In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred to as the velocity where a bed starts sliding or the velocity above which there is no stationary bed or sliding bed. Others use the velocity where the hydraulic gradient is at a minimum, because of the minimum energy consumption. Most models from literature are one term one equation models, based on the idea that the critical velocity can be explained that way. Here the following definition is used: The critical velocity is the line speed below which there may be either a stationary bed or a sliding bed, depending on the particle diameter and the pipe diameter, but above which no bed (stationary or sliding) exists, the Limit Deposit Velocity (LDV). The way of determining the LDV depends on the particle size, where 5 regions are distinguished. These regions for sand and gravel are roughly; very small particles up to 0.014-0.040 mm (d < δv), small particles from δv-0.2 mm, medium particles in a transition region from 0.2-2.00 mm, large particles > 2 mm and very large particles > 0.015·Dp. The lower limit of the LDV is the transition between a sliding bed and heterogeneous transport. The new model is partly based on physics and correlates well with experiments from literature.
The paper deals with a type of whole and part that can be found in Aquinas’ work and to which no attention has been paid so far. This type of whole and part can be called metaphysical whole and metaphysical part, respectively. In the paper, metaphysical whole and part are put forth on the problem of the logical and metaphysical structure of a common nature., Příspěvek pojednává o typu celku a jeho části, které lze nalézt v díle Akvinského a na které dosud nebyla věnována pozornost. Tento typ celku a části lze nazvat metafyzickou celou a metafyzickou částí. V příspěvku jsou metafyzický celek a jeho část uvedeny na téma logické a metafyzické struktury běžné povahy., and David Svoboda
Contrary to proponents’ claims, methodological naturalism is not metaphysically neutral. Consequently, its acceptance as a practice requires justification. Unfortunately for its advocates, attempts to justify it are failures. It cannot be defended as a definition, or a self-imposed limitation, of science, nor, more modestly, as an inductively justified commitment to natural causes. As a practice, it functions not to further scientific investigation, but rather to impose an explanatory straitjacket., Na rozdíl od tvrzení zastánců není metodologický naturalismus metafyzicky neutrální. Proto jeho přijetí jako praxe vyžaduje odůvodnění. Bohužel pro své obhájce jsou pokusy ospravedlnit to neúspěchy. Nelze ji obhajovat jako definici nebo samoobmedzení vědy, ani skromněji jako indukčně odůvodněný závazek k přirozeným příčinám. Jako praxe, to funguje ne k dalšímu vědeckému zkoumání, ale poněkud uložit vysvětlující kazajku., and Robert A. Larmer
While prototypical uses of slurs express contempt for targets, some reclaimed uses are associated with positive evaluations. This practice may raise concerns. I anticipate this criticism in what I dub the Warrant Argument (WA) and then defend the legitimacy of this kind of reclamation. For the WA, standard pejorative uses of slurs are problematic for assuming unwarranted connections between descriptive properties (e.g., being gay) and value judgements (e.g., being worthy of contempt). When reclaimed uses of slurs express a positive evaluation of their targets—the WA goes—reclamation fails to challenge the unwarranted link between descriptive properties and value judgements, and merely reverses the evaluation polarity from negative to positive. So, the WA concludes, reclaimed uses of slurs evaluating targets positively for belonging to a certain group make a similar moral error as derogatory uses of slurs (sections 2-3). The WA could lead us to condemn reclamation. To resist this conclusion, I draw a parallel with affirmative action, arguing that it can be morally permissible to balance an existing form of injustice by temporarily introducing a countervailing mechanism that prima facie seems to violate the norm of equality: even if the WA were right, it wouldn’t constitute an argument against the moral permissibility of reclamation in the case of most slurs (section 4). This line of argument in defense of pride reclamation may also serve to debunk the myths of reverse racism and reverse sexism (section 5).
In this paper I will propose that the unpalatable consequences of narrow-scope principles are not avoided by altering the scope of the principle but by changing the kind of conditional. I argue that a counterfactual conditional should do the trick and that the rational requirement of modus ponens can be understood as something like a ''Ramsey test'' on this conditional., V tomto příspěvku navrhnu, aby nedocházelo k nežádoucím důsledkům zásad úzkého rozsahu tím, že se změní rozsah této zásady, ale změnou druhu podmíněnosti. Domnívám se, že kontrafaktuální podmíněnost by měla dělat trik a že racionální požadavek modus ponens může být chápán jako něco jako ,,Ramseyho test'' na tomto podmíněném., and David Botting
The unique relation between logic and truth (protorelation) is crucial for understanding Fregean conception of logic. Frege has an insight that the nature of logic resides in the ''truth'', which he finally locates in the assertoric-force of a sentence. Though Frege admits that assertoric-force is ineffable in ordinary language, he coins in his conceptual notation for such a force a much-disputed sign, i.e., judgment-stroke. In this paper, I will try to demonstrate that judgment-stroke is not adequate for the task its inventor has assigned to it. Accordingly, it is misconceived and inconducive to clarify Frege’s vague insight into the protorelation. The mistake of judgment-stroke for the sign of assertoric-force has its root in Frege’s ignorance of the significant difference between ''judgment'' and assertion'', which will be elucidated at length in the light of Husserl’s theory of ''doxic-modification''. In the end, based on a further elucidation of the activity of assertion, I will advance a tentative interpretation of the vague insight Frege has concerning the protorelation., Jedinečný vztah mezi logikou a pravdou (protorelace) je klíčový pro pochopení logiky Fregean. Frege má pochopení, že podstata logiky spočívá v ,,pravdě'', kterou nakonec nalezne v přísloví věty. Ačkoli Frege připustí, že assertoric-síla je nevýslovná v obyčejném jazyce, on mince v jeho pojmovém zápisu pro takovou sílu hodně-sporné znamení, tj., Rozsudek-mrtvice. V tomto příspěvku se pokusím prokázat, že rozsudek-úder není vhodný pro úkol, který mu jeho vynálezce přidělil. V souladu s tím je nepochopitelné a nevhodné vyjasnit Fregeův nejasný pohled na protorelaci. Chyba úsudku-mrtvice pro znamení assertoric-síla má jeho kořen ve Fregeově neznalosti významného rozdílu mezi ,,rozsudkem a tvrzením '', který bude podrobně objasněn ve světle Husserlovy teorie ,,doxické modifikace''. V závěru, na základě dalšího objasnění činnosti tvrzení, budu postupovat předběžně ve výkladu neurčitého náhledu Fregeho týkajícího se protorelace., and Gao Song
Current philosophical debates about perception have largely ignored questions concerning the ontological structure of perceptual experience, so as to focus on its intentional and phenomenological character. To illustrate and put pressure on this tendency, I revisit the controversy between doxastic views of perception and Gareth Evans’s objection from over-intellectualization. I suggest that classic versions of the doxastic view are to a good extent driven by an ontological characterization of perceptual attitudes as nonfactive states or dispositions, not by a cognitively complex picture of perceptual content. Conceived along these lines, the doxastic view unveils an ontologically significant story of perceptual experience for at least two reasons: on the one hand, that characterization avoids the line of reasoning leading up to sense-datum theories of perception; and, on the other, it bears on recent discussions about the temporal structure of perceptual experience. Although I do not endorse the doxastic view, my goal is to highlight the importance of the relatively neglected ontological motivations thus driving that kind of account.
Personites are shorter-lived, person-like things that extend across part of a person’s life. Their existence follows from the standard perdurance view of persons. Johnston argues that it has bizarre moral consequences. For example, it renders morally problematic spending time learning a difficult language in anticipation of going abroad. The crucial thought is that if persons have moral status so do personites. Johnston argues for this claim. Kaiserman responds, on behalf of stage theory, that this only works on a perdurantist account. This is a conservative response to the problem. It seeks to show that retaining the ontology of perdurantism one can resolve the difficulty by a semantic change. I show that the personite problem can be reworked as an argument against stage theorists. The stage theorist can respond by rejecting an assumption of the reasoning. But if it is acceptable for him to do so the perdurantist can reject this assumption too, which is enough by itself to block Johnston’s argument. Thus, for all it helps with the personite problem, stage theorists might as well be perdurantists.
People who do not act on their judgments regarding what they ought to do-their practical judgments-are often considered weak-willed, especially when the judgment is made at a time when the act it favors is plainly possible. Is this a kind of practical irrationality, perhaps due to an incoherence between practical reason, which should guide intention and action, and behavior that fails to conform to a guiding directive? More generally, do normative beliefs with the same kind of self-directive content as practical judgments possess the same sort of rational authority, if indeed they must have any such authority? At least since Aristotle, weak-willed action has often been considered irrational. This paper indicates why that view is plausible, but also why it is too strong. The paper shows how the practical authority of normative judgments can be overridden and why, on the theory of rational action suggested by analysis of such cases, certain initially plausible action-guiding principles are too strong. The concluding part of the paper briefly indicates how that theory can do justice to the analogy between practical and theoretical reason and to the essential connection between the two., Lidé, kteří nečiní podle svých úsudků ohledně toho, co mají dělat - jejich praktických úsudků - jsou často považováni za slabé, zejména když je rozsudek učiněn v době, kdy je čin, který upřednostňuje, jasně možný. Je to taková praktická iracionalita, možná kvůli nesouladu mezi praktickým důvodem, který by měl vést záměr a jednání, a chování, které neodpovídá hlavní směrnici? Obecněji řečeno, mají normativní přesvědčení se stejným druhem sebeobsahu, jako jsou praktická rozhodnutí, stejný druh racionální autority, pokud skutečně musí mít takovou autoritu? Přinejmenším protože Aristotle, slabě-chtěl akce často byl považován za iracionální. Tento článek ukazuje, proč je tento pohled věrohodný, ale také proč je příliš silný. Příspěvek ukazuje, jak může být praktická autorita normativních úsudků potlačena a proč na teorii racionálních kroků navrhovaných analýzou takových případů jsou některé z původně věrohodných principů, které vedou k akci, příliš silné. Závěrečná část práce stručně naznačuje, jak tato teorie může spravedlivě odpovídat analogii mezi praktickým a teoretickým důvodem a podstatným spojením mezi nimi., and Robert Audi