Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2006. / Härtill 3 uppsatser.

Thesis (Ph. D.)--University of Washington, 1993. / Vita. Includes bibliographical references (leaves [145]-169).

Thesis (M.Sc.Eng.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Boiling heat transfer is a critical process in large-scale industrial applications such as steam engines and heat exchangers in power plants, and in microscopic heat transfer devices such as heat pipes and microchannels for cooling electronic chips. Enhancing boiling heat transfer thus has great significance on lots of energy transportation and utilization systems. Recent studies has suggested that micro/nano structured surfaces can produce considerably different boiling heat transfer curves than normal plain surfaces, resulting in different values of the critical heat flux (CHF) and heat transfer coefficient (HTC). In this thesis, pool boiling on several new micro/nano structured surfaces was experimentally investigated to further understand the mechanism of boiling heat transfer and increase boiling performance. We first evaluated enhanced boiling heat transfer on three kinds of micro/nano structured super-hydrophilic surfaces: 1) nanowire coated super-hydrophilic surfaces, 2) hybrid microscale cavity and nanowire structured surfaces and 3) hybrid microscale pillar and nanowire structured surfaces. All three surfaces showed significant enhancement of CHF and HTC compared to plain silicon surfaces. Combined micro/nano structured surfaces presented better performance than nanowire coated surfaces suggesting that both active nucleation density and surface roughness significantly affect boiling heating transfer. Experimental investigations indicate an optimum design both in size (~ 20μ𝑚) and density (between 0 and 10000=cm^2) of cavities for microscale cavity/nanowire structured surfaces. The highest CHF and peak HTC values were obtained on microscale pillar/nanowire structured surfaces. Among the test surfaces, the largest enhancements of CHF and peak HTC were 228% and 298%, respectively, compared to plain silicon surfaces. For a better understanding of the boiling phenomena, pool boiling on super-hydrophobic surfaces was also studied. We found that, for super-hydrophobic surfaces, the major heat transfer mechanism at the initial boiling regime is natural convection of liquid water. In conclusion, micro/nano structured surfaces can greatly influence nucleate boiling heat transfer. The various physical attributes employed with the structured surfaces further revealed the profound influence of surface topography on enhancing boiling heat transfer. / 2031-01-01

abstract: Chloroform (CHCl3) is an important atmospheric pollutant by its direct health effects as well as by its contribution to photochemical smog formation. Chloroform outgassing from swimming pools is not typically considered a source of atmospheric CHCl3 because swimming pools are scarce compared to other sources. However, large urban areas in hot climates such as Phoenix, AZ contain a substantial amount of swimming pools, potentially resulting in significant atmospheric fluxes. In this study, CHCl3 formation potential (FP) from disinfection of swimming pools in Phoenix was investigated through laboratory experiments and annual CHCl3 emission fluxes from swimming pools were estimated based on the experimental data. Swimming pool water (collected in June 2014 in Phoenix) and model contaminants (Pharmaceuticals and Personal Care Products (PPCPs), Endocrine Disrupting Compounds (EDCs), artificial sweeteners, and artificial human waste products) were chlorinated in controlled laboratory experiments. The CHCl3 production during chlorination was determined using Gas Chromatography-Mass Spectrometry (GC-MS) following solid-phase microextraction (SPME). Upon chlorination, all swimming pool water samples and contaminants produced measureable amounts of chloroform. Chlorination of swimming pool water produced 0.005-0.134 mol CHCl3/mol C and 0.004-0.062 mol CHCl3/mol Cl2 consumed. Chlorination of model contaminants produced 0.004-0.323 mol CHCl3/mol C and 0.001-0.247 mol CHCl3/mol Cl2 consumed. These numbers are comparable and indicate that the model contaminants react similarly to swimming pool water during chlorination. The CHCl3 flux from swimming pools in Phoenix was estimated at approximately 3.9-4.3 Gg/yr and was found to be largely dependent on water temperature and wind speed while air temperature had little effect. This preliminary estimate is orders of magnitude larger than previous estimates of anthropogenic emissions in Phoenix suggesting that swimming pools might be a significant source of atmospheric CHCl3 locally. / Dissertation/Thesis / Masters Thesis Chemistry 2014

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Amy R. Betz / Boiling is a very effective way of heat transfer due to the latent heat of vaporization. Large amount of heat can be removed as bubbles form and leave the heated surface. Boiling heat transfer has lots of applications both in our daily lives and in the industry. The performance of boiling can be described with two important parameters, i.e. the heat transfer coefficient (HTC) and the critical heat flux (CHF). Enhancing the performance of boiling will greatly increase the efficiency of thermal systems, decrease the size of heat exchangers, and improve the safety of thermal facilities. Boiling heat transfer is an extremely complex process. After over a century of research, the mechanism for the HTC and CHF enhancement is still elusive. Previous research has demonstrated that fluid properties, system pressures, surface properties, and heater properties etc. have huge impact on the performance of boiling. Numerous methods, both active and passive, have been developed to enhance boiling heat transfer. In this work, the effect of pressure was investigated on a plain copper substrate from atmospheric pressure to 45 psig. Boiling heat transfer performance enhancement was then investigated on Teflon© coated copper surfaces, and graphene oxide coated copper surfaces under various system pressures. It was found that both HTC and CHF increases with the system pressure on all three types of surfaces. Enhancement of HTC on the Teflon© coated copper surface is contributed by the decrease in wettability. It is also hypothesized that the enhancement in both HTC and CHF on the graphene oxide coated surface is due to pinning from micro and nanostructures in the graphene oxide coating or non-homogeneous wettability. Condensation and freezing experiments were conducted on engineered surfaces in order to further characterize the pinning effect of non-homogeneous wettability and micro/nano structure of the surface.

No description available.

Johannesburg's urban fabric is characterised by fragmentation. The natural landscape beyond and its remnants in the city are absorbed in a diffuse urban landscape. In the development of the public park in Yeoville, it is evident that an escalation in the population exacerbates urban expansion characterised by fragmentation and dissolution of the urban form. The scheme proposes the use water for leisure as a means to establish a relationship between the city's users and the natural environment. In the pursuit of responsive urban place making control is taken over the effect of fragmentation on urban development in the park and the fantastical nature as well as the use of water is considered in public urban spaces where it has largely been absent. An existing pool is the catalyst for the programme of swimming and recreation where unbounded fantasy transcends the user from the physical boundaries of the pools of water to become one with the natural environment. The proliferation of existing types of fragments fi nds expression in a series of courtyards that are spatial types of enclosure that offer retreat and seclusion from the context to meet the demands of the overburdened public space. The use and inherent nature of water informed the form and concept of water collection, storage, treatment and use for swimming and cleansing and is central to the narrative of navigation of the courts and pools. The value of the architecture as a contextual response lies in the exploration of the manifold relationships between the city user, urban fabric and the natural environment and urban as well as human scale at which the haptic experience unfolds. / Johannesburg se stedelike weefsel word gekenmerk deur fragmentasie. Die natuurlike landskap en dit wat daarvan oor is in die stad word in 'n uiteenlopende en verbrokkelende stedelike landskap geabsorbeer. In die ontwikkeling van die publieke park in Yeoville, is dit ooglopend dat 'n styging in die bevolking stedelike groei wat gekenmerk word deur fragmentasie en ontbinding van stedelike weefsel, vererger. Die skema beoog om deur middel van water gebruik vir plesier 'n verhouding te vestig tussen die stedelike gebruiker en hul natuurlike omgewing. In die strewe na reaktiewe stedelike plekmaak word beheer geneem oor die effek wat fragmentasie op stedelike ontwikkeling in die park het en die fantastiese natuur sowel as die gebruik van water word oorweeg in publieke stedelike ruimtes waar dit grootliks nagelaat was. 'n Bestaande publieke swembad is die katalis vir 'n program van swem en ontspanning waar die gebruiker deur ontbonde fantasie fi siese grense van poele water oortref om een met hul natuurlike omgewing te word. Die doelbewuste voortbestaan en groei van bestaande fragment-tipes vind uitdrukking in 'n reeks binnehowe wat ruimtelike tipes van omsluiting - wat afsondering van die konteks te weeg bring - om die vereistes van oorlaaide publieke ruimtes te verlig. Die gebruik en inherente natuur van water het die vorm en konsep van water-opgaarding, berging, behandeling en gebruik vir swem en reiniging ingelig en is 'n kerngedagte in die narratief van ontdekking van die binnehowe en poele. Die waarde van die argitektuur as kontekstuele reaksie l? in die ondersoek na die meervoudige verhoudings tussen die stadsgebruiker, stedelike weefsel en die natuurlik omgewing op 'n stedelike sowel as 'n menslike skaal waar 'n tasbare ervaring ontvou. / Mini Dissertation (MArch (Prof))--University of Pretoria, 2016. / Architecture / MArch (Prof) / Unrestricted

This research stems from the need by organisations to retain their key talent in the context of the change in the psychological contract manifesting in the emergence of boundaryless careers. Employees have ceased to be loyal to one organisation and this has marginalised employers as they still need to retain their key talent as a source of competitive advantage. Most organisations have segmented their workforce to develop talent pools of high potential employees to meet the organisation’s current and future critical skills needs. Hence, this study investigates the impact of inclusion in the talent pool on the psychological contract. Various instruments in the literature study were used to measure the psychological contract of employees in the talent pools in comparison to those not in talent pools. These include the transactional and relational psychological contract instrument by Millward and Hopkins (1998), organisational citizenship behaviour by Coyle-Shapiro (2002), trust by Robinson and Rousseau (1994) and turnover intention by Blomme et al. (2010). The study presents findings from 195 employees from three different organisations, about 50% of whom were in talent pools. The study shows that both groups of employees in and outside talent pools consider their psychological contract with their employers as less transactional. Although being part of the talent pool has a positive impact on the relational psychological contract and organisational commitment, it does not necessarily translate into trust and the intention to stay with organisations. Employees in talent pools are not different to those not in talent pools with regard to trust and the turnover intention. The report offers insights aimed at managers to understand the psychological contracts of their employees within the talent pools to avoid unnecessary violations and to explore new value propositions that are aligned to those contracts. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

Preporsition for bachelor thesis project, working from the inside and out. Emphasising spatial quality and experience, More or less ignoring form and program. I’ve had issues with these aspects in earlier project, the form or the program takes alot of place in the project. I haven’t tried this approach before, it’s an attractive thought to allow the project take a form of it’s own, enclosing those spaces i create. The initial concept was to place the pools on the ground (not digging them into the ground) making them volumes that divide and define spaces. Also shifting the interaction between those in the water and those walking alongside the edges. The ceiling should mirror the spaces created by the pool. sinking down over some areas and opening up above others. My process is usually exploratory, I find something i can’t undestand or something where i can’t image the outcome. I play with this until patterns emerge or i feel i can control it. In that stage the inspiration vains. It’s magical to experiencing new things and constantly learning. When i come to that state the project tends to generate itself. During this thesis project I want to define my own process. I want to put it into words in order to understand it myself, but also in order to communicate it to others. Map it all out and hopefully find what makes a project selfgenerating. Filter everything and find the essence of what i’ve learned from my education.

Mitt projekt består av ett kombinerat folkets hus och vad jag kallar ”centrum för fysisk aktivitet”, där en viktig del för mig är att främja alla sorters fysisk aktivitet där tävlingssporter inte nödvändigtvis prioriteras, och där det kan finnas någonting för alla. Den till ytan största enskilda delen av plusprogrammet, bassängen, är till skillnad från den klassiska badhusbassängen inte utformad för tävlingssim utan för att främja lek och andra vattenaktiviteter. Detta görs genom en irregulär form där flera mindre rumsligheter skapas, där man kan organisera allt från vattengympa och rehabiliterande träning, till simskola och lek. Andra viktiga delar av plusprogrammet är danssalen och tre aktivitetsrum, där tanken är att dessa rum inte ska vara alltför programmerade utan ska kunna användas till en rad olika aktiviteter baserat på önskemål och behov. Exempel på sådana aktiviteter skulle kunna vara dans, kampsport, rehabiliterande träning, yoga, och så vidare. Idén till detta kom ur att den enda träningsanläggningen som finns i området är en bollplan och en bollhall, och de närmaste faciliteterna för andra typer av träning ligger i Nynäshamn, med undantag från en simhall i närliggande Ösmo som just nu är planerad att rivas. Det här känns alltså som någonting som området skulle kunna dra mycket nytta av. Tanken med gestaltningen var att skapa en byggnad som blir en del av skogskanten och som fortsätter in i skogen. Strukturen baseras därför på pelare och vertikala modulliknande delar som följer skogens och markens form. Materialet är i huvudsak trä, och de spridda pelarna samt takfönster utplacerade här och var stärker känslan av att vara ute i skogen. De olika delarna av byggnaden – pelare, rumsligheter, och fönster – är utplacerade med en viss irregularitet och lekfullhet för att gynna den mer naturliga känslan. / My project consists of a combined people's house and what I call a "centre for physical activity", where an important part for me is to promote all kinds of physical activity where competitive sports are not necessarily prioritized, and where there can be something for everyone. The largest individual part of the plus program, the pool, unlike the classic bathhouse pool, is not designed for competitive swimming but to promote play and other water activities. This is done through an irregular shape where several smaller spaces are created, where you can organize everything from water gym and rehabilitative training, to swimming school and play. Other important parts of the plus program are the dance hall and three activity rooms, where the idea is that these rooms should not be overly programmed but should be able to be used for a range of different activities based on wishes and needs. Examples of such activities could be dance, martial arts, rehabilitative exercise, yoga, and so on. The idea for this came from the fact that the only training facility available in the area is a ball field and a ball hall, and the nearest facilities for other types of training are in Nynäshamn, with the exception of a swimming hall in nearby Ösmo which is currently scheduled to be demolished. So this feels like something that the area could greatly benefit from. The idea with the design was to create a building that becomes part of the edge of the forest and that continues into the forest. The structure is therefore based on pillars and vertical module-like parts that follow the shape of the forest and the ground. The material is mainly wood, and the scattered pillars and skylights placed here and there strengthen the feeling of being out in the forest. The various parts of the building – columns, spaces, and windows – are placed with a certain irregularity and playfulness to favor the more natural feel.