Regulators and cycle maps in higher-dimensional differential algebraic K-theory

We develop differential algebraic K-theory of regular arithmetic schemes. Our approach is based on a new construction of a functorial, spectrum level Beilinson regulator using differential forms. We construct a cycle map which represents differential algebraic K-theory classes by geometric vector bundles. As an application we derive Lott's relation between short exact sequences of geometric bundles with a higher analytic torsion form.Comment: 106 pages (corrects a mistake in the sheaf condition), published versio

Novel Wood Resistance Measurement Method Reducing the Initial Transient Instabilities Arising in DC Methods Due to Polarization Effects

A novel method for measuring the electrical resistance in wood is presented. It is based on applying an Alternating Current (AC) to two electrodes rammed into the wood. The method reduces the transient time for value stabilization. In case of Direct Current (DC) resistance measurement methods, typically used in wood measurement, an initial transient exists, invalidating the measured value during an initial transient period. This measurement method uses an electronic circuit based on a relaxation oscillator where the wood automatically sets the oscillation frequency depending on its electrical resistance. Compared to other AC methods, this circuit greatly simplifies the measurement process, not requiring any previous analysis for wood AC frequency estimation. Experimental results for four different wood species showed that, in all cases, the transient response of the measured wood resistance is improved when compared to the DC resistance method, reducing the stabilization time from 10-12 min in DC measurements to almost zero for the novel measurement method. The deviation between the initial wood resistance measurement and the stable value resulted in a range between 0.2% and 5% with the proposed method, while a range between 6% and 10% was obtained when using the DC method. Moreover, the proposed circuit is able to detect changes in wood resistance produced by small variations in temperature and environmental relative humidity during continuous long term measurements. For repeatability analysis, it was verified that similar ambient conditions of temperature and relative humidity (variations lower than 1 °C and 1%, respectively) in different moments provided variations lower than 1.5%. The method can also be applied to other fiber materials affectd by polarization effects when an electrical current is applied into them

Development of media for dynamic latent heat storage for the low-temperature range. Part 1: Thermal analyses of selected salt hydrate systems

Phase change temperatures and phase change enthalpies of seventeen salt hydrates, three double salts, and four eutectics were measured thermodynamically and the results reported herein. Good results were obtained, especially for congruently melting salt hydrates. Incongruently melting salt hydrates appear less suitable for heat storage applications. The influence of the second phase - water, acid and hydroxide - to the latent heat is described. From these results, basic values of the working temperatures and storage capabilities of various storage media compositions may be derived

Protsessi juhtimise tarkvaraline raamistik puidu konvektiivkuivatuse ja spektroelektrokeemia näidetel

http://tartu.ester.ee/record=b2655206~S1*es

Keskkonna heterogeensuse ja taimede mitmekesisuse seos väikesel ruumiskaalal

Väitekirja elektrooniline versioon ei sisalda publikatsioone.Küllap olete märganud, et mida mitmekesisem on ümbritsev keskkond, seda rohkem leidub seal ka erinevaid elusorganisme. Näiteks alal, kus on lähestikku kuiv niit, niiske rohumaa ja tiik, elutseb rohkem liike, kui niidul üksi. Positiivne seos keskkonna heterogeensuse ja liigilise mitmekesisuse vahel on üldlevinud arusaam ökoloogias ning aluseks mitmetele ökoloogilistele teooriatele ja otsustele looduskaitses. Milline on aga olukord, kui näiteks niidul on erinevad keskkonnatingimused omakorda laiguliselt paigutunud? Kas selline väikeseskaalaline keskkonna heterogeensus lubab samuti rohkematel liikidel koos elada? Mitmed varasemad uurimistööd taimekooslustes on näidanud, et keskkonnatingimuste väikeseskaalaline laigulisus võib taimede mitmekesisusele hoopis negatiivset mõju avaldada. Selle töö eesmärgiks oli välja selgitada, miks ja kuidas keskkonna heterogeensus väikesel ruumiskaalal taimede mitmekesisust vähendab. Kasutades andmeid varasematest töödest, mudelsimulatsioonist ja kasvuhoonekatsest, leidsime, et väikesel ruumiskaalal on heterogeensuse-mitmekesisuse seos enamasti negatiivne ning seda kahel põhjusel. Esiteks, kui keskkonnalaigud on suuremad kui taimeisendid, võib heterogeensus takistada levimist ning seeläbi vähendada taimepopulatsioonide elujõulisust ja koosluse liigirikkust. Mida heterogeensem on keskkond, seda suurem on tõenäosus, et ümbritsevad keskkonnatingimused ei ole järglastele sobivad ning levida tuleb kaugemale. Teiseks, kui keskkonnalaigud on taimeisendist väiksemad, on edukamad sellised liigid, mis suudavad kiiresti paigutada oma juured või maapealsed võsundid sobivasse keskkonnalaiku. Need liigid saavad kasvada suuremaks ning seeläbi tõrjuda kooslusest välja väiksemad või aeglase kasvuga liigid, mis sobivate tingimusteni ei jõuagi. Keskkonna väikeseskaalaline heterogeensus on looduses tavaline nähtus ning selle negatiivset mõju taimekooslustele peaks arvesse võtma ka järgnevates uurimistöödes ja looduskaitses.Have you noticed that environments that exhibit various conditions support higher species diversity? For example, one can probably find more species in an area that has patches of dry grasslands, wet meadows and ponds than in a uniform grassland area. This positive relationship between environmental heterogeneity and species diversity is a common knowledge in ecology, and forms a basis for several ecological theories and nature conservation decisions. But what if environmental conditions are heterogeneously distributed also within a community; for example, some patches are more fertile than others? Does this small-scale environmental heterogeneity also support more species? Several studies in plant communities have shown that environmental heterogeneity occurring at small spatial scales has a negative effect on plant co-existence. In this thesis, I shed further light on the negative heterogeneity-diversity relationship and describe mechanisms behind this pattern. We used data from previous studies, a computer simulation and a greenhouse experiment and found that small-scale heterogeneity can negatively impact on species diversity in two ways, depending on the relative sizes of plant individuals and habitat patches. If the patches are larger than individuals, heterogeneity can restrict dispersal between suitable patches that become more isolated. This decreases population sizes and lowers species diversity. If the patches are smaller than plant individuals, large and fast-growing species can quickly forage through different quality patches and take advantage of heterogeneous conditions, outcompeting small and slow-growing species. Small-scale heterogeneity is common in nature and can have significant impacts on community structure. Understanding the mechanisms behind a negative heterogeneity-diversity relationship can help to predict future changes in plant communities and aid conservation decisions

Puidu kuivatuse kontrolli ja optimeerimise meetodite arendamine

A Thesis for applying for the degree of Doctor of Philosophy in Forestry.Väitekiri filosoofiadoktori kraadi taotlemiseks metsanduse erialal.The purpose of wood drying is to obtain material with the desired final moisture content. During the process, it is necessary to find a balance between the quality of the wood and the energy and time spent. In order to find an optimal solution, it is important to know the condition of the material to be dried at a specific time. Often, the standard equipment of an industrial kiln is not enough when implementing a new drying schedule. In addition, there is a need for software that simulates wood drying, providing the initial drying regime, which can then be further optimized using the methodologies and sensors presented in this study. This work checks the occurrence of theoretically simulated moistening impulse response in experiments based on synchronous surface displacement, temperature and surface moisture sensors. For this purpose, it was necessary to develop specific sensors used for wood monitoring in the wood dryer climate. A physically justified measurement result is guaranteed when using sensors based on different working principles. When investigating the reliability of the sensors, typical issues and practically usable measurement ranges below and above the saturation point of the wood fiber were identified. The transition of the surface layer of wood from the first phase of drying to the second phase of drying was investigated. It was found that the transition of the surface layer to the second drying phase slows down the diffusion rate in the inner layers of the wood, which otherwise could still be in the first phase of drying due to their moisture content. In order to characterize the influence of the diffusion constant of the surface layer on the inner layers, the concept of critical diffusion constant was defined. In the process of wood drying, individually calibrated carbon fiber needle-electrodes were used to record the moisture content of wood at different depths from the surface of the board being dried. When creating an optimized drying plan taking into account the critical diffusion constant, it was possible to significantly shorten the drying time of a typical industrial drying plan at the same final moisture content. The optimized drying schedule was characterized by a higher drying strain, which can level down by a timed moistening pulse. In this thesis, the relative humidity value of the critical drying air corresponding to the critical diffusion constant for pine wood was found. It is easy for a timber company to use this information to modify its drying schedules on site. An electrical indicator of maximum wood drying stresses was also developed. Since the electrical resistance method is mostly used for wood drying monitoring in practice, the hardware and software of the patented polarization-type moisture meter prototype were improved. Galvanostatic charging mode and depolarization voltage monitoring capability was added.Puidu kuivatamise eesmärgik on saada soovitud lõppniiskusega materjali. Protsessi käigus on vaja leida tasakaal puidu kvaliteedi, kulutatud energia ning aja vahel. Optimaalse lahenduse leidmiseks on oluline teada millises seisus on konkreetsel ajahetkel kuivatatav materjal. Sageli ei piisa tööstusliku puidukuivati standardvarustusest uue kuivatusplaani juurutamisel. Lisaks on vaja puidu kuivatamist simuleerivat tarkvara, mis annab esialgse kuivatusrežiimi, mida saab edasi optimeerida, kasutades käesolevas töös toodud metoodikaid ja andureid. Käesolevas töös on kontrollitud kas teoreetiliselt simuleeritud niisutusimpulsi reaktsioon ilmneb ka katses, tuginedes sünkroonselt pinna nihke-, temperatuuri-, ja pinnaniiskuse andurile. Selleks oli tarvis välja töötatada spetsiifilised puidukuivati kliimas puidu monitooringuks kasutatavad andureid. Erinevatel tööprintsiipidel põhinevate andurite kasutamisel on tagatud füüsikaliselt põhjendatav mõõtetulemus. Andurite töökindluse uurimisel selgitati välja tüüpilised probleemid ja praktikas kasutatav mõõtepiirkond alla ning üle puidu kiu küllastuspunkti. Uuriti puidu pinnakihi üleminekut kuivatuse esimesest faasist teise kuivatuse faasi. Leiti, et pinnakihi üleminek teise kuivatuse faasi aeglustab difusiooni kiirust ka puidu sisekihtides, mis muidu oma niiskusesisalduse poolest võiksid veel olla kuivatuse esimeses faasis. Pinnakihi difusiooni konstandi mõju iseloomustamiseks sisekihtidele defineeriti kriitilise difusiooni konstandi mõiste. Puidukuivatuse protsessis puidu niiskusesisalduse registreerimiseks kuivatatava laua pinnast erinevatel sügavustel kasutati individuaalselt kalibreeritud süsinikkiud nõel–elektroode. Kriitilise difusioonikonstandi arvesse võtmisega optimeeritud kuivatusplaani koostamisel õnnestus tüüpilise tööstusliku kuivatamise plaani kuivatuse aega oluliselt lühendada sama lõppniiskuse juures. Optimeeritud režiimi iseloomustasid mõnevõrra suuremad suhtelised pinged mis on tasandatavad ajastatud niisutusimpulsiga. Käesolevas väitekirjas leiti männipuidu jaoks kriitilisele difusiooni konstandile vastav kriitilise kuivatusõhu suhtelise niiskuse väärtus. Seda infot on puiduettevõtetel lihtne kuivatusplaanide modifitseerimiseks kasutada. Samuti töötati välja puidukuivatuse pingete maksimumi elektriline indikaator. Kuna puidukuivatuse monitooringuks kasutatakse praktikas valdavalt elektrilist takistusmeetodit siis täiustati patendeeritud polarisatsioon-tüüpi niiskusmõõturi prototüübi riistvara ja tarkvara

The Relative Chern Character and Regulators

In this thesis we construct a modified version of Karoubi's relative Chern character for smooth varieties over the complex numbers or the ring of integers in a p-adic number field. Comparison results with the Deligne-Beilinson Chern character and the p-adic Borel regulator constructed by Huber and Kings are proven. As a corollary we obtain a new proof of Burgos' theorem that Borel's regulator is twice Beilinson's regulator.Comment: doctoral thesis, University of Regensburg, 144 page

A Multiple Case Exploration Of Designers And Reflection In The Design Space

For decades, scholars have searched for ways to more effectively teach and practice instructional design. A variety of strategies have been employed to address the ambiguity in and challenges of the field. Much of the focus in the education of instructional designers has been on teaching students how best to use the many models developed for the field (Rowling, 1992). These efforts, while meant to help the new instructional designer succeed, have often been stifled by the ever-changing landscape of what instructional designers are asked to do in their roles after graduation (Kenny, Zhang, Schwier, & Campbell, 2005). Other research centers around the ways students can fuse their new instructional design knowledge with practical activities. While many scholars have begun to focus on alternative methods for preparing instructional designers and improving instructional design processes, instructional designers themselves have been neglected. We teach instructional designers about the profession before we have truly understood the professional. From a teaching standpoint, this approach contradicts the very foundation of instructional design education: that of recognizing that the learners/users are at the center of instructional design (Cennamo & Kalk, 2004). The purpose of this qualitative study was to examine instructional designers during design by engaging them in structured reflection as (a.) a way to better understand instructional designers in the design space and (b.) a technique for instructional designers to improve their design. Seven designers were asked to explore their thoughts, feelings, and experiences over six weeks while engaged in a design project. This study used various data collection methods including reflection journals, interviews, and surveys. The Self-Reflection Insight Scale (SRIS) and REFLECT rubric were utilized to measure reflection abilities, and grounded theory was employed to conceptualize the data (Strauss & Corbin, 1990), while concentrating on discovery and the development of theory (Charmaz, 1983). Results showed that each designer is unique; designers rely on distinctive designer precedents; designers perceive reflection to positively impact their design products; designers\u27 depth of reflection waxes and wanes; and designers reflect more deeply when provided with feedback

Piecewise polynomial collocation for linear boundary value problems of fractional differential equations

AbstractWe consider a class of boundary value problems for linear multi-term fractional differential equations which involve Caputo-type fractional derivatives. Using an integral equation reformulation of the boundary value problem, some regularity properties of the exact solution are derived. Based on these properties, the numerical solution of boundary value problems by piecewise polynomial collocation methods is discussed. In particular, we study the attainable order of convergence of proposed algorithms and show how the convergence rate depends on the choice of the grid and collocation points. Theoretical results are verified by two numerical examples