Dokumentationen över alla skydden i Borealis AB ligger i ett gammalt EDSA-program och Borealis håller på att ersätta detta program med Vision. Examensarbetet går ut på att, innan Borealis för in uppgifterna om skydden i fabriken till Vision, kontrollera alla lågspänningsskydden för att försäkra sig om att inställningarna är korrekta. I examensarbetet ingår också att göra ström-tid-kurvor för att kontrollera att kortslutningsskyddet klarar uppställda krav och därefter ge förslag till företaget om förbättring. Eftersom många lågspänningsskydd är väldigt gamla, har inventeringen av skydden och skapandet av ström-tid-kurvor varit en stor utmaning. Detta för att manualerna, för de gamla skydden, har otydliga beskrivningar av hur ström-tid-kurvor skapas. Detta har lett till att cirka hälften av alla lågspänningsskydds ström-tid-kurvor inte har dokumenterats. Borealis har tagit fram två förslag till krav på vad ändrade inställningar skall innehålla. Dessa är: ”Lågspänningsskyddet får inte bryta långsammare än 0,2-0,3s vid kortslutningsströmmar” ”Lågspänningsskyddets kortslutningsskydd måste vara inställt lägre än minimal kortslutnings-ström”. Många skydd behöver sänkta inställningar för ström och tid, då de är högre än kravet. Förslag till framtida arbeten är att göra djupare undersökning för alla lågspänningsskydden, speciellt för skydden som är gamla och saknar ström-tid-kurvor. Ett annat förslag är att kontakta leverantören för att skaffa nya manualer till de skydd som har otydliga manualer eller som saknar manualer. I värsta fall kan Borealis behöva köpa nya skydd för att erhålla nya manualer och säkrare skydd. / The documentation of all low-voltage protections at Borealis AB is located in an old EDSA program and Borealis is replacing this program with Vision. The purpose of this diploma work is to check all protections and to ensure that the settings are correct, before Borealis put data on the protections at the factory in Vision. The diploma work also includes making current-time curves to make sure that short-circuit protection meet the necessary requirements and then make suggestions to the company about improvement. Because many low-voltage protections are very old, the inventory of the protections and thecreation of the current-time curves have been a great challenge. The reason is that the manuals for the old protections have unclear description of how the current-time curves are created. This has resulted in that approximately half of all low-voltage current-time curves has no documentations. Borealis has developed two suggested for conditions on what changed settings must include. These are: "Low-voltage protections must not trip slower than 0.2-0.3s at short-circuit currents" "Low-voltage short-circuit protections must be set lower than the minimum shortcircuit current." Many protections needs lower current and time settings, as they are higher than the requirements. A suggestion for future work is to make deeper investigation of all low-voltage protectors, especially for the protectors which are old and lack current-time curves. Another suggestion is to contact the supplier to obtain new manuals which has unclear manuals or lack of manuals. At worst, Borealis has to buy new protection to obtain new manuals and safer protection.

Thèse (Ph.D.)--Université du Québec à Rimouski, 2008. / Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references. Also issued in print.

This thesis documents the academic year progress of researching building in the Arctic circle, household material study in garments, building facade materials, and Arctic experiences with northern lights. This thesis is has many iterations and direction of study from chip board massing models to sewing fabrics to see their integrity. This document shows both design iterations and reflection of each work. The final project of this document is a design proposal for 'The Arctic Experience' - a full service experience for tourists to have a place to visit the arctic circle and view the northern lights. From the provided transportation to their stay in the building, and back they will get to experience the arctic. / Master of Architecture / This document contains thesis iterations and research from the fall and spring academic semesters. The fall semester was research and material study heavy, while the spring semester's project development lead to project design iterations. The fall was spent researching the arctic circle, building construction in that zone, and the aurora Borealis. Then there was a brief shift in ideas - moving toward material study and garment architecture - taking household items and seeing how they can be re-formed. By the end of the thesis, material on building facades was studied and then later a development for the arctic was proposed.

Thesis (Ph. D.)--University of Canterbury, 2001. / Typescript (photocopy). Includes bibliographical references (p. [215]-225). Also available via the World Wide Web.

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No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

R Coronae Borealis (RCB) stars belong to a rare class of variable stars characterized by sudden and unpredictable declines, which are believed to be caused by dust cloud obscuration. In spite of the fact that these stars are so rare (only about 40 are known in our Galaxy), there are many reasons for investigating them. The unusual variability and peculiar chemical composition make them unique among all known types of variable stars. Their evolution and the nature of their unpredictable minima are still not entirely understood. Very few observations of RCB stars during the decline phase exist. Only three RCB stars (R CrB, RY Sgr and V854 Cen) have been studied in detail and only a few declines have been completely covered by observations. This thesis investigates the spectroscopic and photometric characteristics of RCB variables during their decline phases. A programme of photometric and spectroscopic observations of nine RCB and three HdC stars has been undertaken at Mt John University Observatory (MJUO) over a period of two and a half years. The programme includes some typical examples of RCB stars (Teff ~ 7000 K), as well as some cool ones (Teff ~ 5000 K). One of the most unusual of all RCB stars, V854 Cen, is also included. The photometric observations, as part of the long-term monitoring of RCB stars at MJUO, have provided the UBVRIphotometry and have served as a decline indicator. Complex colour changes during the declines were monitored and compared with the spectroscopy. The photometry during the recovery phases of the nine RCB stars in the last 12 years was used for studying the extinction properties of the gas obscuring the photosphere. An analysis of 26 different declines shows that the material causing the declines has extinction properties similar to those of the interstellar medium. The medium and high-resolution spectroscopy has been obtained for six declines of different programme stars using the 1-m telescope at MJUO. Although the duration and depth of the declines are very different, they all show similar photometric and spectroscopic characteristics. The results have been compared with other observations and used to examine a simple line-region model (E1/E2/BL), which attempts to describe the evolution and origin of emission lines during a decline. In general, the evolution of various emission lines observed in this work is consistent with their classification into these three groups. However, some characteristics of the emission lines indicate a different origin from that suggested by the model. A very rich emission line spectrum was monitored during the 1998 decline of V854 Cen, while only the most prominent lines were observed in the other stars. Short-lived high-excitation lines from the initial decline phase, such as CI and 01, were classified as Ei. They show a characteristic, shock-induced red shift indicating the photospheric origin. Lines classified as E2 are mainly from the low-excitation ions and neutral atoms. All lines from this group appear at the very beginning of the decline and are visible through to the late recovery phase, slightly blue-shifted relative to the stellar velocity. The lines of the low-excitation ions exhibit a complex structure with a strong central and two weaker components, one on each side. Their absolute flux evolution has been compared with the changes in the stellar continuum flux. The behaviour of these lines indicates that they are not affected by the dust cloud in the same way as the photospheric continuum. Assuming that the dust cloud is formed at about 2R* and taking into account the acceleration obtained from the analysis of the high-velocity Nal D absorption lines, the position of the E2 line emitting region was estimated to be about 3R* - 5R*. The third group (BL) consists of broad emission lines, which are a typical feature of all observed declines. The most prominent broad lines present in all RCB stars belong to the Nal D doublet. The observations demonstrate that these lines are the strongest in V854 Cen, due to the significant amount of material produced by its frequent declines. In contrast to the E2 lines, whose fluxes have been found to decrease during the decline, the absolute flux of the broad lines stays constant throughout the whole decline phase. This is consistent with the idea that the broad emission is a permanent feature, whose visibility depends only on the photospheric brightness. Various Nal D components (sharp and broad emission and high-velocity absorption) have been analysed in a number of RCB declines and presented in this thesis. The high-velocity blue-shifted Nal D absorption demonstrates similar velocities (between -230 kms-1 and -400 kms-1), structure and behaviour in the different declines. The observations from the 1998 decline of V854 Cen clearly show that the high-velocity absorption lines can also appear during the initial decline phase. This suggests that they can be associated with the clouds formed in some previous declines, as well as with the current one. The spectroscopic observations of the 1998 decline of V854 Cen obtained in this thesis represent the first almost complete coverage of a decline of this star.

Photoelectric photometry of a large sample of R CrB and hydrogen-deficient carbon stars was obtained over a period of five months in order to search for variability and determine the period if variable. All the stars in the sample were found to be variable. Only for the stars S Aps, U Aqr and V CrA were sufficient observations obtained to enable periods to be identified. The determined periods were 39.7, 41.8 and 69.0 days respectively. These periods are in agreement with the theoretical period-temperature relationship. Photoelectric photometry of the hot hydrogen-deficient star DY Cen was obtained over a period of four weeks. DY Cen was confirmed to be variable and the dominate period of 3.8 days determined. This period was consistent with the period-temperature relationship. Model atmospheres were calculated for hydrogen-deficient compositions with temperatures between 5000-8000K and surface gravities between 0.0 and 4.4. The models included the effects of molecular formation, convection and line-blanketing. It was shown that the temperature structure was strongly dependent on the composition, in particular the ratios of C/He and H/He. R CrB was re-analysed using these new models. The derived atmospheric parameters were T[subscript(eff)] = 7400 ± 500K, log g = 0.55 ± 0.25, ξ[subscript(t)] = 8 ± 2kms⁻¹ and C/He=0.005. High resolution spectra were obtained of RY Sgr in order to do a similar analysis. The derived parameters were T[subscript(eff)] = 7000 ± 500K, log g = 0.65 ± 0.25, ξ[subscript(t)] = 10 ± 2kms⁻¹ and C/He=0.005. Both stars were found to have solar metallicities with no over-abundances of s-process elements. The abundances of C, N and O were all enhanced relative to the solar values. Medium resolution spectra were obtained at the Isaac Newton telescope of suspected R CrB stars in order to correctly classify them. The stars were classified on the basis of the strength of the hydrogen lines and the G band. BG Cep, LO Cep, CC Cep, DZ And, RZ Vul, VZ Vul, V638 Her and V1405 Cyg were all classified as not being R CrB stars. UV Cas, SU Tau and SV Sge were classified as R CrB stars.

R Coronae Borealis (RCB) stars belong to a rare class of variable stars characterized by sudden and unpredictable declines, which are believed to be caused by dust cloud obscuration. In spite of the fact that these stars are so rare (only about 40 are known in our Galaxy), there are many reasons for investigating them. The unusual variability and peculiar chemical composition make them unique among all known types of variable stars. Their evolution and the nature of their unpredictable minima are still not entirely understood. Very few observations of RCB stars during the decline phase exist. Only three RCB stars (R CrB, RY Sgr and V854 Cen) have been studied in detail and only a few declines have been completely covered by observations. This thesis investigates the spectroscopic and photometric characteristics of RCB variables during their decline phases. A programme of photometric and spectroscopic observations of nine RCB and three HdC stars has been undertaken at Mt John University Observatory (MJUO) over a period of two and a half years. The programme includes some typical examples of RCB stars (Teff ~ 7000 K), as well as some cool ones (Teff ~ 5000 K). One of the most unusual of all RCB stars, V854 Cen, is also included. The photometric observations, as part of the long-term monitoring of RCB stars at MJUO, have provided the UBVRIphotometry and have served as a decline indicator. Complex colour changes during the declines were monitored and compared with the spectroscopy. The photometry during the recovery phases of the nine RCB stars in the last 12 years was used for studying the extinction properties of the gas obscuring the photosphere. An analysis of 26 different declines shows that the material causing the declines has extinction properties similar to those of the interstellar medium. The medium and high-resolution spectroscopy has been obtained for six declines of different programme stars using the 1-m telescope at MJUO. Although the duration and depth of the declines are very different, they all show similar photometric and spectroscopic characteristics. The results have been compared with other observations and used to examine a simple line-region model (E1/E2/BL), which attempts to describe the evolution and origin of emission lines during a decline. In general, the evolution of various emission lines observed in this work is consistent with their classification into these three groups. However, some characteristics of the emission lines indicate a different origin from that suggested by the model. A very rich emission line spectrum was monitored during the 1998 decline of V854 Cen, while only the most prominent lines were observed in the other stars. Short-lived high-excitation lines from the initial decline phase, such as CI and 01, were classified as Ei. They show a characteristic, shock-induced red shift indicating the photospheric origin. Lines classified as E2 are mainly from the low-excitation ions and neutral atoms. All lines from this group appear at the very beginning of the decline and are visible through to the late recovery phase, slightly blue-shifted relative to the stellar velocity. The lines of the low-excitation ions exhibit a complex structure with a strong central and two weaker components, one on each side. Their absolute flux evolution has been compared with the changes in the stellar continuum flux. The behaviour of these lines indicates that they are not affected by the dust cloud in the same way as the photospheric continuum. Assuming that the dust cloud is formed at about 2R* and taking into account the acceleration obtained from the analysis of the high-velocity Nal D absorption lines, the position of the E2 line emitting region was estimated to be about 3R* - 5R*. The third group (BL) consists of broad emission lines, which are a typical feature of all observed declines. The most prominent broad lines present in all RCB stars belong to the Nal D doublet. The observations demonstrate that these lines are the strongest in V854 Cen, due to the significant amount of material produced by its frequent declines. In contrast to the E2 lines, whose fluxes have been found to decrease during the decline, the absolute flux of the broad lines stays constant throughout the whole decline phase. This is consistent with the idea that the broad emission is a permanent feature, whose visibility depends only on the photospheric brightness. Various Nal D components (sharp and broad emission and high-velocity absorption) have been analysed in a number of RCB declines and presented in this thesis. The high-velocity blue-shifted Nal D absorption demonstrates similar velocities (between -230 kms-1 and -400 kms-1), structure and behaviour in the different declines. The observations from the 1998 decline of V854 Cen clearly show that the high-velocity absorption lines can also appear during the initial decline phase. This suggests that they can be associated with the clouds formed in some previous declines, as well as with the current one. The spectroscopic observations of the 1998 decline of V854 Cen obtained in this thesis represent the first almost complete coverage of a decline of this star.