Radiologisk utredning av primære hjernesvulster, nytte av nyere MR-teknikker.

Background and purpose: Medical imaging has come a long way from CT was invented in the 70s to today's CT- and MRI-technology. With today's technology we can produce detailed images of the brain tumor's size and location, damage to the blood-brain barrier and relationship to adjacent structures. The aim of the thesis is to present an overview of the modern MRI-techniques and the extent to which they provide additional information about a tumor's malignancy and growth pattern. Material and methods: The thesis is based on medical textbooks and articles found by systematic and non-systematic search in Pubmed/Medline and UpToDate, as well as articles and illustrations given by supervisor. Medical websites such as www.legehandboka.no (NEL) and www.tidsskriftet.no were also used. Results/Conclusions: Advanced MRI methods such as diffusion, perfusion and spectroscopy can give us a better understanding of the pathophysiological features of brain tumors. These methods can be seen as a complementary tool to conventional MRI. Thus, it is hoped that they can help to better differentiate and grade brain tumors as well as to distinguish between neoplastic and non-neoplastic lesions

Development of ecological concretes by recycling locally available by-products from the aluminum industry

Les émissions élevées de carbone dues à la production de ciment sont l'un des problèmes les plus critiques pour la durabilité du béton. Au cours des dernières décennies, l'utilisation d'ajouts cimentaires (SCMs) dans le béton est devenue très courante pour produire un béton durable. En outre, la demande mondiale croissante d'infrastructures entraîne aujourd'hui une surexploitation des ressources naturelles. En raison de la disponibilité limitée et variables des SCMs dans les régions, il existe aujourd'hui un besoin urgent d'explorer des SCMs qui sont disponibles localement pour la production d'un béton durable. Chaque année, 1,5 million de tonnes de brasques usées (SPL) sont générées comme déchets par les fonderies d'aluminium primaire dans le monde. Après traitement, le SPL devient un matériau inerte, appelé LCLL-ash dans cette étude. Les LCLL-ash sont riches en aluminium et en silice, ce qui leur confère des caractéristiques pour remplacer le ciment dans le béton. Tout d'abord, les LCLL-ash sont broyées à la même taille que les particules de ciment. 10 à 20% en masse du ciment, composant la pâte de ciment, est remplacé par le LCLL-ash broyée. Une petite quantité d'anhydrite synthétique (autre sous-produit lié à l'industrie de l'aluminium) est également ajoutée dans certains mélanges. Comme pour les bétons conventionnels, les résultats présentés montrent que la LCLL-ash a, au début, un effet de nucléation et une faible réaction pouzzolanique, tandis que la LCLL-ash change les produits d'hydratation avec l'apparition d'une nouvelle phase AFm-CO₃ et la formation accrue d'ettringite par rapport à la pâte pure. Un niveau de remplacement optimisé de 10% de ciment a pu être atteint sans affecter les propriétés micromécaniques. Deuxièmement, une étude préliminaire sur l'effet de la LCLL-ash calcinée à haute température (800°C et 1000°C) sur l'hydratation des pâtes de ciment est réalisée. La partie du ciment remplacée par la LCLL-ash calcinée est de 20% en masse et le e/c est de 0.485. La LCLL-ash calcinée a changé les produits d'hydratation avec la formation de la phase AFm-CO₃ et retarde la vitesse d'hydratation du ciment. Cependant, la chaleur générée par l'hydratation et la teneur en hydrates dans le ciment LCLL-ash calciné sont inférieures à celles du ciment LCLL-ash. On peut conclure que la calcination n'a pas amélioré de manière significative la réaction pouzzolanique du ciment LCLL-ash. Ceci est probablement lié à l'hétérogénéité de la LCLL-ash, entraînant un changement de sa composition chimique. Troisièmement, pour mieux comprendre l'effet des fillers minéraux sur les mélanges de BFUP, nous avons mené une campagne expérimentale large et complète au niveau de la pâte de ciment et du béton. Le ciment a été remplacé par des fillers minéraux issus de l'industrie de la pierre (poudre de granite, poudre de calcaire) et post-consommés (poudre de verre) qui sont disponibles localement au Québec. Les résultats obtenus permettent une meilleure compréhension de l'effet du remplacement du ciment Portland et de la fumée de silice par 10-40% de charges minérales sur les propriétés à l'état frais du béton, la cinétique d'hydratation, le retrait endogène et les propriétés mécaniques. L'effet du remplacement du liant par des fillers minéraux a également été vérifié à l'échelle du BFUP. Enfin, une formule LCLL-BFUP a été développée avec succès en optimisant la densité de compaction du mélange sur la base du modèle de compaction des particules (CIPM). La substitution du ciment parla LCLL-ash était de 6% et 12% de la masse. Les résultats montrent que la LCLL-ash retarde le pic d'hydratation maximum du clinker par rapport au mélange de référence. Cependant, la LCLL-ash aide à diminuer le retrait endogène, réduisant ainsi les fissures précoces. De plus, la substitution jusqu'à 12% de la masse du ciment par de la LCLL-ash est possible pour produire un BFUP répondant aux exigences de la norme canadienne (120 MPa). De plus, le mélange de BFUP développé a une teneur en ciment inférieure à 550 kg/m³, ce qui permet de réduire le coût et les émissions de CO₂ du BFUP.The high carbon emissions due to cement production is one of the most critical issues for fostering concrete sustainability. In the last decades, supplementary cementitious materials (SCMs) in concrete have become very common to produce sustainable concrete. Moreover, today, the growing worldwide demand for infrastructures is causing over-exploited natural material sources. Concerned by the limited availability of SCMs and their regional variation, there is today an urgent need for exploration of alternative SCMs which are locally available in the production of durable concrete. Every year 1.5 million tons of spent pot lining (SPL) are generated as waste from the primary aluminum smelters worldwide. After treatment, SPL becomes an inert material called LCLL-ash in this study. LCLL-ash is rich in aluminum and silica content which will be a potential property to replace cement in concrete. Firstly, ground LCLL-ash as the fineness of cement is replaced cement partially on the paste systems at 10 and 20% wt. A small amount of synthetic anhydrite (other by-products related to the aluminum industry) is also added in some mixes. As for normal concretes, the presented results show that LCLL-ash has a nucleation effect and low pozzolanic reaction at an early age, whereas LCLL-ash changes the hydration products with the presence of AFm-CO₃ and more ettringite compared to the neat paste. An optimized replacement level of 10% cement could be achieved without affecting the micromechanical properties. Secondly, a preliminary study on the effect of calcined LCLL-ash at high temperatures (800°C and 1000°C) on the hydration of cement pastes is carried out. The replacement cement by grind-(calcined) LCLL-ash is 20% wt. and w/b of 0.485. Calcined LCLL-ash has changed the hydration production with the formation of the AFm-CO₃ phase and delays the hydration of cement. However, the heat of hydration and the hydrates content in calcined LCLL-cement are lower than that of LCLL-cement. It can conclude that calcination did not significantly improve the pozzolanic reaction of LCLL-ash. This is possibly related to the heterogeneity of LCLL-ash, leading to changing its chemical composition. Thirdly, to better understand the effect of mineral fillers on UHPC mixtures, we carried out a wide and comprehensive experimental campaign at the cement paste and concrete scales. In particular, cement was replaced by mineral fillers from the stone industry (granite powder, limestone powder) and post-consumer (glass powder) which are locally available in Quebec. The presented results show a better understanding of the effect of replacing Portland cement and silica fume with 10-40% of mineral fillers on fresh concrete properties, hydration kinetics, autogenous shrinkage, and mechanical properties. The effect of replacing binders by mineral fillers was also verified at the UHPC scale. Finally, an LCLL-UHPC formulation was successfully developed by optimizing the packing density of the mixture based on the compaction-interaction packing model (CIPM). The substitution of cement by LCLL-ash was 6% and 12% wt. The result shows that LCLL-ash delays the maximum hydration peak of clinker compared to the reference mix. However, LCLL-ash helps decrease the autogenous shrinkage, reducing the early-age cracking. Moreover, the substitution of up to 12% wt. of cement by LCLL-ash is possible to produce UHPC to meet the requirement of Canadian standard UHPC (120 MPa). Furthermore, the developed UHPC mixture has a cement content of less than 550 kg/m³, resulting in lower cost and embodied CO₂ emission of UHPC

Simulating of Biofuel Production from Rice Husks

In the context of energy crisis and environmental damage due to rapid depletion and overuse of fossil fuel, alternative renewable energy resources such as biomass have been being significantly studied recently. In Southeast Asia countries like Malaysia, one of the abundant biomass feed stocks is rice husk which is a residue from rice production process. Rice husk can be transformed into gasoline through a series of fast pyrolysis and catalytic cracking processes. However, there is limited work on simulating the whole process. The objective of this project is to develop a mathematical simulation for the production of gasoline from rice husk using MATLAB. From the developed model, parametric studies have been conducted to identify the operating conditions which give the highest yield of product. The mathematic model was based on kinetic equations for the two main processes together with basic mass and energy balance for other subprocesses in the flowsheet. As a result, the model has shown that from 1000kg of rice husk, 191 liters of gasoline would be obtained. Within the studied range, the operating conditions at temperature of 783K and residence time of 5s for pyrolysis and at 723K in 1.25h for catalytic cracking are proposed to get the highest gasoline yield. The developed model can be considered as a basis for further research on simulating the production process of biofuel from rice husk

Digital Transformation of the Banking Industry in Developing Countries

Purpose:  The study's objective is to test the impact of digital transactions on banking performance. Based on the previous research and the actual situations, it has been recognized that the critical role of digital banking is in developing the banking industry, especially in developing countries.   Theoretical framework:  In the next section, the study presents background information to promote the research. The digital transformation has changed how customers use financial services. This has pushed banks to adapt more quickly to the wave of digital transformation if they don't want to lose their valuable customer base.   Design/methodology/approach:  the methodology applied uses POOL, FEM, REM, and FGLS models to examine the impact of banking transactions made by digital technology on the bank's deposit and lending revenue. This article studies banking operations on digital platforms from 2012 to 2019 in developing countries.   Findings: The article's findings showed that digital banks' flexible products and services bring many benefits with a high level of interaction, such as supporting the relationship between customers and banks and improving operating revenue.   Research, Practical & Social implications: Practical implications enhanced the development potential of digital banking is relatively large, stemming from the market demand development orientation of the banking industry.   Originality/value: The paper's originality and value help banks invest in digital technology as the way forward to better serve their customers

Factors Affecting the Bank Credit Accessibility of Rural Households in Vietnam

The research identifies and measures factors affecting the bank credit accessibility using Heckman (1979). The research uses data from dataset of Vietnam Household Living Standard Survey (VHLSS) in 2014 and 2016 to eliminate the shock due to the global economic crisis in 2008-2009 making the estimate unsustainable. The results show that among the factors that can affect the bank credit accessibility considered in the first stage of Heckman model, there are six factors that significantly and statistically affect the bank credit accessibility of rural households. These factors include the household’s average income, householder’s age, ethnic group, marital status, previous loan period and members of the Farmers Associations. The estimate results obtained from the second stage of Heckman model on the possibility to receive loans of rural households in Vietnam indicates seven factors affecting the value of loans received from bank credit institutions are the household’s average income, householder’s age, ethnic group, marital status, previous loan period and members of the Farmers Associations

USING RUBRIC TO ASSESS PRIMARY SCHOOL STUDENTS' COMPETENCE IN TEACHING SCIENCE IN VIETNAM

Vietnam is in the early stages of implementing the reform of the curriculum and textbooks. Vietnam's general education is changing strongly from content-based teaching to competence-building teaching [1]. That change has been implemented by researchers and teachers in all elements of the teaching process, including testing and evaluation. Evaluation of educational outcomes needs to shift from testing memorization to assessing the ability to apply knowledge to solve practical problems, attaching importance to both assessment of learning outcomes and assessment in the learning process. In this situation, testing and assessment in teaching Science in primary schools are also interesting to many teachers, and assessment of scientific competence in teaching this subject is considered an important factor contributing to improving the quality of Science and the quality of subject teaching in the direction of developing students' ability. The article mentions some theoretical foundations and the actual situation of using Rubric in assessing the scientific competence of students in grades 4 and 5 when teachers teach Science, thereby proposing some measures to improve the effectiveness of assessment in teaching this subject.  Article visualizations

MICROPLASTIC FIBER ACCUMULATION IN SOME WILD AND CULTURED SHRIMP SPECIES

This study was conducted to examine the microplastic fiber abundance and its characteristics in two wild and two cultured shrimp species collected at coastal areas in Hoai Nhon district, Binh Dinh Province. A total of 84 individuals of four shrimp species, Litopenaeus vannamei, Penaeus monodon, Metapenaeus ensis, and Penaeus semisulcatus were collected for analysis. All shrimp specimens were dissected to remove the digestive tracts, which were then treated with 10% KOH to collect microplastic fibers by filtering. The microplastic fiber concentrations varied from 1.96 ± 0.09 to 19.33 ± 10.82 fibers/specimen or 0.20 ± 0.12 to 2.26 ± 1.26 fibers/g of wet body weight. The abundance of fibers in the wild shrimps (Penaeus semisulcatus and Metapenaeus ensis) was higher than in the cultured shrimps (Penaeus monodon and Litopenaeus vannamei). Most fibers observed in the four shrimp species had lengths between 300 and 1500 μm, accounting for 78.72% to 92.82% of the total). White fibers were dominant (30.38%), followed by gray (11.87%), and green (10.60%)

VIETNAM?S COASTAL MANAGEMENT: GOVERNANCE, EFFECTIVENESS AND SUSTAINABILITY

Ph.DDOCTOR OF PHILOSOPH