An Adaptable and Scalable Generator of Distributed Massive MIMO Baseband Processing Systems

Journal of Signal Processing Systems - This paper presents an algorithm-adaptable, scalable, and platform-portable generator for massive multiple-input multiple-output (MIMO) baseband processing...     

Dynamic model of online information quality perceptions and impacts: a literature review

This paper reviews the literature related to the concept of information quality (IQ) in the context of the online environment to understand how it has been conceptualised in the Information Systems (IS) literature, to identify gaps in the literature, and to make recommendations for future research. This study also extends the Information Processing Model (IPM) and proposes a novel dynamic model of online IQ perceptions and impacts. To understand the online IQ construct, an in-depth review of the literature is conducted. Overall, we reviewed 508 journal articles published between 1995 and 2016. This study found that there is a substantial gap in the IS literature in regards to a full understanding of the online IQ construct and its relation with the IPM. More research is needed to understand the way individuals process and respond to online information. Further, although the importance of context in theory development has been emphasised in the literature, very few empirical articles have explored the impact of contextual factors on the IPM as well as perceived online IQ. The findings provide online vendors with important guidelines that should be considered to motivate individuals to acquire more information from their websites that could lead to more satisfied and loyal users.     

Comparing photocatalytic activity consisting of Sb2S3 and Ag2S on the TiO2–SiO2/TiO2 nanotube arrays-support for improved visible-light-induced photocatalytic degradation of a binary mixture of basic blue 41 and basic red 46 dyes

In the present study, a TiO₂ nanotube (TNAs) supported Sb₂S₃–TiO₂–SiO₂ (STS/TNAs), and Ag₂S–TiO₂–SiO₂ (ATS/TNAs) hybrid novel photocatalysts were prepared and characterized by XRD, FT-IR, SEM-EDX, X-ray mapping and, DRS. EIS was employed, and an equivalent circuit model is proposed. Flat-band potential and free carrier concentration were determined by Mott–Schottky plots. The obtained catalysts were used in the photodegradation of a binary mixture of Basic Blue 41 (BB41) and Basic Red 46 (BR46) dyes. Compared with ATS/TNAs, STS/TNAs photocatalyst showed the highest apparent rate constant for BB41 dye, about two times higher, and BR41 dye more than 1.5 times. EIS results agreed with the photodegradation results, so the STS/TNAs system with higher charge transfer ability than the ATS/TNAs system showed the best photodegradation activity. The optimization effect of the amount of Sb₂S₃, TiO₂, and SiO₂ doped on the TNAs on the photocatalytic activity of the STS/TNAs was done using a central composite rotatable design (CCRD) based response surface methodology (RSM). Results have shown catalyst containing 12.2% Sb₂S₃ and 27.1% SiO₂/TNAs (S₃TS₃/TNAs) the best photodegradation activity was obtained. The GC-Mass analysis was done to detect the degradation intermediates formed during the photodegradation process.     

Performance enhancement of a direct absorption solar collector using copper oxide porous foam and nanofluid

The current research proposes the idea of using water-saturated metal oxide foams and water-based nanofluids as solar absorber in the direct absorption solar collectors (DASCs). Specifically, the novel solar collector design utilizes copper oxide (CuO) porous foam and nanoparticle with high optical properties and is expected to have enhanced thermal performance than the conventional collectors utilizing pure water. The finite volume technique is used to solve the governing equations of flow and heat transfer in the radiative participating media. Also, to establish the reliability and accuracy of numerical solutions, the obtained results are compared with the corresponding numerical and experimental data. The computations are carried out for different nanoparticle volume fractions, foam pore sizes, working fluid mass flow rates, and both porous layer thicknesses and positions (inserted at the lower or upper wall of the collector). It is found that the efficiency of DASC partially/fully filled with metal oxide foam is maximized when the collector is completely filled with it. Compared with the water flow, the numerical results show that the collector efficiency using CuO nanofluid and metal oxide foam is improved by up to 26.8% and 23.8%, respectively. Moreover, considering the second law of thermodynamics, the use of CuO nanofluids in the DASC seems to be more effective than the use of CuO porous foam.     

Effect of Porosity on free and forced vibration characteristics of the GPL reinforcement composite nanostructures

This article investigates the influence of porosity on free and forced vibration characteristics of a nanoshell reinforced by graphene platelets (GPL). The material properties of piece-wise graphene-reinforced composites (GPLRCs) are assumed to be graded in the thickness direction of a cylindrical nanoshell and estimated using a nanomechanical model. In addition, because of imperfection of the current structure, three kinds of porosity distributions are considered. The nanostructure is modeled using modified strain gradient theory (MSGT) which is a size-dependent theory with three length scale parameters. The novelty of the current study is to consider the effects of porosity, GPLRC and MSGT on dynamic and static behaviors of the nanostructure. Considering three length scale parameters ( $l_0=5h$, $l_1=3h$, $l_2=5h$ ) in MSGT leads to a better agreement with MD simulation in comparison by other theories. Finally, effects of different factors on static and dynamic behaviors of the porous nanostructure are examined in detail.     

Platinum‐promoted fibrous silica Y zeolite with enhanced mass transfer as a highly selective catalyst for n‐dodecane hydroisomerization

A fibrous silica zeolite Y (HY@KCC‐1) catalyst with a high surface area of 568 m²/g and unique core‐shell morphology was successfully synthesized via a modified KCC‐1 synthesis method. Characterization of the catalysts was achieved with X‐ray powder diffraction (XRD), field emission scanning microscope (FESEM), N₂ adsorption/desorption, and 2,6‐dimethylpyridine adsorbed Fourier‐transform infrared spectroscopy (FTIR). The Pt/HY@KCC‐1 has displayed complete n‐dodecane conversion coupled with an incredibly enhanced isomer yield of 72% at 350°C, nearly two‐fold higher than that of unmodified Pt/HY catalyst. Remarkably, Pt/HY@KCC‐1 had an internal effectiveness factor (η) of unity and negligible internal diffusion limitation, thus suggesting its potential application in hydroisomerization of higher hydrocarbons for enhancing fuel properties.     

Experimental measurement and correlation of solubility of β-carotene in pure and ethanol-modified subcritical water

For the first time, the solubility of β-carotene in pure and ethanol-modified subcritical water (SW) using the static method was determined. The experimental runs were performed at a temperature ranging from 298.15 to 403.15 K and 0–10% (w/w) of ethanol as a modifier at a constant pressure of 5 MPa. Samples were analyzed by UV–vis spectrophotometer. The solubility of β-carotene was found to range from 1.084 × 10⁻⁸ to 227.1 × 10⁻⁸ mol fractions in the subcritical water in above mentioned conditions. The obtained β-carotene solubility data were correlated using the linear model and modified Apelblat model. The obtained results showed the modified Apelblat model was better for estimating the solubility of β-carotene in SW. The values of the root-mean-square deviation (RMSD) between experimental and correlated data were calculated and used as the index of validity and accuracy for the model. Also, thermodynamic properties of the solution such as the Gibbs free energy of solution, enthalpy, and entropy of solution were estimated.     

A new hybrid chaotic atom search optimization based on tree-seed algorithm and Levy flight for solving optimization problems

Engineering with Computers - Optimizing the high computational real-world problems is a challenging task that has taken a great deal of efforts in the last decade. The meta-heuristic algorithms...