Investigating the Necessity of Standardized In-Situ Testing Procedures for One-Part Granite-based Geopolymers: An Experimental Study of the Influence of Loading Rate

Ordinary Portland cement (OPC) is the most popular choice for cementing material for petroleum well cementing. Since cement is used in the petroleum industry as an essential part of creating zonal isolation and ensuring well integrity during and after decommissioning. The drawback with using OPC is responsible for 8% of the worlds carbon dioxide emissions and to produce one tonne of OPC, emits 0.9 tonne of CO2. Hence the objective of this thesis to test if a rock geopolymer cement can be an alternative to OPC. Which have up to 80% less emission of CO2 compared to OPC. This thesis is one part of a three-part study of the properties to the rock based geopolymer Just add water (JAW-B). JAW-B is a granite-based rock-based polymer where all the activators are in the dry phase and only water is to be added to make the cement. The objective of thesis is to test the impact of different loading rates on the in-situ mechanical properties of the rock-based geopolymer JAW-B. A triaxial cell was used to simulate the downhole conditions and in-situ stress conditions of a petroleum wellbore. The test samples of JAW-B were prepared and cured for one week at 90°C at 2000 psi. A total of 18 JAW-B test samples were prepared and subjected to nine tests, each with duplicates, utilizing three different loading rates (0.5, 12, and 17.97+ MPa/min) and three distinct confining pressures (8, 17.2, and 26 MPa) Regarding Young's modulus, holding the piston load rate constant at 0.5 MPa/min and increasing the confining pressure from 8 MPa to 17.2 MPa resulted in a change in Young's modulus from a range of 0.71-0.73 GPa to 0.51-0.72 GPa. Further increasing the confining pressure from 17.2 MPa to 26 MPa led to an increase in Young's modulus to 1.01-1.09 GPa. Similarly, when holding the piston load rate constant at 12 MPa/min, increasing the confining pressure resulted in an increase in Young's modulus. A similar trend was observed for a piston load rate range of 17.97-23.3 MPa/min. Overall, increasing the confining pressure led to an increase in Young's modulus. Poisson's ratio was also examined in relation to confining pressure and piston loading rate. The results showed that increasing the confining pressure generally resulted in changes in Poisson's ratio, except for the case of a piston load rate of 0.5 MPa/min, where no noticeable change was observed. Increasing the piston loading rate generally led to an increase in Poisson's ratio, indicating that the samples became more ductile as the applied stress increased. The compressive strength of the samples was influenced by both confining pressure and piston loading rate. Increasing the confining pressure generally led to an increase in compressive strength, while the effect of piston loading rate was more variable and dependent on other factors. The bulk modulus of JAW-B was found to increase as the confining pressure increased from 8 to 26 MPa. This suggests that the material became less compressible and more resistant to changes in shape or volume under higher confining pressures. In conclusion, this study demonstrates that changes in both confining pressure and piston loading rate can significantly impact the mechanical properties of JAW-B. Based on the results of this thesis, it is recommended to conduct further testing on JAW-B geopolymer at low and high piston load rates under a confining pressure of 8 MPa. To qualify and establish a standard for JAW-B as an OPC substitute in well cementing, further testing against OPC benchmark properties is required. The obtained results are promising, but additional testing is necessary to ensure quality

Verdsettelse av Tesla Inc,

Bacheloroppgaven undersøker problemstillingen «hva er verdien til Tesla våren 2021?» ved å foreta en verdsettelse av Tesla Inc. Formålet til oppgaven er å undersøke Teslas fundamentale aspekter for å belyse hvilke forhold som førte til at selskapet økte betraktelig i verdi under Covid-19 i 2020. Oppgaven begynner først med å introdusere Tesla og hvilken verdsettelses metode jeg vil benytte. Deretter foretar jeg en strategisk analyse for å vurdere hvilke makroøkonomiske forhold påvirker Tesla, dette gjøres via en PESTEL- og Porter analyse, som til slutt oppsummeres i en SWOT analyse. Etter den strategiske analysen, vurderer jeg Teslas presentasjon de siste fem årene ved å sammenligne dens nøkkeltall med de andre topp automobilprodusentene i USA. Der finner jeg at Tesla har hatt dårlig presentasjon, men har hentet seg godt opp de siste tre årene. Videre foretas verdsettelsen av Tesla hvor selskapets fremtidige kontantstrømmer, avkastningskrav og terminalverdi estimeres. Estimatene benyttes til å estimere Teslas aksjepris. Aksjeprisen verdsettes til $361.38 per 23.04.2021, som avviker stort fra daværende kurs på$731.36. I sensitivitetsanalysen og konklusjonen så vurderer jeg mulige forhold som kan ha forårsaket avviket, til jeg avslutter oppgaven med å diskutere noen innvendinger.The thesis examines the research question "What is Teslas value the spring of 2021?" by conducting a valuation of Tesla Inc. The purpose of the thesis is to examine Tesla's fundamental aspects in order to shed light on factors that led to the company to significantly increase in value under Covid-19 in 2020. The assignment begins by first introducing Tesla and then which valuation method I will be using. Then I conduct a strategic analysis to consider which macroeconomic factors that may affect Tesla. This is done with both a PESTEL- and Porter analysis, which are summarized in a SWOT analysis. After the strategic analysis, I evaluate Tesla's performace over the last five years by comparing key figures with other top automobile manufacturers in the United States. There I find that Tesla had poor performance, but has recovered well in the last three years. Then the valuation is conducted, where the company's future cash flows, required rate of return and terminal value are estimated. The estimates are then used to estimate a stock price for Tesla. Lastly, the stock is valued at $361.38 as of 23.04.2021, which differs significantly from the then current price at$731.36. This difference I discuss in the sensitivity analysis and the conclusion, where I consider possible factors that may have caused the discrepancy. I end the thesis by considering its limitations

On the role of NOS1 ex1f-VNTR in ADHD – allelic, subgroup, and meta-analysis

Attention deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental disorder featuring complex genetics with common and rare variants contributing to disease risk. In a high proportion of cases, ADHD does not remit during adolescence but persists into adulthood. Several studies suggest that NOS1, encoding nitric oxide synthase I, producing the gaseous neurotransmitter NO, is a candidate gene for (adult) ADHD. We here extended our analysis by increasing the original sample, adding two further samples from Norway and Spain, and conducted subgroup and co-morbidity analysis. Our previous finding held true in the extended sample, and also meta-analysis demonstrated an association of NOS1 ex1fVNTR short alleles with adult ADHD (aADHD). Association was restricted to females, as was the case in the discovery sample. Subgroup analysis on the single allele level suggested that the repeat allele caused the association. Regarding subgroups, we found that NOS1 was associated with the hyperactive/impulsive ADHD subtype, but not to pure inattention. In terms of comorbidity, major depression, anxiety disorders, cluster C personality disorders and migraine were associated with short repeats, in particular the repeat allele. Also, short allele carriers had significantly lower IQ. Finally, we again demonstrated an influence of the repeat on gene expression in human post-mortem brain samples. These data validate the role of NOS-I in hyperactive/impulsive phenotypes and call for further studies into the neurobiological underpinnings of this association.PostprintPeer reviewe

European consensus statement on diagnosis and treatment of adult ADHD: The European Network Adult ADHD.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is among the most common psychiatric disorders of childhood that persists into adulthood in the majority of cases. The evidence on persistence poses several difficulties for adult psychiatry considering the lack of expertise for diagnostic assessment, limited treatment options and patient facilities across Europe. METHODS: The European Network Adult ADHD, founded in 2003, aims to increase awareness of this disorder and improve knowledge and patient care for adults with ADHD across Europe. This Consensus Statement is one of the actions taken by the European Network Adult ADHD in order to support the clinician with research evidence and clinical experience from 18 European countries in which ADHD in adults is recognised and treated. RESULTS: Besides information on the genetics and neurobiology of ADHD, three major questions are addressed in this statement: (1) What is the clinical picture of ADHD in adults? (2) How can ADHD in adults be properly diagnosed? (3) How should ADHD in adults be effectively treated? CONCLUSIONS: ADHD often presents as an impairing lifelong condition in adults, yet it is currently underdiagnosed and treated in many European countries, leading to ineffective treatment and higher costs of illness. Expertise in diagnostic assessment and treatment of ADHD in adults must increase in psychiatry. Instruments for screening and diagnosis of ADHD in adults are available and appropriate treatments exist, although more research is needed in this age group

The node of Ranvier in CNS pathology.

Healthy nodes of Ranvier are crucial for action potential propagation along myelinated axons, both in the central and in the peripheral nervous system. Surprisingly, the node of Ranvier has often been neglected when describing CNS disorders, with most pathologies classified simply as being due to neuronal defects in the grey matter or due to oligodendrocyte damage in the white matter. However, recent studies have highlighted changes that occur in pathological conditions at the node of Ranvier, and at the associated paranodal and juxtaparanodal regions where neurons and myelinating glial cells interact. Lengthening of the node of Ranvier, failure of the electrically resistive seal between the myelin and the axon at the paranode, and retraction of myelin to expose voltage-gated K(+) channels in the juxtaparanode, may contribute to altering the function of myelinated axons in a wide range of diseases, including stroke, spinal cord injury and multiple sclerosis. Here, we review the principles by which the node of Ranvier operates and its molecular structure, and thus explain how defects at the node and paranode contribute to neurological disorders

Bitcoin – a currency or an asset?

Cryptocurrencies is a part of the fast growing fintech market. Bitcoin is the first cryptocurrency, but also the currency with the largest market share. Bitcoin was created in 2009, by Satoshi Nakamoto, and have in the years since its release faced very volatile exchange rates. The purpose of Bitcoin is to create a currency that allows payments to be sent from one party to another without going through a financial institution. The volatile exchange rate, and Bitcoins attributes has raised the question of how to define Bitcoin. This thesis answers the research question: Bitcoin – a Currency or an Asset? The thesis defines what is fiat currency, monetary theory and monetary value, in addition to the asset classes capital assets, consumable/transferable asset and store of value assets. Bitcoin’s attributes are discussed in light of these definitions. Also included in the background are the governmental views on Bitcoin. Here the thesis focuses on how cryptocurrency is handled by legislators. In Japan cryptocurrencies are deemed legal tender, in the E.U. it is defined as currency, in the U.S. Bitcoin is defined as a commodity, while other cryptocurrencies is defined as securities, in China government has issued a ban on all cryptocurrency. The empirical part of this thesis is made up by time series regressions and rolling window regression using Bitcoin exchange rates, price of gold, OFRS financial stress index, S&P 500 and the federal funds rate as parameters. Bitcoin is designed to function as a currency, but lack of acceptance in the economy causes problems for the users. The volatile exchange rate also causes problems as it makes Bitcoin worthless as a measurement of value, and also difficult to use Bitcoin for consumption. Findings from the time series regressions and the rolling window regressions indicate that the Bitcoin’s exchange rate follows the asset market. When the S&P 500 increases and the OFR financial stress index is negative, indicating low stress in the financial market, the Bitcoin exchange rate increases. The exchange rate is also positively correlated with the price of gold. The empirical evidence, together with the theoretical framework leads to the conclusion that Bitcoin is an asset.nhhma

Financial crisis and the shipping industry : how and why shipping companies were affected by the crisis

The theoretical framework of this thesis includes macro arguments for trade, shipping theory and definitions, including Martin Stopford’s comprehensive shipping market model, and some theory and definitions on some of the financial terms, such as gearing, financial and operating lease, used in this thesis. The Baltic Dry Index (BDI) is a series of indices based on reports from independent and competitive shipbrokers. Its purpose is to provide the shippers and the ship-owners with unbiased information on freight rates, and it is thought to be one of the most accurate indicators of economic development in the shipping market. Due to environmental considerations, new IMO regulations state that by the end of 2010 all single-hulled tanker vessels should be phased out of the market and only double-hulled vessels will be accepted. This will result in more ships being scrapped or repurposed. The force behind the financial crisis was subprime mortgages sold to a higher rating than what they should have been, creating solvency and liquidity problems for the banks and the financial sector. It is reasonable to say the crisis started in the US, but it spread to other countries as well. The financial crisis led to a decline in world consumption, and thus world trade and the demand for shipping services decreased. The liquidity problems were faced by the shipping industry as well, with reduced attaining of debt due to interbank lending problems faced. Frontline is one of the world’s biggest tanker companies in the bulk trade. The Company has had a high debt to equity ratio during the period of 2004 to 2009 and the ratio peaked at 7.44 in 2007. The Company’s net income decreased from $701M in 2008 to$105M in 2009 due to the decrease in voyage and time charters. Revenues were down 46,1% from 2008 to 2009, which amounted to a staggering $971M. NAT operates in the tanker market and mainly transports crude oil. It is a fairly young company, which was founded in 1995, but has had a strong growth focus during its relatively short life. In contradiction to Frontline, NAT has a philosophy of low gearing and has financed their growth through issuance of common stock. Their debt to equity ratio was 0.2, 0.03 and 0.01 during the years of the financial crisis. Though, the net income of the Company plummeted from$119M in 2008 to $1M in 2009 due to low revenues and the cost of operating expense, including depreciation, amounting to$113M. Wilh. Wilhelmsen is the market leading company in RORO shipping. Due to the recent financial crisis the Company has had to put 17 vessels into layup entering 2010. The debt to equity ratio has been relatively low; 1.17 in 2004, 1.90 by the end of 2009 and peaking in 2008 at 2.56 due to the issuance of new debt. The freight revenues of Wilh. Wilhelmsen were nearly halved from 2008 ($293M) to 2009 ($153M) due to the sharp decline in average freight rates and the low utilization of the fleet. Odfjell is a worldwide provider of transportation and storage of bulk liquid chemicals, acids, edible oils and other special products. Odfjell’s extensive newbuilding program resulted in an increase in the company’s debt to equity ratio, which peak in 2008 at 2.59. The net result of the Company went from being negative in 2007 to a positive $110.5M in 2009 due to the repeal of the Norwegian tonnage tax system. Golden Ocean is a dry bulk shipping company focusing on Panamax, Kamsarmax and Capesize vessels. The Company has had a high debt to equity ratio during the years 2004-2009, 5.52 in 2007 and 4.74 in 2008, but in 2009 it was down to just 1.06 due to a major increase in equity and a decrease in debt. Further, the Company has had a return on capital employed peaking at 28.5020.79$350M, which was a dismal result compared to $877M the year before. Up until the crisis, the shipping industry saw a high degree of new-building, which created to large a supply of vessels during the decline and forced ships into layup. The various segments have all experienced a decrease in freight rates, but the chemical tanker market experienced the least volatile rates, which in turn hurt the companies as they have had a large portion of their ships in the spot market. Bunker cost increased freight rates and companies with hedges on bunker incurred substantial losses when the crude oil price plummeted. Chinese demand, especially for oil and iron ore, has been one of the main factors driving the increased and decreased demand for vessels, both prior to and during the financial crisis. All the shipping companies analyzed, but NAT, have experienced prevailing low share prices when comparing towards the BDI, BDTI, BCTI, OSEBX and the NYSE. The NYSE and OSEBX did not incur as high a decline as the shipping companies, making us believe the shipping industry was one of the losers in the midst and end of the financial crisis