A Thermoplastic Polyurethane /Nanosilica Composite via Melt Mixing Process and its Properties

Silicon - This investigation reports the preparation and properties of thermoplastic polyurethane/silica nanocomposite prepared via melt mixing process. In this case, nanosilica at different...     

Modeling the slake durability index using regression analysis, artificial neural networks and adaptive neuro-fuzzy methods

Clay bearing, weathered and other weak rocks cause major problems in engineering practice due to their interactions with water. The slake durability index (I _d2) is an important tool used to assess the resistance of these rocks to erosion and degradation, but sample preparation for this test is tedious. The paper reports an attempt to define I _d2 through statistical models using other parameters that are simpler to obtain. The main objective of this study was to define the best empirical relationship between the I _d2 and the point load strength index (I _s(50)), dry unit weight (γ _d) and fractal dimension (D) parameters of eight rock types by applying general multiple linear regression (GLM), artificial neural networks (ANN) and adaptive neuro-fuzzy inference systems (ANFIS). The models obtained were evaluated using the R ², MSE, MARE and d parameters. The results indicate that the relationships between I _d2 and γ _d, I _s(50) and D were best obtained using ANN, followed by GLM and ANFIS. It is concluded that ANN modelling is a fast and practical method of establishing I _d2.     

Two polymorphs of Ba3Sn2P4: Single crystal and electronic structures

Two polymorphs (I and II) of Ba₃Sn₂P₄ have been found in the same preparative batch. Both compounds crystallize in the centrosymmetric monoclinic space group P2₁/c (#14, a = 7.8669(2) Å, b = 19.2378(5) Å, c = 7.8472(2) Å, β = 112.77(1)°, V = 1095.06(5) Å³, Z = 4, and R/wR = 0.0303/0.0710 for I; a = 7.8771(3) Å, b = 19.4099(7) Å, c = 7.7040(3) Å, β = 112.44(1)°, V = 1088.67(7) Å³, Z = 4, and R/wR = 0.0224/0.0415 for II). Both structures consist of one-dimensional chains separated by Ba²⁺ cations. The isolated chain consists of condensed ethane-like [Sn₂P₆] units. In polymorphs I and II, the condensation and connectivity of the [Sn₂P₆] units are quite different. While [Sn₂P₆] units form four- and six-membered rings in I, they form the five-membered rings in II. The electronic structure calculations indicate that semiconducting behavior is expected for both compounds.     

High-gain W-band-printed antenna on flexible substrate

This article demonstrates a novel type of series-fed planar antenna array for a W-band (70 GHz) application. The proposed architecture is a 5-element antenna array with 10 numbers of gap-coupled parasitic patches in microstrip configuration over a thin, flexible and bio-compatible substrate named LCP (liquid crystal polymer). A detailed design methodology with all fabrication constraints has been elaborated on here. Full wave analysis of the whole structure has been carried out in the FEM-based 3D electromagnetic (EM) solver ANSYS HFSS Suite V.19.2. Parametric simulations were studied to achieve the optimized values of all design parameters. Further, an empirical electrical equivalent circuit model is proposed for the antenna array, and it was validated with the simulation results obtained from the FEM solver. Two prototypes have been fabricated, and measurements were carried out to fetch all the designed antenna parameters. The proto version of the antenna offers peak directive gain of about 19 dBi with better than 22 dB of return loss and 80% radiation efficiency for the frequency range of 67–85 GHz. Experimental and simulated results closely match each other. Small deviations are attributed to practical imperfections incurred by fabrication tolerances, measurement inaccuracies, testing, assembly-related issues and so forth. Finally, the current research work is compared with the recently reported literature.     

KB-SCHED: Knowledge-based scheduler for complex and dynamic systems

Scheduling problems are becoming more and more complex everyday. This makes the current rules and algorithms difficult to comply with the requirements. New machines with the capabilities of processing more than one jobs is being developed. Sometimes one job is divided into parts and processed by more than one machine at the same time. These make the current algorithms insufficient. Artificial intelligence technologies, especially expert systems are proven to deal with such dynamic complex problems in several domains. In this study, an example of such a complex problem is introduced and knowledge-based scheduling for these kind of problems is elaborated with a real life industrial example.     

Editorial: Reliable Communication for Emerging Wireless Networks

Mobile Networks and Applications -     

Performance of a Multi-hop UWB Transmitted Reference System using Decode-and-Forward Relays

In this paper, end-to-end average bit error rate (ABER) of a multi-hop decode-and-forward relay system is evaluated using ultra-wideband transmitted reference (TR) receiver over a multi-path fading channel. Distribution of individual hop signal to noise ratio (SNR) is approximated by a log-normal distribution and corresponding ABER is evaluated by Gauss-Hermite Quadrature rule. These individual hop ABERs are then used to find the end-to-end ABER performance analytically which is faster than the simulation method available in the literatures. Performances of three variants of non-coherent TR receivers: simple transmitted reference, average transmitted reference and differential transmitted reference (DTR) receivers are compared assuming same total transmit power for a fixed end-to-end distance in line-of-sight (LOS) and non line-of-sight (NLOS) channel model. It is observed that the end-to-end ABER performance using DTR receivers is the best and multi-hop relaying is also most effective using these receivers to improve the performance. It is also found that the laws of diminishing returns hold for performance gain in average transmit SNR per bit at a particular ABER in LOS channel i.e. performance improvement in terms of transmit SNR is not equal as the number of hop increases. It decreases with increase in hop number but the reverse trend can be found in NLOS channel.     

Entropy Based Image Segmentation for Energy Efficient LTE System with Cloud

Nowadays LTE network provides high speed data transmission for advanced web based applications and consumes lot of energy. Energy consumption needs to be minimized for a mobile devices running on batteries. In this paper, we have considered a problem of minimizing total energy consumption of a mobile device transmitting an image to cloud through LTE network with a specific bit error rate requirement. Total energy consumption per information bit is calculated by measuring computation energy, circuit energy and radio energy. We have also proposed an algorithm to minimize the total energy consumption while transferring the image. The algorithm makes use of the information entropy of the segments that the image contains. We have also given the complexity of the algorithm in terms of the total number of required operations. As compared to the energy required for transferring the fully uncompressed or fully compressed image, our optimized algorithm can save upto 26 % energy. Energy saving depends on transmission distance and required bit error rate.     

Enhanced photocurrent in PbSe nanorod-quantum dot bulk nano-heterojunction solar cells

Journal of Materials Science: Materials in Electronics - Owing to their remarkable multiple exciton generation (MEG) yield, PbSe nanorods (NRs) have been considered as one of the most promising...