Performance study of non-orthogonal multiple access (NOMA) with triangular successive interference cancellation

Wireless Networks - The non-orthogonal multiple access (NOMA) allows allocating one carrier to more than one user at the same time in one cell. It is a promising technology to provide high...     

The Turkish handmade carpet industry: an analysis in comparison with select Asian countries

The main purpose of this paper is to analyze the Turkish handmade carpet industry and to compare it with select Far East countries. In particular, the Turkish handmade carpet industry is compared with the handmade carpet industries of Iran, India, China, Afghanistan, Pakistan, and Nepal. In this context, the determinants of handmade carpets in the US market are analyzed empirically. Our results show that the Turkish handmade carpet industry has been experiencing a period of recession in the past decade. Through the relative comparative advantage (RCA) index and the Kreinin–Finger similarity (KFS) index, we observed that the RCA index for Turkey indicates that Turkey’s RCA has been declining since 1992. However, despite this decline, the RCA of Turkey was above that of other countries until 1997. But after this, the advantage disappeared eventually and was gained by Iran. During this period, the other competitors of Turkey showed small increases. Furthermore, the empirical results from the gravity model suggests that a 10% real depreciation/appreciation of the US dollar against foreign currency leads to a 0.2% decrease/increase in imports. This finding suggests relatively low exchange rate import pass‐through in carpet commodity. The results also support the Linder hypothesis that countries with similar preferences and demand structures will tend to trade more.     

Production of Isoamyl Acetate from Sugar Beet Molasses by Williopsis saturnus var. saturnus

Three strains of Williopsis saturnus var. saturnus were employed for the production of natural isoamyl acetate (the character impact compound of banana flavour) using sugar beet molasses as the carbon source and batch cultivation at 25°C under anaerobic conditions. Of the three strains, strain HUT 7087 was the best producer of isoamyl acetate, producing 20.7 mg/L. Sugar beet molasses was deemed to be an acceptable carbon source for the production of this flavour compound.     

Screening of the antioxidative and antimicrobial properties of the essential oils of Pimpinella anisetum and Pimpinella flabellifolia from Turkey

The aerial parts of two endemic Pimpinella [Pimpinella anisetum Boiss. & Ball. and Pimpinella flabellifolia (Boiss.) Benth. ex Drude] were hydro-distilled to produce oils in the yields of 2.07% (v/w) and 2.61% (v/w), respectively. The oils were analysed by GC and GC/MS. Twenty-one and nineteen components were identified, representing 99.5% and 99.7% of the oils, respectively. The main compounds of P. anisetum were (E)-anethole (82.8%) and methyl chavicol (14.5%), whereas limonene (47.0%), (E)-anethole (37.9%) and α-pinene (6.0%) were the major constituents of P. flabellifolia. The oils were screened for their possible antioxidant activities by two complementary test systems, namely DPPH free radical-scavenging and β-carotene/linoleic acid systems. In the first case, P. anisetum oil exerted greater antioxidant activity than that of P. flabellifolia oil with an IC₅₀ value of 5.62 ± 1.34 μg/ml. In the β-carotene/linoleic acid test system, the oil of P. anisetum was superior to P. flabellifolia with 70.5% ± 2.86 inhibition rate. Essential oils of the plants studied here were also screened for their antimicrobial activities against six bacteria and two fungi. The oils showed moderate antimicrobial activity against all microorganisms tested.     

Multi‐Criteria Usability Evaluation of Electronic Devices in a Fuzzy Environment

The user‐oriented design is the most important competition issue in today's market. In recent years, user‐oriented design (i.e., usability) has become expected, particularly in electronic devices. Usability considers high user satisfaction in conjunction with user performance. Usability of electronic products is essential for high customer satisfaction as well as product life cycles in companies. Therefore, MP3 players were selected among the electronic products. Designing usable MP3 players is extremely important for users who have close interaction with them. In this study, MP3 players of different types and sizes were selected and their usability evaluated. The usability criteria used in the MP3 players' evaluation were divided into two major categories: performance and emotional expectations. The alternatives were ranked with fuzzy multi‐criteria decision‐making methods, namely, Fuzzy TOPSIS (FTOPSIS), Fuzzy Analytic Hierarchy Process (FAHP), and Fuzzy Axiomatic Design Theory (FADT), and the results were compared. Although the same decision matrices and data obtained from semantic differential experiment were used for all fuzzy multi‐criteria decision‐making methods, it is shown that different rankings were obtained. © 2012 Wiley Periodicals, Inc.     

Low-temperature creep of a carburized steel

The low-temperature creep behavior of carburized 4320 steel with retained austenite contents of 35 and 14 pct and two uncarburized 4320 steels was investigated. The temperature range in the experiments was from 70 °C to 195 °C. The creep rate obeyed a logarithmic law when the stress level was below or near the proportional limit. A kinetic model is presented which de-scribes the low-temperature creep behavior of this steel under different stress and temperature conditions. The techniques for determining the constants in the model are given. Formerly Visiting Assistant Professor, Department of Mechanical and Industrial Engineering, University of Illinois     

Passive control of circular cylinder wake in shallow flow

The control of vortex shedding of a circular cylinder in shallow water using a splitter plate located in the downstream of the circular cylinder was studied by employing particle image velocimetry (PIV) technique. Experiments were carried out in a water channel having a test section of 8000 mm × 1000 mm × 750 mm dimensions at a Reynolds number of 6250. The length of the splitter plate (L) was varied within the range of 0.5 ? L/D ? 2 with an increment of 0.5. The plate was submerged into water at different height ratios (h_p/h_w) such as 0.25, 0.5, 0.75 and 1.0. Mean velocity vector field, corresponding vorticity contours, streamline topologies and turbulent quantities were calculated using 300 instantaneous velocity vector field measured by PIV. As the ratio of h_p/h_w increases, the effect of the splitter plate on the suppression of the vortex shedding increases. Flow characteristics and examination of spectra indicate that Karman vortex shedding is attenuated pronouncedly for the cases of L/D ? 1 and h_p/h_w ? 0.75. The transverse Reynolds normal stress is more effective on the attenuation of turbulent kinetic energy than the streamwise Reynolds normal stress. The value of peak transverse Reynolds normal stress is reduced to 90% of that of the bare cylinder at most.