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Start Over Data provider Academy of Sciences Library/Knihovna Akademie věd ČR Date Unknown

1064. 2-D water quality modelling of a drinking water reservoir

Creator:
Růžička, Martin, Hejzlar, Josef, Mikešová, Petra, and Cole, Thomas M.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
CE-QUAL-W2, coupled hydrodynamic-ecological model, dimictic stratified reservoir, sensitivity analysis, validation, sdružený hydrodynamicko-ekologický model, dimiktická stratifikovaná nádrž, citlivostní analýza, and validace
Language:
Slovak
Description:
Management of reservoirs for drinking water supply should be based on a thorough knowledge of water quality changes within variable conditions of hydrology, climate, nutrient loading and water storage. The two-dimensional longitudinal water quality model CE-QUAL-W2 was tested for its ability to predict concentrations of organic matter and trophic conditions in Rimov Reservoir, a small dimictic reservoir (volume 33,000,000 m3, maximum depth 43 m, hydraulic retention time 40 to 160 d) suffering from seasonally increased concentrations of humic substances and symptoms of eutrophication. The model was calibrated on two seasonal courses differing in hydrology and validated on a 1074 day period. The averages of absolute mean errors between simulated and measured vertical profiles of temperature, and concentrations of dissolved organic matter, dissolved oxygen and chlorophyll a in the validation run were 0.9 °C, 0.8 mg l-1, 1.2 mg l-1 and 0.008 mg l-1, respectively. Analysis of results and sensitivity analysis of modelling phytoplankton and phosphorus showed suitability of the mathematical description of their dynamics in the photic zone but not in the deeper layers. In spite of this partial problem, the model was found appropriate for the reliable predictions of water quality dynamics in Rimov Reservoir. and Hospodaření s vodou ve vodárenských nádržích by mělo být založeno na podrobné znalosti vlivu hydrologických, klimatických a limnologických veličin na kvalitu vody. Možnosti matematického modelování změn kvality vody byly testovány pro nádrž Římov na Malši za pomoci dvourozměrného modelu kvality vody CE-QUAL-W2. Model byl zkalibrován na dvou sezónních řadách dat pro hydrologicky různá období a poté byl uplatněn na 1074-denní řadě dat. Byly vyhodnoceny rozdíly mezi měřenými a simulovanými vertikálními profily teploty, koncentrací rozpuštěných organických látek, rozpuštěného kyslíku a chlorofylu. Tyto rozdíly vyjádřené jako velikost absolutní střední chyby byly 0,9 °C, 0,8 mg l-1 , 1,2 mg l-1 a 0.008 mg l-1 . Analýza získaných výsledků a citlivostní analýza modelu ukazují dobrou shodu mezi naměřenou a simulovanou dynamikou zmíněných veličin v eufotické zóně, v nižších a tmavších vrstvách nádrže dochází k nárůstu odchylek modelu od reality. Přes tyto dílčí problémy byl model shledán jako užitečný a nenahraditelný pomocník při úlohách řešících dopad vnějších vlivů na kvalitu vody v nádrži.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1065. 2-factors in claw-free graphs with locally disconnected vertices

Creator:
An, Mingqiang, Xiong, Liming, and Tian, Runli
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
claw-free graph, 2-factor, closure, locally disconnected vertex, and singular edge
Language:
English
Description:
An edge of $G$ is singular if it does not lie on any triangle of $G$; otherwise, it is non-singular. A vertex $u$ of a graph $G$ is called locally connected if the induced subgraph $G[N(u)]$ by its neighborhood is connected; otherwise, it is called locally disconnected. In this paper, we prove that if a connected claw-free graph $G$ of order at least three satisfies the following two conditions: (i) for each locally disconnected vertex $v$ of degree at least $3$ in $G,$ there is a nonnegative integer $s$ such that $v$ lies on an induced cycle of length at least $4$ with at most $s$ non-singular edges and with at least $s-5$ locally connected vertices; (ii) for each locally disconnected vertex $v$ of degree $2$ in $G,$ there is a nonnegative integer $s$ such that $v$ lies on an induced cycle $C$ with at most $s$ non-singular edges and with at least $s-3$ locally connected vertices and such that $G[V (C)\cap V_{2} (G)]$ is a path or a cycle, then $G$ has a 2-factor, and it is the best possible in some sense. This result generalizes two known results in Faudree, Faudree and Ryjáček (2008) and in Ryjáček, Xiong and Yoshimoto (2010).
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

1066. 2-meter telescope devices: coudé slit spectrograph and HEROS

Creator:
Šlechta, Miroslav and Škoda, Petr
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
spectroscopy, coudé slit spectrograph, and fiber-fed echelle spectrograph HEROS
Language:
Czech
Description:
The Ondřejov 2-meter Telescope is used either in the Cassegrain or in the coudé focus; the primary focus is not used. The primary goal is the spectroscopy. Nowadays, the Cassegrain focus is equipped with the fiber-fed echelle spectrograph HEROS owned by the Landessternwarte Heidelberg-Konigstuhl. The coudé focus is equipped with the slit spectrograph. Usually, the slit coudé spectrograph is being used in winter due to the lower sensitivity to the weather condition (seeing).
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

1067. 2-normalization of lattices

Creator:
Chajda, Ivan, Cheng, W., and Wismath, S. L.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
2-normal identities, lattices, 2-normalized lattice, and 3-level inflation of a lattice
Language:
English
Description:
Let $\tau $ be a type of algebras. A valuation of terms of type $\tau $ is a function $v$ assigning to each term $t$ of type $\tau $ a value $v(t) \geq 0$. For $k \geq 1$, an identity $s \approx t$ of type $\tau $ is said to be $k$-normal (with respect to valuation $v$) if either $s = t$ or both $s$ and $t$ have value $\geq k$. Taking $k = 1$ with respect to the usual depth valuation of terms gives the well-known property of normality of identities. A variety is called $k$-normal (with respect to the valuation $v$) if all its identities are $k$-normal. For any variety $V$, there is a least $k$-normal variety $N_k(V)$ containing $V$, namely the variety determined by the set of all $k$-normal identities of $V$. The concept of $k$-normalization was introduced by K. Denecke and S. L. Wismath in their paper (Algebra Univers., 50, 2003, pp.107-128) and an algebraic characterization of the elements of $N_k(V)$ in terms of the algebras in $V$ was given in (Algebra Univers., 51, 2004, pp. 395--409). In this paper we study the algebras of the variety $N_2(V)$ where $V$ is the type $(2,2)$ variety $L$ of lattices and our valuation is the usual depth valuation of terms. We introduce a construction called the {\it $3$-level inflation} of a lattice, and use the order-theoretic properties of lattices to show that the variety $N_2(L)$ is precisely the class of all $3$-level inflations of lattices. We also produce a finite equational basis for the variety $N_2(L)$.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

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