En studie av den gassdrevne forbrenningsmotoren og dens potensiale

Denne masteroppgaven er skrevet som en avsluttende del av sivilingeniørstudiet Maskin- prosess- og produktutvikling ved Fakultet for Realfag og Teknologi (REALTEK) hos Norges Miljø- og Biovitenskapelige Universitet (NMBU). Fakultetet ønsket å øke sin kunnskap om forbrenningsmotorer og unike systemer i kjøretøy som går på biogass og valgte derfor å initiere denne masteroppgaven i vårsemesteret 2023. Rapportens mål er å samle detaljert informasjon om gassmotorer som opererer på biogass, da dette fremstår som en spennende miljøvennlig teknologi med interessant potensiale. Dette er gjort ved hjelp av litteratursøk og innhenting av informasjon fra ressurspersoner. Det har pågått et fast samarbeid med ressurspersoner hos Norsk Scania AS. For at man skal få et godt utbytte av rapporten forutsettes det at leseren har en teknisk eller ingeniørfaglig bakgrunn. Rapporten gjennomgår kort de prosesser som er aktuelle for produksjon av biogass. Den tar også for seg det norske potensialet for produksjon av biogass, og hvilke energimengder som kan hentes ut dersom det er vilje og forutsetninger for det. Videre gis det teorigrunnlag som er relevant for forståelsen av gass-relaterte motor- og kjøretøysystemer. Til slutt er det utført en studie av en 13-liter gassdrevet ottomotor fra Scania, med tilhørende gassystem. Studiet gir en detaljert gjennomgang av gasstankene som benyttes til å lagre både flytende og komprimert gass i kjøretøyet, samt motoren og dens komponenter, systemer og virkemåte. Det er et lovende potensiale for biogassproduksjon i Norge. Det kan potensielt, dersom det er vilje til det, produseres 11,3 TWh årlig i fremtiden. Teknologien for gassdrevne kjøretøy fremstår som moden og godt egnet for tungtransport. Den gassdrevne forbrenningsmotoren har vært kjent siden før første verdenskrig, noe som har gitt god tid til utvikling av forbrenningsteknologien. Motoren fra Scania har elektronisk styrt tenning som regulerer forbrenningen i hvert stempel individuelt, EGR og et effektivt gassystem som regulerer gasstrykk- og forsyning løpende etter motorens behov. Utfordringene ligger i begrenset rekkevidde forbundet med lagring av gassen i kjøretøyet. Biogass tar henholdsvis 1,7 til 5 ganger større plass enn diesel, avhengig av om gassen er flytende eller komprimert. Flytende gass må også holdes under -161,4 ℃, noe som byr på problemer dersom kjøretøyet står ubrukt over tid. Ved bruk av kjøretøy fra Scania har komprimert gass i dag en maksimal rekkevidde på ca. 664 km per fylling, mens flytende gass har en maksimal rekkevidde på 1597 km per fylling. Det er også foreløpig knyttet utfordringer til nettverket av fyllestasjoner, da det inntil videre ikke finnes fyllestasjoner nord for Trondheim. Dette ventes løst for flytende gass innen 2026. Av litteratur som har vært nyttig for utarbeidelsen av rapporten, anbefales følgende bøker: - Natural Gas and Renewable Methane for Powertrains av Richard Van Basshuysen. - Motorteknikk av Leif Lundby m.fl.This master's thesis has been written as the final part of the civil engineering study Machine- Processand Product Development under the Faculty of Science and Technology (REALTEK) at the Norwegian University of Life Sciences (NMBU). The faculty wanted to increase their knowledge of internal combustion engines and the unique systems associated with vehicles that run on biogas. For this reason, they chose to initiate this master's thesis in the spring semester 2023. The aim of the report is to gather detailed information about gas engines that operate on biogas, as this appears to be an exciting, environmentally friendly technology with interesting potential. This has been done using standard literature search and by obtaining information from resource personnel. There has been ongoing collaboration with personnel at Norsk Scania AS. To get the most out of the report, the reader should have a technical or engineering background. The report briefly reviews the processes that are relevant for the production of biogas. It also considers the Norwegian potential for biogas production, and the amounts of energy that can be extracted, as long as there is a will and the conditions for it are met. Further, the report supplies the theoretical basic knowledge needed for the understanding of gas-related engine- and vehicle systems. As the final part of the report, a study has been done on a 13-litre gas-powered otto engine from Scania, along with its associated gas system. The study provides a detailed review of the gas tanks used to store both liquid and compressed gas in the vehicle, as well as the engine and its components, systems, and operation. There is a promising potential for biogas production in Norway. Potentially, if there is a will to do so, 11.3 TWh can be produced annually in the future. The technology used in gas-powered vehicles appears mature and well suited for heavy transport. The gas-powered combustion engine has been known since before the First World War, which has given plenty of time for the development of the combustion technology. The engine supplied by Scania has electronically controlled ignition that regulates combustion individually for each combustion chamber, EGR and an efficient gas system that regulates gas pressure and supply continuously, according to the needs of the engine. The challenge is located in the limited range, due to challenges associated with gas storage within the vehicle. Biogas requires 1.7 to 5 times the volume of diesel, depending on whether the gas is liquid or compressed. Liquefied gas must also be kept below -161.4 ℃, which can be problematic if the vehicle is left unused for longer periods of time. When using vehicles from Scania, compressed gas has a maximum range of approx. 664 km per full tank, while liquid gas has a maximum range of 1597 km on a full tank. There are also challenges with regards to the filling station network, as there are currently no filling stations north of Trondheim. For liquefied gas, this is expected to be resolved by 2026. Regarding literature that has been useful for the creation of the report, the following books can be recommended: - Natural Gas and Renewable Methane for Powertrains by Richard Van Basshuysen. - Motorteknikk by Leif Lundby et.al

Etablering av kjøpesentra i tidlig fase

SUMMARY II This master-report examines the establishment of shopping centers in the early stages. The main issues that must be clarified in order to establish a shopping are described. It addressed a focus on the legal provisions and economic considerations that must be used. The master-report gives an introduction of a theoretical part with relevant law, and historical development of shopping centers. Market conditions, both nationally and locally in Vestfold are described. This is meant to give the reader the necessary background to understand how an establishment can take place and further understand the process around the establishment of a shopping center. Central and professionals working with shopping center-development are interviewed and information from these are summarized and adjusted for further understanding of what is important when establishing. Local politicians working on the committee for construction and land use issues and city council in Tønsberg are interviewed to get an insight into how they consider this type of establishment. To provide a practical approach, a shopping center project in the early phase at Kilen Tønsberg is included as an example of a real establishment. There has been extensive analysis work that is summarized in an economic calculation. What the professionals working with shopping center-development emphasize when establishing: location, develop new shopping centers downtown and near intersections. Good infrastructure with good traffic flow is important. It is important to establish more centers and be number 1 or 2 in their region. Good retail mix. Projects with development opportunity are positive. The participants emphasize the environment and have already set in motion series of measures to reduce energy use. Local politicians from Tønsberg emphasize what a shopping center can give back to the city in terms of positive effects. New jobs, effects that improve the city and better logistics that leads to reduced carbondyoxide pollution are some of the elements. Further, there is a focus that the establishment does not come into direct conflict with the shops downtown and loss of their business. According to my calculations the conclusion for the Kilen project is that it is economically feasible

Distribution, Size, and Shape of Abdominal Aortic Calcified Deposits and Their Relationship to Mortality in Postmenopausal Women

Abdominal aortic calcifications (AACs) correlate strongly with coronary artery calcifications and can be predictors of cardiovascular mortality. We investigated whether size, shape, and distribution of AACs are related to mortality and how such prognostic markers perform compared to the state-of-the-art AC24 marker introduced by Kauppila. Methods. For 308 postmenopausal women, we quantified the number of AAC and the percentage of the abdominal aorta that the lesions occupied in terms of their area, simulated plaque area, thickness, wall coverage, and length. We analysed inter-/intraobserver reproducibility and predictive ability of mortality after 8-9 years via Cox regression leading to hazard ratios (HRs). Results. The coefficient of variation was below 25% for all markers. The strongest individual predictors were the number of calcifications (HR = 2.4) and the simulated area percentage (HR = 2.96) of a calcified plaque, and, unlike AC24 (HR = 1.66), they allowed mortality prediction also after adjusting for traditional risk factors. In a combined Cox regression model, the strongest complementary predictors were the number of calcifications (HR = 2.76) and the area percentage (HR = −3.84). Conclusion. Morphometric markers of AAC quantified from radiographs may be a useful tool for screening and monitoring risk of CVD mortality

Energy expenditure, dietary intake and energy availability in female professional football players

Objectives: To quantify energy expenditure and intake in professional female footballers playing on a national and/or international level. Second, to determine the prevalence of low energy availability among these players, defined as <30 kcal/kg fat-free mass (FFM)/day. Methods: Fifty-one players completed a 14-day prospective observational study during the 2021/2022 football season. Energy expenditure was determined using the doubly labelled water method. Energy intake was assessed using dietary recalls, while global positioning system determined the external physiological load. Descriptive statistics, stratification and the correlation between explainable variables and outcomes were conducted to quantify the energetic demands. Results: The mean energy expenditure for all players (22±4 years) was 2918±322 kcal. Mean energy intake was 2274±450 kcal, resulting in a discrepancy of ~22%. Carbohydrate intake was below the recommended guidelines on match day at 4.5±1.9 g/kg. The mean energy availability was 36.7±17.7 kcal/kg FFM/day on matchday and 37.9±11.7 kcal/kg FFM/day on training days, resulting in a prevalence of 36% and 23% for low energy availability during the observational period, respectively. Conclusion: These elite female football players displayed moderate energy expenditure levels and failed to meet the recommended levels of carbohydrate intake. In conjunction with inadequate nutritional periodisation, this will likely hamper performance through inadequate muscle glycogen resynthesis. In addition, we found a considerable prevalence of low energy availability on match and training days

Evaluating the suitability of the Low Energy Availability in Females Questionnaire (LEAF-Q) for female footballers

Background - The Low Energy Availability in Females Questionnaire (LEAF-Q) is a screening tool developed to detect endurance athletes and dancers at risk for development of persistent low energy availability (LEA) and the female athlete triad (Triad). This study investigated the applicability of the LEAF-Q in a cohort of sixty professional female football players. Methods - The participants were classified as at risk (≥ 8) or not at risk ( Results - Thirty-two percent of participants were classified as at risk by the LEAF-Q. We found no statistically significant differences between the two groups for any markers associated with persistent LEA. Except for acceptable accuracy in determining menstrual status, all other LEAF-Q components exhibited poor accuracy and predictive values. Youden’s index scores imply that increasing the overall and injury cut-off values to ≥ 10 and ≥ 5 respectively, would yield increased performance. Conclusions - Our findings do not support the use of the LEAF-Q for the purpose of detecting LEA and Triad conditions among female football players

Study protocol: Prevalence of low energy availability and its relation to health and performance among female football players

Enduring low energy availability (LEA) is associated with several potentially serious physiological and mental conditions. LEA has been found highly prevalent among female elite athletes within endurance sports, thus hampering athletes’ health and performance. The prevalence and the underpinning risk factors of LEA among female elite football players are less studied. One reason is that the existing self-report measures and technological devices to monitor energy intake and expenditure are inadequately adapted to capture the nature of the physical activity and energy expenditure among football players and are thus inaccurate. The present paper outlines a study protocol addressing the prevalence of LEA, the measurement of LEA and the correlations of LEA in terms of health and performance in female football players. Four studies will be conducted with the following aims (1) to evaluate the accuracy of global positioning systems (GPS)-based devices to monitor energy expenditure with indirect calorimetry as the gold standard, (2) to assess energy intake, quantify energy expenditure and investigate energy availability through self-report instruments, double labelled water (DLW) and GPS monitoring devices, (3) to determine the point prevalence of LEA using self-report instruments, DLW, dual-X-ray-absorptiometry (DXA) to quantify muscle and bone mass distribution and density, and a battery of hormonal analyses, and (4) to explore whether the prevalence of LEA varies across a full football season. Measures covering mental symptoms and psychological resources will be included, and a selection of biological measures derived from study 3. Measurements of DXA and DLW are resource-demanding and will be collected from one professional club (N~20 women). In contrast, the remaining data will be collected from four professional clubs (N~60 women) located in Bergen, the largest city within the Western region of Norway. Overall procedures and biobank storage procedures have been approved for data collection that will end in December 2024.publishedVersio

A study of the side effects of Pandemrix influenza (H1N1) vaccine after whole-crew vaccination on board a Norwegian naval vessel

Background: The frigate His Norwegian Majesty’s ship (HNoMS) Fridtjof Nansen was participating in operations in the Gulf of Aden in support of the EU mission tasked with protecting vessels from the threat of piracy. The crew was therefore prioritized and given the first batch of Influenza A (H1N1) vaccine (Pandemrix®). Objectives: To investigate the type, frequency, and intensity of side effects after whole-crew vaccination with Pandemrix vaccine in healthy subjects in a controlled environment. Material and methods. A hundred and thirty-three members of the crew were vaccinated, and then they participated in the study. The side effects of the vaccination were evaluated through a survey. Results: Seventy-five per cent of the vaccinated sailors reported adverse reactions to the vaccine, with 9% not being able to perform their daily duties for one day. Muscle pain, headaches, malaise, and fatigue were the most frequent symptoms reported. Conclusions: The vaccination program using Pandemrix H1N1 vaccine resulted in a high rate of side effects, which were generally mild and resolved within a few days. No serious lasting side effects of the vaccination were reported or registered. The adverse effects of the vaccination did not affect the operational capacity of the vessel.publishedVersio

Kalveklassifisering og kalveslaktetilskudd for reinkalv

Klassifiseringssystemet EUROP ble innført for slakterein i 2015. Dette skulle stimulere reineierne til å levere slaktedyr med god kjøttfylde og med økt inntjening av den enkelte rein. Effektene av kalveslaktetilskuddet er vurdert, hvordan klassifiseringssystemet for kalv har fungert, og om kalveslaktetilskuddet bør knyttes til klassifiseringssystemet. Konklusjoner er: • Kalveslaktetilskuddet har fungert hensiktsmessig, men behovet er i dag endret • Tilskudd kan knyttes til kvalitet og motivere for langsiktig kvalitetsforbedring • Reindriftsfaglig grunnlag, forankring og tillit bør vektlegge

Physical performance and loading for six playing positions in elite female football: full‐game, end‐game, and peak periods

The present study investigated the position-specific match demands and heart rate response of female elite footballers, with special focus on the full-game, end-game, and peak-intensity periods. In total, 217 match observations were performed in 94 players from all eight teams of the best Danish Women's League, that is, goalkeepers (GK, n = 10), central defenders (CD, n = 23), full-backs (FB, n = 18), central midfielders (CM, n = 28), external midfielders (EM, n = 18), and forwards (FW, n = 11). Positional data (GPS; 10 Hz Polar Team Pro) and HR responses were collected. HRmean and HRpeak were 87%-89% and 98%-99% of HRmax, for outfield players, with no positional differences. CM, EM, and FB covered 8%-14% greater (P < .001) match distances than CD. EM, FW, FB, and CM performed 40%-64% more (P < .05) high-speed running and 41%-95% more (P < .01) very-high-speed running (VHSR) than CD. From the first to the last 15-minute period, total distance, except for FW, number of VHSR, except FB, peak speed and sum of accelerations and sum of decelerations decreased (P < .05) for all outfield positions. In the most intense 5-minute period, EM, FB, and CM performed 25%-34% more (P < .01) HSR than CD, whereas EM, FW, and FB performed 36%-49% more (P < .01) VHSR than CD. In conclusion, competitive elite female matches impose high physical demands on all outfield playing positions, with high aerobic loading throughout matches and marked declines in high-speed running and intense accelerations and decelerations toward the end of games. Overall physical match demands are much lower for central defenders than for the other outfield playing positions, albeit this difference is minimized in peak-intensity periods

The prevalence and clinical relevance of hyperhomocysteinemia suggesting vitamin B12 deficiency in presumed healthy infants

Background Previous studies have demonstrated a high prevalence of biochemical vitamin B12 deficiency in infants in Norway. Increased total homocysteine (tHcy) is the most important marker of B12 deficiency in infants. There is a need to evaluate its clinical relevance. Aims To investigate the prevalence of hyperhomocysteinemia (S-tHcy > 8 μmol/L) suggestive of suboptimal B12 status and the prevalence of clinically relevant hyperhomocysteinemia in presumed healthy infants in Norway. Further, to evaluate risk factors, presence of symptoms and psychomotor development in these children. Methods In a prospective study we clinically examined 252 infants aged 3–7 months using standardized neurological and psychomotor tests prior to analyzing biochemical B12 deficiency markers in 250 infants. Results Twenty-five of 250 (10%) infants had hyperhomocysteinemia combined with clinically relevant symptoms suggestive of B12 deficiency. Hyperhomocysteinemia was associated with tremor, excessive sleep, and sub-normal scores in the fine motor section of the Ages and Stages Questionnaire. One-hundred and fourteen of 250 (46%) infants had hyperhomocysteinemia. Multiple regression analysis showed months of infant formula use as the strongest negative predictor for hyperhomocysteinemia. Conclusion We have demonstrated associations between symptoms suggestive of infant B12 deficiency and increased levels of tHcy in presumed healthy infants The combination of hyperhomocysteinemia and associated relevant symptoms suggestive of B12 deficiency was a common finding, albeit most infants with hyperhomocysteinemia did not show symptoms.publishedVersio