Effect of supplemental vitamin E on the performance of growing-finishing pigs fed stored versus freshly harvested barley and on the storage stability and eating quality of frozen pork

Lihasikojen E-vitamiinin tarve ruokittaessa vastapuidulla ohralla ja rehuun lisätyn E-vitamiinin vaikutus lihan pakastussäilyvyyteen ja syöntilaatuun

Stability Evaluation of a Paper Machine Wet End

Työssä analysoidaanprosessin vaikutusta paperikoneen stabiiliuteen. Kaksi modernia sanomalehtipaperikonetta analysoitiin ja sen perusteella molemmista prosesseista rakennettiin fysiikan lakeihin perustuvat simulointimallit APROS Paper simulointiohjelmistolla. Työn tavoitteena on selvittää, miten kyseisten koneiden prosessit eroavat toisistaan ja arvioida, miten havaitut erot vaikuttavat prosessien stabiiliuteen. Työssä tarkastellaan periodisten häiriöiden vaimenemista prosessissa. Simuloinnissa herätteenä käytettiin puhdasta valkoista kohinaa, jonka avulla eri taajuistenperiodisten häiriöiden vaimenemista analysoitiin. Prosessien häiriövasteet esitetään taajuuskoordinaatistossa. Suurimmat erot prosessien välillä löytyivät viirakaivosta ja sen sekoitusdynamiikasta. Perinteisen viirakaivon todettiin muistuttavan käyttäytymiseltään sarjaan kytkettyjä ideaalisekoittimia, kun taas pienempitilavuuksisen fluumin todettiin käyttäytyvän lähes kuin putkiviive. Vaikka erotprosessitilavuudessa sekä viirakaivon sekoitusdynamiikassa olivat hyvin selkeät, havaittiin vain marginaalinen ero prosessin välillä periodisten häiriöiden vaimenemisessa, koska erot viiraretentiotasoissa vaikuttivat eniten simulointituloksia. Matalammalla viiraretentiolla operoivan paperikoneen todettiin vaimentavan tehokkaammin prosessihäiriöitä. Samalla retentiotasolla pienempitilavuuksisen prosessin todettiin vaimentavan hitaita prosessihäiriöitä marginaalisesti paremmin. Tutkituista paperikoneista toisella simuloitiin viiraosan vedenpoistomuutoksenvaikutusta viiraretentioon ja paperin koostumukseen. Lisäksi arvioitiin viiraretention säädön toimivuutta. Viiraosan listakengän vedenpoiston todettiin aiheuttavan merkittäviä sakeus- ja retentiohäiriöitä, mikäli sen avulla poistettavan kiintoaineen virtaus tuplaantuisi. Viiraretention säädön todettiin estävän häiriöiden kierron prosessissa, mutta siirtävän ne suoraan rainaan. Retention säädön eikuitenkaan todettu olevan suoranainen häiriön lähde.

Biocide analysis, usability and stability

Biosidien toimittajat tavallisesti suorittavat biosidien annostelumäärien hallinnan paperi- ja kartonkiteollisuudessa. Useimmiten annostelun hallinta määritetään epäsuorilla menetelmillä, kuten esimerkiksi määrittämällä bakteerien kasvua. Biosidien tehoaineiden todellista konsentraatiota tai määrää prosessivesissä tai lopputuotteessa ei tavallisesti mitata. Diplomityössä kehitettiin kolmelle paperiteollisuudessa yleisesti käytetyllä biosidin tehoaineelle analyyttiset menetelmät. Menetelmät kehitettiin glutaraldehydille, 2,2-dibromi-3-nitriilipropionamidi:lle (DBNPA) ja 5-kloori-2-metyyli-4-isotiatsoliini-3-oni:lle (CMI). Kehitettyjä menetelmiä käytettiin tehoaineiden stabiilisuuden seuraamiseen vesiliuoksessa eri pH:ssa ja lämpötilassa. Lisäksi kartonkinäytteistä tehtiin uuttokokeita ja yritettiin kehittää uuttomenetelmät, joilla pystyttäisiin määrittämään biosidien tehoaineiden jäännöspitoisuuksia lopputuotteesta. Glutaraldehydille ja CMI:lle onnistuttiin kehittämään uuttomenetelmät, joilla pystyttiin määrittämään kartongista tutkittujen tehoaineiden jäännöspitoisuudet. Saadut tulokset vaikuttavat realistisilta. Glutaraldehydille ja DBNPA:lle tehtiin stabiilisuuskokeita ja tulokset ovat samankaltaisia mitä muut tutkijat ovat saaneet.

Neurofilament proteins in the postnatal rat hippocampus. Developmental expression and changes in experimental epilepsy

Neurofilament proteins (NFs) are the major components of the intermediate filaments of the neuronal cytoskeleton. The three different NF proteins; the low (NF-L), medium (NF-M),and dendrites.NF proteins play an important role in neuronal development, and plasticity,and seem to contribute to the pathophysiology of several diseases. However, the detailed expression patterns of NF proteins in the course of postnatal aturation, and in response to seizures in the rat have remained unknown. In this work, I have studied the developmental expression and cellular distribution of the three NF proteins in the rat hippocampus during the postnatal development. The reactivity of NF proteins in response to kainic acid (KA)-induced status epilepticus (SE)was studied in the hippocampus of 9-day-old rats, and using in vitro organotypic hippocampal slices cultures prepared from P6-7 rats. The results showed that NF-L and NF-M proteins are expressed already at the postnatal day 1, while the expression of NF-H mainly occurred during the second postnatal week. The immunoreactivity of NF proteins varied depending on the cell type and sub-cellular location in the hippocampus. In adult rats, KA-induced SE typically results in severe and permanent NF degradation. However, in our P9 rats KA-induced SE resulted in a transient increase in the expression of NF proteins during the first few hours but not degradation. No neuronal death or mossy fiber sprouting was observed at any time after SE. The in vitro studies with OHCs, which mimick the in vivo developing models where a local injection of KA is applied(e.g. intrahippocampal), indicated that NF proteins were rapidly degraded in response to KA treatment, this effect being effectively inhibited by the treatment with the AMPA receptor antagonist CNQX, and calpain inhibitor MDL-28170. These compounds also significantly ameliorated the KA-induced region-specific neuronal damage. The NMDA receptor antagonist and the L-type Ca2+ channel blocker did not have any significant effect. In conclusion, the results indicate that the developmental expression of NF in the rat hippocampus is differentially regulated and targeted in the different hippocampal cell types during the postnatal development. Furthermore, despite SE, the mechanisms leading to NF degradation and neuronal death are not activated in P9 rats unlike in adults. The reason for this remains unknown. The results in organotypic hippocampal cultures confirm the validity of this in vitro model to study development processes, and to perform pharmacological studies. The results also suggest that calpain proteases as interesting pharmacological targets to reduce neuronal damage after acute excitotoxic insults.

The effect of microfibrillated cellulose addition on drying shrinkage and dimensional stability of wood-free paper

Microfibrillated cellulose (MFC) is known to enhance strength properties of paper. Improved strength usually means increased bonding which is strongly connected to dimensional instability of paper. Dimensional instability is due to changes in moisture content of paper; when paper is moistened it expands and when dried, it shrinks. Hygroexpansion is linked to end-use problems and excessive drying shrinkage consumes strength potential. Effective use of materials requires controlling of these phenomena. There isn’t yet data concerning dimensional stability of papers containing MFC which restricts wider use of MFC. Main objective of the work was to evaluate dimensional stability of wood-free paper containing different amounts of MFC. Sheets were dried with different methods to see how drying strains effected on drying shrinkage and hygroexpansion. Also tensile strength was measured to find out the effect of MFC. Results were compared to sheets containing kraft fines and in some test points cationic starch was used alongside with MFC. MFC increased the dimensional instability of freely dried sheets. As the amounts of MFC increased the effects on dimensional stability became more severe. However the fineness of MFC didn’t play any important role. Both hygroexpansion and drying shrinkage were decreased with cationic starch addition. Prevention of drying shrinkage over powered the effects of additives on hygroexpansion. Tensile strength improved up till 7 % addition amount which could be set as the upper limit of MFC addition when paper preparation and tensile strength are concerned.

Analysis and Control of Excitation, Field Weakening and Stability in Direct Torque Controlled Electrically Excited Synchronous Motor Drives

Direct torque control (DTC) is a new control method for rotating field electrical machines. DTC controls directly the motor stator flux linkage with the stator voltage, and no stator current controllers are used. With the DTC method very good torque dynamics can be achieved. Until now, DTC has been applied to asynchronous motor drives. The purpose of this work is to analyse the applicability of DTC to electrically excited synchronous motor drives. Compared with asynchronous motor drives, electrically excited synchronous motor drives require an additional control for the rotor field current. The field current control is called excitation control in this study. The dependence of the static and dynamic performance of DTC synchronous motor drives on the excitation control has been analysed and a straightforward excitation control method has been developed and tested. In the field weakening range the stator flux linkage modulus must be reduced in order to keep the electro motive force of the synchronous motor smaller than the stator voltage and in order to maintain a sufficient voltage reserve. The dynamic performance of the DTC synchronous motor drive depends on the stator flux linkage modulus. Another important factor for the dynamic performance in the field weakening range is the excitation control. The field weakening analysis considers both dependencies. A modified excitation control method, which maximises the dynamic performance in the field weakening range, has been developed. In synchronous motor drives the load angle must be kept in a stabile working area in order to avoid loss of synchronism. The traditional vector control methods allow to adjust the load angle of the synchronous motor directly by the stator current control. In the DTC synchronous motor drive the load angle is not a directly controllable variable, but it is formed freely according to the motor’s electromagnetic state and load. The load angle can be limited indirectly by limiting the torque reference. This method is however parameter sensitive and requires a safety margin between the theoretical torque maximum and the actual torque limit. The DTC modulation principle allows however a direct load angle adjustment without any current control. In this work a direct load angle control method has been developed. The method keeps the drive stabile and allows the maximal utilisation of the drive without a safety margin in the torque limitation.

Pencil grip : a descriptive model and four empirical studies

Previous studies on pencil grip have typically dealt with the developmental aspects in young children while handwriting research is mainly concerned with speed and legibility. Studies linking these areas are few. Evaluation of the existing pencil grip studies is hampered by methodological inconsistencies. The operational definitions of pencil grip arerational but tend to be oversimplified while detailed descriptors tend to be impractical due to their multiplicity. The present study introduces a descriptive two-dimensional model for the categorisation of pencil grip suitable for research applications in a classroom setting. The model is used in four empirical studies of children during the first six years of writing instruction. Study 1 describes the pencil grips observed in a large group of pupils in Finland (n = 504). The results indicate that in Finland the majority of grips resemble the traditional dynamic tripod grip. Significant genderrelated differences in pencil grip were observed. Study 2 is a longitudinal exploration of grip stability vs. change (n = 117). Both expected and unexpected changes were observed in about 25 per cent of the children's grips over four years. A new finding emerged using the present model for categorisation: whereas pencil grips would change, either in terms of ease of grip manipulation or grip configuration, no instances were found where a grip would have changed concurrently on both dimensions. Study 3 is a cross-cultural comparison of grips observed in Finland and the USA (n = 793). The distribution of the pencil grips observed in the American pupils was significantly different from those found in Finland. The cross-cultural disparity is most likely related to the differences in the onset of writing instruction. The differences between the boys' and girls' grips in the American group were non-significant.An implication of Studies 2 and 3 is that the initial pencil grip is of foremost importance since pencil grips are largely stable over time. Study 4 connects the pencil grips to assessment of the mechanics of writing (n = 61). It seems that certain previously not recommended pencil grips might nevertheless be includedamong those accepted since they did not appear to hamper either fluency or legibility.