In-situ X-ray Video Microscopy Studies of Al-Si Eutectic Solidification

In-situ studies of Al-Si eutectic growth has been carried out for the first time by X-ray video microscopy during directional solidification of Al-Si-Cu alloys with and without Sr-addtions. The unmodified eutectics showed distinctive non-isothermal growth dynamics, where Si-crystals attained needle-like tip morphologies and progressed under significantly higher undercooling than Al, leading to formation of an irregular eutectic with Si as the leading phase and subsequent nucleation of Al on the Si-surfaces. In the Sr-modified alloys, the eutectic reaction was found to be strongly suppressed, occurring with low nucleation frequencies at undercoolings in the range 10-18 K. In the Cu-enriched melt, the eutectic front was found to attain meso-scale interface perturbations evolving into equiaxed cellular rosettes in order to accommodate to the long-range redistribution of Cu from the composite eutectic interface. The eutectic front also attained short-range microscale interface perturbations consistent with characteristics of a fibrous Si growth, however further improvements in spatial resolution is required in order to study microscale structure formation in greater detail. Evidence was found in support of Si-nucleation occurring on potent particles suspended in the melt. Yet, both with Sr- modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form on the Si-particles. To what extent nucleation mechanisms in the Cu-enriched systems are transferable to binary or commercial Al-Si alloys remains uncertain

Nucleation and Growth Dynamics of the α-Al / β-Al5FeSi Eutectic in a Complex Al-Si-Cu-Fe Alloy

Secondary-sourced recycled aluminium alloys can exhibit high levels of different impurities. It is well known that the presence of iron, the most common impurity, can lead to the formation of hard and brittle intermetallic phases which are detrimental to the machining properties and the mechanical behaviour of the material in service. The purpose of this work is to study the nucleation and growth of the β-Al5FeSi intermetallic phase in the framework of the eutectic reaction: Liquid → α-Al + β-Al5FeSi. In situ X-ray microtomography has been used to investigate the formation of the irregular eutectic β-phase plates during the solidification at low cooling rate of an Al-8Si-4Cu-0.8Fe alloy. The results show that only a few plates form, nucleating early near the sample surface. Next, growth occurs very rapidly in the principal growth direction and slowly in the thickness direction. The plates are highly branched and appear to form as a divorced eutectic, i.e. not coupled with the α-Al. These features are inconsistent with the common irregular eutectic solidification theory based on the Jackson and Hunt model

Comparison of visual and molecular taxonomic methods to identify ichthyoplankton in the North Sea

The North Sea is an important spawning and nursery ground for many demersal and pelagic fishes whose spawning areas are largely overlapping in time and space. This makes ichthyoplankton visual identification from the various species particularly challenging. Despite historically intensive research in the area, detailed information on spawning sites and times for many taxa, are incomplete. To update and detail the mapping of fish spawning performance and distribution in the central and northern regions of the North Sea, the performance of a visual method and a molecular taxonomic approach used for taxonomic classification of ichthyoplankton was evaluated. Samples of fish eggs and larvae were collected regularly and in parallel at different latitudinal locations from the central to the northern North Sea, including a sample with 78 larvae used for direct comparison between both methods. A total of 5332 individuals were inspected and 36 different species were identified. The visual processing identified 89% of the collected larvae to species level, however, for the eggs the taxonomic resolution was lower with only 5% identified to species level. In comparison to visual identification, molecular barcoding gave higher precision of identification for larvae and especially for the eggs. For the larvae, 98% were assigned to species level, and for the eggs 94% were assigned to species level. We find that molecular barcoding is more effective and precise in taxonomic identification of both eggs and larvae to species level. However, visual identification is still needed to provide information on the developmental stages.publishedVersio

Assessment of Fish Spawning in the North Sea; Final Project Report of KINO-2, 2017–2021

Increased and updated knowledge of reproductive strategies of fish is crucial to optimize the temporal and spatial planning for conducting seismic surveys; in order to reduce its potential negative ecosystems impacts. The overall goal of this study is to improve our knowledge about the spawning times of the major North Sea fish stocks.publishedVersio

Microstructure control in Sn-0.7mass%Cu alloys

Soldering alloys based oft the Sn-Cu alloy system are amongst the most favourable lead-free alternatives due to a range of attractive properties. Trace additions of Ni have been found to significantly improve the soldering characteristics of these alloys (reduced bridging etc.). This paper examines the mechanisms underlying the improvement in soldering properties of Sn-0.7 mass%Cu eutectic alloys modified with concentrations of Ni ranging front 0 to 1000 ppm. The alloys were investigated by thermal analysis during solidification, as well as optical/SEM microanalyses of fully solidified samples anti samples quenched during solidification. It is concluded that Ni additions dramatically alter the nucleation patterns and solidification behaviour of the Sn-Cu6Sn5 eutectic anti that these changes are related to the superior soldering characteristics of the Ni-modified Sn-0.7 mass%Cu alloys

Mapping of Fish Spawning in the North Sea; Report of the “KINO-2” Project for 2019

Increased and updated knowledge of reproductive strategies of fish is crucial to optimize the temporal and spatial planning for conducting seismic surveys; in order to reduce its potential negative ecosystems impacts. The overall goal of this study is to improve our general knowledge about spawning areas of major North Sea fish stocks, including their spawning behavior and spawning period. This report describes the methodology, preliminary results and experiences gained during the data sampling period August 2017 to December 2019. Molecular barcode and traditional visual taxonomic analyses were performed on eggs and larvae, systematically collected with plankton nets along a south to north axis in the North Sea. In total, 201 samples have been analysed from which 35 different fish taxa are identified. Based on historic data and previously published literature, our results agree with the expected number of the most prevalent fish species breeding in the North Sea. Both the taxonomic and molecular methods used, demonstrate robust and similar results in the identification of taxonomic groups. The results further demonstrate that the molecular taxonomic approach is more appropriate for identification to species levels for most taxonomic groups, whilst the identification of egg and larvae developmental stages can only be performed using the visual taxonomic method. The two techniques have the potential of complementing each other to provide a detailed description of the annual fish spawning cycle for the main North Sea species. Our results demonstrate that the fish species diversity increase northwards, but here the spawning season is more concentrated. We have also identified new species spawning in the area, traditionally found more to the south or west of our study area. To improve the spatial and temporal statistical data resolution required for achieving sufficient scientific evidence as basis for producing robust advice in timing of seismic surveys, modifications to the sampling protocol and equipment was made during 2019. Expectantly, this potential proves to work over the coming annual reproduction cycle. Our study also confirms that the study area represents a highly dynamic environment, thus we strongly recommend considering extending the time period for data collection, beyond what is planned so far (due out August 2020) and an expansion of the geographical coverage to include regions also further north and west.publishedVersio

Mapping of fish spawning in the North Sea — Report of the KINO-2 project for 2018

Increased and updated knowledge of reproductive strategies of fish is crucial to optimize the temporal and spatial planning for conducting seismic surveys; in order to reduce its potential negative ecosystems impacts. The overarching goal of this study is to investigate the current spawning times and locations for the North Sea fish stocks. Molecular barcode and traditional visual taxonomic analyses were performed on eggs and larvae, systematically collected with plankton nets along a south to north axis in the North Sea. This report describes the establishments of methodology employed and preliminary results based on samples collected during August 2017 to September 2018. In total, 129 samples have been analysed from which 22 different fish taxa are identified. Based on historic data and published literature, our results agree with the expected number of the most prevalent fish species breeding in the North Sea. Both the taxonomic and molecular methods used, demonstrate similar results in the identification of taxonomic groups. The results further demonstrate that the molecular taxonomic approach is more appropriate for identification to species levels for some taxonomic groups, whilst the identification of egg and larvae developmental stages can only be performed using the visual taxonomic method. The two techniques complement each other to provide a detailed description of the annual fish spawning cycle for the main North Sea species. There are already emerging patterns evident in the results on the timing for breeding in some species at certain areas. However, improvements of the sampling methodology are still required, and an increased number of samples collected systematically over an extended time-period must be accomplished in order to provide appropriate data as basis for advice in timing of seismic surveys.publishedVersio

Treatment outcome of new culture positive pulmonary tuberculosis in Norway

BACKGROUND: The key elements in tuberculosis (TB) control are to cure the individual patient, interrupt transmission of TB to others and prevent the tubercle bacilli from becoming drug resistant. Incomplete treatment may result in excretion of bacteria that may also acquire drug resistance and cause increased morbidity and mortality. Treatment outcome results serves as a tool to control the quality of TB treatment provided by the health care system. The aims of this study were to evaluate the treatment outcome for new cases of culture positive pulmonary TB registered in Norway during the period 1996–2002 and to identify factors associated with non-successful treatment. METHODS: This was a register-based cohort study. Treatment outcome was assessed according to sex, birthplace, age group, isoniazid (INH) susceptibility, mode of detection and treatment periods (1996–1997, 1998–1999 and 2000–2002). Logistic regression was also used to estimate the odds ratio for treatment success vs. non-success with 95% confidence interval (CI), taking the above variables into account. RESULTS: Among the 655 patients included, the total treatment success rate was 83% (95% CI 80%–86%). The success rates for those born in Norway and abroad were 79% (95% CI 74%–84%) and 86% (95% CI 83%–89%) respectively. There was no difference in success rates by sex and treatment periods. Twenty-two patients (3%) defaulted treatment, 58 (9%) died and 26 (4%) transferred out. The default rate was higher among foreign-born and male patients, whereas almost all who died were born in Norway. The majority of the transferred out group left the country, but seven were expelled from the country. In the multivariate analysis, only high age and initial INH resistance remained as significant risk factors for non-successful treatment. CONCLUSION: Although the TB treatment success rate in Norway has increased compared to previous studies and although it has reached a reasonable target for treatment outcome in low-incidence countries, the total success rate for 1996–2002 was still slightly below the WHO target of success rate of 85%. Early diagnosis of TB in elderly patients to reduce the death rate, abstaining from expulsion of patients on treatment and further measures to prevent default could improve the success rate further