The local scour around bridge piers influences their stabilities and plays a key role in the bridge failures. The estimation of the maximum possible scour depth around bridge piers is an important step in the design of the bridge pier foundations. In this study, the temporal evolution of local scour depths as well as the equilibrium scour depths were analyzed.
The experiments were carried out in a rectangular flume by using uniform sediment with median diameter of 3.5 mm and geometric standard deviation of 1.4. The diameters of the tested circular bridge piers were 40 mm, 80 mm, 150 mm and 200 mm. The flow and scour depths were determined by ultrasonic sensors. The experiments were realized in clear water conditions with various constant flow rates.
The experimental findings were compared with those calculated from some empirical equations existing in the literature. A new empirical relation involving the flow intensity, the relative water depth and the dimensionless time is also introduced. The advantage of this proposed relation is that the only parameter requiring the calculation is the critical velocity, other parameters being known geometric and hydraulic parameters. The performance of this relation was tested by using experimental data available in the literature, and a satisfactory compatibility was revealed between the experimental and numerical results.
The expressions sufficient condition and necessary condition are frequently used in various areas in sciences (like mathematics, logic, philosophy, natural sciences and social sciences) as well as in everyday usage; therefore, they might be taken as expressing well defined notions which should not lead to any serious misunderstandings when used. According to the widely accepted definitions of both concepts, the concept of sufficient condition and that of necessary condition imply their symmetry (conversion): if one thing poses a sufficient condition to another thing, the latter is a necessary condition for the former; however, this symmetry is hardly intuitive and it is refused by many scholars. Given the analyses of practical examples and a symmetry concept defence test, one may conclude that this view is unfounded. As a result, the definitions of the two notions are not determined enough and so is the question whether there is just a single pair of the notions or whether there are more of them., Výrazy dostatečná podmínka a nezbytná podmínka jsou často používány v různých oblastech vědy (např. Matematika, logika, filosofie, přírodní vědy a společenské vědy) i v každodenním používání; proto mohou být považovány za vyjádření dobře definovaných pojmů, které by při použití neměly vést k vážným nedorozuměním. Podle široce přijímaných definic obou pojmů, pojem dostatečné podmínky a podmínky nezbytné podmínky znamenají jejich symetrii (konverzi): pokud jedna věc představuje dostatečnou podmínku pro jinou věc, ta druhá je nezbytnou podmínkou pro druhou věc; nicméně, tato symetrie je stěží intuitivní a to je odmítnuto mnoha učenci. Vzhledem k analýzám praktických příkladů a obrannému testu koncepce symetrie lze konstatovat, že tento názor není opodstatněný. Jako výsledek,, and František Gahér
The study presents F. Suárez’s theory of the principles of sensation in the context of medieval (Averroes, John of Jandun) and renaissance philosophy (Nifo, Cajetan). It proceeds in five steps. First, it considers Suárez’s ontology of sensory cognitive act. Second, it treats Suárez’s theory of the formation of sensible species. Third, it presents Suárez’s ontology of sensible species. Fourth, it exposes Suárez’s theory of the efficient causes of the sensory cognitive act. In conclusion, the author states that Suárez’s theory, compared to the doctrines of Aquinas and Thomists, constitutes the significant historical shift from cognitive passivism to cognitive activism mirroring the Zeitgeist of the Renaissance philosophy without abandoning the basic tenets of the traditional Aristotelian – scholastic philosophy., Studie prezentuje teorii F. Suáreze o principech vnímání v kontextu středověkých (Averroes, John of Jandun) a renesanční filosofie (Nifo, Cajetan). Postupuje v pěti krocích. Za prvé považuje Suárezovu ontologii smyslového kognitivního aktu. Za druhé, jedná se o Suárezovu teorii utváření rozumných druhů. Za třetí, prezentuje Suárezovu ontologii rozumných druhů. Za čtvrté, odhaluje Suárezovu teorii efektivních příčin smyslového kognitivního aktu. V závěru autor uvádí, že Suárez teorie, ve srovnání s učením Tomáše Akvinského a Thomists, představuje významný historický posun od kognitivní passivism na kognitivní aktivismu zrcadlení na Zeitgeist renesančního filozofie aniž bychom opustili základní zásady tradiční aristotelské - scholastické filozofie., and Daniel Heider
Frege argues that considering Socrates as an object in the proposition “Socrates exists” raises two problems. First, this proposition would be uninformative. Second, its negation entails a contradiction. Attempting to solve these problems, Frege claims that Socrates is representing the concept of a man whose name is Socrates. Therefore, existence is a second-order concept. This paper surveys the main modern theories about the types of existence, in order to find another response to Frege’s problems. For, if Socrates’ existence differs from the type that “exists” implies, “Socrates exists” is informative and its negation is not a contradiction. At last, this paper argues for an idea, in which “existence” is not a concept or property. Existence is the principle of the objects. So, “Socrates exists” is in fact “the existence is Socrates,” and “Socrates does not exist” is “there is no existence that be Socrates.” This idea could be an alternative for responding to Frege’s problems.
This paper focuses on three theories of personal identity that incorporate the idea that personal identity is the result of a person’s adopting certain attitudes towards certain mental states and actions. I call these theories subjective theories of personal identity. I argue that it is not clear what the proponents of these theories mean by “personal identity”. On standard theories, such as animalism or psychological theories, the term “personal identity” refers to the numerical identity of persons and its analysis provides the persistence conditions for persons. I argue that if the subjective theories purport to provide a criterion of numerical personal identity, they fail. A different interpretation may suggest that they purport to provide a non-numerical type of identity for the purpose of providing plausible analyses of certain identity-related practical concerns. I argue that the criteria the subjective theories provide fail to capture several of the identity-related concerns. As a result, this interpretation must be rejected as well., Tato práce se zaměřuje na tři teorie osobní identity, které zahrnují myšlenku, že osobní identita je výsledkem toho, že člověk přijímá určité postoje k určitým duševním stavům a činnostem. Tyto teorie nazývám subjektivními teoriemi osobní identity. Tvrdím, že není jasné, co zastánci těchto teorií znamenají „osobní identitou“. Na standardních teoriích, jako jsou zvířecí nebo psychologické teorie, se termín „osobní identita“ vztahuje na numerickou identitu osob a její analýza poskytuje podmínky vytrvalosti pro osoby. Tvrdím, že pokud subjektivní teorie mají za cíl poskytnout kritérium numerické osobní identity, neuspějí. Jiný výklad může naznačovat, že mají za cíl poskytnout nečíselný typ identity za účelem poskytnutí věrohodných analýz určitých praktických problémů souvisejících s identitou. Tvrdím, že kritéria subjektivních teorií nedokážou zachytit několik problémů souvisejících s identitou. V důsledku toho musí být tento výklad rovněž zamítnut., and Radim Bělohrad
The lateral saturated hydraulic conductivity, Ks,l, is the soil property that mostly governs subsurface flow in
hillslopes. Determinations of Ks,l at the hillslope scale are expected to yield valuable information for interpreting and
modeling hydrological processes since soil heterogeneities are functionally averaged in this case. However, these data
are rare since the experiments are quite difficult and costly. In this investigation, that was carried out in Sardinia (Italy),
large-scale determinations of Ks,l were done in two adjacent hillslopes covered by a Mediterranean maquis and grass, respectively,
with the following objectives: i) to evaluate the effect of land use change on Ks,l, and ii) to compare estimates
of Ks,l obtained under natural and artificial rainfall conditions. Higher Ks,l values were obtained under the maquis than in
the grassed soil since the soil macropore network was better connected in the maquis soil. The lateral conductivity increased
sharply close to the soil surface. The sharp increase of Ks,l started at a larger depth for the maquis soil than the
grassed one. The Ks,l values estimated during artificial rainfall experiments agreed with those obtained during the natural
rainfall periods. For the grassed site, it was possible to detect a stabilization of Ks,l in the upper soil layer, suggesting that
flow transport capacity of the soil pore system did not increase indefinitely. This study highlighted the importance of the
experimental determination of Ks,l at the hillslope scale for subsurface modeling, and also as a benchmark for developing
appropriate sampling methodologies based on near-point estimation of Ks,l.
The aim of the paper is to investigate, from the point of view of philosophy of science and philosophy of social science, the turn in the ape language project as accomplished in the works of Sue Savage- Rumbaugh and her collaborators. In this project took place a highly interesting turn from the orientation of research on natural sciences to that on humanities. We shall analyze all the relevant works of Savage-Rumbaugh from the point of view of the two central levels of ALP: its scientific level and the methodological level., Cílem příspěvku je z hlediska filosofie vědy a filosofie společenských věd zkoumat obrat v projektu lidoopského jazyka, který byl realizován v dílech Sue Savage-Rumbaugh a jejích spolupracovníků. V tomto projektu se odehrál velmi zajímavý obrat od orientace výzkumu přírodních věd na humanitní vědy. Budeme analyzovat všechna relevantní díla Savage-Rumbaugh z hlediska dvou ústředních úrovní ALP: jeho vědecké úrovně a metodické úrovně., and Igor Hanzel
In the Baixo Vouga region of north-central Portugal, forests occupy half of the territory, of which two thirds are Eucalypts plantations. The hydrological implications of this large-scale introduction of eucalypt are unknown and the aim of this exploratory study, realized in the Caramulo Mountains, was to describe overland flow (OLF), subsurface flow (SSF) and stream flow (Q) in a catchment dominated by Eucalyptus plantations. The main conclusions are that annual OLF rate is low, spatially heterogeneous between 0.1% and 6% and concentrated during the wet season as saturation excess, particularly as return flow. Infiltration-excess OLF due to the strong soil water repellence (SWR) is dominant during dry season, but produces residual runoff amount. SSF is the principal mechanism of runoff formation. It originates from matrix flow and pipe flow at the soil-bedrock interface, principally during the wet season. Matrix flow is correlated with soil moisture (SM) content, with a threshold of 25 %. Pipe flow starts with saturation of soil bottom but without saturation of the entire soil profile, due to a large network of macropores. Stream flow response is highly correlated with matrix flow behaviour in timing and intensity. SWR induces a very patchy moistening of the soil, concentrates the fluxes and accelerates them almost 100 times greater than normal percolation of the water in the matrix.
Wolf proposes supererogation as a solution for curbing the exaggerated demands of morality. Adopting supererogation is supposed to prevent us from considering that all morally good deeds are obligatory. Supererogation, indeed, makes some morally good deeds merely optional, saving the agent from the requirement of behaving as much as possible like a Moral Saint. But I argue that Wolf cannot use supererogation in service of her overall project, for two reasons. First, because implied in the concept of supererogation is that going beyond duty adds to our humanity rather than detract from it (as Wolf argues). Secondly, after analyzing attempts to acclimatize supererogation in other theoretical frameworks, I conclude that supererogation can limit morality’s claims only if Wolf’s reasons of “individual perfection” can defeat moral reasons. I argue that a common scale of evaluation between moral and non-moral reasons is needed for their comparison, but Wolf explicitly rejects this way out.
Inland waters are known to be laden with high levels of suspended particulate matter (SPM). Remotely sensed data have been shown to provide a true synoptic view of SPM over vast areas. However, as to date, there is no universal technique that would be capable of retrieving SPM concentrations without a complete reliance on time-consuming and costly ground measurements or a priori knowledge of inherent optical properties of water-borne constituents. The goal of this paper is to present a novel approach making use of the synergy found between the reflectance in the visual domain (~ 400-700 nm) with the near-infrared portion of the spectrum (~ 700-900 nm). The paper begins with a brief discourse of how the shape and spectral dependence of reflectance is determined by high concentrations of SPM. A modeled example is presented to mimic real-world conditions in fluvial systems, with specific absorption and scattering coefficients of the virtual optically active constituents taken from the literature. Using an optical model, we show that in the visual spectral domain (~ 400-700 nm) the water-leaving radiance responds to increasing SPM (0-100 g m-3) in a non-linear manner. Contrarily to the visual spectra, reflectance in the near infrared domain (~ 700-900 nm) appears to be almost linearly related to a broad range of SPM concentrations. To reduce the number of parameters, the reflectance function (optical model) was approximated with a previously experimentally verified exponential equation (Schiebe et al., 1992: Remote sensing of suspended sediments: the Lake Chicot, Arkansas project, Int. J. Remote Sensing, 13, 8, 1487-1509). The SPM term in Schiebe’s equation was expressed as a linear function of top-of-atmosphere reflectance. This made it possible to calibrate the reflectance in the visual domain by reflectance values from the near-IR portion of the spectrum. The possibility to retrieve SPM concentrations from only remote sensing data without any auxiliary ground mea-surements is tested on a Landsat ETM + scene acquired over a reservoir with moderately turbid water with SPM concentrations between 15-70 g m-3. The retrieved concentrations (on average) differ from in-situ measurement by ~ 10.5 g m-3. and Cieľom príspevku je prezentovať alternatívne spracovanie satelitných snímok na odhad koncentrácie suspendovaných sedimentov vo vodných útvaroch. Prvá časť článku sa venuje teórii a fyzikálnej podstate reflektancie a vplyvu prirodzene sa vyskytujúcich opticky aktívnych prvkov vo vode (suspendované sedimenty, pigmenty a rozpustené látky) na reflektanciu snímanú prostriedkami diaľkového prieskumu Zeme. Na modelovom príklade sme ukázali, že so zvyšovaním koncentrácie suspendovaných látok dochádza k saturácii signálu reflektancie.V druhej časti príspevku sme opísali spôsob využitia nelineárnosti vzťahu medzi reflektanciu vo viditeľnej časti (~ 400-700), a kvázi-linearitov v infračervenej časti (~ 700-900 nm) elektromegnetického spektra a koncentrácie suspendovaných sedimentov. Optimalizáciou tohto nelineárneho vzťahu sme odhadli koncentrácie suspendovaných sedimentov pre zdrž Hrušov pri Bratislave s RMSE 10.5 g m-3.