Maximization of total surface area of Pt-SnO<Subscript>2</Subscript>/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> catalyst by the Taguchi method

The maximization of the total surface area of Pt-SnO₂/Al₂O₃ catalyst was studied by using the Taguchi method of experimental design. The catalysts were prepared by sol-gel method. The effects of HNO₃, H₂O and aluminum nitrate concentrations and the stirring rate on the total surface area were studied at three levels of each. L₉ orthogonal array leading nine experiments was used in the experimental design. The parameter levels that give maximum total surface area were determined and experimentally verified. In the range of conditions studied it was found that, medium levels of HNO₃ and H₂O concentration and lower levels of aluminum nitrate concentration and stirring rate maximize the total surface area.     

Films formed from polystyrene latex/clay composites: A fluorescence study

This study reports a steady-state fluorescence (SSF) technique for studying film formation from surfactant-free polystyrene (PS) latex and Na-montmorillonite (SNaM) composites. The composite films were prepared from pyrene (P)-labeled PS particles and SNaM clay at room temperature and annealed at elevated temperatures in 10-min intervals above glass transition temperature (t₃) of polystyrene. During the annealing processes, the transparency of the film improved considerably. Scattered light (I_s) and fluorescence intensity (I_p) from P were measured after each annealing step to monitor the stages of film formation. Evolution of transparency of composite films was monitored by using photon transmission intensity, I_tr. Scanning electron microscopy (SEM) was used to detect the variation in physical structure of annealed composite films. Minimum film formation temperature, T_q, and healing temperatures, T_h, were determined. Void closure and interdiffusion stages were modeled and related activation energies were determined. It was observed that both activation energies increased as the percent of SNaM was increased in composite films.     

Studying high impact fix-inducing changes

As software systems continue to play an important role in our daily lives, their quality is of paramount importance. Therefore, a plethora of prior research has focused on predicting components of software that are defect-prone. One aspect of this research focuses on predicting software changes that are fix-inducing. Although the prior research on fix-inducing changes has many advantages in terms of highly accurate results, it has one main drawback: It gives the same level of impact to all fix-inducing changes. We argue that treating all fix-inducing changes the same is not ideal, since a small typo in a change is easier to address by a developer than a thread synchronization issue. Therefore, in this paper, we study high impact fix-inducing changes (HIFCs). Since the impact of a change can be measured in different ways, we first propose a measure of impact of the fix-inducing changes, which takes into account the implementation work that needs to be done by developers in later (fixing) changes. Our measure of impact for a fix-inducing change uses the amount of churn, the number of files and the number of subsystems modified by developers during an associated fix of the fix-inducing change. We perform our study using six large open source projects to build specialized models that identify HIFCs, determine the best indicators of HIFCs and examine the benefits of prioritizing HIFCs. Using change factors, we are able to predict 56 % to 77 % of HIFCs with an average false alarm (misclassification) rate of 16 %. We find that the lines of code added, the number of developers who worked on a change, and the number of prior modifications on the files modified during a change are the best indicators of HIFCs. Lastly, we observe that a specialized model for HIFCs can provide inspection effort savings of 4 % over the state-of-the-art models. We believe our results would help practitioners prioritize their efforts towards the most impactful fix-inducing changes and save inspection effort.     

Design,development and modelling of single actuated,compliant and symmetrical multi link hopping mechanism

Journal of Mechanical Science and Technology - In this study, we present the design and development of a compliant multi-link hopping mechanism actuated by a single DC motor. Mechanism consists of...     

Using of Photoluminescent Tile for Evacuation of the Buildings During Electrical Failure

Photoluminescent pigments could be successfully applied on the wall tiles, floor tiles and porcelain tiles as well as glass substrates （glass mosaics, borders, and cutted glass with various designs）. For this applications, these products can be used for different purposes. In this study, these pigments are applied on the ceramic tiles and glass mosaics/tiles with traditional ceramic production line. These products are intentended to provide guidance in the event of a power failure. With this study also aimed to prevent potential accidents and injury during evacuation of building.     

Understanding traditional residential architecture in Anatolia

Traditional architecture and associated environments created by residential buildings provide an important focus of interest in contemporary Turkey.1 1. The main thesis of this article is based upon my paper ‘Traditional Residential Architecture in Anatolia’, presented to a seminar on Conservation and Rehabilitation of Half-Timber Structures, Ankara: METU, 1989 and the doctoral thesis submitted to METU, Faculty of Architecture, Program of Restoration in 1994. The concepts have, however, been revised according to more recent surveys. They are generally accepted as physical witnesses of the past to be preserved and studied. Continuity in the traditional characteristics of the social group living in these environments has been observed in many of the extant settlements in Turkey. The reciprocal relationship between the dwelling and its owners, or users, has led to a dual definition of the ‘traditional dwelling unit’: the social unit being the ‘family’, the architectural unit the ‘dwelling’. The existing, modest-scaled, traditional dwellings in Turkey, which constitute the subject of this study, were mostly constructed after the seventeenth century, but more recent buildings exhibiting similar characteristics are also covered by the term ‘traditional’.2 2. The concepts of ‘tradition’, ‘culture’, ‘vernacular’, ‘historical’, ‘regional’, ‘pre-industrial’, ‘popular’ and ‘folk’ fall outside the limits of this study. The term ‘traditional’ has been used throughout the text; the term ‘Ottoman’ has not been adopted due to its attribution to the 1923 constitution of the Turkish Republic — it cannot, consequently, be used as reference to the continuation of tradition, which is one of the main ‘givens’ of this study. A term referring to a geographical distribution of archetype under investigation has been sought. There is an important building stock incorporating similar architectural characteristics within contemporary political boundaries of other countries, such as Iran, Bulgaria, Greece, etc., which had once formed part of the Ottoman Empire. ‘Turkey’ has not been preferred for its reference to the political boundaries of the Republican era for the same reason. Instead, another geographical term ‘Anatolia’ is considered in a widened context throughout the text to refer to a more generic concept than it implies geographically. Anatolia is considered to be the land of origin on which many cultures have emerged, generated and spread to the affected lands throughout history. Furthermore, the concentration of this study focuses specifically on extant dwellings in Anatolia. Within the confines of the term ‘traditional residential architecture in Anatolia’, there are further limitations. The origin of traditional residential architecture in Anatolia, its typological evolution, its social, cultural and/or historical aspects are not the major concerns of this study, which focuses on existing examples. A limitation of the period covered by this study accords with the construction dates of extant buildings from the seventeenth century onwards. This is an open-ended period because of the continuity in ‘traditional’ aspects in many of the settlements. The concept of ‘privacy’ serves as the basis of evaluation in analysing the interrelation of any two units. The interface of two units can be defined as an hierarchy of privacy represented sociologically by the interrelations of person/family/neighbourhood relationships and architecturally through the interrelations of room/dwelling unit/street/neighbourhood.3 3. This dwelling unit was the subject of the studio course ARCH 405 in 1989—1990, Autumn semester. The project was supervised by the author and Res.Asst. Ertu?rul Morçöl; the students were Önder Kaya, Ufuk Serin, Murat Aya?, Deniz Kutay and Gül Vanl?. This approach will include a brief summary of some previous studies of traditional residential architecture (Fig. 1).     

Poly(ε‐caprolactone) composites containing gentamicin‐loaded β‐tricalcium phosphate/gelatin microspheres as bone tissue supports

In this work, novel antibacterial composites were prepared by using poly(ε‐caprolactone) (PCL) as the main matrix material, and gentamicin‐loaded microspheres composed of β‐tricalcium phosphate (β‐TCP) and gelatin. The purpose is to use this biodegradable material as a support for bone tissue. This composite system is expected to enhance bone regeneration by the presence of β‐TCP and prevent a possible infection that might occur around the defected bone region by the release of gentamicin. The effects of the ratio of the β‐TCP/gelatin microspheres on the morphological, mechanical, and degradation properties of composite films as well as in vitro antibiotic release and antibacterial activities against Escherichia coli and Staphylococcus aureus were investigated. The results showed that the composites of PCL and β‐TCP/gelatin microspheres had antibacterial activities for both bacteria. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Dual Polymer Conditioning of Water Treatment Residuals

Conditioning of either wastewater biosolids or water treatment residuals conventionally utilizes a single polymer to improve subsequent dewatering. The sequential addition of two polymers has been reported to enhance biosolids dewaterability, but comparable benefits have not been demonstrated for water treatment residuals. This paper evaluated the use of cationic and nonionic polymers, singly and in combination (dual), to investigate whether dual polymer conditioning of residuals offers any advantages, and to determine whether the results could be accommodated by current mechanistic understandings. For this purpose, lab-scale tests used capillary suction time (CST), supernatant viscosity, zeta potential, streaming current, turbidity, floc size, and rheometric analyses. Comparisons of CST and viscosity results for single and dual polymer additions indicated that dual polymer use gave moderately improved dewaterability, possibly due to the increased mixing utilized for dual polymer addition. Using a cationic polymer produced a less turbid supernatant. Zeta potential and streaming current were not good indicators of conditioning efficacy when a nonionic polymer was used. Rheometric analyses were only meaningful in one selected method for treatment of the data: the area under the rheogram up to a shear rate of 30?inverse?s. Overall, implementation of dual polymer use does not appear warranted.