The application of lead dioxide-coated titanium anode in the electroflotation of palm oil mill effluent

The electroflotation of palm oil mill effluent (POME) using lead dioxide-coated titanium anode on a laboratory scale was described. The anode was found to be corrosion-resistant under the conditions of the experiment. The feasibility of the process was determined by monitoring the effluent quality as a function of electrolysis time. Simultaneous flotation of suspended particles and anodic destruction of soluble substances in POME were observed. About 40% of the COD of the dissolved substances of POME could be anodically destroyed together with 86% of suspended particles, made up of mainly plant cell debris, floated off. It is envisaged the electroflotation process could form the first stage of a treatment system with aerobic or physicochemical process as secondary treatment step.     

Fabrication of a pilot scale module of thin film composite hollow fiber membrane for osmotic pressure‐driven processes

Polyamide thin film composite hollow fiber membranes have advantages in their unique structure compared to flat sheet membranes. This study examined interfacial polymerization methods for fabricating pilot scale hollow fiber membranes (membrane area: 1.2 m², number of hollow fiber strands: 1200). For use in osmotic pressure‐driven processes, a one‐pot hydrophilic interfacial polymerization procedure was developed simultaneously to modify the surface property and synthesize polyamide thin film. With the procedure, a pilot scale module has a water flux of 13 LMH using a draw solution of 0.6M NaCl and a feed solution of distilled water through the design of the module configuration. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46110.     

Continuous operation of membrane bioreactor treating toluene vapors by Burkholderia vietnamiensis G4

A laboratory-scale biofilm membrane bioreactor inoculated with Burkholderia vietnamiensis G4 was examined to treat toluene vapors in a waste gas stream. The gas feed side and nutrient solution were separated by a composite membrane consisting of a porous polyacrylonitrile (PAN) support layer coated with a very thin (0.3 μm) dense polydimethylsiloxane (PDMS) top layer. After inoculation, a biofilm developed on the dense layer. The biofilm membrane bioreactor was operated continuously at different residence times (28–2 s) and loading rates (1.2–26.7 kg m⁻³ d⁻¹), with inlet toluene concentrations ranging from 0.21 to 4.1 g m⁻³. The overall performance of the membrane bioreactor was evaluated over a period of 165 days. Removal efficiencies ranging from 78% to 99% and elimination capacities from 4.2 to 14.4 kg m⁻³ d⁻¹ were observed after start-up period depending on the mode of operation. A maximum elimination capacity of 14.4 kg m⁻³ d⁻¹ was observed at a loading rate of 17.4 kg m⁻³ d⁻¹. Overall, the results illustrate that biofilm membrane reactors can potentially be more effective than conventional biofilters and biotrickling filters for the treatment of air pollutants such as toluene.     

Numerical calculation of particle transport in turbulent wall bounded flows

The past 25 years has seen particle technology grow from an under-funded and widely scattered research enterprise to a thriving globally recognized engineering discipline. Despite this change in the research environment, design and analysis of industrial particulate processes remain rooted in empiricism. Scale-up is largely heuristic, and quantitative design methods are non-existent. This is in stark contrast to fluid-phase systems, for which accurate scale-up and design methods have existed for decades.Why is this? One explanation lies in the traditional approaches to studying particle technology operations. Typically, these are studied at two length scales: the macroscale (unit operation level) and the microscale (particle level). Relatively little attention has been directed at an intermediate length scale, the mesoscale, which is characteristic of a “homogeneous” powder. This situation is analogous to ignoring classical thermodynamics and transport properties of fluids in the analysis of fluid-phase operations, instead trying to model unit operation performance directly using statistical mechanics or molecular dynamics.Advances in the design and analysis of particle technology operations requires filling of this “scale gap.” This can be accomplished by studying particulate systems in an analogous way to that used to study fluid-phase unit operations. This will require detailed investigation of mass, momentum, and energy transport in existing unit operations; development of experimental systems with well-defined and characterized flow fields; measurement of powder properties (transport properties and transformation kinetics) in these “simple” experimental systems; validation of theory and simulation against these data; and integration of these theories and simulations into system-level models.     

Synthesis of LiNi0.9Co0.1O2 from Li2CO3, NiO or NiCO3, and CoCO3 or Co3O4 and their electrochemical properties

Cathode active materials with a composition of LiNi_0.9Co_0.1O₂ were synthesized by a solid-state reaction method at 850 °C using Li₂CO₃, NiO or NiCO₃, and CoCO₃ or Co₃O₄, as the sources of Li, Ni, and Co, respectively. Electrochemical properties, structure, and microstructure of the synthesized LiNi_0.9Co_0.1O₂ samples were analyzed. The curves of voltage vs. x in Li_xNi_0.9Co_0.1O₂ for the first charge–discharge and the intercalated and deintercalated Li quantity Δx were studied. The destruction of unstable 3b sites and phase transitions were discussed from the first and second charge–discharge curves of voltage vs. x in Li_xNi_0.9Co_0.1O₂. The LiNi_0.9Co_0.1O₂ sample synthesized from Li₂CO₃, NiO, and Co₃O₄ had the largest first discharge capacity (151 mA h/g), with a discharge capacity deterioration rate of −0.8 mA h/g/cycle (that is, a discharge capacity increasing 0.8 mA h/g per cycle).     

Effect of Repetitive Lysine-Tryptophan Motifs on the Eukaryotic Membrane

In a previous study, we synthesized a series of peptides containing simple sequence repeats, (KW)_n–NH₂ (n = 2,3,4 and 5) and determined their antimicrobial and hemolytic activities, as well as their mechanism of antimicrobial action. However, (KW)₅ showed undesirable cytotoxicity against RBC cells. In order to identify the mechanisms behind the hemolytic and cytotoxic activities of (KW)₅, we measured the ability of these peptides to induce aggregation of liposomes. In addition, their binding and permeation activities were assessed by Trp fluorescence, calcein leakage and circular dichrorism using artificial phospholipids that mimic eukaryotic liposomes, including phosphatidylcholine (PC), PC/sphingomyelin (SM) (2:1, w/w) and PC/cholesterol (CH) (2:1, w/w). Experiments confirmed that only (KW)₅ induced aggregation of all liposomes; it formed much larger aggregates with PC:CH (2:1, w/w) than with PC or PC:SM (2:1, w/w). Longer peptide (KW)₅, but not (KW)₃ or (KW)₄, strongly bound and partially inserted into PC:CH compared to PC or PC:SM (2:1, w/w). Calcein release experiments showed that (KW)₅ induced calcein leakage from the eukaryotic membrane. Greater calcein leakage was induced by (KW)₅ from PC:CH than from PC:SM (2:1, w/w) or PC, whereas (KW)₄ did not induce calcein leakage from any of the liposomes. Circular dichroism measurements indicated that (KW)₅ showed higher conformational transition compared to (KW)₄ due to peptide-liposome interactions. Taken together, our results suggest that (KW)₅ reasonably mediates the aggregation and permeabilization of eukaryotic membranes, which could in turn explain why (KW)₅ displays efficient hemolytic activity.     

PG-2, a Potent AMP against Pathogenic Microbial Strains,from Potato (Solanum tuberosum L cv. Gogu Valley) Tubers Not Cytotoxic against Human Cells

In an earlier study, we isolated potamin-1 (PT-1), a 5.6-kDa trypsin-chymotrypsin protease inhibitor, from the tubers of a potato strain (Solanum tuberosum L cv. Gogu Valley). We established that PT-1 strongly inhibits pathogenic microbial strains, but not human bacterial strains, and that its sequence shows 62% homology with a serine protease inhibitor. In the present study, we isolated an antifungal and antibacterial peptide with no cytotoxicity from tubers of the same potato strain. The peptide (peptide-G2, PG-2) was isolated using salt-extraction, ultrafiltration and reverse-phase high performance liquid chromatography (RP-HPLC). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) showed the protein to have a molecular mass of 3228.5 Da, while automated Edman degradation showed the N-terminal sequence of PG-2 to be LVKDNPLDISPKQVQALCTDLVIRCMCCC-. PG-2 exhibited antimicrobial activity against Candida albicans, a human pathogenic yeast strain, and Clavibacter michiganensis subsp. michiganensis, a plant late blight strain. PG-2 also showed antibacterial activity against Staphylococcus aureus, but did not lyse human red blood cells and was thermostable. Overall, these results suggest PG-2 may be a good candidate to serve as a natural antimicrobial agent, agricultural pesticide and/or food additive.     

Polyacrylonitrile‐carbon Nanotube‐polyacrylonitrile: A Versatile Robust Platform for Flexible Multifunctional Electronic Devices in Medical Applications

Flexible multifunctional electronic devices are of high interest for a wide range of applications including thermal therapy and respiratory devices in medical treatment, safety equipment, and structural health monitoring systems. This paper reports a scalable and efficient strategy of manufacturing a polyacrylonitrile‐carbon nanotube‐polyacrylonitrile (PAN‐CNT‐PAN) robust flexible platform for multifunctional electronic devices including flexible heaters, temperature sensors, and flexible thermal flow sensors. The key advantages of this platform include low cost, porosity, mechanical robustness, and electrical stability under mechanical bending, enabling the development of fast‐response flexible heaters with a response time of ≈1.5 s and relaxation time of ≈1.7 s. The temperature‐sensing functionality is also investigated with a range of temperature coefficient of resistances from ?650 to ?900 ppm K^?1. A flexible hot‐film sensing concept is successfully demonstrated using PAN‐CNT‐PAN with a high sensitivity of 340 mV (m s^?1)^?1. The sensitivity enhancement of 50% W^?1 is also observed with increasing supply power. The low cost, porosity, versatile, and robust properties of the proposed platform will enable the development of multifunctional electronic devices for numerous applications such as flexible thermal management, temperature stabilization in industrial processing, temperature sensing, and flexible/wearable devices for human healthcare applications.     

Pr3+/Er3+ Codoped Ge-As-Ga-S Glasses as Dual-Wavelength Fiber-optic Amplifiers for 1.31 and 1.55 μm Windows

Fluorescence emissions at both 1.31 and 1.55 μm communication windows were observed from Pr³⁺/Er³⁺ codoped Ge-As-Ga-S glasses with a single wavelength pumping at 986 nm. The lifetime of the Er³⁺:⁴ I _11/2 level decreased as the Pr³⁺ concentration increased, and that of the Pr³⁺:¹ G ₄ level increased as the Er³⁺ concentration increased. Energy transfer from the Er³⁺:⁴ I _11/2 level to the Pr³⁺:¹ G ₄ level was responsible for emission of the 1.31 μm fluorescence from the Pr³⁺:¹ G ₄ level. Ge-As-Ga-S glasses that have been doped with Pr³⁺ and Er³⁺ cations are promising amplifier materials for both 1.31 and 1.55 μm communication windows.