Determination of the principal parameter of ultrasonic pulse velocity and compressive strength of lightweight concrete by using variance method

Experiments are usually made to finding maximum ultrasonic pulse velocity and compressive strength of lightweight concrete. In this study, ultrasonic pulse velocity and compressive strength of lightweight concrete made with scoria aggregate, silica fume and fly ash was investigated experimentally and statistically. This article adopts Taguchi approach. The Taguchi method has been used to determine the optimum conditions and to reduce the numbers of experiments. Four control factors (maximum size of aggregate, curing conditions, mineral admixtures and curing time) for this study were used. The level of importance of these parameters on ultrasonic pulse velocity and compressive strength was determined by using analysis of variance (Anova) method. The text was submitted by the authors in English.     

Water recovery from treated urban wastewater by ultrafiltration and reverse osmosis for landscape irrigation

Techno-economic feasibility of water recovery from secondary effluents of an urban wastewater treatment plant (WWTP) for landscape irrigation was investigated considering two distinctive strategies: ultrafiltration (UF)/chlorination and UF/reverse osmosis (RO). Experimental performance evaluations were conducted separately for UF membranes and for different RO trans-membrane pressures. The quality of the effluent recovered by the UF/RO system was in accordance with the national and international guidelines. The produced reuse water was first class quality according to the national guideline for all parameters except sodium adsorption ratio (SAR), which can be eliminated readily by direct addition of KCl into the recovered water. Estimated field-scale costs indicated that UF/RO yielded a total cost of US$12,500,000–13,600,000 with annual operating cost being US$482,000–533,000 at 5–20 bar. The economic estimations guaranteed reimbursement with US$7,600,000–7,400,000 net present value, 0.22–0.39 year payback time, US$0.44–0.49/m³ treatment cost, and a benefit/cost ratio of 0.57.     

Housing price dynamics and bubble risk: the case of Turkey

Abstract

Housing prices have increased substantially in some emerging markets in recent years. Turkish housing market has also experienced a boom over the last decade with rapid house price appreciations. This study is the first to employ two different house price indexes to analyze housing bubble in Turkey in two different time periods, 2010:M1–2014:M12 and 2007:M6–2014:M12. We first capture the determinants of housing price by employing Bounds test and then examine whether rising house prices have been justified by fundamentals by employing OLS/FMOLS/DOLS, Kalman filter and ARIMA models. The Bounds test results suggest that there is a long-term cointegration among house price indexes and housing rent, construction cost and real mortgage interest rate. The results imply that the Turkish housing market has experienced some cases of overvaluation, but not bubble formation. This evidence has several implications for house price dynamics and risks in the Turkish housing market. Based on Turkish experience, the study also draws policy implications for emerging housing markets.     

Modelling of rheological characteristics of various spaghetti types

Spaghetti enriched with resistant starch was produced to increase the dietary fibre intake of consumers. In the product base it was compared to bran and control spaghetti regarding to viscoelastic properties. Viscoelastic properties were tested by relaxation and creep tests by using TA-XT2i texture analyser. The viscoelastic properties gave structural information. Relaxation and creep data were analysed by generalized Maxwell (two- and three-termed), Peleg & Normand, Burgers and Peleg models, respectively. For relaxation three-termed Maxwell and for creep behaviour Burgers model represented viscoelastic behaviour satisfactorily. In general, bran spaghetti was found to have the lowest elasticity. All the samples started to loose their elasticity as cooking time proceeded and it became easy to deform them. Instrumentally, spaghetti with resistant starch was found to be better than bran enriched spaghetti.     

A Survey on Near Field Communication (NFC) Technology

Near Field Communication (NFC) as a promising short range wireless communication technology facilitates mobile phone usage of billions of people throughout the world that offers diverse services ranging from payment and loyalty applications to access keys for offices and houses. Eventually NFC technology integrates all such services into one single mobile phone. NFC technology has emerged lately, and consequently not much academic source is available yet. On the contrary, due to its promising business case options, there will be an increasing amount of work to be studied in the very close future. This paper presents the concept of NFC technology in a holistic approach with different perspectives, including communication essentials with standards, ecosystem and business issues, applications, and security issues. Open research areas and further recommended studies in terms of academic and business point of view are also explored and discussed at the end of each major subject’s subsection. This comprehensive survey will be a valuable guide for researchers and academicians as well as for business world interested in NFC technology.     

Electrical charge transport and optical properties of a poly(methacrylate) with a new side chain and its Ni(II) complex

The electronic conductivity of poly[2‐(2‐hydroxybenzyliden hydrazino)thiazole‐4‐yl methyl methacrylate] bearing a thiazole ring, Schiff base, and hydroxyl group in its side chain and its Ni(II) complex were measured as functions of temperature and frequency. The electrical measurements show the semiconducting nature of the samples as their electrical conductivity increased with increased temperature. Also, the activation energies were below 2 eV, which places them in the semiconductor regime. The conduction mechanism in the samples is discussed. Although extrinsic conduction mechanism occurs in the polymer, intrinsic conduction mechanism take places in its metal complex. The optical absorption spectra were recorded at room temperature and the optical energy gaps of samples were determined by optical spectra. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 741–746, 2003     

Real‐time video postprocessing for deblocking and deringing on mediaprocessors

Blocking and ringing are two major artifacts in highly compressed images and videos coded by block‐based discrete cosine transform. Many existing deblocking and deringing algorithms are computationally very expensive and/or cannot produce satisfactory results at very low bit rates. We have developed an adaptive deblocking algorithm and a clustering‐based deringing algorithm. These algorithms can smooth out the blocking and ringing artifacts while preserving the strong edges and texture areas. In addition, our postprocessing algorithms have low computational cost. We have implemented them on a commercially available, programmable processor. For an image size of 352 × 288, our algorithms take only 3.17 ms, demonstrating the feasibility of real‐time video postprocessing. © 2003 Wiley Periodicals, Inc. Int J Imaging Syst Technol 13, 161–168, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.10052     

Land use change analysis of Beykoz-Istanbul by means of satellite images and GIS.

Management and planning of the natural environment requires spatially accurate and timely information on land use patterns. With repetitive satellite coverage, the rapid evolution of computer technology and the integration of satellite and spatial data, the development of land use applications have become ubiquitous. The integration of Remote Sensing (RS) and Geographic Information Systems (GIS) has been widely applied and recognized as a powerful and effective tool in detecting land use change in urban areas. This paper presents the land use change analysis of the Beykoz region, which is the second largest administrative district of Istanbul. Land use changes and their impacts are monitored using Landsat (MSS - TM) and Spot 5 satellite data in the period of 1975-2001. The independent classification of each satellite image was used as a change analysis method and the resulting images were analyzed with GIS techniques. The results showed that forest area of Beykoz decreased from 80.55% to 70.5% between 1975 and 1984 and during the 1984-2001 periods, the forested area decreased from 70.5% to 68.86% and the urban growth rate was 4.65%.     

Lensfree sensing on a microfluidic chip using plasmonic nanoapertures

We demonstrate lensfree on-chip sensing within a microfluidic channel using plasmonic nanoapertures that are illuminated by a partially coherent quasimonochromatic source. In this approach, lensfree diffraction patterns of metallic nanoapertures located at the bottom of a microfluidic channel are recorded using an optoelectronic sensor-array. These lensfree diffraction patterns can then be rapidly processed, using phase recovery techniques, to back propagate the optical fields to an arbitrary depth, creating digitally focused complex transmission patterns. Cross correlation of these patterns enables lensfree on-chip sensing of the local refractive index surrounding the near-field of the plasmonic nanoapertures. Based on this principle, we experimentally demonstrate lensfree sensing of refractive index changes as small as ～2×10(-3). This on-chip sensing approach could be quite useful for development of label-free microarray technologies by multiplexing thousands of plasmonic structures on the same microfluidic chip, which can significantly increase the throughput of sensing.     

Transparent, highly flexible, all nanowire network germanium photodetectors

We report on the fabrication and characterization of all nanowire (NW) network photodetectors. For this purpose, germanium (Ge) NW networks are used as active semiconducting elements, whereas single walled carbon nanotube (SWNT) and silver (Ag) NW networks are used as the contacts. Following their synthesis, all NW networks are deposited through simple solution based methods. Photoresponse characteristics and transparency of the photodetectors for different Ge NW densities are measured. The fabricated devices show a large response with short relaxation times (<10 ms), are flexible and transparent within the visible spectrum.