The effects of wear on abradable honeycomb labyrinth seals

This thesis reports on work undertaken to understand the effects, due to wear, on the performance of abradable honeycomb labyrinth seals. The phenomena studied are aerodynamic in nature and include compressible flow, turbulent flow, recirculation and separation at a range of pressure ratios from 1.20 up to 3.50. Four primary methods of investigation were used: experimental, numerical using CFD, numerical using theoretical derivations and numerical using established labyrinth seal specific computer codes. Effects of seal clearance, pressure ratio and tooth to groove location have been investigated with overall performance and inter-seal pressure distribution recorded experimentally and numerically for comparison. Worn experimental results, when compared to their unworn equivalent, recorded large increases in mass flow of up to 50% when the labyrinth teeth are located centrally in the groove. Significant performance enhancements were achieved through offsetting the teeth with respect to the groove, particularly in an upstream sense. There was a marked deterioration with the labyrinth teeth located at the groove exit. Inter-seal pressure distributions showed that the first and final teeth did most of the work achieving significantly larger pressure drops which goes against current seal understanding of increasing pressure drop through the seal. Numerical work was undertaken to further investigate these effects. However, due to the complex 3-D geometry of an abradable honeycomb labyrinth seal a 2-D simplification technique was developed to speed up the investigative process. Using this technique CFD was found capable of replicating the experimental data regarding overall seal performance and inter-seal pressure distributions. The pressure on the final tooth proved to be the hardest experimental data to recreate using CFD, particularly at high pressure ratios when shocks are likely to form. Further numerical work was undertaken using computer codes and theoretical derivations. This work proved that the understanding of the seal loss coefficients used by both methods was not adequate for the current study with the experimental data recreated least successfully. Suggestions are given for enhancement of seal design, including axial location and seal computational routines, which will limit the impact of a 1.5% increase in operational cost that is likely to accrue from seal deterioration.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Synthesis And Applications Of Symmetric Building Blocks In Supramolecular, Single-Stranded, And Double-Stranded Polymers

In this study, supramolecular polymers from carbamates are studied. A number of three-fold symmetric carbamates have been synthesized, characterized and their self-assembly structure are studied. The lamellar structures are detected and compared by using their melting points, NMR and FT-IR spectroscopy, and single crystal X-ray diffraction. The hydrogen-bond networks of each compound in crystalline state are examined. A new hydrogen bonded network self-assembles under mild conditions from benzene-1,3,5-triyl tris(butyl carbamate) (2), benzene-1,3,5-triyl tris(pentyl carbamate) (3), benzene-1,3,5-triyl tris(hexyl carbamate) (4), and benzene-1,3,5-triyl tris(heptyl carbamate) (5). One of the carbonyl groups in the molecules 2-4 does not form a C=O⋯H–N hydrogen bond in the sheet-like structure. Three different types of hydrogen bonding sites are observed. Although the building blocks only differ in the number of carbons in their side chains, this 2D unsaturated hydrogen bonded network is different from the saturated one which is self-assembled from benzene-1,3,5-triyl tris(propyl carbamate) 1. For compounds 2-5, the odd-even effect is also observed in terms of melting point, as well as the dihedral angle between the aromatic core and the arm with an oversaturated hydrogen bond. The inverted carbamates 7-11 are also synthesized and studied. An organic gel is found in triheptyl Nʹ,Nʹʹ,Nʹʹʹ-benzene-1,3,5-tricarbamate 11 with a concentration of 20 g/L (2.6 Ã10-2 M) in n-dodecane. A mirror-symmetric building block for linear polymer is designed. 3,4-Di(furan-2-yl)cyclobutane-1,2-dicarboxylic acid (12) is synthesized from 3-(2-furyl)acrylic acid (12ʹ) through a solid-state [2+2] photocycloaddition by UV-A irradiation in quantitative yield. This building block molecule is derived from furfural and malonic acid. Thus, a novel 100% bio-based monomer has been successfully synthesized. For the first time, the single crystal is obtained in MeOH/DCM at room temperature. The thermal stability and acidic resistance of the cyclobutane ring of this building block is tested by thermal gravimetric analysis (GTA) and acid treatment. As a proof-of-concept, the condensation of 12 and 1,5-pentanediol is evaluated in this study. MS and NMR spectra of the product prove the formation of the target polymer. A series of cyclic C2-symmetric building blocks for double-stranded polymers are designed. Our goal is to synthesize a linear polymer with double-stranded chains. The two strands are anchored by a C-C single bond so that the width is only extended by one covalent bond while the strength of the chain is enhanced. To achieve this polymer, a three-step strategy has been designed. The first step is to synthesize a cyclic monomer with a C=C bond at each end of the molecule. The second step is to apply intermolecular interactions for self-assembling the monomer. When desirable crystalline packing is obtained, the third step is to generate cyclobutane rings between each neighboring C=C bond by solid-state [2+2] photocycloaddition to form the double-stranded polymer. A series of lactone monomers have been successfully synthesized and their structures are confirmed by NMR spectroscopy. (3Z,14Z)-1,6,12,17-tetraoxacyclodocosa-3,14-diene-2,5,13,16-tetraone (17) is synthesized from maleic anhydride and 1,5-pentanediol. Then isomerization of compound 17 afford (3E,14E)-1,6,12,17-tetraoxacyclodocosa-3,14-diene-2,5,13,16-tetraone (18). Crystalline structures of these two compounds are analyzed by SCXRD and their photoreactivity is examined. The photopolymerization of 17 is supported by IR and solid state 13C NMR spectra

Technology for the Future: In-Space Technology Experiments Program, part 1

The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiment Program (In-STEP) 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part one of two parts and is the executive summary and experiment description. The executive summary portion contains keynote addresses, strategic planning information, and the critical technology needs summaries for each theme. The experiment description portion contains brief overviews of the objectives, technology needs and backgrounds, descriptions, and development schedules for current industry, university, and NASA space flight technology experiments

Retrospective Analysis of Rubber Injector Molding Design Technologies

Artificial Intelligence is fundamentally a product of reverse engineering, emphasizing the importance of understanding its principles. It highlights the necessity of regulating and containing this process while recognizing it as a distinct science with numerous subdivisions, including reverse engineering in materials, design, geometry, robotics, and more, rather than merely viewing it as a duplicative technique. In manufacturing and production technologies, reverse engineering assists design engineers in rapidly obtaining critical information about benchmark products. Within this context, the initial aim of this work was to provide research-based statistics for designing a rubber mold without access to a drafted sketch of the rubber product. Using a 3D-scanned model of a rubber sample, the product was scanned, and the scanned image was inspected. It became evident that the sample contained multiple centroids for the circular cylinders that contributed to the product's seemingly symmetric shape. However, a single centroid for these cylinders would have been a sufficient condition for symmetry. This discrepancy revealed by the scanned model shifted the research focus from a methodical analysis to a qualitative exploration of challenges. Understanding the ingredients and formulation of the rubber compound became essential for producing a reliable initial design sketch.The elastomer's complex behavior under extreme heat and compression during the curing process introduces significant challenges in the rubber component's geometry. This thesis investigates unwanted geometric changes in rubber components during the curing process. Ultimately, it examines the impact of injection molding and rubber compounds on the components' geometry. The study also delves into reverse engineering techniques for rubber products, identifies influential factors, and provides practical guidelines for designing a reversely engineered sketch.This project was commissioned by Ravelast Polymers and carried out in collaboration with company experts specializing in polymer and chemical industrie

NASA Tech Briefs, September 1990

Topics covered include: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

NASA Tech Briefs, February 1993

Topics include: Communication Technology; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Topical scientific researches into resource-saving technologies of mineral mining and processing

Table of contents Preface . 5 Malanchuk Z.R., Soroka V.S., Lahodniuk O.A., Marchuk M.M. Physical-mechanical and technological features of amber extraction in the Rivne-Volyn region of Ukraine . 6 Moshynskyi, V.S., Korniyenko V.Ya., Khrystyuk A.O., Solvar L.M. Research of energy effective parameters of the process of hydro mechanical extraction of amber from sandy deposits . 24 Mohamed Tafsir Diallo, Mamadou Oury Fatoumata Diallo Tidal Park – Modeling and Control Strategy . 38 Savina N.B., Malanchuk L.O., Ignatiuk I.Z., Moshchych S.Z. Institutional basis and trends of management of the use of the subsoil in Ukraine . 51 Dedelyanova Kr.Y. Column flotation machine – innovative aeration, vibra-tory – acoustic and technological researches . 60 Makarenko V.D., Manhura A.M., Lartseva I.I., Manhura S.I. Magnetic field on asphalt, resin, paraffin and salt deposits 79 Krzysztof Tomiczek The problem of beds stability in the conditions of undermining higher deposited beds in the context of selected analytical solutions . 95 Safonyk A.P., Koziar M.M., Martyniuk P.M., Fylypchuk V.L. Management of pollution - purification system for mining plants . 117 Marinela Panayotova, Vladko Panayotov Recent developments in the flotation of sulfide ores of base metals - bioflotation . 130 Remez N., Dychko A., Bronytskyi V., Kraychuk S. Simulation of shock waves from explosion of mixture explosive charges . 149 Melodi M.M. Akande V.O. Analysis of productivity and technical efficiency in granite aggregate production in selected quarries in south-western, Nigeria . 166 Doroshenko Ya.V., Karpash O.M., Rybitskyi I.V. Investigation of dispersed contaminates influence on the hydraulic energy consumption of elements of gas pipeline systems with complex geometry . 182 Skipochka S.I., Krukovskyi O.P., Krukovska V.V., Palamarchuk T.A. Features of methane emission in coal mines at high speed longwall face advance 208 Daouda Keita, Valery Pozdnyakov Statistical analysis of experimental data on the indices of operation of the loading units of the bauxite compa-ny of Guinea (CBG) . 226 Yevhenii Malanchuk, Sergiy Stets, Ruslan Zhomyruk, Andriy Stets Modeling of the process of mining of zeolite-smectite tuffs by hydro-well method . 244 Samusia V. I., Kyrychenko Y. О., Cheberiachko I. M., Trofymova, O. P. Development of experimental methods to study heterogenic flows in the context of hydraulic hoisting design . 260 Makarenko V.D., Kharchenko M.O., Manhura A.M., Petrash O.V. Magnetic treatment of production fluid with high content of asphalt-resin-paraffin deposits . 268 Kovshun N.E., Ignatiuk I.Z., Moshchych S.Z. Malanchuk L.O. Innovative model of development of fuel and energy complex of Ukraine 279 Bondarenko А.O., Ostapchuk O.V. Design and implementation of a jet pump dredge . 296 Sotskov V.O., Dereviahina N.I. Research of dependencies of stope stress-strain state change under various conditions of partial stowing of developed space . 305 Sakhno S., Liulchenko Y., Chyrva T., Pischikova O. Determination of bear-ing capacity and calculation of the gain of the damaged span of a railway overpass by the finite element method . 326 Melodi М.М., Ojulari M.K. Oluwafemi V.I. Economic and environmental impacts of artisanal gold mining on near-by community of Sauka-Kahuta, Nigeria . 340 Kruchkov A.I., Besarabets Y.J., Yevtieieva L.I. Energy saving modes of excavators type power shovel . 353 Hryhorash M.V., Kuzminskyi V.P., Ovchinnikova O.V., Kukhar V.Yu. Energy saving through quality of technical water: new types of mechanical screen filters for various links of water treatment . 369 Didenko M. The modeling of the interaction of rock mass and compliant lining while it is expanded . 394 Makarenko V.D., Liashenko A.V. Complex approach to research and selection of hydrocarbon solvents for asphaltene-resin-paraffin-hydrate deposits control . 408 Mykhailovska O.V., Zotsenko M.L. Investigation of the oscillations amplitudes bases and foundations of the forming machine . 417 Inkin O.V., Puhach A.M., Dereviahina N.I. Physical-chemical and technological parameters of improving profitability of underground coal burning . 42

Latest Advancements in Micro Nano Molding Technologies – Process Developments and Optimization, Materials, Applications, Key Enabling Technologies

Micro- and nano-molding technologies are continuously being developed due to enduring trends like increasing miniaturization and higher functional integration of products, devices, and systems. Furthermore, with the introduction of higher performance polymers, feedstocks, and composites, new opportunities in terms of material properties can be exploited, and, consequently, more micro-products and micro/nano-structured surfaces are currently being designed and manufactured.Innovations in micro- and nano-molding techniques are seen in the different processes employed in production (injection molding, micro injection molding, etc.); on the use of new and functional materials; for an ever-increasing number of applications (health-care devices, micro-implants, mobility, and communications products, optical elements, micro-electromechanical systems, sensors, etc.); in several key enabling technologies that support the successful realization of micro and nano molding processes (micro- and nano-tooling technologies, process monitoring techniques, micro- and nanometrology methods for quality control, simulation, etc.) and their integration into new manufacturing process chains.This Special Issue reprint showcases research papers and review articles that focus on the latest developments in micro-manufacturing and key enabling technologies for the production of both micro-products and micro-structured surfaces

Experimental and Computational Studies on Cryogenic Turboexpander

The expansion turbine constitutes the most critical component of a large number of cryogenic process plants – air separation units, helium and hydrogen liquefiers, and low temperature refrigerators. A medium or large cryogenic system needs many components, compressor, heat exchanger, expansion turbine, instrumentation, vacuum vessel etc. At present most of these process plants operate at medium or low pressure due to its inherent advantages. A basic component which is essential for these processes is the turboexpander. The theory of small turboexpanders and their design method are not fully standardised. Although several companies around the world manufacture and sell turboexpanders, the technology is not available in open literature. To address to this problem, a modest attempt has been made at NIT, Rourkela to understand, standardise and document the design, fabrication and testing procedure of cryogenic turboexpanders. The research programme has two major objectives – ⇒ A clear understanding of the thermodynamic scenario though modelling, that will help in determination of blade profile, and prediction of its performance for a given speed and size. ⇒ To build and record in open literature a complete turbine system