Liquid cooling solutions for rotating permanent magnet synchronous machines

In the design of electrical machines, efficiency improvements have become very important. However, there are at least two significant cases in which the compactness of electrical machines is critical and the tolerance of extremely high losses is valued: vehicle traction, where very high torque density is desired at least temporarily; and direct-drive wind turbine generators, whose mass should be acceptably low. As ever higher torque density and ever more compact electrical machines are developed for these purposes, thermal issues, i.e. avoidance of over-temperatures and damage in conditions of high heat losses, are becoming of utmost importance. The excessive temperatures of critical machine components, such as insulation and permanent magnets, easily cause failures of the whole electrical equipment. In electrical machines with excitation systems based on permanent magnets, special attention must be paid to the rotor temperature because of the temperature-sensitive properties of permanent magnets. The allowable temperature of NdFeB magnets is usually significantly less than 150 ˚C. The practical problem is that the part of the machine where the permanent magnets are located should stay cooler than the copper windings, which can easily tolerate temperatures of 155 ˚C or 180 ˚C. Therefore, new cooling solutions should be developed in order to cool permanent magnet electrical machines with high torque density and because of it with high concentrated losses in stators. In this doctoral dissertation, direct and indirect liquid cooling techniques for permanent magnet synchronous electrical machines (PMSM) with high torque density are presented and discussed. The aim of this research is to analyse thermal behaviours of the machines using the most applicable and accurate thermal analysis methods and to propose new, practical machine designs based on these analyses. The Computational Fluid Dynamics (CFD) thermal simulations of the heat transfer inside the machines and lumped parameter thermal network (LPTN) simulations both presented herein are used for the analyses. Detailed descriptions of the simulated thermal models are also presented. Most of the theoretical considerations and simulations have been verified via experimental measurements on a copper tooth-coil (motorette) and on various prototypes of electrical machines. The indirect liquid cooling systems of a 100 kW axial flux (AF) PMSM and a 110 kW radial flux (RF) PMSM are analysed here by means of simplified 3D CFD conjugate thermal models of the parts of both machines. In terms of results, a significant temperature drop of 40 ̊C in the stator winding and 28 ̊C in the rotor of the AF PMSM was achieved with the addition of highly thermally conductive materials into the machine: copper bars inserted in the teeth, and potting material around the end windings. In the RF PMSM, the potting material resulted in a temperature decrease of 6 ̊C in the stator winding, and in a decrease of 10 ̊C in the rotor embedded-permanentmagnets. Two types of unique direct liquid cooling systems for low power machines are analysed herein to demonstrate the effectiveness of the cooling systems in conditions of highly concentrated heat losses. LPTN analysis and CFD thermal analysis (the latter being particularly useful for unique design) were applied to simulate the temperature distribution within the machine models. Oil-immersion cooling provided good cooling capability for a 26.6 kW PMSM of a hybrid vehicle. A direct liquid cooling system for the copper winding with inner stainless steel tubes was designed for an 8 MW directdrive PM synchronous generator. The design principles of this cooling solution are described in detail in this thesis. The thermal analyses demonstrate that the stator winding and the rotor magnet temperatures are kept significantly below their critical temperatures with demineralized water flow. A comparison study of the coolant agents indicates that propylene glycol is more effective than ethylene glycol in arctic conditions.

Surface studies of limestones and dolostones : characterisation using various techniques and batch dissolution experiments with hydrochloric acid solutions

In this thesis, stepwise titration with hydrochloric acid was used to obtain chemical reactivities and dissolution rates of ground limestones and dolostones of varying geological backgrounds (sedimentary, metamorphic or magmatic). Two different ways of conducting the calculations were used: 1) a first order mathematical model was used to calculate extrapolated initial reactivities (and dissolution rates) at pH 4, and 2) a second order mathematical model was used to acquire integrated mean specific chemical reaction constants (and dissolution rates) at pH 5. The calculations of the reactivities and dissolution rates were based on rate of change of pH and particle size distributions of the sample powders obtained by laser diffraction. The initial dissolution rates at pH 4 were repeatedly higher than previously reported literature values, whereas the dissolution rates at pH 5 were consistent with former observations. Reactivities and dissolution rates varied substantially for dolostones, whereas for limestones and calcareous rocks, the variation can be primarily explained by relatively large sample standard deviations. A list of the dolostone samples in a decreasing order of initial reactivity at pH 4 is: 1) metamorphic dolostones with calcite/dolomite ratio higher than about 6% 2) sedimentary dolostones without calcite 3) metamorphic dolostones with calcite/dolomite ratio lower than about 6% The reactivities and dissolution rates were accompanied by a wide range of experimental techniques to characterise the samples, to reveal how different rocks changed during the dissolution process, and to find out which factors had an influence on their chemical reactivities. An emphasis was put on chemical and morphological changes taking place at the surfaces of the particles via X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). Supporting chemical information was obtained with X-Ray Fluorescence (XRF) measurements of the samples, and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) measurements of the solutions used in the reactivity experiments. Information on mineral (modal) compositions and their occurrence was provided by X-Ray Diffraction (XRD), Energy Dispersive X-ray analysis (EDX) and studying thin sections with a petrographic microscope. BET (Brunauer, Emmet, Teller) surface areas were determined from nitrogen physisorption data. Factors increasing chemical reactivity of dolostones and calcareous rocks were found to be sedimentary origin, higher calcite concentration and smaller quartz concentration. Also, it is assumed that finer grain size and larger BET surface areas increase the reactivity although no certain correlation was found in this thesis. Atomic concentrations did not correlate with the reactivities. Sedimentary dolostones, unlike metamorphic ones, were found to have porous surface structures after dissolution. In addition, conventional (XPS) and synchrotron based (HRXPS) X-ray Photoelectron Spectroscopy were used to study bonding environments on calcite and dolomite surfaces. Both samples are insulators, which is why neutralisation measures such as electron flood gun and a conductive mask were used. Surface core level shifts of 0.7 ± 0.1 eV for Ca 2p spectrum of calcite and 0.75 ± 0.05 eV for Mg 2p and Ca 3s spectra of dolomite were obtained. Some satellite features of Ca 2p, C 1s and O 1s spectra have been suggested to be bulk plasmons. The origin of carbide bonds was suggested to be beam assisted interaction with hydrocarbons found on the surface. The results presented in this thesis are of particular importance for choosing raw materials for wet Flue Gas Desulphurisation (FGD) and construction industry. Wet FGD benefits from high reactivity, whereas construction industry can take advantage of slow reactivity of carbonate rocks often used in the facades of fine buildings. Information on chemical bonding environments may help to create more accurate models for water-rock interactions of carbonates.

Mathematical modeling of electro-rotation spectra of small particles in liquid solutions: Application to human erythrocyte aggregates

Electro-rotation can be used to determine the dielectric properties of cells, as well as to observe dynamic changes in both dielectric and morphological properties. Suspended biological cells and particles respond to alternating-field polarization by moving, deforming or rotating. While in linearly polarized alternating fields the particles are oriented along their axis of highest polarizability, in circularly polarized fields the axis of lowest polarizability aligns perpendicular to the plane of field rotation. Ellipsoidal models for cells are frequently applied, which include, beside sphere-shaped cells, also the limiting cases of rods and disks. Human erythrocyte cells, due to their particular shape, hardly resemble an ellipsoid. The additional effect of rouleaux formation with different numbers of aggregations suggests a model of circular cylinders of variable length. In the present study, the induced dipole moment of short cylinders was calculated and applied to rouleaux of human erythrocytes, which move freely in a suspending conductive medium under the effect of a rotating external field. Electro-rotation torque spectra are calculated for such aggregations of different length. Both the maximum rotation speeds and the peak frequencies of the torque are found to depend clearly on the size of the rouleaux. While the rotation speed grows with rouleaux length, the field frequency nup is lowest for the largest cell aggregations where the torque shows a maximum.

Desmin: molecular interactions and putative functions of the muscle intermediate filament protein

Desmin is the intermediate filament (IF) protein occurring exclusively in muscle and endothelial cells. There are other IF proteins in muscle such as nestin, peripherin, and vimentin, besides the ubiquitous lamins, but they are not unique to muscle. Desmin was purified in 1977, the desmin gene was characterized in 1989, and knock-out animals were generated in 1996. Several isoforms have been described. Desmin IFs are present throughout smooth, cardiac and skeletal muscle cells, but can be more concentrated in some particular structures, such as dense bodies, around the nuclei, around the Z-line or in costameres. Desmin is up-regulated in muscle-derived cellular adaptations, including conductive fibers in the heart, electric organs, some myopathies, and experimental treatments with drugs that induce muscle degeneration, like phorbol esters. Many molecules have been reported to associate with desmin, such as other IF proteins (including members of the membrane dystroglycan complex), nebulin, the actin and tubulin binding protein plectin, the molecular motor dynein, the gene regulatory protein MyoD, DNA, the chaperone alphaB-crystallin, and proteases such as calpain and caspase. Desmin has an important medical role, since it is used as a marker of tumors' origin. More recently, several myopathies have been described, with accumulation of desmin deposits. Yet, after almost 30 years since its identification, the function of desmin is still unclear. Suggested functions include myofibrillogenesis, mechanical support for the muscle, mitochondrial localization, gene expression regulation, and intracellular signaling. This review focuses on the biochemical interactions of desmin, with a discussion of its putative functions.

Replacing Copper with New Carbon Nanomaterials in Electrical Machine Windings

Electrical machines have significant improvement potential. Nevertheless, the field is characterized by incremental innovations. Admittedly, steady improvement has been achieved, but no breakthrough development. Radical development in the field would require the introduction of new elements, such that may change the whole electrical machine industry system. Recent technological advancements in nanomaterials have opened up new horizons for the macroscopic application of carbon nanotube (CNT) fibres. With values of 100 MS/m measured on individual CNTs, CNT fibre materials hold promise for conductivities far beyond those of metals. Highly conductive, lightweight and strong CNT yarn is finally within reach; it could replace copper as a potentially better winding material. Although not yet providing low resistivity, the newest CNT yarn offers attractive perspectives for accelerated efficiency improvement of electrical machines. In this article, the potential for using new CNT materials to replace copper in machine windings is introduced. It does so, firstly, by describing the environment for a change that could revolutionize the industry and, secondly, by presenting the breakthrough results of a prototype construction. In the test motor, which is to our knowledge the first in its kind, the presently most electrically conductive carbon nanotube yarn replaces usual copper in the windings.

Musiikin poliittinen ekonomia tuoreen tutkimuksen kohteena

Kirjallisuusarvostelu

Turkic Manuscript in Kazakh-Chaghatai (MS Or.49)

A coverless notebook, written in two columns in ink in various colours. Rhymed verse, written by an author from the Temir-Bolat clan. He mentions the following names: Samarkand, Bukhara, Urgench, Tashkent, Kokand, the Karakalpaks, and the Turkmens. It the opening notes there are names of persons.

Synthesis and characterization of nanoperforated metal oxide thin films

For advanced devices in the application fields of data storage, solar cell and biosensing, one of the major challenges to achieve high efficiency is the fabrication of nanopatterned metal oxide surfaces. Such surfaces often require both precise structure at the nanometer scale and controllable patterned structure at the macro scale. Nowadays, the dominating candidates to fabricate nanopatterned surfaces are the lithographic technique and block-copolymer masks, most of which are unfortunately costly and inefficient. An alternative bottom-up approach, which involves organic/inorganic self-assembly and dip-coating deposition, has been studied intensively in recent years and has proven to be an effective technique for the fabrication of nanoperforated metal oxide thin films. The overall objective of this work was to optimize the synthesis conditions of nanoperforated TiO2 (NP-TiO2) thin films, especially to be compatible with mixed metal oxide systems. Another goal was to develop fabrication and processing of NP-TiO2 thin films towards largescale production and seek new applications for solar cells and biosensing. Besides the traditional dip-coating and drop-casting methods, inkjet printing was used to prepare thin films of metal oxides, with the advantage of depositing the ink onto target areas, further enabling cost-effective fabrication of micro-patterned nanoperforated metal oxide thin films. The films were characterized by water contact angle determination, Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Grazing Incidence XRay Diffraction. In this study, well-ordered zinc titanate nanoperforated thin films with different Zn/Ti ratios were produced successfully with zinc precursor content up to 50 mol%, and the dominating phase was Zn2Ti3O8. NP-TiO2 structures were also obtained by a cost-efficient means, namely inkjet printing, at both ambient temperature and 60 °C. To further explore new biosensing applications of nanoperforated oxide thin films, inkjet printing was used for the fabrication of both continuous and patterned polymeric films onto NP-TiO2 and perfluorinated phosphate functionalized NP-TiO2 substrates, respectively. The NP-TiO2 films can be also functionalized with a fluoroalkylsilane, resulting in hydrophobic surfaces on both titania and silica. The surface energy contrast in the nanoperforations can be tuned by irradiating the films with UV light, which provides ideal model systems for wettability studies.

Chapman family home, Fullerton, California, 1908

Chapman family residence, Fullerton, California, ca. 1908. Mounted on heavy weight card stock with small calendar for 1908. "Miss Ethel Chapman" written in ink on top of calendar.

Four days at Niagara Falls, in North America /

Inscription in ink, t.p. verso: James Ainsworth Esq With the respectful com'ts of the author.

Second Welland Canal - Book 1, Survey Map 1 - Entrance, Lock 1 and Port Dalhousie

Survey map of the Second Welland Canal created by the Welland Canal Company showing the areas in and around Port Dalhousie and Grantham Township. Identified structures associated with the Canal include Lock 1, Lighthouse, Lighthouse Keeper's House, East and West Piers, Harbour, Waste Weir, Store House, Collector's Office, Collector Assistant Office, Lock Tender's House and the new towing path. Features of the First Welland Canal are noted in red ink and includes the old Harbour, old Lock 1, old towing path and the original bed of the Twelve Mile Creek. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks and businesses are also identified and include streets and roads (ex. Lock Street and Colonel Clark's Cattle Road), Alex Muir's Dry Dock, RandJ Laurie Flouring Mill, R. Laurie and Company Grist Mill, A. Morrison Saw Mill, Johnson's Tavern, a store and a church. Properties and property owners of note are: Concession 1 Lots 21 and 22, John Christie, John Clark, N. Pawling, William Pawling, W. Carter, G.A. Clark, J. Maven, Mrs. Wood, James Drabble and J. Woodall.

Second Welland Canal - Book 1, Survey Map 2 - Lock 1 and Port Dalhousie

Survey map of the Second Welland Canal created by the Welland Canal Company showing the areas in and around Port Dalhousie and Grantham Township. Identified structures associated with the Canal include Lock 1, East and West Piers, Collector's Office, Lock Tender's House and the new towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Local area landmarks and businesses are also identified and include streets and roads (ex. Road to St. Catharines, Side Line, Old Road to Port Dalhousie, Road to Niagara), the Welland Railway and its structures (ex. freight sheds, wood shed, raised platform, elevator, cranes, water tank, turn table, and passenger station), G. A. Clark's Wood Yard, Clark's Wood Office, Alex Muir's Dry Dock, Donald, Andrews and Ross' Dry Dock, RandJ Laurie Flouring Mill, R. Laurie and Company Grist Mill and A. Morrison Saw Mill. A New Road to St. Catharines is featured in red ink. Properties and property owners of note are: Concession 1 Lots 19, 20 and 21, John Christie, and John Clark.

Second Welland Canal - Book 1, Survey Map 3 - Old Lock 2 in Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township near Port Dalhousie. Identified structures associated with the Canal include the new towing path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old Lock 2, old towing path and the original bed of the Twelve Mile Creek. Local area landmarks are also identified and include streets and roads (ex. Side Line and Old Road), four unnamed bridges, and a tree stump along the old towing path. A New Road to Port Dalhousie is featured in red ink. Properties and property owners of note are: Concession 3 Lots 21, 22 and 23, Concession 4 Lots 21, 22 and 23, Jabez Johnson, Adam Gould, Peter Weaver and Samuel Wood.

Second Welland Canal - Book 1, Survey Map 4 - Through Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township. Identified structures associated with the Canal include the floating tow path and the canal itself. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old towing path. Local area landmarks are also identified and include streets and roads (ex. Line between Wood and Tenbroeck), an unnamed bridge, a poplar tree and walnut tree along the east shore. Properties and property owners of note are: Concession 4 Lot 22, Samuel Wood, and John R. Tenbroeck.

Second Welland Canal - Book 1, Survey Map 5 - Through Grantham Township

Survey map of the Second Welland Canal created by the Welland Canal Company showing a portion of the Grantham Township near Port Dalhousie. Identified structures associated with the Canal include the tow path and floating tow path. The surveyors' measurements and notes can be seen in red and black ink and pencil. Features of the First Welland Canal are noted in red ink and include the old towing path, the Old Canal, two unnamed bridges traversing the Old Canal, and the bed of the Twelve Mile Creek. Local area landmarks are also identified and include streets and roads (ex. Old Road, Side Line, Road to Port Dalhousie), Samuel Wood's house, Peter Weaver's house, J. R. Tenbroeck's house, a poplar and walnut tree along the east shore, an oak and hickory tree along the west shore, and a walnut tree stump along the west shore. Properties and property owners of note are: Concession 3 Lots 21, 22, and 23, Concession 4 Lots 21, 22, and 23, Adam Gould, Samuel Wood, Peter Weaver, and John R. Tenbroeck.