System identification application using Hammerstein model

Generally, memoryless polynomial nonlinear model for nonlinear part and finite impulse response (FIR) model or infinite impulse response model for linear part are preferred in Hammerstein models in literature. In this paper, system identification applications of Hammerstein model that is cascade of nonlinear second order volterra and linear FIR model are studied. Recursive least square algorithm is used to identify the proposed Hammerstein model parameters. Furthermore, the results are compared to identify the success of proposed Hammerstein model and different types of models.     

An Intelligent Methodology for Railways Monitoring Using Ultrasonic Guided Waves

It is far from trivial to inspect railways for defections. In particular, for the foot area of the rail non destructive testing methods are known to be difficult to apply. In this paper, an ultrasonic guided wave method is considered along with classification methods for automated rail foot defect detection. In effect, given a set of gathered ultrasonic signals, multiple features are extracted from time-, frequency- and time–frequency domains. Next, a robust feature selection method is performed, to collect a small set of complementary features. The classification task is accomplished by means of a kernel-based support vector machine. To demonstrate the performance capabilities of our approach, an extensive experimental setup is designed under representative environmental and operational conditions. The sensitivity and the resolution of the proposed defect detection system are reported. A study on the influence of rail fastening on the proposed method is also reported where robust defect detection rates, greater than 93 %, are achieved assuming that a compact feature subset is considered. However, it is evident in experiments that even in the case of large defects, changes in the environmental conditions (temperature and humidity) increase the interpretation of the acquired signals, thus making the detection task more difficult.     

Chiral Calix[4]arenes-Bearing Prolinamide Functionality as Organocatalyst for Asymmetric Direct Aldol Reactions in Water

The chiral calix[4]arene derivative (6) bearing an L-prolinamido group has been designed and proved to be a water compatible efficient organocatalysts for a direct enantioselective aldol reaction. Compound 6 catalyzes the aldol reaction of cyclohexanone and a variety of aromatic aldehydes yielding anti-aldol products in high yield with enantioselectivities of up to 93% and diastereoselectivity of up to 95:5.     

Prediction of interfacial crack path: a direct boundary integral approach and experimental study

This paper presents the development of a higher-order direct boundary integral-displacement discontinuity method for crack propagation in layered elastic materials. The method is based on the dual boundary integral equations of linear elasticity which are solved by means of a quadratic boundary element formulation. The analytical solution for a point force within a bonded half-plane region is used to derive the kernel functions of the boundary integral equations. Square-root displacement-discontinuity elements are used to model the crack tips, and stress intensity factors may be computed using the numerically predicted values of the displacement discontinuity components at the midpoints of these crack-tip elements. An algorithm based on the maximum tensile-stress criterion is then developed and incorporated into the boundary element model to predict the paths of cracks propagating in layered elastic materials.In the experimental part of this study, crack profiles for straight-through-cracked, compact-tension specimens of the anodically bonded silicon/Pyrex glass system are measured by profilometry. The plane strain prediction of the crack-propagation path is compared with the experimentally measured crack profiles. Consistent with the prediction, the interfacial crack is observed to kink away from the strong, anodically-bonded interface and propagate into the more compliant glass layer. The predicted initial kink angle of 26° agrees very well with the average measured value of 28°. The measured path of the crack is also in very good agreement with the predicted path over about the first 120 microns of crack growth with increasing deviation observed beyond that.     

Offshoring manufacturing: Implications for engineering jobs and education: A survey and case study

One result of globalization is the rapid growth of offshoring, i.e., the outsourcing of functions and jobs to offshore locations. In the USA, offshoring has progressed to the point where it already affects everyday lives, from the cars we drive (of which a large portion of the work and components are outsourced) to computers (which are typically manufactured offshore and shipped back to the USA), to electronic diagnostics (where calls are answered overseas). This phenomenon has implications on our lives and on the jobs that engineers and scientists will assume both now and in the future. Further, it is something that all highly developed and even some lesser-developed countries must face. Consequently, the growth of outsourcing will have a major impact on the educational objectives of engineering programs and the resultant engineering curricula worldwide.

This paper presents recent data on product and job offshore migrations and discusses the various dimensions of this phenomenon. In addition to the potential loss of engineering and other high-end technical jobs, sociological and cultural aspects, intellectual property issues, strategic planning concerns, and macro-economic issues are presented. For example, the effects of offshoring on the societal fabric of the countries that are recipients of manufacturing and service center outsourcing, such as China and India, are significant, rapid, and controversial. Offshoring has also begun to change the way that engineering programs in these countries educate their students. In addition, intellectual property issues create a major risk to companies considering outsourcing to certain less-developed countries. These issues can be broadly categorized into: the robustness and strength of intellectual property laws, and the degree to which these laws are implemented and enforced. Further, such factors as currency fluctuations and geo-political conditions can substantially impact outsourcing decisions and profitability.

The phenomenon of offshoring, which is now affecting engineering careers, will play a major role in shaping engineering education worldwide. The next generation of engineers will need to possess the ability to work seamlessly across cultures, have outstanding communication skills and be familiar with the principles of project management, logistics, and systems integration. Some educational models that begin to address these requirements will be presented.     

Learning from traditional built environment of Cyprus: Re-interpretation of the contextual values

Last century witnessed the tragic results of ethnic separations between Turkish and Greek Cypriots, which were the two main communities of Cyprus Island. Both communities; that used to live mixed together on the same geography, shared the same history, culture, lifestyle and moreover the future. Nowadays, the bi-communal efforts on the Island, encouraged by the international society, provide the opportunity to union and heal the traces of the traumatic division. The new century promises a rapid increase in the welfare of Cypriots parallel to the solution of the political dispute. The sudden change in economical structure can increase the threat on the unique traditional environment as a result of unplanned and inevitable developments for fulfilling the rising demands. For the sake of having a contemporary living milieu, the traditional environment as the common architectural heritage of the Island can be revitalized, besides developing new appropriate architectural solutions in the light of the natural and cultural context. The Island's housing tradition bears the opportunity to be learned from the tried and evolved architectural solutions. Evaluating these values parallel to today's discourse, sustainable identity can be achieved by emphasizing especially the locality. In brief, this study tries to define the appropriate design principles for the contemporary housing developments and finds the ways of sustaining existing unique traditional patterns.     

Advanced oxidation of commercial textile biocides in aqueous solution: effects on acute toxicity and biomass inhibition.

In the present study, the decomposition of two biocides used in the textile finishing process with Advanced Oxidation Processes (AOPs) has been studied. Different AOPs, i.e O3/OH-, TiO2/UV-A and Fe2+/H2O2 have been used representing mutually combined components of the chemically and photochemically driven advanced oxidation systems. The course of reaction was examined by changes in chemical oxygen demand (COD), total organic carbon (TOC) and acute toxicity towards the water flea Daphnia magna (assessed in terms of the effective dilution ratio LD50). Particular attention has been paid to determine the inhibitory effect of raw and ozonated biocides on biological activated sludge consortium at concentrations typically encountered in textile finishing effluents. Significant oxidation and mineralization of both biocides could be achieved employing ozonation at pH = 11.5 and heterogeneous photocatalysis (TiO2/UV-A) at pH = 5.0, whereas Fenton's reagent appeared to be less effective in COD and acute toxicity abatement.     

Functionalization of cotton fabric with nanosized TiO<Subscript>2</Subscript> coating for self-cleaning and antibacterial property enhancement

In this study, titanium dioxide (TiO₂) was used as coating compound to add self-cleaning and antibacterial functionality properties to the cotton fabric. TiO₂-consisting coating compounds were prepared at four different processing temperatures (20, 40, 60, and 80°C) in order to examine the influence of process temperature on average particle size. Among the prepared solutions, the one prepared at 80°C process temperature was selected for the dip coating application of the 100% cotton fabric, which formed a transparent nanosized TiO₂ film on the fibrous structure of fabric. Dip coating trials were done at five coating temperatures of 20, 40, 60, 80, and 100°C. TiO₂-coated and uncoated fabric samples were then tested to evaluate their self-cleaning and antibacterial activities. A self-cleaning activity test was conducted using uncoated and TiO₂-coated fabric samples which were stained with hot tea solution via dipping method. Stained fabric samples were illuminated under a solar simulator for the color changes to measure photocatalytic degradation of stain colors. Antibacterial performance of TiO₂-coated and uncoated fabric samples was determined against pure cultures of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213.