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5632. Critical buckling stress of patch loading
- Creator:
- Baláž, Ivan and Koleková, Yvona
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- patch loading, elastic critical stress, buckling coefficient, and parametrical study
- Language:
- English
- Description:
- Elastic critical buckling stress of the plate girder subjected to transverse force is calculated. The load is applied through the flange and resisted by shear forces in the web. Comparisons of values of buckling coefficient kσ,b = f (α, β) (Tab.2) obtained by 5 various authors: Petersen, von Berg, Ravinger, Kutzelnigg, Protte (Tab. 1) and calculated by computer program PLII (Tab. 2). Simply supported rectangular plate (a - length, b - width, t - thickness) without flanges and stiffeners is investigated for different aspect ratios α = a/b = 1; 2; 3; 4; 5; 8; 10; 20; 30; 40 when subjected to transverse uniformly distributed partial load having relative load lengths β = c/a = 0.005 (single concentrated force); 0.2; 0.4; 0.6; 0.7; 0.8; 1 (uniformly distributed load along a). The values of buckling coeffficient kσ,b = f (α, β, δ) calculated by program PLII (Tab. 3). Parametrical study of simply suppported rectangular plate without stiffeners with α = a/b = 4; 5; 8; 10; 20; 30; 40, β = c/a = 0.005 (single concentrated force); 0.01; 0.05; 0.1; 0.2; 0.3; 0.4 and different relative normal flange rigidity δ = Af / (b t) = 0 (without flange); 0.3; 0.5; 1; 1.5; 2; 3. Torsional rigidity of the flanges is not taken into account. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5633. Critical case of nonlinear Schrödinger equations with inverse-square potentials on bounded domains
- Creator:
- Suzuki, Toshiyuki
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- energy method, nonlinear Schrödinger equation, inverse-square potential, and Hardy-Poincaré inequality
- Language:
- English
- Description:
- Nonlinear Schrödinger equations (NLS)a with strongly singular potential a|x| −2 on a bounded domain Ω are considered. If Ω = R N and a > −(N − 2)2 /4, then the global existence of weak solutions is confirmed by applying the energy methods established by N. Okazawa, T. Suzuki, T. Yokota (2012). Here a = −(N − 2)2 /4 is excluded because D(P 1/2 a(N) ) is not equal to H 1 (R N ), where Pa(N) := −∆ − (N − 2)2 /(4|x| 2 ) is nonnegative and selfadjoint in L 2 (R N ). On the other hand, if Ω is a smooth and bounded domain with 0 ∈ Ω, the Hardy-Poincaré inequality is proved in J. L. Vazquez, E. Zuazua (2000). Hence we can see that H 1 0 (Ω) ⊂ D(P 1/2 a(N) ) ⊂ H s (Ω) (s < 1). Therefore we can construct global weak solutions to (NLS)a on Ω by the energy methods.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
5634. Critical conditions of pressurized pipes
- Creator:
- Gajdoš, Ľubomír and Šperl, Martin
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- pressurized pipe, J-integral, C factor, and critical conditions
- Language:
- English
- Description:
- A single fracture-mechanics based method is described for assessing a part-through crack in the wall of a pipe subjected to internal pressure of liquid and/or gas. The method utilizes simple approximate expressions for determining the fracture parameters K, J, and employs these parameters to determine critical dimensions of crack on the basis of equality between the J-integral and the J-based fracture toughness of the pipe steel. The crack tip constraint is accounted by the so-called plastic constraint factor C, by which the uniaxial yield stress in the J. integral equation is multiplied. The results of the prediction of the fracture condition are verified by burst tests on test pipes. and Obsahuje seznam literatury
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5635. Critical responses of photosynthetic efficiency of goldspur apple tree to soil water variation in semiarid loess hilly area
- Creator:
- Zhang, S. Y., Zhang, G. C. , Gu, S. Y., Xia, J. B., and Zhao, J. K.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, critical efficiency, goldspur apple tree, loess hilly area, photosynthetic efficiency, and soil water content
- Language:
- Multiple languages
- Description:
- Goldspur apple (Malus pumila cv. Goldspur) is one of the main fruit trees planted in semiarid loess hilly areas. The photosynthetic efficiency in leaves of eight-year-old trees were studied under different soil water conditions with a Li-6400 portable photosynthesis system and a Li-Cor1600 portable steady state porometer in order to explore the effects of soil water stress on photosynthesis and the suitable soil water content (SWC) for water-saving irrigation of apple orchards. The results showed that the leaf net photosynthetic rate (P N), transpiration rate (E), water-use efficiency (WUE), stomatal conductance (gs), intercellular CO2 concentration (Ci), and stomatal limiting value (Ls) displayed different threshold responses to soil water variation. When SWC was within a range of about 60%-86% of field capacity (FC), PN and E were maintained in a relative steady state. At an elevated level but below 60% of FC, both PN and E decreased evidently with decreasing soil moisture. The SWC needed to support WUE in a relatively steady state and at a high level was in the range of about 50%-71% of FC. When SWC was less than 48% of FC, g s and Ls declined with decreasing soil moisture, while Ci increased rapidly. Based on the analysis of the stomatal limitation of photosynthesis using two criteria (Ci and Ls) suggested by Farquhar and Sharkey, it was implied that the predominant cause of restricting PN had changed from stomatal limitation to nonstomatal one under severe water stress. In terms of water-saving irrigation for enhancing water-use efficiency, it was concluded that in semiarid loess hilly areas, the suitable range of SWC for water-saving irrigation in goldspur apple orchards is in the range of about 50%-71% of FC, and the most severe degree of soil water stress tolerated for photosynthesis is about 48% of FC. and S. Y. Zhang ... [et al.].
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5636. Crop water supply and its relation to yield of spring wheat in the south of Russian plain
- Creator:
- Shumová, Nadezhda
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- soil water, crop yield, transpiration, Southern Russian Plains, pôdna voda, úroda, transpirácia, and Juhoruské nížiny
- Language:
- Slovak
- Description:
- The proposed method to estimate water supply of spring wheat crop is based on the ratio of the water amount extracted by plants under actual conditions of growth (transpiration) to cover needs for maximum (potential) yield (potential transpiration). Estimates of spatial, inter- and intra-annual water supply variability of the spring wheat crop in basic agricultural zones are given. Dependence of the spring wheat yield on water supply is presented. and Navrhnutá metóda určenia zásobovania porastu jarnej pšenice vodou je založená na určení pomeru množstva vody odobratého koreňmi rastlín (transpirácia) k potenciálnej transpirácii, ktorá je podmienkou maximálnej (potenciálnej) úrody. Práca obsahuje údaje o priestorovej, ročnej a medziročnej variabilite transpirácie jarnej pšenice v základných poľnohospodárskych oblastiach, ako aj závislosť úrod jarnej pšenice na zásobovaní porastu vodou (transpirácii).
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5637. Cross-talk between nitric oxide and HSP70 in the antihypotensive effect of adaptation to heat
- Creator:
- Malyshev, I. Yu., Bayda, L. A., Trifonov, A. I., Larionov, N. P., Kubrina, L. D., Mikoyan, V. D., Vanin, A. F., and Manukhina, E. B.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, oxid dusnatý, adaptace (biologie), hypotenze, nitrous oxide, adaptation (biology), hypotension, heat shock protein, heat shock, 14, and 612
- Language:
- English
- Description:
- In this work, we evaluated the effect of adaptation to heat on the fall of blood pressure (BP) induced by heat shock (HS) and the interrelation between nitric oxide (NO) and heat shock protein, HSP70. Experiments were carried out on Wistar rats. It was shown that HS resulted in a generalized and transient increase in NO production (the electron paramagnetic resonance method) and a fall of BP from 113± 3 to 88± 1 mm Hg (?<0.05). Adaptation to heat itself did not affect BP, but completely prevented the NO overproduction and hypotension induced by HS. The adaptation simultaneously increased the brain NO-synthase content and induced HSP70 synthesis (the Western blot analysis) in various organs. Both the antihypotensive effects of adaptation and HSP70 accumulation were completely prevented by L-NNA, an inhibitor of NO synthesis, or quercetin, an inhibitor of HSP70 synthesis. The data suggest that adaptation to heat stimulates NO synthesis and NO activates synthesis of HSP70. HSP70, which hampers NO overproduction, thus restricts the BP fall induced by heat shock., I. Yu. Malyshev, L.A. Bayda, A.I. Trifonov, N.P. Larionov, L.D. Kubrina, V.D. Mikoyan, A.F. Vanin, E.B. Manukhina., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5638. Crossed product of cyclic groups
- Creator:
- Agore, Ana-Loredana and Frățilă, Dragoş
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- cyclic groups, crossed product of groups, and Chinese Remainder Theorem
- Language:
- English
- Description:
- All crossed products of two cyclic groups are explicitly described using generators and relations. A necessary and sufficient condition for an extension of a group by a group to be a cyclic group is given.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
5639. Crowding-induced alterations in vascular system of Wistar-Kyoto rats: role of nitric oxide
- Creator:
- Iveta Bernátová, Angelika Púzserová, Jana Navarová, Csizmadiová, Z., and Michal Zeman
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie živočichů, stres (psychologie), adaptace (biologie), animal physiology, stress (psychology), adaptation (biology), vasorelaxation, corticosterone, 14, and 612
- Language:
- English
- Description:
- The aim of this study was to determine the effect of chronic crowding on the cardiovascular system of Wistar-Kyoto (WKY) rats. Rats were randomly divided into the control (480 cm2 per rat) or crowded (200 cm2 per rat) group for eight weeks. Body weight, blood pressure (BP), heart rate and plasma nitrate/nitrite levels of the crowded rats were not different from controls at the end of the experiment. Plasma corticosterone exhibited an increasing trend (5.7±1.8 vs. 12.6±3.7 ng/ml, p=0.08) while blood glucose was significantly reduced in the crowded rats in comparison with the controls. Nitric oxide (NO) synthase activity and nitrate/nitrite levels of the crowded rats were significantly elevated in the aorta by ∼80 % and ∼20 %, respectively, but unchanged in the left ventricle. Moreover, acetylcholine-induced relaxation was significantly increased in the crowded rats in both the femoral artery (61±5 % vs. 76±5 %, p<0.001) and mesenteric artery (51±6 % vs. 72±7 %, p<0.001). In conclusion, results suggest that chronic crowding may increase vasorelaxation and vascular NO production in normotensive rats. This may be considered as an adapting mechanism preventing the development of the stress-related elevation of BP. Additionally, results also suggest caution in the housing of rats because an inappropriate crowding may affect results of the experiment significantly., I. Bernátová, A. Púzserová, J. Navarová, Z. Csizmadiová, M. Zeman., and Obsahuje bibliografii a bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
5640. Crustacean-acanthocephalan interaction and host cell-mediated immunity: parasite encapsulation and melanization
- Creator:
- Dezfuli, Bahram Sayyaf, Simoni, Edi, Duclos, Laura, and Rossetti, Emanuele
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- Pomphorhynchus laevis, Echinogammarus stammeri, host immunity, and parasite melanization
- Language:
- English
- Description:
- Host-parasite interactions of Pomphorhynchus laevis (Müller, 1776) in naturally infected amphipod, Echinogammarus stammeri (Karaman), from the Brenta River (northern Italy) are described. A fully developed acanthocephalan larva occupies a large portion of an amphipod's haemocoelic space; thus, the parasite frequently induces displacement of host digestive tract and other internal organs. However, no apparent damage to the host's internal structures was observed. Within the haemocoel of E. stammeri, each larva of P. laevis is surrounded with a membranous layer, formed by microvilli, which maintains intimate contact with the amphipod's internal organs and haemocytes. Three types of circulatory haemocytes were identified based upon their distinct appearance: hyaline cell, semi-granular cell and granular cell. Echinogammarus stammeri haemocytes surrounded acanthocephalan larvae and in some instances a partially and/or totally melanized P. laevis larva was noticed. Interestingly, no melanized larvae were found in E. stammeri parasitized with other acanthocephalans namely Echinorhynchus truttae (Schrank, 1788), Polymorphus minutus (Goeze, 1782) and Acanthocephalus clavula (Dujardin, 1845).
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public