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2462. Crack initiation criteria for singular stress concentrations. Part III. An application to a crack touching a bimaterial interface
- Creator:
- Náhlík, Luboš, Knésl, Zdeněk, and Klusák, Jan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- bimaterial interface, stability criteria, crack propagation, critical stress, and threshold stress
- Language:
- English
- Description:
- The paper deals with crack propagation through an interface between two elastic materials. The basic idea of developing stability criteria of general singular stress concentrators introduced in the first part is applied to the case of a crack with its tip at the interface between two different materials. Three different stability criteria based on different physical principles are presented and a numerical example with their mutual comparison is carried out. A procedure based on a generalized strain energy density factor is shown which makes it possible to estimate the further direction of crack propagation after the crack has passed the interface. The procedure presented is applied in the numerical examples. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2463. Crack initiation criteria for singular stress concentrations. Part IV. Applications to fracture of coated structures
- Creator:
- Knésl, Zdeněk, Náhlík, Luboš, and Bareš, Pavel
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fracture mechanics, bi-material body, thin layers, and fracture of coated structures
- Language:
- English
- Description:
- The influence of through crack in the protective surface layer on damage of coated structure is investigated. The coated structure is modeled as a particular case of a bi-material body consisting of thin surface layer on the substrate. The problem is studied under the assumptions corresponding to small scale yielding conditions and calculations are performed by the finite element method. Specific attention is devoted to the case of a through coating crack with its tip at the interface between coating and the substrate. To estimate how the coating crack with its tip at the interface influences the substrate failure the general approach described in [1, 2, 3] (Part I, II, III of this contribution) is applied. An aproximate approach based on calculations of crack mouth opening displacement for thin protective layers is suggested and developed. It is concluded that in the case of a stiffer coating on a more compliant substrate, the through coating cracks represent dangerous stress concentrators and as a consequence of elastic mismatch of both materials, the critical applied stress for substrate failure decreases. Traditional approaches may have underestimated this effect and estimations of the service life of coated structures neglecting this phenomenon could lead to non-conservative values, with unexpected failures. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2464. Crassulacean Acid Metabolism 1975-2000, a check list
- Creator:
- Sayed, O. H.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- angiosperms, CAM inducers, CAM modifications, CAM types, carbon discrimination, ferns, gymnosperms, habitat, and phosphoenolpyruvate carboxylase
- Language:
- Multiple languages
- Description:
- A list of plant species documented over the past 25 years to exhibit Crassulacean Acid Metabolism (CAM) is presented. The list compiles all available information on these species including their growth habits, succulent parts, carbon isotope discrimination values, CAM types, CAM inducers, and CAM modifications.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2465. Crassulacean acid metabolism and survival of asexual propagules of Sedum wrightii
- Creator:
- Gravatt, D. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- asexual reproduction, dry mass, malic acid, plantlet, stonecrop, and water content
- Language:
- Multiple languages
- Description:
- In Sedum wrightii grown in a growth chamber, detached leaves could survive for at least 120 d with a high rate of success for propagule formation. The pattern of gas exchange, associated with CAM, may be important in extending the period during which the detached leaf remains physiologically active. The added benefit for the developing propagule, still attached to the "parent" leaf, is an additional source of water and saccharide reserves over an extended period necessary for rooting. Drought survival of propagules may be determined by the amount of water-storing tissue in the detached leaf.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2466. Crassulacean acid metabolism in the epiphytic fern Patycerium bifurcatum
- Creator:
- Rut, G., Krupa, J., Miszalski, Z., Rzepka, A., and Ślesak, I.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- abscisic acid, chlorophyll fluorescence, drought stress, malate, net photosynthetic rate, photosystem 2, and stomatal conductance
- Language:
- Multiple languages
- Description:
- The epiphytic fern Platycerium bifurcatum grows in different habitats characterized by drought and high irradiance stress. The plant shows diurnal malate oscillations, indicative for CAM expression only in cover leaves, but not in sporotrophophyll. In P. bifurcatum cover leaves exposed to high irradiance and desiccation, the decrease in both CO2 assimilation (PN) and stomatal conductance (gs) was accompanied with occurrence of diurnal malate oscillations. Exogenously applied abscisic acid (ABA) induced the decrease in PN and gs, but no clear change in malate oscillations. The measurements of the maximum quantum efficiency of photosystem 2 (Fv/Fm) under high irradiance showed distinct photoinhibition, but no clear changes in Fv/Fm due to desiccation and ABA-treatment were found. and G. Rut ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2467. Creatine kinase reaction in skinned rat psoas muscle fibers and their myofibrils
- Creator:
- Gregor, M., Jiří Mejsnar, Alena Janovská, Jitka Žurmanová, Oldřich Benada, and Blanka Mejsnarová
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, svaly, muscles, skinned fibers, myofibrils, creatine kinase, substrate channeling, 14, and 612
- Language:
- English
- Description:
- The aim of this study was to evaluate myofibrillar creatine kinase (EC 2.7.3.2) activity on the background of the effect of substrate channeling by myosin ATPase and to compare it with creatine kinase (CK) activity of whole skinned fibers. In order to assess CK activity, skinned fibers were prepared from the rat psoas major muscles defined by light microscopy. The activity in permeabilized fibers after treatment with saponin, Triton X-100 and Ca2+-free medium reached 2.80, 6.97 and 3.32 m mol ATP min-1 mg-1 protein, respectively, when a coupled enzyme assay system with external hexokinase and glucose-6-phosphate dehydrogenase was used. Transmission electron microscopy (TEM) revealed a possible interference among activities of sarcolemmal, sarcoplasmic, myofibrillar and mitochondrial CK from persisting structures. For evaluation of the myofibrillar CK itself, a pure myofibrillar fraction was prepared. Fraction purity was confirmed by TEM and by enzymatic assays for marker enzymes. Two procedures, i.e. the coupled enzyme assay and the evaluation of phosphocreatine (Pcr) concentration before and after the CK reaction, were used for measurement of CK activity in this fraction. The procedures resulted in 3.2 nmol ATP min-1 mg-1 protein and 7.6 nmol PCr min-1 mg-1 protein, respectively. These alternative approaches revealed a discrepancy between the reacting portions of Pcr by more than 50 % , which provides information about the size of the effect, generally described as substrate channeling., M. Gregor, J. Mejsnar, A. Janovská, J. Žurmanová, O. Benada, B. Mejsnarová., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2468. Creating a winner's curse via jump bids
- Creator:
- Ettinger, David and Michelucci, Fabio
- Publisher:
- CERGE-EI
- Format:
- electronic, svazek, and 22 stran
- Type:
- model:monograph and TEXT
- Subject:
- Ekonomie, aukce, modelování a simulace, auctions, modeling and simulation, 339.375, 519.86/.87, (048.8), 4, and 33
- Language:
- English and Czech
- Description:
- David Ettinger, Fabio Michelucci., Obsahuje bibliografii a bibliografické odkazy, and Český a anglický abstrakt
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2469. Creative nonfiction in social science: towards more engaging and engaged research
- Creator:
- Kotišová, Johana
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- creative nonfi ction, ethics, writing, social sciences, kreativní nonfikce, etika, psaní, sociální vědy, and afordance
- Language:
- Czech
- Description:
- Th e paper aims at identifying, explaining and illustrating the aff ordances of “creative nonfi ction” as a style of writing social science. Th e fi rst part introduces creative nonfi ction as a method of writing which brings together empirical material and fi ction. In the second part, based on illustrations from my ethnographic research of European “crisis reporters,” written in the form of a novel about a fi ctional journalist, but also based on a review of existing social science research that employs a creative method of writing, I identify several main aff ordances of creative nonfi ction in socialscientifi c research. In particular, I argue that creative nonfi ction allows scientists to illustrate their fi ndings, to express them in an allegorical way, to organize data into a narrative, to let their pieces of research act in the social world, and to permeate research accounts with self-refl exive moments. I also discuss some apparent negative aff ordances: challenges that creative nonfi ction poses to readers and to the institutionalized academic discourse. Finally, I suggest that writing about sociological problems in the style of creative nonfi ction can help to produce more engaging and engaged texts, and I discuss the ethical implications of the approach. and Článek identifi kuje, vysvětluje a ilustruje afordance „kreativní nonfi kce“ jako stylu psaní o sociální vědě. V první části představuji kreativní nonfi kci jako metodu psaní, která kombinuje empirický materiál a imaginaci. Ve druhé části na základě ukázek z vlastního etnografi ckého výzkumu evropských “krizových reportérů”, psaného formou románu o fi ktivním novináři, a také na základě jiných sociálněvědných výzkumů, které používají kreativní metody psaní, identifi kuji několik hlavních afordancí kreativní nonfi kce v sociálněvědním výzkumu. Kreativní nonfi kce zejména umožňuje vědkyním a vědcům jinak a někdy lépe ilustrovat jejich zjištění, vyjádřit tato zjištění alegoricky, organizovat data a vytvářet narativ, podpořit efektivitu výzkumů v sociálním světě nebo také proložit výzkumný narativ seberefl exivními prvky. Text ale diskutuje i zjevné negativní afordance, tedy výzvy, které potenciálně plynou ze setkání kreativní nonfi kce se čtenářstvem a s institucionalizovaným akademickým diskurzem. Nakonec diskutuji některé etické implikace představeného přístupu a tvrdím, že psát o sociologických problémech ve stylu kreativní nonfi kce může pomoct vytvářet texty, které budou angažované i poutavé.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2470. Credit ratings and their information value: evidence from the recent financial crisis
- Creator:
- Kuvíková, Gabriela
- Publisher:
- CERGE-EI
- Format:
- electronic, svazek, and 60 stran : tabulky.
- Type:
- model:monograph and TEXT
- Subject:
- Finance, Financial Information Services, Standard and Poor's Corporation, rating, finanční rizika, ekonomické informace, credit rating, financial risks, business information services, 659.233, 336.7:330.131.7, 659.23, (048.8), 4, and 336.7
- Language:
- English and Czech
- Description:
- Gabriela Kuvíková., Obsahuje bibliografii a bibliografické odkazy, and Český a anglický abstrakt
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public