Utilization of cold spraying in additive manufacturing

Kylmäruiskutus on suhteellisen uusi pinnoitteiden valmistusmenetelmä, jota on viime vuosina alettu hyödyntämään ainetta lisäävässä valmistuksessa. Perinteisistä ainetta lisäävistä valmistusmenetelmistä poiketen kylmäruiskutus perustuu termisten energioiden hyödyntämisen sijasta matalissa lämpötiloissa hyödynnettäviin suuriin kineettisiin energioihin. Matalista lämpötiloista johtuen kylmäruiskutuksella saavutetaan muista menetelmistä poikkeavia ominaisuuksia rakenteelle, mistä johtuen menetelmä on herättänyt kiinnostusta ja on ollut jatkuvan kehityksen kohteena keksimisestään lähtien. Tämä kandidaatintyö käsittelee kylmäruiskutustekniikoiden hyödynnettävyyttä ja mahdollisuuksia ainetta lisäävässä valmistuksessa. Työn alussa esitellään yleisesti kylmäruiskutuksen teoreettista taustaa käyden läpi erilaisten menetelmien periaatteita, ominaisuuksia ja etuja, joita myöhemmin verrataan yleisempiin ainetta lisääviin valmistusmenetelmiin. Tämän jälkeen esitellään työn yhteydessä suoritettavan kokeellisen osuuden suorittaminen ja näin saadut tulokset, joita tarkastellaan ja verrataan tunnettuun teoriaan työn loppupuolella. Lopputuloksena tutkimukselle määritettiin kirjallisuuden lähteiden vertailun perusteella kylmäruiskutuksen mahdollisuudet ainetta lisäävässä valmistuksessa ja tutkittiin pinnoitteiden ominaisuuksia analysoimalla itse suoritettujen kokeiden tuloksia. Todettiin myös kylmäruiskutuksen kehityksen ainetta lisäävänä menetelmänä olevan vielä keskeneräistä, mutta jatkuvan kehityksen alla

Utilization of cold spraying in additive manufacturing

Kylmäruiskutus on suhteellisen uusi pinnoitteiden valmistusmenetelmä, jota on viime vuosina alettu hyödyntämään ainetta lisäävässä valmistuksessa. Perinteisistä ainetta lisäävistä valmistusmenetelmistä poiketen kylmäruiskutus perustuu termisten energioiden hyödyntämisen sijasta matalissa lämpötiloissa hyödynnettäviin suuriin kineettisiin energioihin. Matalista lämpötiloista johtuen kylmäruiskutuksella saavutetaan muista menetelmistä poikkeavia ominaisuuksia rakenteelle, mistä johtuen menetelmä on herättänyt kiinnostusta ja on ollut jatkuvan kehityksen kohteena keksimisestään lähtien. Tämä kandidaatintyö käsittelee kylmäruiskutustekniikoiden hyödynnettävyyttä ja mahdollisuuksia ainetta lisäävässä valmistuksessa. Työn alussa esitellään yleisesti kylmäruiskutuksen teoreettista taustaa käyden läpi erilaisten menetelmien periaatteita, ominaisuuksia ja etuja, joita myöhemmin verrataan yleisempiin ainetta lisääviin valmistusmenetelmiin. Tämän jälkeen esitellään työn yhteydessä suoritettavan kokeellisen osuuden suorittaminen ja näin saadut tulokset, joita tarkastellaan ja verrataan tunnettuun teoriaan työn loppupuolella. Lopputuloksena tutkimukselle määritettiin kirjallisuuden lähteiden vertailun perusteella kylmäruiskutuksen mahdollisuudet ainetta lisäävässä valmistuksessa ja tutkittiin pinnoitteiden ominaisuuksia analysoimalla itse suoritettujen kokeiden tuloksia. Todettiin myös kylmäruiskutuksen kehityksen ainetta lisäävänä menetelmänä olevan vielä keskeneräistä, mutta jatkuvan kehityksen alla

Soil vapor extraction of wet gasoline-contaminated soil made possible by electroosmotic dewatering-lab simulations applied at a field site

PurposeSoil restoration is still mainly carried out ex situ by excavating and replacing the contaminated soil. In situ remediation would reduce the costs of soil transportation and this way, the problem is not merely transferred elsewhere. The present study introduces a field case where the aged, oil-contaminated soil in a former fuel station in Finland was treated in situ sequentially with different methods.Materials and methodsSeveral approaches, including soil vapor extraction and biostimulation with electrokinetic pumping, were performed in the field. After these treatments, the dense original portion of the soil beneath the gasoline pump location, ca 100m(3), was still contaminated with petroleum-derived volatile organic compounds (VOCs), with concentrations of nearly 10,000mgkg(-1) measured at some hotspots. After a period of electroosmotic water circulation, the electrical field (0.5Vcm(-1), DC) was kept connected for 6months without addition of water, leading to dewatering and warming of the soil.Results and discussionIn contrast to the situation with the original wet soil, VOCs, in lab conditions, were found to volatilize very efficiently from the dewatered soil. When the soil vapor extraction treatment was renewed using perforated tubing installed horizontally at ca 1m depth in the dewatered soil at the contaminated site, the treatment was efficient and the soil was decontaminated in 5months. The final VOC concentrations were on average 190mgkg(-1) (n=13) with the highest value of 700mgkg(-1) at one hotspot. After a risk evaluation, the site was concluded to be sufficiently clean for industrial use.ConclusionsSince with many former fuel stations, the contamination consists of both volatile fractions that are difficult to degrade by biological means and heavier compounds for which biostimulation is often suitable, a combination of different methods may be worth pursuing.Peer reviewe

Integrity of APS, HVOF and HVAF sprayed NiCr and NiCrBSi coatings based on the tensile stress-strain response

The interlamellar cohesion of thermal spray coatings influences greatly their mechanical properties and ability to use coatings in different loading conditions and wear/erosion resistance. In the present study, micro-tensile testing of free-standing coatings was utilized to evaluate the mechanical response of thermally sprayed coatings. In addition, the longitudinal uniaxial fracture strength of free-standing coatings could be determined by a tensile test. The coating materials studied were NiCr and NiCrBSi coatings sprayed by atmospheric plasma spraying (APS), high velocity oxy-fuel (HVOF), and high velocity air-fuel (HVAF) processes. The different materials used for the coatings sprayed by different methods yield different microstructures, different stress-strain relation in tensile testing. Different tensile test response was found to be related to cohesion strength between lamellas, and thus was affecting the cavitation erosion wear. The effect of other factors such as hardness and residual stresses on cavitation resistance were also discussed. Such results are crucial to understand the suitability of microstructures obtained by TS processes for different wear conditions.publishedVersionPeer reviewe

Semantic Finlex : Transforming, Publishing, and Using Finnish Legislation and Case Law As Linked Open Data on the Web

Peer reviewe

Effect of inactivated nature-derived microbial composition on mouse immune system

Introduction: The hygiene hypothesis suggests that decrease in early life infections due to increased societal-level hygiene standards subjects one to allergic and autoimmune diseases. In this report, we have studied the effect of sterilized forest soil and plant-based material on mouse immune system and gut microbiome. Methods: Inbred C57Bl/6 mice maintained in normal sterile environment were subjected to autoclaved forest soil-derived powder in their bedding for 1 h a day for 3 weeks. Immune response was measured by immune cell flow cytometry, serum cytokine enzyme-linked immunoassay (ELISA) and quantitative polymerase chain reaction (qPCR) analysis. Furthermore, the mouse gut microbiome was analyzed by sequencing. Results: When compared to control mice, mice treated with soil-derived powder had decreased level of pro-inflammatory cytokines namely interleukin (IL)-17F and IL-21 in the serum. Furthermore, splenocytes from mice treated with soil-derived powder expressed less IL-1b, IL-5, IL-6, IL-13, and tumor necrosis factor (TNF) upon cell activation. Gut microbiome appeared to be stabilized by the treatment. Conclusions: These results provide insights on the effect of biodiversity on murine immune system in sterile environment. Subjecting mice to soil-based plant and microbe structures appears to elicit immune response that could be beneficial, for example, in type 2 inflammation-related diseases, that is, allergic diseases.Peer reviewe

Ihonsuojauksen ja turvallisten työtapojen merkitys MDI-uretaanityössä

Tämän tutkimuksen avulla saatiin uutta tietoa ihosuojauksen ja turvallisten työtapojen merkityksestä MDI-uretaanityössä.1

Protocol for motor and language mapping by navigated TMS in patients and healthy volunteers; workshop report

Navigated transcranial magnetic stimulation (nTMS) is increasingly used for preoperative mapping of motor function, and clinical evidence for its benefit for brain tumor patients is accumulating. In respect to language mapping with repetitive nTMS, literature reports have yielded variable results, and it is currently not routinely performed for presurgical language localization. The aim of this project is to define a common protocol for nTMS motor and language mapping to standardize its neurosurgical application and increase its clinical value. The nTMS workshop group, consisting of highly experienced nTMS users with experience of more than 1500 preoperative nTMS examinations, met in Helsinki in January 2016 for thorough discussions of current evidence and personal experiences with the goal to recommend a standardized protocol for neurosurgical applications. nTMS motor mapping is a reliable and clinically validated tool to identify functional areas belonging to both normal and lesioned primary motor cortex. In contrast, this is less clear for language-eloquent cortical areas identified by nTMS. The user group agreed on a core protocol, which enables comparison of results between centers and has an excellent safety profile. Recommendations for nTMS motor and language mapping protocols and their optimal clinical integration are presented here. At present, the expert panel recommends nTMS motor mapping in routine neurosurgical practice, as it has a sufficient level of evidence supporting its reliability. The panel recommends that nTMS language mapping be used in the framework of clinical studies to continue refinement of its protocol and increase reliability.Peer reviewe

Genomic prediction of alcohol-related morbidity and mortality

While polygenic risk scores (PRS) have been shown to predict many diseases and risk factors, the potential of genomic prediction in harm caused by alcohol use has not yet been extensively studied. Here, we built a novel polygenic risk score of 1.1 million variants for alcohol consumption and studied its predictive capacity in 96,499 participants from the FinnGen study and 39,695 participants from prospective cohorts with detailed baseline data and up to 25 years of follow-up time. A 1 SD increase in the PRS was associated with 11.2 g (=0.93 drinks) higher weekly alcohol consumption (CI = 9.85-12.58 g, p = 2.3 x 10(-58)). The PRS was associated with alcohol-related morbidity (4785 incident events) and the risk estimate between the highest and lowest quintiles of the PRS was 1.83 (95% CI = 1.66-2.01, p = 1.6 x 10(-36)). When adjusted for self-reported alcohol consumption, education, marital status, and gamma-glutamyl transferase blood levels in 28,639 participants with comprehensive baseline data from prospective cohorts, the risk estimate between the highest and lowest quintiles of the PRS was 1.58 (CI = 1.26-1.99, p = 8.2 x 10(-5)). The PRS was also associated with all-cause mortality with a risk estimate of 1.33 between the highest and lowest quintiles (CI = 1.20-1.47, p = 4.5 x 10(-8)) in the adjusted model. In conclusion, the PRS for alcohol consumption independently associates for both alcohol-related morbidity and all-cause mortality. Together, these findings underline the importance of heritable factors in alcohol-related health burden while highlighting how measured genetic risk for an important behavioral risk factor can be used to predict related health outcomes.Peer reviewe