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Integrity Experiments for Geological Carbon Storage (GCS) in Depleted Hydrocarbon Reservoirs: Wellbore Components under Cyclic CO2 Injection Conditions
Full text linkIntegrity of wellbores and near wellbore processes are crucial issues in geological carbon storage (GCS) projects as they both define the confinement and injectivity of CO2. For the proper confinement of CO2, any flow of CO2 along the wellbore trajectory must be prevented using engineered barriers. The effect of cyclic stimuli on wellbore integrity, especially in the context of GCS projects, has been given less attention. In this study, the effect of pressure- and temperature-cycling on two types of wellbore composites (i.e., casing-cement and cement-caprock) have been investigated experimentally in small- and large-scale laboratory setups. The experiments have been carried out by measuring the effective permeability of the composites under pressure and thermal cyclic conditions. Furthermore, the permeability of individual samples (API class G and HMR+ cement and caprock) was measured and compared to the permeability of the composites. The results indicate that the permeability of API class G cement when exposed to CO2 is in the order of 10−20 m2 (10−5 mD) as a result of the chemical reaction between the cement and CO2. In addition, the tightness of the composite cement–rock has been confirmed, while the permeability of the composite casing–cement falls within the acceptable range for tight cement and the CO2 flow was identified to occur through or close to the interface casing–cement. Results from thermal cycling within the range −9 to 14 °C revealed no significant effect on the integrity of the bond casing–cement. In contrast, pressure cycling experiments showed that the effective pressure has a larger influence on the permeability. The potential creation of micro-cracks under pressure variations may require some time for complete closing. In conclusion, the pressure and temperature cycling from this study did not violate the integrity of the casing–cement composite sample as the permeability remained low and within the acceptable range for wellbore cement.Integrity Experiments for Geological Carbon Storage (GCS) in Depleted Hydrocarbon Reservoirs: Wellbore Components under Cyclic CO2 Injection ConditionspublishedVersio
Impact of mantle convection and dynamic topography on the Cenozoic paleogeography of Central Eurasia and the West Siberian Seaway
Full text linkThe West Siberian Seaway connected the Tethys to the Arctic Ocean in the Paleogene and played an important role for Eurasian-Arctic biogeography, ocean circulation, and climate. However, the paleogeography and geological mechanisms enabling the seaway are not well constrained, which complicates linking the seaway evolution to paleoenvironmental changes. Here, we investigate the paleogeography of the Peri-Tethys realms for the Cenozoic time (66–0 Ma), including the West Siberian Seaway, and quantify the influence of mantle convection and corresponding dynamic topography. We start by generating continuous digital elevation models for Eurasia, Arabia, and Northern Africa, by digitizing regional paleogeographic maps and additional geological information and incorporate them in a global paleogeography model with nominal million-year resolution. Then we compute time-dependent dynamic topography for the same time interval and find a clear correlation between changes in dynamic topography and the paleogeographic evolution of Central Eurasia and the West Siberian Seaway. Our results suggest that mantle convection played a greater role in Eurasian paleogeography than previously recognized. Mantle flow may have influenced oceanic connections between the Arctic and global ocean providing a link between deep mantle convection, surface evolution, and environmental changes. Our reconstructions also indicate that the Arctic Ocean may have been isolated from the global ocean in the Eocene, even if the West Siberian Seaway was open, as the Peri-Tethys – Tethys connection was limited, and the Greenland-Scotland Ridge was a landbridge.publishedVersio
Effect of short-term exposure to the strobilurin fungicide dimoxystrobin: Morphofunctional, behavioural and mitochondrial alterations in Danio rerio embryos and larvae
Full text linkStrobilurins, among the most used fungicides worldwide, are considered non-toxic to mammals and birds, but there is growing evidence that these compounds are highly toxic to aquatic species. Dimoxystrobin has been included in the 3rd Watch List of the European Commission, and it has been classified as very toxic to aquatic life. However, previous studies focused on acute toxicity and only two reports are available on its impact on fish, and none on its effects during the early life stages. Here, we evaluated for the first time the effects induced on zebrafish embryos and larvae by two dimoxystrobin sublethal concentrations (6.56 and 13.13 μg/L) falling in the range of predicted environmental concentrations. We demonstrated that short-term exposure to dimoxystrobin may exert adverse effects on multiple targets, inducing severe morphological alterations. Moreover, we showed enhanced mRNA levels of genes related to the mitochondrial respiratory chain and ATP production. Impairment of the swim bladder inflation has also been recorded, which may be related to the observed swimming performance alterations.publishedVersio
A Synthesis of Global Coastal Ocean Greenhouse Gas Fluxes
Full text linkThe coastal ocean contributes to regulating atmospheric greenhouse gas concentrations by taking up carbon dioxide (CO2) and releasing nitrous oxide (N2O) and methane (CH4). In this second phase of the Regional Carbon Cycle Assessment and Processes (RECCAP2), we quantify global coastal ocean fluxes of CO2, N2O and CH4 using an ensemble of global gap-filled observation-based products and ocean biogeochemical models. The global coastal ocean is a net sink of CO2 in both observational products and models, but the magnitude of the median net global coastal uptake is ∼60% larger in models (−0.72 vs. −0.44 PgC year−1, 1998–2018, coastal ocean extending to 300 km offshore or 1,000 m isobath with area of 77 million km2). We attribute most of this model-product difference to the seasonality in sea surface CO2 partial pressure at mid- and high-latitudes, where models simulate stronger winter CO2 uptake. The coastal ocean CO2 sink has increased in the past decades but the available time-resolving observation-based products and models show large discrepancies in the magnitude of this increase. The global coastal ocean is a major source of N2O (+0.70 PgCO2-e year−1 in observational product and +0.54 PgCO2-e year−1 in model median) and CH4 (+0.21 PgCO2-e year−1 in observational product), which offsets a substantial proportion of the coastal CO2 uptake in the net radiative balance (30%–60% in CO2-equivalents), highlighting the importance of considering the three greenhouse gases when examining the influence of the coastal ocean on climate.publishedVersio
Social withdrawal behaviour in Nepalese infants and the relationship with future neurodevelopment; a longitudinal cohort study
Full text linkBackground Social withdrawal in infants may be a signal of distress and a precursor for non-optimal development. Objective To examine the relationship between infant social withdrawal and neurodevelopment up to 4 years in Nepalese children. Methods A total of 597 Nepalese infants 6–11 months old were assessed with the modified Alarm Distress Baby Scale (m-ADBB), and of these, 527 with the Bayley Scales of Infant and Toddler Development 3rd edition (Bayley-III) during early childhood, and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV) and NEPSY-II subtests at 4 years. We examined whether social withdrawal defined by the m-ADBB was associated with neurodevelopmental scores in regression models. Results Children socially withdrawn in infancy had lower Bayley-III language scores (-2.6 (95% CI -4.5, -0.7)) in early childhood. This association seems to be driven by the expressive communication subscale (-0.7 (95% CI -1.0, -0.3)), but not the receptive communication subscale (-0.2 (95% CI -0.6, 0.1)). There were no differences in the other Bayley-III scores or the WPPSI-IV and NEPSY-II scores at 4 years in children who were socially withdrawn or not. Conclusion Social withdrawal in infancy was reflected in early language development but not cognitive functioning at 4 years.publishedVersio
Hva forklarer kostnads- og tidsoverskridelser i bypakker? En undersøkelse av utvalgte samferdselstiltak i Bergen, i Trondheim og på Nord-Jæren
Full text linkI dette prosjektet har vi undersøkt hvile faktorer som fremmer og hemmer vellykket iverksetting av samferdselstiltak. Til sammen er iverksettingen av seks ulike infrastrukturtiltak undersøkt i hhv Bergen, Trondheim og på Nord-Jæren. Oppmerksomheten er rettet mot hvilke faktorer som kan belyse hvorfor budsjett og framdriftsplan holdes eller ikke. Undersøkelsen er gjennomført ved dokumentstudier og intervju. Undersøkelsen viser at tre av tiltakene har overskredet budsjettene, ett av tiltakene ligger innenfor budsjett, mens to av tiltakene ikke er ferdigstilt enda. For to av tiltakene er det flere års forsinkelser, mens det for de andre er mindre forsinkelser. En viktig årsak til budsjettoverskridelse i planleggingsfasen er at flere av prosjektene har vært mer komplisert enn antatt eller at man har mangler kunnskap om bygging av den spesifikke typen prosjekter i urbane områder. Manglende kontroll og dermed for sein iverksettelse av korrigerende tiltak er en annen årsak til budsjettoverskridelse. Generelt sett er også omorganisering samtidig med iverksetting uheldig. I anleggsfasen framstår manglende kunnskap om grunnforhold som en viktig årsak til budsjettoverskridelse. Dette kan medføre behov for ny prosjektering og kostnadssprekk i mange ledd i tillegg til forsinkelser. Økte priser på stål og betong grunnet eksterne forhold (Covid-19) og Ukraina-krigen har også bidratt til økte kostnader for flere av samferdselstiltakene.Hva forklarer kostnads- og tidsoverskridelser i bypakker? En undersøkelse av utvalgte samferdselstiltak i Bergen, i Trondheim og på Nord-JærenpublishedVersio
Calculating Bayesian model evidence for porous-media flow using a multilevel estimator
Full text linkWe consider calculation of the Bayesian model evidence, which is an essential component in realistic uncertainty quantification. The main motivation is large-scale porous-media-flow problems, where plain Monte-Carlo (MC) integration is computationally infeasible. We propose a simplistic multilevel (ML) estimator and argue why this estimator is expected to perform well within a certain problem class, and point out that many important problems, including many porous-media-flow problems, belong to this class. Four test cases are utilized to assess the performance of the proposed ML estimator. Test cases I and II contain two strongly linked toy models, but only Test case II belongs to the problem class where the proposed ML estimator is expected to perform well. Test cases III and IV are concerned with single-phase and two-phase porous-media flows, respectively. The results show that the ML estimator clearly and consistently outperforms MC integration in Test cases II, III, and IV, while this is not the case for Test case I.publishedVersio
Vurdering av overlevelsen til laksesmolt i Modalselva ved bruk av telemetri
No full textpublishedVersio
Siltmobilisering og gassmetning i Modalselva august 2023 - Evaluering av mulig effekt på fiskebestand og bunndyrsamfunn
Full text linkDet ble observert kraftig blakket vann som kom ut fra Hellandsfoss kraftverk om kvelden 25. august 2023. Årsaken var trolig at løsmasser (silt) ble mobilisert ved tømming og påfylling av vann i tunnelen i forbindelse med inspeksjon inne i tunnelen mellom Almelid og Hellandsfoss. Dette blakket vannet betydelig under oppstart av kraftstasjonen. Det ble tatt vannprøve i regi av elveeierlaget og meldt fra om hendelsen til Statsforvalter. I forbindelse med prøvefiske etter laks i perioden 14-17 september, ble det kun fanget 2 laks. NORCE LFI har fulgt opp hendelsen med snorkling, undersøkelser av bunndyr, gytefisk og ungfisk. Data fra gassmålere i kraftutløpet og analysesvar fra vannprøve er gjennomgått som en del av disse oppfølgende undersøkelsene.Siltmobilisering og gassmetning i Modalselva august 2023 - Evaluering av mulig effekt på fiskebestand og bunndyrsamfunnpublishedVersio
Factors affecting communication during telephone triage in medical call centres: a mixed methods systematic review
Full text linkBackground Telephone triage is used to optimise patient flow in emergency primary healthcare. Poor communication can lead to misunderstandings and compromise patient safety. To improve quality, a comprehensive understanding of factors affecting communication in medical call centres in primary care is needed. The aim of this review was to identify such factors and to describe how they affect communication during telephone triage. Method A mixed-method systematic review was performed. In April 2021 and June 2023, MEDLINE, Embase, CINAHL, and Web of Science were searched for original studies describing communication during telephone triage in primary care medical call centres handling all types of medical problems from an unselected population. All studies were screened by two authors, blinded to each other’s decisions. Disagreements were resolved by a third author. A framework was created by the thematic synthesis of the qualitative data and later used to synthesise the quantitative data. By using convergent integrated synthesis, the qualitative and quantitative findings were integrated. The Mixed Methods Appraisal Tool was used to assess methodological limitations. Results Out of 5087 studies identified in the search, 62 studies were included, comprising 40 qualitative, 16 quantitative and six mixed-method studies. Thirteen factors were identified and organised into four main themes: organisational factors, factors related to the operator, factors related to the caller and factors in the interaction. Organisational factors included availability, working conditions and decision support systems. Factors related to the operator were knowledge and experience, personal qualities and communication strategies. Factors related to the caller were individual differences and the presented medical problem. Factors in the interaction were faceless communication, connection between operator and caller, third-person caller and communication barriers. The factors seem interrelated, with organisational factors affecting all parts of the conversation, and the operator’s communication in particular. Conclusion Many factors affect the structure, content, and flow of the conversation. The operators influence the communication directly but rely on the organisation to create a working environment that facilitates good communication. The results are mainly supported by qualitative studies and further studies are needed to explore and substantiate the relevance and effect of individual factors.publishedVersio