Non-Destructive Investigation of Bulk Residual Stress in Automobile Brake Pads with its Service Life

Automobile brake systems transform kinetic energy into heat for the purpose of speed control. During this operation, rapid heating and cooling cycles cause the formation of residual stress in the brake pad backing plate. In this study, the relation between residual stress magnitude and the operation period is investigated to predict the service life of brake pads. Residual stresses are calculated related to longitudinal ultrasonic wave velocity variations which are measured non-destructively using cost effective and accurate immersion ultrasonic technique. Finally, a mathematical model is developed to predict residual stress in brake pad backing plates related to operation period

Logicality of second-order logic: A critical inquiry on the related debatesİkinci seviye mantığın mantıksallığı: İlgili tartışmalar üzerine eleştirel bir değerlendirme

Being the pioneer of modern logic, Frege, with his quantification theory, was the pioneer of not only first-order logic, but also second-order logic. But today, as it may be seen from the recent pedagogical works clearly, learning modern logic has become almost equivalent to learning first-order logic. In the other words, first-order logic appears as the most natural, paradigmatic and central system of logic. However second-order logic either doesn’t appear in recent pedagogical works or appears as an interesting detail of the history of logic. Moreover, today even the logicality of second-order logic has become controversial. In this controversy, two of the criticisms against the logicality of second-order logic have become more apparent than the others: (1) the logical incompleteness criticism, and (2) the ontological commitments criticism. In this study, these two criticisms, which was put forward as a justification of the claim that second order logic is not a purely-logical system, and several responses to these criticisms are tried to be clarified in a simple and untechnical manner. Additionally it is argued that, while these two criticisms are strong and justified, several responses to these criticisms are weak. ÖzetModern mantığın öncüsü Frege niceleme kuramıyla, yalnızca birinci seviye mantığın değil, aynı zamanda ikinci seviye mantığın da öncüsüydü. Ancak günümüz pedagojik yapıtlarında da açıkça görülebileceği gibi bugün modern mantığı öğrenmek bunlardan birinci seviye mantığı öğrenmekle eşdeğer hale gelmiştir. Diğer bir deyişle birinci seviye mantık, mantığın en doğal, paradigmatik ve merkezi sistemi olarak kendini göstermektedir. Diğer taraftan ikinci seviye mantık ise günümüz pedagojik yapıtlarında ya yer almamakta ya da bu yapıtlarda mantık tarihinin ilginç bir ayrıntısı olarak yer almaktadır. Dahası bugün ikinci seviye mantığın mantıksallığı dahi tartışmalı hale gelmiştir. Bu tartışmalarda ikinci seviye mantığın mantıksallığına getirilen eleştirilerden ikisi diğerlerine göre daha belirgin hale gelmiştir. (1) Mantık sistemsel eksiklik eleştirisi ve (2) gizli ontolojik kabuller eleştirisi. Bu çalışmada ikinci seviye mantığın saf-mantıksal bir sistem olmadığı iddiasına gerekçe olarak ileri sürülen bu iki eleştiri ve bu eleştirilere getirilen çeşitli yanıtlar, basit ve teknik olmayan bir dille açık kılınmaya çalışılmıştır. Ek olarak bu iki eleştirinin güçlü ve haklı eleştiriler olduğu ve bu eleştirilere getirilen çeşitli yanıtların ise güçsüz olduğu savunulmuştur

Designed-in molecular interactions lead to superior thermo-mechanical properties in nanocomposites

The effect of the nanofiller chemistry on the mechanical behaviour of thermoset polymer matrix nanocomposites is investigated. The interaction between a crosslinked polymer resin and the reinforcing nanofibers driven by their chemistry is revealed by molecular dynamics simulations. Specifically, crosslinked network systems of neat epoxy and epoxy-P(St-co-GMA) are modeled to discuss the effect of various molecular interactions as a function of temperature on a molecular basis. At 433 K, incorporation of single molecule of bonded P(St-co-GMA) and nonbonded P(St-co-GMA) lead to increase in Young’s modulus by 10% and 6%, respectively, compared to neat epoxy system

Taylor and His Scientific Management System: Legendary Narratives and ‘Scientific’ Evaluations

Frederick W. Taylor is seen as the pioneer, even founder, or father of management science, and the scientific management system he developed is taught almost everywhere in the world under the name of Taylorism. However, while this is done, scientific evaluation of Taylor’s studies towards developing the scientific management system is rarely made under the consideration of the period he lived, original data, and sources. With this study, to better understand how and under what conditions the scientific management system spreading as Taylorism was developed, we seek to evaluate the research and the studies done by Taylor in terms of originality, accuracy and consistency based on the accessible electronic archives, correspondences, and academic literature. The evaluations made in this regard lead to an opinion that it would be more appropriate and useful to approach Taylor’s scientific management studies with caution in terms of originality, accuracy, and consistency, at least to conduct further examinations and research concerning these issues