115 research outputs found
Competing conventions: The Big Branders’ struggle to incorporate new quality conceptions in the Norwegian food market
Get PDFThe paper addresses recent changes in the Norwegian agrifood industry from the analytical perspective of quality conventions. Storper and Salais’ “worlds of production” plus Boltanski and Thévenots’ “orders of worth” are used as a basis for the empirical study. First, the paper discusses how the largest Norwegian branders try to strategically adapt to “novel” quality attributes like health-enhancing food, origin/terroir, environmental sustainability and ethics. Second, the paper investigates the companies’ quality signalling strategy: How are these “novel” qualities communicated to consumers? Multiple options are available: Do they attempt to systematically incorporate “novel qualities” into their private brand equity (“conventionalizing qualities”)? Do they prefer a co-labelling scheme with a third party control, or do they use any other measures for quality signalling? The paper thereby discusses how the largest Norwegian branders in the food sector cope with conflicting and competing quality conventions.Food quality, economics of convention., Food Consumption/Nutrition/Food Safety,
Analyzing the Influence of Water Depth on Total Resistance in Ulstein X-Bow Configuration: A Numerical Study
No full textConsidering resistance is a vital factor during ship design, especially when the vessel navigates through shallow waters. This situation leads to increased hull pressure as the ship advances. The ship can increase sinkage and trim, affecting the total drag of the vessel. It is important to predict resistance in water conditions with different surface heights accurately. This study aims to analyze the resistance at sea level. Testing the X-bow shape on the bow is predicted to affect the resistance analysis results. This study predicts ship resistance using the overset mesh technique in the Computational Fluid Dynamics method. According to the study's findings, utilising Ulstein X-Bow in deep water may reduce the total resistance value by 4.85%, followed by a change in sinkage angle by 2.32% and trim by 0.40%. Unfavourable outcomes are shown by the overall resistance value in moderate shallow water situations, and this happens as a result of the squat phenomenon, which is caused by a drop in pressure along the ship's bottom interacting with the water
Philipp E, Setchell M. Ginsburg J, eds. Scientific foundations of Obstetrics and Gynaecology. Fourth edition. 764 pages, tables, figures. Butterworth Hei‐nemann, Oxford: 1991
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Aspects of Flow and Heat Transfer in Finned Tube Bundles
Get PDFVarmeovergangseksperimentet ble gjennomført i en spesialisert rigg, hvor oppvarmet luft ble brukt som en erstatning for eksosgass. Både varmeovergang og trykkfall ble undersøkt for elliptiske rør med rektangulære finner, arrangert i forskjøvne rekker. Reynoldstallet ble beregnet ut fra det minste strømningsarealet og rørenes hydrauliske diameter, og varierte mellom 5 500 og 38 600. Gjennom en datareduksjonsprosedyre ble korrelasjoner for både trykkfall og varmeovergang funnet i form av henholdsvis Euler-Reynolds og Nusselt-Reynolds korrelasjoner.
Euler-Reynolds korrelasjonene var Eu = 13,910Re^-0,28 for den største blendeskiven, og Eu = 19,129Re^-0,31 for den minste blendeskiven. Disse korrelasjonene stemmer godt overens med tidligere publisert forskning, hvor Euler-Reynolds ligningene var innenfor spekteret av tidligere resultater. Nusselt-Reynolds korrelasjonene var Nu = 0,576Re^0,44 for den største blendeskiven, og Nu = 0,576Re^0,36 for den minste blendeskiven. Disse avviker fra tidligere resultater. Dette avviket ble antatt å være et resultat av begroing på innsiden av rørene, og denne begroingsfaktoren ble forsøkt tallfestet. Det viste seg at ved å legge til en begroingsfaktor på 0,0004-0,0007 m^2K/W så samsvarte resultatene med tidligere arbeid.
For å undersøke risikoen for ødeleggende rørvibrasjoner i kompakte varmevekslere, ble et Fortran 90 program laget. Programmet returnerer de naturlige svingefrekvensene og modusformene til et finnet rør med mellomliggende støtter. I tillegg blir risikoen for virvelindusert vibrasjon, fluidelastisk ustabilitet, turbulensindusert eksitasjon og akustisk resonans vurdert, basert på inngangsverdier som brukeren selv velger. For å teste programmet ble det kjørt med samme inngangsverdier som to tidligere eksempler fra litteraturen, og gjenskapte resultatene fra eksemplene godt.The heat transfer experiment was performed in a specialized rig, with hot air as a substitute for exhaust gas. Both heat transfer and pressure drop were investigated for a staggered tube array consisting of elliptical tubes with rectangular fins. The Reynolds number was based on the minimum flow area and the hydraulic diameter of the tubes, and was varied from 5 500 to 38 600. Through a data reduction procedure, correlations for both heat transfer and pressure drop were found in the form of Euler-Reynolds and Nusselt-Reynolds equations, respectively.
The Euler-Reynolds equations were Eu = 13.910Re^-0.28 for the large orifice and Eu = 19.129Re^-0.31 for the small orifice. These show a good agreement with published correlations, and the exponents are well within the range of previous work. The Nusselt-Reynolds equations were Nu = 0.576Re^0.44 for the large orifice and Nu = 0.576Re^0.36 for the small orifice. The Nusselt-Reynolds correlations show some deviation compared to previous work. This deviation was thought to be the result of fouling inside the tubes, and an attempt to quantify the fouling factor was made. Accounting for this fouling factor showed that a fouling factor of 0.0004 - 0.0007 m^2K/W would correlate the results nicely with previous work.
To investigate the risk of excessive tube vibration in compact heat exchanger units, a Fortran 90 program was created. The program returns the the natural frequencies and corresponding mode shapes of a finned tube with intermediate supports. In addition to this, it assesses the risk of vortex induced vibration, fluid-elastic instability, turbulent buffetting and acoustic resonance, based on input chosen by the user. To test the program, it was run with the same input as two previously worked examples from the literature, and managed to replicate the results well
Aspects of Flow and Heat Transfer in Finned Tube Bundles
No full textVarmeovergangseksperimentet ble gjennomført i en spesialisert rigg, hvor oppvarmet luft ble brukt som en erstatning for eksosgass. Både varmeovergang og trykkfall ble undersøkt for elliptiske rør med rektangulære finner, arrangert i forskjøvne rekker. Reynoldstallet ble beregnet ut fra det minste strømningsarealet og rørenes hydrauliske diameter, og varierte mellom 5 500 og 38 600. Gjennom en datareduksjonsprosedyre ble korrelasjoner for både trykkfall og varmeovergang funnet i form av henholdsvis Euler-Reynolds og Nusselt-Reynolds korrelasjoner.
Euler-Reynolds korrelasjonene var Eu = 13,910Re^-0,28 for den største blendeskiven, og Eu = 19,129Re^-0,31 for den minste blendeskiven. Disse korrelasjonene stemmer godt overens med tidligere publisert forskning, hvor Euler-Reynolds ligningene var innenfor spekteret av tidligere resultater. Nusselt-Reynolds korrelasjonene var Nu = 0,576Re^0,44 for den største blendeskiven, og Nu = 0,576Re^0,36 for den minste blendeskiven. Disse avviker fra tidligere resultater. Dette avviket ble antatt å være et resultat av begroing på innsiden av rørene, og denne begroingsfaktoren ble forsøkt tallfestet. Det viste seg at ved å legge til en begroingsfaktor på 0,0004-0,0007 m^2K/W så samsvarte resultatene med tidligere arbeid.
For å undersøke risikoen for ødeleggende rørvibrasjoner i kompakte varmevekslere, ble et Fortran 90 program laget. Programmet returnerer de naturlige svingefrekvensene og modusformene til et finnet rør med mellomliggende støtter. I tillegg blir risikoen for virvelindusert vibrasjon, fluidelastisk ustabilitet, turbulensindusert eksitasjon og akustisk resonans vurdert, basert på inngangsverdier som brukeren selv velger. For å teste programmet ble det kjørt med samme inngangsverdier som to tidligere eksempler fra litteraturen, og gjenskapte resultatene fra eksemplene godt
Beyond Jack-Ups: A Moonshot for Future Offshore Wind Turbine Installation Vessels for an Uncertain Market
No full textThe offshore wind market is rapidly growing, resulting in increasing wind turbine sizes, increasing distances to port, and a shift to deeper waters. A literature study in this thesis shows that existing wind turbine installation vessels, vessels under construction, and innovative concepts will not be able to install next-generation turbines or that they would have installation bottlenecks, making them cost-inefficient. This goes against the goal of decreasing the Levelized Cost of Energy (LCOE) of wind energy, to ensure that offshore wind stays competitive with other energy sources, enabling the energy transition. There is thus a gap between future demand of offshore wind installation vessels and current and near-term solutions. The research proposes a new floating monohull vessel concept, called Moonshot, to fill this gap. Moonshot will thus be different than traditional jack-up or semi-submersible installation vessel options.In this research, various design strategies were analyzed. Based on the findings, a design strategy is developed to design and analyze Moonshot. A combination of Ulstein Design and Solution B.V.’s Controlled Innovation process and Blended Design were used and extended to develop this new concept. First, the important functions and design aspects of the design were established using Controlled Innovation. Blended Design was then used to create a design space of the design configurations and to explore multiple market scenarios to establish optimal ship parameters for further development. As part of the research, the existing design process and model were modularized and new features were developed to suit wind turbines, assess seakeeping behavior, and explore the design space of the future wind turbine installation vessel.The results of this research aim to elucidate optimal design parameters across certain market scenarios. Results show how optimizing the design for financial performance, seakeeping behavior, or a combination of the two, influences the optimal design point. With the optimal design ranges, the initial design parameters for the next stage in the design of Moonshot are established. Finally, Blended Design is used to benchmark Moonshot against existing wind turbine installation solutions to assess its performance. A version of Moonshot is developed as a direct competitor for the largest jack-up design available, the NG-20000X. Benchmarking with the jack-up, an SSCV, and Huisman’s WIV concept showed that Moonshot would be a more efficient solution, capable of installing a larger number of turbines per year at a considerably lower cost per megawatt compared to the other solutions.In summary, this research concludes Moonshot as an innovative concept to address the evolving challenges of offshore wind turbine installation. By combining innovative design strategies, extensive assessment, and optimization, Moonshot emerges as a promising contender in the quest for effective and cost-efficient installation solutions for offshore wind.Marine Technology | Ship Desig
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