CLEANING AND PREVENTION OF INORGANIC DEPOSITS IN PLATE HEAT EXCHANGERS USING PULSATING CURRENT

Fouling of heat exchangers is a major problem in many industrial processes. The higher temperature of the heat exchange surface compared with the liquid containing precipitable compounds causes the formation of inorganic deposits. Removing the deposits on plate heat exchangers is most often carried out by high-pressure cleaning. This is a laborious task and often increases the corrosion rate of the plates by increasing the roughness of the cleaned surface. This study presents an electrochemical method to clean heat exchange surfaces fouled by deposits and to prevent formation of deposits. This method utilizes pulsating current to polarize heat exchange surfaces with periodic anodic and cathodic DC current. The shape of the pulse and the current density are adjusted to maximize the deposit removal rate, thus minimizing plate corrosion. The optimal pulsating current depends on the material of the heat exchange surface, as well as the composition of the deposits and the solution. For cleaning, the current densities and the frequency of the current pulse are typically higher than those used for preventing deposition. Pulsating current can effectively remove deposits with low solubility, such as TiO2 on titanium heat exchange plates or dense gypsum deposits on stainless steel plates. For cleaning titanium, the cathodic pulse and formation of hydrogen is more essential than in the cleaning of stainless steels. However, the risk of corrosion limits the use of high current densities. Experiments have until now been carried out mainly in the laboratory, though industrial pilot cleaning equipment has also been constructed. An application has already been submitted to patent the method

Laskentaesimerkkejä betonisiltojen vahventamiseksi

Tiivistelmä. Diplomityössä mitoitetaan kolmeaukkoisen teräsbetonisen laattasillan päällysrakenteen vahventaminen poikkileikkausta kasvattamalla uuden Betonisiltojen korjaus- ja vahventamissuunnitteluohjeen luonnosversion (12/2021) mukaisesti. Työtä tehdessä tutkitaan uuden vahventamisohjeen luonnosversion soveltuvuutta todellisen sillan vahvennoksen mitoitukseen. Työssä mitoitetaan myös yksiaukkoisen teräsbetonisen palkkisillan pääkannatinpalkkien vahventaminen liimausvahventamalla uuden Betonisiltojen korjaus- ja vahventamissuunnitteluohjeen luonnosversion (12/2021) mukaisesti. Liimausvahventamisohjeen luonnosversio kattaa ohjeistuksen murtorajatilan tarkasteluihin niin kutsutulla yksinkertaistetulla liimausvahventamisen mitoitusmenetelmällä. Laskelmissa tutkitaan yksinkertaistetun laskentamenetelmän soveltuvuutta todellisen sillan vahventamiseen. Laskentojen tarkoituksena on edesauttaa uuden liimausvahventamisen ohjetekstin laadintaa. Työssä todettiin, että luonnosversiossa (12/2021) esitetty ohje vahventaminen poikkileikkausta kasvattamalla ei sovellu vielä ohjeen keskeneräisyyden vuoksi todellisen sillan vahvennoksen mitoitukseen. Työssä todettiin myös, että yksinkertaistetulla liimausvahventamisen laskentamenetelmällä saadaan kasvatettua rakenteen taivutuskapasiteettia hyvin maltillisesti, sillä menetelmä määrittää todella konservatiivisia rajoituksia vahvikkeen vetojännitykselle tartuntamurron estämiseksi.Calculation examples for concrete bridge strengthening. Abstract. This master’s thesis considers strengthening of a three-span reinforced concrete slab bridge in accordance with the draft version of the new Concrete bridge repair and strengthening design guide (12/2021). This thesis also describes the design of strengthened beams with the adhesively bonded reinforcement of a single-span reinforced concrete beam bridge. It was found that the instructions in the draft version of the strengthening guide are still incomplete for dimensioning. It was also found that simplified bonding reinforcement calculation method provides a very small increase in the bending capacity of the structure, since the method determines the truly conservative limitations of the reinforcement tensile stress to prevent infectious breach

Does better education mitigate risky health behavior? A mendelian randomization study

Education and risky health behaviors are strongly negatively correlated. Education may affect health behaviors by enabling healthier choices through higher disposable income, increasing information about the harmful effects of risky health behaviors, or altering time preferences. Alternatively, the observed negative correlation may stem from reverse causality or unobserved confounders. Based on the data from the Cardiovascular Risk in Young Finns Study linked to register-based information on educational attainment and family background, this paper identifies the causal effect of education on risky health behaviors. To examine causal effects, we used a genetic score as an instrument for years of education. We found that individuals with higher education allocated more attention to healthy habits. In terms of health behaviors, highly educated people were less likely to smoke. Some model specifications also indicated that the highly educated consumed more fruit and vegetables, but the results were imprecise in this regard. No causal effect was found between education and abusive drinking. In brief, inferences based on genetic instruments showed that higher education leads to better choices in some but not all dimensions of health behaviors

Archaea are prominent members of the prokaryotic communities colonizing common forest mushrooms

In this study, the abundance and composition of prokaryotic communities associated with the inner tissue of fruiting bodies of Suillus bovinus, Boletus pinophilus, Cantharellus cibarius, Agaricus arvensis, Lycoperdon perlatum, and Piptoporus betulinus were analyzed using culture-independent methods. Our findings indicate that archaea and bacteria colonize the internal tissues of all investigated specimens and that archaea are prominent members of the prokaryotic community. The ratio of archaeal 16S rRNA gene copy numbers to those of bacteria was >1 in the fruiting bodies of four out of six fungal species included in the study. The largest proportion of archaeal 16S rRNA gene sequences belonged to thaumarchaeotal classes Terrestrial group, Miscellaneous Crenar-chaeotic Group (MCG), and Thermoplasmata. Bacterial communities showed characteristic compositions in each fungal species. Bacterial classes Gammaproteobacteria, Actinobacteria, Bacilli, and Clostridia were prominent among communities in fruiting body tissues. Bacterial populations in each fungal species had different characteristics. The results of this study imply that fruiting body tissues are an important habitat for abundant and diverse populations of archaea and bacteria.Peer reviewe

The serum copper/zinc ratio in childhood and educational attainment: a population-based study

BACKGROUND: Micronutrients are potentially important determinants of adult outcomes such as educational attainment. Copper and zinc have known effects on several medical conditions and cognitive development. Elevated copper and depressed zinc is a common trace metal imbalance. METHODS: We estimate the correlation between the copper/zinc ratio (Cu/Zn) in childhood (year 1980) and educational attainment in adulthood (year 2010). We use the Young Finns Study (YFS) combined with the Finnish Linked Employer-Employee Data (FLEED). The regression models account for confounders such as other biomarkers and parental observables. RESULTS: We report a sizeable, negative correlation between Cu/Zn and educational attainment as measured by education in years, grades as well as the likelihood of completing university education. For example, a one standard deviation increase in Cu/Zn decreases the probability of university education by ∼4%. CONCLUSIONS: The findings are consistent with a Cu/Zn effect influencing cognitive functioning early in life. Future research should explore more deeply the precise mechanisms by which Cu/Zn affects educational attainment

Creatine and entrepreneurship

Creatine is a nitrogenous organic acid which supplies energy to body cells and enhances physical performance. Using the Young Finns Study combined with the Finnish Linked employer-employee data we show that quantities of creatine measured in 1980 prior to labour market entry affect entrepreneurial success as measured by capital income accumulation over the period 1993–2010 (in particular for females). However, we do not find evidence that creatine affects the propensity to become an entrepreneur. Our study contributes to the emerging literature on biomarkers and entrepreneurship

Työolosuhteiden mukauttaminen vammaisilla henkilöillä: vaikuttavuus sekä estävät ja edistävät tekijät. Järjestelmällinen kirjallisuuskatsaus

Katsauksen tavoitteena oli selvittää työolosuhteiden mukauttamisen vaikuttavuutta vammaisten henkilöiden työelämään osallistumiseen, työkykyyn ja mukautustoimenpiteiden kustannushyötyyn. Toisena tavoitteena oli kuvata työolosuhteiden mukauttamista estäviä ja edistäviä tekijöitä. Katsausta varten haettiin työolosuhteiden mukauttamista koskevia määrällisiä ja laadullisia tutkimuksia. Tulosmuuttujina oli työelämässä oleminen (työllistyminen, työssä jatkaminen, työhön paluu), työkyky ja kustannushyöty. Laadullisissa tutkimuksissa selvitettiin työolosuhteiden mukauttamista estäviä ja edistäviä tekijöitä. Tutkimusten kohderyhmänä oli työikäiset (16−68 v) henkilöt, joilla oli liikunta-, näkö- tai kuulovamma, kognitiivinen häiriö tai kehitysvamma. Englanninkieliset vertaisarvioidut alkuperäisartikkelit piti olla julkaistu välillä tammikuu 1990–marraskuu 2012. Haku tehtiin 10 tietokannasta: Embase, CINAHL, Cochrane Library, Medic, OTseeker, PEDro, PsycInfo, PubMed, Scopus ja Web of Science. Katsaukseen otettiin mukaan kolme määrällistä ja kahdeksan laadullista tutkimusta. Tulosten perusteella on kohtalaista näyttöä siitä, että kohdennettu työolosuhteiden mukauttaminen (ammatillinen neuvonta ja ohjaus, koulutus ja pystyvyyden vahvistaminen, toisten antama apu, työaikajärjestelyt ja työn organisointi) tukee liikuntavammaisten henkilöiden työssä olemista ja vähentää kustannuksia. Vähäinen näyttö on siitä, että ”case-managerien” koordinoima työolosuhteiden mukauttaminen (yhteistyö, koulutus, apuvälineet, työmenetelmät) aivovamman jälkeen lisäisi työhön paluuta ja olisi perinteistä hoitoa kustannustehokkaampaa. Työssä olemista edistivät henkilön hyvä pystyvyyden tunne, työnantajan ja työyhteisön tuki, opastus ja ohjaus, sekä joustavat työaikajärjestelyt ja työn organisointi. Tarvitaan enemmän korkealaatuisia tutkimuksia, joissa vammaisten työ- ja toimintakykyä mitataan validoiduilla menetelmillä ja tutkimusasetelmissa hyödynnetään laadullisten tutkimusten tuloksia

Health endowment and later-life outcomes in the labour market: Evidence using genetic risk scores and reduced-form models

This paper examines the relationship between health endowment and later-life outcomes in the labour market. The analysis is based on reduced-form models in which labour market outcomes are regressed on genetic variants related to the increased risk of cardiovascular diseases. We use linked Finnish data that have many strengths. Genetic risk scores constitute exogenous measures for health endowment, and accurate administrative tax records on earnings, employment and social income transfers provide a comprehensive account of an individual’s long-term performance in the labour market. The results show that although the direction of an effect is generally consistent with theoretical reasoning, the effects of health endowment on outcomes are statistically weak, and the hypothesis of no effect can be rejected only in one case: genetic endowment related to obesity influences male earnings and employment in prime age. Due to the sample size (N = 1651), the results should be interpreted with caution and should be confirmed in larger samples and in other institutional settings.</p