Experimental performance evaluations of CoMP and CA in centralized radio access networks

Telecommunication Systems - According to International Mobile Telecommunication’s requirements for 2020, next generation cellular networks such as 5G need to meet certain Key Performance...     

Thermoelastic Enhancement of Damping of Sand Using Synthetic Ground Rubber

This paper examines the possibility of introducing synthetic rubber in constructed earthen systems to improve their vibration attenuation. The results of a series of controlled laboratory tests—aimed to investigate the improvement of low-strain dynamic properties of Ottawa sand by mixing ground rubber of similar size—showed a simultaneous increase in both the shear modulus and the damping ratio of the sand specimens up to an optimum volume proportion of the rubber. Predictions using Hertzian particle contact effects and mechanical damping, resulting from thermoelastic effects between the dissimilar particles, were employed to discern the observed behavior. It is postulated and examined through the available data that the large difference between the elastic modulus of the two materials results in the increase in contact area of the sand and rubber particles and consequently the increase in the stiffness matrix. Similarly, the large difference between the coefficient of thermal expansion of sand and rubber may effectively lead to high thermoelastic enhancement of damping in the sand-rubber mixture.     

Analytical characterisation and production of wool wax from Akkaraman and Morkaraman sheep's wool

The analytical characterisation and production of wool wax from Akkaraman and Morkaraman sheep in the East Anatolien region of Turkey have been investigated. It was shown that the analytical characteristics of Akkaraman and Morkaraman wool waxes differ only slightly from other wool waxes. Therefore, from a quality point of view, wool waxes obtained from this work can be used for the same purposes as wool waxes produced from different varieties of sheep.     

Effects of applied potential on electroinitiated copolymerisation of α-methylstyrene and β-bromostyrene

Electroinitiated cationic copolymerisation of α-methylstyrene and β-bromostryene has been studied at various applied potentials. The relationship between copolymerisation potential and resulting copolymer composition was investigated. The advantages of employing constant potential electrolysis over constant current electrolysis are discussed in terms of the reactivity ratios. The reactivity ratios of the monomers are calculated according to the integrated Lewis-Mayo equation.     

Estimating the groutability of granular soils: a new approach

This paper evaluates different parameters that affect the grouting of soil, and presents a new approach to predict the groutability of granular soil. An accurate prediction of the groutability of granular soils has always been complicated due to the effects of different soil parameters. We know that these parameters are the grain-size of soil and cement-based grouts, the relative density and fine contents of soil, the water/cement ratio of grout mixture and grouting pressure, which directly affect the groutability of soil media. However, the relative density, fine contents of soil, the water/cement ratio, and grouting pressure are seldom considered as the prediction of groutability. In order to study the effects of the parameters on groutability, an alternative empirical formula to estimate the groutability of granular soils is presented in this paper and supported by experimental results obtained from the grouted sand samples prepared with various relative densities. The newly developed approach will help for the more accurate prediction of the groutability in granular soils and may also be used to provide first-hand information about the groutability of soils.     

Predictors of digital piracy among Turkish undergraduate students

Unauthorized downloading or duplication of copyrighted software has been a serious financial and ethical concern. Thus, the current research addressed predictors of digital piracy across two Turkish undergraduate samples. In Study 1, two structural models were tested with 465 students. Latent variables of interest were measured through 21 indicators to address past piracy, present piracy, prosecution risk and piracy attitudes. Followed by the confirmation of the factor structure, two structural models were retained. In the first model, perceived likelihood of prosecution decreased piracy through full mediation of attitudes, whereas past piracy decreased it through partial mediation of attitudes. In the second model, both variables explained current piracy through full mediation of attitudes. In Study 2, 12 social desirability items were added to current measures and tested with a new group (n?=?190). The measurement model was confirmed. While prosecution risk and social desirability was related, their contribution to current piracy behaviors was not significant. The links between past and present piracy and attitudes were still strong.     

A comprehensive review on hydrogen production from coal gasification: Challenges and Opportunities

This paper comparatively discusses hydrogen production options through coal gasification, including plasma methods, and evaluate them for practical applications. In this regard, it focuses on numerous aspects of hydrogen production from coal gasification, including (i) state of the art and comparative evaluation, (ii) environmental and economic dimensions, (iii) energetic and exergetic aspects, (iv) challenges, opportunities and future directions. Furthermore, this review paper outlines what differences it brings in and what contributions it makes to the current literature about such a significant domain of potential hydrogen production which can be used as clean fuel, energy carrier and feedstock. Accordingly, this comprehensive review offers some results as follows: (i) plasma gasification system produces higher amount of hydrogen from other gasification processes, (ii) less amounts of solid wastes (slag, ash, tar, etc.) are released during plasma gasification process compared to other gasification processes, and (iii) it is overall more sustainable Thus, plasma gasification is proposed as a potential option for hydrogen fuel production from coals and for practical application in energy sector. As a case study, some plasma gasifiers in the literature are analyzed in terms of the exergetic sustainability. Furthermore, the case study results show that the exergetic sustainability index decreases from 0.642 to 0.186, and the exergetic efficiency drops from 0.342 to 0.156, while the environmental impact factor increases from 1.556 to 5.372 with an increase of waste exergy ratio from 0.839 to 0.532, respectively.     

The Effect of the Red Mud on Polymer Crystallization and the Interaction between the Polymer-Filler

In this study, the use of industrial waste red mud was investigated as a filler/reinforcement material in composite material production. Polypropylene (PP) was chosen as a matrix material and used with the red-mud with appropriate combinations. A variety of physical and thermal tests were performed on the resultant composites. X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) analysis have been carried out and the relationships between the red-mud content, particle size, and properties were examined. The results showed that the crystal-orientation rate and reduced melting enthalpy increased by increasing red-mud volume but melting temperature was not so affected by the increase of red-mud.     

Levitation Force Density on Different Thicknesses of?YBa2Cu3O7?x Bulk Superconductor Fabricated by?FQMG?Process

A precursor YBCO in the stoichiometric ratio of 1:2:3 was prepared by the flame-quench-melt-growth (FQMG) method. Both the superconducting and nonsuperconducting regions were decided by measuring the magnetic levitation force per unit volume as a function of thickness of the superconducting sample. It was determined that superconducting forming ratio depends on where it forms in the sample, and thus a region near the top surface of the sample contains more superconducting forming ratio than the other regions. The levitation force density measured at different thicknesses of the sample ranging from 6.54 to 1.58 mm firstly increased and then separately reached a saturation point (maximum value) for both repulsive and attractive levitation force density. It was found that the maximum values of the repulsive and attractive levitation forces were respectively 125 mN/cm³ and ?23 mN/cm³. The considerably improved F _L ?z performance in FQMG sample can be translated to large-scale Y123 blocks intended for real superconducting levitation applications.