Дисертації з теми "Construction Processes not elsewhere classified"
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Csató, Lehel. "Gaussian processes : iterative sparse approximations." Thesis, Aston University, 2002. http://publications.aston.ac.uk/1327/.
Повний текст джерелаAbdullah. "Knowledge sharing processes for identity theft prevention within online retail organisations." Thesis, University of Central Lancashire, 2017. http://clok.uclan.ac.uk/23998/.
Повний текст джерелаPanopoulos, Georgios D. "Economic aspects of safety in the Greek construction industry." Thesis, Aston University, 2003. http://publications.aston.ac.uk/12233/.
Повний текст джерелаShorrock, Sarah. "Protecting vulnerable people : an exploration of the risk factors and processes associated with Lancashire's Multi-Agency Safeguarding Hubs (MASH)." Thesis, University of Central Lancashire, 2017. http://clok.uclan.ac.uk/23075/.
Повний текст джерелаCushing, Karen. "An analysis of the mandatory admission criterion within youth justice diversionary processes." Thesis, University of Bedfordshire, 2016. http://hdl.handle.net/10547/622545.
Повний текст джерелаHermann, Inge. "Cold War heritage (and) tourism : exploring heritage processes within Cold War sites in Britain." Thesis, University of Bedfordshire, 2012. http://hdl.handle.net/10547/326057.
Повний текст джерелаThompson, Diane. "The social and political construction of care : community care policy and the 'private' carer." Thesis, University of Bedfordshire, 2000. http://hdl.handle.net/10547/233629.
Повний текст джерелаWang, Yu. "The development of a novel on-line system for the monitoring and control of fermentation processes." Thesis, University of Bedfordshire, 1995. http://hdl.handle.net/10547/610796.
Повний текст джерела(9155963), Fekadu Debella. "PROFITABILITY IMPROVEMENT OF CONSTRUCTION FIRMS THROUGH CONTINUOUS IMPROVEMENT USING RAPID IMPROVEMENT PRINCIPLES AND BEST PRACTICES." Thesis, 2020.
Знайти повний текст джерелаThe internal and external challenges construction companies face such as variability, low productivity, inefficient processes, waste, uncertainties, risks, fragmentation, adversarial contractual relationships, competition, and those resulting from internal and external challenges such as cost overruns and delays negatively affect company performance and profitability. Though research publications abound, these challenges persist, which indicates that the following gaps exist. Lean construction, process improvement, and performance improvement research have been conducted wherein improvement principles, and best practices are used to ameliorate performance issues, but several knowledge gaps exist. Few companies use these improvement principles and best practices. For those companies applying improvements, there is no established link between these improvements and performance/profitability to guide companies. Further, even when companies use improvement principles and best practices, they apply only one or two, whereas an integrated application of these improvement principles and best practices would be more effective. The other gap the author identified is the lack of strategic tools that construction companies can use to improve and manage their profitability. This thesis tried to fill the knowledge gap, at least partially, by developing a two-part excellence model for profitability improvement of construction companies. The excellence model lays out strategies that would enable companies to overcome the challenges and improve their profitability. The excellence model also gives an iterative and recursive continuous improvement model and flowchart to improve the profitability of construction companies. The researcher used high impact principles, guidelines, and concepts from the literature on organizational effectiveness, critical success factors, strategic company profitability growth enablers, process improvement, and process maturity models, performance improvement, and organizational excellence guidelines to develop the two-part excellence model.
The author also translated the two-part excellence model into the diagnostic tool and Decision Support System (DSS) by use of process diagrams, fishbone diagrams, root cause analysis, and use of improvement principles, countermeasures and best practices at the most granular (lowest intervention) levels to do away with root causes of poor performance. The author developed the diagnostic tool and Decision Support System (DSS) in Access 2016 to serve as a strategic tool to improve and manage the profitability of construction companies. The researcher used improvement principles, and best practices from scientific and practitioner literature to develop company and project process flow diagrams, and fishbone (cause and effect) diagrams for company, department, employee, interactions and project performance for the profitability improvement, which are the engines of the diagnostic tool and DSS. The diagnostic tool and DSS use continuous improvement cycles iteratively and recursively to improve the profitability of construction companies from the current net profit of 2-3 percent to a higher value.
(8770325), Anzy Lee. "RIVERBED MORPHOLOGY, HYDRODYNAMICS AND HYPORHEIC EXCHANGE PROCESSES." Thesis, 2020.
Знайти повний текст джерелаHyporheic exchange is key to buffer water quality and temperatures in streams and rivers, while also providing localized downwelling and upwelling microhabitats. In this research, the effect of geomorphological parameters on hyporheic exchange has been assessed from a physical standpoint: surface and subsurface flow fields, pressure distribution across the sediment/water interface and the residence time in the bed.
First, we conduct a series of numerical simulations to systematically explore how the fractal properties of bedforms are related to hyporheic exchange.We compared the average interfacial flux and residence time distribution in the hyporheic zone with respect to the magnitude of the power spectrum and the fractal dimension of riverbeds. The results show that the average interfacial flux increases logarithmically with respect to the maximum spectral density whereas it increases exponentially with respect to fractal dimension.
Second, we demonstrate how the Froude number affects the free-surface profile, total head over sediment bed and hyporheic flux. When the water surface is fixed,the vertical velocity profile from the bottom to the air-water interface follows the law of the wall so that the velocity at the air-water interface has the maximum value. On the contrary, in the free-surface case, the velocity at the interface no longer has the maximum value: the location having the maximum velocity moves closer to the sediment bed. This results in increasing velocity near the bed and larger head gradients, accordingly.
Third,we investigate how boulder spacing and embeddedness affect the near-bed hydrodynamics and the surface-subsurface water exchange.When the embeddedness is small, the recirculation vortex is observed in both closely-packed and loosely-packed cases, but the size of vortex was smaller and less coherent in the closely-packed case. For these dense clusters, the inverse relationship between embeddedness and flux no longer holds. As embeddedness increases, the subsurface flowpaths move in the lateral direction, as the streamwise route is hindered by the submerged boulder. The average residence time therefore decreases as the embeddedness increases.
Lastly, we propose a general artificial neural network for predicting the pressure field at the channel bottom using point velocities at different level. We constructed three different data-driven models with multivariate linear regression, local linear regression and artificial neural network. The input variable is velocity in x, y, and z directions and the target variable is pressure at the sediment bed. Our artificial neural network model produces consistent and accurate prediction performance under various conditions whereas other linear surrogate models such as linear multivariate regression and local linear multivariate regression significantly depend on input variable.
As restoring streams and rivers has moved from aesthetics and form to a more holistic approach that includes processes, we hope our study can inform designs that benefit both structural and functional outcomes. Our results could inform a number of critical processes, such as biological filtering for example. It is possible to use our approach to predict hyporheic exchange and thus constrain the associated biogeochemical processing under different topographies. As river restoration projects become more holistic, geomorphological, biogeochemical and hydro-ecological aspects should also be considered.
(6612953), Benjamin P. Wilkins. "Deciphering Soil Nitrogen Biogeochemical Processes Using Nitrogen and Oxygen Stable Isotopes." Thesis, 2019.
Знайти повний текст джерелаVariations in stable isotope abundances of nitrogen (δ15N) and oxygen (δ18O) of nitrate are a useful tool for determining sources of nitrate as well as understanding the transformations of nitrogen within soil (Chapter 2). Various sources of nitrate are known to display distinctive isotopic compositions, while nitrogen transformation processes fractionate both N and O isotopes and can reveal the reaction pathways of nitrogen compounds. However, to fully understand the δ15N and δ18O values of nitrate sources, we must understand the chemistry and the isotopic fractionations that occur during inorganic and biochemical reactions. Among all N cycle processes, nitrification and denitrification displayed some of the largest and most variable isotope enrichment factors, ranging from -35 to 0‰ for nitrification, and -40 to -5‰ for denitrification. In this dissertation, I will first characterize the isotopic enrichment factors of 15N during nitrification and denitrification in a Midwestern agricultural soil, two important microbial processes in the soil nitrogen cycle. Nitrification incubations found that a large enrichment factor of -25.5‰ occurs during nitrification NH4+ è NO3-, which agrees well with previous studies (Chapter 3). Additionally, oxygen isotopic exchange that occurs between nitrite and water during nitrification was also quantified and found that 82% of oxygen in NO3- are derived from H2O, much greater than the 66% predicted by the biochemical steps of nitrification. The isotopic enrichment that occurs during denitrification was assessed by measuring the change in δ15N as the reactant NO3- was reduced to N2 gas (Chapter 4). The incubations and kinetic models showed that denitrification can causes large isotopic enrichment in the δ15N of remaining NO3-. The enrichment factor for NO2- è gaseous N was -9.1‰, while the enrichment factors for NO3- è NO2- were between -17 to -10‰, both of which were within the range of values report in literature. The results demonstrated that nitrification and denitrification caused large isotope fractionation and can alter the presumed δ15N and δ18O values of nitrate sources, potentially leading to incorrect apportionment of nitrate sources.
The results of the denitrification incubation experiments were applied to a field study, where the measured enrichment factor was utilized to quantify loss of N by field-scale denitrification (Chapter 5). Field-based estimates of total denitrification have long been a challenge and only limited success has been found using N mass balance, N2O gas flux, or isotope labeling techniques. Here, the flux of nitrate and chloride from tile drain discharge from a small field was determined by measuring both dissolved ions (ion chromatography) and monitoring water discharge. The δ15N and δ18O of tile nitrate was also measured at a high temporal resolution. Fluxes of all N inputs, which included N wet and dry deposition, fertilizer application, and soil mineralization were determined. The d15N and d18O values of these nitrate sources was also determined. Using this data, I first detected shifts in δ15N and δ18O values in the tile drain nitrate, which indicated variable amounts of denitrification. Next, a Rayleigh distillation model was used to determine the fraction of NO3- loss by field scale denitrification. This natural abundance isotope method was able to account for the spatial and temporal variability of denitrification by integrating it across the field scale. Overall, I found only 3.3% of applied N was denitrified. Furthermore, this study emphasized the importance of complementary information (e.g. soil moisture, soil temperature, precipitation, isotopic composition of H2O, etc.), and the evidence it can provide to nitrogen inputs and processes within the soil.
(6629942), Anna N. Tatara. "Rate Estimators for Non-stationary Point Processes." Thesis, 2019.
Знайти повний текст джерела(5930969), Augustine M. Agyemang. "THE IMPACTS OF ROAD CONSTRUCTION WORK ZONES ON THE TRANSPORTATION SYSTEM, TRAVEL BEHAVIOR OF ROAD USERS AND SURROUNDING BUSINESSES." Thesis, 2019.
Знайти повний текст джерелаIn our daily use of the transportation system, we are faced with several road construction work zones. These construction work zones change how road users interact with the transportation system due to the changes that occur in the system such as increased travel times, increased delay times and vehicle stopped times. A microscopic traffic simulation was developed to depict the changes that occur in the transportation system. The impacts of the changes in the transportation system on the human travel behavior was investigated using ordered probit and logit models using five independent variables; age, gender, driving experience, annual mileage and percentage of non-work trips. Finally, a business impact assessment framework was developed to assess the impact of the road construction work zones on various businesses categories such as grocery stores, pharmacy, liquor stores and fast foods. Traffic simulation results showed that the introduction of work zones in the road network introduces an increase in delay times, vehicle stopped times, and travel times. Also, the change in average travel times, delay times and vehicle stopped times differed from road link to link. The observed average changes saw an increase as high as 318 seconds per vehicle, 237 seconds per vehicle and 242 seconds per vehicle for travel time, delay time and vehicle stopped time, respectively, for the morning peak period. An average increase as high as 1607 seconds per vehicle, 258 seconds per vehicle and 265 seconds per vehicle was observed for travel time, delay time and vehicle stopped time, respectively, for the afternoon peak period. The statistical model results indicated that, on a work trip, a high driving experience, high annual mileage, and high percentage of non-work trips makes an individual more likely to change their route. The results also showed gender difference in route choice behavior. Concerning business impacts, businesses in the work zone were impacted differently with grocery and pharmacy stores having the highest and lowest total loss in revenue, respectively.
(5930708), David J. Kortge. "Simulation, Construction, and Testing of a Lloyd's Mirror Lithographic Interferometer." Thesis, 2019.
Знайти повний текст джерела(9757040), Lina M. Aboulmouna. "Towards cybernetic modeling of biological processes in mammalian systems—lipid metabolism in the murine macrophage." Thesis, 2020.
Знайти повний текст джерелаRegulation of metabolism in mammalian cells is achieved through a complex interplay between cellular signaling, metabolic reactions, and transcriptional changes. The modeling of metabolic fluxes in a cell requires the knowledge of all these mechanisms, some of which may be unknown. A cybernetic approach provides a framework to model these complex interactions through the implicit accounting of such regulatory mechanisms, assuming a biological “goal”. The goal-oriented control policies of cybernetic models have been used to predict metabolic phenomena ranging from complex substrate uptake patterns and dynamic metabolic flux distributions to the behavior of gene knockout strains. The premise underlying the cybernetic framework is that the regulatory processes affecting metabolism can be mathematically formulated as a cybernetic objective through variables that constrain the network to achieve a specified biological “goal”.
Cybernetic theory builds on the perspective that regulation is organized towards achieving goals relevant to an organism’s survival or displaying a specific phenotype in response to a stimulus. While cybernetic models have been established by prior work carried out in bacterial systems, we show its applicability to more complex biological systems with a predefined goal. We have modeled eicosanoid, a well-characterized set of inflammatory lipids derived from arachidonic acid, metabolism in mouse bone marrow derived macrophage (BMDM) cells stimulated by Kdo2-Lipid A (KLA, a chemical analogue of Lipopolysaccharide found on the surface of bacterial cells) and adenosine triphosphate (ATP, a danger signal released in response to surrounding cell death) using cybernetic control variables. Here, the cybernetic goal is inflammation; the hallmark of inflammation is the expression of cytokines which act as autocrine signals to stimulate a pro-inflammatory response. Tumor necrosis factor (TNF)-α is an exemplary pro-inflammatory marker and can be designated as a cybernetic objective for modeling eicosanoid—prostaglandin (PG) and leukotriene (LK)—metabolism. Transcriptomic and lipidomic data for eicosanoid biosynthesis and conversion were obtained from the LIPID Maps database. We show that the cybernetic model captures the complex regulation of PG metabolism and provides a reliable description of PG formation using the treatment ATP stimulation. We then validated our model by predicting an independent data set, the PG response of KLA primed ATP stimulated BMDM cells.
The process of inflammation is mediated by the production of multiple cytokines, chemokines, and lipid mediators each of which contribute to specific individual objectives. For such complex processes in mammalian systems, a cybernetic objective based on a single protein/component may not be sufficient to capture all the biological processes thereby necessitating the use of multiple objectives. The choice of the objective function has been made by intuitive considerations in this thesis. If objectives are conjectured, an argument can be made for numerous alternatives. Since regulatory effects are estimated from unregulated kinetics, one encounters the risk of multiplicity in this regard giving rise to multiple models. The best model is of course that which is able to predict a comprehensive set of perturbations. Here, we have extended our above model to also capture the dynamics of LKs. We have used migration as a biological goal for LK using the chemoattractant CCL2 as a key representative molecule describing cell activation leading to an inflammatory response where a goal composed of multiple cybernetic objectives is warranted. Alternative model objectives included relating both branches of the eicosanoid metabolic network to the inflammatory cytokine TNF-α, as well as the simple maximization of all metabolic products such that each equally contributes to the inflammatory system outcome. We were again able to show that all three cybernetic objectives describing the LK and PG branches for eicosanoid metabolism capture the complex regulation and provide a reliable description of eicosanoid formation. We performed simulated drug and gene perturbation analyses on the system to identify differences between the models and propose additional experiments to select the best cybernetic model.
The advantage to using cybernetic modeling is in its ability to capture system behavior without the same level of detail required for these interactions as standard kinetic modeling. Given the complexity of mammalian systems, the cybernetic goal for mammalian cells may not be based solely on survival or growth but on specific context dependent cellular responses. In this thesis, we have laid the groundwork for the application of cybernetic modeling in complex mammalian systems through a specific example case of eicosanoid metabolism in BMDM cells, illustrated the case for multiple objectives, and highlighted the extensibility of the cybernetic framework to other complex biological systems.
(8065844), Jedadiah Floyd Burroughs. "Influence of Chemical and Physical Properties of Poorly-Ordered Silica on Reactivity and Rheology of Cementitious Materials." Thesis, 2019.
Знайти повний текст джерелаSilica fume is a widely used pozzolan in the concrete industry that has been shown to have numerous benefits for concrete including improved mechanical properties, refined pore structure, and densification of the interfacial transition zone between paste and aggregates. Traditionally, silica fume is used as a 5% to 10% replacement of cement; however, newer classes of higher strength concretes use silica fume contents of 30% or greater. At these high silica fume contents, many detrimental effects, such as poor workability and inconsistent strength development, become much more prominent.
In order to understand the fundamental reasons why high silica fume contents can have these detrimental effects on concrete mixtures, eight commercially available silica fumes were characterized for their physical and chemical properties. These included traditional properties such as density, particle size, and surface area. A non-traditional property, absorption capacity, was also determined. These properties or raw material characteristics were then related to the hydration and rheological behavior of pastes and concrete mixtures. Other tests were performed including isothermal calorimetry, which showed that each silica fume reacted differently than other silica fumes when exposed to the same reactive environment. Traditional hydration models for ordinary portland cement were expanded to include the effects that silica fumes have on water consumption, volumes of hydration products, and final degree of hydration.
As a result of this research, it was determined necessary to account for the volume and surface area of unhydrated cement and unreacted silica fume particles in water-starved mixture proportions. An adjustment factor was developed to more accurately apply the results from hydration modeling. By combining the results from hydration modeling with the surface area adjustments, an analytical model was developed to determine the thickness of paste (hydration products and capillary water) that surrounds all of the inert and unreacted particles in the system. This model, denoted as the “Paste Thickness Model,” was shown to be a strong predictor of compressive strength results. The results of this research suggest that increasing the paste thickness decreases the expected compressive strength of concretes at ages or states of hydration.
The rheological behavior of cement pastes containing silica fume was studied using a rotational rheometer. The Herschel-Bulkley model was fit to the rheological data to characterize the rheological behavior. A multilinear model was developed to relate the specific surface area of the silica fume, water content, and silica fume content to the Herschel-Bulkley rate index. The Herschel-Bulkley rate index is practically related to the ease at which the paste mixes. This multilinear model was shown to have strong predictive capability when used on randomly generated paste compositions.
Additionally, an analytical model was developed that defines a single parameter, idealized as the thickness of water surrounding each particle in the cementitious system. This model, denoted as the “Water Thickness Model,” incorporated the absorption capacity of silica fumes discovered during the characterization phase of this study and was shown to correlate strongly with the Herschel-Bulkley rate index. The Water Thickness Model demonstrates how small changes in water content can have a drastic effect on the rheology of low w/c or high silica fume content pastes due to the combined effects of surface area and absorption. The effect of additional water on higher w/c mixtures is significantly less.
(6411944), Francisco J. Montes Sr. "EFFECTS ON RHEOLOGY AND HYDRATION OF THE ADDITION OF CELLULOSE NANOCRYSTALS (CNC) IN PORTLAND CEMENT." Thesis, 2019.
Знайти повний текст джерелаAll the CNCs used were characterized in length, aspect ratio, and zeta potential to identify a definitive factor that governs the effect in the rheology of cement pastes. However, no definitive evidence was found that any of these characteristics dominated the measured effects.
The CNC dosage at which the maximum yield stress reduction occurred increased with the amount of water used in the paste preparation, which provides evidence of the dominance of the water to cement ratio in the rheological impact of CNC.
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Isothermal calorimetry showed that CNC cause concerning retardation effects in cement hydration. CNC slurries were then tested for sugars and other carbohydrates that could cause the aforementioned effect, then slurries were filtered, and impurities were detected in the filtrate, these impurities were quantified and characterized, however, the retardation appeared to be unaffected by the amount of the species detected, suggesting that the crystal chemistry, which is a consequence of the production method, is responsible of this retardation.
This work explores the benefits and drawbacks of the use of CNC in cement composites by individually approaching rheology and heat of hydration on a range of physical and chemical tests to build a better understanding of the observed effects.
Understanding the effect of CNCs on cement paste rheology can provide insights for future work of CNCs applications in cement composites.
Piper, Christine. "The impact of certification on women-owned construction firms in the United States." 2007. http://arrow.unisa.edu.au:8081/1959.8/46352.
Повний текст джерела(9154730), Russell S. Brayfield. "ELECTRODE EFFECTS ON ELECTRON EMISSION AND GAS BREAKDOWN FROM NANO TO MICROSCALE." Thesis, 2020.
Знайти повний текст джерела(10692402), Jorge Alfredo Rojas Rondan. "A BIM-based tool for formwork management in building projects." Thesis, 2021.
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