Perlitz, Harald Gottfried. Isikuarhiiv

166 säilikutI Biograafilised materjalid, s.1-7. II Teenistuslikud paberid, s.8-10. III Ettekanded, kõned, artiklid, töömaterjalid. 1. Erialased, s.11-13. 2. Eestimaa ajalugu käsitlevad ja paguluspoliitilised, s.14-23. 3. Tähtpäevalised, s.24-29. IV Kirjavahetus. 1. Perekondlik kirjavahetus, s.30-42. 2. H. Perlitzi kirjad. 2.1. Kirjad asutustele ja organisatsioonidele, s.43-53. 2.2. Kirjad eraisikutele, s.54-108. 3. Kirjad H. Perlitzile. 3.1. Asutuste ja organisatsioonide kirjad, s.109-120. 3.2. Eraisikute kirjad, s.121-157. V Fotod, s.158-159. VI Teiste isikute materjalid, s.160-166http://www.ester.ee/record=b3614278*es

Tartu Ülikool. Nimistu 7: Füüsikaosakond. Arhiivifond

121 säilikutI Füüsikaosakond Keiserlikus Tartu Ülikoolis. 1.Õppetöö. 1.1. Õppeplaanid ja praktikumide kavad, s.1. 1.2. Loengud, s.2. 1.3. Üliõpilastööd, s.3-7. Varia, s.8-10. 2. Varanduslik-majanduslikud dokumendid, s.11-13. 3. Kirjavahetus. 3.1. Kirjad L. F. Kämtzile, s.14-15. 3.2. A. v. Oettingeni kirjavahetus. a) ülikoolisisene, s.16-21, b) teadusasutuste, organisatsioonide, firmadega, s.22-28. c) A. v. Oettingeni kirjad eraisikutele, s.29-37. d) eraisikute kirjad A. v. Oettingenile, s.38-47. 4. Teiste isikute materjalid, s.48. II Füüsikaosakond E. V. Tartu Ülikoolis. 1. Korraldused, juhendid, kodukorrad, aruanded, s.49-52. 2. Õppetöö. 2.1. Õppekavad, õppeplaanid, praktikumide kavad, eksamiprogrammid ja -tähtpäevad, s.58-61. 2.2. Üliõpilastööd, s.62-66. 3. Didaktilis-metoodiline seminar, s.67-68. 4. Teadustöö TÜ füüsikaosakonnas, s.69-73. 4.1. Teadusstipendiaatide materjalid. a) Albrecht Altma, s.74-75. b) Endel Aruja, s.76-79. c) Villem Koern, s.80-90. d) Georg Mets, s. 91-95. 5. Varanduslik-majanduslikud dokumendid, s.96-97. 6. Kirjavahetus. 6.1. TÜ Füüsikainstituudi ning teoreetilise ja tehnilise füüsika laboratooriumi kirjavahetus, s.98-102. 6.2. H. Perlitzi kirjavahetus. a) H. Perlitzi kirjad, s.103-113. b) Kirjad H. Perlitzile, s.114-119. Varia, s.120-121http://www.ester.ee/record=b3574136*es

Test data for the calculation of powder paterns for intermetallic phases

Powder diffraction patterns are often calculated from structural parameters to assist in the identification of materials. To ensure that powder pattern calculations are correct, it is useful to have data to test the computer program doing the calculations. this paper contains test data for each of the crystallographic point groups and 63 of the 230 space groups. An important feature of the data is that many tests involve two high-symmetry structures (sodium and magnesium) that are set in successively lower-symmetry space groups. Thus, the calculated powder intensities for sodium, for example, are identical whatever the setting is. Though the data were chosen to be especially useful for the calculation of the powder patterns of metals and intermetallic compounds, the data have wider utility

Morphology Evolution during Dealloying at High Homologous Temperature

abstract: Dealloying, the selective electrochemical dissolution of an active component from an alloy, often results in nanoscale bi-continuous solid/void morphologies. These structures are attracting attention for a wide range of applications including catalysis, sensing and actuation. The evolution of these nanoporous structures has been widely studied for the case at low homologous temperature, TH, such as in Ag-Au, Cu-Au, Cu-Pt, etc. Since at low TH the solid-state mobility of the components is of order 10-30 cm2s-1 or less, percolation dissolution is the only mechanism available to support dealloying over technologically relevant time scales. Without the necessity of solid-state mass transport, percolation dissolution involves sharp transitions based on two key features, the parting limit and critical potential. Dealloying under conditions of high TH, (or high intrinsic diffusivity of the more electrochemically reactive component) is considerably more complicated than at low TH. Since solid-state mass transport is available to support this process, a rich set of morphologies, including negative or void dendrites, Kirkendall voids and bi-continuous porous structures, can evolve. In order to study dealloying at high TH we have examined the behavior of Li-Sn and Li-Pb alloys. The intrinsic diffusivities of Li were measured in these alloys using electrochemical titration and time of flight measurements. Morphology evolution was studied with varying alloy composition, host dimension and imposed electrochemical conditions. Owing to diffusive transport, there is no parting limit for dealloying, however, there is a compositional threshold (pPD) as well as a critical potential for the operation of percolation dissolution and the formation of bi-continuous structures. Negative or void dendrite morphologies evolve at compositions below pPD and at large values of the applied electrochemical potential when the rate of dealloying is limited by solid-state mass transport. This process is isomorphic to dendrite formation in electrodeposition. Kirkendall voiding morphologies evolve below the critical potential over the entire range of alloy compositions. We summarize our results by introducing dealloying morphology diagrams that we use to graphically illustrate the electrochemical conditions resulting in various morphologies that can form under conditions of low and high TH.Dissertation/ThesisDoctoral Dissertation Materials Science and Engineering 201

Design and development of solid-state functional materials for Na-ion batteries

This Thesis addresses new functional materials for Na-ion battery (NIB) applications. Since the breakthrough of Li-ion battery (LIB), extensive research has been focusing on alternatives to Lithium, based on cheaper and widespread elements for sustainable energy storage solutions. In this context, the effective large-scale deployment of NIB requires great efforts in the development of good Na+ host anodes, high-energy cathodes and safe electrolytes. New components must ensure enhanced efficiency in the NIB operating processes (i.e., Na+ insertion/extraction at the electrode/electrolyte interface and Na+ transport through the electrolyte) for empowering high energy density and long-term cycle stability. Here, we present NIB materials optimization through an innovative approach, based on computational methods that are directly related to experiments. Our aim is to unveil the most important features that can affect the material capabilities towards Na+ uptake, transport and storage. During the research activity at Università di Napoli Federico II, state-of-the-art DFT methods have been employed to investigate the structure-property relationship of solid-state nanoelectrodes. Our studies on TiO2 anatase and MoS2/graphene 2D-heterostructure reveals that sodiation mechanisms are driven by intrinsic structural features. Migration barriers are directly correlated to structure-dependent descriptors, such as the accessible area for the intercalating Na+ at TiO2 surfaces, and the S coordination around the migrating Na+ within MoS2/graphene interface. From these outcomes, we provide new design strategies to improve the electrode efficiency upon sodiation, for example suggesting the preferential growth of TiO2 along the (001) direction or the introduction of S vacancies in MoS2 monolayers. On the cathode side, we unveil the charge compensation mechanism occurring in NaxNi0.25Mn0.68O2 upon desodiation, with a major focus on the O-redox chemistry at very low Na loads. Molecular O2 is predicted to be released from Mn-deficient sites in the bulk cathode via formation of superoxo-species and preferential breaking of labile Ni-O bonds. We prove that increasing M-O covalency via suitable doping would prevent O2 loss and allows to fully recover a reversible process. Research stages at ENS de Lyon and the R&D laboratory of Lithops s.r.l. have been dedicated to the optimization of electrolyte materials. By development and application of polarizable force fields in molecular dynamics simulations, we report reliable predictions of Na+ diffusion and solvation properties into the PyrFSI room-temperature ionic liquid (RT-IL). We combine RT-ILs with cross-linked PEO matrix to obtain highly conductive polymeric membranes. Galvanostatic cycling of Na metal based cells containing these innovative polymer electrolytes and state-of-the-art electrodes shows promising performances and paves the route to further assessment of efficient cells. The foreseen integration of these studies will provide new understanding on the complex charge transfer processes occurring at the electrode/electrolyte interface during battery functioning. The new knowledge on electrochemical behavior of advanced materials will be key for boosting the NIB technology in the near future

The Effect of Impurities on the Processing of Aluminum Alloys

For this Aluminum Industry of the Future (IOF) project, the effect of impurities on the processing of aluminum alloys was systematically investigated. The work was carried out as a collaborative effort between the Pennsylvania State University and Oak Ridge National Laboratory. Industrial support was provided by ALCOA and ThermoCalc, Inc. The achievements described below were made. A method that combines first-principles calculation and calculation of phase diagrams (CALPHAD) was used to develop the multicomponent database Al-Ca-K-Li-Mg-Na. This method was extensively used in this project for the development of a thermodynamic database. The first-principles approach provided some thermodynamic property data that are not available in the open literature. These calculated results were used in the thermodynamic modeling as experimental data. Some of the thermodynamic property data are difficult, if not impossible, to measure. The method developed and used in this project allows the estimation of these data for thermodynamic database development. The multicomponent database Al-Ca-K-Li-Mg-Na was developed. Elements such as Ca, Li, Na, and K are impurities that strongly affect the formability and corrosion behavior of aluminum alloys. However, these impurity elements are not included in the commercial aluminum alloy database. The process of thermodynamic modeling began from Al-Na, Ca-Li, Li-Na, K-Na, and Li-K sub-binary systems. Then ternary and higher systems were extrapolated because of the lack of experimental information. Databases for five binary alloy systems and two ternary systems were developed. Along with other existing binary and ternary databases, the full database of the multicomponent Al-Ca-K-Li-Mg-Na system was completed in this project. The methodology in integrating with commercial or other aluminum alloy databases can be developed. The mechanism of sodium-induced high-temperature embrittlement (HTE) of Al-Mg is now understood. Using the thermodynamic database developed in this project, thermodynamic simulations were carried out to investigate the effect of sodium on the HTE of Al-Mg alloys. The simulation results indicated that the liquid miscibility gap resulting from the dissolved sodium in the molten material plays an important role in HTE. A liquid phase forms from the solid face-centered cubic (fcc) phase (most likely at grain boundaries) during cooling, resulting in the occurrence of HTE. Comparison of the thermodynamic simulation results with experimental measurements on the high-temperature ductility of an Al-5Mg-Na alloy shows that HTE occurs in the temperature range at which the liquid phase exists. Based on this fundamental understanding of the HTE mechanism during processing of aluminum alloy, an HTE sensitive zone and a hot-rolling safe zone of the Al-Mg-Na alloys are defined as functions of processing temperature and alloy composition. The tendency of HTE was evaluated based on thermodynamic simulations of the fraction of the intergranular sodium-rich liquid phase. Methods of avoiding HTE during rolling/extrusion of Al-Mg-based alloys were suggested. Energy and environmental benefits from the results of this project could occur through a number of avenues: (1) energy benefits accruing from reduced rejection rates of the aluminum sheet and bar, (2) reduced dross formation during the remelting of the aluminum rejects, and (3) reduced CO2 emission related to the energy savings. The sheet and extruded bar quantities produced in the United States during 2000 were 10,822 and 4,546 million pounds, respectively. It is assumed that 50% of the sheet and 10% of the bar will be affected by implementing the results of this project. With the current process, the rejection rate of sheet and bar is estimated at 5%. Assuming that at least half of the 5% rejection of sheet and bar will be eliminated by using the results of this project and that 4% of the aluminum will be lost through dross (Al2O3) during remelting of the rejects, the full-scale industrial implementation of the project results would lead to energy savings in excess of 6.2 trillion Btu/year and cost savings of $42.7 million by 2020

Experimental studies of sorption and transport of moisture in cement based materials with supplementary cementitious materials

Most deterioration processes in cement based materials are closely related to moisture sorption and moisture transport properties. Therefore, it is important to study these properties, both theoretically and practically. This work is an experimental investigation in this field. Nowadays, the cement industry produces cements with increasing amounts of supplementary cementitious materials (SCMs) to limit CO2 emissions from concrete production. Knowledge about the moisture properties of concrete made from these blended cements is limited. This project has therefore been an attempt to further develop our understanding of the moisture properties of cement based materials, such as sorption isotherms and sorption transport properties in the presence of SCMs. This has been done by studying sorption isotherms mainly using the sorption balance method, and moisture transport coefficients using both the cup method and a sorption dynamic method. The experimental investigations were made on three types of hydrated cement pastes and mortars (OPC, OPC + 70% slag and OPC + 10% silica fume) with three different w/b –ratios (w/b) for cement paste (0.6, 0.5, 0.4) and two different w/b for cement mortar (0.5, 0.4). Sorption isotherms were determined for cement pastes and mortars in both hygroscopic and the super-hygroscopic relative humidity ranges using the sorption balance method, and the pressure plate method. The conclusion from this part of the study was that the desorption isotherms at low RH (0-30%) for different binders and different w/b-ratios are similar. At higher RHs the samples with silica fume and slag have higher moisture content than OPC samples. This is explained by that they have a higher amount of gel pores and a lower amount of capillary pores than OPC samples. The sorption isotherm at high RHs is difficult to validate experimentally, due to the critical RH of pore solutions. Steady-state and transient measurements of transport coefficients were also made. The dynamic sorption method was used to evaluate the diffusivity in small paste samples. The results show that Fick's law cannot completely describe the transport process in such small samples and sorption behavior is therefore anomalous with two processes with different time scales. One of these is macro-diffusion into the sample, which takes place on a shorter timescale in the small samples used. The second process takes place on longer timescales and it is possibly related to the sorption in nanometer-structure of materials. To better understand the transport properties in sorption cycles, steady-state diffusion coefficients of mortar samples were measured with a newly developed cup method set-up. The measurements were done on both the absorption and desorption limbs of sorption isotherms. For OPC samples the results show a clear difference between the diffusion coefficients in absorption and desorption with vapor content as potential (Dv) and presented as a function of relative humidity (RH). The Dv in desorption is higher than absorption especially at high RHs. For samples with SCMs the dependence of Dv on RH is small. The Dv:s were also recalculated to diffusivity (Dc) using the sorption isotherms to study the effect of different potentials on the effect of hysteresis on transport properties. Key words: Cement, Concrete, Moisture transport, Hysteresis, Supplementary cementitious materials, Water vapor sorption, Sorption isotherms, Anomalous sorptio