Lujien painelaiteterästen hitsaus

Työn tavoitteena oli tutkia lujan nuorrutetun painelaiteteräksen P500QL2 hitsattavuutta ja koehitsausten avulla löytää optimaaliset hitsausparametrit ja lämmöntuonti teräksen hitsaukseen. Työn tavoitteena oli myös selvittää ja käsitellä kaikkien painelaiteterässtandardissa esitettyjen lujien painelaiteterästen hitsauksessa huomioon otettavia asioita. Työn teoriaosuudessa käsitellään lujien painelaiteterästen hitsauksessa huomioitavia erityispiirteitä, kuten lämmöntuontia, jäähtymisaikaa, esilämmitystä sekä hitsausaineiden valintaa. Lisäksi teoriaosuudessa käsitellään painelaitteiden valmistusta, painelaiteterässtandardiin kuuluvia lujia painelaiteteräksiä sekä keinoja lujien terästen hitsattavuuden arviointiin. Työn kokeellisessa osassa tutkittiin aineenvahvuudeltaan 50 mm paksun P500QL2-teräksen päittäisliitoksen mekaanisia ominaisuuksia eri lämmöntuonneilla hitsattuna. Kokeellisessa osassa tutkittiin myös myöstön poisjättämisen vaikutuksia liitoksen mekaanisiin ominaisuuksiin. Mekaanisia ominaisuuksia tutkittiin toteuttamalla koekappaleiden aineenkoetus menetelmäkoestandardin vaatimuksia soveltaen. Tutkimuksessa käytettyjä testausmenetelmiä olivat silmämääräinen tarkastus, magneettijauhetarkastus, ultraäänitarkastus, mikro- ja makrorakennetarkastelu, kovuuskokeet, vetokokeeet ja iskukokeet. Testauksessa saatujen tulosten avulla lujan painelaiteteräksen P500QL2 hitsaukseen laadittiin alustava hitsausohje. Hitsausliitosten testauksessa saatujen tulosten perusteella havaittiin hitsien lujuuden ja kovuuden laskevan lämmöntuonnin kasvaessa. Hitsausliitosten iskusitkeysominaisuudet olivat erinomaiset vielä suurellakin lämmöntuonnilla, mutta liitosten murtovenymäarvot laskivat lämmöntuonnin kasvaessa. Myöstön havaittiin parantavan hitsin mekaanisia ominaisuuksia huomattavasti. Tutkimuksen tulosten perusteella painelaiteteräs P500QL2 on hitsattavissa suurella lämmöntuonnilla ja suurella tuottavuudella liitoksen täyttäessä painelaitevalmistuksen edellyttämät vaatimukset.

Osuman havaitsevan maalilaitteen anturointi

Työssä tutkittiin anturointimahdollisuuksia havaita ammutun luodin osuminen maalitauluun ja mitata helposti saatavilla olevia passiivisia antureita. Luodin osuminen maalitauluun luo muutoksia maalilaitteessa ja maalitaulussa. Nämä voidaan havaita kiihtyvyytenä, äänenä tai muutoksena maalitaulussa.

Talousvesilaitoksen saostusvaiheen tehostaminen esihapetuksella – Case Suomen Sokeri Oy:n vedenkäsittely

Diplomityö tehtiin Suomen Sokeri Oy:n vesilaitokselle Vihreän Kemian laboratoriossa. Prosessia tarkasteltiin saostuksen osalta ja tavoitteena oli sen kehittäminen esihapetusmenetelmän tai saostuskemikaalin vaihdon avulla. Tarkastelu tehtiin orgaanisen, kiintoaineksen ja metallien poiston, desinfiointitehon sekä ympäristöystävällisyyden osalta. Potentiaalisia esihapetusmenetelmiä (kaliumpermanganaatti, vetyperoksidi, valokemiallinen, H2O2/UV, valokatalyyttinen, TiO2/UV, H2O2/ultraääni sekä esihapetus peretikkahapolla) tarkasteltiin eri pitoisuuksilla ja tehoilla laboratoriomittakaavassa jar-testin avulla. Saostustehoa testattiin alumiinikloridilla ja ferrisulfaatilla. Raakaveden laadun muutoksia eri vaiheissa seurattiin laboratorioanalyysein. Hapetusmenetelmien desinfiointiteho, vaikutukset syanobakteereihin ja -toksiineihin sekä reaktioissa syntyvät sivutuotteet kartoitettiin teorian perusteella. Työn tuloksien perusteella kaliumpermanganatti, vetyperoksidi erityisesti kehittyneenä hapetustekniikkana sekä valokatalyyttinen menetelmä tehostivat vedenkäsittelyä, mutta koska TiO2/UV- tai ultraäänihapetukselle ei ole vielä olemassa kaupallista sovellusta laitosmittakaavassa niin suositeltavat menetelmät ovat KMnO4- ja H2O2(/UV)-hapetukset jatkotutkimussuositukset huomioiden. Peretikkahappo ei tämän tutkimuksen perusteella vaikuttanut suositeltavalta hapetusmenetelmältä, mutta sen sijaan teorian perusteella potentiaaliselta desinfektioaineelta myös talousvedenpuhdistukseen. Opinnäytetyötä eri hapetusmenetelmien osalta talousvedelle ei ole aiemmin tehty eikä peretikkahappohapetuksesta ole laajalti aiempaa tutkimustietoa. Kokeellisen osuuden tulokset antavat uutta tietoa menetelmien soveltuvuudesta vastaaville laitoksille.

Validation of transit-time flowmetry for chronic measurements of regional blood flow in resting and exercising rats

The objective of the present study was to validate the transit-time technique for long-term measurements of iliac and renal blood flow in rats. Flow measured with ultrasonic probes was confirmed ex vivo using excised arteries perfused at varying flow rates. An implanted 1-mm probe reproduced with accuracy different patterns of flow relative to pressure in freely moving rats and accurately quantitated the resting iliac flow value (on average 10.43 ± 0.99 ml/min or 2.78 ± 0.3 ml min-1 100 g body weight-1). The measurements were stable over an experimental period of one week but were affected by probe size (resting flows were underestimated by 57% with a 2-mm probe when compared with a 1-mm probe) and by anesthesia (in the same rats, iliac flow was reduced by 50-60% when compared to the conscious state). Instantaneous changes of iliac and renal flow during exercise and recovery were accurately measured by the transit-time technique. Iliac flow increased instantaneously at the beginning of mild exercise (from 12.03 ± 1.06 to 25.55 ± 3.89 ml/min at 15 s) and showed a smaller increase when exercise intensity increased further, reaching a plateau of 38.43 ± 1.92 ml/min at the 4th min of moderate exercise intensity. In contrast, exercise-induced reduction of renal flow was smaller and slower, with 18% and 25% decreases at mild and moderate exercise intensities. Our data indicate that transit-time flowmetry is a reliable method for long-term and continuous measurements of regional blood flow at rest and can be used to quantitate the dynamic flow changes that characterize exercise and recovery

High dietary calcium decreases blood pressure in normotensive rats

This study evaluates the influence of different concentrations of calcium on blood pressure of normotensive rats. Four groups of Wistar rats (A, B, C and D) had free access to modified isocaloric and isoproteic diets containing 0.2, 0.5, 2 and 4 g% calcium as calcium carbonate for a period of 30 days. Systolic and diastolic arterial blood pressures were monitored in awake rats by the indirect tail cuff method using a Physiograph equipped with transducers and preamplifiers. Body weight and length and food intake were monitored. Under the conditions of the present experiment, the systolic and diastolic arterial blood pressures of group D rats fed a diet containing 4 g% calcium were significantly (P<0.05) lower compared to rats of the other groups.

Prosessiautomaatio pinnankorkeusmittauksen koelaitteistoissa

Pinnankorkeuden tunteminen kiehutusvesireaktorin painesäiliössä on erittäin tärkeää sen turvallisuusvaikutusten takia. Pinnankorkeutta mitataan vesipatsaiden korkeutta havaitsevien paine-eromittausten avulla. Säteilyturvakeskuksen YVL-ohjeiden mukaan turvallisuuteen vaikuttavien mittausten täytyy noudattaa moninkertaistus- ja erilaisuusperiaatteita. Yleensä erilaisuusperiaatetta on toteutettu käyttämällä erityyppisiä paine-eromittareita, mutta erilaisella fysikaalisella toimintaperiaatteella oleva mittaus olisi parempi ja toteuttaisi paremmin erilaisuusperiaatetta. Uimurikytkin olisi tällainen fysikaalisesti eri periaatteeseen perustuva pinnankorkeuden mittauslaite. Ydinvoimalaan tarkoitettu teknologia tulee kelpoistaa riippumattoman tahon toimesta ennen käyttöönottoa. Kelpoistamiskokeita varten Lappeenrannan teknillisen yliopiston Ydinturvallisuuden tutkimusyksikköön rakennettiin vuosina 2011–2013 kaksi koelaitteistoa. Näillä koelaitteistoilla tutkittiin uimurikytkimien toimintaa ja ominaisuuksia erilaisissa kiehutusvesireaktorin käyttötilanteissa. Koelaitteistot tarvitsivat toimiakseen automaatiojärjestelmät, jotka suunniteltiin pääosin noudattamalla suunnittelun elinkaarimallia sekä automaatiosuunnittelun sisältökokonaisuuksia. Automaatiojärjestelmien suunnittelu aloitettiin määrittelemällä koejärjestelyjen asettamat vaatimukset, jonka jälkeen tehtiin teknologiavalinnat. Seuraavaksi suunniteltiin automaatiojärjestelmien logiikkaohjelmistot, joiden kuvaukseen tämä työ pääasiassa keskittyy. Logiikkaohjelmistot toteutettiin graafisella National Instruments LabView -ohjelmointikielellä. Logiikkaohjelmistojen tuli hoitaa tiedonkeruuta, käyttöautomaatiota, turvallisuustehtäviä sekä kokeisiin liittyviä erikoistehtäviä. Ohjelmistot saatiin esikokeiden aikana toimimaan halutusti, ja varsinaiset kokeet voitiin suorittaa ilman merkittäviä ongelmia.

A pulsatile flow model for in vitro quantitative evaluation of prosthetic valve regurgitation

A pulsatile pressure-flow model was developed for in vitro quantitative color Doppler flow mapping studies of valvular regurgitation. The flow through the system was generated by a piston which was driven by stepper motors controlled by a computer. The piston was connected to acrylic chambers designed to simulate "ventricular" and "atrial" heart chambers. Inside the "ventricular" chamber, a prosthetic heart valve was placed at the inflow connection with the "atrial" chamber while another prosthetic valve was positioned at the outflow connection with flexible tubes, elastic balloons and a reservoir arranged to mimic the peripheral circulation. The flow model was filled with a 0.25% corn starch/water suspension to improve Doppler imaging. A continuous flow pump transferred the liquid from the peripheral reservoir to another one connected to the "atrial" chamber. The dimensions of the flow model were designed to permit adequate imaging by Doppler echocardiography. Acoustic windows allowed placement of transducers distal and perpendicular to the valves, so that the ultrasound beam could be positioned parallel to the valvular flow. Strain-gauge and electromagnetic transducers were used for measurements of pressure and flow in different segments of the system. The flow model was also designed to fit different sizes and types of prosthetic valves. This pulsatile flow model was able to generate pressure and flow in the physiological human range, with independent adjustment of pulse duration and rate as well as of stroke volume. This model mimics flow profiles observed in patients with regurgitant prosthetic valves.

Arterial blood pressure of term newborns during the first week of life

The progressive behavior of the blood pressure of term newborns during the first week of life was assessed by the simultaneous use of oscillometric and Doppler methods. A total of 174 term neonates born at the Municipal Hospital Odilon Behrens in Belo Horizonte, from March 1996 to February 1997, were prospectively assessed. The oscillometric and Doppler ultrasonic methods were simultaneously used for four consecutive recordings obtained at 12 ± 6, 24 ± 6 and 72 ± 24 h and on the 7th ± 1 day of life. The combined use of the two methods simplified the procedure, with automatic cuff inflation and deflation, and speed was properly controlled with an automatic pressure monitor. The procedure was performed using a Y-connection to the mercury sphygmomanometer, with blood pressure being recorded with an automatic device and systolic blood pressure being measured simultaneously by Doppler ultrasound. The newborns were awake, not crying and in the supine position. A statistically significant increase in systolic and diastolic blood pressure was observed between the first and second, and the third and fourth measurements by Doppler and oscillometric methods. No significant correlation between birth weight, length, ponderal index and blood pressure was observed. The technique used represents a simpler and more accurate procedure for blood pressure measurement.

Effect of topical dorzolamide on rabbit central corneal thickness

Our objective was to study the effect of dorzolamide on corneal hydration in an 18-week controlled experiment using ultrasonic pachymetry. Twenty-eight male rabbits were divided randomly into four groups. The 7 rabbits in each group received eye drops containing either 2% (w/v) dorzolamide or placebo in their right eye, or in their left eye. The 2% dorzolamide rabbits were treated every 8 h. Fellow eyes are defined as eyes which did not receive either dorzolamide or placebo. The study was blind for both the person who applied the drug and the one who performed the pachymetry. The effect of treatments is reported on the basis of the percentage of pachymetric variation compared to the measurement made before drug application. There was no significant difference (P = 0.061) in pachymetric variation between dorzolamide (-4.42 ± 11.71%) and placebo (2.48 ± 9.63%). However, there was a significant difference (P = 0.0034) in pachymetric variation between the dorzolamide fellow eyes (-7.56 ± 10.50%) and the placebo (-4.42 ± 11.71%). In conclusion, dorzolamide did not increase the corneal thickness in rabbits.

Selluloosapohjaisten superkondensaattorien valmistaminen hiilinanoputkista

Tämän työn tarkoitus on seuloa oleelliset prosessiparametrit superkondensaattoreiden elektrodikomposiittien valmistuksessa, jotka vaikuttavat kondensaattorin laatuun. Tarkoitus on tutkia parametreja, joiden avulla prosessia on mahdollista optimoida. Työn tarkoituksena on tutkia myös itse komponenttimateriaalien valmistusvaiheen sekoitusprosessia mitatulla ja laskennallisella seokseen siirtyvällä tehonkulutuksella. Työn kirjallisuusosassa esitetään superkondensaattoreiden rakennetta, toimintamekanismia ja ominaisuuksia sähköenergian varastoijana. Lisäksi tarkastellaan tavallisimpia kondensaattoreihin sisältyviä materiaaleja, erityisesti hiilinanoputkia ja selluloosakuituja. Sekoitusprosesseista tarkastellaan kokeellisessa osassa käytettävien sekoituslaitteita ja niiden toimintamekanismeja komponenttien sekoitusprosesseissa. Kokeellisessa osassa tutkimuskysymyksiksi asetettiin eri sekoitusparametrien (materiaalin määrä ja laatu sekä sekoitusajat) vaikutus superkondensaattorien elektrodiarkkien ominaiskapasitansseihin. Testit suoritettiin LUT Prosessien laboratoriossa, ja testeissä massojen sekoitukseen käytettiin roottoristaattoria ja ultraäänisekoitinta. Lisäksi tutkittiin prosessin skaalausta varten skaalatulla laitteistolla sekoitettuja massanäytteitä. Sekoitusprosessin riittävyyttä varten tutkittiin kokeellisesti käytettyjen sekoituslaitteiden tehonkulutusta. Lisäksi roottoristaattorille tehtiin laskentaohjelmalla virtaussimulaatio paikallisen tehonkulutuksen selvittämiseksi Testeissä todettiin tutkittujen parametrien vaikutus, mutta tulosten perusteella varsinaista optimointia ei kyetty tekemään. Tulokset kuitenkin antavat suunnan, johon prosessia voi optimointia varten kehittää. Myös sekoitukseen todettiin siirtyvän suuri määrä tehoa tutkituilla laitteilla, mitä voidaan pitää mahdollisesti riittävänä käytettyjen komponenttien sekoitukseen.

Comparison of the effects of lactated Ringer solution with and without hydroxyethyl starch fluid resuscitation on gut edema during severe splanchnic ischemia

The type of fluid used during resuscitation may have an important impact on tissue edema. We evaluated the impact of two different regimens of fluid resuscitation on hemodynamics and on lung and intestinal edema during splanchnic hypoperfusion in rabbits. The study included 16 female New Zealand rabbits (2.9 to 3.3 kg body weight, aged 8 to 12 months) with splanchnic ischemia induced by ligation of the superior mesenteric artery. The animals were randomized into two experimental groups: group I (N = 9) received 12 mL·kg-1·h-1 lactated Ringer solution and 20 mL/kg 6% hydroxyethyl starch solution; group II (N = 7) received 36 mL·kg-1·h-1 lactated Ringer solution and 20 mL/kg 0.9% saline. A segment from the ileum was isolated to be perfused. A tonometric catheter was placed in a second gut segment. Superior mesenteric artery (Q SMA) and aortic (Qaorta) flows were measured using ultrasonic flow probes. After 4 h of fluid resuscitation, tissue specimens were immediately removed for estimations of gut and lung edema. There were no differences in global and regional perfusion variables, lung wet-to-dry weight ratios and oxygenation indices between groups. Gut wet-to-dry weight ratio was significantly lower in the crystalloid/colloid-treated group (4.9 ± 1.5) than in the crystalloid-treated group (7.3 ± 2.4) (P < 0.05). In this model of intestinal ischemia, fluid resuscitation with crystalloids caused more gut edema than a combination of crystalloids and colloids.

Involvement of midbrain tectum neurokinin-mediated mechanisms in fear and anxiety

Electrical stimulation of midbrain tectum structures, particularly the dorsal periaqueductal gray (dPAG) and inferior colliculus (IC), produces defensive responses, such as freezing and escape behavior. Freezing also ensues after termination of dPAG stimulation (post-stimulation freezing). These defensive reaction responses are critically mediated by γ-aminobutyric acid and 5-hydroxytryptamine mechanisms in the midbrain tectum. Neurokinins (NKs) also play a role in the mediation of dPAG stimulation-evoked fear, but how NK receptors are involved in the global processing and expression of fear at the level of the midbrain tectum is yet unclear. The present study investigated the role of NK-1 receptors in unconditioned defensive behavior induced by electrical stimulation of the dPAG and IC of male Wistar rats. Spantide (100 pmol/0.2 μL), a selective NK-1 antagonist, injected into these midbrain structures had anti-aversive effects on defensive responses and distress ultrasonic vocalizations induced by stimulation of the dPAG but not of the IC. Moreover, intra-dPAG injections of spantide did not influence post-stimulation freezing or alter exploratory behavior in rats subjected to the elevated plus maze. These results suggest that NK-1 receptors are mainly involved in the mediation of defensive behavior organized in the dPAG. Dorsal periaqueductal gray-evoked post-stimulation freezing was not affected by intra-dPAG injections of spantide, suggesting that NK-1-mediated mechanisms are only involved in the output mechanisms of defensive behavior and not involved in the processing of ascending aversive information from the dPAG.

Intercostal and forearm muscle deoxygenation during respiratory fatigue in patients with heart failure: potential role of a respiratory muscle metaboreflex

The purpose of this study was to determine the effect of respiratory muscle fatigue on intercostal and forearm muscle perfusion and oxygenation in patients with heart failure. Five clinically stable heart failure patients with respiratory muscle weakness (age, 66±12 years; left ventricle ejection fraction, 34±3%) and nine matched healthy controls underwent a respiratory muscle fatigue protocol, breathing against a fixed resistance at 60% of their maximal inspiratory pressure for as long as they could sustain the predetermined inspiratory pressure. Intercostal and forearm muscle blood volume and oxygenation were continuously monitored by near-infrared spectroscopy with transducers placed on the seventh left intercostal space and the left forearm. Data were compared by two-way ANOVA and Bonferroni correction. Respiratory fatigue occurred at 5.1±1.3 min in heart failure patients and at 9.3±1.4 min in controls (P<0.05), but perceived effort, changes in heart rate, and in systolic blood pressure were similar between groups (P>0.05). Respiratory fatigue in heart failure reduced intercostal and forearm muscle blood volume (P<0.05) along with decreased tissue oxygenation both in intercostal (heart failure, -2.6±1.6%; controls, +1.6±0.5%; P<0.05) and in forearm muscles (heart failure, -4.5±0.5%; controls, +0.5±0.8%; P<0.05). These results suggest that respiratory fatigue in patients with heart failure causes an oxygen demand/delivery mismatch in respiratory muscles, probably leading to a reflex reduction in peripheral limb muscle perfusion, featuring a respiratory metaboreflex.

Development of a rapid method for the determination of antibiotic residues in honey using UPLC-ESI-MS/MS

Abstract An accurate, reliable and fast multianalyte/multiclass ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was developed and validated for the simultaneous analysis of 23 pharmaceuticals, belonging to different classes amphenicols, sulfonamides, tetracyclines, in honey samples. The method developed consists of ultrasonic extraction followed by UPLC–ESI–MS/MS with electrospray ionization in both positive mode and negative mode. The influence of the extraction solvents and mobile phase composition on the sensitivity of the method, and the optimum conditions for sample weight and extraction temperature in terms of analyte recovery were extensively studied. The identification of antibiotics is fulfilled by simultaneous use of chromatographic separation using an Acquity BEH C18 (100 mm x 2.1 mm, 1.7 µm) analytical column with a gradient elution of mobile phases and tandem mass spectrometry with an electrospray ionization. Finally, the method developed was applied to the determination of target analytes in honey samples obtained from the local markets and several beekeepers in Muğla, Turkey. Ultrasonic-extraction of pharmaceuticals from honey samples is a well-established technique by UPLC–ESI–MS/MS, the uniqueness of this study lies in the simultaneous determination of a remarkable number of compounds belonging to 23 drug at the sub-nanogram per kilogram level.

On site measurements of DC link electrolytic capacitor bank of frequency converter using constant DC magnetization of the motor

Preventive maintenance of frequency converters has been based on pre-planned replace-ment of wearing or ageing components. Exchange intervals follow component life-time expectations which are based on empirical knowledge or schedules defined by manufac-turer. However, the lifetime of a component can vary significantly, because drives are used in very different operating environments and applications. The main objective of the research was to provide information on methods, i.e. how in-verter's operating condition can be measured reliably under field conditions. At first, the research focused on critical components such as current transducers, IGBTs and DC link capacitor bank, because these aging have already been identified. Of these, the DC link capacitor measurement method was selected for closer examination. With this method, the total capacitance and its total series resistance can be measured. The suitability of the measuring procedure was estimated on the basis of practical measurements. The research was made by using so called triangulation method, including a literature review, simulations and practical measurements. Based on the results, the new measu-rement method seems suitable with some reservations to practical measurements. How-ever, the measuring method should be further developed in order to improve its reliability.