Leaching kinetics of colemanite by aqueous EDTA solutions

The dissolution kinetics of colemanite, a boron-containing mineral, in aqueous disodium EDTA solutions were studied. The effects of concentration and pH of the solution, particle size, and temperature were examined. A decrease in pH and particle size increased the dissolution rate, while an increase in the concentration of the solution and temperature increased the rate. The activation energy and pre-exponential factor were calculated as 50.6 kJ mol^-1 and 5.14 x 10⁷ m s^-1, respectively. Mahir Alkan, Assistant Professor, formerly with Atatürk University, Kazim Karabekir Faculty of Education     

Minimum energy transmission scheduling subject to deadline constraints

We consider the problem of transmission scheduling of data over a wireless fading channel with hard deadline constraints. Our system consists of N users, each with a fixed amount of data that must be served by a common deadline. Given that, for each user, the channel fade state determines the throughput per unit of energy expended, our objective is to minimize the overall expected energy consumption while satisfying the deadline constraint. We consider both a linear and a strictly convex rate-power curve and obtain optimal solutions, based on dynamic programming (DP), and tractable approximate heuristics in both cases. For the special non-fading channel case with convex rate-power curve, an optimal solution is obtained based on the Shortest Path formulation. In the case of a linear rate-power curve, our DP solution has a nice “threshold” form; while for the convex rate-power curve we are able to obtain a heuristic algorithm with comparable performance with that of the optimal scheduling scheme. Alessandro Tarello received his M.Sc. and Ph.D. degrees in Electrical and Communication Engineering from Politecnico di Torino, Torino, Italy, in 2002 and 2006 respectively. He currently holds a Postdoctoral position at Politecnico di Torino. He visited the Laboratory for Information and Decision Systems at MIT, Cambridge, MA, USA, in 2004 and 2005. During Summer 2005 he also visited the Jet Propulsion Laboratory, Pasadena, CA, USA. He received the best student paper award at the Third International Symposium on Modeling and Optimization in Mobile, Ad-Hoc and Wireless Networks (WiOPT’05). His research interests are in the fields of stochastic and fluid models for performance evaluation of packet networks and optimization techniques for wireless and ad-hoc networks. Jun Sun received his B.S. degree in Computer Engineering from University of Florida in 1997 and his M.S. in Electrical Engineering from Massachusetts Institute of Technology in 2002. He is currently a Ph.D. student in the Laboratory for Information and Decision Systems at MIT. His research interest is on communication networks with emphasis on satellite and wireless networks. Murtaza Zafer received his B.Tech degree in Electrical Engineering from the Indian Institute of Technology (IIT), Madras, India, in 2001 and his M.S. degree in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology (MIT), MA, USA, in 2003. Currently, he is pursuing his doctoral studies at the Laboratory for Information and Decision Systems (LIDS) in the department of Electrical Engineering and Computer Science at MIT. He spent the summer of 2004 at the Mathematical Sciences Research center, Bell Laboratories and the summer of 2003 at Qualcomm, Inc. His research interests lie in queueing theory, information theory, control and optimization theory and its applications to wireless communication networks. He is the co-recipient of the best Student Paper award at WiOpt, 2005. He also received the Siemens (India) and Philips (India) award for academic excellence. Eytan Modiano received his B.S. degree in Electrical Engineering and Computer Science from the University of Connecticut at Storrs in 1986 and his M.S. and PhD degrees, both in Electrical Engineering, from the University of Maryland, College Park, MD, in 1989 and 1992 respectively. He was a Naval Research Laboratory Fellow between 1987 and 1992 and a National Research Council Post Doctoral Fellow during 1992–1993. Between 1993 and 1999 he was with MIT Lincoln Laboratory where he was the project leader for MIT Lincoln Laboratory’s Next Generation Internet (NGI) project. Since 1999 he has been on the faculty at MIT; where he is presently an Associate Professor. His research is on communication networks and protocols with emphasis on satellite, wireless, and optical networks. He is currently an Associate Editor for Communication Networks for IEEE Transactions on Information Theory and for The International Journal of Satellite Communications. He had served as a guest editor for IEEE JSAC special issue on WDM network architectures; the Computer Networks Journal special issue on Broadband Internet Access; the Journal of Communications and Networks special issue on Wireless Ad-Hoc Networks; and for IEEE Journal of Lightwave Technology special issue on Optical Networks. He is the Technical Program co-chair for Wiopt 2006, IEEE Infocom 2007, and ACM MobiHoc 2007.     

Effect of interpolation on specular reflections in texture‐based automatic colonic polyp detection

Reflections of LED light cause unwanted noise effects called specular reflection (SR) on colonoscopic images. The aim of this study was to seek answers to the following two questions. (a) How are the texture features used in automatic detection of polyps affected by the interpolation on specular reflections? (b) If they are affected does it really affect the classification performance? In order to answer these questions, we used 610 colonoscopy images, and divided each image into tiles whose sizes were 32‐by‐32 pixels. From these tiles, we selected the ones without any specular reflection. We added different shape and size specular reflections cropped from real images onto the reflection‐free tiles. We then used the nearest neighbors, bilinear and bicubic interpolation techniques on the tiles on which SRs were added. On these tiles we extracted 116 texture features using 3 second‐order approaches, and 4 first‐order statistics. First, we used paired sample t test. Second, we performed automatic classification of polyps and background using random forest and k nearest neighbors (k‐NN) approaches using the texture features for different combinations of specular reflections added on the tiles from the polyp or background. The results showed that depending on the size of specular reflection, interpolation can cause a significant difference between the texture features that were coming from reflection‐free tiles and the same tiles on which interpolation was performed. In addition, we note that bicubic interpolation may be preferred to eliminate specular reflection when texture features are used for background and polyp discrimination.     

Questioning the “prototype dwellings” in the framework of Cyprus traditional architecture

As one of the basic narratives of culture, traditional residential architecture is an important value, indicating its relationship with its environment. Due to this, the continuity of culture in rural areas is closely related with the sustainability of traditional residential architecture. Cyprus is a Mediterranean island, which has managed to sustain her rich cultural heritage against the many economical, socio-cultural and political changes she has gone through. There is a need for new dwellings in rural areas and this demand is increasing rapidly. In these areas which are physical environments where sustainability can be maintained easily, the Social Housing Department of the North Cyprus Government has made several studies for the proposal of prototype house plans’ as a solution to the above mentioned problem of a need for housing and the prevention of migration to cities. However, upon analysing the architecture of traditional dwellings; and the life-styles of the people who live in these rural areas, it has been observed that these projects, with incomprehensible, strict and totalitarian design principles, are incompatible with local culture and conditions. It is suggested that there is a need for an appropriate environment for the continuation of the life-style that is natural to the people that live within them. On the contrary, these projects form the basis of a step towards a monotonous settlement development which does not respect either the values of traditional architecture or local identities. It is extremely important that the correct steps are taken for both the conservation of the existing physical environment and for handling the issues of new settlement developments in relation to production relationships and cultural sustainability. The main aim of this paper is to draw attention to the traditional design principles that can be re-interpreted in the proposed ‘prototyped dwellings’ in North Cyprus. In order to achieve this aim, a case study, based on observations, literature survey and site survey techniques has been carried out.     

A Novel Approach to Limit Chemical Deterioration of Gilthead Sea Bream (Sparus aurata) Fillets: Coating with Electrospun Nanofibers as Characterized by Molecular,Thermal, and Microstructural Properties

Coating of sea bream fillets with thymol loaded chitosan based electrospun nanofibers (TLCN) and chitosan based nanafibers (CN) has been presented a novel approach to delay chemical deterioration. We assessed CN and TLCN with respect of scanting of total volatile basic nitrogen (TVBN), trimethylamine (TMA), thiobarbituric acid (TBA) deterioration during cold storage condition. Electrospinning process was applied to obtain TLCN and CN. Both of nanofibers obtained from biopolymer and bioactive material were cylindrical, smooth, beadless. Thermal, molecular, zeta potential (ZP), and surface properties of the groups were investigated, revealing that CN indicated molecular interactions with thymol in nanofibers, reduce in physical properties of these structures, thermal decomposition (an alteration in mass of CN and TLCN at temperatures below 190 °C, corresponding to 20.53% and 19.97%, respectively) and also dispersion stabilities (ζ potential) of CN and TLCN were determined 33.68 ± 3.35 and 21.85 ± 1.96 mV, respectively. TVBN and TMA stability analyses demonstrated that CN and TLCN were both effective in delaying chemical deterioration of fish fillets, furthermore TLCN was more effective against chemical deterioration. TBA analyses results of fish fillets indicated that CN and TLCN delayed rancidity in fish meat as compared to control group samples. The presented study results suggested that coating of the sea bream fillets with CN and TLCN would be a promising approach to delay the chemical deterioration of fish fillets.