NOMA using intelligent reflecting surfaces with adaptive transmit power and multi-antennas energy harvesting

Wireless Networks - In this paper, we propose the use of Intelligent Reflecting Surfaces (IRS) between the secondary source and K secondary users. The secondary source transmits the combination of...     

Cellulose/PEO blends with enhanced water absorption and retention functionality

This study introduces a novel biodegradable material produced from processing cellulose and regenerating it in aqueous high-molecular-weight polyethylene oxide (PEO). X-ray diffraction and transmission electron microscopic analysis show that the blend is highly amorphous and contains a networked structure of cellulose with packets of PEO encapsulated within the network. Thermal analysis shows that the water loss from the blend is much slower than that from cotton at temperatures above the boiling point of water, which proves enhanced water absorption and retention properties of the material. It is found that when the material is mixed with sand, up to 1% by weight, the amount of time of water retention in sand increases more than three times. Because of this characteristic, it could be used to improve water storage and availability in sandy soils and to reduce irrigation costs in arid climates. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermoelectrically controlled micronozzle — A novel application for thermoelements

This paper introduces and assesses the concept of the recently invented thermoelectrically controlled micronozzle (TECMN). A generalized quasi-one-dimensional model for gas flow, which is influenced by area variation and by wall heat transfer, is considered. In order to assess the merits of wall temperature control in micronozzles, the flow in the micronozzle is solved numerically for cases of convergent wall heating, divergent wall cooling, and a combination of both. Thermal efficiency and specific impulse are affected by heat exchange through the side wall of the micronozzle. By cooling the divergent section, kinetic energy increases, thus improving thermal efficiency. The mass flow rate is decreased in all cases that include convergent section heating, thereby enhancing specific impulse. The combination of convergent section heating with divergent part cooling results in significant performance enhancement in terms of thermal efficiency and specific impulse. To determine the TECMN wall temperature profile, we developed a one-dimensional general energy model for a thermoelement (TE) subject to an electric field as well as for heat convection on the lateral surface. The energy equation is analytically solved for constant properties and for Joule heating equivalent to heat convection. The temperature profile is then imposed on the quasi-one-dimensional flow model, which is solved numerically for various mass flow rates and exit wall temperature (cold junction). As the exit section wall temperature and mass flow rate decrease, the utilization of TEs to control the temperature of micronozzle walls considerably increases the Mach number at exit.     

Nanocrystalline cellulose reinforced PVDF-HFP membranes for membrane distillation application

Polyvinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) membranes containing different amounts of nanocrystalline cellulose (NCC) were fabricated by electrospining technique for application in membrane distillation (MD). The effect of incorporating NCC on the mechanical strength, morphology, pore size distribution, and liquid entry pressure (water) of the fibrous was investigated. Incorporation of NCC in PVDF-HFP matrix improved the tensile strength and Young's modulus and narrowed down the pore size distribution of the fabricated membranes. Liquid entry pressure, which is an important parameter to ensure high salt rejection of the membranes in MD, was improved from ~ 19 psi to ~ 27 psi with the addition of 2 wt.% NCC. Fabricated membranes were tested in direct contact membrane distillation (DCMD). MD operation data revealed water flux of 10.2–11.5 Lh^− 1 m^− 2 with salt rejection of 99% for these NCC-incorporated membranes.     

Effect of processing conditions on dimensions of sisal fibers in thermoplastic biodegradable composites

Biodegradable composites based on treated and untreated sisal fiber and mater Bi‐Z were processed using an internal batch mixer. The effect of processing conditions (temperature, speed of rotation, and time of mixing) and alkaline treatment on the dimensions of sisal fiber was studied. The length and diameter of the initial fibers were reduced during mixing and this effect was correlated to the magnitude of the shear stress developed in the mixer. An increase of the speed of rotation and/or a reduction of temperature produced fibers of smaller dimensions but with a higher aspect ratio l/d. Alkaline treatment increased the kinetics associated to the reduction of the fiber's dimensions. A semiempirical model was employed to predict the size of the fibers versus the time of mixing. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1084–1091, 2001     

Urolithin A and B Alter Cellular Metabolism and Induce Metabolites Associated with Apoptosis in Leukemic Cells

Leukemia is persistently a significant cause of illness and mortality worldwide. Urolithins, metabolites of ellagic acid and ellagitannins produced by gut microbiota, showed better bioactive compounds liable for the health benefits exerted by ellagic acid and ellagitannins containing pomegranate and walnuts. Here, we assessed the potential antileukemic activities of both urolithin A and urolithin B. Results showed that both urolithin A and B significantly inhibited the proliferation of leukemic cell lines Jurkat and K562, among which urolithin A showed the more prominent antiproliferative capability. Further, urolithin treatment alters leukemic cell metabolism, as evidenced by increased metabolic rate and notable changes in glutamine metabolism, one-carbon metabolism, and lipid metabolism. Next, we evidenced that both urolithins equally promoted apoptosis in leukemic cell lines. Based on these observations, we concluded that both urolithin A and B alter leukemic cell metabolome, resulting in a halt of proliferation, followed by apoptosis. The data can be used for designing new combinational therapies to eradicate leukemic cells.     

Synthesis and morphology analysis of electrospun copper nanowires

We report the fabrication of copper nanowires (NWs) using electrospinning technique. This processing technique was used successfully to synthesize copper NWs with various morphologies using a precursor composed of copper acetate salt and poly(vinyl) alcohol. The obtained NWs were characterized through high resolution scanning electron microscopy and atomic force microscopy and it was found that their morphology is sensitive to the applied voltage and solution flow rate. Their diameter decreased with increasing voltage and increasing flow rate. Moreover, at higher flow rate and lower voltage, the roughness of NWs became more pronounced. In addition, further improvement in NW morphology may be obtained with appropriate heat treatment. These copper NWs with varying morphologies and microstructures have potential applications in different engineering domains such as electronics, optoelectronics, and catalysis.     

A numerical model for real-time simulation of ship-ice interaction

A ship advancing in level ice will introduce several failure processes to the ice sheet, such as localised crushing and breaking due to bending stresses. The resulting ice fragments will interact with each other, with water and with the hull of the ship. They may rotate, collide, or slide along ship's hull, and eventually they will be cleared away. The situation is different in a broken ice field, i.e., large ice floes may behave similar to level ice while smaller floes will mostly be pushed aside, rotated or submerged. Modelling of such a complex system is very demanding and often computationally expensive which would typically hinder the chances for real-time simulations. This kind of simulations can be very useful for training personnel for Arctic offshore operations and procedures, for analysing the efficiency of various ice management concepts and as a part of the onboard support systems for station keeping. The challenge of meeting the real-time criterion is overcome in the present paper. The paper describes a numerical model to simulate the process of ship-ice interaction in real-time. New analytical closed form solutions are established and used to represent the ice breaking process. PhysX is used for the first time to solve the equations of rigid body motions in 6 degrees of freedom for all ice floes in the calculation domain. The results of the simulator are validated against experimental data from model-scale and full-scale tests. The validation tests exhibited a satisfactory agreement between the model calculations and experimental measurements.     

A Review of Indoor Localization Techniques and Wireless Technologies

Wireless Personal Communications - This paper introduces a review article on indoor localization techniques and technologies. The paper starts with current localization systems and...