This article investigates the impacts of proper modeling of the wake effects and wind speed delays, between different wind turbines' rows, on the dynamic performance accuracy of the wind farms models. Three different modeling scenarios were compared to highlight the impacts of wake effects and wind speed time-delay models. In the first scenario, wind wake effect and time delay are ignored. Consequently, all wind turbines are assumed subjected to the same wind speed profile. The second scenario considers the wind wake (...) effect, and it was modeled by reducing the incident wind speed values by 0.5 m/s from one row to the next row facing the wind. The last scenario, the proposed model, used the wind wake effect model developed for wind turbines micrositting applications and considered the effect of the delay time between the wind speed profiles incident on the different wind turbines' rows. (shrink)

Fix 2 < n < ω. Let CA n denote the class of cylindric algebras of dimension n, and let RCA n denote the variety of representable CA n ’s. Let L n denote first-order logic restricted to the first n variables. Roughly, CA n, an instance of Boolean algebras with operators, is the algebraic counterpart of the syntax of L n, namely, its proof theory, while RCA n algebraically and geometrically represents the Tarskian semantics of L n. Unlike Boolean (...) algebras having a Stone representation theorem, RCA n ⊊ CA n. Using combinatorial game theory, we show that the existence of certain finite relation algebras RA, which are algebras whose domain consists of binary relations, implies that the celebrated Henkin omitting types theorem fails in a very strong sense for L n. Using special cases of such finite RA ’s, we recover the classical nonfinite axiomatizability results of Monk, Maddux, and Biro on RCA n and we re-prove Hirsch and Hodkinson’s result that the class of completely representable CA n ’s is not first-order definable. We show that if T is an L n countable theory that admits elimination of quantifiers, λ is a cardinal < 2 ℵ 0, and F = 〈 Γ i : i < λ 〉 is a family of complete nonprincipal types, then F can be omitted in an ordinary countable model of T. (shrink)

It is well-known that Ibn al-Salāh al-Shahrazūrī (d. 643/1245) has an important place in the field of hadith methodology. In this context, it is possible to see Ibn-al Salah’s influence in a large proportion of the hadith terminology. The fact that the term ḥasan was not substantially included in the hadith method studies before Ibn-al Salah and that this concept became widely known in the field after him led to study the contributions of al Salah on the subject of ḥasan (...) hadith and in this regard, his effect on the term ḥasan. As result it was found that authorities such as Shāfiʿī (d. 204/820), ʿAlī b. al-Madīnī (d. 234/848-49), Ahmad b. Hanbal (d. 241/855) used the concept of ḥasan in various meanings before al-Tirmidhī (d. 279/892) who, according to general acceptance, made the term ḥasan famous for its terminological use. However, it is possible to say that ʿAlī b. al-Madīnī was the first to use the terminological meaning of the concept ḥasan. Actually, the fact that Shafii’ used the term ḥasan isnād for an authentic hadith that al-Bukhārī (d. 256/870) and Muslim b. Ḥajjāj (d. 261/875) would later unanimously narrate, and Ahmad b. Hanbal used ḥasan as gharib, is evidence for the unsystematic use of the term in the early periods. Even though, thanks to al-Tirmidhī, an important place was opened for the concept in riwāya literature, there was no serious mention of the term in later hadith methodology. Therefore, it has been seen that hadith scholars considered the term ḥasan within the scope of ṣaḥīḥ or ḍaʻīf hadith, since they accepted the term as an intermediate concept, and for this reason they did not include the term ḥasan among the subjects of hadith methodology until Ibn al-Salāh. An examination of the argument, that one can act upon a ḍaʻīf hadith, would show that ḥasan hadith might have been interpreted within the scope of ḍaʻīf hadith. On the other hand, the fact that some scholars such as Mughulṭāy b. Qilīj (d. 762/1361) state that a hadith would be called ṣaḥīḥ if it is maqbūl with any presumption, and that there is no point in calling such a hadith ḥasan shows that the ḥasan hadith is considered within the scope of ṣaḥīḥ hadith. The fact that hadith methodology scholars did not mention ḥasan hadith before Ibn al-Salāh stems from the ambiguity of the subject. Contrary to his predecessors, Ibn al-Salāh tried to save the term ḥasan from its ambiguity by combining the different specifications put forward by al-Tirmidhī, al-Khaṭṭābī (d. 388/998), and Ibn al-Jawzī (d. 597/1201). The specifications and interpretations of the term presented by Ibn al-Salāh via his meticulous efforts, have also been adopted by his successors. The term ḥasan hadith has gained an important place in the literature of hadith methodology thanks to the views and definitions built on the descriptions and interpretations of Ibn al-Salāh. In this context, while there are those who agree with Ibn al-Salāh’s descriptions and evaluations of the term, there are also those who criticize his remarks on the subject. However, it has been seen that those who criticize Ibn al-Salāh, along with those who follow him, criticized him by following the path drawn by Ibn al-Salāh. Based on this and similar situations, it was concluded that not only the descriptions and comments that Ibn al-Salāh made, but also his style and methods of handling the subject gave direction to the studies on hadith methodology. In addition, it has been observed that the most compact description of the term ḥasan is put forward by Ibn Hajar and today’s studies are predicated on his description. Within this framework, after emphasizing that there are four degrees of maqbūl hadiths, Ibn Hajar defined the two fields, which were covered by two different descriptions of Ibn al-Salāh, as ḥasan li-zatih and lighairih by Ibn al-Ḥajar. (d. 852/1449) By doing so Ibn al-Ḥajar gave the final shape to the ḥasan hadith terms. He also captured the fundamental point where ḥasan hadith differs from the ṣaḥīḥ hadith because the basic point in question, which was not directly stated before, is a slight flaw in the narrator’s grip. At the end of the study, it was concluded that -as al-Dhahabi (d. 748/1348) also stated- it does not seem possible to determine a comprehensive rule that gathers ḥasan hadiths under a single description. Considering the historical context of the term ḥasan, it has been observed that the most effective description of the ḥasan hadith are the terms ḥasan li-zatih and ḥasan lighairih, which were put forward by Ibn Hajar by transforming the dual division mentioned by Ibn al-Salāh into a more understandable form. (shrink)

Contemporary society, according to Centore, is dominated by a post-modern philosophical world-view. Lacking until now, from the many works that have been written on post-modernism, is one that scrutinizes its fundamental assumptions and presuppositions. Being and Becoming attempts to fill this need by synthesizing the key developments in contemporary post-modernism. By taking the reader through the various historical periods and developments which have led to the current situation, Centore shows what is now taken for granted by the vast majority of (...) people is not necessary for either philosophical or theological reasons. (shrink)