The improvement of enclosure protection class of power electronics device

Tässä diplomityössä tutkittiin vaihtoehtoja tehoelektroniikkalaitteiden kotelointiluokan kehittämiseksi. Haasteena paremman suojauksen suunnittelussa on laitteiden tuottama suuri määrä lämpöä, joka vaatii tehokkaan jäähdytyksen. Työn tuloksena saatu prototyyppi IP33 luokkaa varten täyttää standardissa SFS-EN 60529+A1 asetetut vaatimukset kyseiselle kotelointiluokalle. Rakenteessa ja valmistettavuudessa havaittiin muutama ongelma, jotka ovat korjattavissa pienillä muutoksilla. Korkeampia suojausluokkia varten testattiin IP54-luokiteltujen filtterituulettimien vaikutusta laitteen jäähdytykseen. Testien perusteella jäähdytysteho on riittävä ja filtterituulettimet todettiin toimivaksi ratkaisuksi korkeammille suojausluokille. Työn perusteella voidaan todeta, että nykyiset laitteet voidaan muokata vastaamaan IP33 luokan vaatimuksia kohtuullisen pienillä muutoksilla. Tätä korkeammat suojausluokat vaatisivat niin suuria muutoksia designiin, että todennäköisesti täysin uuden laitteen suunnittelu olis kannattavin vaihtoehto.

Physiological, morphological and biochemical characteristics of the sexual propagation of Piper aduncum (Piperaceae)

In this work we attempted to characterize the diaspores and the germination process of Piper aduncum L., as well as to verify the influence of the interaction between presence and absence of light (photoperiod of 12 hours and dark) and temperature (25 °C, 30 °C and 20-30 °C) and also of gibberellin (0, 50, 100, 200 and 400 mg L-1) on the root protrusion and normal seedlings formation. The diaspores are very small with a thousand seed weight of 0.3645 g, 13% moisture and protein reserve. Diaspores are strict positively photoblastic in the tested temperature range and the optimum temperature for root protrusion was 30 °C, while for normal seedlings was 25 °C. The previous permanence in the dark led to an increase in the speed of root protrusion and percentage and speed of seedling formation. The application of gibberellic acid negatively interfered with the protrusion and growth of the radicle while favoring the elongation of hypocotyls.

Molecular characteristics of Machado-Joseph disease mutation in 25 newly described Brazilian families

Machado-Joseph disease (MJD) is a form of autosomal dominant spinocerebellar ataxia first described in North-American patients originating from the Portuguese islands of the Azores. Clinically this disorder is characterized by late onset progressive ataxia with associated features, such as: ophthalmoplegia, pyramidal and extrapyramidal signs and distal muscular atrophies. The causative mutation is an expansion of a CAG repeat in the coding region of the MJD1 gene. We have identified 25 unrelated families segregating the MJD mutation during a large collaborative study of spinocerebellar ataxias in Brazil. In the present study a total of 62 family members were genotyped for the CAG repeat in the MJD1 gene, as well as 63 non-MJD individuals (126 normal chromosomes), used as normal controls. We observed a wide gap between the size range of the normal and expanded CAG repeats: the normal allele had from 12 to 33 CAGs (mean = 23 CAGs), whereas the expanded alleles ranged from 66 to 78 CAGs (mean = 71.5 CAGs). There were no differences in CAG tract length according to gender of affected individuals or transmitting parent. We observed a significant negative correlation between age at onset of the disease and length of the CAG tract in the expended allele (r = -0.6, P = 0.00006); however, the size of the expanded CAG repeat could explain only about 40% of the variability in age at onset (r2 = 0.4). There was instability of the expanded CAG tract during transmission from parent to offspring, both expansions and contractions were observed; however, there was an overall tendency for expansion, with a mean increase of +2.4 CAGs. The tendency for expansion appeared to the greater in paternal (mean increase of +3.5 CAGs) than in maternal transmissions (mean increase of +1.3 CAGs). Anticipation was observed in all transmissions in which ages at onset for parent and offspring were known; however, anticipation was not always associated with an increase in the expanded CAG repeat length. Our results indicate that the molecular diagnosis of MJD can be confirmed or excluded in all suspected individuals, since alleles of intermediary size were not observed.

Characteristics of urban heat island (UHI) in a high latitude coastal city - a case study of Turku, SW Finland

The term urban heat island (UHI) refers to the common situation in which the city is warmer than its rural surroundings. In this dissertation, the local climate, and especially the UHI, of the coastal city of Turku (182,000 inh.), SW Finland, was studied in different spatial and temporal scales. The crucial aim was to sort out the urban, topographical and water body impact on temperatures at different seasons and times of the day. In addition, the impact of weather on spatiotemporal temperature differences was studied. The relative importance of environmental factors was estimated with different modelling approaches and a large number of explanatory variables with various spatial scales. The city centre is the warmest place in the Turku area. Temperature excess relative to the coldest sites, i.e. rural areas about 10 kilometers to the NE from the centre, is on average 2 °C. Occasionally, the UHI intensity can be even 10 °C. The UHI does not prevail continuously in the Turku area, but occasionally the city centre can be colder than its surroundings. Then the term urban cool island or urban cold island (UCI) is used. The UCI is most common in daytime in spring and in summer, whereas during winter the UHI prevails throughout the day. On average, the spatial temperature differences are largest in summer, whereas the single extreme values are often observed in winter. The seasonally varying sea temperature causes the shift of relatively warm areas towards the coast in autumn and inland in spring. In the long term, urban land use was concluded to be the most important factor causing spatial temperature differences in the Turku area. The impact was mainly a warming one. The impact of water bodies was emphasised in spring and autumn, when the water temperature was relatively cold and warm, respectively. The impact of topography was on average the weakest, and was seen mainly in proneness of relatively low-lying places for cold air drainage during night-time. During inversions, however, the impact of topography was emphasised, occasionally outperforming those of urban land use and water bodies.

An optically coupled power stimulus isolation unit with high voltage and fast rise time output

Recent technological developments have created new devices that could improve and simplify the construction of stimulus isolators. HEXFET transistors can switch large currents and hundreds of volts in nanoseconds. The newer opto-isolators can give a pulse rise time of a few nanoseconds, with output compatible with MOSFET devices, in which delays are reduced to nanoseconds. Integrated DC/DC converters are now available. Using these new resources we developed a new electrical stimulus isolator circuit with selectable constant-current and constant-voltage modes, which are precise and easy to construct. The circuit works like a regulated power supply in both modes with output switched to zero or to free mode through an opto-isolator device. The isolator analyses showed good practical performance. The output to ground resistance was 1011 ohms and capacitance 35 picofarads. The rise time and fall time were identical (5 µs) and constant. The selectable voltage or current output mode made it very convenient to use. The current mode, with higher output resistance values in low current ranges, permits intracellular stimulation even with tip resistances close to 100 megaohms. The high compliance of 200 V guarantees the value of the current stimulus. The very low output resistance in the voltage mode made the device highly suitable for extracellular stimulation with low impedance electrodes. Most importantly, these characteristics were achieved with a circuit that was easy to build and modify and assembled with components available in Brazil.

Biophysical characteristics of gap junctions in vascular wall cells: implications for vascular biology and disease

The role gap junction channels play in the normal and abnormal functioning of the vascular wall is the subject of much research. The biophysical properties of gap junctions are an essential component in understanding how gap junctions function to allow coordinated relaxation and contraction of vascular smooth muscle. This study reviews the properties thus far elucidated and relates those properties to tissue function. We ask how biophysical and structural properties such as gating, permselectivity, subconductive states and channel type (heteromeric vs homotypic vs heterotypic) might affect vascular smooth muscle tone.

Private Equity Fund Performance Determinants: Evidence From Fund Characteristics

The purpose of this thesis is to investigate whether different private equity fund characteristics have any influence on the fund performance. Fund characteristics include fund type (venture capital or buyouts), fund size (sizes of funds are divided into six ranges), fund investment industry, fund sequence (first fund or follow-on fund) and investment market (US or EMEA). Fund performance is measured by internal rate of return, and tested by cross-sectional regression analysis with the method of Ordinary Least Squares. The data employs performance and characteristics of 997 private equity funds between 1985 and 2008. Our findings are that fund type has effect on fund performance. The average IRR of venture capital funds is 2.7% less than average IRR of buyout funds. However, We did not find any relationship between fund size and performance, and between fund sequence and performance. Funds based on US market perform better than funds based on EMEA market. The fund performance differs across different industries. The average IRRs of industrial/energy industry, consumer related industry, communications and media industry and medical/health industry are higher than the average IRR of other industries.

Ravinnepitoisen teollisen jäteveden tuotteistaminen

Tässä työssä selvitettiin ravinnepitoisen jäteveden väkevöintiä erityisesti ammoniumtypen ja orgaanisten happojen osalta. Konsentrointiin käytettiin pääasiassa käänteisosmoosia sekä haihdutusta, mutta myös nanosuodatusta tutkittiin. Jätevesi oli Honkajoki Oy:n lauhdevettä. Kirjallisuusosassa esiteltiin Honkajoki Oy:n toimintaa, membraanierotus-prosesseja, lihantuotannossa syntyvän jätteen ominaisuuksia sekä sen puhdistamista. Keskeisimmät suodatukset tehtiin DOW FILMTEC SW30HR -membraanilla, ja käytetty laitteisto oli DSS LabStak M20. Suodatuksia tehtiin eri pH-olosuhteissa typen ja orgaanisten happojen erottumisen kannalta optimaalisten olosuhteiden löytämiseksi. Lisäksi tutkittiin, kuinka puhtaaksi permeaatti voidaan saada uudelleensuodatuksen avulla. Työssä käytettiin myös haihdutusta lauhteen väkevöintiin. Ammoniumtypen konsentroituminen suodatuksissa oli tehokkainta pH:n ollessa 7 tai sen alle. Kaksivaiheisella suodatuksella permeaatin laatu alitti selvästi Karvianjokeen laskettaville jätevesille asetetut laatu- ja kuormitusrajat. Yhdistämällä suodatus- ja haihdutusprosessit, pystyttiin valmistamaan liuosta, jonka ammoniumtyppipitoisuus oli noin 7,6 %. Tuolloin suodatus tehtiin pH 7:ssä ja haihdutus pH 3:ssa rotavaporilla 26 mbar paineessa ja 50 °C lämpötilassa. Syöttöliuoksen tilavuuden alenema oli noin 65-kertainen. Haihdutuksessa muodostuneessa lauhteessa oli paljon orgaanisia happoja ja käytännössä ei lainkaan ammoniumtyppeä. Tuotejakeita saatiin siten kaksi kappaletta: ammoniumtyppijae ja orgaanisia happoja sisältävä jae.

Behavioral characteristics of the offspring of adolescent rats

The aim of this study was to test the hypothesis that, during adulthood, the offspring of adolescent rats differ in emotionality, learning and memory from the offspring of adult rats. The behavior of the offspring of adolescent (age, 50-55 days) and adult rats (age, 90-95 days) was tested in the open field, activity cage, and passive and active avoidance apparatus. The latencies during training and testing in the passive avoidance apparatus of the offspring of adolescent parents were shorter than the latencies of control offspring (P<0.001 on both training and testing days). Offspring of adolescent parents showed shorter latency time in acquisition trials during active avoidance testing compared to control offspring (P<0.001). They also showed a higher number of active avoidance responses in the last four blocks of acquisition (P<0.001) and first two blocks of extinction trials (P<0.05 and P<0.001, respectively). The offspring of adolescent parents showed higher latency on the first day of testing in the open field (P<0.01) and a lower latency on the third day of testing (P<0.01). They also showed higher activity during all three days of testing (1st and 2nd day: P<0.01; 3rd day: P<0.05). The spontaneous activity of the offspring of adolescent parents in the activity cage was higher in the last three intervals of testing (P<0.001). In summary, the offspring of adolescent parents were less anxious and tended to be more active. The results of two learning and memory tests were opposite, but could be explained by a higher exploratory drive of the offspring of adolescent parents. This was probably due to chronic malnutrition stress and the disturbed mother-infant relationship in the litters of adolescent mothers.

Evaluation of two 99mTc-DTPA radioaerosols with different characteristics in lung ventilation studies

Two radioaerosol preparations, TechneScan®-DTPA (99mTc-DTPA, 40 mCi/3 ml; IPEN-CNEN, São Paulo, SP, Brazil) and TechneScan®-DTPA/AEROSOL (99mTc-DTPA/A, 15 mCi/1.5 ml with 0.5 ml ethanol; Mallinckrodt Medical, St. Louis, MO, USA), were compared in pulmonary ventilation studies in terms of total radiocounts and clearance after inhalation. An aerosol with ethanol is supposed to better distribute the radioparticles in the lungs. Twenty normal nonsmoking volunteers (10 men and 10 women), mean age of 23.2 years (range: 20 to 35 years), were studied. Images were obtained immediately and 30, 60 and 90 min after inhalation. Total and regional counts were obtained and the clearance half-lives of both lungs were determined. There was no difference in total counts between the two types of radioaerosol at any time (mean of ~188,000 cpm for male and female subjects at time zero in both aerosols). The highest count was obtained in the middle region of both lungs (P<0.001) with both preparations. The clearance half-life did not differ between aerosols (mean of ~80-88 min for male and female subjects for both aerosols). Small nonsignificant regional differences were observed. No differences between genders or between right and left lung were observed. 99mTc-DTPA/A generated the highest output of radioaerosol. 99mTc-DTPA with alcohol costs approximately five times more than the aerosol without alcohol. The present results show that either kind of aerosol may be adopted routinely for use in pulmonary examinations without affecting diagnosis. We suggest that the amount of 740 mBq (20 mCi) of 99mTc-DTPA in 1.5 ml saline can be used for routine examinations resulting in reduction of costs in pulmonary ventilation studies without diagnostic impairment.

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history

Preterm delivery is the main cause of neonatal death and ultrasonographic cervical assessment has been shown to be more accurate than digital examination in recognizing a short cervix. This is a cross-sectional study, involving 1131 women at 22-24 weeks of pregnancy, designed to determine the distribution of cervical length and to examine which variables of demographic characteristics and obstetric history increase the risk of a short cervix (15 mm or less). The distribution of maternal demographic and obstetric history characteristics among patients with cervical length £15 mm was analyzed and compared to the findings for the general population. Risk ratios (RR) between subgroups were generated from this comparison. Median cervical length was 37 mm and in 1.5% of cases it was 15 mm or less. The proportion of women with a short cervix (<=15 mm) was significantly higher among patients with a low body mass index (RR = 3.5) and in those with previous fetal losses between 16-23 weeks (RR = 33.1) or spontaneous preterm deliveries between 24-32 weeks (RR = 14.1). We suggest that transvaginal sonographic measurement of cervical length be performed as part of a routine midtrimester ultrasound evaluation. There are specific variables of demographic characteristics and obstetric history which increase the risk of detecting a short cervix at 22-24 weeks.

Towards sustainable transport: A comparison of demographic and behavioural characteristics of Finnish and international car sharing users

SStrong evidence suggests that the climate is changing and that these changes are largely caused by human activities. A consensus exists among researchers that human activity is causing global warming and that actions to mitigate global warming need to be taken swiftly. The transportation sector, which relies heavily on fossil fuel burning and primarily oil, is one of the big contributors to air pollution problems at local, regional and global levels. It is the fastest growing source of greenhouse gas emissions and is estimated to be responsible for nearly a quarter of global energyrelated carbon dioxide emissions. Car sharing is a mobility solution encouraging its users to decrease private car usage in favour of communal transit and environmental goals. The idea of car sharing originates from the aspiration to decrease personal car ownership and to reduce vehicle distance travelled. This thesis seeks to complement the understanding of Finnish car sharing users and their usage through better categorization. Through better categorization and segmentation of Finnish car sharing users the thesis seeks to provide information for improved marketing insight. Research is done on the demographic and behavioural characteristics of Finnish car sharing users and they are compared with international findings about the characteristics of International car sharing users. The main research problem is Are Finnish car sharing users similar to international ones? A theoretical research framework on the determinants of individual car sharing usage is built based on international research about demographic and behaviouristic characteristics. After this a quantitative survey is performed to the customers of a Finnish car sharing organization. The data analysed in the thesis consist out of 532 answers received from the car sharing organizations customers. The data is analysed with descriptive and other exploratory methods, which create an understanding of Finnish car sharing users. At the end of the analysis the demographic and behavioural characteristics of Finnish car sharing users are compared with international ones. The research findings of the thesis indicate that the demographic and behavioural characteristics of Finnish car sharing usage largely follow those of their international counterparts. Thanks to the thesis results the car sharing organization is able to better target their customers through improved marketing insight.

Histopathological characteristics of a novel knock-in mouse prostate cancer model

Prostate cancer is relatively unique to man. There is no naturally occurring prostate cancer in the mouse. Pre-clinical studies involve the establishment of a genetically engineered mouse prostate cancer model with features close to those of the human situation. A new knock-in mouse adenocarcinoma prostate (KIMAP) model was established, which showed close-to-human kinetics of tumor development. In order to determine if the similar kinetics is associated with heterogeneous tumor architecture similar to the human situation, we utilized a new mouse histological grading system (Gleason analogous grading system) similar to the Gleason human grading system and flow cytometry DNA analysis to measure and compare the adenocarcinoma of the KIMAP model with human prostate cancer. Sixty KIMAP prostate cancer samples from 60 mice were measured and compared with human prostate cancer. Flow cytometry DNA analysis was performed on malignant prostate tissues obtained from KIMAP models. Mice with prostate cancer from KIMAP models showed a 53.3% compound histological score rate, which was close to the human clinical average (50%) and showed a significant correlation with age (P = 0.001). Flow cytometry analyses demonstrated that most KIMAP tumor tissues were diploid, analogous to the human situation. The similarities of the KIMAP mouse model with tumors of the human prostate suggest the use of this experimental model to complement studies of human prostate cancer.

Computerized invasive measurement of time-dependent intraocular pressure

Several methods have been described to measure intraocular pressure (IOP) in clinical and research situations. However, the measurement of time varying IOP with high accuracy, mainly in situations that alter corneal properties, has not been reported until now. The present report describes a computerized system capable of recording the transitory variability of IOP, which is sufficiently sensitive to reliably measure ocular pulse peak-to-peak values. We also describe its characteristics and discuss its applicability to research and clinical studies. The device consists of a pressure transducer, a signal conditioning unit and an analog-to-digital converter coupled to a video acquisition board. A modified Cairns trabeculectomy was performed in 9 Oryctolagus cuniculus rabbits to obtain changes in IOP decay parameters and to evaluate the utility and sensitivity of the recording system. The device was effective for the study of kinetic parameters of IOP, such as decay pattern and ocular pulse waves due to cardiac and respiratory cycle rhythm. In addition, there was a significant increase of IOP versus time curve derivative when pre- and post-trabeculectomy recordings were compared. The present procedure excludes corneal thickness and error related to individual operator ability. Clinical complications due to saline infusion and pressure overload were not observed during biomicroscopic evaluation. Among the disadvantages of the procedure are the requirement of anesthesia and the use in acute recordings rather than chronic protocols. Finally, the method described may provide a reliable alternative for the study of ocular pressure dynamic alterations in man and may facilitate the investigation of the pathogenesis of glaucoma.

Weld joint characteristics by nano-materials addition

The need for industries to remain competitive in the welding business, has created necessity to develop innovative processes that can exceed customer’s demand. Significant development in improving weld efficiency, during the past decades, still have their drawbacks, specifically in the weld strength properties. The recent innovative technologies have created smallest possible solid material known as nanomaterial and their introduction in welding production has improved the weld strength properties and to overcome unstable microstructures in the weld. This study utilizes a qualitative research method, to elaborate the methods of introducing nanomaterial to the weldments and the characteristic of the welds produced by different welding processes. The study mainly focuses on changes in the microstructural formation and strength properties on the welded joint and also discusses those factors influencing such improvements, due to the addition of nanomaterials. The effect of nanomaterial addition in welding process modifies the physics of joining region, thereby, resulting in significant improvement in the strength properties, with stable microstructure in the weld. The addition of nanomaterials in the welding processes are, through coating on base metal, addition in filler metal and utilizing nanostructured base metal. However, due to its insignificant size, the addition of nanomaterials directly to the weld, would poses complications. The factors having major influence on the joint integrity are dispersion of nanomaterials, characteristics of the nanomaterials, quantity of nanomaterials and selection of nanomaterials. The addition of nanomaterials does not affect the fundamental properties and characteristics of base metals and the filler metal. However, in some cases, the addition of nanomaterials lead to the deterioration of the joint properties by unstable microstructural formations. Still research are ongoing to achieve high joint integrity, in various materials through different welding processes and also on other factors that influence the joint strength.