Improving cell edge throughput for LTE using combined uplink power control

Uplink power control is used in 3GPP Long Term Evolution (LTE) systems to maximize the power of the desired received signals while limiting the interference. This paper analyzes two power control mechanisms, Fractional Power Control (FPC) and Interference Based Power Control (IBPC). A way of combining them is proposed in order to find an efficient algorithm to control the transmitted Power Spectral Density (PSD) in order to compensate poor channel conditions and thus to obtain better performance in terms of cell edge throughput.     

Stimulation of negative magnetoresistance by an electric field and light in silicon doped with boron and manganese

It is experimentally ascertained that light stimulates the negative magnetoresistance observed in a high electric field in silicon doped with boron and manganese. The optimum conditions (the electric field, temperature, illumination, and resistivity of the material) for observation of the largest magnitude of negative magnetoresistance in (Si:B):Mn are determined. The dependence of the negative magnetoresistance on the concentration of compensating impurity is established.     

Influence of mass transport on the performance of carbon gas-diffusion air electrodes in alkaline solution

The effect of mass transport on the electrochemical behaviour of carbon gas-diffusion air electrodes in alkaline solution was investigated on the basis of ΔE(i) curves. These curves are obtained by subtraction of potential values for an electrode operating with airE _air(i) from potential values for the same electrode operating with pure oxygenE _oxygen(i) at the same current densityi. Three different regions on these curves connected with different modes of mass transport are recognized. A model of the gas-diffusion air electrode which takes into account the diffusion of the gas, diffusion of the dissolved gas, electrochemical reaction and IR drop is used to explain the experimental results.     

Antibacterial and antifungal activities of selected microalgae and cyanobacteria

In vitro activity of nine cyanobacterial and ten microalgal newly isolated or culture collection strains against eight significant food‐borne pathogens has been evaluated and compared. Water extracts and culture liquids of Gloeocapsa sp. and Synechocystis sp. demonstrated the widest spectrum of activity with minimal inhibitory concentration (MIC) ranging from 1.56 to 12.5 mg mL^?1. Culture liquid of Anabaena sp. had the highest activity (MIC = 0.39 mg mL^?1) but only to Gram‐positive bacteria. Ethanol extracts and fatty acids from all cyanobacteria and microalgae were active against Streptococcus pyogenes and/or Staphylococcus aureus. The fatty acids of Synechocystis sp. inhibited the growth of Bacillus cereus, Escherichia coli and Candida albicans (MIC values of 2.5–1.25 mg mL^?1, respectively). Exopolysaccharides (EPS) of Gloeocapsa sp. were the sample that exhibited activity against all test pathogens with lowest MIC values (0.125–1 mg mL^?1). High activity with a narrower range of susceptible targets demonstrated the exopolysaccharides of Synechocystis sp. and Rhodella reticulata. Antimicrobial activity was proven for phycobiliproteins isolated from Synechocystis sp., Arthrospira fusiformis, Porphyridium aerugineum and Porphyridium cruentum, respectively. In conclusion Gloeocapsa sp. and Synechocystis sp. and especially their exopolysaccharides showed the most promising potential against the examined food pathogens.     

NUMERICAL INVESTIGATION OF TWO-DIMENSIONAL LAMINAR FLOW AND SOLUTE TRANSPORT IN A CHANNEL WITH SOME SYMMETRIC EXPANSIONS AND CONTRACTIONS

Numerical investigation of two-dimensional (2D) laminar flow and solute transport in a channel with some sudden symmetric expansions and contractions has been performed using the fictitious regions method. This method allows us, instead of solving Navier-Stokes equations in a complex domain, to solve equations with suitably continued coefficients in a rectangle. Stream function-vorticity variables are used in the present paper. Dependence of the flow and solute transport from the dimensions of the channel expansions and contractions is numerically investigated for different values of Reynolds and Péclet numbers using a finite differences method on a relatively fine grid.     

Preparation and characterization of Co-Ru/TiO2/MWCNTs electrocatalysts in PEM hydrogen electrolyzer

The subject of this study is preparation and characterization of hypo-hyper d-electrocatalysts with reduced amount of precious metals aimed for water electrolysis. The studied electrocatalysts contain 10% mixed metallic phase (Co:Ru = 1:1 wt., Co:Ru = 4:1 wt. and Co:Ru:Pt = 4:0.5:0.5 wt.), 18% TiO₂ as a crystalline anatase deposited on multiwalled carbon nanotubes (MWCNTs). Previously, MWCNTs were activated in 28% nitric acid. As a reference electrocatalyst for hydrogen evolution reaction, corresponding electrocatalysts with pure Pt metallic phase and mixed CoPt (Co:Pt = 1:1 wt.) metallic phase were prepared. Also, as a reference electrocatalyst for oxygen evolution reaction, electrocatalyst with pure Ru metallic phase was prepared.The prepared electrocatalysts were structurally characterized by means of XPS, XRD, TEM, SEM and FTIR analysis.Electrochemical characterization was performed by means of cyclic voltammetry and potentiodynamic method in the PEM hydrogen electrolyzer. The range of the catalytic activity for hydrogen evolution of studied electrocatalysts was the following: CoRuPt (4:0.5:0.5) > CoPt (1:1) > Pt > CoRu (1:1) > CoRu (4:1). The order of the catalytic activity for oxygen evolution was the following: CoRu (1:1) > Ru > CoRu (4:1) > Pt > CoRuPt (4:0.5:0.5) > CoPt (1:1).     

Study of the filter cake formed due to the sedimentation of monodispersed and bidispersed particles using discrete element method–computational fluid dynamics simulations

This study aims to investigate the sedimentation and the consolidation of the packed bed/cake formed due to the monodispersed and bidispersed particles under different flow conditions. Mutual interactions between the bidispersed particles and the liquid are considered by using a polydispersed drag model. The attractive force is considered by using the JKR model. Sensitivity of the void fraction of a sedimented packed bed/cake due to particle–particle interaction parameters is studied. Furthermore, the effect of the fluid flow is analyzed by performing the simulations in two stages. In the first stage, packed bed/cake is formed by the sedimentation of the particles in the absence of the fluid forces and in the second stage flow through the packed bed/cake is simulated by using the CFD coupled with the discrete element method. Based on the simulations, correlations between the sedimented and the consolidated void fractions are developed. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1294–1303, 2019     

Method for computing the milk losses from sterility in cows

An attempt was made to work out a method and establish the indices in calculating the losses of milk due to sterility in cows, along with recording the level of productivity and the duration of the period of sterility. The differences were established between: 1. The size of the average daily milk yield per normative day (a day of the period between calvings of 365 days) and that per day of the actual period between calvings. 2. The average daily milk yield per normative day and that per day of the period of sterility. The milk losses calculated in both ways gave almost comparable results. It is , therefore, suggested when calculating the losses due to sterility to use the established indices of milk losses per sterility day (Table 2) at a varying milkiness of the cows and a varying length of the period between calvings, resp., the period of sterility.     

On the effect of various active carbon catalysts on the behaviour of carbon gas-diffusion air electrodes: 1. Alkaline solutions

The electrochemical behaviour of carbon gas-diffusion air electrodes in alkaline solutions was investigated. Electrodes with defined structural and hydrophobic properties were chosen as a suitable system for comparing the electrochemical activity of different active carbon catalysts. The current-voltage characteristics of electrodes with 11 different active carbon catalysts were investigated when operating both with air and pure oxygen. The mass transport hindrances of the electrodes were studied in terms of ΔE(i) curves. Potential recovery transients of the electrodes were correlated with the electrochemical activity of the different active carbon catalysts. On the basis of the experimental results the active carbon sample with the most suitable structural properties was chosen as a proper carrier to be promoted with small amounts of metal catalyst. The electrode with active carbon promoted with small amounts of metal catalyst. The electrode with active carbon promoted with 1.5/cm² silver loaded with 100 mA/cm² has a potential of ?67 mV (vs. Hg/HgO) when operating with oxygen and ?106 mV when operating with air at room temperature.     

Comparative methods for the estimation of the activity and the transport hindrances of air gas-diffusion electrodes

Comparative methods are developed for the estimation of the activity and the transport hindrances of air gas-diffusion electrodes. The value of the intThese methods are successfully employed for the investigation of air electrodes in alkaline solution. Different porous hydrophobic materials are invest