The aim of this work to study the solar chimney installed in the EPT-lab of the NTNU. The work starts with the development of a CFD model of the solar chimney and comparing with the experimental data, showing a good accuracy of the CFD results. The CFD model is used to compare three types of solar chimneys for different heights and width; obtained that the chimney installed in the EPT-lab gets higher flow rates in the most of the most of the cases. The CFD model shows a uniform temperature and velocity inside the chimney that allows developing a simple physical model of the chimney, which gives a good precision of results. Finally a simplification of the solar chimney and other systems installed in a building is simulated and also is developed another physical model for this kind of building, giving an idea of the behavior of this solar house in diverse conditions.

During the last decades the exploitation of energy from the wind has become one of the most promising renewable energy technologies. The main strive in today’s development of wind turbines is to increase the efficiency of the turbine and to build bigger rotors that are able to extract more power out of the wind.When it comes to the planning and designing of a wind park, also the aerodynamic interactions between the single turbines must be taken into account. The flow in the wake of the first row turbines is characterized by a significant deficit in wind velocity and by increased levels of turbulence. Consequently, the downstream turbines in a wind farm cannot extract as much power from the wind anymore. Furthermore, the additional turbulence in the wake could be a reason for increased material fatigue through flow-induced vibrations at the downstream rotor.The main focus of this experimental study is to investigate the local velocity deficit and the turbulence intensities in the wake behind an array of two model wind turbines. For two different turbine separation distances, the wake is scanned at several different downstream positions behind the second model turbine. Thus, it is possible to map the axial development of mean velocity and turbulence intensity and to evaluate the influence of turbine separation distance. Furthermore, the effect of varying tip speed ratios of the first and second turbine onto the wake flow field is investigated.The experiments are performed at the wind tunnel (1.9m x 2.7m cross section) at NTNU Trondheim using two model wind turbines with a rotor diameter of 0.9m. A hot wire probe is used to scan the wake behind the model turbines in defined positions.The velocity deficit and the turbulence intensity behind an array of two turbines are found to be significantly higher than behind one unobstructed turbine. Moving axially downstream, a gentle broadening of the wake can be observed. The wake profiles measured in close distances behind the rotor are characterized by evident asymmetries. Further downstream in the wake, the flow field becomes more symmetrical. The flow conditions in the inner part of the wake behind the two turbines are observed to be mainly dominated by the operational characteristics of the second turbine rotor. Although the first turbine has hardly any influence on the inner part of the wake, the outer dimensions of the wake can be tracked back to the influence of the first turbine.

In XX century, Pavement Management System has became obligatory to be used by road agencies. Need of serviceable road system demands the proper maintenance and rehabilitation plans and at that point, Pavement Performance Models step in. They are used to predict the future condition of pavement structure, basing mostly on road, climate and traffic data.The following thesis describes the attempts to implement modern Pavement Performance Models in Norway. With their help, it would be possible to predict pavement’s deterioration in better way and therefore, perform better plan maintenance and rehabilitation of the road systems.First chapter of the thesis describes the theory of Pavement Management System. It explains what Pavement Management System is and what are its levels. Later in the chapter, some of the Pavement Performance Models are described. They were considered as potentially relevant for calibration to Norwegian conditions by NordFoU- the Scandinavian co-operation program. The work of NordFoU was also described here.The historical data from Nasjonal Vegdatabank (NVDB) are described in the Chapter 3. Graphs show the rutting in all subsections on two roads- E6 and Fv 704 in Sør- Trøndelag, in Norway. E6 represents the roads with big traffic and Fv704- regional roads with small traffic. The methods of gathering road data by Statens Vegvesen are also described.In Chapter 4, the equations for calculations are shown. All equations have been adopted from the papers published by NordFoU, which are based on the HDM-4 manuals. Some of the equations come from Swedish guidelines about back- calculating E- moduli of the pavement layers. This chapter also contains assumptions and values of the coefficients that were used in calculations within following thesis. Optimisation of calibration factors was done in Excel Solver. These calculations can be found in Appendixes 7, 8, 9 and 10.The results of the calculations are shown in Chapter 5. The measured and calculated results are compared. The model of rutting has shown good correlation with reality. For E6, over 90 % of data were covered with the model. For Fv 704, the correlation was a bit worse, but still satisfactory. Value of coefficient of determination (R2) was calculated to be 58 % using the roughness model. However, in order to get better value, it is possible to further calibrate the model by modifying length of the sections and by using a new measuring equipment (ViaPPS).Chapter 6 includes the conclusion for the performed calibration and HDM-4 models. The correlation between the models and reality has been discussed. The use of studded tyres is observed to be the main contributor to deepening of the mean rut depth, other factors have negligible effect on rutting.In the following thesis calibration of only two HDM-4 models was performed. The two models were rutting and roughness respectively. A good correlation was obtained, however it is recommended to work on roughness and climate models. The rest of the models in a program can be calibrated in the future, after gathering more detailed road data, such as edge- break and cracking.

As the worldwide energy consumption continues to grow, natural gas and especially LNG are expected to keep contributing significantly with this growth. More than 95% of the installed LNG facilities use a precooling cycle as the first stage of the liquefaction process. In this work, a technical comparison between different precooling cycles for LNG processes is carried out through computational simulations using Aspen HYSYS®. The aim is to provide future project developments with a clear idea of the technical advantages/disadvantages involved in the selection of the process for the precooling cycle in LNG processes. The precooling circuit is treated as a stand-alone cycle first and then implemented in an entire liquefaction process; the propane precooled mixed refrigerant (C3MR) and the mixed fluid cascade (MFC®) processes are used for this purpose. The parameters studied are essentially coefficient of performance (β), heat exchanger UA value, compressor power, suction volumetric flow and pressure ratio. Two cases, cold (6 °C) and warm (25 °C) climate conditions are considered for each study.A three stage propane precooled process was found to be the most energetically efficient among the studied cases, even better than a two stage mixed refrigerant process (C2/C3) for both climate conditions; however, the performance in terms of energy consumption is not the only parameter taken into account and therefore a selection chart is provided. Under warm climate conditions a propane precooling circuit showed to be the most recommended process. For cold climates, however, a two stage mixed refrigerant cycle reaching ca. -50 °C is the preferred alternative, since in this case the low ambient temperature gives the propane precooled process a low share in the entire process. Other cases, such as a single stage mixed refrigerant cycle and a mixed refrigerant including n-Butane are taken into account. Based on the obtained results, a new, highly efficient configuration for natural gas liquefaction has been suggested, it is to be implemented in relatively warm climate conditions. It consists of a MFC® process with modifications in the liquefaction cycle and a propane precooling instead of the mixed refrigerant circuit; no previous reference in the open literature was found for such arrangement.

The aim of this thesis is to determine the efficiency of the hydronic heating system implemented in building with passive envelopes. Thermal losses and energy consumption of the pump are relative values for determining the efficiency.The first step towards this aim is to provide theoretical background for better understanding of the hydronic system. The advantages of this system are also presented.Good knowledge of hydronic systems, first of all, modes of transport of the work fluid and heat distribution into the space, makes a good basis for the next step- designing the system.Once the system is designed, it is possible to create mathematical model. This model together with the input values given enables creation and a running of a simulation program.In the end the results from the simulation are obtained for a typical Norwegian house which satisfies recommendation for the passive house concept.The analyses of our results shows, in spite of the heat losses from the pipes and pump energy consumption, it is feasible to fulfill the prescribed limitations regarding the Passive house energy consumption. Unfortunately, the heat losses values are not negligible and it will eventually disturb thermal comfort.The method derived in this report as well as the simulation program presented can serve as a starting point for future investigation of an assortment of hydronic systems variations. One of the logical choices is certainly a system with insulated pipes. Such system could provide the key advantage of hydronic systems compared to other heating systems. In that way they could present themselves as the best heating solution for future buildings with passive envelopes.

The purpose of this narrative study is to understand the experience of ESL female teachers in postsecondary education. The ESL female teachers will be defined as female teachers who speak English as a second language. The study asks the following research questions: What are the lived experiences of ESL female teachers in postsecondary education? How do ESL female teachers in postsecondary education narrate their experiences and negotiate their teacher identities? How can the above understanding contribute to the inclusion of ESL female teachers in an increasingly diversified educational landscape? The researcher adopts an intersectional stance and a poststructuralist understanding of subjectivity and positioning to study identity. Life story interviews and narrative inquiry are utilized as methodology to collect stories from ESL female teachers teaching in postsecondary education and to retell the same so as to achieve an informed understanding of the phenomenon under study. The study reveals that the participants have experienced an intersection of multiple identities which collectively function to marginalize them under the discourse of difference as deficit. Apart from efforts to adapt to the dominant discourse, the participants have also acted to utilize their multiple identities so as to resist negative positioning. The participants’ experiences have posed questions concerning what institutional and systemic changes are needed in order to help their inclusion in postsecondary education. / Graduate / fuhong2015@gmail.com

This research studied not only the Millennial Generation teachers who have entered the workforce in recent years, but it also compared the perceptions of Black Millennial Generation teachers to those of White Millennial Generation teachers. The intent of this study was to discover whether Black and White Millennial Generation teachers feel prepared to work with diverse groups of students and to reveal additional factors influencing their decisions to remain in education. This study also examined whether there were differences between the perceptions of Black and White Millennial Generation teachers regarding their work/life balance, the amount of support they receive from their administrative team, professional learning opportunities, and other components of their teaching careers. This agenda is relevant because the impact of Millennials on the field of education has only begun to be realized and the percentage of Millennials in the classroom continues to rise. Interviewing six Millennial Generation teachers utilizing a semi-structured interview protocol allowed the researcher to gather data about their perceptions of their ability to work with diverse groups of students and the teaching profession. To make sense of the raw data, a prior-research-driven method was used for data analysis. The Millennial Generation is touted to be the most diverse generation to date. This study found that both Black and White Millennial Generation teachers feel they are able to successfully reach ethnically and socioeconomically diverse groups of students. The subjects for this study reported a high tolerance for and appreciation of ethnic, socioeconomic, and religious diversity.

In rural, low socioeconomic public schools, the diversity of the student population challenges teachers beyond their means to meet the wide-ranging needs of students, and therefore creating opportunity gaps. The purpose of this study was to explore one district's leadership support of teachers to create an equitable learning environment for all students. The present study built on existing literature by discovering leadership practices and perceived necessary supports for closing achievement gaps in K-12 classrooms. Through interviews with district and school administrators, classroom teachers, and observations of leadership meetings, the research for this case study included data collection and analysis. From the interview questions and observations, six themes emerged. The themes revealed from the data collected and analysis for this qualitative study aligned with the components of the conceptual framework, a sequence of initiative requirements for equitable learning environments. Developing a sequence of initiatives among all levels of educators could benefit sustainment of an equitable learning environment in Rural ISD. Recommended for further research is professional development to both leadership and teachers about professional learning communities (PLCs). In addition, study of parent education programs and how relationships achieve more parental involvement requires further research. A final recommendation for collegiate education preparation programs should include parental involvement, differentiation, and small group instruction as a requirement for teacher development when planning instruction for equitable lessons resulting in student achievement.

Keynote plenary

The study involves synthetic approaches towards the preparation of novel NHC complexes of low valent rhenium and manganese transition metals. Diverse methods of synthesis were studied. The direct approach, in which the ylidene obtained from deprotonation of 1,3-bis(2,4,6- trimethylphenyl)imidazolium chloride was added to the metal substrate, proved to be unsuccessful as isolation of the free carbene should rather be performed in an argon filled glove box under extreme inert conditions. By way of further investigation the ylidene was prepared by in situ methods and then quenched with the metal substrate. Different bases for deprotonation purposes and reaction conditions were explored. All routes employed were investigated and compared using group VII transition metal substrates Re(CO)5Br, Mn(CO)5Br, Re2(CO)10 and Mn2(CO)10. Isolation and purification of these products proved to be very challenging due to the insolubility in some organic solvents with consequent problematic spectroscopic analyses of the complexes. The tendency of the products to undergo various side reactions is observed in all reactions. Specifically, hydrolysis of the imidazolium ligand, followed by vinyl formation, yielded the mesitylformamide compound (3). The results obtained for some of the monometal substrates indicated that the target complexes were formed but could not be isolated. However, the synthesis route employing deprotonation by nBuLi as base and [Mn2(CO)10] as dimetal substrate lead to the isolation of the target dinuclear complex [Mn2(CO)9IMes] (9). Other novel complexes obtained during the course of this study include the biscarbene tetrarhenium complex [Re2(CO)9.C(OEt)C4H2OC(OEt)Re2(CO)9] (12) and various side reaction products. In many cases, metal-metal bond cleavage and carbonyl insertion was observed, as is evident in the complex IMesH[ReO4] (6) and ketene product (13). Structural and theoretical studies were performed to investigate the bond character between the carbene ligand and the metal. / Dissertation (MSc)--University of Pretoria, 2010. / Chemistry / unrestricted