The optimization of the scale growth model for line annealing in stainless steel production

Abstract. The aim of this thesis was to optimize an industrial scale growth model for stainless steel annealing. The focus of the experimental work conducted for this thesis was on the effect of annealing temperature and atmosphere within the annealing furnace on the amount of scale formed during annealing. In addition, the effect of annealing time was studied through the means of microscopy. The results of the experimental work were fitted into mathematical models discovered during the literature review. Thanks to this, the amount of scale formed during annealing can now be predicted thermodynamically. A literature review was performed for this thesis on industrial scale final annealing, the fuels used in industrial scale processes and their effects on e.g., the scale growth during the process and existing mathematical modelling methods and appliances. The experimental work consisted of simulating the annealing of cold rolled AISI 304, AISI 309 and AISI 441 on an industrial scale annealing- and pickling line. The purpose of the experiment was to simulate the scale growth taking place on an industrial scale annealing furnace and gather information on the effect of annealing temperature and atmosphere within the furnace on the amount of scale formed. Studied annealing temperatures ranged between 950–1250 °C and the holding time was 15 minutes. Three different atmospheres were used, simulating the usage of liquid natural gas burned with both air and oxygen enriched air as well as hydrogen burned with oxygen enriched air. In addition, stoppage experiments were conducted on AISI 304 with annealing times of one, five, ten and 15 minutes to study the effect of annealing time on scale growth. The experiments were conducted in a vertical tube furnace, with a weighing scale fixed above the furnace hanging and measuring the mass of the samples. The equipment used for microscopy was a FESEM-EDS. In most cases it was noted, that a higher temperature would cause a higher amount of oxidation. None of the simulated atmospheres were found to cause explicitly more oxidation than the other two between the studied atmospheres, and differences varied from temperature to temperature. A longer annealing time was observed to cause more oxidation, as was expected. When comparing the simulated liquid natural gas burned with air to hydrogen burned with oxygen enriched air as a fuel, no major difference was found in the morphology or depth of the scale formed. The results from experimental work were fitted into functional models. Using the Arrhenius-equation, activation energies and frequency factors could be calculated. These results permit the thermodynamic prediction of the amount of scale formed, and their implementation to an industrial scale.Nauhahehkutuksen hilseenkasvumallin optimointi ruostumattomien terästen valmistuksessa. Tiivistelmä. Tämän työn tavoitteena oli optimoida teollisessa mittakaavassa käytössä oleva ruostumattoman teräksen loppuhehkutuksen hilseenkasvumalli. Työtä varten tehdyn tutkimuksen pääpainoina olivat hehkutuslämpötilan ja hehkutusuunissa vallitsevan atmosfäärin vaikutus hilseenkasvun määrään, jonka lisäksi hehkutusajan vaikutusta hilseenkasvuun tutkittiin mikroskopoimalla. Kokeellisen työn tulokset sovitettiin kirjallisuusselvityksessä löydettyihin malleihin, joiden ansiosta hilseenkasvua pystytään ennustamaan termodynaamisesti. Työtä varten suoritettiin kirjallisuuskatsaus liittyen teollisen mittakaavan loppuhehkutukseen, teollisissa prosesseissa käytettäviin polttoaineisiin sekä niiden vaikutuksista mm. hilseenkasvuun sekä olemassa oleviin matemaattisiin mallinnuskeinoihin ja niiden hyödyntämiseen. Kokeellisessa osuudessa simuloitiin kylmävalssattujen AISI 304, AISI 309 sekä AISI 441 loppuhehkutusta hehkutus- ja peittauslinjalla. Kokeiden tarkoituksen oli simuloida hilseenkasvua tuotantolinjalla ja saada tietoa hehkutusolosuhteiden vaikututuksista muodostuvan hilseen määrään. Hehkutusolosuhteina käytettiin 950–1250 °C lämpötiloja, 15 minuutin pitoaikoja sekä kolmea eri atmosfääriä, jotka simuloivat maakaasun polttoa ilmalla ja happirikastetulla ilmalla sekä vedyn polttoa happirikastetulla ilmalla. Lisäksi AISI 304 ruostumattomalle teräkselle tehtiin pysäytyskokeita, joiden pitoajat olivat yksi, viisi, kymmenen ja 15 minuuttia hehkutusajan vaikutuksen tutkimiseksi. Kokeet suoritettiin pystysuorassa putkimaisessa hehkutusuunissa, ja näytteiden massaa mitattiin jatkuvasti uunin yläpuolelle kiinnitetyn vaa’an avulla. Mikroskopoinnissa käytettiin FESEM-EDS-laitteistoa. Suurimassa osassa tapauksia korkeamman lämpötilan havaittiin aiheuttavan enemmän hapettumista. Yksikään simuloiduista atmosfääreistä ei noussut selkeästi kaikista eniten hapettumista aiheuttavaksi, vaan tilanne vaihteli tapauskohtaisesti. Pidemmän hehkutusajan havaittiin aiheuttavan enemmän hapettumista. Verrattaessa ilmalla poltettua maakaasua ja happirikastetulla ilmalla poltettua vetyä hehkutuksen polttoaineena, ei havaittu merkittävää eroa hilsekerrosten koostumuksen tai syvyyden suhteen. Kokeellisesta työstä saadut tulokset sovitettiin toimiviksi havaittuihin malleihin, jonka tuloksena saatiin laskettua aktivaatioenergiat ja taajuustekijät Arrhenius-yhtälön avulla. Näiden tuloste ansiosta hehkutuksessa syntyvän hilseen määrä pystytään ennustamaan termodynaamisesti, ja tuloksia voidaan sovittaa teolliseen mittakaavaan

Severe Anaphylaxis to Volplex, a Colloid Solution during Cesarean Section: A Case Report and Review

Anaphylaxis is a life-threatening event that can occur anytime during pregnancy. It has been reported following administration of various substances with adverse maternal and neonatal consequences. It should be considered in the differential diagnosis of intrapartum collapse. We encountered a case of severe anaphylactic reaction following a routine cesarean section. It is very important that all members of the perinatal team are aware of early recognition and management of anaphylactic reaction. We think that it is important to highlight this as a further case report of severe anaphylactic reaction to a colloid solution and discuss the pathophysiology and management

Statistical Processing of Subjective Test Data for Sound Quality Evaluation of Automotive Horn

Product sound quality has a significant role in buying decision and customer satisfaction. An often used method to assess the sound quality of any product or equipment is a subjective listening test where the sound is heard by a panel of subjects (jury) who then rate the sound quality. Subjects use a semantic differential rating wherein they evaluate the presented sounds based on a bipolar variable. The two extremes of the rating scale are labeled with an adjective and its antonym respectively. In the present study, a subjective listening test has been conducted to assess sound quality of automotive horns. The data obtained are then analyzed using statistics to gain insights. Twenty two horn sound samples were judged by thirty participants aged 20-40 years who had normal hearing. Binaural head set (BHS) instrument was used to record horn sound samples in open ground (neglecting wind noise effect). Sounds are recorded two meter from horn in front direction and used for subjective test. For the subjective test and subsequent statistical analysis, a four step procedure has been used. In the first step, the participants were asked to rate the sound quality for each horn based on seven bipolar variables. These bipolar variables are soft/loud, calm/frightening, slow/fast, relax/tense, safe/danger, vague/distinct and pleasant/unpleasant. For each bipolar variable, a seven verbal interval scale was used ranging from one extreme to another in degree, for example extremely pleasant to extremely unpleasant

”Entä jos ei pysy pinnalla?”:tutkimus 6–12-vuotiaiden lisäuimaopetuksen järjestämisestä Oulun kaupungissa

Tiivistelmä. Tutkielman tarkoituksena on kuvata Oulun koulu-uimaopetuksen lisäopetusjärjestelmää ja sen toteuttamistapaa. Oulun kaupunki järjestää kaikille esikoululaisille sekä 1.–6. luokkalaisille maksutonta uimaopetusta. Jokainen luokka käy uimaopetuksessa yhden viikon jokaisena lukuvuotena. Tämän lisäksi heikkouimataitoisille sekä uimataidottomille järjestetään lisäuimaopetusta kesällä. Tutkimuksen tavoitteena on kuvata lisäuimaopetuksen järjestämismallia, tuoda esille sen vaikutuksia uimataitoon sekä perehtyä sen järjestämiseen liittyviin haasteisiin ja kehitysmahdollisuuksiin. Tutkimuksen teema oli Oulun koulu-uimaopetusjärjestelmän toimivuus. Tutkimuksen teoreettinen lähtökohta on uimaopetuksen tärkeys sekä sen esiintyminen perusopetuksen opetussuunnitelman perusteissa. Tutkielman teoria perustuu monipuolisesti suomalaiseen uimaopetukseen ja sen näkyvyyteen suomalaisen perusopetuksen opetussuunnitelmassa. Uimataidon opettamisen maininta opetussuunnitelmassa edellyttää kouluja, kaupunkeja ja kuntia tarjoamaan oppilaille uimaopetusta jokaisella luokka-asteella. Tapaustutkimuksen aineisto kerättiin haastattelemalla kahta esimiestä, yhtä vakituista uimaopettajaa ja kolmea kesäuimaopettajaa. Tutkimusaineisto koostui neljästä yksilöhaastattelusta sekä yhdestä parihaastattelusta. Aineisto analysoitiin aineistolähtöisellä sisällön analyysillä. Tutkimuksen tulokset osoittavat, että lisäuimaopetusta järjestetään pääsääntöisesti kesäisin. Lisäuimaopetuksella on havaittu olevan positiivisia vaikutuksia uimataitoon, mutta sen järjestämiseen liittyy myös monia haasteita. Lisäuimaopetuksen kehittämiseen nousi esiin monia kehittämismahdollisuuksia, joiden toteuttaminen vaatisi uudelleen resursointia sekä rakennemuutoksia. Esimerkiksi uusi uimahalli, seurayhteistyö ja lisäuimaopetuksen ajoituksen tarkoituksenmukaistaminen tehostaisivat lisäuimaopetusta Oulussa

Fibonaccin luvut

Tiivistelmä. Tässä tutkielmassa tutustutaan Fibonaccin lukuihin. Tarkoituksena on antaa rekursiivinen määritelmä Fibonaccin luvuille sekä tutkia niitä lukuteorian näkökulmasta. Lisäksi tutkitaan Fibonaccin lukujen yhteyttä kultaiseen leikkaukseen ja Binet’n kaavaan. Tutkielman lopuksi todistetaan Zeckendorfin lause

Palveleva johtaminen etätyössä

Tiivistelmä. Tämän kandidaatintutkielman tarkoituksena on perehtyä palvelevan johtamisen vaikutuksiin etätyössä. Tutkimus käsittelee palvelevaa johtamista sekä etätyön johtamista yksittäisinä käsitteinä, sekä tutkii kuinka ne ovat suhteessa toisiinsa. Tutkielman tavoitteena on selvittää onko palveleva johtaminen etätyön johtamiseen soveltuva johtamistyyli

Rapid prototyping modelling in oral and maxillofacial surgery: a two year retrospective study

Background: The use of rapid prototyping (RP) models in medicine to construct bony models is increasing. Material and Methods: The aim of the study was to evaluate retrospectively the indication for the use of RP models in oral and maxillofacial surgery at Helsinki University Central Hospital during 2009-2010. Also, the used computed tomography (CT) examination – multislice CT (MSCT) or cone beam CT (CBCT) - method was evaluated. Results: In total 114 RP models were fabricated for 102 patients. The mean age of the patients at the time of the production of the model was 50.4 years. The indications for the modelling included malignant lesions (29%), secondary reconstruction (25%), prosthodontic treatment (22%), orthognathic surgery or asymmetry (13%), benign lesions (8%), and TMJ disorders (4%). MSCT examination was used in 92 and CBCT examination in 22 cases. Most of the models (75%) were conventional hard tissue models. Models with colored tumour or other structure(s) of interest were ordered in 24%. Two out of the 114 models were soft tissue models. Conclusions: The main benefit of the models was in treatment planning and in connection with the production of pre-bent plates or custom made implants. The RP models both facilitate and improve treatment planning and intraoperative efficiency

Biomarkers of Pediatric Brain Tumors

Background and Need for Novel Biomarkers: Brain tumors are the leading cause of death by solid tumors in children. Although improvements have been made in their radiological detection and treatment, our capacity to promptly diagnose pediatric brain tumors in their early stages remains limited. This contrasts several other cancers where serum biomarkers such as cancer antigen (CA) 19-9 and CA 125 facilitate early diagnosis and treatment. Aim: The aim of this article is to review the latest literature and highlight biomarkers which may be of clinical use in the common types of primary pediatric brain tumor. Methods: A PubMed search was performed to identify studies reporting biomarkers in the bodily fluids of pediatric patients with brain tumors. Details regarding the sample type [serum, cerebrospinal fluid (CSF), or urine], biomarkers analyzed, methodology, tumor type, and statistical significance were recorded. Results: A total of 12 manuscripts reporting 19 biomarkers in 367 patients vs. 397 controls were identified in the literature. Of the 19 biomarkers identified, 12 were isolated from CSF, 2 from serum, 3 from urine, and 2 from multiple bodily fluids. All but one study reported statistically significant differences in biomarker expression between patient and control groups. Conclusion: This review identifies a panel of novel biomarkers for pediatric brain tumors. It provides a platform for the further studies necessary to validate these biomarkers and, in addition, highlights several techniques through which new biomarkers can be discovered

Adaptive evolution after duplication of penaeidin antimicrobial peptides

Penaeidin antimicrobial peptides in penaeid shrimps are an important component of their innate immune system that provides immunity against infection caused by several gram-positive bacteria and filamentous fungal species. Despite the knowledge on the identification and characterization of these peptides in penaeid shrimps, little is known about the evolutionary pattern of these peptides and the underlying genetic mechanisms that maintain high sequence diversities in the penaeidin gene family. Based on the phylogenetic analyses and maximum likelihood-based codon substitution analyses, here we present the convincing evidence that multiple copies of penaeidins have evolved by gene duplication, and positive Darwinian selection (adaptive evolution) is the likely cause of accelerated rate of amino acid substitutions among these duplicated genes.fisheries of the country has led to a remarkable increase in fish landings, the problem of by-catch and targeted juvenile fishing is ever increasing. The present analysis shows that the contribution in the form of annual average profit by various craft–gear combinations is often not sufficient to compensate the overall loss generated by the same to the fishery through the harvest of juvenile fishes. Even though the fishermen gain some transient economic incentives from the juveniles landed, the estimated economic loss calculated was at about US$ 19,445 million year−1 from the mechanised as well as motorised sector. Both intergenerational and conventional discounting was applied to show the net present value (NPV) of future loss due to juvenile fishing. Some of the less capital intensive gears also substantially contribute towards the economic deficit caused by juvenile fishing. We suggest that, while considering the ecosystem impacts of accidental by-catch and intentional juvenile fishing, the economic impacts also should be taken into account prior to formulating any management measures. The study provides an insight to the cost of juvenile fishing in a multi-species multi-gear fishery, where a homogeneous management system is ineffective. The possible causes of increased growth overfishing in the country and subsequent economic loss to the industry are also discussed

Fish hook in classifier efficiency curves: An update

Fish hook in classifier efficiency curves has been receiving attention in the last three decades, more so with the advent of laser diffractometry. In the first part of this paper, we analyse two occurrences of fish hook reported recently in Separation and Purification Technology. It is shown that in both the cases, inaccuracies in measured particle size distributions could be the likely cause of the observed fish hook. In the second part, we re-examine the present state of knowledge on fish hook including the limitations of experimental observations reported so far and the drawbacks of theoretical explanations. Finally, we provide a basis on why it is to be considered nothing more than a scientifically insignificant placebo