Transient flow analysis of opening hinged/sliding door

Most people spend the majority of a day indoors where temperature and air quality have a big impact on their work performance, comfort and health. To be able to control the spread of diseases in indoor environments it is crucial to understand the indoor air flows. An important part of this is to look at the different factors which effects the way the air moves. Understanding of air flow and mass exchange by the opening of a door is beneficial for estimation of pollutant transport and this makes us able to better predict and control desired indoor environment. In this thesis Numerical simulations were performed to solve coupled of mass, momentum and energy transport equations. The focus of this work was the usage of the overset mesh for moving rigid boundaries and two-equation turbulence models towards understanding the effects of door opening speed and time, thermal effects, and turbulence models. This work is also very relevant to the present pandemic situation. The simulations involve three different types of doors. One hinged, one sliding and one elevator door. In addition to the different door types, it has also been performed simulations with different opening times and thermal effect. Besides how the door moves the geometry and boundary conditions are the same for each case. To track the air exchange between the two rooms sulfur hexafluoride (SF6) tracer gas was used. To verify the CFD methods used in the thesis a test case that is similar in both physics and geometry to the simulations previously reported by the other researchers in the literature have been reproduced. When reviewing the flow field and the velocity It is evident from the comparison that the solutions from the reproduced model agree well with the literature. The comparison of the opening and closing door motions times for the hinged and the sliding door shows that the total time of the motion affects the airflow. Lower opening time creates a higher velocity and more exchange between the two rooms. For the non-thermal simulations visual comparison was done by monitoring the mass fraction of SF6 in a scalar scene and the velocity with the use of the Line Integral Convolution (LIC) in the vector scene. The results clearly shows that the hinged door creates most exchange of air and creates the most velocity in the airflow. The sliding door and the elevator door has less effect. The cumulative mass of SF6 exchanged through the door opening was also monitored and showed that the hinged door has the biggest impact. Time snaps at different timesteps of velocity and mass flux shows the same trend with the biggest effect from the hinged door. For the thermal cases is also shown that the hinged door creates most exchange of air and creates the most velocity in the airflow. Still the sliding door and the elevator door seems to be most affected by the temperature. Meaning that these cases show a clearer difference compared to the non- thermal case. The cumulative mass of SF6 exchanged through the door opening is also closer to hinged door. The time snaps at different timesteps shows the same trend with the most change in velocity and mass flux for the elevator and the sliding door. The hinged door is also seen the dominant force for the thermal case but it is seen clearly that the temperature difference effects the airflow. It can be concluded that STAR CMM+ is a powerful tool and that the overset mesh works well for the purpose of simulating solid movements. Using the overset mesh is a demanding process in the start-up phase, but this type of CFD simulations provide valuable information for estimation of pollutant transport and prediction of desired indoor environment. The results are also relevant for energy use, the thermal simulations of the cold storage room in particular.publishedVersio

Smart thermal grid concepts for the Leangen area

Sammendrag Leangen består for øyeblikket av en veddeløpsbane. Koteng Eiendom AS planlegger å rive banen, for å deretter bygge et bærekraftig boligområde med lavt energiforbruk og klimavennlig fotavtrykk. Byggeplanene inkluderer boliger og næringsvirksomhet, i tillegg til helse- og velferdstjenester som barnehage og vernede boliger. Veddeløpsbanen ligger ved siden av et idrettsanlegg, som blant annet består av flere isbaner. For å holde isbanene kalde er det installert en ammoniakkvarmepumpe. Informasjon fra kontaktpersoner ved dette anlegget viser at anlegget produserte 4 152 116 kWh med spillvarme i 2018. Dette betyr at det ligger en uutnyttet varmekilde med stort potensial i nærheten av Leangen. En mulighet for å dekke Leangens fremtidige varmebehov er derfor å bruke denne overskuddsvarmen som varmekilde, sammen med et lokalt lavtemperaturenerginett. Intensjonen med oppgaven er å utforske nettopp denne muligheten Ettersom bygningsplanene enda ikke er fastsatt, er det valgt å designe en fiktiv bygning som skal representere den gjennomsnittlige boligblokken på Leangen. Energibehovet for denne bygningen er en kombinasjon av varme- og varmtvannsbehovet fra en passivhusbygning i Trondheim og simulerte kjølebehov fra SIMIEN. For å best mulig dekke bygningens varmebehov ved bruk av skøytebanenes spillvarme, er det utviklet er energidistribusjonssystem. Systemet fokuserer på å bruke varmtvannet fra lavtemperaturnettet, både i et vannbårent gulvvarmesystem og som varmekilde for en varmtvannsvarmepumpe. Gulvvarmen skal dekke alt av romoppvarming og en 2 varmepumpe skal dekke varmtvannsbehovet. Den representative bygningen har i tillegg et betydelig kjølebehov. Det er derfor installert et vannbårent taksystem som absorberer den overflødige varmen i bygget. Dette er koblet til varmepumpen som ekstra varmekilde for varmtvannsoppvarming. Resultatene viser at spillvarmen fra skøyteanlegget ikke vil være nok til å dekke Leangens varmebehov. Bygningens energidistribusjonssystem ble derfor justert til å kunne inkludere energigjenvinning fra gråvann. Innledningsvis ble det sett på mulighetene for å samle gråvannet fra den individuelle bygningen, og deretter koble gråvannstanken til varmepumpen som en ekstern kilde for varmtvannsoppvarming. Dette førte til en betydelig reduksjon i behovet for spillvarme fra skøyteanlegget. Reduksjonen var imidlertid ikke nok til å kunne dekke det totale varmebehovet. På bakgrunn av dette ble det sett på mulighetene for å samle den totale gråvannsmengden fra boligområdet. Ved å samle dette i et sentralt basseng/tank og så koble det til lavtemperaturnettet via en varmepumpe, ble det totale behovet for spillvarme nok til å dekke det årlige vamebehovet. Selv om denne løsningen dekket det årlige behovet totalt, var varmebehovet i januar fortsatt større enn den tilgjengelige spillvarmen. En mulig løsning er å koble lavtemperaturnettet til fjernvarmenettet. Dette medfører at fjernvarme kan importeres når spillvarmen ikke strekker til. På tross av at varmebehovet i januar er for stort til å kunne dekkes av den tilgjengelige spillvarmen, vil det resten av året være et stort overskudd av spillvarme, inkludert desember. Dette muliggjør en eventuell lagring av overskuddvarme i et termisk lager for senere bruk. Dersom overskuddsenergien i desember kan lagres for senere bruk, er det mulig å bruke desembers overskudd til å dekke mangelen på spillvarme i januar.Abstract At the present, Leangen is occupied by a race course. Koteng Eiendom AS are going to demolish it and build a sustainable community with a low environmental footprint in its stead. The construction plans for this area include housing and businesses, in addition to public services such as a kindergarten and a health and welfare center. Next to the racecourse is a sports facility containing several ice rinks. To keep the rinks cold, the facility has installed a large ammonia heat pump. Information provided by a contact person at the facility shows that the heat pump system produced a total of 4 152 116 kWh of waste heat in 2018. The excess heat was released into the ambient air through dry coolers on the roof. This means that there is a local source of untapped heat nearby ready to be exploited. A possible way of covering Leangens future residential heating demand can therefore be to use the skating rinks as a heat source in combination with a low temperature thermal grid. The objective of this assignment is to explore this very option. Given that the construction plans are not yet definitive, it was decided to design a fictive building representing the average residential building at Leangen. The buildings demands are a combination of the hot water- and space heating demands from another passive house building in Trondheim. The cooling demands are a result of simulations in SIMIEN. To cover the demands by way of the Sports facility’s waste heat, an energy distribution system for the representative building was designed. The system focuses on applying hot water from the low temperature thermal grid as the source for both a waterborne floor heating system and as the heat source for hot water heating. The floor heating system is set to fully cover the space heating demands, while a CO2 heat pump covers the hot water demands. The representative building also has a considerable need for cooling. The distribution system covers the cooling demand by way of a waterborne ceiling system. This is connected to the heat pump as an extra heat source for hot water heating. The results showed that it is not possible to cover Leangens heating demands by using the waste heat from the skating rinks alone. It was therefore decided to adjust the energy distribution system, making it able to include heat recovery from greywater as well. Initially, greywater from each building was accumulated in greywater tanks connected to the hot water heat pump as an additional heat source. This reduced each buildings energy consumption from the low temperature thermal grid. Even so, this reduction was not enough for the sports facility’s waste heat to suffice. Subsequently, the accumulation of the entire residential area’s greywater production was explored. It was discovered that by accumulating this in a centralized pool and connecting it to the LTTG with a heat pump, the greywater potential increased tremendously. When the greywater energy was directly imported into the LTTG the total annual available waste heat was enough to cover the annual waste heat consumption. However, the waste heat consumption in January still exceeded the available waste heat. A proposed solution was to connect the LTTG to district heating. The district heating could thus be an emergency heat source for when the system is at a lack of waste heat. Even though the consumption in January exceeded the available waste heat, there was a considerable excess of waste heat the rest of the year. This includes December. If the excess energy in December can be stored for later use, this can cover the expected deficit in January

Are Dividend Arbitrage Strategies Present in Asia? An empirical study on cum-cum and cum-ex transactions in Asian markets

This thesis investigates whether dividend arbitrage strategies are present in Asian markets. The term refers to trading schemes where investors collude to exploit loopholes related to dividend withholding taxes. We focus on two variations of these strategies, known as cum-cum and cum-ex transactions, which have caused substantial tax losses in Europe. Our sample consists of the ten largest stock exchanges in Asia, spread across a total of nine countries. We conduct a review of dividend taxation in these countries and determine that the tax laws in four of them provide incentives for investors to engage in dividend arbitrage strategies. We use an event study methodology to analyse whether abnormalities in share turnover and short sales occur around ex-dividend dates for the 25 largest companies on each stock exchange during the period from 2012 to 2022. Our findings indicate that dividend arbitrage strategies are mostly absent in Asian markets. However, we find indications that they may be present in Taiwan and Japan. For Taiwan, we find that share turnover increases by 48% immediately before the ex-dividend date. Similarly, we find that short selling in Japan increases by 72.5%, but the evidence is inconsistent on a yearly basis. In contrast to that of Europe, it appears that legislations in most Asian countries are effective in preventing exploitation of dividend withholding taxes. Nonetheless, our findings suggest that Taiwan and Japan might be an exception.nhhma

The Role of Information Asymmetry in Private Placements - Evidence from Norway

Masteroppgave(MSc) in Master of Science in Business, Finance - Handelshøyskolen BI, 2021This thesis examines private placements on the Oslo Stock Ex- change. We study the issuing rm's announcement statements, post-issue rm performance, and the market reaction to disclose the role of asymmetric information in private placements. We nd that the market reacts more favorably to rms that reveal speci c information about their intended use of proceeds. However, we do not nd evidence indicating that speci c rms are more likely to engage in value-maximizing projects than rms that are vague. Previous literature has explained an adverse market reaction to SEOs using the agency theory, market timing, and the pecking or- der theory. We do not nd convincing support for either theory. Thus, our ndings indicate a market ine ciency left unanswered for future research

The Emotional Neglect in Recent Service Design Developments

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Investigating trust relationships between software development teams and information security stakeholders

Smidig utvikling har de siste tiårene fått stor oppmerksomhet i IT-industrien og forskningsmiljøet. Utviklingsmetodikken har introdusert mange fordeler for programvareleveranse, blant annet et større fokus på tverrfaglig samarbeid samt raske og hyppige leveranser. Men smidig utvikling har også ført til bekymringer knyttet til sikkerheten til IT-systemene og programvaren utviklet med metodikken. Sikkerhetspersonell rapporterer om at de ikke klarer å holde følge med det høye utviklingstempoet til smidig utvikling. De rapporterer også om problemer med samarbeid mellom ansatte i sikkerhetsroller og utviklere. Smidig utvikling er en metode som baserer seg mye på menneskelige faktorer og samarbeid, og det trengs mer forskning på dette feltet for å løse samarbeidsproblematikken. Tillit i team har vist seg å ha positive konsekvenser for samarbeid og effektivitet. Denne studien undersøker tillitsrelasjoner mellom utviklerteam og sikkerhetsaktører rundt teamet og hvordan tillitsrelasjonene påvirker arbeidet med informasjonssikkerhet i teamene. For å undersøke dette, har vi gjennomført en multiple-case studie med semi-strukturerte intervjuer. Våre funn indikerer at tillitsrelasjoner mellom utviklerteam og sikkerhetsaktører påvirker arbeidsprosessen med informasjonssikkerhet. Utfordringene relatert til troverdighetsfaktorer ble stort sett funnet i én retning av forholdet: når utviklerteamet er den som skal stole på sikkerhetsaktøren. Vi har funnet utfordringer relatert til fire troverdighetsfaktorer; evne, forutsigbarhet, transparens og velvilje. Funn om konsekvenser viser at det var mest prosessrelaterte konsekvenser; utviklere tar snarveier, ineffektiv kommunikasjon mellom aktørene og mangel på motivasjon for å engasjere seg i informasjonssikkerhetsarbeid. Til slutt, foreslår vi anbefalinger for å bygge tillit mellom utviklerteamet og sikkerhetsaktøren for å bedre arbeidet med informasjonssikkerhet i utviklerteam.Agile development has gained widespread adoption in the industry and attention in the academic communities. The development methodology has introduced many advantages for the software delivery of the IT solutions, such as a greater focus on interdisciplinary cooperation and early time to market. However, the fast-paced nature of agile development has resulted in concerns regarding the security of the IT solutions being developed. Security practitioners have reported being unable to keep up with the pace of software releases and issues related to cooperation between security practitioners and development teams. There is a need for more research on human-related factors to improve the issues with collaboration. This study investigates trust relationships between development teams and security stakeholders to determine how it affects the work with information security. High levels of team trust have been shown to have beneficial effects on cooperation and team performance. To further investigate trust relationships and the consequences, we have conducted a multiple-case study with semi-structured interviews. Our findings suggest that the trust relationships between the development team and the stakeholder affect the work process related to information security work. The challenges associated with trustworthiness factors are primarily encountered in one direction of analysis; the development team being the trustor and the security stakeholder being the trustee. Challenges are found to be related to four perceived trustworthiness factors: ability, predictability, transparency and benevolence. The consequences of these challenges related to information security work were found to be primarily process-related; developers taking shortcuts, inefficient feedback cycles and a lack of motivation to engage in security work. We provide four recommendations for building trust between the development team and the security stakeholder to improve the work-related information security processes

Investigating trust relationships between software development teams and information security stakeholders

Smidig utvikling har de siste tiårene fått stor oppmerksomhet i IT-industrien og forskningsmiljøet. Utviklingsmetodikken har introdusert mange fordeler for programvareleveranse, blant annet et større fokus på tverrfaglig samarbeid samt raske og hyppige leveranser. Men smidig utvikling har også ført til bekymringer knyttet til sikkerheten til IT-systemene og programvaren utviklet med metodikken. Sikkerhetspersonell rapporterer om at de ikke klarer å holde følge med det høye utviklingstempoet til smidig utvikling. De rapporterer også om problemer med samarbeid mellom ansatte i sikkerhetsroller og utviklere. Smidig utvikling er en metode som baserer seg mye på menneskelige faktorer og samarbeid, og det trengs mer forskning på dette feltet for å løse samarbeidsproblematikken. Tillit i team har vist seg å ha positive konsekvenser for samarbeid og effektivitet. Denne studien undersøker tillitsrelasjoner mellom utviklerteam og sikkerhetsaktører rundt teamet og hvordan tillitsrelasjonene påvirker arbeidet med informasjonssikkerhet i teamene. For å undersøke dette, har vi gjennomført en multiple-case studie med semi-strukturerte intervjuer. Våre funn indikerer at tillitsrelasjoner mellom utviklerteam og sikkerhetsaktører påvirker arbeidsprosessen med informasjonssikkerhet. Utfordringene relatert til troverdighetsfaktorer ble stort sett funnet i én retning av forholdet: når utviklerteamet er den som skal stole på sikkerhetsaktøren. Vi har funnet utfordringer relatert til fire troverdighetsfaktorer; evne, forutsigbarhet, transparens og velvilje. Funn om konsekvenser viser at det var mest prosessrelaterte konsekvenser; utviklere tar snarveier, ineffektiv kommunikasjon mellom aktørene og mangel på motivasjon for å engasjere seg i informasjonssikkerhetsarbeid. Til slutt, foreslår vi anbefalinger for å bygge tillit mellom utviklerteamet og sikkerhetsaktøren for å bedre arbeidet med informasjonssikkerhet i utviklerteam.Agile development has gained widespread adoption in the industry and attention in the academic communities. The development methodology has introduced many advantages for the software delivery of the IT solutions, such as a greater focus on interdisciplinary cooperation and early time to market. However, the fast-paced nature of agile development has resulted in concerns regarding the security of the IT solutions being developed. Security practitioners have reported being unable to keep up with the pace of software releases and issues related to cooperation between security practitioners and development teams. There is a need for more research on human-related factors to improve the issues with collaboration. This study investigates trust relationships between development teams and security stakeholders to determine how it affects the work with information security. High levels of team trust have been shown to have beneficial effects on cooperation and team performance. To further investigate trust relationships and the consequences, we have conducted a multiple-case study with semi-structured interviews. Our findings suggest that the trust relationships between the development team and the stakeholder affect the work process related to information security work. The challenges associated with trustworthiness factors are primarily encountered in one direction of analysis; the development team being the trustor and the security stakeholder being the trustee. Challenges are found to be related to four perceived trustworthiness factors: ability, predictability, transparency and benevolence. The consequences of these challenges related to information security work were found to be primarily process-related; developers taking shortcuts, inefficient feedback cycles and a lack of motivation to engage in security work. We provide four recommendations for building trust between the development team and the security stakeholder to improve the work-related information security processes

The Context of Addressing Power Dynamics in Service Design

To support transformative aims, scholars highlight a crucial need for increased attention to power dynamics in service design (SD). Current literature emphasizes the need for individual service designers to build reflexivity around power without much consideration for their surrounding context. This narrow focus may inadvertently reinforce existing power dynamics while using service designers as scapegoats for the persistent problem. Drawing from ecological theories in psychology, this article provides a framework for understanding the contextual factors that contribute to the lack of reflexivity around power dynamics among service designers. Based on our own experiences and a review of SD literature, we used this framework to identify domains of contextual factors that inhibit service designers to address power dynamics in practice. By proposing a systemic framework and identifying related contextual factors, this study helps to provide grounding for future research and action within the service design community regarding the structural changes needed to address power dynamics

Unsteady flow analysis of hinged and sliding door openings

Existing thermal condition and indoor air quality have a big impact on our work performance, comfort, and health in an indoor environment. Apart from many other parameters, door motions and human movements play crucial role in mass and thermal exchange affecting safety and/or energy management issues in various situations. An isolation room in a hospital setup, for instance, helps to protect patients and staff against the risk of infection by airborne pathogens. Another example is cold storage room facilities, where temperature and moisture control are the key parameters for an optimal operation and energy usage. In this study, we present a transient flow analysis of door motions in indoor environment. The flow physics is resolved by solving 3D compressible RANS (Reynolds-averaged Navier-Stokes) equations together with the energy and species transport equations and two-equation turbulence models utilizing an overset mesh strategy to address the rigid body motion of doors in a relevant fluid domain involving air and sulfur hexafluoride (SF6). Simulations are performed for three different types of doors, namely a hinged door, a two-way sliding door, and a sliding door considering door opening and closing phases. Transient flow-field data through the door opening area have been processed and a comparative analysis is performed considering the mass flux of the constituents, normal velocity, cumulative mass exchange through the different doors