by linking interrelated topics to one another and by presenting the topics in several different forms. In the test situations the learning material was judged to work well when practising stitching with the nålbinding needle. Both informants learned the basics of the nålbinding technique even though their respective learning strategies were quite different. In the usability testing illogicalities and shortcomings were still noticed in the learning material which will still be further developed in the future.
Design and testing of stand-specific bucking instructions for use on modern cut-to-length harvesters
Resumo:
This study addresses three important issues in tree bucking optimization in the context of cut-to-length harvesting. (1) Would the fit between the log demand and log output distributions be better if the price and/or demand matrices controlling the bucking decisions on modern cut-to-length harvesters were adjusted to the unique conditions of each individual stand? (2) In what ways can we generate stand and product specific price and demand matrices? (3) What alternatives do we have to measure the fit between the log demand and log output distributions, and what would be an ideal goodness-of-fit measure? Three iterative search systems were developed for seeking stand-specific price and demand matrix sets: (1) A fuzzy logic control system for calibrating the price matrix of one log product for one stand at a time (the stand-level one-product approach); (2) a genetic algorithm system for adjusting the price matrices of one log product in parallel for several stands (the forest-level one-product approach); and (3) a genetic algorithm system for dividing the overall demand matrix of each of the several log products into stand-specific sub-demands simultaneously for several stands and products (the forest-level multi-product approach). The stem material used for testing the performance of the stand-specific price and demand matrices against that of the reference matrices was comprised of 9 155 Norway spruce (Picea abies (L.) Karst.) sawlog stems gathered by harvesters from 15 mature spruce-dominated stands in southern Finland. The reference price and demand matrices were either direct copies or slightly modified versions of those used by two Finnish sawmilling companies. Two types of stand-specific bucking matrices were compiled for each log product. One was from the harvester-collected stem profiles and the other was from the pre-harvest inventory data. Four goodness-of-fit measures were analyzed for their appropriateness in determining the similarity between the log demand and log output distributions: (1) the apportionment degree (index), (2) the chi-square statistic, (3) Laspeyres quantity index, and (4) the price-weighted apportionment degree. The study confirmed that any improvement in the fit between the log demand and log output distributions can only be realized at the expense of log volumes produced. Stand-level pre-control of price matrices was found to be advantageous, provided the control is done with perfect stem data. Forest-level pre-control of price matrices resulted in no improvement in the cumulative apportionment degree. Cutting stands under the control of stand-specific demand matrices yielded a better total fit between the demand and output matrices at the forest level than was obtained by cutting each stand with non-stand-specific reference matrices. The theoretical and experimental analyses suggest that none of the three alternative goodness-of-fit measures clearly outperforms the traditional apportionment degree measure. Keywords: harvesting, tree bucking optimization, simulation, fuzzy control, genetic algorithms, goodness-of-fit