22 research outputs found
'One dark stormy night as the trian rattled on'
No full textYoung man travelling on a train with his babt. His wife lies dead in the baggage coach ahead. Other passengers [sic] are impatient with the baby's [sic] cries until the man tells his sad story.Laws, "NAB", 277 (ballad-like pieces); Mercer, "NH, 2, 1973, 10; "CFMJ", 7, 1979; "FH" Index: Gussie L. Davis, author, 5/12/23, 27/1/37, 3/5/39, 15/12/43, 30/7/53, "Variety Musical Cavalcade", 224, Spaeth, "Read 'Em...", 174-175; Randolf, IV, 163-165; Kennedy, "A Treasury of American Ballads", 343; Pound, "American Ballads and Songs", 5
On an Obstacle Problem for the Brakke Flow with a Generalized Right-Angle Boundary Condition
No full textWe study Brakke’s mean curvature flow with obstacles and with a right-angle boundary condition. Assuming that the obstacles have
-boundaries, we prove that a weak solution exists globally in time. To show the existence, we apply the phase-field method and thus investigate the singular limit of the Allen–Cahn equation with a forcing term and homogeneous Neumann bounday condition. We also construct sub- and supersolutions that correspond to the obstacles.The authors would like to thank the anonymous referees for their helpful suggestions that improved the preliminary version of the paper.he first author is supported by the APART-MINT Fellowship of the Austrian Acad-emy of Sciences ( \"OAW-APART-MINT grant 12114). This research was funded in part by the Aus-trian Science Fund (FWF) project 10.55776/F65 to the first author. The second author is supportedby JSPS KAKENHI grants JP20K14343, JP18H03670, JP23K03180, JP23H00085, and JP24K00531
Analysis of Pulsed Gas Metal Arc Welding (P-GMAW) Heat Input on UNS-S32101 Lean Duplex Stainless Steel
Get PDFabstract: This report presents the effects and analysis of the effects of Pulsed-Gas Metal Arc Welding's (P-GMAW) on Lean Duplex stainless steel. Although the welding of Duplex and Super Duplex Stainless steels have been well documented in both the laboratory and construction industry, the use of Lean Duplex has not. The purpose for conducting this research is to ensure that the correct Ferrite-Austenite phase balance along with the correct welding procedures are used in the creation of reactor cores for new construction nuclear power generation stations. In this project the effects of Lincoln Electrics ER-2209 GMAW wire are studied. Suggestions and improvements to the welding process are then proposed in order to increase the weldability, strength, gas selection, and ferrite count. The weldability will be measured using X-Ray photography in order to determine if any inclusions, lack of fusion, or voids are found post welding, along with welder feedback. The ferritic point count method in accordance with ASTM A562-08, is employed so that the amount of ferrite and austenite can be calculated in the same manor that is currently being used in industry. These will then be correlated to the tensile strength and impact toughness in the heat-affected zone (HAZ) of the weld based on the ASTM A923 testing method.Dissertation/ThesisM.S.Tech Technology 201
A Study On The Practical Application Of Repair Development Methods For Aerospace Components
Get PDFabstract: In the industry of manufacturing, each gas turbine engine component begins in a raw state such as bar stock and is routed through manufacturing processes to define its final form before being installed on the engine. What is the follow-up to this part? What happens when over time and usage it wears? Several factors have created a section of the manufacturing industry known as aftermarket to support the customer in their need for restoration and repair of their original product. Once a product has reached a wear factor or cycle limit that cannot be ignored, one of the options is to have it repaired to maintain use of the core. This research investigated the study into the creation and application of repair development methodology that can be utilized by current and new manufacturing engineers of the world. Those who have been in this field for some time will find the process thought provoking while the engineering students can develop a foundation of thinking to prepare for the common engineering problems they will be tasked to resolve. The examples, figures and tables are true issues of the industry though the data will have been changed due to proprietary factors. The results of the study reveals, under most scenarios, a solid process can be followed to proceed with the best options for repair based on the initial discrepancy. However, this methodology will not be a "catch-all" process but a guidance that will develop the proper thinking in evaluation of the repair options and the possible failure modes of each choice. As with any continuous improvement tool, further research is needed to test the applicability of this process in other fields.Dissertation/ThesisM.S. Technology 201
Feasibility and Manufacturing Considerations of Hemp Textile Fabric Utilized in Pre-Impregnated Composites
Get PDFabstract: This study investigates the fabrication and mechanical properties of semicontinuous, hemp fiber reinforced thermoset composites. This research determines if off-the-shelf refined woven hemp fabric is suitable as composite reinforcement using resin pre-impregnated method. Industrial hemp was chosen for its low cost, low resource input as a crop, supply chain from raw product to refined textile and biodegradability potential. Detail is placed on specimen fabrication considerations. Lab testing of tension and compression is conducted and optimization considerations are examined. The resulting composite is limited in mechanical properties as tested. This research shows it is possible to use woven hemp reinforcement in pre-impregnated processed composites, but optimization in mechanical properties is required to make the process commercially practical outside niche markets.Dissertation/ThesisM.S.Tech Engineering 201
Critical Evaluation and Optimization of a Hypocycloid Wiseman Engine
Get PDFabstract: In nearly all commercially successful internal combustion engine applications, the slider crank mechanism is used to convert the reciprocating motion of the piston into rotary motion. The hypocycloid mechanism, wherein the crankshaft is replaced with a novel gearing arrangement, is a viable alternative to the slider crank mechanism. The geared hypocycloid mechanism allows for linear motion of the connecting rod and provides a method for perfect balance with any number of cylinders including single cylinder applications. A variety of hypocycloid engine designs and research efforts have been undertaken and produced successful running prototypes. Wiseman Technologies, Inc provided one of these prototypes to this research effort. This two-cycle 30cc half crank hypocycloid engine has shown promise in several performance categories including balance and efficiency. To further investigate its potential a more thorough and scientific analysis was necessary and completed in this research effort. The major objective of the research effort was to critically evaluate and optimize the Wiseman prototype for maximum performance in balance, efficiency, and power output. A nearly identical slider crank engine was used extensively to establish baseline performance data and make comparisons. Specialized equipment and methods were designed and built to collect experimental data on both engines. Simulation and mathematical models validated by experimental data collection were used to better quantify performance improvements. Modifications to the Wiseman prototype engine improved balance by 20 to 50% (depending on direction) and increased peak power output by 24%.Dissertation/ThesisM.S.Tech Mechanical Engineering 201
The Application of Temper-Etch Inspection to Micromilled AISI 4340 Steel Specimen
No full textabstract: Micromachining has seen application growth in a variety of industries requiring a miniaturization of the machining process. Machining at the micro level generates different cutter/workpiece interactions, generating more localized temperature spikes in the part/sample, as suggested by multiple studies. Temper-etch inspection is a non-destructive test used to identify `grind burns' or localized over-heating in steel components. This research investigated the application of temper-etch inspection to micromachined steel. The tests were performed on AISI 4340 steel samples. Finding, indications of localized over-heating was the primary focus of the experiment. In addition, change in condition between the original and post-machining hardness in the machined slot bottom was investigated. The results revealed that, under the conditions of the experiment, no indications of localized over-heating were present. However, there was a change in hardness at the bottom of the machined slot compared to the rest of the sample. Further research is needed to test the applicability of temper-etch inspection to micromilled steel and to identify the source of the change in hardness.Dissertation/ThesisM.S.Tech Technology 201
New assumptions for stability analysis in elliptic optimal control problems
Get PDFThis paper is dedicated to the stability analysis of the optimal solutions of a control problem associated with a semilinear elliptic equation. The linear differential operator of the equation is neither monotone nor coercive due to the presence of a convection term. The control appears only linearly, or may not even appear explicitly in the objective functional. Under new assumptions, we prove Lipschitz stability of the optimal controls and associated states with respect to not only perturbations in the equation and the objective functional but also the Tikhonov regularization parameter.The first author was supported by MCIN/AEI/10.13039/501100011033/ under re-search project PID2020-114837GB-I00. The second and third authors were supported by the Aus-trian Science Foundation (FWF) under grant I457
Orientations and bijections for toroidal maps with prescribed face-degrees and essential girth
No full textInternational audienceWe present unified bijections for maps on the torus with control on the face-degrees and essential girth (girth of the periodic planar representation). A first step is to show that for d ≥ 3 every toroidal d-angulation of essential girth d can be endowed with a certain 'canonical' orientation (formulated as a weight-assignment on the half-edges). Using an adaptation of a construction by Bernardi and Chapuy, we can then derive a bijection between face-rooted toroidal d-angulations of essential girth d (with the condition that, apart from the root-face contour, no other closed walk of length d encloses the root-face) and a family of decorated unicellular maps. The orientations and bijections can then be generalized, for any d ≥ 1, to toroidal face-rooted maps of essential girth d with a root-face of degree d (and with the same root-face contour condition as for d-angulations), and they take a simpler form in the bipartite case, as a parity specialization. On the enumerative side we obtain explicit algebraic expressions for the generating functions of rooted essentially simple trian-gulations and bipartite quadrangulations on the torus. Our bijective constructions can be considered as toroidal counterparts of those obtained by Bernardi and the first author in the planar case, and they also build on ideas introduced by Despré, Gonçalves and the second author for essentially simple triangulations, of imposing a balancedness condition on the orientations in genus 1
