Improving the Removal Efficiency of Cyclones by Recycle Stream

An innovative way to increase the overall efficiency of a cyclone is presented. By recycling a fraction of the output stream to the inlet duct, the efficiency of the cyclone can be improved. Experiments were conducted using bench scale (0.1 m diameter) and pilot scale (0.456 m diameter) cyclones. The overall efficiency was evaluated for both cyclones at different ranges of recycle ratios. In the presence of the recycle stream, the efficiency increases in a monotonic manner. It may approach 100 % with the use of very high recycle ratios, provided that there is agglomeration of the fine particles available in the feed stream and/or adhesion of fines to the coarse particles. From the experimental results, it is observed that the agglomeration of fine particles is the most important factor for improving the cyclone efficiency by use of a recycle stream. Moreover, the effect of the recycle stream persists, even if the inlet velocity surpasses the saltation velocity of the cyclone.     

Ballistic limit evaluation for impact of cylindrical projectiles on honeycomb panels

In this paper the perforation of honeycomb panels under impact of cylindrical projectiles is studied and the ballistic limit velocity is determined by the energy method. The results show that the increase of panel thickness, compression and shear yield strengths and cell wall thickness increase the ballistic limit velocity, while an increase in the size of the cell and projectile mass decrease it. These results are in good agreement with available experimental data.     

Microencapsulation of Lactobacillus paracasei by spray freeze drying

This study evaluates the implementation of a new process: spray freeze drying (SFD), to produce dry micro-capsules of Lactobacillus paracasei with high viability. The study concentrated on determining the survival of the cells, encapsulated in a matrix of maltodextrin and trehalose. SFD was compared with the conventional bulk freeze drying (BFD). Overall it was shown that SFD is a successful method to generate dry micro-capsules of probiotic cells with high viability (>60%). The spraying stage did not affect the viability of the bacteria. In the freezing stage, high osmotic pressures originated by elevated trehalose concentrations, helped preserving the cells viability. It was also found that the lower the maltodextrin molecular weight, the larger the beads volume and solids concentration, the higher is the bacteria survival during the freezing and drying stages. In the drying stage, trehalose concentration was also the critical factor that increased final probiotic viability.     

The Development of Antimicrobial α‐AApeptides that Suppress Proinflammatory Immune Responses

Herein we describe the development of a new class of antimicrobial and anti‐inflammatory peptidomimetics: cyclic lipo‐α‐AApeptides. They have potent and broad‐spectrum antibacterial activity against a range of clinically relevant pathogens, including both multidrug‐resistant Gram‐positive and Gram‐negative bacteria. Fluorescence microscopy suggests that cyclic lipo‐α‐AApeptides kill bacteria by disrupting bacterial membranes, possibly through a mechanism similar to that of cationic host‐defense peptides (HDPs). Furthermore, the cyclic lipo‐α‐AApeptide can mimic cationic host‐defense peptides by antagonizing Toll‐like receptor 4 (TLR4) signaling responses and suppressing proinflammatory cytokines such as tumor necrosis factor‐α (TNF‐α). Our results suggest that by mimicking HDPs, cyclic lipo‐α‐AApeptides could emerge as a new class of antibiotic agents that directly kill bacteria, as well as novel antiinflammatory agents that act through immunomodulation.     

An enhanced LQ adaptive VAr unit controller for power systemdamping

An adaptive linear quadratic Gaussian control strategy is presented for static VAr compensators to enhance power system damping and stability. The control strategy utilizes only local information to dampen oscillatory modes present in the network. The controller calculates an appropriate value of static VAr compensator susceptance to present to the network at each sampling interval based on a reduced-order model of the power system. The reduced-order model is obtained online by a least-squares identifier. Simulation results for a nine-bus network are presented     

Effect of cholesterol on the physical properties of pulmonary surfactant films: atomic force measurements study

Atomic force measurements were performed on supported pulmonary surfactant (PS) films to address the effect of cholesterol on the physical properties of lung surfactant films. We recently found that cholesterol in excess of a physiological proportion abolishes surfactant function, and is the reason that surfactant fails to lower the surface tension upon compression. In this study, we investigated how the loss of mechanical stability observed earlier is related to the local mechanical properties of the film by local force measurements. The presence of 20% of cholesterol in bovine lipid extract surfactant (BLES) resulted in a decrease of the observed adhesive interaction, and an increase in rigidity of the film. We discuss the implication the increased rigidity might have on the functional failure of PS.     

Donation Center Location Problem

We introduce and study the donation center location problem, which has an additional application in network testing and may also be of independent interest as a general graph-theoretic problem. Given a set of agents and a set of centers, where agents have preferences over centers and centers have capacities, the goal is to open a subset of centers and to assign a maximum-sized subset of agents to their most-preferred opened centers, while respecting the capacity constraints. We prove that in general, the problem is hard to approximate within n ^1/2?? for any ?>0. In view of this, we investigate two special cases. In one, every agent has a bounded number of centers on its preference list, and in the other, all preferences are induced by a line-metric. We present constant-factor approximation algorithms for the former and exact polynomial-time algorithms for the latter.     

Water and heat regimes modelling for a vast territory using remote-sensing data

Methods have been developed to assess water and heat regime characteristics of a vast agricultural region for vegetation season based on the model of land-surface–atmosphere interaction. The model is adjusted to assimilate estimates of the land-surface and meteorological characteristics derived from Advanced Very High Resolution Radiometer/National Oceanic and Atmospheric Administration (AVHRR/NOAA), Moderate Resolution Imaging Spectroradiometer/Earth Observing System Terra & Aqua (MODIS/EOS Terra and Aqua), and Scanning Enhanced Visible and Infrared Imager/Meteosat-9 (SEVIRI/Meteosat-9) data. The case study has been carried out for the agricultural Central Black Earth region of European Russia of 227,300 km² for the 2009–2012 vegetation seasons. The methods of satellite data processing have been developed or refined, which provide the retrieval of vegetation characteristics, land-surface temperature, and precipitation. The techniques for the assimilation of satellite-based products in the model have been developed. Some major water regime characteristics have been generated such as soil water content, evapotranspiration, and others.     

A general approach to low noise readout of terahertz imaging arrays

This article describes the theory and design of an ultra-low noise electronic readout circuit for use with room temperature video-rate terahertz imaging arrays. First, the noise characteristics of various imaging detectors, including low resistance bolometers and high resistance diodes are discussed. Theoretical approaches to white and 1/f noise mitigation are examined, and a corresponding low-noise readout circuit is designed, built, and tested. It is shown that the circuit is capable of achieving detector limited noise performance for use in room temperature terahertz imaging systems. A thorough noise analysis of the circuit provides the necessary information for applying the readout circuit to any type of imaging detector, and more generally, any measurement of small signals from various source impedances in the presence of white and 1/f noise. W-band measurements of an 8-element, high-resistance detector array, and a 32-element, low-resistance detector array demonstrate the usefulness of the readout circuit. Finally, recommended circuit configurations for various detectors in the literature are provided, with theoretical performance metrics summarized.     

Experimental and analytical assessment of axial crushing of circular hybrid tubes under quasi-static load

In the present article, axial crushing behavior of circular aluminum/glass–epoxy hybrid tubes is studied experimentally and analytically. 48 quasi-static axial crushing experiments are carried out on bare metal and hybrid tubes to evaluate the effect of different parameters such as metal and composite wall thicknesses and stacking sequence of composite layers on the crashworthiness characteristics. The specimens are made in two types of layups including angle ply pattern [±θ]_s and multi angle ply pattern (different ply angles). The experimental results reveal that stacking sequence has a considerable effect on crashworthiness characteristics, for example for layup [90/0/0/90], the absorbed energy is more than three times of aluminum tube with the same aluminum wall thickness. Also the aforementioned layup has better energy absorption compared to [90/90/90/90] which has been previously proposed as the best layup.