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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The time-temperature-sensitization behavior of alloy 800 as determined by the electrochemical potentiokinetic reactivation test and the modified strauss test

Edgemon, Glenn Leon 12 1900 (has links)
No description available.
2

Damage rate approaches for nickel-base superalloys

Reynolds, Gary James 12 1900 (has links)
No description available.
3

Go tell it on the mountain a history of Narrow Ridge Earth Literacy Center, 1970-2004 /

Smith, Christopher T. January 2009 (has links) (PDF)
Honors project (B.A.) -- Carson-Newman College, 2009. / Project advisor: Dr. Beth Vanlandingham. Includes bibliographical references (p. 40-41).
4

Measurement of stress and defects in mild steel and nickel by magnetoacoustic emission.

January 1994 (has links)
by Lo, Chi Ho Chester. / Title also in Chinese characters. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 159-163). / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.iv / List of Figures --- p.vii / List of Tables --- p.xii / Chapter Chapter One --- Introduction --- p.1 / Chapter Chapter Two --- Domain Theory --- p.8 / Chapter 2.1 --- Energies in Magnetic Domain Structure --- p.8 / Chapter 2.2 --- Domains in Iron and Nickel --- p.13 / Chapter 2.3 --- Magnetization Process --- p.15 / Chapter 2.4 --- Effect of Applied Stress --- p.19 / Chapter Chapter Three --- Magnetoacoustic Emission --- p.25 / Chapter 3.1 --- Models of MAE --- p.25 / Chapter 3.1.1 --- Discontinuous Wall Motion --- p.25 / Chapter 3.1.2 --- Displacement Model --- p.28 / Chapter 3.1.3 --- DW Creation and Annihilation --- p.30 / Chapter 3.1.4 --- Combined Model of MAE --- p.31 / Chapter 3.2 --- MAE and Magnetic Induction --- p.34 / Chapter 3.2.1 --- Eddy Current Shielding --- p.34 / Chapter 3.2.2 --- Magnetic Reluctance Calculation --- p.35 / Chapter Chapter Four --- Experiments / Chapter 4.1 --- Instrumentation --- p.40 / Chapter 4.1.1 --- Introduction --- p.40 / Chapter 4.1.2 --- Basic Setup --- p.41 / Chapter 4.1.3 --- Arrangement for Stress Measurement --- p.46 / Chapter 4.1.4 --- Specimen Preparation --- p.43 / Chapter 4.2 --- Methodology / Chapter 4.2.1 --- The Fundamental Study of MAE --- p.53 / Chapter 4.2.1.1 --- Effects of Demagnetizing and Stray Fields on MAE --- p.53 / Chapter 4.2.1.2 --- Dependence of MAE on Frequency of Applied Field --- p.55 / Chapter 4.2.1.3 --- Dependence of MAE on Specimen Thickness and Width --- p.55 / Chapter 4.2.2 --- Stress Measurement --- p.58 / Chapter 4.2.2.1 --- Effect of Uniaxial Stress on MAE --- p.58 / Chapter 4.2.2.2 --- Effect of Biaxial Stresses on MAE --- p.58 / Chapter 4.2.3 --- Defect Detection --- p.60 / Chapter 4.2.3.1 --- Nickel --- p.60 / Chapter 4.2.3.2 --- Mild Steel --- p.61 / Chapter Chapter Five --- Results and Discussion / Chapter 5.1 --- Effects of Demagnetizing and Stray Fields on MAE --- p.63 / Chapter 5.1.1 --- MAE Profiles --- p.63 / Chapter 5.1.2 --- Magnetic Reluctance Calculation --- p.68 / Chapter 5.1.3 --- Effect of Annealing --- p.74 / Chapter 5.1.3.1 --- Experimental Results --- p.74 / Chapter 5.1.3.2 --- Discussion --- p.77 / Chapter 5.1.3.3 --- Magnetic Reluctance Calculation --- p.78 / Chapter 5.2 --- Dependence of MAE on Frequency of Applied Field --- p.83 / Chapter 5.2.1 --- Experimental Results --- p.83 / Chapter 5.2.2 --- Theoretical Consideration --- p.88 / Chapter 5.3 --- Dependence of MAE on Specimen Thickness and Width --- p.96 / Chapter 5.3.1 --- Experimental Results --- p.96 / Chapter 5.3.2 --- Theoretical Consideration --- p.99 / Chapter 5.4 --- Effects of Uniaxial and Biaxial Stresses on MAE --- p.107 / Chapter 5.4.1 --- Effect of Uniaxial Stress --- p.107 / Chapter 5.4.1.1 --- Experimental Results --- p.107 / Chapter 5.4.1.2 --- Discussion --- p.116 / Chapter 5.4.2 --- Effect of Biaxial Stresses --- p.120 / Chapter 5.4.2.1 --- Study on Mild Steel Specimen --- p.120 / Chapter 5.4.2.2 --- Study on Nickel Specimen --- p.132 / Chapter 5.5 --- Defect Detection by MAE --- p.137 / Chapter 5.5.1 --- Study on Nickel Specimen --- p.137 / Chapter 5.5.1.1 --- Experimental Results --- p.137 / Chapter 5.5.1.2 --- Discussion --- p.140 / Chapter 5.5.2 --- Study on Mild Steel Specimen --- p.142 / Chapter 5.5.2.1 --- Experimental Results --- p.142 / Chapter 5.5.2.2 --- Discussion --- p.151 / Chapter Chapter Six --- Conclusions and Suggestions for Further Studies --- p.153 / References --- p.159
5

Design and synthesis of wide bite angle phosphacyclic ligands

Gillespie, Jason A. January 2012 (has links)
By examining structure activity relationships for a given catalytic reaction it is possible to discover what ligand features and parameters lead to stable and highly active/selective catalyst systems. With this knowledge in hand it may be possible to rationally design next generation ligands and catalysts to affect improved substrate transformations, with higher selectivities and faster reaction times. The success of Burk's DuPhos ligands in asymmetric hydrogenation demonstrated that chiral phosphacycles can be a potent source of chiral induction, whilst in a similar vein the work of van Leeuwen and Kamer established the wide bite angle xanthene based ligands as excellent catalysts in a range of reactions including hydroformylation. In a preliminary study with Osborne they showed that combining these wide bite angle ligand backbones with Burk's phospholane moieties led to a new powerful ligand in asymmetric allylic substitution. To examine the potential of combining these two ligand features further we designed and synthesised nine new C2-symmetric bidentate wide bite angle bisphosphacyclic ligands, featuring phosphetane, phospholane or diazaphospholane rings, aiming at a wide diversity of steric and electronic properties. The application of these ligands as chiral auxiliaries in transition metal catalysed reactions, including; hydrogenation, hydrocyanation, hydroformylation and allylic alkylation has been investigated. Good to excellent enantioselectivities were observed in all reactions, with maximum ee's of 92.5% observed in hydrogenation, using N-(3,4-dihydro-1-napthalenyl)-acetamide as substrate, and of 96.2% in the alkylation of 1,3-diphenyl-2-propenyl acetate.
6

Reductive Binding of C‒O and Nitro Substrates at a Pyrazolate-Bridged Preorganized Dinickel Scaffold

Kothe, Thomas 03 November 2021 (has links)
No description available.
7

Pyrolysis of Municipal Sewage Sludge to get a phosphorus rich char residue for soil improvement / Pyrolys av kommunalt avloppsslam för att framställa ett fosforrikt kol för jordförbättring

Shamim, Shahin January 2023 (has links)
Sewage sludge is a byproduct of wastewater treatment plants. It is a kind of waste. however, it contains several valuable nutrients like phosphorous and nitrogen that are used to rich the soil as a fertilizer compound. On the other hand, it contains some harmful and toxic compounds such as pathogens, pharmaceuticals, Polychlorinated biphenyl (PCBs), Polycyclic aromatic hydrocarbons (PAHs), endocrine-disruption, hormones, and heavy metals which are contaminants and pollutants in the environment. Pyrolysis is a way to treat these contaminants and reduces the quantity of heavy metals and removes pathogens. This project derives to pyrolysis the sewage sludge at three different temperatures 500°C,700°C, and 900°C, and evaluates the result according to the remained quantities of heavy metals and phosphorous. Each experiment was repeated three times. Then, the samples weighted and analyzed by bomb calorimeter, microwave digestion, and MP-AES. Bomb calorimetry was used for measuring the heating value to compare the remaining heating value in the samples to the raw sewage sludge. The microwave digestion system was used for chemical processing of the samples in order to break down the samples to liquid form and then the concentration of elements such as Cd, Co, Cr, Cu, Ni, Mn, Zn, Pb, and P were measured by MP-AES. The results were gathered and compared with the Regulation by European, Union, (DirectiveE86/278/EEC), and Regulation by Swedish law, (Regulation1998:994). The raw sewage sludge was delivered from Borås wastewater treatment unit after digestion in an anaerobic fermentation process. It contained about 74% water which was dried in an oven at 105°C. The results show that Cd and Co were removed from the sewage sludge and the most amount of phosphorus remained in the resulting char. The results show that the quantity of phosphorus was almost the same between 500°C-700°C. The data shows that the amount of Pb was reduced by increasing the temperature of the pyrolysis reaction. The heating value in the char was extremely close to each other in the different range of reaction temperatures between 500°C to 900°C.
8

Crack detection in Waspaloy during the DirectEnergy Deposition Laser Beam Wire Additive Manufacturing process : using Acoustic Emissions and Hierarchical clustering / Crack detection in Waspaloy during the DirectEnergy Deposition Laser Beam Wire Additive Manufacturing process using Acoustic Emissions and Hierarchical clustering

Drysdale, Morgan January 2024 (has links)
Metal additive manufacturing is an important tool for the creation of cost effective and environmentally friendly components for the future of the aerospace industry. Newly developed methods such as Direct Energy Deposition, Laser Beam Wire (DEDLB/w) have the potential to quickly and effciently manufacture aircraft engine components of high quality when utilising the correct set of process parameters. Establishing these parameters is a challenging task as product defects can be diffcult to detect and localise during the DEDLB/w process. This thesis explores the possibility of detecting crack type defects during the additive manufacturing of Nickel-Based Superalloy components using in process acoustic emission inspection and hierarchical clustering to evaluate DEDLB/w process parameter sets. After observing numerous material depositions made using DEDLB/w, crack-like signals were observed and clustered using features derived from Acoustic Emission (AE) data. The results were then evaluated and validated using X-Ray and X-Ray Computed Tomography (µCT) inspection. Crack-like acoustic emissions were recorded from depositions in which cracks were later found using X-rayand µCT inspection, and these emissions were successfully clustered over multiple depositions using statistical analysis and agglomerative clustering.

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