The recent addition to Stockholm’s built environment in the shape of the new Slussen bridge, or Guldbron as most locals call it, has been both a source of controversy and admiration. This reaction is typical of any infrastructure that reshapes our surroundings. However, this interaction is not unidirectional. Similar projects may be affected by the very relations they might trigger in the first place. Building upon the conjunction of crucial concepts from actor-network theory and assemblage thinking, this study intends to identify the co-producing nature of the bridge as a technical artefact and the relations surrounding the project. To that end, I employ a qualitative research technique combining various methods of interviews and observation. The research primarily identifies the desired nature of the bridge and its ability to stabilize relations as a heterogeneous assemblage. Ultimately, the everchanging state of affairs or fluid character of this piece of infrastructure is discussed. The thesis concludes by arguing that the exploration of similar projects from a relational perspective challenges the conceptualization of megaprojects as taken- for-granted entities. Such an understanding brings to the forefront the crucial importance of interactions to define whether a project can be considered as ‘mega’, as opposed to employing a prescribed set of criteria.

Although the global energy demand is shifting towards a well-balanced energy mix, fossil fuels will continue to have a significant role in this transition and will maintain a big share in the energy mix portfolio. The production of oil and gas has already reached the apex in the time that most of the conventional giant reservoirs are depleting, and discoveries for new reserves have shrunk down. In conventional reservoirs, it is estimated that about two-thirds of the Original Oil in Place (OOIP) will not be produced within the field lifecycle, corresponding to an average Recovery Factor (RF) between 20% and 40%. This low recovery factors from traditional methods trigger more investments in the Enhanced Oil Recovery (EOR) techniques. Waterflooding is one of the most commonly used technique to increase RF by raising or maintaining reservoir pressure. Lack of comprehending the driving forces in Naturally Fractured Reservoirs and reservoir heterogeneity may lead to serious conformance problems in which dealing with excessive undesirable water production becomes very challenging. Chemical EOR through an injection of a polymer solution is amongst the tested options that can be used to improve sweep efficiency. Ultimately, understanding the reservoir characteristics and having the know-how to implement the best recovery option will help to maximize the field’s lifecycle and increase the RF. Therefore, this study investigates some key elements that have a significant influence on the overall fluid flow behavior. The work reveals insights on the impact of capillarity and wettability in heterogeneous porous media. An experimental lab-scale consisting of a 2D sandbox model, which mimics a water-wet fractured system with injection and production ports, was designed, fabricated, and tested in single-phase and two-phase flow scenarios including the injection of water and polymer solutions. In the case of single-phase flow, a waterflood baseline scenario was studied with controlled variables, which helped to distinguish the contrast with the polymer flood case. Implementing water injection in a fractured water-wet reservoir showed that water prefers to channel through high permeable streaks, which consequently leads to poor volumetric sweep leading to significant bypassed zones. Investigating the two-phase flow was the essence of this research. Thus, the same procedures were repeated where water and polymer were used to displace oil. During waterflooding, due to strong capillarity contrast between the matrix and fracture media, flow divergence was found to be faster towards the matrix medium where the matrix gets saturated faster than that the fracture, overriding the high permeability of the fracture. Whereas, polymer flooding exhibited better volumetric sweep in all scenarios. Numerical simulations were used to replicate the experiments. This work can give new visual insights about key recovery mechanisms in heterogeneous reservoirs using polymers.

CPU-memory bottleneck is a widely recognized problem. It is known that majority of high performance computing (HPC) database systems are configured with large memories and dedicated to process specific workloads like weather prediction, molecular dynamic simulations etc. My research on optimal address mapping improves the memory performance by increasing the channel and bank level parallelism. In an another research direction, I proposed and evaluated adaptive page migration techniques that obviates the need for offline analysis of an application to determine page migration strategies. Furthermore, I explored different migration strategies like reverse migration, sub page migration that I found to be beneficial depending on the application behavior. Ideally, page migration strategies redirect the demand memory traffic to faster memory to improve the memory performance. In my third contribution, I worked and evaluated a memory-side accelerator to assist the main computational core in locating the non-zero elements of a sparse matrix that are typically used in scientific, machine learning workloads on a low-power embedded system configuration. Thus my contributions narrow the speed-gap by improving the latency and/or bandwidth between CPU and memory.

The fact that hydrogen is a clean and versatile fuel offers an attractive carbon-free source of energy and leverages the U.S. economy toward long-term sustainable economic growth. At an industrial scale, hydrogen production is mostly relying on methane steam reforming producing stoichiometric amounts of carbon oxides (CO and CO2), which imposes economic and environmental concerns. To mitigate the issue, we propose NH3 assisted anaerobic reforming of natural gas liquids (ethane and propane) as an alternative approach to produce COx free hydrogen. Here, in the first chapter, through comprehensive performance evaluation, characterization, and transient kinetic studies, it is shown that the atomically dispersed Re-oxo grafted into framework Al of the HZSM-5 zeolite are highly active and stable for the ammonia reforming of ethane and propane at temperatures comparable to steam reforming ≤ 650 °C. In the second chapter, an alternative non- noble Ni/Ga intermetallic compound (IMC) with various Ni to Ga ratios is synthesized through the solvothermal synthesis by forming the oxalate MOF precursor. The result indicates that while Ni-rich samples form pure Ni3Ga IMC with promising catalytic performance, the Ga rich catalyst consists of segregated phases of Ni/Ga IMC and Ga2O3 with ill-defined structure showing lower stability despite the high activity. In chapter 3, a bifunctional Ni/Ga supported ZSM-5 is successfully developed in ethane aromatization. Influence of metal function in early-stage and steady-state activity and stability as well as structure reactivity relation was investigated applying comprehensive characterization, performance test, deactivation modeling, and transient studies. The results suggest that a tandem reaction mechanism between Ni3Ga intermetallic compound, Ga cation, and Bronsted acid sites of zeolite is responsible for the superior performance of bimetallic catalysts compared to their monometallic counterpart. In the last chapter, applying transient kinetic technique, the mechanism of ethane aromatization over Pt and Zn supported ZSM-5 model catalysts was precisely explored. The results reveal that despite mechanistic differences between these catalysts, ethane amortization on both catalysts follows a hydrocarbon pool mechanism.

Automatic Heterogeneous Compilers allows blended hardware-software solutions to be explored without the cost of a full-fledged design team, but limited research exists on current partitioning algorithms responsible for separating hardware and software. The purpose of this thesis is to implement various partitioning algorithms onto the same automatic heterogeneous compiler platform to create an apples to apples comparison for AHC partitioning algorithms. Both estimated outcomes and actual outcomes for the solutions generated are studied and scored. The platform used to implement the algorithms is Cal Poly’s own Twill compiler, created by Doug Gallatin last year. Twill’s original partitioning algorithm is chosen along with two other partitioning algorithms: Tabu Search + Simulated Annealing (TSSA) and Genetic Search (GS). These algorithms are implemented inside Twill and test bench input code from the CHStone HLS Benchmark tests is used as stimulus. Along with the algorithms cost models, one key attribute of interest is queue counts generated, as the more cuts between hardware and software requires queues to pass the data between partition crossings. These high communication costs can end up damaging the heterogeneous solution’s performance. The Genetic, TSSA, and Twill’s original partitioning algorithm are all scored against each other’s cost models as well, combining the fitness and performance cost models with queue counts to evaluate each partitioning algorithm. The solutions generated by TSSA are rated as better by both the cost model for the TSSA algorithm and the cost model for the Genetic algorithm while producing low queue counts.

An emerging trend in computing is to use distributed heterogeneous computing (HC) systems to execute a set of tasks. Cluster computer systems, grids, and Desktop Grids are three popular kinds of HC systems. An important component of an HC system is its resource management system (RMS). The main responsibility of an RMS is assigning resources to tasks in order to satisfy certain performance requirements. For cluster computer systems, we propose a new mapping heuristic which requires less state information than current heuristics. For Desktop Grids, we propose a new scheduling policy that exploits knowledge of the effective computing power delivered by the machines and the distribution of their fault times in order to improve performance. Finally, for grids, we propose a new decentralized load balancing policy which dramatically cuts down the communication overhead incurred in state information update. The proposed resource management policies utilize the solution to a linear programming problem (LP) which maximizes the system capacity. Our simulation experiments show that these policies perform very competitively, especially in highly heterogeneous systems. / Thesis / Doctor of Philosophy (PhD)

Examination of peat samples collected from hummocks and hollows within a confined bog reveals that peat collected from different locations, designated by surface topography, vary in ash content, ash alkalinity, initial Kjeldahl nitrogen content, and fixed and total nitrogen after ammoniation with an ammonia-air mixture. The values of these properties have shown hummocks and hollows to be true entities having characteristic ranges of certain properties. The results have shown that, although peat is heterogenous with respect to certain properties, use can still be made of determined values if ranges of these values are recognized and utilized. Misinterpretations and meaninglessness of results are possible if this is not done. / Thesis / Master of Science (MSc)

No description available.

No description available.

No description available.