Johann-type laboratory-scale x-ray absorption spectrometer with versatile detection modes

We present a low-cost laboratory X-ray absorption spectrometer that uses a conventional X-ray tube source and bent Johann-type crystal monochromators. The instrument is designed for X-ray absorption spectroscopy studies in the 4-20 keV range which covers most K edges of 3d transition metals and L edges of 5d transition metals and actinides. The energy resolution is typically in the range of 1-5 eV at 10 keV depending on the crystal analyser and the Bragg angle. Measurements can be performed in transmission, fluorescence, and imaging modes. Due to its simple and modular design, the spectrometer can be modified to accommodate additional equipment and complex sample environments required for in situ studies. A showcase of various applications is presented. Published under license by AIP Publishing.Peer reviewe

Simulation-Based Study of Control Strategies for Beating of Human Cardiomyocyte Cultures

Peer reviewe

Laboratory-scale x-ray absorption spectroscopy of 3d transition metals in inorganic thin films

In this paper we present laboratory-scale X-ray absorption spectroscopy applied to the research of nanometer-scale thin films. We demonstrate the Cu K edge X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) of CuI and CuO thin films grown with atomic layer deposition. Film thicknesses in the investigated samples ranged from 12 to 248 nm. Even from the thinnest films, XANES spectra can be obtained in 5-20 minutes and EXAFS in 1-4 days. In order to prove the capability of laboratory-based XAS for in situ measurements on thin films, we demonstrate an experiment on in situ oxidation of a 248 nm thick CuI film at a temperature of 240 degrees C. These methods have important implications for novel and enhanced possibilities for inorganic thin film research.Peer reviewe

Kaivosten stressitestit 2013

Talvivaaran kaivoksella marraskuussa 2012 sattuneen vesistövahingon jälkeen Suomen hallitus päätti, että kaivoksille tehdään stressitestit. Ympäristöministeriö asetti tammikuussa 2013 kaivosten ympäristöturvallisuus -viranomaistyöryhmän (KYTU), jonka tehtävänä oli arvioida viranomaisten tehtäviä, toimivaltaa, ohjauskeinoja ja yhteistyötä kaivosten ympäristövahinkojen ehkäisemisen kannalta. Eräänä työkaluna KYTU-työryhmällä oli kaivosten stressitestit. Stressitestauksen ensimmäisessä vaiheessa kaivokset arvioivat itse toimintaansa kysymyslomakkeen avulla. Tämän jälkeen ympäristöministeriön nimeämä asiantuntijaryhmä kävi läpi kaivosten itsearvioinnit ja antoi niistä palautetta. Stressitestien kysymyslomakkeessa oli kuvattu seitsemän riskitilannetta, joihin liittyi yhteensä 15 kysymystä. Testattaviksi riskitilanteiksi valittiin mm. poikkeuksellisen suuri sadanta, joka vaikeuttaa vesien käsittelyä, varastointia ja poisjohtamista sekä patoaltaiden rakenteet, jotka eivät kestä poikkeuksellisen suuren vesimäärän aiheuttamaa rasitusta. Stressitestikysely lähetettiin 21 kaivokselle ja rikastamolle. Testattavaksi tulivat kaikki metallimalmikaivokset ja metallimalmirikastamot sekä niiden lisäksi myös muutamia teollisuusmineraalikaivoksia ja -rikastamo sekä karbonaattikaivoksia, jotka käsittelevät runsaasti kemikaaleja tai joiden jäte- tai vesiallaspadot voisivat onnettomuuden sattuessa aiheuttaa vaaraa ihmiselle tai ympäristölle. Vastaukset saatiin asetettuun määräaikaan mennessä 20 kohteesta. Vastaukset sisälsivät myös kuvauksia olemassa olevista hyvistä käytännöistä ja kehittämisehdotuksia. Stressitestin perusteella esitettyihin poikkeustilanteisiin on kokonaisuudessaan paneuduttu ja varauduttu kaivoksilla suhteellisen hyvin. Erityisesti patorakenteiden valvonta, pato- ja pohjavaurioiden hätäkorjaukseen varautuminen, haitallisten päästöjen tunnistaminen, sähkökatkoksiin ja ilkivaltaan varautuminen sekä poikkeustilanteista tiedottaminen tuntuivat olevan lähes kaikilla hyvin hallinnassa. Sen sijaan vesien hallinnassa, pohjarakenteiden valvonnassa, poikkeuksellisten päästöjen havaitsemisessa ja hallinnassa sekä kaivannaisjätteiden kemiallisen muuttumisen tunnistamisessa, ymmärtämisessä ja tarkkailussa oli puutteita. Vesimäärien hallinnassa on tärkeää ennakointi mm. sää- ja vesistöennusteiden sekä säähavaintojen perusteella. Vara-allaskapasiteettia tulee olla riittävästi, ettei tulva- yms. tilanteissa jää ylimääräisen veden ainoaksi hallintakeinoksi vesien juoksuttaminen vesistöön. Vaatimus prosessinomaisesta vedenpuhdistuksesta olisi tarpeen etenkin uusia kaivoksia luvitettaessa. Jokaisella toimijalla tulisi olla käytössään toimivat varajärjestelmät pato- ja pohjavuotojen varalle. Tarkkailuun on suositeltavaa sisällyttää pato- ja pohjarakenteiden toimivuuden valvomiseksi suotoveden määrän seurannan ohella kemiallisen laadun seurantaa ja lisätä pohjaveden laadun tarkkailua jätealtaan tai haitallisia aineita sisältävien vesialtaiden ympäristöstä. Uusien jätealtaiden pohjarakenteiden valvontaan tulee kehittää ja ottaa käyttöön päivittäisten tarkkailukierrosten lisäksi ennakoivia seurantajärjestelmiä, joilla mahdolliset kalvojen rikkoontumiset ja vuodot voidaan havaita varhain. Tässä raportissa esitettyjen yleisten ja kaivoskohtaisten huomioiden sekä kaivosten omissa vastauksissa esiintuotujen parantamisehdotusten tarkastelua suositellaan hyödynnettäväksi kaivosten omien kehittämissuunnitelmien sekä viranomaisyhteistyössä käytävien keskustelujen pohjana

Operando Laboratory-Based Multi-Edge X-Ray Absorption Near-Edge Spectroscopy of Solid Catalysts

Laboratory-based X-ray absorption spectroscopy (XAS) and especially X-ray absorption near-edge structure (XANES) offers new opportunities in catalyst characterization and presents not only an alternative, but also a complementary approach to precious beamtime at synchrotron facilities. We successfully designed a laboratory-based setup for performing operando , quasi-simultaneous XANES analysis at multiple K edges, more specifically, operando XANES of mono-, bi-, and trimetallic CO 2 hydrogenation catalysts containing Ni, Fe, and Cu. Detailed operando XANES studies of the multi-element solid catalysts revealed metal-dependent differences in the reducibility and re-oxidation behavior and their influence on the catalytic performance in CO 2 hydrogenation. The applicability of operando laboratory-based XANES at multiple K edges paves the way for advanced multi-element catalyst characterization complementing detailed studies at synchrotron facilities.Peer reviewe

Operando Laboratory-based Multi-edge X-ray Absorption Near-Edge Spectroscopy of Solid Catalysts

Laboratory-based X-ray absorption spectroscopy (XAS) and especially X-ray absorption near-edge structure (XANES) offers new opportunities in catalyst characterization and presents not only an alternative, but also a complementary approach to precious beamtime at synchrotron facilities. We successfully designed a laboratory-based setup for performing operando , quasi-simultaneous XANES analysis at multiple K edges, more specifically, operando XANES of mono-, bi-, and trimetallic CO 2 hydrogenation catalysts containing Ni, Fe, and Cu. Detailed operando XANES studies of the multi-element solid catalysts revealed metal-dependent differences in the reducibility and re-oxidation behavior and their influence on the catalytic performance in CO 2 hydrogenation. The applicability of operando laboratory-based XANES at multiple K edges paves the way for advanced multi-element catalyst characterization complementing detailed studies at synchrotron facilities

The Chemical Path of Eroded Soil Field Soil from Field to Bottom Sediment with K-edge X-ray Absorption Near Edge Spectroscopy

Eutrophication is a global challenge, where chemical processes in bottom sediments play a key role. Yet, eutrophication science lacks understanding of the role of terrestrial matter on the processes that mobilize or immobilize phosphorus, a central algal nutrient, in sediments. Eroded field soil is carried into sea by runoff and soil is settled on the bottom and then buried. During burial the sediment microbial processes change the redox-conditions which affect the chemistry of settled soil. Here, methods were developed to follow the evolution of the chemical state of soil during burial with iron K-edge X-ray absorption near edge spectroscopy, with a novel home-laboratory based spectrometer. The chemical state of soil, and especially the chemistry of iron is linked to the release and binding of phosphorus in bottom sediments. The chemical path of field soil was simulated with anaerobic incubation, where organic carbon and sulfates were added to represent various sea bottom conditions. In order to measure the spectra of soil-water mixtures, a sample preparation method was developed, where the sample is gellified in both aerobic and anaerobic conditions. The gel makes the suspension uniform and homogeneous. We also developed a sample environment for anaerobic measurements. The measured spectra were compared with spectra obtained from reference iron compounds and the iron species were quantified. The sulfate and addition of organic carbon enhanced the formation of iron sulfides, causing iron bound phosphorus to be released to water. As expected, the release of phosphorus was higher in anaerobic conditions than in aerobic conditions. The addition of organic carbon and sulfate enhanced the formation of iron sulfides, causing iron bound phosphorus to be released to the aquatic system. The results shed light on iron chemistry in anoxic sediments, which can be used in management of eutrophication

Operando Laboratory-based X-ray Absorption Spectroscopy : Guidelines for Newcomers in the Field

The new possibility to perform operando X-ray absorption spectroscopy (XAS) in the laboratory expands the potential field of applications towards a broad research community. These applications are multidisciplinary at heart and benefit from joint expertise from different fields, most importantly chemistry, physics, geology, and instrumentation. Hence, a development of collaboration networks that combine skills and knowhow from different fields is highly beneficial in this endeavor. As operando laboratory-based XAS constitutes a highly interesting, advanced, and powerful characterization technique, we provide in this article practical guidelines for newcomers in the field, who would like to employ it. Here, we will describe ten important steps towards a successful operando laboratory-based XAS experiment, which are not only useful for the catalysis community, but for a much wider audience from other research fields, such as environmental chemistry as well as battery and fuel cell research.Peer reviewe

Cardiomyocytes : Analysis of Temperature Response and Signal Propagation between Dissociated Clusters Using Novel Video-Based Movement Analysis Software

Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provide a great resource for functional cell and tissue models that can be applied in heart research, pharmaceutical industry, and future regenerative medicine. During cell model experiments, precise control of environmental parameters is important. Temperature is a fundamental parameter, and the acute effect of temperature on hiPSC-CM functions has previously been studied. This paper reports on long-term, systematic temperature response studies of hiPSC-CM cultures. The studies were conducted outside an incubator in a modular cell culturing system along with a temperature sensor plate (TSP) and a new beating analysis software (CMaN -cardiomyocyte function analysis tool). Temperature sensing at the actual cell location is challenging with bulky external sensors; however, a TSP with resistive microsensors provides an effortless solution. Experimental results showed that temperature nonlinearly affects the hiPSC-CM beating frequency with a Q10 temperature coefficient of 2.2. Both the active (contraction) and passive (relaxation) movements were influenced by temperature, and changes in the relaxation times were larger than the contraction times. However, the contraction amplitudes exhibited a greater spread of variation. We also present novel results on the visualization of hiPSC-CM contractile networking and non-invasive image-based measurement of signal propagation between dissociated CM clusters. Compared with previously reported tools, CMaN is an advanced and easy-to-use robust software. It is faster, more sensitive, computationally less expensive, and extracts six different signals of the contractile motion per process, providing at least one useful beating signal even in complex cases. The software also supports movement center detection and independent computation of the relaxation and contraction parameters.publishedVersionPeer reviewe

Operando Laboratory-based Multi-edge X-ray Absorption Near-Edge Spectroscopy of Solid Catalysts

Laboratory-based X-ray absorption spectroscopy (XAS) and especially X-ray absorption near-edge structure (XANES) offers new opportunities in catalyst characterization and presents not only an alternative, but also a complementary approach to precious beamtime at synchrotron facilities. We successfully designed a laboratory-based setup for performing operando , quasi-simultaneous XANES analysis at multiple K edges, more specifically, operando XANES of mono-, bi-, and trimetallic CO 2 hydrogenation catalysts containing Ni, Fe, and Cu. Detailed operando XANES studies of the multi-element solid catalysts revealed metal-dependent differences in the reducibility and re-oxidation behavior and their influence on the catalytic performance in CO 2 hydrogenation. The applicability of operando laboratory-based XANES at multiple K edges paves the way for advanced multi-element catalyst characterization complementing detailed studies at synchrotron facilities